@misc{AlhosseiniAlmodarresiYasinBinTareafNajafietal.2019, author = {Alhosseini Almodarresi Yasin, Seyed Ali and Bin Tareaf, Raad and Najafi, Pejman and Meinel, Christoph}, title = {Detect me if you can}, series = {Companion Proceedings of The 2019 World Wide Web Conference}, journal = {Companion Proceedings of The 2019 World Wide Web Conference}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-6675-5}, doi = {10.1145/3308560.3316504}, pages = {148 -- 153}, year = {2019}, abstract = {Spam Bots have become a threat to online social networks with their malicious behavior, posting misinformation messages and influencing online platforms to fulfill their motives. As spam bots have become more advanced over time, creating algorithms to identify bots remains an open challenge. Learning low-dimensional embeddings for nodes in graph structured data has proven to be useful in various domains. In this paper, we propose a model based on graph convolutional neural networks (GCNN) for spam bot detection. Our hypothesis is that to better detect spam bots, in addition to defining a features set, the social graph must also be taken into consideration. GCNNs are able to leverage both the features of a node and aggregate the features of a node's neighborhood. We compare our approach, with two methods that work solely on a features set and on the structure of the graph. To our knowledge, this work is the first attempt of using graph convolutional neural networks in spam bot detection.}, language = {en} } @misc{BordihnNagyVaszil2018, author = {Bordihn, Henning and Nagy, Benedek and Vaszil, Gy{\"o}rgy}, title = {Preface: Non-classical models of automata and applications VIII}, series = {RAIRO-Theoretical informatics and appli and applications}, volume = {52}, journal = {RAIRO-Theoretical informatics and appli and applications}, number = {2-4}, publisher = {EDP Sciences}, address = {Les Ulis}, issn = {0988-3754}, doi = {10.1051/ita/2018019}, pages = {87 -- 88}, year = {2018}, language = {en} } @misc{BosserCabalarDieguezetal.2018, author = {Bosser, Anne-Gwenn and Cabalar, Pedro and Dieguez, Martin and Schaub, Torsten H.}, title = {Introducing temporal stable models for linear dynamic logic}, series = {16th International Conference on Principles of Knowledge Representation and Reasoning}, journal = {16th International Conference on Principles of Knowledge Representation and Reasoning}, publisher = {ASSOC Association for the Advancement of Artificial Intelligence}, address = {Palo Alto}, pages = {12 -- 21}, year = {2018}, abstract = {We propose a new temporal extension of the logic of Here-and-There (HT) and its equilibria obtained by combining it with dynamic logic over (linear) traces. Unlike previous temporal extensions of HT based on linear temporal logic, the dynamic logic features allow us to reason about the composition of actions. For instance, this can be used to exercise fine grained control when planning in robotics, as exemplified by GOLOG. In this paper, we lay the foundations of our approach, and refer to it as Linear Dynamic Equilibrium Logic, or simply DEL. We start by developing the formal framework of DEL and provide relevant characteristic results. Among them, we elaborate upon the relationships to traditional linear dynamic logic and previous temporal extensions of HT.}, language = {en} } @misc{BrewkaSchaubWoltran2018, author = {Brewka, Gerhard and Schaub, Torsten H. and Woltran, Stefan}, title = {Interview with Gerhard Brewka}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0549-5}, pages = {219 -- 221}, year = {2018}, abstract = {This interview with Gerhard Brewka was conducted by correspondance in May 2018. The question set was compiled by Torsten Schaub and Stefan Woltran.}, language = {en} } @misc{BoehneKreitz2018, author = {B{\"o}hne, Sebastian and Kreitz, Christoph}, title = {Learning how to prove}, series = {Electronic proceedings in theoretical computer science}, journal = {Electronic proceedings in theoretical computer science}, number = {267}, publisher = {Open Publishing Association}, address = {Sydney}, issn = {2075-2180}, doi = {10.4204/EPTCS.267.1}, pages = {1 -- 18}, year = {2018}, abstract = {We have developed an alternative approach to teaching computer science students how to prove. First, students are taught how to prove theorems with the Coq proof assistant. In a second, more difficult, step students will transfer their acquired skills to the area of textbook proofs. In this article we present a realisation of the second step. Proofs in Coq have a high degree of formality while textbook proofs have only a medium one. Therefore our key idea is to reduce the degree of formality from the level of Coq to textbook proofs in several small steps. For that purpose we introduce three proof styles between Coq and textbook proofs, called line by line comments, weakened line by line comments, and structure faithful proofs. While this article is mostly conceptional we also report on experiences with putting our approach into practise.