Description logics

This book constitutes the refereed proceedings of the 7th International Semantic Web Conference, ISWC 2008, held in Karlsruhe, Germany, during October 26-30, 2008. The volume contains 43 revised full research papers selected from a total of 261 submissions, of which an additional 3 papers were referred to the semantic Web in-use track; 11 papers out of 26 submissions to the semantic Web in-use track, and 7 papers and 12 posters accepted out of 39 submissions to the doctorial consortium. The topics covered in the research track ...

Existing approaches for querying OWL DL do either only operate on syntactic constructs without taking into account the semantics of OWL or do only have a restricted access to the T-Box. We present SAIQL, the novel Schema And Instance Query Language for OWL DL, that is well suited for ontology extraction. We describe its syntax and explain a basic evaluation strategy. We illustrate the use of SAIQL with an example for ontology extraction and re-use.

For a number of problems, such as ontology learning or image labeling, we need to handle uncertainty and inconsistencies in an appropriate way. Fuzzy and Probabilistic Description Logics are the two major approaches for performing reasoning with uncertainty in Description Logics, but modeling problems such as image labeling still remains difficult and handling inconsistencies is only supported to a limited extent. In this paper, we propose Max-DL-SAT and Weighted Max-DL-SAT as new reasoning services for Description Logics knowledge bases, which applies the idea behind Weighted Max-SAT to Description Logics and leads to a more intuitive representation of certain problems. It supports handling of uncertainty and inconsistencies. The contribution of this paper is threefold: We define a novel reasoning service on Description Logics knowledge bases, introduce an algorithm for solving such problems, and show the application of it to the problem of image labeling.

A Software Product Line (SPL) is a set of programs that are developed as a whole and share a set of common features. Product line's variability is typically specified using problem space models (i.e., feature models), solution space models that specify the realization of functionality and mapping models that link problem and solution space artifacts. In this paper, we consider this concept in the scope of families of business processes, whose specificity is that the solution space is defined with business process models. Solution space models are typically specified as model templates, and thus in the rest of the paper we will refer to business process model templates. While the previous research tackled the concepts of families of business processes, there have been very limited research on their validation.

Existing approaches for querying OWL DL do either only operate on syntactic constructs without taking into account the semantics of OWL or do only have a restricted access to the T-Box. We present SAIQL, the novel Schema And Instance Query Language for OWL DL, that is well suited for ontology extraction. We describe its syntax and explain a basic evaluation

Efficient resource retrieval is a crucial issue, particularly in the context of Semantic Web, since forms of reasoning are used for answering requests. Resources are retrieved by performing a match test between each resource description and the query. This approach becomes inefficient with the increase of available resources. We propose a method for improving the retrieval process by constructing a tree index through a new conceptual clustering method for resources expressed in Web ontology languages. In the index, the available resource descriptions are located at the leaf nodes, while inner nodes represent intensional descriptions (generalizations) of their child nodes. The match process is executed by following the tree branches whose nodes satisfy the query. Query answering time may be strongly improved as the steps may be O(log n).

For a number of problems, such as ontology learning or image labeling, we need to handle uncertainty and inconsistencies in an appropriate way. Fuzzy and Probabilistic Description Logics are the two major approaches for performing reasoning with uncertainty in Description Logics, but modeling problems such as image labeling still remains difficult and handling inconsistencies is only supported to a limited extent. In this paper, we propose Max-DL-SAT and Weighted Max-DL-SAT as new reasoning services for Description Logics knowledge bases, which applies the idea behind Weighted Max-SAT to Description Logics and leads to a more intuitive representation of certain problems. It supports handling of uncertainty and inconsistencies. The contribution of this paper is threefold: We define a novel reasoning service on Description Logics knowledge bases, introduce an algorithm for solving such problems, and show the application of it to the problem of image labeling.

