@article{ZieglerPfitznerSchulzetal.2022, author = {Ziegler, Joceline and Pfitzner, Bjarne and Schulz, Heinrich and Saalbach, Axel and Arnrich, Bert}, title = {Defending against Reconstruction Attacks through Differentially Private Federated Learning for Classification of Heterogeneous Chest X-ray Data}, series = {Sensors}, volume = {22}, journal = {Sensors}, edition = {14}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {1424-8220}, doi = {10.3390/s22145195}, pages = {25}, year = {2022}, abstract = {Privacy regulations and the physical distribution of heterogeneous data are often primary concerns for the development of deep learning models in a medical context. This paper evaluates the feasibility of differentially private federated learning for chest X-ray classification as a defense against data privacy attacks. To the best of our knowledge, we are the first to directly compare the impact of differentially private training on two different neural network architectures, DenseNet121 and ResNet50. Extending the federated learning environments previously analyzed in terms of privacy, we simulated a heterogeneous and imbalanced federated setting by distributing images from the public CheXpert and Mendeley chest X-ray datasets unevenly among 36 clients. Both non-private baseline models achieved an area under the receiver operating characteristic curve (AUC) of 0.940.94 on the binary classification task of detecting the presence of a medical finding. We demonstrate that both model architectures are vulnerable to privacy violation by applying image reconstruction attacks to local model updates from individual clients. The attack was particularly successful during later training stages. To mitigate the risk of a privacy breach, we integrated R{\´e}nyi differential privacy with a Gaussian noise mechanism into local model training. We evaluate model performance and attack vulnerability for privacy budgets ε∈{1,3,6,10}�∈{1,3,6,10}. The DenseNet121 achieved the best utility-privacy trade-off with an AUC of 0.940.94 for ε=6�=6. Model performance deteriorated slightly for individual clients compared to the non-private baseline. The ResNet50 only reached an AUC of 0.760.76 in the same privacy setting. Its performance was inferior to that of the DenseNet121 for all considered privacy constraints, suggesting that the DenseNet121 architecture is more robust to differentially private training.}, language = {en} } @article{ZhouFischerTuncaetal.2020, author = {Zhou, Lin and Fischer, Eric and Tunca, Can and Brahms, Clemens Markus and Ersoy, Cem and Granacher, Urs and Arnrich, Bert}, title = {How We Found Our IMU}, series = {Sensors}, volume = {20}, journal = {Sensors}, number = {15}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s20154090}, pages = {29}, year = {2020}, abstract = {Inertial measurement units (IMUs) are commonly used for localization or movement tracking in pervasive healthcare-related studies, and gait analysis is one of the most often studied topics using IMUs. The increasing variety of commercially available IMU devices offers convenience by combining the sensor modalities and simplifies the data collection procedures. However, selecting the most suitable IMU device for a certain use case is increasingly challenging. In this study, guidelines for IMU selection are proposed. In particular, seven IMUs were compared in terms of their specifications, data collection procedures, and raw data quality. Data collected from the IMUs were then analyzed by a gait analysis algorithm. The difference in accuracy of the calculated gait parameters between the IMUs could be used to retrace the issues in raw data, such as acceleration range or sensor calibration. Based on our algorithm, we were able to identify the best-suited IMUs for our needs. This study provides an overview of how to select the IMUs based on the area of study with concrete examples, and gives insights into the features of seven commercial IMUs using real data.}, language = {en} } @article{ZennerBoettingerKonigorski2022, author = {Zenner, Alexander M. and B{\"o}ttinger, Erwin and Konigorski, Stefan}, title = {StudyMe}, series = {Trials}, volume = {23}, journal = {Trials}, publisher = {BioMed Central}, address = {London}, issn = {1745-6215}, doi = {10.1186/s13063-022-06893-7}, pages = {15}, year = {2022}, abstract = {N-of-1 trials are multi-crossover self-experiments that allow individuals to systematically evaluate the effect of interventions on their personal health goals. Although several tools for N-of-1 trials exist, there is a gap in supporting non-experts in conducting their own user-centric trials. In this study, we present StudyMe, an open-source mobile application that is freely available from https://play.google.com/store/apps/details?id=health.studyu.me and offers users flexibility and guidance in configuring every component of their trials. We also present research that informed the development of StudyMe, focusing on trial creation. Through an initial survey with 272 participants, we learned that individuals are interested in a variety of personal health aspects and have unique ideas on how to improve them. In an iterative, user-centered development process with intermediate user tests, we developed StudyMe that features an educational part to communicate N-of-1 trial concepts. A final empirical evaluation of StudyMe showed that all participants were able to create their own trials successfully using StudyMe and the app achieved a very good usability rating. Our findings suggest that StudyMe provides a significant step towards enabling individuals to apply a systematic science-oriented approach to personalize health-related interventions and behavior modifications in their everyday lives.}, language = {en} } @article{YousfiHeweltBaueretal.2018, author = {Yousfi, Alaaeddine and Hewelt, Marcin and Bauer, Christine and Weske, Mathias}, title = {Toward uBPMN-Based patterns for modeling ubiquitous business processes}, series = {IEEE Transactions on Industrial Informatics}, volume = {14}, journal = {IEEE Transactions on Industrial Informatics}, number = {8}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Piscataway}, issn = {1551-3203}, doi = {10.1109/TII.2017.2777847}, pages = {3358 -- 3367}, year = {2018}, abstract = {Ubiquitous business processes are the new generation of processes that pervade the physical space and interact with their environments using a minimum of human involvement. Although they are now widely deployed in the industry, their deployment is still ad hoc . They are implemented after an arbitrary modeling phase or no modeling phase at all. The absence of a solid modeling phase backing up the implementation generates many loopholes that are stressed in the literature. Here, we tackle the issue of modeling ubiquitous business processes. We propose patterns to represent the recent ubiquitous computing features. These patterns are the outcome of an analysis we conducted in the field of human-computer interaction to examine how the features are actually deployed. The patterns' understandability, ease-of-use, usefulness, and completeness are examined via a user experiment. The results indicate that these four indexes are on the positive track. Hence, the patterns may be the backbone of ubiquitous business process modeling in industrial applications.}, language = {en} } @article{YousfiBatoulisWeske2019, author = {Yousfi, Alaaeddine and Batoulis, Kimon and Weske, Mathias}, title = {Achieving Business Process Improvement via Ubiquitous Decision-Aware Business Processes}, series = {ACM Transactions on Internet Technology}, volume = {19}, journal = {ACM Transactions on Internet Technology}, number = {1}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {1533-5399}, doi = {10.1145/3298986}, pages = {19}, year = {2019}, abstract = {Business process improvement is an endless challenge for many organizations. As long as there is a process, it must he improved. Nowadays, improvement initiatives are driven by professionals. This is no longer practical because people cannot perceive the enormous data of current business environments. Here, we introduce ubiquitous decision-aware business processes. They pervade the physical space, analyze the ever-changing environments, and make decisions accordingly. We explain how they can be built and used for improvement. Our approach can be a valuable improvement option to alleviate the workload of participants by helping focus on the crucial rather than the menial tasks.}, language = {en} } @phdthesis{Yang2019, author = {Yang, Haojin}, title = {Deep representation learning for multimedia data analysis}, school = {Universit{\"a}t Potsdam}, pages = {278}, year = {2019}, language = {en} } @article{WuttkeLiLietal.2019, author = {Wuttke, Matthias and Li, Yong and Li, Man and Sieber, Karsten B. and Feitosa, Mary F. and Gorski, Mathias and Tin, Adrienne and Wang, Lihua and Chu, Audrey Y. and Hoppmann, Anselm and Kirsten, Holger and Giri, Ayush and Chai, Jin-Fang and Sveinbjornsson, Gardar and Tayo, Bamidele O. and Nutile, Teresa and Fuchsberger, Christian and Marten, Jonathan and Cocca, Massimiliano and Ghasemi, Sahar and Xu, Yizhe and Horn, Katrin and Noce, Damia and Van der Most, Peter J. and Sedaghat, Sanaz and Yu, Zhi and Akiyama, Masato and Afaq, Saima and Ahluwalia, Tarunveer Singh and Almgren, Peter and Amin, Najaf and Arnlov, Johan and Bakker, Stephan J. L. and Bansal, Nisha and Baptista, Daniela and Bergmann, Sven and Biggs, Mary L. and Biino, Ginevra and Boehnke, Michael and Boerwinkle, Eric and Boissel, Mathilde and B{\"o}ttinger, Erwin and Boutin, Thibaud S. and Brenner, Hermann and Brumat, Marco and Burkhardt, Ralph and Butterworth, Adam S. and Campana, Eric and Campbell, Archie and Campbell, Harry and Canouil, Mickael and Carroll, Robert J. and Catamo, Eulalia and Chambers, John C. and Chee, Miao-Ling and Chee, Miao-Li and Chen, Xu and Cheng, Ching-Yu and Cheng, Yurong and Christensen, Kaare and Cifkova, Renata and Ciullo, Marina and Concas, Maria Pina and Cook, James P. and Coresh, Josef and Corre, Tanguy and Sala, Cinzia Felicita and Cusi, Daniele and Danesh, John and Daw, E. Warwick and De Borst, Martin H. and De Grandi, Alessandro and De Mutsert, Renee and De Vries, Aiko P. J. and Degenhardt, Frauke and Delgado, Graciela and Demirkan, Ayse and Di Angelantonio, Emanuele and Dittrich, Katalin and Divers, Jasmin and Dorajoo, Rajkumar and Eckardt, Kai-Uwe and Ehret, Georg and Elliott, Paul and Endlich, Karlhans and Evans, Michele K. and Felix, Janine F. and Foo, Valencia Hui Xian and Franco, Oscar H. and Franke, Andre and Freedman, Barry I. and Freitag-Wolf, Sandra and Friedlander, Yechiel and Froguel, Philippe and Gansevoort, Ron T. and Gao, He and Gasparini, Paolo and Gaziano, J. Michael and Giedraitis, Vilmantas and Gieger, Christian and Girotto, Giorgia and Giulianini, Franco and Gogele, Martin and Gordon, Scott D. and Gudbjartsson, Daniel F. and Gudnason, Vilmundur and Haller, Toomas and Hamet, Pavel and Harris, Tamara B. and Hartman, Catharina A. and Hayward, Caroline and Hellwege, Jacklyn N. and Heng, Chew-Kiat and Hicks, Andrew A. and Hofer, Edith and Huang, Wei and Hutri-Kahonen, Nina and Hwang, Shih-Jen and Ikram, M. Arfan and Indridason, Olafur S. and Ingelsson, Erik and Ising, Marcus and Jaddoe, Vincent W. V. and Jakobsdottir, Johanna and Jonas, Jost B. and Joshi, Peter K. and Josyula, Navya Shilpa and Jung, Bettina and Kahonen, Mika and Kamatani, Yoichiro and Kammerer, Candace M. and Kanai, Masahiro and Kastarinen, Mika and Kerr, Shona M. and Khor, Chiea-Chuen and Kiess, Wieland and Kleber, Marcus E. and Koenig, Wolfgang and Kooner, Jaspal S. and Korner, Antje and Kovacs, Peter and Kraja, Aldi T. and Krajcoviechova, Alena and Kramer, Holly and Kramer, Bernhard K. and Kronenberg, Florian and Kubo, Michiaki and Kuhnel, Brigitte and Kuokkanen, Mikko and Kuusisto, Johanna and La Bianca, Martina and Laakso, Markku and Lange, Leslie A. and Langefeld, Carl D. and Lee, Jeannette Jen-Mai and Lehne, Benjamin and Lehtimaki, Terho and Lieb, Wolfgang and Lim, Su-Chi and Lind, Lars and Lindgren, Cecilia M. and Liu, Jun and Liu, Jianjun and Loeffler, Markus and Loos, Ruth J. F. and Lucae, Susanne and Lukas, Mary Ann and Lyytikainen, Leo-Pekka and Magi, Reedik and Magnusson, Patrik K. E. and Mahajan, Anubha and Martin, Nicholas G. and Martins, Jade and Marz, Winfried and Mascalzoni, Deborah and Matsuda, Koichi and Meisinger, Christa and Meitinger, Thomas and Melander, Olle and Metspalu, Andres and Mikaelsdottir, Evgenia K. and Milaneschi, Yuri and Miliku, Kozeta and Mishra, Pashupati P. and Program, V. A. Million Veteran and Mohlke, Karen L. and Mononen, Nina and Montgomery, Grant W. and Mook-Kanamori, Dennis O. and Mychaleckyj, Josyf C. and Nadkarni, Girish N. and Nalls, Mike A. and Nauck, Matthias and Nikus, Kjell and Ning, Boting and Nolte, Ilja M. and Noordam, Raymond and Olafsson, Isleifur and Oldehinkel, Albertine J. and Orho-Melander, Marju and Ouwehand, Willem H. and Padmanabhan, Sandosh and Palmer, Nicholette D. and Palsson, Runolfur and Penninx, Brenda W. J. H. and Perls, Thomas and Perola, Markus and Pirastu, Mario and Pirastu, Nicola and Pistis, Giorgio and Podgornaia, Anna I. and Polasek, Ozren and Ponte, Belen and Porteous, David J. and Poulain, Tanja and Pramstaller, Peter P. and Preuss, Michael H. and Prins, Bram P. and Province, Michael A. and Rabelink, Ton J. and Raffield, Laura M. and Raitakari, Olli T. and Reilly, Dermot F. and Rettig, Rainer and Rheinberger, Myriam and Rice, Kenneth M. and Ridker, Paul M. and Rivadeneira, Fernando and Rizzi, Federica and Roberts, David J. and Robino, Antonietta and Rossing, Peter and Rudan, Igor and Rueedi, Rico and Ruggiero, Daniela and Ryan, Kathleen A. and Saba, Yasaman and Sabanayagam, Charumathi and Salomaa, Veikko and Salvi, Erika and Saum, Kai-Uwe and Schmidt, Helena and Schmidt, Reinhold and Ben Schottker, and Schulz, Christina-Alexandra and Schupf, Nicole and Shaffer, Christian M. and Shi, Yuan and Smith, Albert V. and Smith, Blair H. and Soranzo, Nicole and Spracklen, Cassandra N. and Strauch, Konstantin and Stringham, Heather M. and Stumvoll, Michael and Svensson, Per O. and Szymczak, Silke and Tai, E-Shyong and Tajuddin, Salman M. and Tan, Nicholas Y. Q. and Taylor, Kent D. and Teren, Andrej and Tham, Yih-Chung and Thiery, Joachim and Thio, Chris H. L. and Thomsen, Hauke and Thorleifsson, Gudmar and Toniolo, Daniela and Tonjes, Anke and Tremblay, Johanne and Tzoulaki, Ioanna and Uitterlinden, Andre G. and Vaccargiu, Simona and Van Dam, Rob M. and Van der Harst, Pim and Van Duijn, Cornelia M. and Edward, Digna R. Velez and Verweij, Niek and Vogelezang, Suzanne and Volker, Uwe and Vollenweider, Peter and Waeber, Gerard and Waldenberger, Melanie and Wallentin, Lars and Wang, Ya Xing and Wang, Chaolong and Waterworth, Dawn M. and Bin Wei, Wen and White, Harvey and Whitfield, John B. and Wild, Sarah H. and Wilson, James F. and Wojczynski, Mary K. and Wong, Charlene and Wong, Tien-Yin and Xu, Liang and Yang, Qiong and Yasuda, Masayuki and Yerges-Armstrong, Laura M. and Zhang, Weihua and Zonderman, Alan B. and Rotter, Jerome I. and Bochud, Murielle and Psaty, Bruce M. and Vitart, Veronique and Wilson, James G. and Dehghan, Abbas and Parsa, Afshin and Chasman, Daniel I. and Ho, Kevin and Morris, Andrew P. and Devuyst, Olivier and Akilesh, Shreeram and Pendergrass, Sarah A. and Sim, Xueling and Boger, Carsten A. and Okada, Yukinori and Edwards, Todd L. and Snieder, Harold and Stefansson, Kari and Hung, Adriana M. and Heid, Iris M. and Scholz, Markus and Teumer, Alexander and Kottgen, Anna and Pattaro, Cristian}, title = {A catalog of genetic loci associated with kidney function from analyses of a million individuals}, series = {Nature genetics}, volume = {51}, journal = {Nature genetics}, number = {6}, publisher = {Nature Publ. Group}, address = {New York}, organization = {Lifelines COHort Study}, issn = {1061-4036}, doi = {10.1038/s41588-019-0407-x}, pages = {957 -- +}, year = {2019}, abstract = {Chronic kidney disease (CKD) is responsible for a public health burden with multi-systemic complications. Through transancestry meta-analysis of genome-wide association studies of estimated glomerular filtration rate (eGFR) and independent replication (n = 1,046,070), we identified 264 associated loci (166 new). Of these,147 were likely to be relevant for kidney function on the basis of associations with the alternative kidney function marker blood urea nitrogen (n = 416,178). Pathway and enrichment analyses, including mouse models with renal phenotypes, support the kidney as the main target organ. A genetic risk score for lower eGFR was associated with clinically diagnosed CKD in 452,264 independent individuals. Colocalization analyses of associations with eGFR among 783,978 European-ancestry individuals and gene expression across 46 human tissues, including tubulo-interstitial and glomerular kidney compartments, identified 17 genes differentially expressed in kidney. Fine-mapping highlighted missense driver variants in 11 genes and kidney-specific regulatory variants. These results provide a comprehensive priority list of molecular targets for translational research.}, language = {en} } @article{WittigMirandaHoelzeretal.2022, author = {Wittig, Alice and Miranda, Fabio Malcher and H{\"o}lzer, Martin and Altenburg, Tom and Bartoszewicz, Jakub Maciej and Beyvers, Sebastian and Dieckmann, Marius Alfred and Genske, Ulrich and Giese, Sven Hans-Joachim and Nowicka, Melania and Richard, Hugues and Schiebenhoefer, Henning and Schmachtenberg, Anna-Juliane and Sieben, Paul and Tang, Ming and Tembrockhaus, Julius and Renard, Bernhard Y. and Fuchs, Stephan}, title = {CovRadar}, series = {Bioinformatics}, volume = {38}, journal = {Bioinformatics}, number = {17}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1367-4803}, doi = {10.1093/bioinformatics/btac411}, pages = {4223 -- 4225}, year = {2022}, abstract = {The ongoing pandemic caused by SARS-CoV-2 emphasizes the importance of genomic surveillance to understand the evolution of the virus, to monitor the viral population, and plan epidemiological responses. Detailed analysis, easy visualization and intuitive filtering of the latest viral sequences are powerful for this purpose. We present CovRadar, a tool for genomic surveillance of the SARS-CoV-2 Spike protein. CovRadar consists of an analytical pipeline and a web application that enable the analysis and visualization of hundreds of thousand sequences. First, CovRadar extracts the regions of interest using local alignment, then builds a multiple sequence alignment, infers variants and consensus and finally presents the results in an interactive app, making accessing and reporting simple, flexible and fast.}, language = {en} } @misc{WelearegaiSchlueterHammer2019, author = {Welearegai, Gebrehiwet B. and Schlueter, Max and Hammer, Christian}, title = {Static security evaluation of an industrial web application}, series = {Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing}, journal = {Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-5933-7}, doi = {10.1145/3297280.3297471}, pages = {1952 -- 1961}, year = {2019}, abstract = {JavaScript is the most popular programming language for web applications. Static analysis of JavaScript applications is highly challenging due to its dynamic language constructs and event-driven asynchronous executions, which also give rise to many security-related bugs. Several static analysis tools to detect such bugs exist, however, research has not yet reported much on the precision and scalability trade-off of these analyzers. As a further obstacle, JavaScript programs structured in Node. js modules need to be collected for analysis, but existing bundlers are either specific to their respective analysis tools or not particularly suitable for static analysis.}, language = {en} } @article{VollmerTrappSchumannetal.2018, author = {Vollmer, Jan Ole and Trapp, Matthias and Schumann, Heidrun and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {Hierarchical spatial aggregation for level-of-detail visualization of 3D thematic data}, series = {ACM transactions on spatial algorithms and systems}, volume = {4}, journal = {ACM transactions on spatial algorithms and systems}, number = {3}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {2374-0353}, doi = {10.1145/3234506}, pages = {23}, year = {2018}, abstract = {Thematic maps are a common tool to visualize semantic data with a spatial reference. Combining thematic data with a geometric representation of their natural reference frame aids the viewer's ability in gaining an overview, as well as perceiving patterns with respect to location; however, as the amount of data for visualization continues to increase, problems such as information overload and visual clutter impede perception, requiring data aggregation and level-of-detail visualization techniques. While existing aggregation techniques for thematic data operate in a 2D reference frame (i.e., map), we present two aggregation techniques for 3D spatial and spatiotemporal data mapped onto virtual city models that hierarchically aggregate thematic data in real time during rendering to support on-the-fly and on-demand level-of-detail generation. An object-based technique performs aggregation based on scene-specific objects and their hierarchy to facilitate per-object analysis, while the scene-based technique aggregates data solely based on spatial locations, thus supporting visual analysis of data with arbitrary reference geometry. Both techniques can apply different aggregation functions (mean, minimum, and maximum) for ordinal, interval, and ratio-scaled data and can be easily extended with additional functions. Our implementation utilizes the programmable graphics pipeline and requires suitably encoded data, i.e., textures or vertex attributes. We demonstrate the application of both techniques using real-world datasets, including solar potential analyses and the propagation of pressure waves in a virtual city model.}, language = {en} } @article{VanHoutTachmazidouBackmanetal.2020, author = {Van Hout, Cristopher V. and Tachmazidou, Ioanna and Backman, Joshua D. and Hoffman, Joshua D. and Liu, Daren and Pandey, Ashutosh K. and Gonzaga-Jauregui, Claudia and Khalid, Shareef and Ye, Bin and Banerjee, Nilanjana and Li, Alexander H. and O'Dushlaine, Colm and Marcketta, Anthony and Staples, Jeffrey and Schurmann, Claudia and Hawes, Alicia and Maxwell, Evan and Barnard, Leland and Lopez, Alexander and Penn, John and Habegger, Lukas and Blumenfeld, Andrew L. and Bai, Xiaodong and O'Keeffe, Sean and Yadav, Ashish and Praveen, Kavita and Jones, Marcus and Salerno, William J. and Chung, Wendy K. and Surakka, Ida and Willer, Cristen J. and Hveem, Kristian and Leader, Joseph B. and Carey, David J. and Ledbetter, David H. and Cardon, Lon and Yancopoulos, George D. and Economides, Aris and Coppola, Giovanni and Shuldiner, Alan R. and Balasubramanian, Suganthi and Cantor, Michael and Nelson, Matthew R. and Whittaker, John and Reid, Jeffrey G. and Marchini, Jonathan and Overton, John D. and Scott, Robert A. and Abecasis, Goncalo R. and Yerges-Armstrong, Laura M. and Baras, Aris}, title = {Exome sequencing and characterization of 49,960 individuals in the UK Biobank}, series = {Nature : the international weekly journal of science}, volume = {586}, journal = {Nature : the international weekly journal of science}, number = {7831}, publisher = {Macmillan Publishers Limited}, address = {London}, organization = {Regeneron Genetics Ctr}, issn = {0028-0836}, doi = {10.1038/s41586-020-2853-0}, pages = {749 -- 756}, year = {2020}, abstract = {The UK Biobank is a prospective study of 502,543 individuals, combining extensive phenotypic and genotypic data with streamlined access for researchers around the world(1). Here we describe the release of exome-sequence data for the first 49,960 study participants, revealing approximately 4 million coding variants (of which around 98.6\% have a frequency of less than 1\%). The data include 198,269 autosomal predicted loss-of-function (LOF) variants, a more than 14-fold increase compared to the imputed sequence. Nearly all genes (more than 97\%) had at least one carrier with a LOF variant, and most genes (more than 69\%) had at least ten carriers with a LOF variant. We illustrate the power of characterizing LOF variants in this population through association analyses across 1,730 phenotypes. In addition to replicating established associations, we found novel LOF variants with large effects on disease traits, includingPIEZO1on varicose veins,COL6A1on corneal resistance,MEPEon bone density, andIQGAP2andGMPRon blood cell traits. We further demonstrate the value of exome sequencing by surveying the prevalence of pathogenic variants of clinical importance, and show that 2\% of this population has a medically actionable variant. Furthermore, we characterize the penetrance of cancer in carriers of pathogenicBRCA1andBRCA2variants. Exome sequences from the first 49,960 participants highlight the promise of genome sequencing in large population-based studies and are now accessible to the scientific community.