}, language = {en} } @misc{CabalarFandinnoSchaubetal.2019, author = {Cabalar, Pedro and Fandinno, Jorge and Schaub, Torsten H. and Schellhorn, Sebastian}, title = {Lower Bound Founded Logic of Here-and-There}, series = {Logics in Artificial Intelligence}, volume = {11468}, journal = {Logics in Artificial Intelligence}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-19570-0}, issn = {0302-9743}, doi = {10.1007/978-3-030-19570-0_34}, pages = {509 -- 525}, year = {2019}, abstract = {A distinguishing feature of Answer Set Programming is that all atoms belonging to a stable model must be founded. That is, an atom must not only be true but provably true. This can be made precise by means of the constructive logic of Here-and-There, whose equilibrium models correspond to stable models. One way of looking at foundedness is to regard Boolean truth values as ordered by letting true be greater than false. Then, each Boolean variable takes the smallest truth value that can be proven for it. This idea was generalized by Aziz to ordered domains and applied to constraint satisfaction problems. As before, the idea is that a, say integer, variable gets only assigned to the smallest integer that can be justified. In this paper, we present a logical reconstruction of Aziz' idea in the setting of the logic of Here-and-There. More precisely, we start by defining the logic of Here-and-There with lower bound founded variables along with its equilibrium models and elaborate upon its formal properties. Finally, we compare our approach with related ones and sketch future work.}, language = {en} } @misc{FabianBaumannEhlertetal.2017, author = {Fabian, Benjamin and Baumann, Annika and Ehlert, Mathias and Ververis, Vasilis and Ermakova, Tatiana}, title = {CORIA - Analyzing internet connectivity risks using network graphs}, series = {2017 IEEE International Conference on Communications (ICC)}, journal = {2017 IEEE International Conference on Communications (ICC)}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-1-4673-8999-0}, issn = {1550-3607}, doi = {10.1109/ICC.2017.7996828}, pages = {6}, year = {2017}, abstract = {The Internet can be considered as the most important infrastructure for modern society and businesses. A loss of Internet connectivity has strong negative financial impacts for businesses and economies. Therefore, assessing Internet connectivity, in particular beyond their own premises and area of direct control, is of growing importance in the face of potential failures, accidents, and malicious attacks. This paper presents CORIA, a software framework for an easy analysis of connectivity risks based on large network graphs. It provides researchers, risk analysts, network managers and security consultants with a tool to assess an organization's connectivity and paths options through the Internet backbone, including a user-friendly and insightful visual representation of results. CORIA is flexibly extensible in terms of novel data sets, graph metrics, and risk scores that enable further use cases. The performance of CORIA is evaluated by several experiments on the Internet graph and further randomly generated networks.}, language = {en} } @misc{FichteHecherMeier2019, author = {Fichte, Johannes Klaus and Hecher, Markus and Meier, Arne}, title = {Counting Complexity for Reasoning in Abstract Argumentation}, series = {The Thirty-Third AAAI Conference on Artificial Intelligence, the Thirty-First Innovative Applications of Artificial Intelligence Conference, the Ninth AAAI Symposium on Educational Advances in Artificial Intelligence}, journal = {The Thirty-Third AAAI Conference on Artificial Intelligence, the Thirty-First Innovative Applications of Artificial Intelligence Conference, the Ninth AAAI Symposium on Educational Advances in Artificial Intelligence}, publisher = {AAAI Press}, address = {Palo Alto}, isbn = {978-1-57735-809-1}, pages = {2827 -- 2834}, year = {2019}, abstract = {In this paper, we consider counting and projected model counting of extensions in abstract argumentation for various semantics. When asking for projected counts we are interested in counting the number of extensions of a given argumentation framework while multiple extensions that are identical when restricted to the projected arguments count as only one projected extension. We establish classical complexity results and parameterized complexity results when the problems are parameterized by treewidth of the undirected argumentation graph. To obtain upper bounds for counting projected extensions, we introduce novel algorithms that exploit small treewidth of the undirected argumentation graph of the input instance by dynamic programming (DP). Our algorithms run in time double or triple exponential in the treewidth depending on the considered semantics. Finally, we take the exponential time hypothesis (ETH) into account and establish lower bounds of bounded treewidth algorithms for counting extensions and projected extension.}, language = {en} } @misc{FrankKreitz2018, author = {Frank, Mario and Kreitz, Christoph}, title = {A theorem prover for scientific and educational purposes}, series = {Electronic proceedings in theoretical computer science}, journal = {Electronic proceedings in theoretical computer science}, number = {267}, publisher = {Open Publishing Association}, address = {Sydney}, issn = {2075-2180}, doi = {10.4204/EPTCS.267.4}, pages = {59 -- 69}, year = {2018}, abstract = {We present a prototype of an integrated reasoning environment for educational purposes. The presented tool is a fragment of a proof assistant and automated theorem prover. We describe the existing and planned functionality of the theorem prover and especially the functionality of the educational fragment. This currently supports working with terms of the untyped lambda calculus and addresses both undergraduate students and researchers. We show how the tool can be used to support the students' understanding of functional programming and discuss general problems related to the process of building theorem proving software that aims at supporting both research and education.}, language = {en} } @misc{Giese2017, author = {Giese, Holger}, title = {Formal models and analysis for self-adaptive cyber-physical systems}, series = {Lecture notes in computer science}, volume = {10231}, journal = {Lecture notes in computer science}, editor = {Kouchnarenko, Olga and Khosravi, Ramtin}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-57666-4}, issn = {0302-9743}, doi = {10.1007/978-3-319-57666-4_1}, pages = {3 -- 9}, year = {2017}, abstract = {In this extended abstract, we will analyze the current challenges for the envisioned Self-Adaptive CPS. In addition, we will outline our results to approach these challenges with SMARTSOS [10] a generic approach based on extensions of graph transformation systems employing open and adaptive collaborations and models at runtime for trustworthy self-adaptation, self-organization, and evolution of the individual systems and the system-of-systems level taking the independent development, operation, management, and evolution of these systems into account.}, language = {en} } @misc{KliemeTietzMeinel2018, author = {Klieme, Eric and Tietz, Christian and Meinel, Christoph}, title = {Beware of SMOMBIES}, series = {The 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (IEEE TrustCom 2018)/the 12th IEEE International Conference on Big Data Science and Engineering (IEEE BigDataSE 2018)}, journal = {The 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (IEEE TrustCom 2018)/the 12th IEEE International Conference on Big Data Science and Engineering (IEEE BigDataSE 2018)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-4387-7}, issn = {2324-9013}, doi = {10.1109/TrustCom/BigDataSE.2018.00096}, pages = {651 -- 660}, year = {2018}, abstract = {Several research evaluated the user's style of walking for the verification of a claimed identity and showed high authentication accuracies in many settings. In this paper we present a system that successfully verifies a user's identity based on many real world smartphone placements and yet not regarded interactions while walking. Our contribution is the distinction of all considered activities into three distinct subsets and a specific one-class Support Vector Machine per subset. Using sensor data of 30 participants collected in a semi-supervised study approach, we prove that unsupervised verification is possible with very low false-acceptance and false-rejection rates. We furthermore show that these subsets can be distinguished with a high accuracy and demonstrate that this system can be deployed on off-the-shelf smartphones.