Currently computers are changing from single isolated devices to entry points into a worldwide network of information exchange and business transactions. Therefore, support in the exchange of data, information, and knowledge is becoming the key issue in computer technology today. Ontologies provide a shared and common understanding of a domain that can be communicated between people and across application systems. Ontologies will play a major role in supporting information exchange processes in various areas. A ...

Introduction The problem of revising a description logic-based ontology (called DL ontology) is closely related to the problem of belief revision which has been widely discussed in the literature. Among early works on belief revision, the AGM theory (Alchourron et al., 1985) introduced intuitive and plausible constraints (namely AGM postulates) which should be satisfied by any rational belief revision operator. However, it is not trivial to adapt belief revision operators to DLs because DLs have their own features (Flouris et al., 2005) (Qi and Yang, 2008). One main difficult for such revision is that DL ontologies often incur infinitely many models. To address this issue, we propose a finite set of finite structures, namely a set MT(O) of completion trees, for characterizing a possibly infinite set of models of an ontology O. Then, we define a distance over a set of completion trees. This distance allows one to determine how far an ontology is from another one. Another problem our ...

DRAOn is a distributed reasoner which offers inference services for a network of OWL ontologies correlated by alignments. Reasoning with such networks of ontologies depends on the semantics we define for alignments with respect to ontologies. DRAOn supports two semantics for a network of ontologies: the standard Description Logics (DL) semantics for non-distributed reasoning, and the Integrated Distributed Description Logics (IDDL) semantics for distributed reasoning. Unlike the DL semantics where alignments are considered as inter-ontology axioms, the IDDL semantics interprets alignments as correspondences enabling to propagate non-emptiness (always satisfiable) and unsatisfiability of atomic concepts from an ontology to another one. Consequently, this makes distributed reasoning for a network of ontologies possible since consistency of the whole network can be decided from consistency of each ontology with axioms built from alignments such that these axioms ensure just necessary propagations of knowledge.

In this paper, we propose an EXPSPACE tableaux-based algorithm for SHOIQ. The construction of this algorithm is founded on the standard tableauxbased method for SHOIQ and the technique used for designing a NEXPTIME algorithm for the two-variable fragment of first-order logic with counting quantifiers C 2 .

Modern organizations increasingly evolve through distributed and collaborative units. Combined with the widespread use of Internet-based information resources, this extends the boundaries of organizational memory and challenges traditional, centralized information systems. These systems struggle to support the dynamic needs of modern knowledge management.

Initially, the Internet was welcomed as a powerful source of information. However, the overwhelming volume quickly led to cognitive overload, hindering rather than helping decision-making. Technologies like the Semantic Web and Web services attempt to address these challenges, but they often fall short in dealing with the distributed and heterogeneous nature of modern organizational memory.

What’s needed is a user-centered system that embraces this complexity and supports the natural evolution of knowledge processes. To avoid past limitations, Prince proposed a federator model for global knowledge management, which aligns well with the multi-agent paradigm. Multi-agent systems are inherently suited to distributed environments and allow modular evolution by adding agents to meet future needs.

Prince emphasizes using communicational gateways at physical, symbolic, and semantic levels to ensure coherence across the system. The JADE (Java Agent DEvelopment Framework) platform supports this with standardized agent communication, and Semantic Web technologies enhance access to shared knowledge through ontologies—structured models of concepts and relationships. Tools like Protégé-2000 help create and manage these ontologies.

Our proposed system, COSMO (Connaissances Organisées par un Système Multi-agents à l’aide d’Ontologies), integrates JADE and Protégé-2000 as core components. Using the PASSI methodology, we define agent behavior in AUML, allowing automatic generation of agents for JADE. COSMO’s agents act from the user’s perspective, navigating organizational memory and the Semantic Web using mobile, semi-autonomous behaviors.

Users can monitor, assign, and manage agents. COSMO includes six key agents—CommunityAgent, OntoTranslatorAgent, ServiceFinder, ServicesAgent, SmartAgent, and UserAgentUI—that collaborate to support distributed knowledge management effectively.