Exome sequences from the first 49,960 participants in the UK Biobank highlight the promise of genome sequencing in large population-based studies and are now accessible to the scientific community.}, language = {en} } @article{vanderAaLeopoldWeidlich2020, author = {van der Aa, Han and Leopold, Henrik and Weidlich, Matthias}, title = {Partial order resolution of event logs for process conformance checking}, series = {Decision support systems : DSS}, volume = {136}, journal = {Decision support systems : DSS}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {0167-9236}, doi = {10.1016/j.dss.2020.113347}, pages = {12}, year = {2020}, abstract = {While supporting the execution of business processes, information systems record event logs. Conformance checking relies on these logs to analyze whether the recorded behavior of a process conforms to the behavior of a normative specification. A key assumption of existing conformance checking techniques, however, is that all events are associated with timestamps that allow to infer a total order of events per process instance. Unfortunately, this assumption is often violated in practice. Due to synchronization issues, manual event recordings, or data corruption, events are only partially ordered. In this paper, we put forward the problem of partial order resolution of event logs to close this gap. It refers to the construction of a probability distribution over all possible total orders of events of an instance. To cope with the order uncertainty in real-world data, we present several estimators for this task, incorporating different notions of behavioral abstraction. Moreover, to reduce the runtime of conformance checking based on partial order resolution, we introduce an approximation method that comes with a bounded error in terms of accuracy. Our experiments with real-world and synthetic data reveal that our approach improves accuracy over the state-of-the-art considerably.}, language = {en} } @phdthesis{Ussath2017, author = {Ussath, Martin Georg}, title = {Analytical approaches for advanced attacks}, school = {Universit{\"a}t Potsdam}, pages = {169}, year = {2017}, language = {en} } @article{UlrichLutfiRutzenetal.2022, author = {Ulrich, Jens-Uwe and Lutfi, Ahmad and Rutzen, Kilian and Renard, Bernhard Y.}, title = {ReadBouncer}, series = {Bioinformatics}, volume = {38}, journal = {Bioinformatics}, number = {SUPPL 1}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1367-4803}, doi = {10.1093/bioinformatics/btac223}, pages = {153 -- 160}, year = {2022}, abstract = {Motivation: Nanopore sequencers allow targeted sequencing of interesting nucleotide sequences by rejecting other sequences from individual pores. This feature facilitates the enrichment of low-abundant sequences by depleting overrepresented ones in-silico. Existing tools for adaptive sampling either apply signal alignment, which cannot handle human-sized reference sequences, or apply read mapping in sequence space relying on fast graphical processing units (GPU) base callers for real-time read rejection. Using nanopore long-read mapping tools is also not optimal when mapping shorter reads as usually analyzed in adaptive sampling applications. Results: Here, we present a new approach for nanopore adaptive sampling that combines fast CPU and GPU base calling with read classification based on Interleaved Bloom Filters. ReadBouncer improves the potential enrichment of low abundance sequences by its high read classification sensitivity and specificity, outperforming existing tools in the field. It robustly removes even reads belonging to large reference sequences while running on commodity hardware without GPUs, making adaptive sampling accessible for in-field researchers. Readbouncer also provides a user-friendly interface and installer files for end-users without a bioinformatics background.}, language = {en} } @misc{UllrichEnkeTeichmannetal.2019, author = {Ullrich, Andre and Enke, Judith and Teichmann, Malte and Kress, Antonio and Gronau, Norbert}, title = {Audit - and then what?}, series = {Procedia Manufacturing}, volume = {31}, journal = {Procedia Manufacturing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2351-9789}, doi = {10.1016/j.promfg.2019.03.025}, pages = {162 -- 168}, year = {2019}, abstract = {Current trends such as digital transformation, Internet of Things, or Industry 4.0 are challenging the majority of learning factories. Regardless of whether a conventional learning factory, a model factory, or a digital learning factory, traditional approaches such as the monotonous execution of specific instructions don't suffice the learner's needs, market requirements as well as especially current technological developments. Contemporary teaching environments need a clear strategy, a road to follow for being able to successfully cope with the changes and develop towards digitized learning factories. This demand driven necessity of transformation leads to another obstacle: Assessing the status quo and developing and implementing adequate action plans. Within this paper, details of a maturity-based audit of the hybrid learning factory in the Research and Application Centre Industry 4.0 and a thereof derived roadmap for the digitization of a learning factory are presented.}, language = {en} } @article{TrillaDrimallaBajboujetal.2020, author = {Trilla, Irene and Drimalla, Hanna and Bajbouj, Malek and Dziobek, Isabel}, title = {The influence of reward on facial mimicry}, series = {Frontiers in behavioral neuroscience}, volume = {14}, journal = {Frontiers in behavioral neuroscience}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1662-5153}, doi = {10.3389/fnbeh.2020.00088}, pages = {12}, year = {2020}, abstract = {Recent findings suggest a role of oxytocin on the tendency to spontaneously mimic the emotional facial expressions of others. Oxytocin-related increases of facial mimicry, however, seem to be dependent on contextual factors. Given previous literature showing that people preferentially mimic emotional expressions of individuals associated with high (vs. low) rewards, we examined whether the reward value of the mimicked agent is one factor influencing the oxytocin effects on facial mimicry. To test this hypothesis, 60 male adults received 24 IU of either intranasal oxytocin or placebo in a double-blind, between-subject experiment. Next, the value of male neutral faces was manipulated using an associative learning task with monetary rewards. After the reward associations were learned, participants watched videos of the same faces displaying happy and angry expressions. Facial reactions to the emotional expressions were measured with electromyography. We found that participants judged as more pleasant the face identities associated with high reward values than with low reward values. However, happy expressions by low rewarding faces were more spontaneously mimicked than high rewarding faces. Contrary to our expectations, we did not find a significant direct effect of intranasal oxytocin on facial mimicry, nor on the reward-driven modulation of mimicry. Our results support the notion that mimicry is a complex process that depends on contextual factors, but failed to provide conclusive evidence of a role of oxytocin on the modulation of facial mimicry.}, language = {en} } @article{TrautmannZhouBrahmsetal.2021, author = {Trautmann, Justin and Zhou, Lin and Brahms, Clemens Markus and Tunca, Can and Ersoy, Cem and Granacher, Urs and Arnrich, Bert}, title = {TRIPOD}, series = {Data : open access ʻData in scienceʼ journal}, volume = {6}, journal = {Data : open access ʻData in scienceʼ journal}, number = {9}, publisher = {MDPI}, address = {Basel}, issn = {2306-5729}, doi = {10.3390/data6090095}, pages = {19}, year = {2021}, abstract = {Inertial measurement units (IMUs) enable easy to operate and low-cost data recording for gait analysis. When combined with treadmill walking, a large number of steps can be collected in a controlled environment without the need of a dedicated gait analysis laboratory. In order to evaluate existing and novel IMU-based gait analysis algorithms for treadmill walking, a reference dataset that includes IMU data as well as reliable ground truth measurements for multiple participants and walking speeds is needed. This article provides a reference dataset consisting of 15 healthy young adults who walked on a treadmill at three different speeds. Data were acquired using seven IMUs placed on the lower body, two different reference systems (Zebris FDMT-HQ and OptoGait), and two RGB cameras. Additionally, in order to validate an existing IMU-based gait analysis algorithm using the dataset, an adaptable modular data analysis pipeline was built. Our results show agreement between the pressure-sensitive Zebris and the photoelectric OptoGait system (r = 0.99), demonstrating the quality of our reference data. As a use case, the performance of an algorithm originally designed for overground walking was tested on treadmill data using the data pipeline. The accuracy of stride length and stride time estimations was comparable to that reported in other studies with overground data, indicating that the algorithm is equally applicable to treadmill data. The Python source code of the data pipeline is publicly available, and the dataset will be provided by the authors upon request, enabling future evaluations of IMU gait analysis algorithms without the need of recording new data.}, language = {en} } @misc{TorkuraSukmanaStraussetal.2018, author = {Torkura, Kennedy A. and Sukmana, Muhammad Ihsan Haikal and Strauss, Tim and Graupner, Hendrik and Cheng, Feng and Meinel, Christoph}, title = {CSBAuditor}, series = {17th International Symposium on Network Computing and Applications (NCA)}, journal = {17th International Symposium on Network Computing and Applications (NCA)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-7659-2}, doi = {10.1109/NCA.2018.8548329}, pages = {10}, year = {2018}, abstract = {Cloud Storage Brokers (CSB) provide seamless and concurrent access to multiple Cloud Storage Services (CSS) while abstracting cloud complexities from end-users. However, this multi-cloud strategy faces several security challenges including enlarged attack surfaces, malicious insider threats, security complexities due to integration of disparate components and API interoperability issues. Novel security approaches are imperative to tackle these security issues. Therefore, this paper proposes CSBAuditor, a novel cloud security system that continuously audits CSB resources, to detect malicious activities and unauthorized changes e.g. bucket policy misconfigurations, and remediates these anomalies. The cloud state is maintained via a continuous snapshotting mechanism thereby ensuring fault tolerance. We adopt the principles of chaos engineering by integrating Broker Monkey, a component that continuously injects failure into our reference CSB system, Cloud RAID. Hence, CSBAuditor is continuously tested for efficiency i.e. its ability to detect the changes injected by Broker Monkey. CSBAuditor employs security metrics for risk analysis by computing severity scores for detected vulnerabilities using the Common Configuration Scoring System, thereby overcoming the limitation of insufficient security metrics in existing cloud auditing schemes. CSBAuditor has been tested using various strategies including chaos engineering failure injection strategies. Our experimental evaluation validates the efficiency of our approach against the aforementioned security issues with a detection and recovery rate of over 96 \%.}, language = {en} } @misc{TorkuraSukmanaMeinigetal.2018, author = {Torkura, Kennedy A. and Sukmana, Muhammad Ihsan Haikal and Meinig, Michael and Kayem, Anne V. D. M. and Cheng, Feng and Meinel, Christoph and Graupner, Hendrik}, title = {Securing cloud storage brokerage systems through threat models}, series = {Proceedings IEEE 32nd International Conference on Advanced Information Networking and Applications (AINA)}, journal = {Proceedings IEEE 32nd International Conference on Advanced Information Networking and Applications (AINA)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-2195-0}, issn = {1550-445X}, doi = {10.1109/AINA.2018.00114}, pages = {759 -- 768}, year = {2018}, abstract = {Cloud storage brokerage is an abstraction aimed at providing value-added services. However, Cloud Service Brokers are challenged by several security issues including enlarged attack surfaces due to integration of disparate components and API interoperability issues. Therefore, appropriate security risk assessment methods are required to identify and evaluate these security issues, and examine the efficiency of countermeasures. A possible approach for satisfying these requirements is employment of threat modeling concepts, which have been successfully applied in traditional paradigms. In this work, we employ threat models including attack trees, attack graphs and Data Flow Diagrams against a Cloud Service Broker (CloudRAID) and analyze these security threats and risks. Furthermore, we propose an innovative technique for combining Common Vulnerability Scoring System (CVSS) and Common Configuration Scoring System (CCSS) base scores in probabilistic attack graphs to cater for configuration-based vulnerabilities which are typically leveraged for attacking cloud storage systems. This approach is necessary since existing schemes do not provide sufficient security metrics, which are imperatives for comprehensive risk assessments. We demonstrate the efficiency of our proposal by devising CCSS base scores for two common attacks against cloud storage: Cloud Storage Enumeration Attack and Cloud Storage Exploitation Attack. These metrics are then used in Attack Graph Metric-based risk assessment. Our experimental evaluation shows that our approach caters for the aforementioned gaps and provides efficient security hardening options. Therefore, our proposals can be employed to improve cloud security.}, language = {en} } @misc{TorkuraSukmanaKayemetal.2018, author = {Torkura, Kennedy A. and Sukmana, Muhammad Ihsan Haikal and Kayem, Anne V. D. M. and Cheng, Feng and Meinel, Christoph}, title = {A cyber risk based moving target defense mechanism for microservice architectures}, series = {IEEE Intl Conf on Parallel \& Distributed Processing with Applications, Ubiquitous Computing \& Communications, Big Data \& Cloud Computing, Social Computing \& Networking, Sustainable Computing \& Communications (ISPA/IUCC/BDCloud/SocialCom/SustainCom)}, journal = {IEEE Intl Conf on Parallel \& Distributed Processing with Applications, Ubiquitous Computing \& Communications, Big Data \& Cloud Computing, Social Computing \& Networking, Sustainable Computing \& Communications (ISPA/IUCC/BDCloud/SocialCom/SustainCom)}, publisher = {Institute of Electrical and Electronics Engineers}, address = {Los Alamitos}, isbn = {978-1-7281-1141-4}, issn = {2158-9178}, doi = {10.1109/BDCloud.2018.00137}, pages = {932 -- 939}, year = {2018}, abstract = {Microservice Architectures (MSA) structure applications as a collection of loosely coupled services that implement business capabilities. The key advantages of MSA include inherent support for continuous deployment of large complex applications, agility and enhanced productivity. However, studies indicate that most MSA are homogeneous, and introduce shared vulnerabilites, thus vulnerable to multi-step attacks, which are economics-of-scale incentives to attackers. In this paper, we address the issue of shared vulnerabilities in microservices with a novel solution based on the concept of Moving Target Defenses (MTD). Our mechanism works by performing risk analysis against microservices to detect and prioritize vulnerabilities. Thereafter, security risk-oriented software diversification is employed, guided by a defined diversification index. The diversification is performed at runtime, leveraging both model and template based automatic code generation techniques to automatically transform programming languages and container images of the microservices. Consequently, the microservices attack surfaces are altered thereby introducing uncertainty for attackers while reducing the attackability of the microservices. Our experiments demonstrate the efficiency of our solution, with an average success rate of over 70\% attack surface randomization.}, language = {en} } @article{ThienenWeinsteinMeinel2023, author = {Thienen, Julia von and Weinstein, Theresa Julia and Meinel, Christoph}, title = {Creative metacognition in design thinking}, series = {Frontiers in psychology}, volume = {14}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2023.1157001}, pages = {20}, year = {2023}, abstract = {Design thinking is a well-established practical and educational approach to fostering high-level creativity and innovation, which has been refined since the 1950s with the participation of experts like Joy Paul Guilford and Abraham Maslow. Through real-world projects, trainees learn to optimize their creative outcomes by developing and practicing creative cognition and metacognition. This paper provides a holistic perspective on creativity, enabling the formulation of a comprehensive theoretical framework of creative metacognition. It focuses on the design thinking approach to creativity and explores the role of metacognition in four areas of creativity expertise: Products, Processes, People, and Places. The analysis includes task-outcome relationships (product metacognition), the monitoring of strategy effectiveness (process metacognition), an understanding of individual or group strengths and weaknesses (people metacognition), and an examination of the mutual impact between environments and creativity (place metacognition). It also reviews measures taken in design thinking education, including a distribution of cognition and metacognition, to support students in their development of creative mastery. On these grounds, we propose extended methods for measuring creative metacognition with the goal of enhancing comprehensive assessments of the phenomenon. Proposed methodological advancements include accuracy sub-scales, experimental tasks where examinees explore problem and solution spaces, combinations of naturalistic observations with capability testing, as well as physiological assessments as indirect measures of creative metacognition.