TY - JOUR
A1 - Peng, Junjie
A1 - Liu, Danxu
A1 - Wang, Yingtao
A1 - Zeng, Ying
A1 - Cheng, Feng
A1 - Zhang, Wenqiang
T1 - Weight-based strategy for an I/O-intensive application at a cloud data center
JF - Concurrency and computation : practice & experience
N2 - Applications with different characteristics in the cloud may have different resources preferences. However, traditional resource allocation and scheduling strategies rarely take into account the characteristics of applications. Considering that an I/O-intensive application is a typical type of application and that frequent I/O accesses, especially small files randomly accessing the disk, may lead to an inefficient use of resources and reduce the quality of service (QoS) of applications, a weight allocation strategy is proposed based on the available resources that a physical server can provide as well as the characteristics of the applications. Using the weight obtained, a resource allocation and scheduling strategy is presented based on the specific application characteristics in the data center. Extensive experiments show that the strategy is correct and can guarantee a high concurrency of I/O per second (IOPS) in a cloud data center with high QoS. Additionally, the strategy can efficiently improve the utilization of the disk and resources of the data center without affecting the service quality of applications.
KW - IOPS
KW - process scheduling
KW - random I
KW - O
KW - small files
KW - weight
Y1 - 2018
U6 - https://doi.org/10.1002/cpe.4648
SN - 1532-0626
SN - 1532-0634
VL - 30
IS - 19
PB - Wiley
CY - Hoboken
ER -
TY - JOUR
A1 - Schaub, Torsten H.
A1 - Woltran, Stefan
T1 - Answer set programming unleashed!
JF - Künstliche Intelligenz
N2 - Answer Set Programming faces an increasing popularity for problem solving in various domains. While its modeling language allows us to express many complex problems in an easy way, its solving technology enables their effective resolution. In what follows, we detail some of the key factors of its success. Answer Set Programming [ASP; Brewka et al. Commun ACM 54(12):92–103, (2011)] is seeing a rapid proliferation in academia and industry due to its easy and flexible way to model and solve knowledge-intense combinatorial (optimization) problems. To this end, ASP offers a high-level modeling language paired with high-performance solving technology. As a result, ASP systems provide out-off-the-box, general-purpose search engines that allow for enumerating (optimal) solutions. They are represented as answer sets, each being a set of atoms representing a solution. The declarative approach of ASP allows a user to concentrate on a problem’s specification rather than the computational means to solve it. This makes ASP a prime candidate for rapid prototyping and an attractive tool for teaching key AI techniques since complex problems can be expressed in a succinct and elaboration tolerant way. This is eased by the tuning of ASP’s modeling language to knowledge representation and reasoning (KRR). The resulting impact is nicely reflected by a growing range of successful applications of ASP [Erdem et al. AI Mag 37(3):53–68, 2016; Falkner et al. Industrial applications of answer set programming. K++nstliche Intelligenz (2018)]
Y1 - 2018
U6 - https://doi.org/10.1007/s13218-018-0550-z
SN - 0933-1875
SN - 1610-1987
VL - 32
IS - 2-3
SP - 105
EP - 108
PB - Springer
CY - Heidelberg
ER -
TY - GEN
A1 - Schaub, Torsten H.
A1 - Woltran, Stefan
T1 - Special issue on answer set programming
T2 - Künstliche Intelligenz
Y1 - 2018
U6 - https://doi.org/10.1007/s13218-018-0554-8
SN - 0933-1875
SN - 1610-1987
VL - 32
IS - 2-3
SP - 101
EP - 103
PB - Springer
CY - Heidelberg
ER -
TY - GEN
A1 - Fichte, Johannes Klaus
A1 - Truszczynski, Miroslaw
A1 - Woltran, Stefan
T1 - Dual-normal logic programs
BT - the forgotten class