Keywords: COSMO, multi-agent system, JADE, ontologies, Protégé-2000, knowledge management, Semantic Web.

In order to deal with the Ontology Change problem and considering an environment where Description Logics (DLs) are used to describe ontologies, the question of how to integrate distributed ontologies appears to be in touch with Belief Revision since DL terminologies may define same concept descriptions of a not necessarily same world model. A possible alternative to reason about these concepts is to generate unique concept descriptions in a different terminology. This new terminology needs to be consistently created, trying to deal with the minimal change problem, and moreover, yielding a non-monotonic layer to express ontological knowledge in order to be further updated with new distributed ontologies.

Ontology evaluation is an important issue that must be addressed during the lifecycle of an ontology because it assures that the ontology reflects the desired requirements during selection, design, population, evolution, usage, or other processes of the ontology lifecycle. Ontology evaluation aims at assessing the quality and the adequacy of an ontology from the point of view of a particular predefined criterion, for use in a specific context, for a specific purpose. Here, we demonstrate that evaluation is an important issue for ontology evolution. To capture the different nature of evaluation and evolution criteria, we use a tool (S-OntoEval) aiming at assessing ontology quality by implementing existing quality metrics that draw upon semiotic theory. An evaluation of the SWIntO ontology of the SmartWeb project shows its controlled evolution by quality measurement and improvement.

The administrator of current IT environments is facing a continuous increase in the complexity that s/he needs to handle. S/he can be compared to a power jet pilot sitting in front of a console with a plenty of gouges, leds, counters, each of them measuring or showing a particular part of the overall aircraft status. The pilot looks to all these indications, correlate each other these data sources, provide them a context (the air craft is landing, is taking off, and so forth) and, on the light of his knowledge and experience, he can ...

In this paper, optimum decomposition of belief networks is discussed. Some methods of decom position are examined and a new method -the method of Minimum Total Number of States (MTNS)-is proposed. The problem of optimum belief network decomposition under our frame work, as under all the other frameworks, is shown to be NP-hard. According to the computational complexity analysis, an algorithm of belief net work decomposition is proposed in (Wen, 1989b) based on simulated annealing. • How can we decompose the space into sub-

Mapping between ontologies and relational databases is a necessity in realising the Semantic Web vision. Most of the work concerning this topic has either (1) extracted OWL schemas using a limited range of OWL modelling constructs from relational schemas, or (2) extracted relational schemas from OWL schemas, that represent the OWL schemas as much as possible. By contrast, we propose a general framework that maps between relational databases and schemas expressed in OWL 2. In particular, we regard the transformation from databases to ontologies as being a two-phase process. Firstly, to convert the relational schemas into OWL schemas, and then to enrich the OWL schemas with highly expressive axioms, based on analysing the schemas and the data in the databases. Testing our data analysis heuristics on a number of databases, show that they produce OWL schemas, that include more semantic information than found in their respective relational schemas.

SQOWL2 is a compiler which allows an RDBMS to support sound reasoning of SROIQ(D) description logics, by implementing ontologies expressed in the OWL 2 DL language as a combination of tables and triggers in the RDBMS. The reasoning process is divided into two phases of classification of the T-Box and type inference of the A-Box. SQOWL2 establishes a relational schema based on classification completed using the Pellet reasoner, and performs type inference by using SQL triggers. SQOWL2 supports type inference over all OWL 2 DL constructs, and supports a more conventional relational schemas, rather than naively mapping OWL classes and properties to relational tables with one and two columns. Moreover, SQOWL2 is a transactional reasoning system (with full ACID properties), since the results of reasoning are available within the same transaction as that in which the base data of the reasoning was inserted.