}, language = {en} } @article{ThienenClanceyCorazzaetal.2018, author = {Thienen, Julia von and Clancey, William J. and Corazza, Giovanni Emanuele and Meinel, Christoph}, title = {Theoretical foundations of design thinking creative thinking theories}, series = {Design Thinking Research: Making Distinctions: Collaboration versus Cooperation}, journal = {Design Thinking Research: Making Distinctions: Collaboration versus Cooperation}, publisher = {Springer}, address = {New York}, isbn = {978-3-319-60967-6}, doi = {10.1007/978-3-319-60967-6_2}, pages = {13 -- 40}, year = {2018}, abstract = {Design thinking is acknowledged as a thriving innovation practice plus something more, something in the line of a deep understanding of innovation processes. At the same time, quite how and why design thinking works-in scientific terms-appeared an open question at first. Over recent years, empirical research has achieved great progress in illuminating the principles that make design thinking successful. Lately, the community began to explore an additional approach. Rather than setting up novel studies, investigations into the history of design thinking hold the promise of adding systematically to our comprehension of basic principles. This chapter makes a start in revisiting design thinking history with the aim of explicating scientific understandings that inform design thinking practices today. It offers a summary of creative thinking theories that were brought to Stanford Engineering in the 1950s by John E. Arnold.}, language = {en} } @misc{TeusnerMatthiesStaubitz2018, author = {Teusner, Ralf and Matthies, Christoph and Staubitz, Thomas}, title = {What Stays in Mind?}, series = {IEEE Frontiers in Education Conference (FIE)}, journal = {IEEE Frontiers in Education Conference (FIE)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-1174-6}, issn = {0190-5848}, doi = {10.1109/FIE.2018.8658890}, pages = {9}, year = {2018}, language = {en} } @misc{TeichmannUllrichGronau2019, author = {Teichmann, Malte and Ullrich, Andre and Gronau, Norbert}, title = {Subject-oriented learning}, series = {Procedia Manufacturing}, volume = {31}, journal = {Procedia Manufacturing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2351-9789}, doi = {10.1016/j.promfg.2019.03.012}, pages = {72 -- 78}, year = {2019}, abstract = {The transformation to a digitized company changes not only the work but also social context for the employees and requires inter alia new knowledge and skills from them. Additionally, individual action problems arise. This contribution proposes the subject-oriented learning theory, in which the employees´ action problems are the starting point of training activities in learning factories. In this contribution, the subject-oriented learning theory is exemplified and respective advantages for vocational training in learning factories are pointed out both theoretically and practically. Thereby, especially the individual action problems of learners and the infrastructure are emphasized as starting point for learning processes and competence development.}, language = {en} } @article{TangNakamotoSternetal.2022, author = {Tang, Mitchell and Nakamoto, Carter H. and Stern, Ariel Dora and Mehrotra, Ateev}, title = {Trends in remote patient monitoring use in traditional Medicare}, series = {JAMA Internal Medicine}, volume = {182}, journal = {JAMA Internal Medicine}, number = {9}, publisher = {American Veterinary Medical Association}, address = {Chicago}, issn = {2168-6106}, doi = {10.1001/jamainternmed.2022.3043}, pages = {1005 -- 1006}, year = {2022}, abstract = {This cross-sectional study uses traditional Medicare claims data to assess trends in general remote patient monitoring from January 2018 through September 2021.}, language = {en} } @misc{TalaSchrapeKrstićetal.2018, author = {Tala, Mahdi and Schrape, Oliver and Krstić, Miloš and Bertozzi, Davide}, title = {Exploring the Performance-Energy Optimization Space of a Bridge Between 3D-Stacked Electronic and Optical Networks-on-Chip}, series = {XXXIII Conference on Design of Circuits and Integrated Systems (DCIS)}, journal = {XXXIII Conference on Design of Circuits and Integrated Systems (DCIS)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-7281-0171-2}, issn = {2471-6170}, doi = {10.1109/DCIS.2018.8681461}, pages = {6}, year = {2018}, abstract = {The relentless improvement of silicon photonics is making optical interconnects and networks appealing for use in miniaturized systems, where electrical interconnects cannot keep up with the growing levels of core integration due to bandwidth density and power efficiency limitations. At the same time, solutions such as 3D stacking or 2.5D integration open the door to a fully dedicated process optimization for the photonic die. However, an architecture-level integration challenge arises between the electronic network and the optical one in such tightly-integrated parallel systems. It consists of adapting signaling rates, matching the different levels of communication parallelism, handling cross-domain flow control, addressing re-synchronization concerns, and avoiding protocol-dependent deadlock. The associated energy and performance overhead may offset the inherent benefits of the emerging technology itself. This paper explores a hybrid CMOS-ECL bridge architecture between 3D-stacked technology-heterogeneous networks-on-chip (NoCs). The different ways of overcoming the serialization challenge (i.e., through an improvement of the signaling rate and/or through space-/wavelength division multiplexing options) give rise to a configuration space that the paper explores, in search for the most energy-efficient configuration for high-performance.}, language = {en} } @article{SoechtingTrapp2020, author = {S{\"o}chting, Maximilian and Trapp, Matthias}, title = {Controlling image-stylization techniques using eye tracking}, series = {Science and Technology Publications}, journal = {Science and Technology Publications}, publisher = {Springer}, address = {Berlin}, issn = {2184-4321}, pages = {10}, year = {2020}, abstract = {With the spread of smart phones capable of taking high-resolution photos and the development of high-speed mobile data infrastructure, digital visual media is becoming one of the most important forms of modern communication. With this development, however, also comes a devaluation of images as a media form with the focus becoming the frequency at which visual content is generated instead of the quality of the content. In this work, an interactive system using image-abstraction techniques and an eye tracking sensor is presented, which allows users to experience diverting and dynamic artworks that react to their eye movement. The underlying modular architecture enables a variety of different interaction techniques that share common design principles, making the interface as intuitive as possible. The resulting experience allows users to experience a game-like interaction in which they aim for a reward, the artwork, while being held under constraints, e.g., not blinking. The co nscious eye movements that are required by some interaction techniques hint an interesting, possible future extension for this work into the field of relaxation exercises and concentration training.}, language = {en} } @misc{SukmanaTorkuraChengetal.2018, author = {Sukmana, Muhammad Ihsan Haikal and Torkura, Kennedy A. and Cheng, Feng and Meinel, Christoph and Graupner, Hendrik}, title = {Unified logging system for monitoring multiple cloud storage providers in cloud storage broker}, series = {32ND International Conference on Information Networking (ICOIN)}, journal = {32ND International Conference on Information Networking (ICOIN)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-2290-2}, doi = {10.1109/ICOIN.2018.8343081}, pages = {44 -- 49}, year = {2018}, abstract = {With the increasing demand for personal and enterprise data storage service, Cloud Storage Broker (CSB) provides cloud storage service using multiple Cloud Service Providers (CSPs) with guaranteed Quality of Service (QoS), such as data availability and security. However monitoring cloud storage usage in multiple CSPs has become a challenge for CSB due to lack of standardized logging format for cloud services that causes each CSP to implement its own format. In this paper we propose a unified logging system that can be used by CSB to monitor cloud storage usage across multiple CSPs. We gather cloud storage log files from three different CSPs and normalise these into our proposed log format that can be used for further analysis process. We show that our work enables a coherent view suitable for data navigation, monitoring, and analytics.}, language = {en} } @article{StojanovicTrappRichteretal.2019, author = {Stojanovic, Vladeta and Trapp, Matthias and Richter, Rico and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {Service-oriented semantic enrichment of indoor point clouds using octree-based multiview classification}, series = {Graphical Models}, volume = {105}, journal = {Graphical Models}, publisher = {Elsevier}, address = {San Diego}, issn = {1524-0703}, doi = {10.1016/j.gmod.2019.101039}, pages = {18}, year = {2019}, abstract = {The use of Building Information Modeling (BIM) for Facility Management (FM) in the Operation and Maintenance (O\&M) stages of the building life-cycle is intended to bridge the gap between operations and digital data, but lacks the functionality of assessing the state of the built environment due to non-automated generation of associated semantics. 3D point clouds can be used to capture the physical state of the built environment, but also lack these associated semantics. A prototypical implementation of a service-oriented architecture for classification of indoor point cloud scenes of office environments is presented, using multiview classification. The multiview classification approach is tested using a retrained Convolutional Neural Network (CNN) model - Inception V3. The presented approach for classifying common office furniture objects (chairs, sofas and desks), contained in 3D point cloud scans, is tested and evaluated. The results show that the presented approach can classify common office furniture up to an acceptable degree of accuracy, and is suitable for quick and robust semantics approximation - based on RGB (red, green and blue color channel) cubemap images of the octree partitioned areas of the 3D point cloud scan. Additional methods for web-based 3D visualization, editing and annotation of point clouds are also discussed. Using the described approach, captured scans of indoor environments can be semantically enriched using object annotations derived from multiview classification results. Furthermore, the presented approach is suited for semantic enrichment of lower resolution indoor point clouds acquired using commodity mobile devices.}, language = {en} } @misc{StaubitzTeusnerMeinel2019, author = {Staubitz, Thomas and Teusner, Ralf and Meinel, Christoph}, title = {MOOCs in Secondary Education}, series = {2019 IEEE Global Engineering Education Conference (EDUCON)}, journal = {2019 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-9506-7}, issn = {2165-9567}, doi = {10.1109/EDUCON.2019.8725138}, pages = {173 -- 182}, year = {2019}, abstract = {Computer science education in German schools is often less than optimal. It is only mandatory in a few of the federal states and there is a lack of qualified teachers. As a MOOC (Massive Open Online Course) provider with a German background, we developed the idea to implement a MOOC addressing pupils in secondary schools to fill this gap. The course targeted high school pupils and enabled them to learn the Python programming language. In 2014, we successfully conducted the first iteration of this MOOC with more than 7000 participants. However, the share of pupils in the course was not quite satisfactory. So we conducted several workshops with teachers to find out why they had not used the course to the extent that we had imagined. The paper at hand explores and discusses the steps we have taken in the following years as a result of these workshops.}, language = {en} } @misc{StaubitzMeinel2019, author = {Staubitz, Thomas and Meinel, Christoph}, title = {Graded Team Assignments in MOOCs}, series = {SCALE}, journal = {SCALE}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6804-9}, doi = {10.1145/3330430.3333619}, pages = {10}, year = {2019}, abstract = {The ability to work in teams is an important skill in today's work environments. In MOOCs, however, team work, team tasks, and graded team-based assignments play only a marginal role. To close this gap, we have been exploring ways to integrate graded team-based assignments in MOOCs. Some goals of our work are to determine simple criteria to match teams in a volatile environment and to enable a frictionless online collaboration for the participants within our MOOC platform. The high dropout rates in MOOCs pose particular challenges for team work in this context. By now, we have conducted 15 MOOCs containing graded team-based assignments in a variety of topics. The paper at hand presents a study that aims to establish a solid understanding of the participants in the team tasks. Furthermore, we attempt to determine which team compositions are particularly successful. Finally, we examine how several modifications to our platform's collaborative toolset have affected the dropout rates and performance of the teams.}, language = {en} } @misc{StaubitzMeinel2018, author = {Staubitz, Thomas and Meinel, Christoph}, title = {Collaborative Learning in MOOCs - Approaches and Experiments}, series = {2018 IEEE Frontiers in Education (FIE) Conference}, journal = {2018 IEEE Frontiers in Education (FIE) Conference}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-1174-6}, issn = {0190-5848}, pages = {9}, year = {2018}, abstract = {This Research-to-Practice paper examines the practical application of various forms of collaborative learning in MOOCs. Since 2012, about 60 MOOCs in the wider context of Information Technology and Computer Science have been conducted on our self-developed MOOC platform. The platform is also used by several customers, who either run their own platform instances or use our white label platform. We, as well as some of our partners, have experimented with different approaches in collaborative learning in these courses. Based on the results of early experiments, surveys amongst our participants, and requests by our business partners we have integrated several options to offer forms of collaborative learning to the system. The results of our experiments are directly fed back to the platform development, allowing to fine tune existing and to add new tools where necessary. In the paper at hand, we discuss the benefits and disadvantages of decisions in the design of a MOOC with regard to the various forms of collaborative learning. While the focus of the paper at hand is on forms of large group collaboration, two types of small group collaboration on our platforms are briefly introduced.}, language = {en} } @misc{SianiparSukmanaMeinel2019, author = {Sianipar, Johannes Harungguan and Sukmana, Muhammad Ihsan Haikal and Meinel, Christoph}, title = {Moving sensitive data against live memory dumping, spectre and meltdown attacks}, series = {26th International Conference on Systems Engineering (ICSEng)}, journal = {26th International Conference on Systems Engineering (ICSEng)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-7834-3}, pages = {8}, year = {2019}, abstract = {The emergence of cloud computing allows users to easily host their Virtual Machines with no up-front investment and the guarantee of always available anytime anywhere. But with the Virtual Machine (VM) is hosted outside of user's premise, the user loses the physical control of the VM as it could be running on untrusted host machines in the cloud. Malicious host administrator could launch live memory dumping, Spectre, or Meltdown attacks in order to extract sensitive information from the VM's memory, e.g. passwords or cryptographic keys of applications running in the VM. In this paper, inspired by the moving target defense (MTD) scheme, we propose a novel approach to increase the security of application's sensitive data in the VM by continuously moving the sensitive data among several memory allocations (blocks) in Random Access Memory (RAM). A movement function is added into the application source code in order for the function to be running concurrently with the application's main function. Our approach could reduce the possibility of VM's sensitive data in the memory to be leaked into memory dump file by 2 5\% and secure the sensitive data from Spectre and Meltdown attacks. Our approach's overhead depends on the number and the size of the sensitive data.}, language = {en} } @article{ShiSchirneckFriedrichetal.2018, author = {Shi, Feng and Schirneck, Friedrich Martin and Friedrich, Tobias and K{\"o}tzing, Timo and Neumann, Frank}, title = {Reoptimization time analysis of evolutionary algorithms on linear functions under dynamic uniform constraints}, series = {Algorithmica : an international journal in computer science}, volume = {82}, journal = {Algorithmica : an international journal in computer science}, number = {10}, publisher = {Springer}, address = {New York}, issn = {0178-4617}, doi = {10.1007/s00453-020-00739-x}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-605295}, pages = {3117 -- 3123}, year = {2018}, abstract = {Rigorous runtime analysis is a major approach towards understanding evolutionary computing techniques, and in this area linear pseudo-Boolean objective functions play a central role. Having an additional linear constraint is then equivalent to the NP-hard Knapsack problem, certain classes thereof have been studied in recent works. In this article, we present a dynamic model of optimizing linear functions under uniform constraints. Starting from an optimal solution with respect to a given constraint bound, we investigate the runtimes that different evolutionary algorithms need to recompute an optimal solution when the constraint bound changes by a certain amount. The classical (1+1) EA and several population-based algorithms are designed for that purpose, and are shown to recompute efficiently. Furthermore, a variant of the (1+(λ,λ))GA for the dynamic optimization problem is studied, whose performance is better when the change of the constraint bound is small.}, language = {en} } @misc{ShaabaniMeinel2018, author = {Shaabani, Nuhad and Meinel, Christoph}, title = {Improving the efficiency of inclusion dependency detection}, series = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, journal = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6014-2}, doi = {10.1145/3269206.3271724}, pages = {207 -- 216}, year = {2018}, abstract = {The detection of all inclusion dependencies (INDs) in an unknown dataset is at the core of any data profiling effort. Apart from the discovery of foreign key relationships, INDs can help perform data integration, integrity checking, schema (re-)design, and query optimization. With the advent of Big Data, the demand increases for efficient INDs discovery algorithms that can scale with the input data size. To this end, we propose S-INDD++ as a scalable system for detecting unary INDs in large datasets. S-INDD++ applies a new stepwise partitioning technique that helps discard a large number of attributes in early phases of the detection by processing the first partitions of smaller sizes. S-INDD++ also extends the concept of the attribute clustering to decide which attributes to be discarded based on the clustering result of each partition. Moreover, in contrast to the state-of-the-art, S-INDD++ does not require the partition to fit into the main memory-which is a highly appreciable property in the face of the ever growing datasets. We conducted an exhaustive evaluation of S-INDD++ by applying it to large datasets with thousands attributes and more than 266 million tuples. The results show the high superiority of S-INDD++ over the state-of-the-art. S-INDD++ reduced up to 50 \% of the runtime in comparison with BINDER, and up to 98 \% in comparison with S-INDD.}, language = {en} } @article{SerthStaubitzvanEltenetal.2022, author = {Serth, Sebastian and Staubitz, Thomas and van Elten, Martin and Meinel, Christoph}, title = {Measuring the effects of course modularizations in online courses for life-long learners}, series = {Frontiers in Education}, volume = {7}, journal = {Frontiers in Education}, editor = {Gamage, Dilrukshi}, publisher = {Frontiers}, address = {Lausanne, Schweiz}, issn = {2504-284X}, doi = {10.3389/feduc.2022.1008545}, pages = {15}, year = {2022}, abstract = {Many participants in Massive Open Online Courses are full-time employees seeking greater flexibility in their time commitment and the available learning paths. We recently addressed these requirements by splitting up our 6-week courses into three 2-week modules followed by a separate exam. Modularizing courses offers many advantages: Shorter modules are more sustainable and can be combined, reused, and incorporated into learning paths more easily. Time flexibility for learners is also improved as exams can now be offered multiple times per year, while the learning content is available independently. In this article, we answer the question of which impact this modularization has on key learning metrics, such as course completion rates, learning success, and no-show rates. Furthermore, we investigate the influence of longer breaks between modules on these metrics. According to our analysis, course modules facilitate more selective learning behaviors that encourage learners to focus on topics they are the most interested in. At the same time, participation in overarching exams across all modules seems to be less appealing compared to an integrated exam of a 6-week course. While breaks between the modules increase the distinctive appearance of individual modules, a break before the final exam further reduces initial interest in the exams. We further reveal that participation in self-paced courses as a preparation for the final exam is unlikely to attract new learners to the course offerings, even though learners' performance is comparable to instructor-paced courses. The results of our long-term study on course modularization provide a solid foundation for future research and enable educators to make informed decisions about the design of their courses.