Abstract. Publish/subscribe is considered one of the most important interaction styles for the explosive market of enterprise application integration. Producers publish information on a software bus and consumers subscribe to the information they want to receive from that bus. The decoupling nature of the interaction between the publishers and the subscribers is not only important for enterprise computing products but also for many emerging e-commerce and telecommunication applications. It is often claimed that object-orientation is inherently incompatible with the publish/subscribe interaction style. This flawed argument is due to the persistent confusion between object-orientation as a modeling discipline and the specific request/reply mechanism promoted by CORBA-like middleware systems. This paper describes object-oriented abstractions for publish/subscribe interaction in the form of Distributed Asynchronous Collections (DACs). DACs are general enough to capture the commonalities of various publish/subscribe interaction styles, and flexible enough to allow the exploitation of the differences between these flavors.

Multi Agent Systems (MAS) are often used as a software substrate in creating smart spaces. Many of the solutions already developed within the MAS community are applicable in the domain of smart spaces. Others, however, need to be modified or re-developed. In particular, it has to be noted that many agents acting in a physical space domain are restricted in number and capability by the scarce physical hardware available. Those limitations need to be taken into account when coordinating agent activities in a MAS in a smart space. In this paper we present Rascal, a high-level resource management system for the Intelligent Room Project, that addresses physical resource scarcities. Rascal performs the service mapping and arbitration functions for the system. Rascal is an implemented tool and has been partially deployed for day-to-day use. 1

We believe that it is interes) tos)2 thes ys)2 ands) ware architecture of environments which integrate the evolving ideas of computational grids dis)- objects webs ervices peer-topeer networks and mes oriented middleware. Such peer-to-peer(P2P)Grids s houlds eamles integrate us tothems2 es and to res) which areals linked to each other. We canabs ss h environments as adis)- ss of "clients which cons2 either of"us or "res2)- or proxies thereto.Thes clients mus be linked together in a flexible fault tolerant e#cient high performancefasmanc Inthis paper, wes2 the mes) or events - termed GES or the Grid Event Service -- thatis appropriate to link the clients (bothus andres2) of cours together. For our purp osp (regis)- trans orting and dis vering information), events arejusmes - typically with timesme)22 Themes2) ss GES mus s cale over a wide variety ofdevices - from hand heldcomputers at one end to high performancecomputers ands) at the other extreme. We have analyzed the requirements of s) eral Grids ervices that could be built with this model, including computing and education and incorporatedconsd) ts of collaboration with as hared event model. Wes2 that generalizing the well-knownpublis-)s e modelis an attractive approach and here wes2 s2 of theis to be addres)- if this modelis us in the GES. 1 Introducti The web in recent years has experienced an explosion in tj number of devices users employt o access services. A single user may access acert"E service using multEQE devices. Most services allow client st o accesst he servicet hrough a broker. The client istjF forcedt intjE"G wit tt service viat his broker tGF--GFjOF tG duratFj tra it is usingt he service. If tj broker fails,t he client is denied servicingtrv suchtQ" t" failed broker recovers. Int he event t hat t his...

Technological advances in semiconductor processing and design as well as wireless networking are leading us towards the vision of Pervasive Computing. We envision that in the (near) future, devices all around a person, either embedded as a part of smart spaces, or being carried by other people in the vicinity, will provide an array of services that she might want to use. Development of customized services by integrating and executing existing ones has received a lot of attention in the last few years with respect to wired, infrastrutcure based web-services. However, service discovery and composition in web-based environments is performed in a centralized manner with the help of a fixed entity. Moreover, wired infrastructure-based service discovery and composition architectures do not take into consideration factors arising from the possible mobility of the service providers. In this paper, we present a distributed, de-centralized and fault-tolerant design architecture for reactive service composition in pervasive environments. The design of the architecture is based on a peer-to-peer model. We introduce two reactive techniques for service composition in our design. We also present the Anamika system, an initial implementation of our design architecture. We present experiments to show the functioning of our design and implementation.

