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Code mobility is recognized as a promising design technique, able to improve flexibility, adaptability and bandwidth utilization in mobile computing applications. To promote and facilitate its use, researchers argue that code mobility should be made available to programmers in combination with, and not as an alternative to, more traditional programming models. This paper describes the design and implementation of the MobileRMI toolkit which, unlike agent-based systems, enables mobility-based programming within a widely accepted middleware platform, Java Remote Method Invocation (RMI). Our toolkit provides a set of mobility primitives that allow programmers to create, clone and move remote objects across a network. To preserve location transparency we implemented a novel, efficient scheme for automatically updating remote references by exploiting the distributed garbage collector. Programming examples are given and a case study where an adaptive application uses logical mobility to minimize communication over a mobile ad hoc network is presented. Experience from using MobileRMI confirmed the benefit of designing both static and mobile applications within the same programming framework. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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K. Geihs P. Barone F. Eliassen J. Floch R. Fricke E. Gjorven S. Hallsteinsen G. Horn M. U. Khan A. Mamelli G. A. Papadopoulos N. Paspallis R. Reichle E. Stav 《Software》2009,39(4):385-422
Driven by the emergence of mobile and pervasive computing there is a growing demand for context‐aware software systems that can dynamically adapt to their run‐time environment. We present the results of project MADAM that has delivered a comprehensive solution for the development and operation of context‐aware, self‐adaptive applications. The main contributions of MADAM are (a) a sophisticated middleware that supports the dynamic adaptation of component‐based applications, and (b) an innovative model‐driven development methodology that is based on abstract adaptation models and corresponding model‐to‐code transformations. MADAM has demonstrated the viability of a general, integrated approach to application‐level adaptation. We discuss our experiences with two real‐world case studies that were built using the MADAM approach. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Capra L. Emmerich W. Mascolo C. 《IEEE transactions on pattern analysis and machine intelligence》2003,29(10):929-945
Mobile devices, such as mobile phones and personal digital assistants, have gained wide-spread popularity. These devices will increasingly be networked, thus enabling the construction of distributed applications that have to adapt to changes in context, such as variations in network bandwidth, battery power, connectivity, reachability of services and hosts, etc. In this paper, we describe CARISMA, a mobile computing middleware which exploits the principle of reflection to enhance the construction of adaptive and context-aware mobile applications. The middleware provides software engineers with primitives to describe how context changes should be handled using policies. These policies may conflict. We classify the different types of conflicts that may arise in mobile computing and argue that conflicts cannot be resolved statically at the time applications are designed, but, rather, need to be resolved at execution time. We demonstrate a method by which policy conflicts can be handled; this method uses a microeconomic approach that relies on a particular type of sealed-bid auction. We describe how this method is implemented in the CARISMA middleware architecture and sketch a distributed context-aware application for mobile devices to illustrate how the method works in practice. We show, by way of a systematic performance evaluation, that conflict resolution does not imply undue overheads, before comparing our research to related work and concluding the paper. 相似文献
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Julien C. Roman G.-C. 《IEEE transactions on pattern analysis and machine intelligence》2006,32(5):281-298
Today's mobile applications require constant adaptation to their changing environments, or contexts. Technological advances have increased the pervasiveness of mobile computing devices such as laptops, handhelds, and embedded sensors. The sheer amount of context information available for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this data-rich environment requires a middleware that provides context information to applications in an abstract form. In this paper, we demonstrate the feasibility of such a middleware that allows programmers to focus on high-level interactions among programs and to employ declarative abstract context specifications in settings that exhibit transient interactions with opportunistically encountered components. We also discuss the novel context-aware abstractions the middleware provides and the programming knowledge necessary to write applications using it. Finally, we provide examples demonstrating the infrastructure's ability to support differing tasks from a wide variety of application domains. 相似文献
