TY - JOUR A1 - Gebser, Martin A1 - Maratea, Marco A1 - Ricca, Francesco T1 - The Seventh Answer Set Programming Competition BT - design and results JF - Theory and practice of logic programming N2 - Answer Set Programming (ASP) is a prominent knowledge representation language with roots in logic programming and non-monotonic reasoning. Biennial ASP competitions are organized in order to furnish challenging benchmark collections and assess the advancement of the state of the art in ASP solving. In this paper, we report on the design and results of the Seventh ASP Competition, jointly organized by the University of Calabria (Italy), the University of Genova (Italy), and the University of Potsdam (Germany), in affiliation with the 14th International Conference on Logic Programming and Non-Monotonic Reasoning (LPNMR 2017). KW - Answer Set Programming KW - competition Y1 - 2019 U6 - https://doi.org/10.1017/S1471068419000061 SN - 1471-0684 SN - 1475-3081 VL - 20 IS - 2 SP - 176 EP - 204 PB - Cambridge Univ. Press CY - Cambridge [u.a.] ER - TY - JOUR A1 - Cabalar, Pedro A1 - Dieguez, Martin A1 - Schaub, Torsten H. A1 - Schuhmann, Anna T1 - Towards metric temporal answer set programming JF - Theory and practice of logic programming N2 - We elaborate upon the theoretical foundations of a metric temporal extension of Answer Set Programming. In analogy to previous extensions of ASP with constructs from Linear Temporal and Dynamic Logic, we accomplish this in the setting of the logic of Here-and-There and its non-monotonic extension, called Equilibrium Logic. More precisely, we develop our logic on the same semantic underpinnings as its predecessors and thus use a simple time domain of bounded time steps. This allows us to compare all variants in a uniform framework and ultimately combine them in a common implementation. Y1 - 2020 U6 - https://doi.org/10.1017/S1471068420000307 SN - 1471-0684 SN - 1475-3081 VL - 20 IS - 5 SP - 783 EP - 798 PB - Cambridge Univ. Press CY - Cambridge [u.a.] ER - TY - GEN A1 - Sahlmann, Kristina A1 - Clemens, Vera A1 - Nowak, Michael A1 - Schnor, Bettina T1 - MUP BT - Simplifying Secure Over-The-Air Update with MQTT for Constrained IoT Devices T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1094 KW - Internet of Things KW - security KW - firmware update KW - MQTT KW - edge computing Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-489013 SN - 1866-8372 IS - 1094 ER - TY - JOUR A1 - Sahlmann, Kristina A1 - Clemens, Vera A1 - Nowak, Michael A1 - Schnor, Bettina T1 - MUP BT - Simplifying Secure Over-The-Air Update with MQTT for Constrained IoT Devices JF - Sensors N2 - Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices. KW - Internet of Things KW - security KW - firmware update KW - MQTT KW - edge computing Y1 - 2020 U6 - https://doi.org/10.3390/s21010010 SN - 1424-8220 VL - 21 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bordihn, Henning A1 - Mitrana, Victor A1 - Paun, Andrei A1 - Paun, Mihaela T1 - Hairpin completions and reductions BT - semilinearity properties JF - Natural computing : an innovative journal bridging biosciences and computer sciences ; an international journal N2 - This paper is part of the investigation of some operations on words and languages with motivations coming from DNA biochemistry, namely three variants of hairpin completion and three variants of hairpin reduction. Since not all the hairpin completions or reductions of semilinear languages remain semilinear, we study sufficient conditions for semilinear languages to preserve their semilinearity property after applying the non-iterated hairpin completion or hairpin reduction. A similar approach is then applied to the iterated variants of these operations. Along these lines, we define the hairpin reduction root of a language and show that the hairpin reduction root of a semilinear language is not necessarily semilinear except the universal language. A few open problems are finally discussed. KW - DNA hairpin formation KW - Hairpin completions KW - Hairpin reductions KW - Semilinearity property Y1 - 2020 U6 - https://doi.org/10.1007/s11047-020-09797-0 SN - 1572-9796 VL - 20 IS - 2 SP - 193 EP - 203 PB - Springer Science + Business Media B.V. CY - Dordrecht ER - TY - JOUR A1 - Schneider, Jan Niklas A1 - Brick, Timothy R. A1 - Dziobek, Isabel T1 - Distance to the neutral face predicts arousal ratings of dynamic facial expressions in individuals with and without Autism Spectrum Disorder JF - Frontiers in psychology N2 - Arousal is one of the dimensions of core affect and frequently used to describe experienced or observed emotional states. While arousal ratings of facial expressions are collected in many studies it is not well understood how arousal is displayed in or interpreted from facial expressions. In the context of socioemotional disorders such as Autism Spectrum Disorder, this poses the question of a differential use of facial information for arousal perception. In this study, we demonstrate how automated face-tracking tools can be used to extract predictors of arousal judgments. We find moderate to strong correlations among all measures of static information on one hand and all measures of dynamic information on the other. Based on these results, we tested two measures, average distance to the neutral face and average facial movement speed, within and between neurotypical individuals (N = 401) and individuals with autism (N = 19). Distance to the neutral face was predictive of arousal in both groups. Lower mean arousal ratings were found for the autistic group, but no difference in correlation of the measures and arousal ratings could be found between groups. Results were replicated in an high autistic traits group. The findings suggest a qualitatively similar perception of arousal for individuals with and without autism. No correlations between valence ratings and any of the measures could be found, emphasizing the specificity of our tested measures. Distance and speed predictors share variability and thus speed should not be discarded as a predictor of arousal ratings. KW - arousal KW - face tracking KW - facial expression KW - autism KW - perception KW - perception differences KW - measure development Y1 - 2020 U6 - https://doi.org/10.3389/fpsyg.2020.577494 SN - 1664-1078 VL - 11 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Luther, Laura A1 - Tiberius, Victor A1 - Brem, Alexander T1 - User experience (UX) in business, management, and psychology BT - a bibliometric mapping