This paper introduces the Protégé plugin uDecide. With the help of uDecide it is possible to solve multi-attribute decision making problems encoded in a straight forward extension of standard Description Logics. The formalism allows to specify background knowledge in terms of an ontology, while each attribute is represented as a weighted class expression. On top of such an approach one can compute the best choice (or the best k-choices) taking background knowledge into account in the appropriate way. We show how to implement the approach on top of existing semantic web technologies and demonstrate its benefits with the help of an interesting use case that illustrates how to convert an existing web resource into an expert system with the help of uDecide.

Research on database design at PUC-Rio dates back to the late seventies and covers a broad range of topics, from the early development of the relational model to recent applications of semiotic concepts to the design and specification of information systems. This paper briefly reviews some of the major contributions of the group, from the perspective of the authors. It organizes the contributions according to the data model or to the underlying disciplines that they are based on. Within each section, the presentation follows a chronological order as much as possible.

This paper proposes the use of description logics as a representational framework for learning composite concepts. Description logics are restricted variants of first-order logic providing a form of logical bias that dates back to semantic networks. Some recent work investigates concept learning in the context of these formalisms. Also, having recognized the importance of part-whole hierarchies in commonsense reasoning, researchers have started to incorporate part-of reasoning into description logics. In our approach we represent composite concepts in such a formalism. On one hand we have a relatively rich representation language with an infinite space of possible concepts. On the other hand we have special constructs for handling part-of relations that can be used in the learning algorithm to reduce the overall search space.

Embedding models have been successfully exploited for predictive tasks on Knowledge Graphs (KGs). We propose TRANSROWL-HRS, which aims at making KG embeddings more semantically aware by exploiting the intended semantics in the KG. The method exploits schema axioms to encode knowledge that is observed as well as derived by reasoning. More knowledge is further exploited by relying on a successive hierarchical clustering process applied to relations, to make use of the several semantic meanings that the very same relation may have. An experimental evaluation on link prediction and triple classification tasks proves the improvement yielded by the proposed approach (coupled with different optimizers) compared to some baseline models.

The Wine Agent is a demonstration system that uses an underlying domain ontology to provide suitable wines for a given meal. In doing so it serves as a testbed, not only for the logical domain description, but additionally for emerging Semantic Web technologies that process, infer, justify, and execute the pairings. Specifically, it combines the the DAML+ OIL and OWL Web-based description logics with the JTP theorem prover. The resulting knowledge base can be queried remotely via the DQL query language. ...

Parametrized logic programs are very expressive logic programs that generalize normal logic programs under the stable model semantics, by allowing complex formulas of a parameter logic to appear in the body and head of rules. In this paper we explore the use of description logics as parameter logics, and show the expressivity of this framework for combining rules and ontologies. Introduction Parametrized logic programming [Goncalves and Alferes, 2010] was introduced as an extension of answer set programming [Gelfond and Lifschitz, 1988] with the motivation of providing a meaning to theories combining both logic programming connectives with other logical connectives, and allowing complex formulas using these connectives to appear in the head and body of a rule. The main idea is to fix a monotonic logic L, called the parameter logic, and build up logic programs using formulas of L instead of just atoms. The obtained parametrized logic programs have, therefore, the same structure of no...

Selectively forgetting information while preserving what matters the most is becoming an increasingly important issue in many areas, including in knowledge representation and reasoning. Depending on the application at hand, forgetting operators are defined to obey different sets of desirable properties. Of the myriad of desirable properties discussed in the context of forgetting in Answer Set Programming, strong persistence, which imposes certain conditions on the correspondence between the answer sets of the program preand post-forgetting, and a certain independence from non-forgotten atoms, seems to best capture its essence, and be desirable in general. However, it has remained an open problem whether it is always possible to forget a set of atoms from a program while obeying strong persistence. In this paper, after showing that it is not always possible to forget a set of atoms from a program while obeying this property, we move forward and precisely characterise what can and can...

