Supporting service discovery, querying and interaction in ubiquitous computing environments.

In this paper, we contend that ubiquitous computing environments will be highly heterogeneous, service rich domains. Moreover, future applications will consequently be required to interact with multiple, specialised service location and interaction protocols simultaneously. We argue that existing service discovery techniques do not provide sufficient support to address the challenges of building applications targeted to these emerging environments. This paper makes a number of contributions. Firstly, using a set of short ubiquitous computing scenarios we identify several key limitations of existing service discovery approaches that reduce their ability to support ubiquitous computing applications. Secondly, we present a detailed analysis of requirements for providing effective support in this domain. Thirdly, we provide the design of a simple extensible meta-service discovery architecture that uses database techniques to unify service discovery protocols and addresses several of our key requirements. Lastly, we examine the lessons learnt through the development of a prototype implementation of our architecture

The many faces of publish/subscribe

Well adapted to the loosely coupled nature of distributed interaction in large-scale applications, the publish/subscribe communication paradigm has recently received increasing attention. With systems based on the publish/subscribe interaction scheme, subscribers register their interest in an event, or a pattern of events, and are subsequently asynchronously notified of events generated by publishers. Many variants of the paradigm have recently been proposed, each variant being specifically adapted to some given application or network model. This paper factors out the common denominator underlying these variants: full decoupling of the communicating entities in time, space, and synchronization. We use these three decoupling dimensions to better identify commonalities and divergences with traditional interaction paradigms. The many variations on the theme of publish/subscribe are classified and synthesized. In particular, their respective benefits and shortcomings are discussed both in terms of interfaces and implementations

A Taxonomy of Self-configuring Service Discovery Systems

We analyze the fundamental concepts and issues in service discovery. This analysis places service discovery in the context of distributed systems by describing service discovery as a third generation naming system. We also describe the essential architectures and the functionalities in service discovery. We then proceed to show how service discovery fits into a system, by characterizing operational aspects. Subsequently, we describe how existing state of the art performs service discovery, in relation to the operational aspects and functionalities, and identify areas for improvement

Analysis and conception of tuple spaces in the eye of scalability

Applications in the emerging fields of eCommerce and Ubiquitous Computing are composed of heterogenous systems that have been designed separately. Hence, these systems loosely coupled and require a coordination mechanism that is able to gap spatial and temporal remoteness. The use of tuple spaces for data-driven coordination of these systems has been proposed in the past. In addition, applications of eCommerce and Ubiquitous Computing are not bound to a predefined size, so that the underlying coordination mechanism has to be highly scalable. However, it seems to be difficult to conceive a scalable tuple space. This report is an English version of the author\u27s diploma thesis. It comprises the chapter two, three, four, and five. By this means, the design and the implementation of the proposed tuple space is not part of this report

Providing location transparent services with Java technologies : testing support of Open Distributed Processing transport transparencies in JINI, web services and JXTA

Masteroppgave i informasjons- og kommunikasjonsteknologi 2002 - Høgskolen i Agder, GrimstadThis thesis tests the presence of Open Distributed Processing (ODP) distribution transparencies in Jini, Jxta and Web Services. The thesis presents an introduction to each technology, a description of the test criteria developed, selection of prototype applications, test execution and presentation of the results. Main focus is on testing support of transparencies at the application developer and system designer level. The work has shown that all technologies support transparence types that have to do with the location of a service; location transparency and migration transparency. But when it comes to replication transparency, this is not supported by Web Services. Jini provides functions to achieve failure transparency in the JavaSpace extension; neither Web Services nor Jxta provides this

Constraint-Based Personalization For Business Applications

This paper reports on extensions of previous work applying personalization techniques and constraint-based methods within an intelligent agent framework.  The Wise Net Inc. has developed an intelligent agent framework specifically for providing advanced scalable collaborative capabilities for easy integration with existing web-enabled enterprise applications.  Since the summer of 2001, the author, his colleagues, and his research assistants, have been conducting applied research aimed at discovering the desired personalization models and effects to support collaborative e-business systems.  Intelligent agents are being developed to implement these personalization effects through constraint-satisfaction methods and solvers.  This paper documents the approach, progress achieved to date, and future directions.  This work is being supported by The Wise Net Inc., the BC Advanced Systems Institute (BC ASI), and the Canadian National Research Council (NRC) through the Industrial Research Assistance Program (IRAP)

Service-oriented Distributed Applications in the Future Internet: The Case for Interaction Paradigm Interoperability

International audienceThe essential issue of interoperability in distributed systems is becoming even more pressing in the Future Internet, where complex applications will be composed from extremely heterogeneous systems. Open system integration paradigms, such as service oriented architecture (SOA) and enterprise service bus (ESB), have provided answers to the interoperability requirement. However, when it comes to integrating systems featuring heterogeneous interaction paradigms, such as client-service, publish-subscribe and tuple space, existing solutions are typically ad hoc and partial, applying to specific interaction protocol technologies. In this paper, we introduce an interoperability solution based on abstraction and merging of the common high-level semantics of interaction paradigms, which is sufficiently general and extensible to accommodate many different protocol technologies. We apply this solution to revisit the SOA- and ESB-based integration of heterogeneous distributed systems