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - Disjunctive Answer Set Programming is a powerful declarative programming paradigm with complexity beyond NP. Identifying classes of programs for which the consistency problem is in NP is of interest from the theoretical standpoint and can potentially lead to improvements in the design of answer set programming solvers. One of such classes consists of dual-normal programs, where the number of positive body atoms in proper rules is at most one. Unlike other classes of programs, dual-normal programs have received little attention so far. In this paper we study this class. We relate dual-normal programs to propositional theories and to normal programs by presenting several inter-translations. With the translation from dual-normal to normal programs at hand, we introduce the novel class of body-cycle free programs, which are in many respects dual to head-cycle free programs. We establish the expressive power of dual-normal programs in terms of SE- and UE-models, and compare them to normal programs. We also discuss the complexity of deciding whether dual-normal programs are strongly and uniformly equivalent.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 585
KW - answer set programming
KW - classes of logic programs
KW - strong and uniform equivalence
KW - propositional satisfiability
Y1 - 2019
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414490
SN - 1866-8372
IS - 585
ER -
TY - CHAP
A1 - Curzon, Paul
A1 - Kalas, Ivan
A1 - Schubert, Sigrid
A1 - Schaper, Niclas
A1 - Barnes, Jan
A1 - Kennewell, Steve
A1 - Bröker, Kathrin
A1 - Kastens, Uwe
A1 - Magenheim, Johannes
A1 - Dagiene, Valentina
A1 - Stupuriene, Gabriele
A1 - Ellis, Jason Brent
A1 - Abreu-Ellis, Carla Reis
A1 - Grillenberger, Andreas
A1 - Romeike, Ralf
A1 - Haugsbakken, Halvdan
A1 - Jones, Anthony
A1 - Lewin, Cathy
A1 - McNicol, Sarah
A1 - Nelles, Wolfgang
A1 - Neugebauer, Jonas
A1 - Ohrndorf, Laura
A1 - Schaper, Niclas
A1 - Schubert, Sigrid
A1 - Opel, Simone
A1 - Kramer, Matthias
A1 - Trommen, Michael
A1 - Pottbäcker, Florian
A1 - Ilaghef, Youssef
A1 - Passig, David
A1 - Tzuriel, David
A1 - Kedmi, Ganit Eshel
A1 - Saito, Toshinori
A1 - Webb, Mary
A1 - Weigend, Michael
A1 - Bottino, Rosa
A1 - Chioccariello, Augusto
A1 - Christensen, Rhonda
A1 - Knezek, Gerald
A1 - Gioko, Anthony Maina
A1 - Angondi, Enos Kiforo
A1 - Waga, Rosemary
A1 - Ohrndorf, Laura
A1 - Or-Bach, Rachel
A1 - Preston, Christina
A1 - Younie, Sarah
A1 - Przybylla, Mareen
A1 - Romeike, Ralf
A1 - Reynolds, Nicholas
A1 - Swainston, Andrew
A1 - Bendrups, Faye
A1 - Sysło, Maciej M.
A1 - Kwiatkowska, Anna Beata
A1 - Zieris, Holger
A1 - Gerstberger, Herbert
A1 - Müller, Wolfgang
A1 - Büchner, Steffen
A1 - Opel, Simone
A1 - Schiller, Thomas
A1 - Wegner, Christian
A1 - Zender, Raphael
A1 - Lucke, Ulrike
A1 - Diethelm, Ira
A1 - Syrbe, Jörn
A1 - Lai, Kwok-Wing
A1 - Davis, Niki
A1 - Eickelmann, Birgit
A1 - Erstad, Ola
A1 - Fisser, Petra
A1 - Gibson, David
A1 - Khaddage, Ferial
A1 - Knezek, Gerald
A1 - Micheuz, Peter
A1 - Kloos, Carlos Delgado
ED - Brinda, Torsten
ED - Reynolds, Nicholas
ED - Romeike, Ralf
ED - Schwill, Andreas
T1 - KEYCIT 2014
BT - key competencies in informatics and ICT
N2 - In our rapidly changing world it is increasingly important not only to be an expert in a chosen field of study but also to be able to respond to developments, master new approaches to solving problems, and fulfil changing requirements in the modern world and in the job market. In response to these needs key competencies in understanding, developing and using new digital technologies are being brought into focus in school and university programmes. The IFIP TC3 conference "KEYCIT – Key Competences in Informatics and ICT (KEYCIT 2014)" was held at the University of Potsdam in Germany from July 1st to 4th, 2014 and addressed the combination of key competencies, Informatics and ICT in detail. The conference was organized into strands focusing on secondary education, university education and teacher education (organized by IFIP WGs 3.1 and 3.3) and provided a forum to present and to discuss research, case studies, positions, and national perspectives in this field.
