Semantic Matchmaking of Web Resources with Local Closed-World Reasoning

Ontology languages like OWL allow for semantically rich annotation of resources (e.g., products advertised at on-line electronic marketplaces). The description logic (DL) formalism underlying OWL provides reasoning techniques that perform match-making on such annotations. This paper identifies peculiarities in the use of DL inferences for matchmaking that derive from OWL\u27s open-world semantics, analyzes local closed-world reasoning for its applicability to matchmaking, and investigates the suitability of two nonmonotonic extensions to DL, autoepistemic DLs and DLs with circumscription, for local closed-world reasoning in the matchmaking context. An elaborate example of an electronic marketplace for PC product catalogs from the e-commerce domain demonstrates how these formalisms can be used to realize such scenarios

Legal methods for resolving apparent conflicts between fundamental rights

The subject of this thesis are apparent conflicts between fundamental rights, which represent one of the most important problems contemporary legal systems are faced with. More specifically, this thesis presents and analyses different legal methods that have been suggested as answers to the problem. Contemporary constitutions usually contain provisions protecting certain fundamental rights, such as the right to life, the right to privacy, the right to freedom of expression, personality rights, the right to health, etc. The problem can arise when two (or more) provisions protecting fundamental rights are relevant to the specific situation. The question can then arise: should the behaviour be permitted or prohibited? Judges may then be faced with the situation of having to decide the case without any explicit or clear guidance on how to decide the case. In such situations, lex superior, lex posterior and lex specialis are usually inapplicable, because the provisions regulating fundamental rights are usually on the same hierarchical level, were enacted at the same time and no general – special relationship can be established between them. The problem is further complicated by the fact that the norms expressing fundamental rights are generally understood as legal principles, supposedly different from legal rules. These cases are commonly referred to and known in the literature as hard cases. In order to decide such cases and solve the problem we are faced with various legal methods have been proposed. These methods represent possible answers to the problem of the resolution of the apparent conflicts between fundamental rights. The term “apparent” is used, since there is a debate regarding the existence of “real” conflicts between fundamental rights. The objective of the thesis is to provide an answer to the research question: What are the legal methods of resolving apparent conflicts between fundamental rights and what are their merits in comparison to each other? In order to answer the research question, different legal methods that have been suggested as an answer to the problem of apparent conflicts between fundamental rights are presented, analysed and compared. In this way, the thesis aims to contribute to the understanding of the strengths and weaknesses of the different legal methods that have been proposed to solve the problem. To achieve this, the thesis is divided into three main chapters, each of which presents and analyses different legal methods on apparent conflicts between fundamental rights. In Chapter I and Chapter II, the main legal method proposed to resolve apparent conflicts between fundamental rights – judicial balancing – is presented and analysed. In Chapter III, alternative, non-balancing legal methods for resolving apparent conflicts between fundamental rights are presented and analysed. Chapter I presents and analyses Alexyan theory of judicial balancing, developed by Robert Alexy and further refined by his disciples Jan-Reinard Sieckmann, Martin Borowski and Matthias Klatt. Chapter II presents and analyses approaches from Aharon Barak, Manuel Atienza, José Juan Moreso, Riccardo Guastini and Susan Lynn Hurley. In Chapter III, alternative, non-balancing legal methods for resolving apparent conflicts between fundamental rights are presented and analysed. The authors whose approaches are analysed and presented in this chapter are, in this order: Ronald Dworkin, Luigi Ferrajoli, Juan Antonio García Amado, Lorenzo Zucca and Ruth Chang

Main topics of DAI : a review

A new branch of artificial intelligence, distributed AI, has developed in the last years. Topic is the cooperation of AI-systems which are distributed among different autonomous agents. The thereby occuring problems extend the traditional AI spectrum and are presented along the major DAI-relevant topics: Knowledge representation, task-decomposition and -allocation, interaction and communication, cooperation, coordination and coherence, organizational models, agent\u27s modelling of other agents and conflict resolution strategies (e.g. negotiation). First we try to describe the role of DAI within AI. Then every subsection will take up one special aspect, illuminate the occurring problems and give links to solutions proposed in literature. Interlaced into this structure are sketchy descriptions of a few very prominent and influential DAI systems. In particular we present the Contract Net Protocol, the Distributed Vehicle Monitoring Testbed, the Air Traffic Control problem and the Blackboard Architecture

A Polynomial Time Subsumption Algorithm for Nominal Safe ELO⊥ELO_{\bot} under Rational Closure

Description Logics (DLs) under Rational Closure (RC) is a well-known framework for non-monotonic reasoning in DLs. In this paper, we address the concept subsumption decision problem under RC for nominal safe $ELO_{\bot}$, a notable and practically important DL representative of the OWL 2 profile OWL 2 EL. Our contribution here is to define a polynomial time subsumption procedure for nominal safe $ELO_{\bot}$ under RC that relies entirely on a series of classical, monotonic $EL_{\bot}$ subsumption tests. Therefore, any existing classical monotonic $EL_{\bot}$ reasoner can be used as a black box to implement our method. We then also adapt the method to one of the known extensions of RC for DLs, namely Defeasible Inheritance-based DLs without losing the computational tractability