of the current state of research JF - Multimodal technologies and interaction : open access journal N2 - User Experience (UX) describes the holistic experience of a user before, during, and after interaction with a platform, product, or service. UX adds value and attraction to their sole functionality and is therefore highly relevant for firms. The increased interest in UX has produced a vast amount of scholarly research since 1983. The research field is, therefore, complex and scattered. Conducting a bibliometric analysis, we aim at structuring the field quantitatively and rather abstractly. We employed citation analyses, co-citation analyses, and content analyses to evaluate productivity and impact of extant research. We suggest that future research should focus more on business and management related topics. KW - bibliometric analysis KW - co-citation analysis KW - co-occurrence analysis KW - citation analysis KW - user experience KW - UX Y1 - 2020 U6 - https://doi.org/10.3390/mti4020018 SN - 2414-4088 VL - 4 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Hempel, Sabrina A1 - Adolphs, Julian A1 - Landwehr, Niels A1 - Willink, Dilya A1 - Janke, David A1 - Amon, Thomas T1 - Supervised machine learning to assess methane emissions of a dairy building with natural ventilation JF - Applied Sciences N2 - A reliable quantification of greenhouse gas emissions is a basis for the development of adequate mitigation measures. Protocols for emission measurements and data analysis approaches to extrapolate to accurate annual emission values are a substantial prerequisite in this context. We systematically analyzed the benefit of supervised machine learning methods to project methane emissions from a naturally ventilated cattle building with a concrete solid floor and manure scraper located in Northern Germany. We took into account approximately 40 weeks of hourly emission measurements and compared model predictions using eight regression approaches, 27 different sampling scenarios and four measures of model accuracy. Data normalization was applied based on median and quartile range. A correlation analysis was performed to evaluate the influence of individual features. This indicated only a very weak linear relation between the methane emission and features that are typically used to predict methane emission values of naturally ventilated barns. It further highlighted the added value of including day-time and squared ambient temperature as features. The error of the predicted emission values was in general below 10%. The results from Gaussian processes, ordinary multilinear regression and neural networks were least robust. More robust results were obtained with multilinear regression with regularization, support vector machines and particularly the ensemble methods gradient boosting and random forest. The latter had the added value to be rather insensitive against the normalization procedure. In the case of multilinear regression, also the removal of not significantly linearly related variables (i.e., keeping only the day-time component) led to robust modeling results. We concluded that measurement protocols with 7 days and six measurement periods can be considered sufficient to model methane emissions from the dairy barn with solid floor with manure scraper, particularly when periods are distributed over the year with a preference for transition periods. Features should be normalized according to median and quartile range and must be carefully selected depending on the modeling approach. KW - greenhouse gas KW - on-farm evaluation KW - emission factor KW - regression KW - ensemble methods KW - gradient boosting KW - random forest KW - neural networks KW - support vector machines Y1 - 2020 U6 - https://doi.org/10.3390/app10196938 SN - 2076-3417 VL - 10 IS - 19 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dug, Mehmed A1 - Weidling, Stefan A1 - Sogomonyan, Egor A1 - Jokic, Dejan A1 - Krstić, Miloš T1 - Full error detection and correction method applied on pipelined structure using two approaches JF - Journal of circuits, systems and computers N2 - In this paper, two approaches are evaluated using the Full Error Detection and Correction (FEDC) method for a pipelined structure. The approaches are referred to as Full Duplication with Comparison (FDC) and Concurrent Checking with Parity Prediction (CCPP). Aforementioned approaches are focused on the borderline cases of FEDC method which implement Error Detection Circuit (EDC) in two manners for the purpose of protection of combinational logic to address the soft errors of unspecified duration. The FDC approach implements a full duplication of the combinational circuit, as the most complex and expensive implementation of the FEDC method, and the CCPP approach implements only the parity prediction bit, being the simplest and cheapest technique, for soft error detection. Both approaches are capable of detecting soft errors in the combinational logic, with single faults being injected into the design. On the one hand, the FDC approach managed to detect and correct all injected faults while the CCPP approach could not detect multiple faults created at the output of combinational circuit. On the other hand, the FDC approach leads to higher power consumption and area increase compared to the CCPP approach. KW - Fault tolerance KW - FEDC KW - EDC Y1 - 2020 U6 - https://doi.org/10.1142/S0218126620502187 SN - 0218-1266 SN - 1793-6454 VL - 29 IS - 13 PB - World Scientific CY - Singapore ER - TY - JOUR A1 - Li, Yuanqing A1 - Breitenreiter, Anselm A1 - Andjelkovic, Marko A1 - Chen, Junchao A1 - Babic, Milan A1 - Krstić, Miloš T1 - Double cell upsets mitigation through triple modular redundancy JF - Microelectronics Journal N2 - A triple modular redundancy (TMR) based design technique for double cell upsets (DCUs) mitigation is investigated in this paper. This technique adds three extra self-voter circuits into a traditional TMR structure to enable the enhanced error correction capability. Fault-injection simulations show that the soft error rate (SER) of the proposed technique is lower than 3% of that of TMR. The implementation of this proposed technique is compatible with the automatic digital design flow, and its applicability and performance are evaluated on an FIFO circuit. KW - Triple modular redundancy (TMR) KW - Double cell upsets (DCUs) Y1 - 2019 U6 - https://doi.org/10.1016/j.mejo.2019.104683 SN - 0026-2692 SN - 1879-2391 VL - 96 PB - Elsevier CY - Oxford ER -