Recursive Online Enumeration of All Minimal Unsatisfiable Subsets

In various areas of computer science, we deal with a set of constraints to be satisfied. If the constraints cannot be satisfied simultaneously, it is desirable to identify the core problems among them. Such cores are called minimal unsatisfiable subsets (MUSes). The more MUSes are identified, the more information about the conflicts among the constraints is obtained. However, a full enumeration of all MUSes is in general intractable due to the large number (even exponential) of possible conflicts. Moreover, to identify MUSes algorithms must test sets of constraints for their simultaneous satisfiabilty. The type of the test depends on the application domains. The complexity of tests can be extremely high especially for domains like temporal logics, model checking, or SMT. In this paper, we propose a recursive algorithm that identifies MUSes in an online manner (i.e., one by one) and can be terminated at any time. The key feature of our algorithm is that it minimizes the number of satisfiability tests and thus speeds up the computation. The algorithm is applicable to an arbitrary constraint domain and its effectiveness demonstrates itself especially in domains with expensive satisfiability checks. We benchmark our algorithm against state of the art algorithm on Boolean and SMT constraint domains and demonstrate that our algorithm really requires less satisfiability tests and consequently finds more MUSes in given time limits

Dataset of 15-minute values of active and reactive power consumption of 1000 households during single year

The dataset of average 15 minute values of active and reactive energy consumption of 1000 individual anonymized households, mix of rural and urban, during year 2016. Data were collected using Intelligent measuring systems (IMS) power meters installed at Point of Consumptions of 1000 households. All households are situated in the Slovak Republic. Data were provided for anonymous use and publishing by local Distribution system operator (DSO). All households are connected to low voltage (LV) 0.4 kV network.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Dataset of 15-minute values of active and reactive power consumption of 1000 households during single year

The dataset of average 15 minute values of active and reactive energy consumption of 1000 individual anonymized households, mix of rural and urban, during year 2016. Data were collected using Intelligent measuring systems (IMS) power meters installed at Point of Consumptions of 1000 households. All households are situated in the Slovak Republic. Data were provided for anonymous use and publishing by local Distribution system operator (DSO). All households are connected to low voltage (LV) 0.4 kV network.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Counting Minimal Unsatisfiable Subsets

10.1007/978-3-030-81688-9_15Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)12760 LNCS313-33

Specification Quality Metrics Based on Mutation and Inductive Incremental Model Checking

International audienceWhen using formal verification on Simulink or SCADE models , an important question about their certification is how well the specified properties cover the entire model. A method using unsatisfiable cores and inductive model checking called IVC (Inductive Validity Cores) has been recently proposed within modern SMT-based model checkers such as JKind. The IVC algorithm determines a minimal set of model elements necessary to establish a proof and gives back the traceability to the design elements (lines of code) necessary for the proof. These metrics are interesting but are rather coarse grain for certification purposes. In this paper, we propose to use mutation combined with incremental inductive model checking to give more precision and quality to the trace-ability process and look inside the lines of code. Our algorithm, based on the result of IVC, mutates the source code to determine which parts inside a line of code have an impact on the properties (killed mutants) and which parts have no impact on the properties (survived mutants). Furthermore , using the incremental feature present in modern SMT-solvers, we observe that mutation can scale up to industrial models. We demonstrate the metrics first on a simple example, then on a complex industrial program and on the JKind benchmark

Hemispheric sunspot numbers

From sunspot drawings provided by the Kanzelhöhe Solar Observatory, Austria, and the Skalnaté Pleso Observatory, Slovak Republic, we extracted a data catalogue of hemispheric Sunspot Numbers covering the time span 1945-2004. The validated catalogue includes daily, monthly-mean, and smoothed-monthly relative sunspot numbers for the northern and southern hemispheres separately and is available for scientific use. These data we then investigated with respect to north-south asymmetries for almost 6 entire solar cycles (Nos. 18-23). For all the cycles studied, we found that the asymmetry based on the absolute asymmetry index is enhanced near the cycle maximum, which contradicts to previous results that are based on the normalized asymmetry index. Moreover, the weak magnetic interdependence between the two solar hemispheres is confirmed by their self-contained evolution during a cycle. For the time span 1945-2004, we found that the cycle maxima and also the declining and increasing phases are clearly shifted, whereas the minima seem to be in phase for both hemispheres. The asymmetric behavior reveals no obvious connection to either the sunspot cycle period of ~11- or the magnetic cycle of ~22-years. The most striking excess of activity is observed for the northern hemisphere in cycles 19 and 20

Reasoning About Strong Inconsistency in ASP

International audienceThe last decade has witnessed remarkable improvements in the analysis of inconsistent formulas, namely in the case of Boolean Satisfiability (SAT) formulas. However, these successes have been restricted to monotonic logics. Recent work proposed the notion of strong inconsistency for a number of non-monotonic logics, including Answer Set Programming (ASP). This paper shows how algorithms for reasoning about inconsistency in monotonic logics can be extended to the case of ASP programs, in the concrete case of strong inconsistency. Initial experimental results illustrate the potential of the proposed approach