Rachid Saadi, Jean‐Marc Pierson and Lionel Brunie
The challenge of pervasive computing consists in offering access to computing services anywhere and anytime with any devices. However, before it becomes a reality, the problems of…
Abstract
The challenge of pervasive computing consists in offering access to computing services anywhere and anytime with any devices. However, before it becomes a reality, the problems of access control and authentication have to be solved, among others. Existing solutions are inadequate without adaptation to this specific environment. Among the promising approaches, the trust paradigm seems to be more flexible than others. We base this proposal on this paradigm to implement a distrust model, so‐called APC (Access Pass Certificate). The main objective of this model is to enable authorized user to roam and to access trusted sites though they are not known locally. A user can claim two kinds of APCs provided by two kinds of sites: the home site (where the user has an account) and the trusted site (that trusts the user). Using these certificates, the user can progressively extend her access scope. This model implements a decentralized mapping policy, where the correspondence between the user’s home profile and her rights in the trusted sites is determined by the trusted site. This distrust model and its implementation are presented in this article where we exhibit its importance for large but controlled access in pervasive environments.
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Antônio Tadeu A. Gomes, Artur Ziviani, Bruno F. Bastos and Luciana S. Lima
Although wireless grids have been originally thought of as isolated processing clusters, the possibility of their approaching – and connecting to – a fixed network allows for a…
Abstract
Purpose
Although wireless grids have been originally thought of as isolated processing clusters, the possibility of their approaching – and connecting to – a fixed network allows for a huge expansion of their processing power, due to the resources available in wired grids potentially accessible through such a network. The interoperation of mobile ad hoc grids and resources available in wired grids is, however, a problem still to be tackled in the literature. The purpose of this paper is to tackle this problem.
Design/methodology/approach
A prototype is developed to demonstrate the feasibility of the interoperation between wireless and wired grids, thus providing a basis for the development of novel applications that can build on this interoperation.
Findings
The outcome of the paper comprises the analysis of the necessary requirements for the interoperation between wireless and wired grids, the proposal of two different interoperation approaches, and the provision of a qualitative assessment of the implications of these approaches.
Research limitations/implications
There are many points that the authors intend to address as future work. First, they are aware of the need for performing some quantitative analyses of their proxy implementations. Second, they intend to investigate the possibility of mobile ad hoc grids to process tasks coming from wired grids. Third, they are interested in allowing the submission of tasks that present interdependencies (workflows) from mobile devices in the mobile ad hoc grid.
Practical implications
The paper investigates the interoperation of wireless and wired grids. Such an interoperation may open new perspectives of practical use of wireless devices in scenarios such as emergency response networks and field research systems, to name a few.
Originality/value
The paper provides a first step into the interoperation of wireless and wired grids, thus yielding a basis for the development of novel applications that can build upon this interoperation. This is believed to be of interest to both the grid and mobile computing communities.
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The purpose of this paper is to present a component framework for building visual interfaces for pervasive computing systems.
Abstract
Purpose
The purpose of this paper is to present a component framework for building visual interfaces for pervasive computing systems.
Design/methodology/approach
The proposed framework enables end‐users to build visual interfaces for their systems by using document‐editing manner.
Findings
The building and operating visual interfaces are useful for managing pervasive computing systems.
Research limitations/implications
The framework is designed based on Java but programming language‐independent version is needed.
Practical implications
A component framework was implemented for building visual interfaces for pervasive computing.
Originality/value
A framework for visual interfaces for pervasive computing is unique.
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Rabab Hayek, Guillaume Raschia, Patrick Valduriez and Noureddine Mouaddib
The goal of this paper is to contribute to the development of both data localization and description techniques in P2P systems.
Abstract
Purpose
The goal of this paper is to contribute to the development of both data localization and description techniques in P2P systems.
Design/methodology/approach
The approach consists of introducing a novel indexing technique that relies on linguistic data summarization into the context of P2P systems.
Findings
The cost model of the approach, as well as the simulation results have shown that the approach allows the efficient maintenance of data summaries, without incurring high traffic overhead. In addition, the cost of query routing is significantly reduced in the context of summaries.
Research limitations/implications
The paper has considered a summary service defined on the APPA's architecture. Future works have to study the extension of this work in order to be generally applicable to any P2P data management system.
Practical implications
This paper has mainly studied the quantitative gain that could be obtained in query processing from exploiting data summaries. Future works aim to implement this technique on real data (not synthetic) in order to study the qualitative gain that can be obtained from approximately answering a query.
Originality/value
The novelty of the approach shown in the paper relies on the double exploitation of the summaries in P2P systems: data summaries allow for a semantic‐based query routing, and also for an approximate query answering, using their intentional descriptions.
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Luiz Angelo Steffenel, Maxime Martinasso and Denis Trystram
The purpose of this paper is to explain one of the most important collective communication patterns used in scientific applications which is the complete exchange, also called…
Abstract
Purpose
The purpose of this paper is to explain one of the most important collective communication patterns used in scientific applications which is the complete exchange, also called All‐to‐All. Although efficient algorithms have been studied for specific networks, general solutions like those available in well‐known MPI distributions (e.g. the MPI_Alltoall operation) are strongly influenced by the congestion of network resources.
Design/methodology/approach
In this paper we present an integrated approach to model the performance of the All‐to‐All collective operation, which consists in identifying a contention signature that characterizes a given network environment, using it to augment a contention‐free communication model.
