Efficient compliance checking of RDF data

Automated compliance checking, i.e. the task of automatically assessing whether states of affairs comply with normative systems, has recently received a lot of attention from the scientific community, also as a consequence of the increasing investments in Artificial Intelligence technologies for the legal domain (LegalTech). The authors of this paper deem as crucial the research and implementation of compliance checkers that can directly process data in RDF format, as nowadays more and more (big) data in this format are becoming available worldwide, across a multitude of different domains. Among the automated technologies that have been used in recent literature, to the best of our knowledge, only two of them have been evaluated with input states of affairs encoded in RDF format. This paper formalizes a selected use case in these two technologies and compares the implementations, also in terms of simulations with respect to shared synthetic datasets

Specifying and Exploiting Non-Monotonic Domain-Specific Declarative Heuristics in Answer Set Programming

Domain-specific heuristics are an essential technique for solving combinatorial problems efficiently. Current approaches to integrate domain-specific heuristics with Answer Set Programming (ASP) are unsatisfactory when dealing with heuristics that are specified non-monotonically on the basis of partial assignments. Such heuristics frequently occur in practice, for example, when picking an item that has not yet been placed in bin packing. Therefore, we present novel syntax and semantics for declarative specifications of domain-specific heuristics in ASP. Our approach supports heuristic statements that depend on the partial assignment maintained during solving, which has not been possible before. We provide an implementation in ALPHA that makes ALPHA the first lazy-grounding ASP system to support declaratively specified domain-specific heuristics. Two practical example domains are used to demonstrate the benefits of our proposal. Additionally, we use our approach to implement informed} search with A*, which is tackled within ASP for the first time. A* is applied to two further search problems. The experiments confirm that combining lazy-grounding ASP solving and our novel heuristics can be vital for solving industrial-size problems

Extending Answer Set Programming with Rational Numbers

Answer Set Programming (ASP) is a widely used declarative programming paradigm that has shown great potential in solving complex computational problems. However, the inability to natively support non-integer arithmetic has been highlighted as a major drawback in real-world applications. This feature is crucial to accurately model and manage real-world data and information as emerged in various contexts, such as the smooth movement of video game characters, the 3D movement of mechanical arms, and data streamed by sensors. Nevertheless, extending ASP in this direction, without affecting its declarative nature and its well-defined semantics, poses non-trivial challenges; thus, no ASP system is able to reason natively with non-integer domains. Indeed, the widespread floating-point arithmetic is not applicable to the ASP case, as the reproducibility of results cannot be guaranteed and the semantics of an ASP program would not be uniquely and declaratively determined, regardless of the employed machine or solver. To overcome such limitations and in the realm of pure ASP, this paper proposes an extension of ASP in which non-integers are approximated to rational numbers, fully granting reproducibility and declarativity. We provide a well-defined semantics for the ASP-Core-2 standard extended with rational numbers and an implementation thereof. We hope this work could serve as a stepping stone towards a more expressive and versatile ASP language that can handle a broader range of real-world problems

Automated Support for Creating Experimental Setups in Material Sciences

Na área de conservação e restauro, o interesse na investigação de fontes escritas históricas tem vindo a crescer nos últimos anos, no entanto, estes estudos raramente exploram a evolução de materiais de pintura e a reprodução de receitas. As receitas são conjuntos de instruções para preparar materiais (vidro, pigmentos, esmaltes) e são reproduzidas com o objetivo de avaliar os métodos utilizados, bem como de determinar as causas da deterioração dos materiais. Na unidade de investigação VICARTE - Vidro e Cerâmica para as Artes, no âmbito da investigação da linha temática de estudos do património cultural, investigam-se estas receitas históricas através da sua reprodução, o que requer planear experiências tendo em consideração o material e os recursos disponíveis. No entanto, o número elevado de possíveis combinações de utilização destes recursos, tornam a realização do planeamento de forma manual complicada e morosa. Nesta dissertação foi desenvolvida uma solução para este problema, em colaboração com a unidade de investigação VICARTE, recorrendo ao uso de Answer Set Programming de forma a criar horários para a realização das experiências, otimizando os recursos dispo- níveis. Como resultado foi desenvolvida uma aplicação que facilita a criação dos mesmos.In the field of conservation and restoration, interest in the investigation of historical written sources has been growing in recent years, however, these studies rarely explore the evolution of painting materials and the reproduction of recipes. The recipes are a set of instructions for preparing materials (glass, pigments, enamels) and are reproduced in order to evaluate the methods used, as well as to determine the causes of deterioration of the materials. In the research unit VICARTE - Glass and Ceramics for the Arts, within the scope of research in the thematic line of studies of cultural heritage, these historical recipes are investigated through their reproduction, which requires planning experiments taking into account the material and resources available. However, the high number of possible combinations for the use of these resources makes manual planning complicated and time consuming. In this dissertation, was developed a solution to this problem, in collaboration with the research unit VICARTE, using Answer Set Programming in order to create schedules for performing the experiments, optimizing the available resources. As a result, was developed an application that facilitates the creation of these

Evaluation Techniques and Systems for Answer Set Programming: a Survey

Answer set programming (ASP) is a prominent knowledge representation and reasoning paradigm that found both industrial and scientific applications. The success of ASP is due to the combination of two factors: a rich modeling language and the availability of efficient ASP implementations. In this paper we trace the history of ASP systems, describing the key evaluation techniques and their implementation in actual tools