}, language = {en} } @misc{KrstićJentzsch2018, author = {Krstić, Miloš and Jentzsch, Anne-Kristin}, title = {Reliability, safety and security of the electronics in automated driving vehicles - joint lab lecturing approach}, series = {2018 12TH European Workshop on Microelectronics Education (EWME)}, journal = {2018 12TH European Workshop on Microelectronics Education (EWME)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-1157-9}, pages = {21 -- 22}, year = {2018}, abstract = {This paper proposes an education approach for master and bachelor students to enhance their skills in the area of reliability, safety and security of the electronic components in automated driving. The approach is based on the active synergetic work of research institutes, academia and industry in the frame of joint lab. As an example, the jointly organized summer school with the respective focus is organized and elaborated.}, language = {en} } @misc{LifschitzSchaubWoltran2018, author = {Lifschitz, Vladimir and Schaub, Torsten H. and Woltran, Stefan}, title = {Interview with Vladimir Lifschitz}, series = {K{\"u}nstliche Intelligenz}, volume = {32}, journal = {K{\"u}nstliche Intelligenz}, number = {2-3}, publisher = {Springer}, address = {Heidelberg}, issn = {0933-1875}, doi = {10.1007/s13218-018-0552-x}, pages = {213 -- 218}, year = {2018}, abstract = {This interview with Vladimir Lifschitz was conducted by Torsten Schaub at the University of Texas at Austin in August 2017. The question set was compiled by Torsten Schaub and Stefan Woltran.}, language = {en} } @misc{MarquesdeCarvalhoJuergensen2007, author = {Marques de Carvalho, Jackson W. and J{\"u}rgensen, Helmut}, title = {Flexible Structured Mathematics Notation : IADIS, International Conference Interfaces and Human Computer Interaction, Lisabon, 2007}, series = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Informatik}, volume = {2007, 1}, journal = {Preprint / Universit{\"a}t Potsdam, Institut f{\"u}r Informatik}, publisher = {Univ.}, address = {Potsdam}, issn = {0946-7580}, pages = {5 S.}, year = {2007}, language = {en} } @misc{MarweckiBaudisch2018, author = {Marwecki, Sebastian and Baudisch, Patrick}, title = {Scenograph}, series = {UIST '18: Proceedings of the 31st Annual ACM Symposium on User Interface Software and Technology}, journal = {UIST '18: Proceedings of the 31st Annual ACM Symposium on User Interface Software and Technology}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-5948-1}, doi = {10.1145/3242587.3242648}, pages = {511 -- 520}, year = {2018}, abstract = {When developing a real-walking virtual reality experience, designers generally create virtual locations to fit a specific tracking volume. Unfortunately, this prevents the resulting experience from running on a smaller or differently shaped tracking volume. To address this, we present a software system called Scenograph. The core of Scenograph is a tracking volume-independent representation of real-walking experiences. Scenograph instantiates the experience to a tracking volume of given size and shape by splitting the locations into smaller ones while maintaining narrative structure. In our user study, participants' ratings of realism decreased significantly when existing techniques were used to map a 25m2 experience to 9m2 and an L-shaped 8m2 tracking volume. In contrast, ratings did not differ when Scenograph was used to instantiate the experience.}, language = {en} } @misc{MeinelSack2004, author = {Meinel, Christoph and Sack, Harald}, title = {WWW : Kommunikation, Internetworking, Web-Technologien}, publisher = {Springer}, address = {Berlin}, isbn = {3-540-44276-6}, issn = {1439-5428}, pages = {1179 S.