Abstract not found

Automated negotiation is a key form of interaction in systems that are composed of multiple autonomous agents. The aim of such interactions is to reach agreements through an iterative process of making offers. The content of such proposals are, however, a function of the strategy of the agents. Here we present a strategy called the trade-off strategy where multiple negotiation decision variables are traded-off against one another (e.g., paying a higher price in order to obtain an earlier delivery date or waiting longer in order to obtain a higher quality service). Such a strategy is commonly known to increase the social welfare of agents. Yet, to date, most computational work in this area has ignored the issue of trade-offs, instead aiming to increase social welfare through mechanism design. The aim of this paper is to develop a heuristic computational model of the trade-off strategy and show that it can lead to an increased social welfare of the system. A novel linear algorithm is presented that enables software agents to make trade-offs for multi-dimensional goods for the problem of distributed resource allocation.

While decision theory provides an appealing normative framework for representing rich preference structures, eliciting utility or value functions typically incurs a large cost. For many applications involving interactive systems this overhead precludes the use of formal decision-theoretic models of preference. Instead of performing elicitation in a vacuum, it would be useful if we could augment directly elicited preferences with some appropriate default information. In this paper we propose a case-based approach to alleviating the preference elicitation bottleneck. Assuming the existence of a population of users from whom we have elicited complete or incomplete preference structures, we propose eliciting the preferences of a new user interactively and incrementally, using the closest existing preference structures as potential defaults. Since a notion of closeness demands a measure of distance among preference structures, this paper takes the first step of studying various distance mea...

We propose a classification of measures enabling to compare fuzzy characterizations of objects, according to their properties and the purpose of their utilization. We establish

We present an approach to determine the similarity of classes which utilizes fuzzy and incomplete terminological knowledge together with schema knowledge. We clearly distinguish between semantic similarity determining the degree of resemblance according to real world semantics, and structural correspondence explaining how classes can actually be interrelated. To compute the semantic similarity we introduce the notion of semantic relevance and apply fuzzy set theory to reason about both terminological knowledge and schema knowledge. 1 Introduction The identification of similar or corresponding concepts forms one of the main steps when investigating different world models and relating them to each other. Apart from its long tradition in document retrieval, this issue has also been investigated in more structured frameworks such as schema independent query formulation, e.g., [Mot90], or database integration, where for a survey you may look at [SL90]. As argued in [GPN91], there should b...

This chapter presents a review of various interpretations of the fuzzy membership function together with ways of obtaining a membership function. We emphasize that different interpretations of the membership function call for different elicitation methods. We try to make this distinction clear using techniques from measurement theory.

In this paper, we present a Fuzzy Relational Databases model whose main characteristics are: the integration of previous models in the same framework, representation capabilities for a wide series of fuzzy information and a coherent and flexible handling of it. This model aims to solve each problem of representation and handling of fuzzy information taking into account its specific nature, and hence it allows the user to choose the comparison operator and the fuzzy compatibility measure to be used in a query. Besides, it permits the user to specify the precision with which the conditions involved in a query are satisfied. Keywords: Fuzzy Relational Database, Database, Fuzzy Sets, Relational Model 1 Introduction The aim of this paper is to present a fuzzy extension to the Databases Relational Model. This extension will try to solve the problems related to the representation and handling of imprecise information. Because of this, we will have to incorporate some new elements into the Rel...

This paper presents an approach to object oriented requirements engineering and business process re-engineering with a number of advantages over the widely used use case technique. It points out some problems with the use case approach and explains the origins of the idea of task scripts. It compares the two approaches and defines their interrelatedness. The paper sets out to improve and clarify the terminology in use with respect to concepts such as use cases, scenarios and scripts and, in doing so, offers a generification of the use case concept: the task script. This clarification may be viewed as an object oriented ‘analysis pattern’: the syllogism pattern. The concepts are introduced in the context of SOMA: a practical approach to business process modelling based on the object oriented metaphor of message passing. In this approach, messages represent semiotic acts that are expressions of contractual relationships between stakeholders in a business process and the artefacts used by them. It is also indicated how the business process model can be converted into a potentially implementable business object model and the two models linked seamlessly together. Finally, task scripts are compared with Constantine’s ‘essential use cases’.

In this paper we propose a natural approach to handle imprecise numbers as they arise for example from measurements. Fuzzy sets turn out to be a canonical representation for such imprecise numbers that are induced by taking different tolerance or error bounds into account. Fuzzy sets are induced by scaling factors that describe the magnitude of the imprecision. On the other, the scaling factors can be derived from given fuzzy sets so that we have a correspondence between scaling factors and fuzzy sets. When these concepts are applied to control problems, the max--min rule is rediscovered as an interpolations technique. Viewing fuzzy control as an interpolation technique in vague environments enables us to validate various concepts for the design and tuning of fuzzy controllers and suggests new also new methods based on clear semantics. Keywords: Vague environment; interpolation; fuzzy control. 1 Introduction The formal definition of a fuzzy set as a mapping from an underlying univers...

Fuzzy set theory is based on a `fuzzification' of the predicate 2 (element of), the concept of membership degrees is considered as fundamental. In this paper we elucidate the connection between indistinguishability modelled by fuzzy equivalence relations and fuzzy sets. We show that the indistinguishability inherent in fuzzy sets can be computed and that this indistinguishability cannot be overcome in approximate reasoning. For our investigations we generalize from the unit interval as the basis for fuzzy sets to the framework of GL--monoids that can be understood as a generalization of MV--algebras. Residuation is a basic concept in GL--monoids and many proofs can be formulated in a simple and clear way using residuation instead of concentrating on special properties of the unit interval. 1 Introduction Fuzzy set theory is based on the idea that many non--mathematical properties cannot be described in terms of crisp sets comprising those elements that fulfill a given property. The...