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Mobile computing requires an advanced infrastructure that integrates suitable support protocols, mechanisms, and tools. This mobility middleware should dynamically reallocate and trace mobile users and terminals and permit communication and coordination of mobile entities. In addition, open and untrusted environments must overcome system heterogeneity and grant the appropriate security level. Solutions to these issues require compliance with standards to interoperate with different systems and legacy components and a reliable security infrastructure based on standard cryptographic mechanisms and tools. Many proposals suggest using mobile agent technology middleware to address these issues. A mobile agent moves entities in execution together with code and achieved state, making it possible to upgrade distributed computing environments without suspending service. We propose three mobile computing services: user virtual environment (UVE), mobile virtual terminal (MVT), and virtual resource management (VRM). UVE provides users with a uniform view of their working environments independent of current locations and specific terminals. MVT extends traditional terminal mobility by preserving the terminal execution state for restoration at new locations, including active processes and subscribed services. VRM permits mobile users and terminals to maintain access to resources and services by automatically requalifying the bindings and moving specific resources or services to permit load balancing and replication 相似文献
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上下文相关技术已经成为普适计算环境中用于应用服务的不可或缺的核心技术之一。对于基于构件的中间件来说,对高性能的上下文管理的需求更是必不可少,因为它构成了普适计算环境中构件适配和部署的重要基础。因此,在已有构件中间件的基础上,我们针对普适计算环境的特点提出了一种整体的上下文管理方法,将上下文管理集成在已有的构件化中间件中。应用表明,该方法能够更好地支持普适计算环境下上下文相关的构件化应用开发。 相似文献
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《Computer Networks》1999,31(7):741-765
Existing mobile systems (e.g., mobile IP, mobile ATM and third generation cellular systems) lack the intrinsic architectural flexibility to deal with the complexity of supporting adaptive mobile applications in wireless and mobile environments. We believe that there is a need to develop alternative network architectures from the existing ones to deal with the demands placed on underlying mobile signalling, adaptation management and wireless transport systems in support of new mobile services, e.g. interactive multimedia and web access. In this paper we present the design, implementation and evaluation of mobiware, a middleware technology that enables the introduction of new services in mobile networks. Mobiware provides a toolkit that service providers can utilize to build services that can dynamically exploit the intrinsic scalable properties of mobile multimedia applications in response to time-varying mobile network conditions. Based on an open programmable networking paradigm, mobiware runs on mobile devices, wireless access points and mobile-capable switch/routers providing a set of open programmable interfaces and distributed objects for adaptive mobile networking. Mobiware is software-intensive and is built on CORBA and Java distributed object technologies. The source code for mobiware v1.0 is freely available (comet.columbia.edu/mobiware) for experimentation. 相似文献
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《Journal of Network and Computer Applications》2010,33(5):569-587
The mobile computing paradigm has introduced new problems for application developers. Challenges include heterogeneity of hardware, software, and communication protocols, variability of resource limitations and varying wireless channel quality. In this scenario, security becomes a major concern for mobile users and applications. Security requirements for each application are different, as well as the hardware capabilities of each device. To make things worse, wireless medium conditions may change dramatically with time, incurring great impact on performance and QoS guarantees for the application. Currently, most of the security solutions for mobile devices use a static set of algorithms and protocols for services such as cryptography and hashes.In this work we propose a security service, which works as a middleware, with the ability to dynamically change the security protocols used between two peers. These changes can occur based on variations on wireless medium parameters and system resource usage, available hardware resources, application-defined QoS metrics, and desired data “security levels”. We compare our solution to some widespread static security protocols, demonstrate how our middleware is able to adapt itself over different conditions of medium and system, and how it can provide a performance gain in the execution of cryptographic primitives, through the use of data semantics. 相似文献
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传统中间件基于黑盒的设计思想,缺乏必要的灵活性,无法适应复杂动态多变的移动计算环境。反射技术可以使应用程序在运行时检查中间件所提供的服务类型,动态的构造调用请求,适应变化的环境。文章研究了反射的相关概念,中间件技术,分析了移动计算的实际需求,提出了一个支持移动计算的反射中间件架构,支持环境感知、异步通信、动态重配置等。 相似文献
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Chan A.T.S. Siu-Nam Chuang 《IEEE transactions on pattern analysis and machine intelligence》2003,29(12):1072-1085
