* This research is partially supported by the MAIS project financed by MIUR -"Ministero dell'Istruzione, dell'Università e della Ricerca° in the context of the FIRB program "Fondo per gli Investimenti della Ricerca di Base". Abstract

Legacy systems maintenance involves different decisions, often very complex and sometimes requiring high costs and time. Hence studying and applying the right system modernization technique becomes very important for systems evolution. One of the solutions often adopted to modernize a system is the possibility to migrate it towards a SOA architecture. A lot of works in the literature have been done in this direction, which propose methodologies that provide some kind of migration strategy.In the migration process one of the main tasks is related to system comprehension. We often have to analyze not well documented systems, where it is difficult to identify the components which could become services or to recognize the possible problems we could face during the migration process. Software architecture reconstruction is certainly a relevant key activity, which is used for these purposes.In this paper we explore if design pattern detection could be also useful in the migration process: knowing that some design patterns have been applied in the system could give relevant hints to take decisions during migration.

This paper aims to present the main software components we have developed in the context of the ARM (Adaptive Resource Management) project at University of Milano-Bicocca for an adaptive, distributed, service-oriented architecture. The goal of ARM is to manage the resources of a system in a way that enables it to dynamically identify and execute services on the available resources. Our approach chooses the most appropriate resource that is able to execute a service with the requested qualities of service (QoSs). To achieve adaptivity, ARM uses reflection at the architectural level. Exploiting the reflective representation of the system's resources and their related QoSs, ARM may organize them accordingly to various criteria and evaluate them based on their QoSs features and their potentiality in executing a requested service with the requested QoSs. To validate the ARM concepts, a prototype based on the peer-to-peer paradigm is currently under development. It aims to provide an adaptive support when using the resources available in our department.

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.

The decomposition of design patterns into simpler elements may reduce significantly the creation of variants in forward engineering, while it increases the possibility of identifying applied patterns in reverse engineering. Nevertheless, there are few reverse engineering tools that exploit the decomposition of patterns (i.e., FUJABA, SPQR). The SPQR approach introduces a catalog of elemental design patterns (EDP) and a rule set based on sigma-calculus through which EDPs are defined and composed into design patterns. Considering the SPQR approach particularly interesting, we propose a novel solution for defining and detecting EDPs and, further, design patterns. Our approach defines EDPs as logical functions of eight symbolic variables, each variable representing a method call (e.g., method name, method signature, method declaration, this reference, super reference) or a class property (superclass, same family, same object). An EDP detector has been developed based on this approach, representing a starting point for future developments towards design pattern recognition in the reverse engineering context.

In this paper we describe a work in progress at University of Salerno concerning the realization and experimentation of a Distributed Learning Environment Support Tool developed by means of 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 providing first experimental results.We firstly give a general description of our system, utilizing Object-Oriented methodologies together with Event Diagrams showing interactions among 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, starting 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 highflexibility, and scalability features.

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