}, language = {en} } @article{SchneiderMaximovaSakizloglouetal.2021, author = {Schneider, Sven and Maximova, Maria and Sakizloglou, Lucas and Giese, Holger}, title = {Formal testing of timed graph transformation systems using metric temporal graph logic}, series = {International journal on software tools for technology transfer}, volume = {23}, journal = {International journal on software tools for technology transfer}, number = {3}, publisher = {Springer}, address = {Heidelberg}, issn = {1433-2779}, doi = {10.1007/s10009-020-00585-w}, pages = {411 -- 488}, year = {2021}, abstract = {Embedded real-time systems generate state sequences where time elapses between state changes. Ensuring that such systems adhere to a provided specification of admissible or desired behavior is essential. Formal model-based testing is often a suitable cost-effective approach. We introduce an extended version of the formalism of symbolic graphs, which encompasses types as well as attributes, for representing states of dynamic systems. Relying on this extension of symbolic graphs, we present a novel formalism of timed graph transformation systems (TGTSs) that supports the model-based development of dynamic real-time systems at an abstract level where possible state changes and delays are specified by graph transformation rules. We then introduce an extended form of the metric temporal graph logic (MTGL) with increased expressiveness to improve the applicability of MTGL for the specification of timed graph sequences generated by a TGTS. Based on the metric temporal operators of MTGL and its built-in graph binding mechanics, we express properties on the structure and attributes of graphs as well as on the occurrence of graphs over time that are related by their inner structure. We provide formal support for checking whether a single generated timed graph sequence adheres to a provided MTGL specification. Relying on this logical foundation, we develop a testing framework for TGTSs that are specified using MTGL. Lastly, we apply this testing framework to a running example by using our prototypical implementation in the tool AutoGraph.}, language = {en} } @article{SchlosserWaltherBoissieretal.2019, author = {Schlosser, Rainer and Walther, Carsten and Boissier, Martin and Uflacker, Matthias}, title = {Automated repricing and ordering strategies in competitive markets}, series = {AI communications : AICOM ; the European journal on artificial intelligence}, volume = {32}, journal = {AI communications : AICOM ; the European journal on artificial intelligence}, number = {1}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0921-7126}, doi = {10.3233/AIC-180603}, pages = {15 -- 29}, year = {2019}, abstract = {Merchants on modern e-commerce platforms face a highly competitive environment. They compete against each other using automated dynamic pricing and ordering strategies. Successfully managing both inventory levels as well as offer prices is a challenging task as (i) demand is uncertain, (ii) competitors strategically interact, and (iii) optimized pricing and ordering decisions are mutually dependent. We show how to derive optimized data-driven pricing and ordering strategies which are based on demand learning techniques and efficient dynamic optimization models. We verify the superior performance of our self-adaptive strategies by comparing them to different rule-based as well as data-driven strategies in duopoly and oligopoly settings. Further, to study and to optimize joint dynamic ordering and pricing strategies on online marketplaces, we built an interactive simulation platform. To be both flexible and scalable, the platform has a microservice-based architecture and allows handling dozens of competing merchants and streams of consumers with configurable characteristics.}, language = {en} } @article{SchlosserRichly2019, author = {Schlosser, Rainer and Richly, Keven}, title = {Dynamic pricing under competition with data-driven price anticipations and endogenous reference price effects}, series = {Journal of revenue and pricing management}, volume = {18}, journal = {Journal of revenue and pricing management}, number = {6}, publisher = {Palgrave Macmillan}, address = {Basingstoke}, issn = {1476-6930}, doi = {10.1057/s41272-019-00206-5}, pages = {451 -- 464}, year = {2019}, abstract = {Online markets have become highly dynamic and competitive. Many sellers use automated data-driven strategies to estimate demand and to update prices frequently. Further, notification services offered by marketplaces allow to continuously track markets and to react to competitors' price adjustments instantaneously. To derive successful automated repricing strategies is challenging as competitors' strategies are typically not known. In this paper, we analyze automated repricing strategies with data-driven price anticipations under duopoly competition. In addition, we account for reference price effects in demand, which are affected by the price adjustments of both competitors. We show how to derive optimized self-adaptive pricing strategies that anticipate price reactions of the competitor and take the evolution of the reference price into account. We verify that the results of our adaptive learning strategy tend to optimal solutions, which can be derived for scenarios with full information. Finally, we analyze the case in which our learning strategy is played against itself. We find that our self-adaptive strategies can be used to approximate equilibria in mixed strategies.}, language = {en} } @misc{SchlosserKossmannBoissier2019, author = {Schlosser, Rainer and Kossmann, Jan and Boissier, Martin}, title = {Efficient Scalable Multi-Attribute Index Selection Using Recursive Strategies}, series = {2019 IEEE 35th International Conference on Data Engineering (ICDE)}, journal = {2019 IEEE 35th International Conference on Data Engineering (ICDE)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-7474-1}, issn = {1084-4627}, doi = {10.1109/ICDE.2019.00113}, pages = {1238 -- 1249}, year = {2019}, abstract = {An efficient selection of indexes is indispensable for database performance. For large problem instances with hundreds of tables, existing approaches are not suitable: They either exhibit prohibitive runtimes or yield far from optimal index configurations by strongly limiting the set of index candidates or not handling index interaction explicitly. We introduce a novel recursive strategy that does not exclude index candidates in advance and effectively accounts for index interaction. Using large real-world workloads, we demonstrate the applicability of our approach. Further, we evaluate our solution end to end with a commercial database system using a reproducible setup. We show that our solutions are near-optimal for small index selection problems. For larger problems, our strategy outperforms state-of-the-art approaches in both scalability and solution quality.}, language = {en} } @article{SchlosserChenavazDimitrov2021, author = {Schlosser, Rainer and Chenavaz, R{\´e}gis Y. and Dimitrov, Stanko}, title = {Circular economy}, series = {International journal of production economics}, volume = {236}, journal = {International journal of production economics}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0925-5273}, doi = {10.1016/j.ijpe.2021.108117}, pages = {13}, year = {2021}, abstract = {In a circular economy, the use of recycled resources in production is a key performance indicator for management. Yet, academic studies are still unable to inform managers on appropriate recycling and pricing policies. We develop an optimal control model integrating a firm's recycling rate, which can use both virgin and recycled resources in the production process. Our model accounts for recycling influence both at the supply- and demandsides. The positive effect of a firm's use of recycled resources diminishes over time but may increase through investments. Using general formulations for demand and cost, we analytically examine joint dynamic pricing and recycling investment policies in order to determine their optimal interplay over time. We provide numerical experiments to assess the existence of a steady-state and to calculate sensitivity analyses with respect to various model parameters. The analysis shows how to dynamically adapt jointly optimized controls to reach sustainability in the production process. Our results pave the way to sounder sustainable practices for firms operating within a circular economy.}, language = {en} } @article{SchlosserBoissier2018, author = {Schlosser, Rainer and Boissier, Martin}, title = {Dealing with the dimensionality curse in dynamic pricing competition}, series = {Computers \& Operations Research}, volume = {100}, journal = {Computers \& Operations Research}, publisher = {Elsevier}, address = {Oxford}, issn = {0305-0548}, doi = {10.1016/j.cor.2018.07.011}, pages = {26 -- 42}, year = {2018}, abstract = {Most sales applications are characterized by competition and limited demand information. For successful pricing strategies, frequent price adjustments as well as anticipation of market dynamics are crucial. Both effects are challenging as competitive markets are complex and computations of optimized pricing adjustments can be time-consuming. We analyze stochastic dynamic pricing models under oligopoly competition for the sale of perishable goods. To circumvent the curse of dimensionality, we propose a heuristic approach to efficiently compute price adjustments. To demonstrate our strategy's applicability even if the number of competitors is large and their strategies are unknown, we consider different competitive settings in which competitors frequently and strategically adjust their prices. For all settings, we verify that our heuristic strategy yields promising results. We compare the performance of our heuristic against upper bounds, which are obtained by optimal strategies that take advantage of perfect price anticipations. We find that price adjustment frequencies can have a larger impact on expected profits than price anticipations. Finally, our approach has been applied on Amazon for the sale of used books. We have used a seller's historical market data to calibrate our model. Sales results show that our data-driven strategy outperforms the rule-based strategy of an experienced seller by a profit increase of more than 20\%.}, language = {en} } @article{Schlosser2016, author = {Schlosser, Rainer}, title = {Stochastic dynamic pricing and advertising in isoelastic oligopoly models}, series = {European Journal of Operational Research}, volume = {259}, journal = {European Journal of Operational Research}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0377-2217}, doi = {10.1016/j.ejor.2016.11.021}, pages = {1144 -- 1155}, year = {2016}, abstract = {In this paper, we analyze stochastic dynamic pricing and advertising differential games in special oligopoly markets with constant price and advertising elasticity. We consider the sale of perishable as well as durable goods and include adoption effects in the demand. Based on a unique stochastic feedback Nash equilibrium, we derive closed-form solution formulas of the value functions and the optimal feedback policies of all competing firms. Efficient simulation techniques are used to evaluate optimally controlled sales processes over time. This way, the evolution of optimal controls as well as the firms' profit distributions are analyzed. Moreover, we are able to compare feedback solutions of the stochastic model with its deterministic counterpart. We show that the market power of the competing firms is exactly the same as in the deterministic version of the model. Further, we discover two fundamental effects that determine the relation between both models. First, the volatility in demand results in a decline of expected profits compared to the deterministic model. Second, we find that saturation effects in demand have an opposite character. We show that the second effect can be strong enough to either exactly balance or even overcompensate the first one. As a result we are able to identify cases in which feedback solutions of the deterministic model provide useful approximations of solutions of the stochastic model.}, language = {en} } @article{ScheibelTrappLimbergeretal.2020, author = {Scheibel, Willy and Trapp, Matthias and Limberger, Daniel and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {A taxonomy of treemap visualization techniques}, series = {Science and Technology Publications}, journal = {Science and Technology Publications}, publisher = {Springer}, address = {Berlin}, pages = {8}, year = {2020}, abstract = {A treemap is a visualization that has been specifically designed to facilitate the exploration of tree-structured data and, more general, hierarchically structured data. The family of visualization techniques that use a visual metaphor for parent-child relationships based "on the property of containment" (Johnson, 1993) is commonly referred to as treemaps. However, as the number of variations of treemaps grows, it becomes increasingly important to distinguish clearly between techniques and their specific characteristics. This paper proposes to discern between Space-filling Treemap TS, Containment Treemap TC, Implicit Edge Representation Tree TIE, and Mapped Tree TMT for classification of hierarchy visualization techniques and highlights their respective properties. This taxonomy is created as a hyponymy, i.e., its classes have an is-a relationship to one another: TS TC TIE TMT. With this proposal, we intend to stimulate a discussion on a more unambiguous classification of treemaps and, furthermore, broaden what is understood by the concept of treemap itself.}, language = {en} } @misc{SahlmannSchefflerSchnor2018, author = {Sahlmann, Kristina and Scheffler, Thomas and Schnor, Bettina}, title = {Ontology-driven Device Descriptions for IoT Network Management}, series = {2018 Global Internet of Things Summit (GIoTS)}, journal = {2018 Global Internet of Things Summit (GIoTS)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-6451-3}, doi = {10.1109/GIOTS.2018.8534569}, pages = {295 -- 300}, year = {2018}, abstract = {One particular challenge in the Internet of Things is the management of many heterogeneous things. The things are typically constrained devices with limited memory, power, network and processing capacity. Configuring every device manually is a tedious task. We propose an interoperable way to configure an IoT network automatically using existing standards. The proposed NETCONF-MQTT bridge intermediates between the constrained devices (speaking MQTT) and the network management standard NETCONF. The NETCONF-MQTT bridge generates dynamically YANG data models from the semantic description of the device capabilities based on the oneM2M ontology. We evaluate the approach for two use cases, i.e. describing an actuator and a sensor scenario.}, language = {en} } @article{RuetherSebodeLohseetal.2021, author = {R{\"u}ther, Ferenc Darius and Sebode, Marcial and Lohse, Ansgar W. and Wernicke, Sarah and B{\"o}ttinger, Erwin and Casar, Christian and Braun, Felix and Schramm, Christoph}, title = {Mobile app requirements for patients with rare liver diseases}, series = {Clinics and research in hepatology and gastroenterology}, volume = {45}, journal = {Clinics and research in hepatology and gastroenterology}, number = {6}, publisher = {Elsevier Masson}, address = {Amsterdam}, issn = {2210-7401}, doi = {10.1016/j.clinre.2021.101760}, pages = {10}, year = {2021}, abstract = {Background: More patient data are needed to improve research on rare liver diseases. Mobile health apps enable an exhaustive data collection. Therefore, the European Reference Network on Hepatological diseases (ERN RARE-LIVER) intends to implement an app for patients with rare liver diseases communicating with a patient registry, but little is known about which features patients and their healthcare providers regard as being useful. Aims: This study aimed to investigate how an app for rare liver diseases would be accepted, and to find out which features are considered useful. Methods: An anonymous survey was conducted on adult patients with rare liver diseases at a single academic, tertiary care outpatient-service. Additionally, medical experts of the ERN working group on autoimmune hepatitis were invited to participate in an online survey. Results: In total, the responses from 100 patients with autoimmune (n = 90) or other rare (n = 10) liver diseases and 32 experts were analyzed. Patients were convinced to use a disease specific app (80\%) and expected some benefit to their health (78\%) but responses differed signifi-cantly between younger and older patients (93\% vs. 62\%, p < 0.001; 88\% vs. 64\%, p < 0.01). Comparing patients' and experts' feedback, patients more often expected a simplified healthcare pathway (e.g. 89\% vs. 59\% (p < 0.001) wanted access to one's own medical records), while healthcare providers saw the benefit mainly in improving compliance and treatment outcome (e.g. 93\% vs. 31\% (p < 0.001) and 70\% vs. 21\% (p < 0.001) expected the app to reduce mistakes in taking medication and improve quality of life, respectively).}, language = {en} } @misc{RischKrestel2018, author = {Risch, Julian and Krestel, Ralf}, title = {My Approach = Your Apparatus?}, series = {Libraries}, journal = {Libraries}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-5178-2}, issn = {2575-7865}, doi = {10.1145/3197026.3197038}, pages = {283 -- 292}, year = {2018}, abstract = {Comparative text mining extends from genre analysis and political bias detection to the revelation of cultural and geographic differences, through to the search for prior art across patents and scientific papers. These applications use cross-collection topic modeling for the exploration, clustering, and comparison of large sets of documents, such as digital libraries. However, topic modeling on documents from different collections is challenging because of domain-specific vocabulary. We present a cross-collection topic model combined with automatic domain term extraction and phrase segmentation. This model distinguishes collection-specific and collection-independent words based on information entropy and reveals commonalities and differences of multiple text collections. We evaluate our model on patents, scientific papers, newspaper articles, forum posts, and Wikipedia articles. In comparison to state-of-the-art cross-collection topic modeling, our model achieves up to 13\% higher topic coherence, up to 4\% lower perplexity, and up to 31\% higher document classification accuracy. More importantly, our approach is the first topic model that ensures disjunct general and specific word distributions, resulting in clear-cut topic representations.}, language = {en} } @article{RischKrestel2019, author = {Risch, Julian and Krestel, Ralf}, title = {Domain-specific word embeddings for patent classification}, series = {Data Technologies and Applications}, volume = {53}, journal = {Data Technologies and Applications}, number = {1}, publisher = {Emerald Group Publishing Limited}, address = {Bingley}, issn = {2514-9288}, doi = {10.1108/DTA-01-2019-0002}, pages = {108 -- 122}, year = {2019}, abstract = {Purpose Patent offices and other stakeholders in the patent domain need to classify patent applications according to a standardized classification scheme. The purpose of this paper is to examine the novelty of an application it can then be compared to previously granted patents in the same class. Automatic classification would be highly beneficial, because of the large volume of patents and the domain-specific knowledge needed to accomplish this costly manual task. However, a challenge for the automation is patent-specific language use, such as special vocabulary and phrases. Design/methodology/approach To account for this language use, the authors present domain-specific pre-trained word embeddings for the patent domain. The authors train the model on a very large data set of more than 5m patents and evaluate it at the task of patent classification. To this end, the authors propose a deep learning approach based on gated recurrent units for automatic patent classification built on the trained word embeddings. Findings Experiments on a standardized evaluation data set show that the approach increases average precision for patent classification by 17 percent compared to state-of-the-art approaches. In this paper, the authors further investigate the model's strengths and weaknesses. An extensive error analysis reveals that the learned embeddings indeed mirror patent-specific language use. The imbalanced training data and underrepresented classes are the most difficult remaining challenge. Originality/value The proposed approach fulfills the need for domain-specific word embeddings for downstream tasks in the patent domain, such as patent classification or patent analysis.}, language = {en} } @article{RischKrestel2020, author = {Risch, Julian and Krestel, Ralf}, title = {Toxic comment detection in online discussions}, series = {Deep learning-based approaches for sentiment analysis}, journal = {Deep learning-based approaches for sentiment analysis}, editor = {Agarwal, Basant and Nayak, Richi and Mittal, Namita and Patnaik, Srikanta}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-15-1216-2}, issn = {2524-7565}, doi = {10.1007/978-981-15-1216-2_4}, pages = {85 -- 109}, year = {2020}, abstract = {Comment sections of online news platforms are an essential space to express opinions and discuss political topics. In contrast to other online posts, news discussions are related to particular news articles, comments refer to each other, and individual conversations emerge. However, the misuse by spammers, haters, and trolls makes costly content moderation necessary. Sentiment analysis can not only support moderation but also help to understand the dynamics of online discussions. A subtask of content moderation is the identification of toxic comments. To this end, we describe the concept of toxicity and characterize its subclasses. Further, we present various deep learning approaches, including datasets and architectures, tailored to sentiment analysis in online discussions. One way to make these approaches more comprehensible and trustworthy is fine-grained instead of binary comment classification. On the downside, more classes require more training data. Therefore, we propose to augment training data by using transfer learning. We discuss real-world applications, such as semi-automated comment moderation and troll detection. Finally, we outline future challenges and current limitations in light of most recent research publications.