The E-SHIQ Contextual Logic Framework

Artificial Intelligence: Theories, …, 2010

The Semantic Web aims at augmenting the WWW with meaning, assisting people and machines in comprehending Web content and better satisfying their requests. Intelligent agents are considered to be greatly favored by Semantic Web technologies, because of the interoperability the latter will achieve. One of the main problems in agent interoperation is the great variety in reasoning formalisms, as agents do not necessarily share a common rule or logic formalism. This paper reports on the implementation of EMERALD, a knowledge-based framework for interoperating intelligent agents in the Semantic Web. More specifically, a multi-agent system was developed on top of JADE, featuring trusted, third party reasoning services, a reusable agent prototype for knowledge-customizable agent behavior, as well as a reputation mechanism for ensuring trust in the framework. Finally, a use case scenario is presented that illustrates the viability of the proposed framework.

2010

International Journal of Approximate Reasoning, 1999

In this paper a multi-valued propositional logic — logic of agreement — in terms of its model theory and inference system is presented. This formal system is the natural consequence of a new way to approach concepts as commonsense knowledge, uncertainty and approximate reasoning — the point of view of agreement. Particularly, it is discussed a possible extension of the

Lecture Notes in Computer Science, 1996

We present a logical framework for reasoning about multi-agent systems. This framework uses Giunchiglia et al.'s notion of a logical context to de ne a methodology for the modular speci cation of agents and systems of agents. In particular, the suggested methodology possesses important features from the paradigm of object-oriented (OO) design. We are particularly interested in the speci cation of agent behaviours via BDI theories|i.e., theories of belief, desire and intention. We explore various issues arising from the BDI speci cation of systems of agents and illustrate how our framework can be used to specify bottom-level agent behaviour via the speci cation of top-level intentions, or to reason about complex \emergent behaviour" by specifying the relationship between simple interacting agents.

ArXiv, 2020

In this paper, we extend previous work on distributed reasoning using Contextual Defeasible Logic (CDL), which enables decentralised distributed reasoning based on a distributed knowledge base, such that the knowledge from different knowledge bases may conflict with each other. However, there are many use case scenarios that are not possible to represent in this model. One kind of such scenarios are the ones that require that agents share and reason with relevant knowledge when issuing a query to others. Another kind of scenarios are those in which the bindings among the agents (defined by means of mapping rules) are not static, such as in knowledge-intensive and dynamic environments. This work presents a multi-agent model based on CDL that not only allows agents to reason with their local knowledge bases and mapping rules, but also allows agents to reason about relevant knowledge (focus) -- which are not known by the agents a priori -- in the context of a specific query. We present...

Proceedings of the 2nd International Conference on Web Intelligence, Mining and Semantics - WIMS '12, 2012

This tutorial will discuss about issues, technologies and tools that concern the way that the Semantic Web affects knowledge and information interchange among intelligent agents in multi-agent systems, as well as reasoning interoperability. First, the tutorial will discuss how semantic web rules and ontologies interact with each other in order to be used as the agent's internal knowledge base for environment awareness and decision making. Then, interoperability between reasoning systems for agents will be discussed. The issues involved in all the previous discussion will be exemplified using actual implemented tools for semantic web reasoning in multi-agents systems.

Decision Support Systems, 1994

2008

E-Commerce describes the revolution that is currently transforming the way business is conducted, through the use of information technology, and in particular the World Wide Web. Brokering and negotiation are fundamental stages of e-Commerce. The last few years, there has been an increasing interest for the automation of these two stages. This is partially achieved by the use of software agents. As machines start to engage in business processes, information must be organized in such a way that is accessible by both humans and machines. Additionally, machines must be able to access, process and interpret the information in the same way. Semantic Web vision promises to handle these new issues. Electronic Brokering is a good candidate for taking up Semantic Web technology. We study the brokering or matchmaking problem that is, how a requester's requirements and preferences can be matched against a set of offerings collected by a broker. The proposed solution uses the Semantic Web standard of RDF to represent the offerings, and defeasible logic, which is based on non-monotonic reasoning, for expressing the requirements and preferences. We motivate and explain the approach we propose, and report on a prototypical implementation of a semantic brokering system, exhibiting the described functionality, in JADE multi-agent environment. Expression of negotiation strategies is also of great importance in e-Commerce procedure. We exploit the use of defeasible logic for expressing negotiation strategies. We also implement a negotiating logicbased agent architecture in JADE multi-agent environment. viii 2.1.1 Agent Terminology ___________________________________________ 6 2.1.2 Multi-Agent Systems and Challenges _____________________________ 7 2.1.3 Agent and Service Discovery ____________________________________ 7 2.1.3.1 Centralized Solutions _________________________________7 2.1.3.2 Distributed Solutions__________________________________9 2.1.4 Agent Communication _________________________________________ 9

Lecture Notes in Computer Science, 2010

Description logics [1] refer to a family of formalisms concentrated around concepts, roles and individuals. They are used in many multiagent and semantic web applications as a foundation for specifying knowledge bases and reasoning about them. One of widely applied description logics is SHIQ [7,8]. In the current paper we address the problem of inconsistent knowledge. Inconsistencies may naturally appear in the considered application domains, for example as a result of fusing knowledge from distributed sources. We define three threevalued paraconsistent semantics for SHIQ, reflecting different meanings of concept inclusion of practical importance. We also provide a quite general syntactic condition of safeness guaranteeing satisfiability of a knowledge base w.r.t. threevalued semantics and define a faithful translation of our formalism into a suitable version of a two-valued description logic. Such a translation allows one to use existing tools and SHIQ reasoners to deal with inconsistent knowledge.

Proceedings of the Sixth International Conference, …, 1998

In this paper we present a new semantics, called Local Models Semantics, and use it to provide a foundation to reasoning with contexts. This semantics captures and makes precise the two main intuitions underlying contextual reasoning: (i) reasoning is mainly local and uses only part of what is potentially available (e.g., what is known, the available inference procedures), this part is what we call context (of reasoning); however (ii) there is compatibility among the reasoning performed in different contexts. We validate our semantics by formalizing two important forms of contextual reasoning: reasoning with viewpoints and reasoning about belief. This paper is a substantially revised and extended version of a paper with the same title presented at the 1998 Knowledge Representation and Reasoning conference (KR'98). The order of the names is alphabetical.