}, year = {2004}, language = {de} } @misc{MuehlbauerSchroederSchoelzel2017, author = {M{\"u}hlbauer, Felix and Schr{\"o}der, Lukas and Sch{\"o}lzel, Mario}, title = {On hardware-based fault-handling in dynamically scheduled processors}, series = {20th International Symposium on Design and Diagnostics of Electronic Circuits \& Systems (DDECS) 2017}, journal = {20th International Symposium on Design and Diagnostics of Electronic Circuits \& Systems (DDECS) 2017}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-0472-4}, issn = {2334-3133}, doi = {10.1109/DDECS.2017.7934572}, pages = {201 -- 206}, year = {2017}, abstract = {This paper describes architectural extensions for a dynamically scheduled processor, so that it can be used in three different operation modes, ranging from high-performance, to high-reliability. With minor hardware-extensions of the control path, the resources of the superscalar data-path can be used either for high-performance execution, fail-safe-operation, or fault-tolerant-operation. This makes the processor-architecture a very good candidate for applications with dynamically changing reliability requirements, e.g. for automotive applications. The paper reports the hardware-overhead for the extensions, and investigates the performance penalties introduced by the fail-safe and fault-tolerant mode. Furthermore, a comprehensive fault simulation was carried out in order to investigate the fault-coverage of the proposed approach.}, language = {en} } @misc{MuehlbauerSchroederSkoncejetal.2017, author = {M{\"u}hlbauer, Felix and Schr{\"o}der, Lukas and Skoncej, Patryk and Sch{\"o}lzel, Mario}, title = {Handling manufacturing and aging faults with software-based techniques in tiny embedded systems}, series = {18th IEEE Latin American Test Symposium (LATS 2017)}, journal = {18th IEEE Latin American Test Symposium (LATS 2017)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5386-0415-1}, doi = {10.1109/LATW.2017.7906756}, pages = {6}, year = {2017}, abstract = {Non-volatile memory area occupies a large portion of the area of a chip in an embedded system. Such memories are prone to manufacturing faults, retention faults, and aging faults. The paper presents a single software based technique that allows for handling all of these fault types in tiny embedded systems without the need for hardware support. This is beneficial for low-cost embedded systems with simple memory architectures. A software infrastructure and a flow are presented that demonstrate how the presented technique is used in general for fault handling right after manufacturing and in-the-field. Moreover, a full implementation is presented for a MSP430 microcontroller, along with a discussion of the performance, overhead, and reliability impacts.}, language = {en} } @misc{NeubauerHaubeltWankoetal.2018, author = {Neubauer, Kai and Haubelt, Christian and Wanko, Philipp and Schaub, Torsten H.}, title = {Utilizing quad-trees for efficient design space exploration with partial assignment evaluation}, series = {2018 23rd Asia and South Pacific Design Automation Conference (ASP-DAC)}, journal = {2018 23rd Asia and South Pacific Design Automation Conference (ASP-DAC)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-5090-0602-1}, issn = {2153-6961}, doi = {10.1109/ASPDAC.2018.8297362}, pages = {434 -- 439}, year = {2018}, abstract = {Recently, it has been shown that constraint-based symbolic solving techniques offer an efficient way for deciding binding and routing options in order to obtain a feasible system level implementation. In combination with various background theories, a feasibility analysis of the resulting system may already be performed on partial solutions. That is, infeasible subsets of mapping and routing options can be pruned early in the decision process, which fastens the solving accordingly. However, allowing a proper design space exploration including multi-objective optimization also requires an efficient structure for storing and managing non-dominated solutions. In this work, we propose and study the usage of the Quad-Tree data structure in the context of partial assignment evaluation during system synthesis. Out experiments show that unnecessary dominance checks can be avoided, which indicates a preference of Quad-Trees over a commonly used list-based implementation for large combinatorial optimization problems.}, language = {en} } @misc{PatilHaiderPopeetal.2011, author = {Patil, Kaustubh R. and Haider, Peter and Pope, Phillip B. and Turnbaugh, Peter J. and Morrison, Mark and Scheffer, Tobias and McHardy, Alice C.}, title = {Taxonomic metagenome sequence assignment with structured output models}, series = {Nature methods : techniques for life scientists and chemists}, volume = {8}, journal = {Nature methods : techniques for life scientists and chemists}, number = {3}, publisher = {Nature Publ. Group}, address = {London}, issn = {1548-7091}, doi = {10.1038/nmeth0311-191}, pages = {191 -- 192}, year = {2011}, language = {en} }