}, language = {en} } @article{RichlySchlosserBoissier2022, author = {Richly, Keven and Schlosser, Rainer and Boissier, Martin}, title = {Budget-conscious fine-grained configuration optimization for spatio-temporal applications}, series = {Proceedings of the VLDB Endowment}, volume = {15}, journal = {Proceedings of the VLDB Endowment}, number = {13}, publisher = {Association for Computing Machinery (ACM)}, address = {[New York]}, issn = {2150-8097}, doi = {10.14778/3565838.3565858}, pages = {4079 -- 4092}, year = {2022}, abstract = {Based on the performance requirements of modern spatio-temporal data mining applications, in-memory database systems are often used to store and process the data. To efficiently utilize the scarce DRAM capacities, modern database systems support various tuning possibilities to reduce the memory footprint (e.g., data compression) or increase performance (e.g., additional indexes). However, the selection of cost and performance balancing configurations is challenging due to the vast number of possible setups consisting of mutually dependent individual decisions. In this paper, we introduce a novel approach to jointly optimize the compression, sorting, indexing, and tiering configuration for spatio-temporal workloads. Further, we consider horizontal data partitioning, which enables the independent application of different tuning options on a fine-grained level. We propose different linear programming (LP) models addressing cost dependencies at different levels of accuracy to compute optimized tuning configurations for a given workload and memory budgets. To yield maintainable and robust configurations, we extend our LP-based approach to incorporate reconfiguration costs as well as a worst-case optimization for potential workload scenarios. Further, we demonstrate on a real-world dataset that our models allow to significantly reduce the memory footprint with equal performance or increase the performance with equal memory size compared to existing tuning heuristics.}, language = {en} } @article{RichlyBrauerSchlosser2020, author = {Richly, Keven and Brauer, Janos and Schlosser, Rainer}, title = {Predicting location probabilities of drivers to improved dispatch decisions of transportation network companies based on trajectory data}, series = {Proceedings of the 9th International Conference on Operations Research and Enterprise Systems - ICORES}, journal = {Proceedings of the 9th International Conference on Operations Research and Enterprise Systems - ICORES}, publisher = {Springer}, address = {Berlin}, pages = {12}, year = {2020}, abstract = {The demand for peer-to-peer ridesharing services increased over the last years rapidly. To cost-efficiently dispatch orders and communicate accurate pick-up times is challenging as the current location of each available driver is not exactly known since observed locations can be outdated for several seconds. The developed trajectory visualization tool enables transportation network companies to analyze dispatch processes and determine the causes of unexpected delays. As dispatching algorithms are based on the accuracy of arrival time predictions, we account for factors like noise, sample rate, technical and economic limitations as well as the duration of the entire process as they have an impact on the accuracy of spatio-temporal data. To improve dispatching strategies, we propose a prediction approach that provides a probability distribution for a driver's future locations based on patterns observed in past trajectories. We demonstrate the capabilities of our prediction results to ( i) avoid critical delays, (ii) to estimate waiting times with higher confidence, and (iii) to enable risk considerations in dispatching strategies.}, language = {en} } @misc{Richly2019, author = {Richly, Keven}, title = {A survey on trajectory data management for hybrid transactional and analytical workloads}, series = {IEEE International Conference on Big Data (Big Data)}, journal = {IEEE International Conference on Big Data (Big Data)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-5035-6}, issn = {2639-1589}, doi = {10.1109/BigData.2018.8622394}, pages = {562 -- 569}, year = {2019}, abstract = {Rapid advances in location-acquisition technologies have led to large amounts of trajectory data. This data is the foundation for a broad spectrum of services driven and improved by trajectory data mining. However, for hybrid transactional and analytical workloads, the storing and processing of rapidly accumulated trajectory data is a non-trivial task. In this paper, we present a detailed survey about state-of-the-art trajectory data management systems. To determine the relevant aspects and requirements for such systems, we developed a trajectory data mining framework, which summarizes the different steps in the trajectory data mining process. Based on the derived requirements, we analyze different concepts to store, compress, index, and process spatio-temporal data. There are various trajectory management systems, which are optimized for scalability, data footprint reduction, elasticity, or query performance. To get a comprehensive overview, we describe and compare different exciting systems. Additionally, the observed similarities in the general structure of different systems are consolidated in a general blueprint of trajectory management systems.}, language = {en} } @misc{Richly2019, author = {Richly, Keven}, title = {Leveraging spatio-temporal soccer data to define a graphical query language for game recordings}, series = {IEEE International Conference on Big Data (Big Data)}, journal = {IEEE International Conference on Big Data (Big Data)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-5035-6}, issn = {2639-1589}, doi = {10.1109/BigData.2018.8622159}, pages = {3456 -- 3463}, year = {2019}, abstract = {For professional soccer clubs, performance and video analysis are an integral part of the preparation and post-processing of games. Coaches, scouts, and video analysts extract information about strengths and weaknesses of their team as well as opponents by manually analyzing video recordings of past games. Since video recordings are an unstructured data source, it is a complex and time-intensive task to find specific game situations and identify similar patterns. In this paper, we present a novel approach to detect patterns and situations (e.g., playmaking and ball passing of midfielders) based on trajectory data. The application uses the metaphor of a tactic board to offer a graphical query language. With this interactive tactic board, the user can model a game situation or mark a specific situation in the video recording for which all matching occurrences in various games are immediately displayed, and the user can directly jump to the corresponding game scene. Through the additional visualization of key performance indicators (e.g.,the physical load of the players), the user can get a better overall assessment of situations. With the capabilities to find specific game situations and complex patterns in video recordings, the interactive tactic board serves as a useful tool to improve the video analysis process of professional sports teams.}, language = {en} } @article{RezaeiYangMeinel2020, author = {Rezaei, Mina and Yang, Haojin and Meinel, Christoph}, title = {Recurrent generative adversarial network for learning imbalanced medical image semantic segmentation}, series = {Multimedia tools and applications : an international journal}, volume = {79}, journal = {Multimedia tools and applications : an international journal}, number = {21-22}, publisher = {Springer}, address = {Dordrecht}, issn = {1380-7501}, doi = {10.1007/s11042-019-7305-1}, pages = {15329 -- 15348}, year = {2020}, abstract = {We propose a new recurrent generative adversarial architecture named RNN-GAN to mitigate imbalance data problem in medical image semantic segmentation where the number of pixels belongs to the desired object are significantly lower than those belonging to the background. A model trained with imbalanced data tends to bias towards healthy data which is not desired in clinical applications and predicted outputs by these networks have high precision and low recall. To mitigate imbalanced training data impact, we train RNN-GAN with proposed complementary segmentation mask, in addition, ordinary segmentation masks. The RNN-GAN consists of two components: a generator and a discriminator. The generator is trained on the sequence of medical images to learn corresponding segmentation label map plus proposed complementary label both at a pixel level, while the discriminator is trained to distinguish a segmentation image coming from the ground truth or from the generator network. Both generator and discriminator substituted with bidirectional LSTM units to enhance temporal consistency and get inter and intra-slice representation of the features. We show evidence that the proposed framework is applicable to different types of medical images of varied sizes. In our experiments on ACDC-2017, HVSMR-2016, and LiTS-2017 benchmarks we find consistently improved results, demonstrating the efficacy of our approach.}, language = {en} } @misc{RepkeKrestelEddingetal.2018, author = {Repke, Tim and Krestel, Ralf and Edding, Jakob and Hartmann, Moritz and Hering, Jonas and Kipping, Dennis and Schmidt, Hendrik and Scordialo, Nico and Zenner, Alexander}, title = {Beacon in the Dark}, series = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, journal = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6014-2}, doi = {10.1145/3269206.3269231}, pages = {1871 -- 1874}, year = {2018}, abstract = {The large amount of heterogeneous data in these email corpora renders experts' investigations by hand infeasible. Auditors or journalists, e.g., who are looking for irregular or inappropriate content or suspicious patterns, are in desperate need for computer-aided exploration tools to support their investigations. We present our Beacon system for the exploration of such corpora at different levels of detail. A distributed processing pipeline combines text mining methods and social network analysis to augment the already semi-structured nature of emails. The user interface ties into the resulting cleaned and enriched dataset. For the interface design we identify three objectives expert users have: gain an initial overview of the data to identify leads to investigate, understand the context of the information at hand, and have meaningful filters to iteratively focus onto a subset of emails. To this end we make use of interactive visualisations based on rearranged and aggregated extracted information to reveal salient patterns.}, language = {en} } @misc{RenzShamsMeinel2017, author = {Renz, Jan and Shams, Ahmed and Meinel, Christoph}, title = {Offline-Enabled Web-based E-Learning for Improved User Experience in Africa}, series = {2017 IEEE Africon}, journal = {2017 IEEE Africon}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-2775-4}, issn = {2153-0025}, doi = {10.1109/AFRCON.2017.8095574}, pages = {736 -- 742}, year = {2017}, abstract = {Web-based E-Learning uses Internet technologies and digital media to deliver education content to learners. Many universities in recent years apply their capacity in producing Massive Open Online Courses (MOOCs). They have been offering MOOCs with an expectation of rendering a comprehensive online apprenticeship. Typically, an online content delivery process requires an Internet connection. However, access to the broadband has never been a readily available resource in many regions. In Africa, poor and no networks are yet predominantly experienced by Internet users, frequently causing offline each moment a digital device disconnect from a network. As a result, a learning process is always disrupted, delayed and terminated in such regions. This paper raises the concern of E-Learning in poor and low bandwidths, in fact, it highlights the needs for an Offline-Enabled mode. The paper also explores technical approaches beamed to enhance the user experience inWeb-based E-Learning, particular in Africa.}, language = {en} } @misc{RenzMeinel2019, author = {Renz, Jan and Meinel, Christoph}, title = {The "Bachelor Project"}, series = {2019 IEEE Global Engineering Education Conference (EDUCON)}, journal = {2019 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-9506-7}, issn = {2165-9567}, doi = {10.1109/EDUCON.2019.8725140}, pages = {580 -- 587}, year = {2019}, abstract = {One of the challenges of educating the next generation of computer scientists is to teach them to become team players, that are able to communicate and interact not only with different IT systems, but also with coworkers and customers with a non-it background. The "bachelor project" is a project based on team work and a close collaboration with selected industry partners. The authors hosted some of the teams since spring term 2014/15. In the paper at hand we explain and discuss this concept and evaluate its success based on students' evaluation and reports. Furthermore, the technology-stack that has been used by the teams is evaluated to understand how self-organized students in IT-related projects work. We will show that and why the bachelor is the most successful educational format in the perception of the students and how this positive results can be improved by the mentors.}, language = {en} } @article{ReinTaeumelHirschfeld2017, author = {Rein, Patrick and Taeumel, Marcel and Hirschfeld, Robert}, title = {Making the domain tangible}, series = {Design Thinking Research}, journal = {Design Thinking Research}, publisher = {Springer}, address = {New York}, isbn = {978-3-319-60967-6}, doi = {10.1007/978-3-319-60967-6_9}, pages = {171 -- 194}, year = {2017}, abstract = {Programmers collaborate continuously with domain experts to explore the problem space and to shape a solution that fits the users' needs. In doing so, all parties develop a shared vocabulary, which is above all a list of named concepts and their relationships to each other. Nowadays, many programmers favor object-oriented programming because it allows them to directly represent real-world concepts and interactions from the vocabulary as code. However, when existing domain data is not yet represented as objects, it becomes a challenge to initially bring existing domain data into object-oriented systems and to keep the source code readable. While source code might be comprehensible to programmers, domain experts can struggle, given their non-programming background. We present a new approach to provide a mapping of existing data sources into the object-oriented programming environment. We support keeping the code of the domain model compact and readable while adding implicit means to access external information as internal domain objects. This should encourage programmers to explore different ways to build the software system quickly. Eventually, our approach fosters communication with the domain experts, especially at the beginning of a project. When the details in the problem space are not yet clear, the source code provides a valuable, tangible communication artifact.}, language = {en} } @article{ReinRamsonLinckeetal.2017, author = {Rein, Patrick and Ramson, Stefan and Lincke, Jens and Felgentreff, Tim and Hirschfeld, Robert}, title = {Group-Based Behavior Adaptation Mechanisms in Object-Oriented Systems}, series = {IEEE software}, volume = {34}, journal = {IEEE software}, number = {6}, publisher = {Inst. of Electr. and Electronics Engineers}, address = {Los Alamitos}, issn = {0740-7459}, doi = {10.1109/MS.2017.4121224}, pages = {78 -- 82}, year = {2017}, abstract = {Dynamic and distributed systems require behavior adaptations for groups of objects. Group-based behavior adaptation mechanisms scope adaptations to objects matching conditions beyond class membership. The specification of groups can be explicit or implicit.}, language = {en} } @misc{ReimannKlingbeilPasewaldtetal.2018, author = {Reimann, Max and Klingbeil, Mandy and Pasewaldt, Sebastian and Semmo, Amir and Trapp, Matthias and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {MaeSTrO: A Mobile App for Style Transfer Orchestration using Neural Networks}, series = {International Conference on Cyberworlds (CW)}, journal = {International Conference on Cyberworlds (CW)}, editor = {Sourin, A Sourina}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-7315-7}, doi = {10.1109/CW.2018.00016}, pages = {9 -- 16}, year = {2018}, abstract = {Mobile expressive rendering gained increasing popularity among users seeking casual creativity by image stylization and supports the development of mobile artists as a new user group. In particular, neural style transfer has advanced as a core technology to emulate characteristics of manifold artistic styles. However, when it comes to creative expression, the technology still faces inherent limitations in providing low-level controls for localized image stylization. This work enhances state-of-the-art neural style transfer techniques by a generalized user interface with interactive tools to facilitate a creative and localized editing process. Thereby, we first propose a problem characterization representing trade-offs between visual quality, run-time performance, and user control. We then present MaeSTrO, a mobile app for orchestration of neural style transfer techniques using iterative, multi-style generative and adaptive neural networks that can be locally controlled by on-screen painting metaphors. At this, first user tests indicate different levels of satisfaction for the implemented techniques and interaction design.}, language = {en} } @article{ReimannKlingbeilPasewaldtetal.2019, author = {Reimann, Max and Klingbeil, Mandy and Pasewaldt, Sebastian and Semmo, Amir and Trapp, Matthias and D{\"o}llner, J{\"u}rgen Roland Friedrich}, title = {Locally controllable neural style transfer on mobile devices}, series = {The Visual Computer}, volume = {35}, journal = {The Visual Computer}, number = {11}, publisher = {Springer}, address = {New York}, issn = {0178-2789}, doi = {10.1007/s00371-019-01654-1}, pages = {1531 -- 1547}, year = {2019}, abstract = {Mobile expressive rendering gained increasing popularity among users seeking casual creativity by image stylization and supports the development of mobile artists as a new user group. In particular, neural style transfer has advanced as a core technology to emulate characteristics of manifold artistic styles. However, when it comes to creative expression, the technology still faces inherent limitations in providing low-level controls for localized image stylization. In this work, we first propose a problem characterization of interactive style transfer representing a trade-off between visual quality, run-time performance, and user control. We then present MaeSTrO, a mobile app for orchestration of neural style transfer techniques using iterative, multi-style generative and adaptive neural networks that can be locally controlled by on-screen painting metaphors. At this, we enhance state-of-the-art neural style transfer techniques by mask-based loss terms that can be interactively parameterized by a generalized user interface to facilitate a creative and localized editing process. We report on a usability study and an online survey that demonstrate the ability of our app to transfer styles at improved semantic plausibility.}, language = {en} } @misc{RazzaqKaminskiRomeroetal.2018, author = {Razzaq, Misbah and Kaminski, Roland and Romero, Javier and Schaub, Torsten H. and Bourdon, Jeremie and Guziolowski, Carito}, title = {Computing diverse boolean networks from phosphoproteomic time series data}, series = {Computational Methods in Systems Biology}, volume = {11095}, journal = {Computational Methods in Systems Biology}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-319-99429-1}, issn = {0302-9743}, doi = {10.1007/978-3-319-99429-1_4}, pages = {59 -- 74}, year = {2018}, abstract = {Logical modeling has been widely used to understand and expand the knowledge about protein interactions among different pathways. Realizing this, the caspo-ts system has been proposed recently to learn logical models from time series data. It uses Answer Set Programming to enumerate Boolean Networks (BNs) given prior knowledge networks and phosphoproteomic time series data. In the resulting sequence of solutions, similar BNs are typically clustered together. This can be problematic for large scale problems where we cannot explore the whole solution space in reasonable time. Our approach extends the caspo-ts system to cope with the important use case of finding diverse solutions of a problem with a large number of solutions. We first present the algorithm for finding diverse solutions and then we demonstrate the results of the proposed approach on two different benchmark scenarios in systems biology: (1) an artificial dataset to model TCR signaling and (2) the HPN-DREAM challenge dataset to model breast cancer cell lines.}, language = {en} } @article{PuriVardeMelo2023, author = {Puri, Manish and Varde, Aparna S. and Melo, Gerard de}, title = {Commonsense based text mining on urban policy}, series = {Language resources and evaluation}, volume = {57}, journal = {Language resources and evaluation}, publisher = {Springer}, address = {Dordrecht [u.a.]