Abstract. The European Commission’s eEurope initiative aims to bring every citizen, home, school, business and administration online to create a digitally literate Europe. The value lies not in the objective itself, but in its ability to facilitate the advance of Europe into new ways of living and working. Just as in the first literacy revolution, our lives will change in ways never imagined. The vision of eEurope is underpinned by a technological infrastructure that is now taken for granted. Yet it provides us with the ability to pioneer radical new ways of doing business, of undertaking science, and, of managing our everyday activities. Key to this step change is the development of appropriate mechanisms to automate and improve existing tasks, to anticipate desired actions on our behalf (as human users) and to undertake them, while at the same time enabling us to stay involved and retain as much control as required. For many, these mechanisms are now being realised by agent technologies, which are already providing dramatic and sustained benefits in several business and industry domains, including B2B exchanges, supply chain management, car manufacturing, and so on. While there are many real successes of agent technologies to report, there is still much to be done in research and development for the full benefits to be achieved. This is especially true in the context of environments of pervasive computing devices that are envisaged in coming years. This paper describes the current state-of-the-art of agent technologies and

To operate in dynamic and potentially unknown scenarios a mobile client discovers the local services that match its requirements, and interacts with these to obtain the application functionality. However, mobile environments are populated by heterogeneous mobile service platforms; these range from discovery protocols including SLP, UPnP and Jini to different styles of service interaction paradigms e.g. Remote Procedure Call, Publish-Subscribe and agent based solutions. Therefore given this type of heterogeneity, utilizing single discovery and interaction systems is not optimal as the client will only be able to use the services available to that particular platform. Hence, in this paper we present an adaptive middleware solution to this problem. ReMMoC is a Web-Services based reflective middleware that allows mobile clients to be developed independently of both discovery and interaction mechanisms. We describe the architecture, which dynamically reconfigures to match the current service environment. Finally, we investigate the incurred performance overhead such dynamic behaviour brings to the discovery and interaction process. I.

The emergence of mobile devices and wireless networks has created a new path in the field of e-commerce: "mcommerce ". Significant research is needed, in the field of service discovery, to support m-commerce applications. Various new applications, that would use services available to a mobile device from both the fixed network backbone and peer mobile devices in its proximity, are being developed. M-commerce applications have the challenging task of discovering services in a dynamically changing environment. The DARPA Agent Markup Language (DAML) is an important tool in the process of developing the Semantic Web. In this paper, we present a dynamic service discovery infrastructure that uses DAML to describe services and a Prolog reasoning engine to perform matching using the semantic content of service descriptions. We believe that the architecture we have designed is a necessary component of any m-commerce infrastructure.

Recent advances in wireless networking technologies and the growing success of mobile computing devices, such as laptop computers, third generation mobile phones, personal digital assistants, watches and the like, are enabling new classes of applications that present challenging problems to designers. Mobile devices face temporary loss of network connectivity when they move; they are likely to have scarce resources, such as low battery power, slow CPU speed and little memory; they are required to react to frequent and unannounced changes in the environment, such as high variability of network bandwidth, and in the resources availability. To support designers building mobile applications, research in the field of middleware systems has proliferated. Middleware aims at facilitating communication and coordination of distributed components, concealing complexity raised by mobility from application engineers as much as possible. In this survey, we examine characteristics of mobile distributed systems and distinguish them from their fixed counterpart.

Pervasive computing, with its focus on users and their tasks rather than on computing devices and technology, provides an attractive vision for the future of computing. But, while hardware and networking infrastructure to realize this vision are becoming a reality, precious few applications run in this infrastructure. We believe that this lack of applications stems largely from the fact that it is currently too hard to design, build, and deploy applications in the pervasive computing space.

Vinci is a local area service-oriented architecture designed for rapid development and management of robust web applications. Based on XML document exchange, Vinci is designed to complement and interoperate with wide area service-oriented architectures such as E-Speak and .NET. This paper presents the Vinci architecture, the rationale behind its design, and an evaluation of its performance. Specifically, we show how systems architected with Vinci are developed quickly, scaled effortlessly, and easily moved from prototype to production.