Traditionally, middleware technologies, such as CORBA, Java RMI, and Microsoft's DCOM, have provided a set of distributed computing services that essentially abstract the underlying network services to a monolithic "black box." In a mobile operating environment, the fundamental assumption of middleware abstracting a unified distributed service for all types of applications operating over a static network infrastructure is no longer valid. In particular, mobile applications are not able to leverage the benefits of adaptive computing to optimize its computation based on current contextual situations. In this paper, we introduce the Mobile Platform for Actively Deployable Service (MobiPADS) system. MobiPADS is designed to support context-aware processing by providing an executing platform to enable active service deployment and reconfiguration of the service composition in response to environments of varying contexts. Unlike most mobile middleware, MobiPADS supports dynamic adaptation at both the middleware and application layers to provide flexible configuration of resources to optimize the operations of mobile applications. Within the MobiPADS system, services (known as mobilets) are configured as chained service objects to provide augmented services to the underlying mobile applications so as to alleviate the adverse conditions of a wireless environment. 相似文献
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The increasing popularity and usage of internet based services makes design of software system complex and their power unlimited in scale. These systems often involve heterogeneous environment and platforms. They continuously evolve in order to meet the changes in technology and business practices. Emergence of information system architecture based on disparate externally provided internet based services warrant incorporation of novel design primitives in the application design. Traditionally popular application design primitives includes separation, abstraction, compression, uniform composition, replication and resource sharing that has evolved and came to vogue based on past experience and expert practice. This work examines and evaluates approaches to incorporation of new and novel unit operations around which applications can be architected, designed and analyzed for the internet computing and big data era. Incidentally it is found that portions of agent technology provides several unit operations such as migration of code and speech-act based responsibility delegation/application composition as application architectural primitives. This work determines extensions to Web Services-Business Process Execution Language (WS-BPEL) programming framework—called as ACtive Internet Application Framework (ACIAF) and is suited for incorporation of novel unit operations such as migration of code and speech-act based component orchestration/application composition to enable construction of next generation information systems. An analysis of merits and demerits of using WS-BPEL technology to realize ACIAF is also carried out here. Code mobility feature of ACIAF is demonstrated using a use case while loosely coupled application design using ACIAF is theoretically discussed. Formal analyzability of mobility behavior of ACIAF application is highlighted based on its conformance to Petri-net formalism. Further formal logical analyzability/interpolatability of individual actions performed by collaborating ACIAF applications is also highlighted. It is argued here that ACIAF shall provide necessary foundation, guidance and motivation for further detailed technical work on several ideas presented to realize next generation information systems. This work firmly establishes extension to WS-BPEL platform as a most viable approach to realize novel architectural primitives to the design and implementation of next generation information systems. 相似文献
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This paper presents an object-oriented, Java-like core language with primitives for distributed programming and explicit code mobility. We apply our formulation to prove the correctness of several optimisations for distributed programs. Our language captures crucial but often hidden aspects of distributed object-oriented programming, including object serialisation, dynamic class downloading and remote method invocation. It is defined in terms of an operational semantics that concisely models the behaviour of distributed programs using machinery from calculi of mobile processes. Type safety is established using invariant properties for distributed runtime configurations. We argue that primitives for explicit code mobility offer a programmer fine-grained control of type-safe code distribution, which is crucial for improving the performance and safety of distributed object-oriented applications. 相似文献