}, issn = {1574-020X}, doi = {10.1007/s10579-022-09584-6}, pages = {733 -- 763}, year = {2023}, abstract = {Local laws on urban policy, i.e., ordinances directly affect our daily life in various ways (health, business etc.), yet in practice, for many citizens they remain impervious and complex. This article focuses on an approach to make urban policy more accessible and comprehensible to the general public and to government officials, while also addressing pertinent social media postings. Due to the intricacies of the natural language, ranging from complex legalese in ordinances to informal lingo in tweets, it is practical to harness human judgment here. To this end, we mine ordinances and tweets via reasoning based on commonsense knowledge so as to better account for pragmatics and semantics in the text. Ours is pioneering work in ordinance mining, and thus there is no prior labeled training data available for learning. This gap is filled by commonsense knowledge, a prudent choice in situations involving a lack of adequate training data. The ordinance mining can be beneficial to the public in fathoming policies and to officials in assessing policy effectiveness based on public reactions. This work contributes to smart governance, leveraging transparency in governing processes via public involvement. We focus significantly on ordinances contributing to smart cities, hence an important goal is to assess how well an urban region heads towards a smart city as per its policies mapping with smart city characteristics, and the corresponding public satisfaction.}, language = {en} } @misc{PufahlWongWeske2018, author = {Pufahl, Luise and Wong, Tsun Yin and Weske, Mathias}, title = {Design of an extensible BPMN process simulator}, series = {Business Process Management Workshops (BPM 2017)}, volume = {308}, journal = {Business Process Management Workshops (BPM 2017)}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-319-74030-0}, issn = {1865-1348}, doi = {10.1007/978-3-319-74030-0_62}, pages = {782 -- 795}, year = {2018}, abstract = {Business process simulation is an important means for quantitative analysis of a business process and to compare different process alternatives. With the Business Process Model and Notation (BPMN) being the state-of-the-art language for the graphical representation of business processes, many existing process simulators support already the simulation of BPMN diagrams. However, they do not provide well-defined interfaces to integrate new concepts in the simulation environment. In this work, we present the design and architecture of a proof-of-concept implementation of an open and extensible BPMN process simulator. It also supports the simulation of multiple BPMN processes at a time and relies on the building blocks of the well-founded discrete event simulation. The extensibility is assured by a plug-in concept. Its feasibility is demonstrated by extensions supporting new BPMN concepts, such as the simulation of business rule activities referencing decision models and batch activities.}, language = {en} } @article{PufahlWeske2019, author = {Pufahl, Luise and Weske, Mathias}, title = {Batch activity: enhancing business process modeling and enactment with batch processing}, series = {Computing}, volume = {101}, journal = {Computing}, number = {12}, publisher = {Springer}, address = {Wien}, issn = {0010-485X}, doi = {10.1007/s00607-019-00717-4}, pages = {1909 -- 1933}, year = {2019}, abstract = {Organizations strive for efficiency in their business processes by process improvement and automation. Business process management (BPM) supports these efforts by capturing business processes in process models serving as blueprint for a number of process instances. In BPM, process instances are typically considered running independently of each other. However, batch processing-the collectively execution of several instances at specific process activities-is a common phenomenon in operational processes to reduce cost or time. Currently, batch processing is organized manually or hard-coded in software. For allowing stakeholders to explicitly represent their batch configurations in process models and their automatic execution, this paper provides a concept for batch activities and describes the corresponding execution semantics. The batch activity concept is evaluated in a two-step approach: a prototypical implementation in an existing BPM System proves its feasibility. Additionally, batch activities are applied to different use cases in a simulated environment. Its application implies cost-savings when a suitable batch configuration is selected. The batch activity concept contributes to practice by allowing the specification of batch work in process models and their automatic execution, and to research by extending the existing process modeling concepts.}, language = {en} } @misc{PodlesnyKayemvonSchorlemeretal.2018, author = {Podlesny, Nikolai Jannik and Kayem, Anne V. D. M. and von Schorlemer, Stephan and Uflacker, Matthias}, title = {Minimising Information Loss on Anonymised High Dimensional Data with Greedy In-Memory Processing}, series = {Database and Expert Systems Applications, DEXA 2018, PT I}, volume = {11029}, journal = {Database and Expert Systems Applications, DEXA 2018, PT I}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-98809-2}, issn = {0302-9743}, doi = {10.1007/978-3-319-98809-2_6}, pages = {85 -- 100}, year = {2018}, abstract = {Minimising information loss on anonymised high dimensional data is important for data utility. Syntactic data anonymisation algorithms address this issue by generating datasets that are neither use-case specific nor dependent on runtime specifications. This results in anonymised datasets that can be re-used in different scenarios which is performance efficient. However, syntactic data anonymisation algorithms incur high information loss on high dimensional data, making the data unusable for analytics. In this paper, we propose an optimised exact quasi-identifier identification scheme, based on the notion of k-anonymity, to generate anonymised high dimensional datasets efficiently, and with low information loss. The optimised exact quasi-identifier identification scheme works by identifying and eliminating maximal partial unique column combination (mpUCC) attributes that endanger anonymity. By using in-memory processing to handle the attribute selection procedure, we significantly reduce the processing time required. We evaluated the effectiveness of our proposed approach with an enriched dataset drawn from multiple real-world data sources, and augmented with synthetic values generated in close alignment with the real-world data distributions. Our results indicate that in-memory processing drops attribute selection time for the mpUCC candidates from 400s to 100s, while significantly reducing information loss. In addition, we achieve a time complexity speed-up of O(3(n/3)) approximate to O(1.4422(n)).}, language = {en} } @misc{PlauthPolze2018, author = {Plauth, Max and Polze, Andreas}, title = {Towards improving data transfer efficiency for accelerators using hardware compression}, series = {Sixth International Symposium on Computing and Networking Workshops (CANDARW)}, journal = {Sixth International Symposium on Computing and Networking Workshops (CANDARW)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-9184-7}, doi = {10.1109/CANDARW.2018.00031}, pages = {125 -- 131}, year = {2018}, abstract = {The overhead of moving data is the major limiting factor in todays hardware, especially in heterogeneous systems where data needs to be transferred frequently between host and accelerator memory. With the increasing availability of hardware-based compression facilities in modern computer architectures, this paper investigates the potential of hardware-accelerated I/O Link Compression as a promising approach to reduce data volumes and transfer time, thus improving the overall efficiency of accelerators in heterogeneous systems. Our considerations are focused on On-the-Fly compression in both Single-Node and Scale-Out deployments. Based on a theoretical analysis, this paper demonstrates the feasibility of hardware-accelerated On-the-Fly I/O Link Compression for many workloads in a Scale-Out scenario, and for some even in a Single-Node scenario. These findings are confirmed in a preliminary evaluation using software-and hardware-based implementations of the 842 compression algorithm.}, language = {en} } @article{PiroRenard2023, author = {Piro, Vitor C. and Renard, Bernhard Y.}, title = {Contamination detection and microbiome exploration with GRIMER}, series = {GigaScience}, volume = {12}, journal = {GigaScience}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {2047-217X}, doi = {10.1093/gigascience/giad017}, pages = {13}, year = {2023}, abstract = {Background: Contamination detection is a important step that should be carefully considered in early stages when designing and performing microbiome studies to avoid biased outcomes. Detecting and removing true contaminants is challenging, especially in low-biomass samples or in studies lacking proper controls. Interactive visualizations and analysis platforms are crucial to better guide this step, to help to identify and detect noisy patterns that could potentially be contamination. Additionally, external evidence, like aggregation of several contamination detection methods and the use of common contaminants reported in the literature, could help to discover and mitigate contamination. Results: We propose GRIMER, a tool that performs automated analyses and generates a portable and interactive dashboard integrating annotation, taxonomy, and metadata. It unifies several sources of evidence to help detect contamination. GRIMER is independent of quantification methods and directly analyzes contingency tables to create an interactive and offline report. Reports can be created in seconds and are accessible for nonspecialists, providing an intuitive set of charts to explore data distribution among observations and samples and its connections with external sources. Further, we compiled and used an extensive list of possible external contaminant taxa and common contaminants with 210 genera and 627 species reported in 22 published articles. Conclusion: GRIMER enables visual data exploration and analysis, supporting contamination detection in microbiome studies. The tool and data presented are open source and available at https://gitlab.com/dacs-hpi/grimer.}, language = {en} } @article{PiroDadiSeileretal.2020, author = {Piro, Vitor C. and Dadi, Temesgen H. and Seiler, Enrico and Reinert, Knut and Renard, Bernhard Y.}, title = {ganon}, series = {Bioinformatics}, volume = {36}, journal = {Bioinformatics}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {1367-4811}, doi = {https://doi.org/10.1093/bioinformatics/btaa458}, pages = {12 -- 20}, year = {2020}, abstract = {Motivation: The exponential growth of assembled genome sequences greatly benefits metagenomics studies. However, currently available methods struggle to manage the increasing amount of sequences and their frequent updates. Indexing the current RefSeq can take days and hundreds of GB of memory on large servers. Few methods address these issues thus far, and even though many can theoretically handle large amounts of references, time/memory requirements are prohibitive in practice. As a result, many studies that require sequence classification use often outdated and almost never truly up-to-date indices. Results: Motivated by those limitations, we created ganon, a k-mer-based read classification tool that uses Interleaved Bloom Filters in conjunction with a taxonomic clustering and a k-mer counting/filtering scheme. Ganon provides an efficient method for indexing references, keeping them updated. It requires <55 min to index the complete RefSeq of bacteria, archaea, fungi and viruses. The tool can further keep these indices up-to-date in a fraction of the time necessary to create them. Ganon makes it possible to query against very large reference sets and therefore it classifies significantly more reads and identifies more species than similar methods. When classifying a high-complexity CAMI challenge dataset against complete genomes from RefSeq, ganon shows strongly increased precision with equal or better sensitivity compared with state-of-the-art tools. With the same dataset against the complete RefSeq, ganon improved the F1-score by 65\% at the genus level. It supports taxonomy- and assembly-level classification, multiple indices and hierarchical classification.}, language = {en} } @article{PerscheidSiegmundTaeumeletal.2017, author = {Perscheid, Michael and Siegmund, Benjamin and Taeumel, Marcel and Hirschfeld, Robert}, title = {Studying the advancement in debugging practice of professional software developers}, series = {Software Quality Journal}, volume = {25}, journal = {Software Quality Journal}, publisher = {Springer}, address = {Dordrecht}, issn = {0963-9314}, doi = {10.1007/s11219-015-9294-2}, pages = {83 -- 110}, year = {2017}, abstract = {In 1997, Henry Lieberman stated that debugging is the dirty little secret of computer science. Since then, several promising debugging technologies have been developed such as back-in-time debuggers and automatic fault localization methods. However, the last study about the state-of-the-art in debugging is still more than 15 years old and so it is not clear whether these new approaches have been applied in practice or not. For that reason, we investigate the current state of debugging in a comprehensive study. First, we review the available literature and learn about current approaches and study results. Second, we observe several professional developers while debugging and interview them about their experiences. Third, we create a questionnaire that serves as the basis for a larger online debugging survey. Based on these results, we present new insights into debugging practice that help to suggest new directions for future research.}, language = {en} } @article{PerscheidGrasnickUflacker2019, author = {Perscheid, Cindy and Grasnick, Bastien and Uflacker, Matthias}, title = {Integrative Gene Selection on Gene Expression Data}, series = {Journal of Integrative Bioinformatics}, volume = {16}, journal = {Journal of Integrative Bioinformatics}, number = {1}, publisher = {De Gruyter}, address = {Berlin}, issn = {1613-4516}, doi = {10.1515/jib-2018-0064}, pages = {17}, year = {2019}, abstract = {The advance of high-throughput RNA-Sequencing techniques enables researchers to analyze the complete gene activity in particular cells. From the insights of such analyses, researchers can identify disease-specific expression profiles, thus understand complex diseases like cancer, and eventually develop effective measures for diagnosis and treatment. The high dimensionality of gene expression data poses challenges to its computational analysis, which is addressed with measures of gene selection. Traditional gene selection approaches base their findings on statistical analyses of the actual expression levels, which implies several drawbacks when it comes to accurately identifying the underlying biological processes. In turn, integrative approaches include curated information on biological processes from external knowledge bases during gene selection, which promises to lead to better interpretability and improved predictive performance. Our work compares the performance of traditional and integrative gene selection approaches. Moreover, we propose a straightforward approach to integrate external knowledge with traditional gene selection approaches. We introduce a framework enabling the automatic external knowledge integration, gene selection, and evaluation. Evaluation results prove our framework to be a useful tool for evaluation and show that integration of external knowledge improves overall analysis results.}, language = {en} } @misc{PerscheidFaberKrausetal.2018, author = {Perscheid, Cindy and Faber, Lukas and Kraus, Milena and Arndt, Paul and Janke, Michael and Rehfeldt, Sebastian and Schubotz, Antje and Slosarek, Tamara and Uflacker, Matthias}, title = {A tissue-aware gene selection approach for analyzing multi-tissue gene expression data}, series = {2018 IEEE International Conference on Bioinformatics and Biomedicine (BIBM)}, journal = {2018 IEEE International Conference on Bioinformatics and Biomedicine (BIBM)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-5488-0}, issn = {2156-1125}, doi = {10.1109/BIBM.2018.8621189}, pages = {2159 -- 2166}, year = {2018}, abstract = {High-throughput RNA sequencing (RNAseq) produces large data sets containing expression levels of thousands of genes. The analysis of RNAseq data leads to a better understanding of gene functions and interactions, which eventually helps to study diseases like cancer and develop effective treatments. Large-scale RNAseq expression studies on cancer comprise samples from multiple cancer types and aim to identify their distinct molecular characteristics. Analyzing samples from different cancer types implies analyzing samples from different tissue origin. Such multi-tissue RNAseq data sets require a meaningful analysis that accounts for the inherent tissue-related bias: The identified characteristics must not originate from the differences in tissue types, but from the actual differences in cancer types. However, current analysis procedures do not incorporate that aspect. As a result, we propose to integrate a tissue-awareness into the analysis of multi-tissue RNAseq data. We introduce an extension for gene selection that provides a tissue-wise context for every gene and can be flexibly combined with any existing gene selection approach. We suggest to expand conventional evaluation by additional metrics that are sensitive to the tissue-related bias. Evaluations show that especially low complexity gene selection approaches profit from introducing tissue-awareness.}, language = {en} } @article{Perscheid2021, author = {Perscheid, Cindy}, title = {Comprior}, series = {BMC Bioinformatics}, volume = {22}, journal = {BMC Bioinformatics}, publisher = {Springer Nature}, address = {London}, issn = {1471-2105}, doi = {10.1186/s12859-021-04308-z}, pages = {1 -- 15}, year = {2021}, abstract = {Background Reproducible benchmarking is important for assessing the effectiveness of novel feature selection approaches applied on gene expression data, especially for prior knowledge approaches that incorporate biological information from online knowledge bases. However, no full-fledged benchmarking system exists that is extensible, provides built-in feature selection approaches, and a comprehensive result assessment encompassing classification performance, robustness, and biological relevance. Moreover, the particular needs of prior knowledge feature selection approaches, i.e. uniform access to knowledge bases, are not addressed. As a consequence, prior knowledge approaches are not evaluated amongst each other, leaving open questions regarding their effectiveness. Results We present the Comprior benchmark tool, which facilitates the rapid development and effortless benchmarking of feature selection approaches, with a special focus on prior knowledge approaches. Comprior is extensible by custom approaches, offers built-in standard feature selection approaches, enables uniform access to multiple knowledge bases, and provides a customizable evaluation infrastructure to compare multiple feature selection approaches regarding their classification performance, robustness, runtime, and biological relevance. Conclusion Comprior allows reproducible benchmarking especially of prior knowledge approaches, which facilitates their applicability and for the first time enables a comprehensive assessment of their effectiveness}, language = {en} } @misc{PerlichMeinel2018, author = {Perlich, Anja and Meinel, Christoph}, title = {Cooperative Note-Taking in Psychotherapy Sessions}, series = {2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom)}, journal = {2018 IEEE 20th International Conference on e-Health Networking, Applications and Services (Healthcom)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-4294-8}, pages = {6}, year = {2018}, abstract = {In the course of patient treatments, psychotherapists aim to meet the challenges of being both a trusted, knowledgeable conversation partner and a diligent documentalist. We are developing the digital whiteboard system Tele-Board MED (TBM), which allows the therapist to take digital notes during the session together with the patient. This study investigates what therapists are experiencing when they document with TBM in patient sessions for the first time and whether this documentation saves them time when writing official clinical documents. As the core of this study, we conducted four anamnesis session dialogues with behavior psychotherapists and volunteers acting in the role of patients. Following a mixed-method approach, the data collection and analysis involved self-reported emotion samples, user experience curves and questionnaires. We found that even in the very first patient session with TBM, therapists come to feel comfortable, develop a positive feeling and can concentrate on the patient. Regarding administrative documentation tasks, we found with the TBM report generation feature the therapists save 60\% of the time they normally spend on writing case reports to the health insurance.}, language = {en} } @misc{PatalasMaliszewskaKrebs2018, author = {Patalas-Maliszewska, Justyna and Krebs, Irene}, title = {An Information System Supporting the Eliciting of Expert Knowledge for Successful IT Projects}, series = {Information and Software Technologies, ICIST 2018}, volume = {920}, journal = {Information and Software Technologies, ICIST 2018}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-319-99972-2}, issn = {1865-0929}, doi = {10.1007/978-3-319-99972-2_1}, pages = {3 -- 13}, year = {2018}, abstract = {In order to guarantee the success of an IT project, it is necessary for a company to possess expert knowledge. The difficulty arises when experts no longer work for the company and it then becomes necessary to use their knowledge, in order to realise an IT project. In this paper, the ExKnowIT information system which supports the eliciting of expert knowledge for successful IT projects, is presented and consists of the following modules: (1) the identification of experts for successful IT projects, (2) the eliciting of expert knowledge on completed IT projects, (3) the expert knowledge base on completed IT projects, (4) the Group Method for Data Handling (GMDH) algorithm, (5) new knowledge in support of decisions regarding the selection of a manager for a new IT project. The added value of our system is that these three approaches, namely, the elicitation of expert knowledge, the success of an IT project and the discovery of new knowledge, gleaned from the expert knowledge base, otherwise known as the decision model, complement each other.