Findings
This approach, assessed by experimental results, allows an accurate prediction of the performance of the All‐to‐All operation over different network architectures with a small overhead.
Practical implications
The paper discusses the problem of network contention in a grid environment, studying some strategies to minimize the impact of contention on the performance of an All‐to‐All operation.
Originality/value
The approach used, assessed by experimental results, allows an accurate prediction of the performance of the All‐to‐All operation over different network architectures with a small overhead. Also discussed is the problem of network contention in a grid environment and some strategies to minimize the impact of contention on the performance of an All‐to‐All operation.
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Ren‐Song Ko, Chih‐Chung Lai, Chia‐Kuan Yen and Matt W. Mutka
The problems with poor performance and quality of ubiquitous applications due to limited computing resources are addressed.
Abstract
Purpose
The problems with poor performance and quality of ubiquitous applications due to limited computing resources are addressed.
Design/methodology/approach
The concept of ad hoc systems is introduced based on the idea that a resource‐limited device may cooperate with computers around to complete a complex task. Subsequently, the adaptive software framework, FRAME, may be improved to realize ad hoc systems.
Findings
It is possible to apply the adaptive software framework to the challenges of ad hoc systems, including a lot of user intervention and unstable computing environments.
Research limitations/implications
The present study provides a starting‐point for further research in exploring and utilizing ubiquitous resources to achieve a better user experience.
Practical implications
The component‐based architecture provides a flexible development approach of ubiquitous applications from the software engineering perspective.
Originality/value
Our analysis and experimental results show that the concept of ad hoc systems is practical and can be realized by the adaptive software framework.
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D. Villa, F.J. Villanueva, F. Moya, F. Rincón, J. Barba and J.C. López
The purpose of this paper is to present a new service discovery protocol (SDP) suitable for wireless sensor networks (WSN). The constraints imposed by ultra low‐cost sensor and…
Abstract
Purpose
The purpose of this paper is to present a new service discovery protocol (SDP) suitable for wireless sensor networks (WSN). The constraints imposed by ultra low‐cost sensor and actuators devices (basic components of a WSN) are taken into account to minimize the overall footprint.
Design/methodology/approach
It is based on the lightweight WSN communication model used by picoObjects, a tiny implementation of the distributed object concept and the same design criteria are followed, aiming at minimal overhead for devices and communication protocols. In spite of its simplicity it is powerful enough to deploy a valuable set of services.
Findings
This approach provides a remote interface that client applications can use without knowing where the service is implemented (platform and location independence).
Research limitations/implications
The future work is mainly focused on integrating third party services using different SDPs, making possible the real deployment of large heterogeneous pervasive environments.
Practical implications
Designers may change the underlying SDP model (e.g. centralized versus distributed) without affecting applications by just tweaking configuration settings.
Originality/value
Embedded devices can participate in the service discovering procedure providing their own services by means of standard distributed objects. Also, the protocol is suitable for any kind of dynamic networked system.
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Ningning Cheng, Shaxun Chen, Xianping Tao, Jian Lu and Guihai Chen
Context correctness and fault handling are very important to the quality of service in context‐aware applications. However, they are often ignored by researchers and application…
Abstract
Purpose
Context correctness and fault handling are very important to the quality of service in context‐aware applications. However, they are often ignored by researchers and application developers. This paper aims to present a model for context‐aware applications.
Design/methodology/approach
This paper proposes a transaction model for context‐aware applications, in order to provide a uniform infrastructure for service quality management.
Findings
The paper finds that, in this model, context‐aware applications are organized as a number of logic units and each unit may have a compensation module, which will be executed when errors or exceptions occur during the execution of those applications in order to minimize the bad infection. This model supports nested scopes and the number of levels of subtransactions is unlimited.
Practical implications
The paper also presents an implementation of this transaction model, which is specialized for context‐aware use.
Originality/value
This paper utilized a novel transaction model to manage the quality of context‐aware applications. The authors have not seen similar work on this topic.
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Increasing longevity and lower birth rates put pressure on the sustainability of pension systems. This compels countries to reform pension schemes. Different countries opt for…
Abstract
Purpose
Increasing longevity and lower birth rates put pressure on the sustainability of pension systems. This compels countries to reform pension schemes. Different countries opt for different types of reforms. This article examines the scope of possibilities for a pension reform in two countries with distinct institutional and ideational setup: Finland and France.
Design/methodology/approach
The authors utilise the framework of different modes of justification presented by Boltanski and Thévenot to reveal the reasoning used in pension reform discussions in both countries. The authors study expert reports to analyse how nationally constructed ideas and local institutions frame and shape the different logics and justifications.
Findings
In Finland, the approach to pensions is dominated by industrial and market justifications. The pension system is institutionally separated into two different blocks: one addressing poverty and the other income maintenance. The separation enables the prevalence of these logics and makes it easier to promote reforms that emphasize efficiency and individual responsibility instead of income distribution. The French report is concentrated around civic and domestic dominated justifications by stressing solidarity and the role of pension systems connecting individuals and generations together. Any reform needs to consider these issues.
Originality/value
The article uses a novel research design to study pension reform processes. The article distinguishes the roles that ideas and institutions have in shaping expert reasoning and reform options. The authors show how ideas and institutions form a mutually reinforcing loop which helps to explain path-dependency in pension systems.