T3 - Commentarii informaticae didacticae (CID) - 7
KW - Schlüsselkompetenzen
KW - Informatik
KW - Bildung
KW - ICT
KW - Informatikdidaktik
KW - Key Competencies
KW - Informatics
KW - education
KW - ICT
KW - Computer Science Education
Y1 - 2015
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-70325
SN - 978-3-86956-292-6
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - CHAP
A1 - Rolf, Arno
A1 - Berges, Marc
A1 - Hubwieser, Peter
A1 - Kehrer, Timo
A1 - Kelter, Udo
A1 - Romeike, Ralf
A1 - Frenkel, Marcus
A1 - Karsten, Weicker
A1 - Reinhardt, Wolfgang
A1 - Mascher, Michael
A1 - Gül, Senol
A1 - Magenheim, Johannes
A1 - Raimer, Stephan
A1 - Diethelm, Ira
A1 - Dünnebier, Malte
A1 - Gabor, Kiss
A1 - Susanne, Boll
A1 - Rolf, Meinhardt
A1 - Gronewold, Sabine
A1 - Krekeler, Larissa
A1 - Jahnke, Isa
A1 - Haertel, Tobias
A1 - Mattick, Volker
A1 - Lettow, Karsten
A1 - Hafer, Jörg
A1 - Ludwig, Joachim
A1 - Schumann, Marlen
A1 - Laroque, Christoph
A1 - Schulte, Jonas
A1 - Urban, Diana
ED - Engbring, Dieter
ED - Keil, Reinhard
ED - Magenheim, Johannes
ED - Selke, Harald
T1 - HDI2010 – Tagungsband der 4. Fachtagung zur "Hochschuldidaktik Informatik"
N2 - Mit der 4. Tagung zur Hochschuldidaktik Informatik wird eine Reihe fortgesetzt, die ihren Anfang 1998 in Stuttgart unter der Überschrift „Informatik und Ausbildung“ genommen hat. Seither dienen diese Tagungen den Lehrenden im Bereich der Hochschulinformatik als Forum der Information und des Diskurses über aktuelle didaktische und bildungspolitische Entwicklungen im Bereich der Informatikausbildung. Aktuell zählen dazu insbesondere Fragen der Bildungsrelevanz informatischer Inhalte und der Herausforderung durch eine stärkere Kompetenzorientierung in der Informatik. Die eingereichten Beiträge zur HDI 2010 in Paderborn veranschaulichen unterschiedliche Bemühungen, sich mit relevanten Problemen der Informatikdidaktik an Hochschulen in Deutschland (und z. T. auch im Ausland) auseinanderzusetzen. Aus der Breite des Spektrums der Einreichungen ergaben sich zugleich Probleme bei der Begutachtung. Letztlich konnten von den zahlreichen Einreichungen nur drei die Gutachter so überzeugen, dass sie uneingeschränkt in ihrer Langfassung akzeptiert wurden. Neun weitere Einreichungen waren trotz Kritik überwiegend positiv begutachtet worden, so dass wir diese als Kurzfassung bzw. Diskussionspapier in die Tagung aufgenommen haben.
T3 - Commentarii informaticae didacticae (CID) - 4
Y1 - 2010
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-49167
SN - 978-3-86956-100-4
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Hafer, Jörg
A1 - Ludwig, Joachim
A1 - Schumann, Marlen
T1 - Fallstudien in medialen Räumen
JF - Commentarii informaticae didacticae : (CID)
N2 - Ziel dieses Beitrages ist es, das didaktische Konzept Fallstudien und seine lerntheoretisch-didaktische Begründung vorzustellen. Es wird die These begründet, dass mediale Räume für die Bearbeitung von Fallstudien lernunterstützend wirken und sich in besonderer Weise für Prozesse der Lernberatung und Lernbegleitung in der Hochschule eignen. Diese These wird entlang dem lerntheoretischen Konzept der Bedeutungsräume von Studierenden in Verbindung mit den Spezifika medialer Räume entfaltet. Für den daraus entstandenen E-Learning-Ansatz Online-Fallstudien kann hier lediglich ein Ausblick gegeben werden.
Y1 - 2010
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-64431
SN - 1868-0844
SN - 2191-1940
IS - 4
SP - 93
EP - 98
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - JOUR
A1 - Schäfer, Robin
A1 - Stede, Manfred
T1 - Argument mining on twitter
BT - a survey
JF - Information technology : it ; Methoden und innovative Anwendungen der Informatik und Informationstechnik ; Organ der Fachbereiche 3 und 4 der GI e.V. und des Fachbereichs 6 der ITG
N2 - In the last decade, the field of argument mining has grown notably. However, only relatively few studies have investigated argumentation in social media and specifically on Twitter. Here, we provide the, to our knowledge, first critical in-depth survey of the state of the art in tweet-based argument mining. We discuss approaches to modelling the structure of arguments in the context of tweet corpus annotation, and we review current progress in the task of detecting argument components and their relations in tweets. We also survey the intersection of argument mining and stance detection, before we conclude with an outlook.
KW - Argument Mining
KW - Twitter
KW - Stance Detection
Y1 - 2021
U6 - https://doi.org/10.1515/itit-2020-0053
SN - 1611-2776
SN - 2196-7032
VL - 63
IS - 1
SP - 45
EP - 58
PB - De Gruyter
CY - Berlin
ER -
TY - GEN
A1 - Arvidsson, Samuel Janne
A1 - Kwasniewski, Miroslaw
A1 - Riaño- Pachón, Diego Mauricio
A1 - Mueller-Roeber, Bernd
T1 - QuantPrime
BT - a flexible tool for reliable high-throughput primer design for quantitative PCR
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - Background
Medium- to large-scale expression profiling using quantitative polymerase chain reaction (qPCR) assays are becoming increasingly important in genomics research. A major bottleneck in experiment preparation is the design of specific primer pairs, where researchers have to make several informed choices, often outside their area of expertise. Using currently available primer design tools, several interactive decisions have to be made, resulting in lengthy design processes with varying qualities of the assays.
Results
Here we present QuantPrime, an intuitive and user-friendly, fully automated tool for primer pair design in small- to large-scale qPCR analyses. QuantPrime can be used online through the internet http://www.quantprime.de/ or on a local computer after download; it offers design and specificity checking with highly customizable parameters and is ready to use with many publicly available transcriptomes of important higher eukaryotic model organisms and plant crops (currently 295 species in total), while benefiting from exon-intron border and alternative splice variant information in available genome annotations. Experimental results with the model plant Arabidopsis thaliana, the crop Hordeum vulgare and the model green alga Chlamydomonas reinhardtii show success rates of designed primer pairs exceeding 96%.