}, language = {en} } @article{OrejasPinoNavarroetal.2018, author = {Orejas, Fernando and Pino, Elvira and Navarro, Marisa and Lambers, Leen}, title = {Institutions for navigational logics for graphical structures}, series = {Theoretical computer science}, volume = {741}, journal = {Theoretical computer science}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3975}, doi = {10.1016/j.tcs.2018.02.031}, pages = {19 -- 24}, year = {2018}, abstract = {We show that a Navigational Logic, i.e., a logic to express properties about graphs and about paths in graphs is a semi-exact institution. In this way, we can use a number of operations to structure and modularize our specifications. Moreover, using the properties of our institution, we also show how to structure single formulas, which in our formalism could be quite complex.}, language = {en} } @article{OmotoshoAyegbaEmuoyibofarheetal.2019, author = {Omotosho, Adebayo and Ayegba, Peace and Emuoyibofarhe, Justice and Meinel, Christoph}, title = {Current State of ICT in Healthcare Delivery in Developing Countries}, series = {International Journal of Online and Biomedical Engineering}, volume = {15}, journal = {International Journal of Online and Biomedical Engineering}, number = {8}, publisher = {Kassel University Press}, address = {Kassel}, issn = {2626-8493}, doi = {10.3991/ijoe.v15i08.10294}, pages = {91 -- 107}, year = {2019}, abstract = {Electronic health is one of the most popular applications of information and communication technologies and it has contributed immensely to health delivery through the provision of quality health service and ubiquitous access at a lower cost. Even though this mode of health service is increasingly becoming known or used in developing nations, these countries are faced with a myriad of challenges when implementing and deploying e-health services on both small and large scale. It is estimated that the Africa population alone carries the highest percentage of the world's global diseases despite its certain level of e-health adoption. This paper aims at analyzing the progress so far and the current state of e-health in developing countries particularly Africa and propose a framework for further improvement.}, language = {en} } @article{OmolaoyeOmolaoyeKandasamyetal.2022, author = {Omolaoye, Temidayo S. and Omolaoye, Victor Adelakun and Kandasamy, Richard K. and Hachim, Mahmood Yaseen and Du Plessis, Stefan S.}, title = {Omics and male infertility}, series = {Life : open access journal}, volume = {12}, journal = {Life : open access journal}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2075-1729}, doi = {10.3390/life12020280}, pages = {21}, year = {2022}, abstract = {Male infertility is a multifaceted disorder affecting approximately 50\% of male partners in infertile couples. Over the years, male infertility has been diagnosed mainly through semen analysis, hormone evaluations, medical records and physical examinations, which of course are fundamental, but yet inefficient, because 30\% of male infertility cases remain idiopathic. This dilemmatic status of the unknown needs to be addressed with more sophisticated and result-driven technologies and/or techniques. Genetic alterations have been linked with male infertility, thereby unveiling the practicality of investigating this disorder from the "omics" perspective. Omics aims at analyzing the structure and functions of a whole constituent of a given biological function at different levels, including the molecular gene level (genomics), transcript level (transcriptomics), protein level (proteomics) and metabolites level (metabolomics). In the current study, an overview of the four branches of omics and their roles in male infertility are briefly discussed; the potential usefulness of assessing transcriptomic data to understand this pathology is also elucidated. After assessing the publicly obtainable transcriptomic data for datasets on male infertility, a total of 1385 datasets were retrieved, of which 10 datasets met the inclusion criteria and were used for further analysis. These datasets were classified into groups according to the disease or cause of male infertility. The groups include non-obstructive azoospermia (NOA), obstructive azoospermia (OA), non-obstructive and obstructive azoospermia (NOA and OA), spermatogenic dysfunction, sperm dysfunction, and Y chromosome microdeletion. Findings revealed that 8 genes (LDHC, PDHA2, TNP1, TNP2, ODF1, ODF2, SPINK2, PCDHB3) were commonly differentially expressed between all disease groups. Likewise, 56 genes were common between NOA versus NOA and OA (ADAD1, BANF2, BCL2L14, C12orf50, C20orf173, C22orf23, C6orf99, C9orf131, C9orf24, CABS1, CAPZA3, CCDC187, CCDC54, CDKN3, CEP170, CFAP206, CRISP2, CT83, CXorf65, FAM209A, FAM71F1, FAM81B, GALNTL5, GTSF1, H1FNT, HEMGN, HMGB4, KIF2B, LDHC, LOC441601, LYZL2, ODF1, ODF2, PCDHB3, PDHA2, PGK2, PIH1D2, PLCZ1, PROCA1, RIMBP3, ROPN1L, SHCBP1L, SMCP, SPATA16, SPATA19, SPINK2, TEX33, TKTL2, TMCO2, TMCO5A, TNP1, TNP2, TSPAN16, TSSK1B, TTLL2, UBQLN3). These genes, particularly the above-mentioned 8 genes, are involved in diverse biological processes such as germ cell development, spermatid development, spermatid differentiation, regulation of proteolysis, spermatogenesis and metabolic processes. Owing to the stage-specific expression of these genes, any mal-expression can ultimately lead to male infertility. Therefore, currently available data on all branches of omics relating to male fertility can be used to identify biomarkers for diagnosing male infertility, which can potentially help in unravelling some idiopathic cases.}, language = {en} } @article{NikajWeskeMendling2019, author = {Nikaj, Adriatik and Weske, Mathias and Mendling, Jan}, title = {Semi-automatic derivation of RESTful choreographies from business process choreographies}, series = {Software and systems modeling}, volume = {18}, journal = {Software and systems modeling}, number = {2}, publisher = {Springer}, address = {Heidelberg}, issn = {1619-1366}, doi = {10.1007/s10270-017-0653-2}, pages = {1195 -- 1208}, year = {2019}, abstract = {Enterprises reach out for collaborations with other organizations in order to offer complex products and services to the market. Such collaboration and coordination between different organizations, for a good share, is facilitated by information technology. The BPMN process choreography is a modeling language for specifying the exchange of information and services between different organizations at the business level. Recently, there is a surging use of the REST architectural style for the provisioning of services on the web, but few systematic engineering approach to design their collaboration. In this paper, we address this gap in a comprehensive way by defining a semi-automatic method for the derivation of RESTful choreographies from process choreographies. The method is based on natural language analysis techniques to derive interactions from the textual information in process choreographies. The proposed method is evaluated in terms of effectiveness resulting in the intervention of a web engineer in only about 10\% of all generated RESTful interactions.}, language = {en} } @misc{NeubauerWankoSchaubetal.2018, author = {Neubauer, Kai and Wanko, Philipp and Schaub, Torsten H. and Haubelt, Christian}, title = {Exact multi-objective design space exploration using ASPmT}, series = {Proceedings of the 2018 Design, Automation \& Test in Europe Conference \& Exhibition (DATE)}, journal = {Proceedings of the 2018 Design, Automation \& Test in Europe Conference \& Exhibition (DATE)}, publisher = {IEEE}, address = {New York}, isbn = {978-3-9819-2630-9}, issn = {1530-1591}, doi = {10.23919/DATE.2018.8342014}, pages = {257 -- 260}, year = {2018}, abstract = {An efficient Design Space Exploration (DSE) is imperative for the design of modern, highly complex embedded systems in order to steer the development towards optimal design points. The early evaluation of design decisions at system-level abstraction layer helps to find promising regions for subsequent development steps in lower abstraction levels by diminishing the complexity of the search problem. In recent works, symbolic techniques, especially Answer Set Programming (ASP) modulo Theories (ASPmT), have been shown to find feasible solutions of highly complex system-level synthesis problems with non-linear constraints very efficiently. In this paper, we present a novel approach to a holistic system-level DSE based on ASPmT. To this end, we include additional background theories that concurrently guarantee compliance with hard constraints and perform the simultaneous optimization of several design objectives. We implement and compare our approach with a state-of-the-art preference handling framework for ASP. Experimental results indicate that our proposed method produces better solutions with respect to both diversity and convergence to the true Pareto front.}, language = {en} } @article{NavarroOrejasPinoetal.2021, author = {Navarro, Marisa and Orejas, Fernando and Pino, Elvira and Lambers, Leen}, title = {A navigational logic for reasoning about graph properties}, series = {Journal of logical and algebraic methods in programming}, volume = {118}, journal = {Journal of logical and algebraic methods in programming}, publisher = {Elsevier Science}, address = {Amsterdam [u.a.]}, issn = {2352-2208}, doi = {10.1016/j.jlamp.2020.100616}, pages = {33}, year = {2021}, abstract = {Graphs play an important role in many areas of Computer Science. In particular, our work is motivated by model-driven software development and by graph databases. For this reason, it is very important to have the means to express and to reason about the properties that a given graph may satisfy. With this aim, in this paper we present a visual logic that allows us to describe graph properties, including navigational properties, i.e., properties about the paths in a graph. The logic is equipped with a deductive tableau method that we have proved to be sound and complete.}, language = {en} } @article{MoeringdeMutiis2019, author = {M{\"o}ring, Sebastian and de Mutiis, Marco}, title = {Camera Ludica}, series = {Intermedia games - Games inter media : Video games and intermediality}, journal = {Intermedia games - Games inter media : Video games and intermediality}, publisher = {Bloomsbury academic}, address = {New York}, isbn = {978-1-5013-3051-3}, pages = {69 -- 93}, year = {2019}, language = {en} } @article{MoontahaSchumannArnrich2023, author = {Moontaha, Sidratul and Schumann, Franziska Elisabeth Friederike and Arnrich, Bert}, title = {Online learning for wearable EEG-Based emotion classification}, series = {Sensors}, volume = {23}, journal = {Sensors}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s23052387}, pages = {23}, year = {2023}, abstract = {Giving emotional intelligence to machines can facilitate the early detection and prediction of mental diseases and symptoms. Electroencephalography (EEG)-based emotion recognition is widely applied because it measures electrical correlates directly from the brain rather than indirect measurement of other physiological responses initiated by the brain. Therefore, we used non-invasive and portable EEG sensors to develop a real-time emotion classification pipeline. The pipeline trains different binary classifiers for Valence and Arousal dimensions from an incoming EEG data stream achieving a 23.9\% (Arousal) and 25.8\% (Valence) higher F1-Score on the state-of-art AMIGOS dataset than previous work. Afterward, the pipeline was applied to the curated dataset from 15 participants using two consumer-grade EEG devices while watching 16 short emotional videos in a controlled environment. Mean F1-Scores of 87\% (Arousal) and 82\% (Valence) were achieved for an immediate label setting. Additionally, the pipeline proved to be fast enough to achieve predictions in real-time in a live scenario with delayed labels while continuously being updated. The significant discrepancy from the readily available labels on the classification scores leads to future work to include more data. Thereafter, the pipeline is ready to be used for real-time applications of emotion classification.}, language = {en} } @article{MontiRautenstrauchGhanbarietal.2022, author = {Monti, Remo and Rautenstrauch, Pia and Ghanbari, Mahsa and Rani James, Alva and Kirchler, Matthias and Ohler, Uwe and Konigorski, Stefan and Lippert, Christoph}, title = {Identifying interpretable gene-biomarker associations with functionally informed kernel-based tests in 190,000 exomes}, series = {Nature Communications}, volume = {13}, journal = {Nature Communications}, publisher = {Nature Publishing Group UK}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-022-32864-2}, pages = {16}, year = {2022}, abstract = {Here we present an exome-wide rare genetic variant association study for 30 blood biomarkers in 191,971 individuals in the UK Biobank. We compare gene- based association tests for separate functional variant categories to increase interpretability and identify 193 significant gene-biomarker associations. Genes associated with biomarkers were ~ 4.5-fold enriched for conferring Mendelian disorders. In addition to performing weighted gene-based variant collapsing tests, we design and apply variant-category-specific kernel-based tests that integrate quantitative functional variant effect predictions for mis- sense variants, splicing and the binding of RNA-binding proteins. For these tests, we present a computationally efficient combination of the likelihood- ratio and score tests that found 36\% more associations than the score test alone while also controlling the type-1 error. Kernel-based tests identified 13\% more associations than their gene-based collapsing counterparts and had advantages in the presence of gain of function missense variants. We introduce local collapsing by amino acid position for missense variants and use it to interpret associations and identify potential novel gain of function variants in PIEZO1. Our results show the benefits of investigating different functional mechanisms when performing rare-variant association tests, and demonstrate pervasive rare-variant contribution to biomarker variability.}, language = {en} } @article{MenningGrasnickEwaldetal.2018, author = {Menning, Axel and Grasnick, Bastien M. and Ewald, Benedikt and Dobrigkeit, Franziska and Nicolai, Claudia}, title = {Verbal focus shifts}, series = {Design Studies}, volume = {57}, journal = {Design Studies}, publisher = {Elsevier}, address = {Oxford}, issn = {0142-694X}, doi = {10.1016/j.destud.2018.03.003}, pages = {135 -- 155}, year = {2018}, abstract = {Previous studies on design behaviour indicate that focus shifts positively influence ideational productivity. In this study we want to take a closer look at how these focus shifts look on the verbal level. We describe a mutually influencing relationship between mental focus shifts and verbal low coherent statements. In a case study based on the DTRS11 dataset we identify 297 low coherent statements via a combined topic modelling and manual approach. We introduce a categorization of the different instances of low coherent statements. The results indicate that designers tend to shift topics within an existing design issue instead of completely disrupting it. (C) 2018 Elsevier Ltd. All rights reserved.}, language = {en} } @article{MaximovaGieseKrause2018, author = {Maximova, Maria and Giese, Holger and Krause, Christian}, title = {Probabilistic timed graph transformation systems}, series = {Journal of Logical and Algebraic Methods in Programming}, volume = {101}, journal = {Journal of Logical and Algebraic Methods in Programming}, publisher = {Elsevier}, address = {New York}, issn = {2352-2208}, doi = {10.1016/j.jlamp.2018.09.003}, pages = {110 -- 131}, year = {2018}, abstract = {Today, software has become an intrinsic part of complex distributed embedded real-time systems. The next generation of embedded real-time systems will interconnect the today unconnected systems via complex software parts and the service-oriented paradigm. Due to these interconnections, the architecture of systems can be subject to changes at run-time, e.g. when dynamic binding of service end-points is employed or complex collaborations are established dynamically. However, suitable formalisms and techniques that allow for modeling and analysis of timed and probabilistic behavior of such systems as well as of their structure dynamics do not exist so far. To fill the identified gap, we propose Probabilistic Timed Graph Transformation Systems (PTGTSs) as a high-level description language that supports all the necessary aspects of structure dynamics, timed behavior, and probabilistic behavior. We introduce the formal model of PTGTSs in this paper as well as present and formally verify a mapping of models with finite state spaces to probabilistic timed automata (PTA) that allows to use the PRISM model checker to analyze PTGTS models with respect to PTCTL properties. (C) 2018 Elsevier Inc. All rights reserved.}, language = {en} } @misc{MatthiesTeusnerHesse2018, author = {Matthies, Christoph and Teusner, Ralf and Hesse, G{\"u}nter}, title = {Beyond Surveys}, series = {2018 IEEE Frontiers in Education (FIE) Conference}, journal = {2018 IEEE Frontiers in Education (FIE) Conference}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-1174-6}, issn = {0190-5848}, pages = {9}, year = {2018}, language = {en} } @misc{Matthies2019, author = {Matthies, Christoph}, title = {Agile process improvement in retrospectives}, series = {41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)}, journal = {41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-7281-1764-5}, issn = {2574-1934}, doi = {10.1109/ICSE-Companion.2019.00063}, pages = {150 -- 152}, year = {2019}, abstract = {Working in iterations and repeatedly improving team workflows based on collected feedback is fundamental to agile software development processes. Scrum, the most popular agile method, provides dedicated retrospective meetings to reflect on the last development iteration and to decide on process improvement actions. However, agile methods do not prescribe how these improvement actions should be identified, managed or tracked in detail. The approaches to detect and remove problems in software development processes are therefore often based on intuition and prior experiences and perceptions of team members. Previous research in this area has focused on approaches to elicit a team's improvement opportunities as well as measurements regarding the work performed in an iteration, e.g. Scrum burn-down charts. Little research deals with the quality and nature of identified problems or how progress towards removing issues is measured. In this research, we investigate how agile development teams in the professional software industry organize their feedback and process improvement approaches. In particular, we focus on the structure and content of improvement and reflection meetings, i.e. retrospectives, and their outcomes. Researching how the vital mechanism of process improvement is implemented in practice in modern software development leads to a more complete picture of agile process improvement.}, language = {en} } @misc{Matthies2019, author = {Matthies, Christoph}, title = {Feedback in Scrum}, series = {2019 IEEE/ACM 41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)}, journal = {2019 IEEE/ACM 41st International Conference on Software Engineering: Companion Proceedings (ICSE-Companion)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-7281-1764-5}, issn = {2574-1934}, doi = {10.1109/ICSE-Companion.2019.00081}, pages = {198 -- 201}, year = {2019}, abstract = {Improving the way that teams work together by reflecting and improving the executed process is at the heart of agile processes. The idea of iterative process improvement takes various forms in different agile development methodologies, e.g. Scrum Retrospectives. However, these methods do not prescribe how improvement steps should be conducted in detail. In this research we investigate how agile software teams can use their development data, such as commits or tickets, created during regular development activities, to drive and track process improvement steps. Our previous research focused on data-informed process improvement in the context of student teams, where controlled circumstances and deep domain knowledge allowed creation and usage of specific process measures. Encouraged by positive results in this area, we investigate the process improvement approaches employed in industry teams. Researching how the vital mechanism of process improvement is implemented and how development data is already being used in practice in modern software development leads to a more complete picture of agile process improvement. It is the first step in enabling a data-informed feedback and improvement process, tailored to a team's context and based on the development data of individual teams.