F. Arcelli

Likelog: a logic programming language for flexible data retrieval

Starting from unification based on similarity, a logic programming system, called Likelog, (LIKEness in LOGic) is derived, thorougly relying on similarity. An operational semantics and a fix-point semantics are defined, using an extension principle for fuzzy operators. The two approaches are proved to be related and a fuzzy extension of the Ieast Herbrand model is given. One of the principal feature of such a logic programming system is to allow flexible information retrieval in deductive data bases.

Constraint-based protocols for distributed problem solving

Abstract Distributed Problem Solving (DPS) approaches decompose problems into subproblems to be solved by interacting, cooperative software agents. Thus, DPS is suitable for solving problems characterized by many interdependencies among subproblems in the context of parallel and distributed architectures. Concurrent Constraint Programming (CCP) provides a powerful execution framework for DPS where constraints define local problem solving and the exchange of information among agents declaratively. To optimize DPS, the protocol for constraint communication must be tuned to the specific kind of DPS problem and the characteristics of the underlying system architecture. In this paper, we provide a formal framework for modeling different problems and we show how the framework applies to simple yet generalizable examples.

An agent based Internet infrastructure for learning commerce

Among the incredible amount of applications brought on the wave by the diffusion of the Internet, the possibility of an electronic commercialization of learning assumes a relevant role. Thousands of people potentially acting as learning material sellers, buyers and brokers are present on the Net asking for an efficient and effective infrastructure allowing them to play their role in this new market. Motivations are present and mature to investigate how to build such an infrastructure. We exploit agents and their mobility feature to develop a system for the electronic commerce of learning materials available on the Web. We tackle the aspects related to the negotiation, sometimes needed, to conclude a transaction and the aspects related to the best ways to save and classify the materials, through the learning object metadata approach and the related standardization efforts. A prototype architecture and its implementation is presented and discussed and directions for future studies are set.Among the incredible amount of applications brought on the wave by the diffusion of the Internet, the possibility of an electronic commercialization of learning assumes a relevant role. Thousands of people potentially acting as learning material sellers, buyers and brokers are present on the Net asking for an efficient and effective infrastructure allowing them to play their role in this new market. Motivations are present and mature to investigate how to build such an infrastructure. We exploit agents and their mobility feature to develop a system for the electronic commerce of learning materials available on the Web. We tackle the aspects related to the negotiation, sometimes needed, to conclude a transaction and the aspects related to the best ways to save and classify the materials, through the learning object metadata approach and the related standardization efforts. A prototype architecture and its implementation is presented and discussed and directions for future studies are set.

Client-server architectures for distributed learning environments: a proposal

Describes work in progress at University of Salerno concerning the realization and experimentation of a distributed learning environment support tool developed by means of the Java language in an intranet environment. In particular, we focus our discussion on the definition of the existing scenario, on the requirements specification and on the description of our overall system, providing initial experimental results. We first give a general description of our system, utilizing object-oriented methodologies together with event diagrams showing interactions among the defined entities. Secondly, we describe a subset of the architecture at a more detailed level and discuss the use of Java and our experiences in interfacing Java-based software architectures with real-world objects in a learning environment. Finally, starring from an initial but reasonably wide experimentation of our system, we introduce an engineering-fashioned discussion showing the evolution from a basic and simple architecture to a more sophisticated one, which has the aim of exhibiting high flexibility, and scalability features.

Distributed Agents for Problem Solving

Abstract Agent-based computing represents a new and very significant paradigm for building a wide range of software applications. In this paper, we describe our research project on the development of a software agent-based architecture for Distributed Problem Solving (DPS). Such agents must be heterogeneous and adaptive in nature to satisfy increasing requests due to cooperation capabilities exhibited by DPS applications (e.g., computer vision applications such as biomedical imaging and image retrieval on the Web, distributed and intelligent information retrieval, and so on). We give a brief introduction to the overall architecture design and focus our attention on the lowest level agents, called W-bots (Working Software Robots). We define the nature of such agents and describe their ways of interaction and their adaptive capabilities.

Software agents for computer vision: a preliminary discussion

We start a preliminary discussion about the development of software agents developed for computer vision. Such agents must be heterogeneous and adaptive in nature to satisfy increasing requests for integration-cooperation capability exhibited by current computer vision applications (e.g. biomedical imaging and image retrieval on the Web). We give a brief introduction to the overall architecture design and we focus on lowest level agents, called W-bots (Working Software Robots). We define the nature of such agents and describe their ways of interaction, and their adaptive capabilities. Finally, we present an example of the proposed architecture utilizing VDM++ to specify agents as active objects.

Multimedia Distributed Learning Environments: Evolution towards Intelligent Communications

In this paper we describe the realization of a Multimedia Distributed Learning System developed by means of the Java language in a Intranet environment. In particular, we focus our discussion on the definition of the existing scenario, on the requirements specification and on the description of our overall system, by providing also first experimental results. We decided to add to our system a Software Agents based Intelligent Communication Support to manage both high level and low level communication needs coming from the nature of the application. Such communication needs could reasonably be considered as shared by a large family of distributed applications based on Intranet technologies. We present the main characteristics of our agents and describe how to use them to better achieve defined goals in terms of flexibility and scalability and to add network-awareness capabilities to the application.In this paper we describe the realization of a Multimedia Distributed Learning System developed by means of the Java language in a Intranet environment. In particular, we focus our discussion on the definition of the existing scenario, on the requirements specification and on the description of our overall system, by providing also first experimental results.We decided to add to our system a Software Agents based Intelligent Communication Support to manage both high level and low level communication needs coming from the nature of the application. Such communication needs could reasonably be considered as shared by a large family of distributed applications based on Intranet technologies. We present the main characteristics of our agents and describe how to use them to better achieve defined goals in terms of flexibility and scalability and to add network-awareness capabilities to the application.

A novel software architecture for computer-aided analysis of circuits with uncertain parameters

In recent years interest has grown in the possibility of applying novel software technologies (such as those from artificial intelligence) to the field of scientific calculus. There is an increasing need of such approaches due to the requests for integration-cooperation features in modern applications, whose simulation tasks are asked to go far beyond the rigid application of presumed general purpose numerical methods. In this paper we explore the use of software agents for circuit-CAD (CCAD) with uncertainty handling capabilities. In such a field, solving some hard problems like tolerance and sensitivity analysis (TSA) for strongly nonlinear circuits in presence of large parameter uncertainties, benefits much more from a clever preliminary choice of the best problem-tuned numerical method rather than from a blind number crunching approach. Software agents seem to meet these constraints while introducing a high degree of flexibility, which enables the implementation of dynamic adaptive resolution schemes for given CCAD tasks. We present an example of use of the proposed architecture utilizing Java to specify agents as active objects. Some applications of the new strategy to TSA circuit-related problems are presented.

Computer Vision Applications Experience with Actors

The paper reports some initial experience in the use of the Actor Model for solving a complex Computer Vision problem: the segmentation of cursive script characters. Our goal is to show how an application programmer can express the different kinds of parallelism present in the problem, emphasizing the advantages obtained by the use of the Actor Model, both from the concurrency and the object-oriented design points of view.