Conclusion
QuantPrime constitutes a flexible, fully automated web application for reliable primer design for use in larger qPCR experiments, as proven by experimental data. The flexible framework is also open for simple use in other quantification applications, such as hydrolyzation probe design for qPCR and oligonucleotide probe design for quantitative in situ hybridization. Future suggestions made by users can be easily implemented, thus allowing QuantPrime to be developed into a broad-range platform for the design of RNA expression assays.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 943
KW - prime pair
KW - genome annotation
KW - specific prime pair
KW - primer pair design
KW - quantification protocol
Y1 - 2020
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431531
SN - 1866-8372
IS - 943
ER -
TY - JOUR
A1 - Ayzel, Georgy
A1 - Heistermann, Maik
T1 - The effect of calibration data length on the performance of a conceptual hydrological model versus LSTM and GRU
BT - a case study for six basins from the CAMELS dataset
JF - Computers & geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology
N2 - We systematically explore the effect of calibration data length on the performance of a conceptual hydrological model, GR4H, in comparison to two Artificial Neural Network (ANN) architectures: Long Short-Term Memory Networks (LSTM) and Gated Recurrent Units (GRU), which have just recently been introduced to the field of hydrology. We implemented a case study for six river basins across the contiguous United States, with 25 years of meteorological and discharge data. Nine years were reserved for independent validation; two years were used as a warm-up period, one year for each of the calibration and validation periods, respectively; from the remaining 14 years, we sampled increasing amounts of data for model calibration, and found pronounced differences in model performance. While GR4H required less data to converge, LSTM and GRU caught up at a remarkable rate, considering their number of parameters. Also, LSTM and GRU exhibited the higher calibration instability in comparison to GR4H. These findings confirm the potential of modern deep-learning architectures in rainfall runoff modelling, but also highlight the noticeable differences between them in regard to the effect of calibration data length.
KW - Artificial neural networks
KW - Calibration
KW - Deep learning
KW - Rainfall-runoff
KW - modelling
Y1 - 2021
U6 - https://doi.org/10.1016/j.cageo.2021.104708
SN - 0098-3004
SN - 1873-7803
VL - 149
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Kossmann, Jan
A1 - Halfpap, Stefan
A1 - Jankrift, Marcel
A1 - Schlosser, Rainer
T1 - Magic mirror in my hand, which is the best in the land?
BT - an experimental evaluation of index selection algorithms
JF - Proceedings of the VLDB Endowment
N2 - Indexes are essential for the efficient processing of database workloads. Proposed solutions for the relevant and challenging index selection problem range from metadata-based simple heuristics, over sophisticated multi-step algorithms, to approaches that yield optimal results. The main challenges are (i) to accurately determine the effect of an index on the workload cost while considering the interaction of indexes and (ii) a large number of possible combinations resulting from workloads containing many queries and massive schemata with possibly thousands of attributes.
In this work, we describe and analyze eight index selection algorithms that are based on different concepts and compare them along different dimensions, such as solution quality, runtime, multi-column support, solution granularity, and complexity. In particular, we analyze the solutions of the algorithms for the challenging analytical Join Order, TPC-H, and TPC-DS benchmarks. Afterward, we assess strengths and weaknesses, infer insights for index selection in general and each approach individually, before we give recommendations on when to use which approach.
Y1 - 2020
U6 - https://doi.org/10.14778/3407790.3407832
SN - 2150-8097
VL - 13
IS - 11
SP - 2382
EP - 2395
PB - Association for Computing Machinery
CY - New York
ER -
TY - JOUR
A1 - Kaya, Adem
A1 - Freitag, Melina A.
T1 - Conditioning analysis for discrete Helmholtz problems
JF - Computers and mathematics with applications : an international journal
N2 - In this paper, we examine conditioning of the discretization of the Helmholtz problem. Although the discrete Helmholtz problem has been studied from different perspectives, to the best of our knowledge, there is no conditioning analysis for it. We aim to fill this gap in the literature. We propose a novel method in 1D to observe the near-zero eigenvalues of a symmetric indefinite matrix. Standard classification of ill-conditioning based on the matrix condition number is not true for the discrete Helmholtz problem. We relate the ill-conditioning of the discretization of the Helmholtz problem with the condition number of the matrix. We carry out analytical conditioning analysis in 1D and extend our observations to 2D with numerical observations. We examine several discretizations. We find different regions in which the condition number of the problem shows different characteristics. We also explain the general behavior of the solutions in these regions.