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Advancing mobile computing technologies are enabling ubiquitous personal computing environment. In this paper, we focus on an important problem in such environment: user mobility. In the case of user mobility, a user is free to access his/her personalized service at anytime, anywhere, through any possible mobile/fixed devices. Providing mobility support in this scenario poses a series of challenges. The most essential problem is to preserve the user's access to the same service despite changes of the accessing host or service provider. Existing system-level mobility solutions are insufficient to address this issue since it is not aware of the application semantics. On the other hand, making each application to be mobility-aware will greatly increase the development overhead. We argue that the middleware layer is the best place to address this problem. On one hand, it is aware of application semantics. On the other hand, by building application-neutral mobility functions in the middleware layer, we eliminate the need to make each application mobility-aware. In this paper, we design a middleware framework to support user mobility in the ubiquitous computing environment. Its major mobility functions include user-level handoff management and service instantiation across heterogeneous computing platforms. We validate the major mobility functions using our prototype middleware system, and test them on two multimedia applications (Mobile Video Player and Mobile Audio Player). To maximally approximate the real-world user-mobility scenario, we have conducted experiments on a variety of computing platforms and communication paradigms, ranging from T1-connected high-end PC to handheld devices with wireless networks. The results show that our middleware framework is able to provide efficient user mobility support in the heterogeneous computing environment. 相似文献
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Efficient profile aggregation and policy evaluation in a middleware for adaptive mobile applications
《Pervasive and Mobile Computing》2008,4(5):697-718
There is a large consensus on the need for a middleware to efficiently support adaptation in pervasive and mobile computing. Advanced forms of adaptation require the aggregation of context data and the evaluation of policy rules that are typically provided by multiple sources. This paper addresses the problem of designing the reasoning core of a middleware that supports these tasks, while guaranteeing very low response times as required by mobile applications. Technically, the paper presents strategies to deal with conflicting rules, algorithms that implement the strategies, and algorithms that detect and solve potential rule cycles. A detailed experimental analysis supports the theoretical results and shows the applicability of the resulting middleware in large-scale applications. 相似文献
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Samia Allaoua Chelloug Mohamed A. El-Zawawy 《Intelligent Automation and Soft Computing》2018,24(2):309-318
The Internet of things (IoT) applications span many potential fields. Furthermore, smart homes, smart
cities, smart vehicular networks, and healthcare are very attractive and intelligent applications. In
most of these applications, the system consists of smart objects that are equipped by sensors and
Radio Frequency Identification (RFID) and may rely on other technological computing and paradigm
solutions such as M2M (machine to machine) computing, Wifi, Wimax, LTE, cloud computing, etc. Thus,
the IoT vision foresees that we can shift from traditional sensor networks to pervasive systems, which
deliver intelligent automation by running services on objects. Actually, a significant attention has been
given to designing a middleware that supports many features; heterogeneity, mobility, scalability,
multiplicity, and security. This papers reviews the-state-of-the-art techniques for IoT middleware
systems and reveals an interesting classification for these systems into service and agent-oriented
systems. Therefore two visions have emerged to provide the IoT middleware systems: Via designing
the middleware for IoT system as an eco-system of services or as an eco-system of agents. The most
common feature of the two approaches is the ability to overcome heterogeneity issues. However,
the agent approach provides context awareness and intelligent elements. The review presented in
this paper includes a detailed comparison between the IoT middleware approaches. The paper also
explores challenges that form directions for future research on IoT middleware systems. Some of the
challenges arise, because some crucial features are not provided (or at most partially provided) by the
existing middleware systems, while others have not been yet tackled by current research in IoT. 相似文献
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Nenad Medvidovic Author Vitae Author Vitae 《Journal of Systems and Software》2010,83(6):885-898
Modern software-intensive systems are characterized not only by the movement of data, as has been the case in traditional distributed systems, but also by the movement of users, devices, and code. Developing effective, efficient, and dependable systems in the mobile setting is challenging. Existing architectural principles need to be adapted and novel architectural paradigms devised. In this paper, we give an overview of the intersection of the areas of software architecture and mobility. We consider mobility from two related perspectives: (1) mobile software, which represents the computing functionality designed to migrate across hardware devices at runtime and execute on mobile hardware platforms, and (2) mobile systems, which are computing applications that include mobile software and hardware elements. We study the advances in both these areas, highlight representative existing solutions, and identify several remaining research challenges. 相似文献
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《Automatic Control, IEEE Transactions on》2009,54(7):1490-1503