infonet-economy

We define 'SPEM fragments' of five methods for developing self-organising multi-agent systems. Self-organising traffic lights controllers provide an application scenario.

Current solutions for industrial manufacturing assembly systems do not suit the needs of mass customization industry, which is facing low production volumes, many variants and rapidly changing conditions. This paper proposes the concept of self-organizing evolvable assembly systems, where assembly system modules and product parts to be assembled self-organize and self-adapt (among others, choose their coalition partners, their location and monitor themselves) in order to easily and quickly produce a new or reconfigured assembly system each time a new product order arrives or each time a failure or weakness arises in the current assembly system. This paper presents the design and partial implementation of such a system following an architecture for self-organizing and self-adaptive systems based on policies enforced at run-time on the basis of collected and updated metadata. As a case study, the assembly of a adhesive tape roller dispenser is considered.

Emerging computing infrastructures are heterogeneous, ubiquitous and mobile. Devices from personal computers, to handhelds, to printers, to embedded devices are very widely available. Further, today's wireless network infrastructures make it possible for devices to spontaneously interact. Many devices are mobile, carried by people or mobile machines. Thus, the environment available to a device is constantly changing. This notion also encapsulates issues such as security policy and physical properties such as network signal strength, or printers availability. By their heterogeneity, scale, and dynamism, these systems gain to be designed so that they organise themselves autonomously. Usually interaction among devices that do not know each other occurs through some exchange of information specifying their respective capabilities. However, in a dynamic and unsecure environment, this is not sufficient. On the one hand, a malicious entity can exhibit desirable characteristics, while it is not able to realise them. On the other hand, even if in good faith, a printer can fail because it lacks toner or paper. The approach proposed in this paper is to combine information that entities carry about themselves, with trust or reference information exchanged among entities about other entities. Trust enables adaptation of running entities to the dynamic modifications of their environment. For instance, in the case of users and printers, a printer exhibits its characteristics, such as postscript, double-sided, black and white, and users exchange trust information about printers based on their observations and experiences realised with the printers, such as frequent paper jams, or low toner. Trust circulates among users about printers. Trust in a well functioning printer raises, while trust in an always broken down printer decreases. This paper shows first that the human notion of trust is actually a self-organising mechanism according to Nobel Prize Prigogine criteria for self-organisation. Second, it formally proposes an interaction mechanism based on a tag-based model where entities are equipped with a marking, carrying a specification of the functional as well as non-functional capabilities they offer to the community; and on a trust-based model, where trust information are exchanged among principals. The paper demonstrates as well the approach through a small example involving users and printers. Finally, the paper discusses notions inherent to the human notion of trust, such as belief and confidence in entities expressing trust, as well as the notion of risk which is intimately linked to the notion of trust.

This paper presents the combination of two well established principles: the CO-OPN synchronisation mechanism, and the Merlin and Farber time Petri nets. Real-time synchronised Petri nets systems are then defined such that a Petri net is an object that can ask to be synchronised with another net, and whose transition firing is constrained by relative time intervals. Our proposal enables to define complex systems with compact specifications, whose semantics is given through a small set of Structured Operational Semantics (sos) rules. The applicability of the new model is shown by applying it to a traditional benchmark adopted in the literature of real-time systems

The rapid expansion of Java programs into the software market is often not supported by a proper development methodology. We present a formal development methodology, well suited for Java dependable distributed applications. It is based on the stepwise refinement of model oriented formal specifications, and enables validation of the obtained system wrt the client's requirements. Three refinement steps have been identified in the case of fault tolerant distributed applications: first, starting from informal requirements, an initial formal specification is derived. It does not depend on implementation constraints and provides a centralized solution; second, dependability and distribution constraints are integrated; third, the Java implementation is realised. The CO-OPN/2 language is used to express specifications formally; and the dependability and distribution design as based on the Coordinated Atomic action concept. The methodology and the three refinement steps are presented through a very simple fault tolerant distributed Java application.

The need for flexible protocol stacks in communication software, instead of static, predefined protocol stacks, has been more and more asserted these last years. We present here a new environment, COMSCRIPT, which addresses the implementation of flexible protocol stacks directed by the application. COMSCRIPT is a new programming language, derived from POSTSCRIPT, which follows an interpretative approach to perform protocols. COMSCRIPT is also an interpreter, that lets execute concurrently event driven processes, whose communications occur, either synchronously or quasi-asynchronously, through synchronization points linked to gates. This paper explains these concepts and shows that the COMSCRIPT language is suited for the implementation of communication protocol entities. It also shows how the COMSCRIPT environment uses these concepts to achieve dynamic protocol stack configuration.

The DVP project investigated the Quality of Service (QoS) requirements of broadcasters for several forms of distributed video production and run a series of trials of distributed virtual studios (studio on demand), distributed virtual reality, distributed musical rehearsals and distributed video editing and retrieval. The CUI of the University of Geneva participated in the DVP project in the distributed musical rehearsal (DR) and distributed video editing and retrieval (DVER) applications.

Les monographies scientifiques présentent des caractéristiques propres en ce qui concerne le contenu et le mode de production lié à la démarche scientifique. Le but de cette étude est de définir un modèle pour la représentation et le travail sur des monographies qui évoluent au cours du temps et que l'on désire aborder selon différents points de vues. Le modèle que nous proposons comprend un modèle de représentation des fragments d'informations qui constituent la monographie et de leur relations; un modèle spécifique pour la représentation des concepts (fragments terminologiques) et un modèle pour la création de vues hypertextuelles adaptées aux différents objectifs des utilisateurs (auteurs, éditeurs, lecteurs). Les définitions de concepts, qui jouent un rôle primordial dans les textes scientifiques, sont représentées dans un langage formel, de type logique descriptive, qui permet de leur appliquer divers traitements automatiques. De plus, un même concept peut être défini selon divers points de vue. Un langage purement déclaratif permet la définition des vues qui constituent l'interface de la monographie. Nous présentons également l'architecture d'un système de gestion de monographies utilisant la technologie des bases de données et un système de génération de vues hypertextes pour les bases de données.

When performing document search, scientists have specific goals in mind. We conducted interviews with scientists to understand exactly how they were looking for information and working with documents. We found that scientists are generally searching specific discourse elements, not the en- tire document. Therefore, we created an annotation model that can represent the different types of discourse elements contained in documents. We have implemented this model in the form of an OWL ontology and a semantic indexing and retrieval tool. The experiments we have conducted (in the gender studies field) show that the model is sufficient to represent a large part of the document contents and that it is possible to automatically annote documents according to this model. We also showed that this model can be used to answer specific and complex queries on a corpus of scientific documents.

A hypertext view is a derived hypertext for a given database. We are interested in providing a mechanism of translating hypertext view update operations to appropriate data manipulation operations in database. However, given a hypertext view update operation, we cannot always uniquely determine what needs to be done in terms of database operations to perform the intended hypertext view update operation. Therefore, the goal of this study is to identify ambiguities that arise in the translation mechanism and investigate how link information (i.e., static link information such as links in hypertext and dynamic information such as traversals) can be used in resolving the ambiguities. We provide update semantics for each of the hypertext view update operations and show how the ambiguities can be resolved with link information.