KW - Helmholtz problem
KW - Condition number
KW - Ill-conditioning
KW - Indefinite
KW - matrices
Y1 - 2022
U6 - https://doi.org/10.1016/j.camwa.2022.05.016
SN - 0898-1221
SN - 1873-7668
VL - 118
SP - 171
EP - 182
PB - Elsevier Science
CY - Amsterdam
ER -
TY - JOUR
A1 - Mattis, Toni
A1 - Beckmann, Tom
A1 - Rein, Patrick
A1 - Hirschfeld, Robert
T1 - First-class concepts
BT - Reified architectural knowledge beyond dominant decompositions
JF - Journal of object technology : JOT / ETH Zürich, Department of Computer Science
N2 - Ideally, programs are partitioned into independently maintainable and understandable modules. As a system grows, its architecture gradually loses the capability to accommodate new concepts in a modular way. While refactoring is expensive and not always possible, and the programming language might lack dedicated primary language constructs to express certain cross-cutting concerns, programmers are still able to explain and delineate convoluted concepts through secondary means: code comments, use of whitespace and arrangement of code, documentation, or communicating tacit knowledge.
Secondary constructs are easy to change and provide high flexibility in communicating cross-cutting concerns and other concepts among programmers. However, such secondary constructs usually have no reified representation that can be explored and manipulated as first-class entities through the programming environment.
In this exploratory work, we discuss novel ways to express a wide range of concepts, including cross-cutting concerns, patterns, and lifecycle artifacts independently of the dominant decomposition imposed by an existing architecture. We propose the representation of concepts as first-class objects inside the programming environment that retain the capability to change as easily as code comments. We explore new tools that allow programmers to view, navigate, and change programs based on conceptual perspectives. In a small case study, we demonstrate how such views can be created and how the programming experience changes from draining programmers' attention by stretching it across multiple modules toward focusing it on cohesively presented concepts. Our designs are geared toward facilitating multiple secondary perspectives on a system to co-exist in symbiosis with the original architecture, hence making it easier to explore, understand, and explain complex contexts and narratives that are hard or impossible to express using primary modularity constructs.
KW - software engineering
KW - modularity
KW - exploratory programming
KW - program
KW - comprehension
KW - remodularization
KW - architecture recovery
Y1 - 2022
U6 - https://doi.org/10.5381/jot.2022.21.2.a6
SN - 1660-1769
VL - 21
IS - 2
SP - 1
EP - 15
PB - ETH Zürich, Department of Computer Science
CY - Zürich
ER -
TY - JOUR
A1 - Koumarelas, Ioannis
A1 - Jiang, Lan
A1 - Naumann, Felix
T1 - Data preparation for duplicate detection
JF - Journal of data and information quality : (JDIQ)
N2 - Data errors represent a major issue in most application workflows. Before any important task can take place, a certain data quality has to be guaranteed by eliminating a number of different errors that may appear in data. Typically, most of these errors are fixed with data preparation methods, such as whitespace removal. However, the particular error of duplicate records, where multiple records refer to the same entity, is usually eliminated independently with specialized techniques. Our work is the first to bring these two areas together by applying data preparation operations under a systematic approach prior to performing duplicate detection.
Our process workflow can be summarized as follows: It begins with the user providing as input a sample of the gold standard, the actual dataset, and optionally some constraints to domain-specific data preparations, such as address normalization. The preparation selection operates in two consecutive phases. First, to vastly reduce the search space of ineffective data preparations, decisions are made based on the improvement or worsening of pair similarities. Second, using the remaining data preparations an iterative leave-one-out classification process removes preparations one by one and determines the redundant preparations based on the achieved area under the precision-recall curve (AUC-PR). Using this workflow, we manage to improve the results of duplicate detection up to 19% in AUC-PR.
KW - data preparation
KW - data wrangling
KW - record linkage
KW - duplicate detection
KW - similarity measures
Y1 - 2020
U6 - https://doi.org/10.1145/3377878
SN - 1936-1955
SN - 1936-1963
VL - 12
IS - 3
PB - Association for Computing Machinery
CY - New York
ER -
TY - JOUR
A1 - Kossmann, Jan
A1 - Schlosser, Rainer
T1 - Self-driving database systems
BT - a conceptual approach
JF - Distributed and parallel databases
N2 - Challenges for self-driving database systems, which tune their physical design and configuration autonomously, are manifold: Such systems have to anticipate future workloads, find robust configurations efficiently, and incorporate knowledge gained by previous actions into later decisions. We present a component-based framework for self-driving database systems that enables database integration and development of self-managing functionality with low overhead by relying on separation of concerns. By keeping the components of the framework reusable and exchangeable, experiments are simplified, which promotes further research in that area. Moreover, to optimize multiple mutually dependent features, e.g., index selection and compression configurations, we propose a linear programming (LP) based algorithm to derive an efficient tuning order automatically. Afterwards, we demonstrate the applicability and scalability of our approach with reproducible examples.