We address the problem of finding high-level explanations for concept subsumption w.r.t. combinations of EL (resp. EL) CBoxes. Our goal is to find explanations for concept subsumptions in such combinations of CBoxes which contain only symbols (concept names and role names) that are common to the CBoxes. For this, we use the encoding of TBox subsumption as a uniform word problem in classes of semilattices with monotone operators for EL and the ≤-interpolation property in these classes of algebras, as well as extensions to these results in the presence of role inclusions. For computing the ≤-interpolating terms we use a translation to propositional logic and methods for computing Craig interpolants in propositional logic.

This paper investigates the possibility of exploiting formal analysis tools developed in the database field for the purpose of studying the expressive power of description logics augmented with rule-based query languages. We report a preliminary analysis on the expressive power of such hybrid languages. Two specific languages coupling a terminological component with Horn rules are considered. It is shown that: (1) the former language defines all database collections expressed by skolemized universally quantified second order formulae where quantified predicates are monadic, and (2) the latter language defines all database collections expressed by skolemized universally quantified second order formulae where quantified predicates are dyadic or monadic.

Using data samples of 102 × 10 6 Υ(1S) and 158 × 10 6 Υ(2S) events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays Υ(1S, 2S) → J/ψ(ψ ′ ) + X, where X = η c , χ cJ (J = 0, 1, 2), η c (2S), X(3940), and X(4160). No significant signal is observed in the spectra of the mass recoiling against the reconstructed J/ψ or ψ ′ except for the evidence of χ c1 production with a significance of 4.6σ for Υ(1S) → J/ψ + χ c1 . The measured branching fraction B(Υ(1S) → J/ψ + χ c1 ) is (3.90 ± 1.21(stat.) ± 0.23(syst.)) × 10 -6 . The 90% confidence level upper limits on the branching fractions of the other modes having a significance of less than 3σ are determined. These results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.

EU-IST Integrated Project (IP) IST-2003-506826 SEKT Deliverable D3.5.1(WP3.5) In this document, we propose a framework for reasoning with multi-version ontology, in which a temporal logic is developed to serve as its semantic foundation. We show that the temporal logic approach can provide a solid semantic foundation which can support various requirements on multi-version ontology reasoning. We have implemented the prototype of MORE (Multi-version Ontology REasoner), which is based on the proposed framework. In this document, we present the design of the interfaces for MORE, and discuss its implementation.

EU-IST Integrated Project (IP) IST-2003-506826 SEKT Deliverable D3.5.1(WP3.5) In this document, we propose a framework for reasoning with multi-version ontology, in which a temporal logic is developed to serve as its semantic foundation. We show that the temporal logic approach can provide a solid semantic foundation which can support various requirements on multi-version ontology reasoning. We have implemented the prototype of MORE (Multi-version Ontology REasoner), which is based on the proposed framework. In this document, we present the design of the interfaces for MORE, and discuss its implementation.

In response to changing requirements and other environmental influences, software systems are increasingly developed incrementally. Successful implementation of new features in existing software is often difficult, whilst many software systems simply 'break'when features are introduced. Size and complexity of modern software, poor software design, and lack of appropriate tools are some of the factors that often confound the issue. In this paper, we report on a successful industrial experience of evolving a feature-rich ...

The European General Data Protection Regulation (GDPR) calls for technical and organizational measures to support its implementation. Towards this end, the SPE-CIAL H2020 project aims to provide a set of tools that can be used by data controllers and processors to automatically check if personal data processing and sharing complies with the obligations set forth in the GDPR. The primary contributions of the project include: (i) a policy language that can be used to express consent, business policies, and regulatory obligations; and (ii) two different approaches to automated compliance checking that can be used to demonstrate that data processing performed by data controllers / processors complies with consent provided by data subjects, and business processes comply with regulatory obligations set forth in the GDPR.