}, language = {en} } @misc{Matthies2018, author = {Matthies, Christoph}, title = {Scrum2kanban}, series = {Proceedings of the 2nd International Workshop on Software Engineering Education for Millennials}, journal = {Proceedings of the 2nd International Workshop on Software Engineering Education for Millennials}, publisher = {IEEE}, address = {New York}, isbn = {978-1-45035-750-0}, doi = {10.1145/3194779.3194784}, pages = {48 -- 55}, year = {2018}, abstract = {Using university capstone courses to teach agile software development methodologies has become commonplace, as agile methods have gained support in professional software development. This usually means students are introduced to and work with the currently most popular agile methodology: Scrum. However, as the agile methods employed in the industry change and are adapted to different contexts, university courses must follow suit. A prime example of this is the Kanban method, which has recently gathered attention in the industry. In this paper, we describe a capstone course design, which adds the hands-on learning of the lean principles advocated by Kanban into a capstone project run with Scrum. This both ensures that students are aware of recent process frameworks and ideas as well as gain a more thorough overview of how agile methods can be employed in practice. We describe the details of the course and analyze the participating students' perceptions as well as our observations. We analyze the development artifacts, created by students during the course in respect to the two different development methodologies. We further present a summary of the lessons learned as well as recommendations for future similar courses. The survey conducted at the end of the course revealed an overwhelmingly positive attitude of students towards the integration of Kanban into the course.}, language = {en} } @article{MarufuKayemWolthusen2018, author = {Marufu, Anesu M. C. and Kayem, Anne Voluntas dei Massah and Wolthusen, Stephen D.}, title = {The design and classification of cheating attacks on power marketing schemes in resource constrained smart micro-grids}, series = {Smart Micro-Grid Systems Security and Privacy}, volume = {71}, journal = {Smart Micro-Grid Systems Security and Privacy}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-3-319-91427-5}, doi = {10.1007/978-3-319-91427-5_6}, pages = {103 -- 144}, year = {2018}, abstract = {In this chapter, we provide a framework to specify how cheating attacks can be conducted successfully on power marketing schemes in resource constrained smart micro-grids. This is an important problem because such cheating attacks can destabilise and in the worst case result in a breakdown of the micro-grid. We consider three aspects, in relation to modelling cheating attacks on power auctioning schemes. First, we aim to specify exactly how in spite of the resource constrained character of the micro-grid, cheating can be conducted successfully. Second, we consider how mitigations can be modelled to prevent cheating, and third, we discuss methods of maintaining grid stability and reliability even in the presence of cheating attacks. We use an Automated-Cheating-Attack (ACA) conception to build a taxonomy of cheating attacks based on the idea of adversarial acquisition of surplus energy. Adversarial acquisitions of surplus energy allow malicious users to pay less for access to more power than the quota allowed for the price paid. The impact on honest users, is the lack of an adequate supply of energy to meet power demand requests. We conclude with a discussion of the performance overhead of provoking, detecting, and mitigating such attacks efficiently.}, language = {en} } @misc{MalchowBauerMeinel2018, author = {Malchow, Martin and Bauer, Matthias and Meinel, Christoph}, title = {Embedded smart home — remote lab MOOC with optional real hardware experience for over 4000 students}, series = {Proceedings of 2018 IEEE Global Engineering Education Conference (EDUCON)}, journal = {Proceedings of 2018 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-2957-4}, issn = {2165-9567}, doi = {10.1109/EDUCON.2018.8363353}, pages = {1104 -- 1111}, year = {2018}, abstract = {MOOCs (Massive Open Online Courses) become more and more popular for learners of all ages to study further or to learn new subjects of interest. The purpose of this paper is to introduce a different MOOC course style. Typically, video content is shown teaching the student new information. After watching a video, self-test questions can be answered. Finally, the student answers weekly exams and final exams like the self test questions. Out of the points that have been scored for weekly and final exams a certificate can be issued. Our approach extends the possibility to receive points for the final score with practical programming exercises on real hardware. It allows the student to do embedded programming by communicating over GPIO pins to control LEDs and measure sensor values. Additionally, they can visualize values on an embedded display using web technologies, which are an essential part of embedded and smart home devices to communicate with common APIs. Students have the opportunity to solve all tasks within the online remote lab and at home on the same kind of hardware. The evaluation of this MOOCs indicates the interesting design for students to learn an engineering technique with new technology approaches in an appropriate, modern, supporting and motivating way of teaching.}, language = {en} } @misc{MalchowBauerMeinel2018, author = {Malchow, Martin and Bauer, Matthias and Meinel, Christoph}, title = {Enhance Learning in a Video Lecture Archive with Annotations}, series = {Proceedings of OF 2018 IEEE Global Engineering Education Conference (EDUCON)}, journal = {Proceedings of OF 2018 IEEE Global Engineering Education Conference (EDUCON)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-2957-4}, issn = {2165-9567}, pages = {849 -- 856}, year = {2018}, abstract = {When students watch learning videos online, they usually need to watch several hours of video content. In the end, not every minute of a video is relevant for the exam. Additionally, students need to add notes to clarify issues of a lecture. There are several possibilities to enhance the metadata of a video, e.g. a typical way to add user-specific information to an online video is a comment functionality, which allows users to share their thoughts and questions with the public. In contrast to common video material which can be found online, lecture videos are used for exam preparation. Due to this difference, the idea comes up to annotate lecture videos with markers and personal notes for a better understanding of the taught content. Especially, students learning for an exam use their notes to refresh their memories. To ease this learning method with lecture videos, we introduce the annotation feature in our video lecture archive. This functionality supports the students with keeping track of their thoughts by providing an intuitive interface to easily add, modify or remove their ideas. This annotation function is integrated in the video player. Hence, scrolling to a separate annotation area on the website is not necessary. Furthermore, the annotated notes can be exported together with the slide content to a PDF file, which can then be printed easily. Lecture video annotations support and motivate students to learn and watch videos from an E-Learning video archive.}, language = {en} } @phdthesis{Malchow2019, author = {Malchow, Martin}, title = {Nutzerunterst{\"u}tzung und -Motivation in E-Learning Vorlesungsarchiven und MOOCs}, school = {Universit{\"a}t Potsdam}, pages = {142}, year = {2019}, abstract = {In den letzten Jahren ist die Aufnahme und Verbreitung von Videos immer einfacher geworden. Daher sind die Relevanz und Beliebtheit zur Aufnahme von Vorlesungsvideos in den letzten Jahren stark angestiegen. Dies f{\"u}hrt zu einem großen Datenbestand an Vorlesungsvideos in den Video-Vorlesungsarchiven der Universit{\"a}ten. Durch diesen wachsenden Datenbestand wird es allerdings f{\"u}r die Studenten immer schwieriger, die relevanten Videos eines Vorlesungsarchivs aufzufinden. Zus{\"a}tzlich haben viele Lerninteressierte durch ihre allt{\"a}gliche Arbeit und famili{\"a}ren Verpflichtungen immer weniger Zeit sich mit dem Lernen zu besch{\"a}ftigen. Ein weiterer Aspekt, der das Lernen im Internet erschwert, ist, dass es durch soziale Netzwerke und anderen Online-Plattformen vielf{\"a}ltige Ablenkungsm{\"o}glichkeiten gibt. Daher ist das Ziel dieser Arbeit, M{\"o}glichkeiten aufzuzeigen, welche das E-Learning bieten kann, um Nutzer beim Lernprozess zu unterst{\"u}tzen und zu motivieren. Das Hauptkonzept zur Unterst{\"u}tzung der Studenten ist das pr{\"a}zise Auffinden von Informationen in den immer weiter wachsenden Vorlesungsvideoarchiven. Dazu werden die Vorlesungen im Voraus analysiert und die Texte der Vorlesungsfolien mit verschiedenen Methoden indexiert. Daraufhin k{\"o}nnen die Studenten mit der Suche oder dem Lecture-Butler Lerninhalte entsprechend Ihres aktuellen Wissensstandes auffinden. Die m{\"o}glichen verwendeten Technologien f{\"u}r das Auffinden wurden, sowohl technisch, als auch durch Studentenumfragen erfolgreich evaluiert. Zur Motivation von Studenten in Vorlesungsarchiven werden diverse Konzepte betrachtet und die Umsetzung evaluiert, die den Studenten interaktiv in den Lernprozess einbeziehen. Neben Vorlesungsarchiven existieren sowohl im privaten als auch im dienstlichen Weiterbildungsbereich die in den letzten Jahren immer beliebter werdenden MOOCs. Generell sind die Abschlussquoten von MOOCs allerdings mit durchschnittlich 7\% eher gering. Daher werden Motivationsl{\"o}sungen f{\"u}r MOOCs im Bereich von eingebetteten Systemen betrachtet, die in praktischen Programmierkursen Anwendung finden. Zus{\"a}tzlich wurden Kurse evaluiert, welche die Programmierung von eingebetteten Systemen behandeln. Die Verf{\"u}gbarkeit war bei Kursen von bis zu 10.000 eingeschriebenen Teilnehmern hierbei kein schwerwiegendes Problem. Die Verwendung von eingebetteten Systemen in Programmierkursen sind bei den Studenten in der praktischen Umsetzung auf sehr großes Interesse gestoßen.}, language = {de} } @misc{LosterNaumannEhmuelleretal.2018, author = {Loster, Michael and Naumann, Felix and Ehmueller, Jan and Feldmann, Benjamin}, title = {CurEx}, series = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, journal = {Proceedings of the 27th ACM International Conference on Information and Knowledge Management}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6014-2}, doi = {10.1145/3269206.3269229}, pages = {1883 -- 1886}, year = {2018}, abstract = {The integration of diverse structured and unstructured information sources into a unified, domain-specific knowledge base is an important task in many areas. A well-maintained knowledge base enables data analysis in complex scenarios, such as risk analysis in the financial sector or investigating large data leaks, such as the Paradise or Panama papers. Both the creation of such knowledge bases, as well as their continuous maintenance and curation involves many complex tasks and considerable manual effort. With CurEx, we present a modular system that allows structured and unstructured data sources to be integrated into a domain-specific knowledge base. In particular, we (i) enable the incremental improvement of each individual integration component; (ii) enable the selective generation of multiple knowledge graphs from the information contained in the knowledge base; and (iii) provide two distinct user interfaces tailored to the needs of data engineers and end-users respectively. The former has curation capabilities and controls the integration process, whereas the latter focuses on the exploration of the generated knowledge graph.}, language = {en} } @misc{LimbergerGroplerBuschmannetal.2018, author = {Limberger, Daniel and Gropler, Anne and Buschmann, Stefan and D{\"o}llner, J{\"u}rgen Roland Friedrich and Wasty, Benjamin}, title = {OpenLL}, series = {22nd International Conference Information Visualisation (IV)}, journal = {22nd International Conference Information Visualisation (IV)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-7202-0}, doi = {10.1109/iV.2018.00039}, pages = {175 -- 181}, year = {2018}, abstract = {Today's rendering APIs lack robust functionality and capabilities for dynamic, real-time text rendering and labeling, which represent key requirements for 3D application design in many fields. As a consequence, most rendering systems are barely or not at all equipped with respective capabilities. This paper drafts the unified text rendering and labeling API OpenLL intended to complement common rendering APIs, frameworks, and transmission formats. For it, various uses of static and dynamic placement of labels are showcased and a text interaction technique is presented. Furthermore, API design constraints with respect to state-of-the-art text rendering techniques are discussed. This contribution is intended to initiate a community-driven specification of a free and open label library.}, language = {en} } @article{LimanowskiLopesKecketal.2020, author = {Limanowski, Jakub and Lopes, Pedro and Keck, Janis and Baudisch, Patrick and Friston, Karl and Blankenburg, Felix}, title = {Action-dependent processing of touch in the human parietal operculum and posterior insula}, series = {Cerebral Cortex}, volume = {30}, journal = {Cerebral Cortex}, number = {2}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1047-3211}, doi = {10.1093/cercor/bhz111}, pages = {607 -- 617}, year = {2020}, abstract = {Somatosensory input generated by one's actions (i.e., self-initiated body movements) is generally attenuated. Conversely, externally caused somatosensory input is enhanced, for example, during active touch and the haptic exploration of objects. Here, we used functional magnetic resonance imaging (fMRI) to ask how the brain accomplishes this delicate weighting of self-generated versus externally caused somatosensory components. Finger movements were either self-generated by our participants or induced by functional electrical stimulation (FES) of the same muscles. During half of the trials, electrotactile impulses were administered when the (actively or passively) moving finger reached a predefined flexion threshold. fMRI revealed an interaction effect in the contralateral posterior insular cortex (pIC), which responded more strongly to touch during self-generated than during FES-induced movements. A network analysis via dynamic causal modeling revealed that connectivity from the secondary somatosensory cortex via the pIC to the supplementary motor area was generally attenuated during self-generated relative to FES-induced movements-yet specifically enhanced by touch received during self-generated, but not FES-induced movements. Together, these results suggest a crucial role of the parietal operculum and the posterior insula in differentiating self-generated from externally caused somatosensory information received from one's moving limb.}, language = {en} } @article{LewkowiczWohlbrandtBoettinger2020, author = {Lewkowicz, Daniel and Wohlbrandt, Attila and B{\"o}ttinger, Erwin}, title = {Economic impact of clinical decision support interventions based on electronic health records}, series = {BMC Health Services Research}, volume = {20}, journal = {BMC Health Services Research}, publisher = {BioMed Central}, address = {London}, issn = {1472-6963}, doi = {10.1186/s12913-020-05688-3}, pages = {12}, year = {2020}, abstract = {Background Unnecessary healthcare utilization, non-adherence to current clinical guidelines, or insufficient personalized care are perpetual challenges and remain potential major cost-drivers for healthcare systems around the world. Implementing decision support systems into clinical care is promised to improve quality of care and thereby yield substantial effects on reducing healthcare expenditure. In this article, we evaluate the economic impact of clinical decision support (CDS) interventions based on electronic health records (EHR). Methods We searched for studies published after 2014 using MEDLINE, CENTRAL, WEB OF SCIENCE, EBSCO, and TUFTS CEA registry databases that encompass an economic evaluation or consider cost outcome measures of EHR based CDS interventions. Thereupon, we identified best practice application areas and categorized the investigated interventions according to an existing taxonomy of front-end CDS tools. Results and discussion Twenty-seven studies are investigated in this review. Of those, twenty-two studies indicate a reduction of healthcare expenditure after implementing an EHR based CDS system, especially towards prevalent application areas, such as unnecessary laboratory testing, duplicate order entry, efficient transfusion practice, or reduction of antibiotic prescriptions. On the contrary, order facilitators and undiscovered malfunctions revealed to be threats and could lead to new cost drivers in healthcare. While high upfront and maintenance costs of CDS systems are a worldwide implementation barrier, most studies do not consider implementation cost. Finally, four included economic evaluation studies report mixed monetary outcome results and thus highlight the importance of further high-quality economic evaluations for these CDS systems. Conclusion Current research studies lack consideration of comparative cost-outcome metrics as well as detailed cost components in their analyses. Nonetheless, the positive economic impact of EHR based CDS interventions is highly promising, especially with regard to reducing waste in healthcare.}, language = {en} } @article{LewkowiczBoettingerSiegel2023, author = {Lewkowicz, Daniel and B{\"o}ttinger, Erwin and Siegel, Martin}, title = {Economic evaluation of digital therapeutic care apps for unsupervised treatment of low back pain}, series = {JMIR mhealth and uhealth}, volume = {11}, journal = {JMIR mhealth and uhealth}, publisher = {JMIR Publications}, address = {Toronto}, issn = {2291-5222}, doi = {10.2196/44585}, pages = {14}, year = {2023}, abstract = {Background: Digital therapeutic care (DTC) programs are unsupervised app-based treatments that provide video exercises and educational material to patients with nonspecific low back pain during episodes of pain and functional disability. German statutory health insurance can reimburse DTC programs since 2019, but evidence on efficacy and reasonable pricing remains scarce. This paper presents a probabilistic sensitivity analysis (PSA) to evaluate the efficacy and cost-utility of a DTC app against treatment as usual (TAU) in Germany. Objective: The aim of this study was to perform a PSA in the form of a Monte Carlo simulation based on the deterministic base case analysis to account for model assumptions and parameter uncertainty. We also intend to explore to what extent the results in this probabilistic analysis differ from the results in the base case analysis and to what extent a shortage of outcome data concerning quality-of-life (QoL) metrics impacts the overall results. Methods: The PSA builds upon a state-transition Markov chain with a 4-week cycle length over a model time horizon of 3 years from a recently published deterministic cost-utility analysis. A Monte Carlo simulation with 10,000 iterations and a cohort size of 10,000 was employed to evaluate the cost-utility from a societal perspective. Quality-adjusted life years (QALYs) were derived from Veterans RAND 6-Dimension (VR-6D) and Short-Form 6-Dimension (SF-6D) single utility scores. Finally, we also simulated reducing the price for a 3-month app prescription to analyze at which price threshold DTC would result in being the dominant strategy over TAU in Germany. Results: The Monte Carlo simulation yielded on average a euro135.97 (a currency exchange rate of EUR euro1=US \$1.069 is applicable) incremental cost and 0.004 incremental QALYs per person and year for the unsupervised DTC app strategy compared to in-person physiotherapy in Germany. The corresponding incremental cost-utility ratio (ICUR) amounts to an additional euro34,315.19 per additional QALY. DTC yielded more QALYs in 54.96\% of the iterations. DTC dominates TAU in 24.04\% of the iterations for QALYs. Reducing the app price in the simulation from currently euro239.96 to euro164.61 for a 3-month prescription could yield a negative ICUR and thus make DTC the dominant strategy, even though the estimated probability of DTC being more effective than TAU is only 54.96\%. Conclusions: Decision-makers should be cautious when considering the reimbursement of DTC apps since no significant treatment effect was found, and the probability of cost-effectiveness remains below 60\% even for an infinite willingness-to-pay threshold. More app-based studies involving the utilization of QoL outcome parameters are urgently needed to account for the low and limited precision of the available QoL input parameters, which are crucial to making profound recommendations concerning the cost-utility of novel apps.}, language = {en} } @article{LambersBornKosioletal.2018, author = {Lambers, Leen and Born, Kristopher and Kosiol, Jens and Str{\"u}ber, Daniel and Taentzer, Gabriele}, title = {Granularity of conflicts and dependencies in graph transformation systems}, series = {Journal of Logical and Algebraic Methods in Programming}, volume = {103}, journal = {Journal of Logical and Algebraic Methods in Programming}, publisher = {Elsevier}, address = {New York}, issn = {2352-2208}, doi = {10.1016/j.jlamp.2018.11.004}, pages = {105 -- 129}, year = {2018}, abstract = {Conflict and dependency analysis (CDA) is a static analysis for the detection of conflicting and dependent rule applications in a graph transformation system. The state-of-the-art CDA technique, critical pair analysis, provides all potential conflicts and dependencies in minimal context as critical pairs, for each pair of rules. Yet, critical pairs can be hard to understand; users are mainly interested in core information about conflicts and dependencies occurring in various combinations. In this paper, we present an approach to conflicts and dependencies in graph transformation systems based on two dimensions of granularity. The first dimension refers to the overlap considered between the rules of a given rule pair; the second one refers to the represented amount of context information about transformations in which the conflicts occur. We introduce a variety of new conflict notions, in particular, conflict atoms, conflict reasons, and minimal conflict reasons, relate them to the existing conflict notions of critical pairs and initial conflicts, and position all of these notions within our granularity approach. Finally, we introduce dual concepts for dependency analysis. As we discuss in a running example, our approach paves the way for an improved CDA technique. (C) 2018 Elsevier Inc. All rights reserved.}, language = {en} }