KW - database systems
KW - self-driving
KW - recursive tuning
KW - workload prediction
KW - robustness
Y1 - 2020
U6 - https://doi.org/10.1007/s10619-020-07288-w
SN - 0926-8782
SN - 1573-7578
VL - 38
IS - 4
SP - 795
EP - 817
PB - Springer
CY - Dordrecht
ER -
TY - JOUR
A1 - Schneider, Johannes
A1 - Wenig, Phillip
A1 - Papenbrock, Thorsten
T1 - Distributed detection of sequential anomalies in univariate time series
JF - The VLDB journal : the international journal on very large data bases
N2 - The automated detection of sequential anomalies in time series is an essential task for many applications, such as the monitoring of technical systems, fraud detection in high-frequency trading, or the early detection of disease symptoms. All these applications require the detection to find all sequential anomalies possibly fast on potentially very large time series. In other words, the detection needs to be effective, efficient and scalable w.r.t. the input size. Series2Graph is an effective solution based on graph embeddings that are robust against re-occurring anomalies and can discover sequential anomalies of arbitrary length and works without training data. Yet, Series2Graph is no t scalable due to its single-threaded approach; it cannot, in particular, process arbitrarily large sequences due to the memory constraints of a single machine. In this paper, we propose our distributed anomaly detection system, short DADS, which is an efficient and scalable adaptation of Series2Graph. Based on the actor programming model, DADS distributes the input time sequence, intermediate state and the computation to all processors of a cluster in a way that minimizes communication costs and synchronization barriers. Our evaluation shows that DADS is orders of magnitude faster than S2G, scales almost linearly with the number of processors in the cluster and can process much larger input sequences due to its scale-out property.
KW - Distributed programming
KW - Sequential anomaly
KW - Actor model
KW - Data mining
KW - Time series
Y1 - 2021
U6 - https://doi.org/10.1007/s00778-021-00657-6
SN - 1066-8888
SN - 0949-877X
VL - 30
IS - 4
SP - 579
EP - 602
PB - Springer
CY - Berlin
ER -
TY - JOUR
A1 - Kleemann, Steven
T1 - Cyber warfare and the "humanization" of international humanitarian law
JF - International journal of cyber warfare and terrorism
N2 - Cyber warfare is a timely and relevant issue and one of the most controversial in international humanitarian law (IHL). The aim of IHL is to set rules and limits in terms of means and methods of warfare. In this context, a key question arises: Has digital warfare rules or limits, and if so, how are these applicable? Traditional principles, developed over a long period, are facing a new dimension of challenges due to the rise of cyber warfare. This paper argues that to overcome this new issue, it is critical that new humanity-oriented approaches is developed with regard to cyber warfare. The challenge is to establish a legal regime for cyber-attacks, successfully addressing human rights norms and standards. While clarifying this from a legal perspective, the authors can redesign the sensitive equilibrium between humanity and military necessity, weighing the humanitarian aims of IHL and the protection of civilians-in combination with international human rights law and other relevant legal regimes-in a different manner than before.
KW - cyber-attack
KW - cyberwar
KW - IHL
KW - IHRL
KW - international human rights
KW - international humanitarian law
KW - law and technology
KW - new technologies
Y1 - 2021
SN - 978-1-7998-6177-5
U6 - https://doi.org/10.4018/IJCWT.2021040101
SN - 1947-3435
SN - 1947-3443
VL - 11
IS - 2
SP - 1
EP - 11
PB - IGI Global
CY - Hershey
ER -
TY - CHAP
A1 - Banda, Gourinath
A1 - Gallagher, John P.
T1 - Constraint-based abstraction of a model checker for infinite state systems
N2 - Abstract interpretation-based model checking provides an approach to verifying properties of infinite-state systems. In practice, most previous work on abstract model checking is either restricted to verifying universal properties, or develops special techniques for temporal logics such as modal transition systems or other dual transition systems. By contrast we apply completely standard techniques for constructing abstract interpretations to the abstraction of a CTL semantic function, without restricting the kind of properties that can be verified. Furthermore we show that this leads directly to implementation of abstract model checking algorithms for abstract domains based on constraints, making use of an SMT solver.
Y1 - 2010
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-41516
ER -
TY - BOOK
A1 - Meyer, Andreas
A1 - Smirnov, Sergey
A1 - Weske, Mathias
T1 - Data in business processes
N2 - Process and data are equally important for business process management. Process data is especially relevant in the context of automated business processes, process controlling, and representation of organizations' core assets. One can discover many process modeling languages, each having a specific set of data modeling capabilities and the level of data awareness. The level of data awareness and data modeling capabilities vary significantly from one language to another. This paper evaluates several process modeling languages with respect to the role of data. To find a common ground for comparison, we develop a framework, which systematically organizes process- and data-related aspects of the modeling languages elaborating on the data aspects. Once the framework is in place, we compare twelve process modeling languages against it. We generalize the results of the comparison and identify clusters of similar languages with respect to data awareness.