We present measurements of the decays B + → X(3872)K + and B 0 → X(3872)K 0 with X(3872) → J/ψ π + π -. The data sample used, collected with the BABAR detector at the PEP-II e + e -asymmetric-energy storage ring, corresponds to 455 × 10 6 B B pairs. Branching fraction measurements of B(B + → X(3872)K + ) × B(X(3872) → J/ψ π + π -) = (8.4 ± 1.5 ± 0.7) × 10 -6 and B(B 0 → X(3872)K 0 ) × B(X(3872) → J/ψ π + π -) = (3.5 ± 1.9 ± 0.4) × 10 -6 are obtained. We set an upper limit on the natural width of the X(3872) of Γ < 3.3 MeV/c 2 at the 90% confidence level.

This paper deals with the description of the evolution of the understanding of the history of a particular world. We have particular interest in describing certain problems that occur in database systems due to updates. For this purpose, we introduce a two-dimensional temporal logic as a formalism which enables the description of both the history and the evolution of the beliefs about the history. The historical dimension describes the history of the world according to a certain belief. The belief dimension describes the evolution of those beliefs. The historical dimension is then associated with an historical database, and transactions in the database are associated with changes in belief. Besides describing the history of the world, the database system can also execute temporal speci cations in the form of temporal actions. The two-dimensional formalism is used to describe the e ects of updates in the execution of temporal actions. Those descriptions are then taken as speci cations for a database system and their implementation is discussed.

Given two graphs G and H and a function f ⊂ V (G) × V (H), Hedetniemi [9] defined the function graph Gf H by Whenever G ∼ = H, the function graph was called a functigraph by Chen, Ferrero, Gera and Yi . A function graph is a generalization of the α-permutation graph introduced by Chartrand and Harary . The independence number of a graph is the size of a largest set of mutually non-adjacent vertices. In this paper, we study independence number in function graphs. In particular, we give a lower bound in terms of the order and the chromatic number, which improves on some elementary results and has a number of interesting corollaries.

Naremore (2006) , într-un articol academic despre estetica grotescului în filmele lui Kubrick, a făcut o trecere în revistă a folosirii termenului „grotesc” (ca întindere, aproape jumătate din articolul său). A început cu prima sa folosire, în Roma, în jurul anului 1500. La acea vreme au fost descoperite niște motive decorative antice care cuprindeau imagini precum copaci în care cresc capete de oameni. Ultima folosire a termenului luată în calcul de autor este analiza termenului în două lucrări de critică a grotescului din anii 1950-1960 .

Conceptual models are an important repository for knowledge in companies and public institutions. The retrieval of this knowledge can prepare reorganisations projects and support IT investment decisions. However, so far this information source has hardly been utilized in automated analyses. We argue that if modelling languages are endowed with specific characteristics the resulting models can be analysed in an automatic manner. We formally show that with such languages: (1) type, synonym, homonym, and abstraction conflicts are eliminated as well as (2) the identification of semantically equivalent model elements can be traced back to finding syntactic ones.

National audienceL&#39;automatisationetlasupervisiondessystèmespervasifsestàl&#39;heure actuelle principalement basée sur l&#39;utilisation massive de capteurs distribués dans l&#39;environnement. Dans cet article, nous proposons un modèle de super- vision d&#39;interactions basé sur l&#39;analyse sémantique des logs domotiques (com- mandes émises par l&#39;utilisateur), visant à limiter l&#39;utilisation de ces capteurs : le principe est d&#39;utiliser des outils d&#39;inférences avancés, afin de déduire les in- formations habituellement captées. Pour cela, une ontologie, automatiquement dérivée d&#39;un processus dirigé par les modèles, définit les interactions utilisateur- système. L&#39;utilisation d&#39;un système de règles permet ensuite d&#39;inférer des infor- mations sur la localisation et l&#39;intention de l&#39;utilisateur, dans le but de réaliser du monitoring et de proposer des services domotiques adaptés

Combinatorial creativity combines existing concepts in a novel way in order to produce new concepts. For example, we can imagine jewelry that measures blood pressure. For this, we would combine the concept of jewelry with the capabilities of medical devices. Combinatorial creativity can be used to develop new business ideas, to find plots for books or movies, or simply to disrupt conventional thinking. In this paper, we propose a formal language for combinatorial creativity, based on description logics. We show that our language can be used to model existing inventions and (to a limited degree) to generate new concepts. This report complements our paper at the ISWC 2016 conference [22].