N2 - Prozesse und Daten sind gleichermaßen wichtig für das Geschäftsprozessmanagement. Prozessdaten sind dabei insbesondere im Kontext der Automatisierung von Geschäftsprozessen, dem Prozesscontrolling und der Repräsentation der Vermögensgegenstände von Organisationen relevant. Es existieren viele Prozessmodellierungssprachen, von denen jede die Darstellung von Daten durch eine fest spezifizierte Menge an Modellierungskonstrukten ermöglicht. Allerdings unterscheiden sich diese Darstellungenund damit der Grad der Datenmodellierung stark untereinander. Dieser Report evaluiert verschiedene Prozessmodellierungssprachen bezüglich der Unterstützung von Datenmodellierung. Als einheitliche Grundlage entwickeln wir ein Framework, welches prozess- und datenrelevante Aspekte systematisch organisiert. Die Kriterien legen dabei das Hauptaugenmerk auf die datenrelevanten Aspekte. Nach Einführung des Frameworks vergleichen wir zwölf Prozessmodellierungssprachen gegen dieses. Wir generalisieren die Erkenntnisse aus den Vergleichen und identifizieren Cluster bezüglich des Grades der Datenmodellierung, in welche die einzelnen Sprachen eingeordnet werden.
T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 50
KW - business process modeling
KW - process modeling languages
KW - data modeling
KW - data in business processes
Y1 - 2011
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-53046
SN - 978-3-86956-144-8
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
TY - THES
A1 - Kluth, Stephan
T1 - Quantitative modeling and analysis with FMC-QE
T1 - Quantitative Modellierung und Analyse mit FMC-QE
N2 - The modeling and evaluation calculus FMC-QE, the Fundamental Modeling Concepts for Quanti-tative Evaluation [1], extends the Fundamental Modeling Concepts (FMC) for performance modeling and prediction. In this new methodology, the hierarchical service requests are in the main focus, because they are the origin of every service provisioning process. Similar to physics, these service requests are a tuple of value and unit, which enables hierarchical service request transformations at the hierarchical borders and therefore the hierarchical modeling. Through reducing the model complexity of the models by decomposing the system in different hierarchical views, the distinction between operational and control states and the calculation of the performance values on the assumption of the steady state, FMC-QE has a scalable applica-bility on complex systems. According to FMC, the system is modeled in a 3-dimensional hierarchical representation space, where system performance parameters are described in three arbitrarily fine-grained hierarchi-cal bipartite diagrams. The hierarchical service request structures are modeled in Entity Relationship Diagrams. The static server structures, divided into logical and real servers, are de-scribed as Block Diagrams. The dynamic behavior and the control structures are specified as Petri Nets, more precisely Colored Time Augmented Petri Nets. From the structures and pa-rameters of the performance model, a hierarchical set of equations is derived. The calculation of the performance values is done on the assumption of stationary processes and is based on fundamental laws of the performance analysis: Little's Law and the Forced Traffic Flow Law. Little's Law is used within the different hierarchical levels (horizontal) and the Forced Traffic Flow Law is the key to the dependencies among the hierarchical levels (vertical). This calculation is suitable for complex models and allows a fast (re-)calculation of different performance scenarios in order to support development and configuration decisions. Within the Research Group Zorn at the Hasso Plattner Institute, the work is embedded in a broader research in the development of FMC-QE. While this work is concentrated on the theoretical background, description and definition of the methodology as well as the extension and validation of the applicability, other topics are in the development of an FMC-QE modeling and evaluation tool and the usage of FMC-QE in the design of an adaptive transport layer in order to fulfill Quality of Service and Service Level Agreements in volatile service based environments. This thesis contains a state-of-the-art, the description of FMC-QE as well as extensions of FMC-QE in representative general models and case studies. In the state-of-the-art part of the thesis in chapter 2, an overview on existing Queueing Theory and Time Augmented Petri Net models and other quantitative modeling and evaluation languages and methodologies is given. Also other hierarchical quantitative modeling frameworks will be considered. The description of FMC-QE in chapter 3 consists of a summary of the foundations of FMC-QE, basic definitions, the graphical notations, the FMC-QE Calculus and the modeling of open queueing networks as an introductory example. The extensions of FMC-QE in chapter 4 consist of the integration of the summation method in order to support the handling of closed networks and the modeling of multiclass and semaphore scenarios. Furthermore, FMC-QE is compared to other performance modeling and evaluation approaches. In the case study part in chapter 5, proof-of-concept examples, like the modeling of a service based search portal, a service based SAP NetWeaver application and the Axis2 Web service framework will be provided. Finally, conclusions are given by a summary of contributions and an outlook on future work in chapter 6. [1] Werner Zorn. FMC-QE - A New Approach in Quantitative Modeling. In Hamid R. Arabnia, editor, Procee-dings of the International Conference on Modeling, Simulation and Visualization Methods (MSV 2007) within WorldComp ’07, pages 280 – 287, Las Vegas, NV, USA, June 2007. CSREA Press. ISBN 1-60132-029-9.
N2 - FMC-QE (Fundamental Modeling Concepts for Quantitative Evaluation [1]) ist eine auf FMC, den Fundamental Modeling Concepts, basierende Methodik zur Modellierung des Leistungsverhaltens von Systemen mit einem dazugehörenden Kalkül zur Erstellung von Leistungsvorhersagen wie Antwortzeiten und Durchsatz. In dieser neuen Methodik steht die Modellierung der hierarchischen Bedienanforderungen im Mittelpunkt, da sie der Ursprung aller dienstbasierenden Systeme sind. Wie in der Physik sind in FMC-QE die Bedienanforderungen Tupel aus Wert und Einheit, um Auftragstransformationen an Hierarchiegrenzen zu ermöglichen. Da die Komplexität durch eine Dekomposition in mehreren Sichten und in verschiedene hierarchische Schichten, die Unterscheidung von Operations- und Kontrollzuständen, sowie dazugehörige Berechungen unter Annahme der Stationarität reduziert wird, skaliert die Anwendbarkeit von FMC-QE auf komplexe Systeme. Gemäß FMC wird das zu modellierende System in einem 3-dimensionalen hierarchischen Beschreibungsraum dargestellt. Die quantitativen Kenngrößen der Systeme werden in drei beliebig frei-granularen hierarchischen bi-partiten Graphen beschrieben. Die hierarchische Struktur der Bedienanforderungen wird in Entity Relationship Diagrammen beschrieben. Die statischen Bedienerstrukturen, unterteilt in logische und reale Bediener, sind in Aufbaudiagrammen erläutert. Außerdem werden Petri Netze, genauer Farbige Zeit-behaftete Petri Netze, dazu verwendet, die dynamischen Abläufe, sowie die Kontrollflüsse im System zu beschreiben. Anschließend wird eine Menge von hierarchischen Gleichungen von der Struktur und den Parametern des Modells abgeleitet. Diese Gleichungen, die auf dem stationären Zustand des Systems beruhen, basieren auf den beiden Fundamental Gesetzen der Leistungsanalyse, dem Gesetz von Little und dem Verkehrsflussgesetz. Das Gesetz von Little definiert hierbei Beziehungen innerhalb einer hierarchischen Schicht (horizontal) und das Verkehrsflussgesetz wiederum Beziehungen zwischen hierarchischen Schichten (vertikal). Die Berechungen erlauben Leistungsvorhersagen für komplexe Systeme durch eine effiziente Berechnung von Leistungsgrößen für eine große Auswahl von System- und Lastkonfigurationen. Innerhalb der Forschungsgruppe von Prof. Dr.-Ing Werner Zorn am Hasso Plattner Institut an der Universität Potsdam ist die vorliegende Arbeit in einen größeren Forschungskontext im Bereich FMC-QE eingebettet. Während hier ein Fokus auf dem theoretischen Hintergrund, der Beschreibung und der Definition der Methodik als auch der Anwendbarkeit und Erweiterung gelegt wurde, sind andere Arbeiten auf dem Gebiet der Entwicklung einer Anwendung zur Modellierung und Evaluierung von Systemen mit FMC-QE bzw. der Verwendung von FMC-QE zur Entwicklung einer adaptiven Transportschicht zur Einhaltung von Dienstgüten (Quality of Service) und Dienstvereinbarungen (Service Level Agreements) in volatilen dienstbasierten Systemen beheimatet. Diese Arbeit umfasst einen Einblick in den Stand der Technik, die Beschreibung von FMC-QE sowie die Weiterentwicklung von FMC-QE in repräsentativen allgemeinen Modellen und Fallstudien. Das Kapitel 2: Stand der Technik gibt einen Überblick über die Warteschlangentheorie, Zeit-behaftete Petri Netze, weitere Leistungsbeschreibungs- und Leistungsvorhersagungstechniken sowie die Verwendung von Hierarchien in Leistungsbeschreibungstechniken. Die Beschreibung von FMC-QE in Kapitel 3 enthält die Erläuterung der Grundlagen von FMC-QE, die Beschreibung einiger Grundannahmen, der graphischen Notation, dem mathematischen Modell und einem erläuternden Beispiel. In Kapitel 4: Erweiterungen von FMC-QE wird die Behandlung weiterer allgemeiner Modelle, wie die Modellklasse von geschlossenen Netzen, Synchronisierung und Mehrklassen-Modelle beschrieben. Außerdem wird FMC-QE mit dem Stand der Technik verglichen. In Kapitel 5 werden Machbarkeitsstudien beschrieben. Schließlich werden in Kapitel 6 eine Zusammenfassung und ein Ausblick gegeben. [1] Werner Zorn. FMC-QE - A New Approach in Quantitative Modeling. In Hamid R. Arabnia, editor, Proceedings of the International Conference on Modeling, Simulation and Visualization Methods (MSV 2007) within WorldComp ’07, 280 – 287, Las Vegas, NV, USA, Juni 2007. CSREA Press. ISBN 1-60132-029-9.
KW - FMC-QE
KW - Quantitative Modellierung
KW - Leistungsvorhersage
KW - Warteschlangentheorie
KW - Zeitbehaftete Petri Netze
KW - FMC-QE
KW - Quantitative Modeling
KW - Performance Prediction
KW - Queuing Theory
KW - Time Augmented Petri Nets
Y1 - 2011
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-52987
ER -