Acyclic conjunctive queries form a polyno-mially evaluable fragment of definite non-recursive first-order Horn clauses. Labeled graphs, a special class of relational struc-tures, provide a natural way for represent-ing chemical compounds. We propose an al-gorithm specific to ...

Over the past years, there has been a resurgence of Datalog-based systems in the database community as well as in industry. In this context, it has been recognized that to handle the complex knowledge-based scenarios encountered today, such as reasoning over large knowledge graphs, Datalog has to be extended with features such as existential quantification. Yet, Datalog-based reasoning in the presence of existential quantification is in general undecidable. Many efforts have been made to define decidable fragments. Warded Datalog+/-is a very promising one, as it captures PTIME complexity while allowing ontological reasoning. Yet so far, no implementation of Warded Datalog+/-was available. In this paper we present the Vadalog system, a Datalog-based system for performing complex logic reasoning tasks, such as those required in advanced knowledge graphs. The Vadalog system is Oxford's contribution to the VADA research programme, a joint effort of the universities of Oxford, Manchester and Edinburgh and around 20 industrial partners. As the main contribution of this paper, we illustrate the first implementation of Warded Datalog+/-, a high-performance Datalog+/-system utilizing an aggressive termination control strategy. We also provide a comprehensive experimental evaluation.

A crucial task in Knowledge Representation is answering queries posed over a knowledge base, represented as a set of facts plus a set of rules. In this paper we address the problem of answering conjunctive queries posed over knowledge bases where rules are an extension of Datalog rules, called Datalog ∃ rules, that may have existentially quantified variables in the head; this kind of rules are traditionally called tuple-generating dependencies (TGDs) in the database literature, but they are broadly used in description logics and in ontological reasoning. In this setting, the chase algorithm is an important tool for query answering. So far, most of the research has concentrated on cases where the chase terminates. We define and study large classes of TGDs under which the query evaluation problems remain decidable even in case the chase does not terminate. We provide tight complexity bounds for such cases. Our results immediately extend to query containment.

We present DEGARI (Dynamic Emotion Generator And ReclassIfier), an explainable system for emotion attribution and recommendation. This system relies on a recently introduced commonsense reasoning framework, the T CL logic, which is based on a human-like procedure for the automatic generation of novel concepts in a Description Logics knowledge base. Starting from an ontological formalization of emotions based on the Plutchik model, known as ArsEmotica, the system exploits the logic T CL to automatically generate novel commonsense semantic representations of compound emotions (e.g. Love as derived from the combination of Joy and Trust according to Plutchik). The generated emotions correspond to prototypes, i.e. commonsense representations of given concepts, and have been used to reclassify emotion-related contents in a variety of artistic domains, ranging from art datasets to the editorial contents available in RaiPlay, the online platform of RAI Radiotelevisione Italiana (the Italian public broadcasting company). We show how the reported results (evaluated in the light of the obtained reclassifications, the user ratings assigned to such reclassifications, and their explainability) are encouraging, and pave the way to many further research directions.

The aim of this paper is to show the role that Knowledge Representation can play in the research of artisanal fisheries. In particular we concentrate on the epistemological and technological adequacy of implementations of Description Logics to represent fishers' ecological knowledge, so contributing to address some open methodological questions about its collection and use.

In this paper, we analyze the values and characteristics of fishers&#x27; ecological knowledge (FEK). Using the artisanal coastal fisheries of Galicia as a case study, we present the objectives of the integration of FEK in fisheries biology and management and propose a ...