共查询到20条相似文献,搜索用时 31 毫秒
1.
为了提高普适计算系统的开发效率, 设计了一个基于OSGi框架的动态普适计算中间件模型. 该中间件模型以OSGi框架为基础, 建立移动管理器管理用户和服务的移动, 利用上下文管理器来管理上下文, 动态调整自己的行为, 支持上下文感知应用. 通过标准的接口实现各种异构普适设备间的互操作性. 实验结果表明该中间件能够满足通用普适计算环境的要求, 对于普适计算系统的开发具有一定的借鉴意义. 相似文献
2.
一个适用于遍在计算环境的中间件体系结构框架 总被引:1,自引:0,他引:1
1.背景随着计算技术和通信技术的发展,不仅桌式计算机变得非常普遍,非PC设备正以惊人的速度成为市场的主流,如:机顶盒、移动电话、PDA、家用电器、汽车电子、游戏机等等。特别是随着家庭网络和无线网络的发展,网络变得更加的普遍。计算已经不只限于桌面,它渗透到人们生活和工作的各个环节,这就是所谓的无处不在的计算环境(pervasive computing,简称遍在计算环境)。在这样的环境中,人们希望:即使他们在频繁地移动,或者各种资源在动态地加入或离开,他 相似文献
3.
A mobility-aware dynamic database caching scheme for wireless mobile computing and communications 总被引:2,自引:0,他引:2
This paper describes a mobility-aware dynamic database caching scheme for wireless mobile computing and communications. A mobile-floating agent scheme is proposed, in which caching techniques are cognizant of the mobile nature of mobile users and the location-sensitive nature of mobile systems. The mobile-floating agent maintains a second class cache in the fixed network and employs Barbara's invalidation reports broadcasting cache consistency strategies to maintain a dynamic cache consistent with the first class cache in the mobile client. The invalidation reports broadcasting scheme is combined with knowledge of the mobility behavior of each individual mobile user and broadcasts of invalidation reports only occur within the user's mobility area. The evaluation results show that, for a large system (200 cells), this scheme can reduce the system cost by more than 87%, for even highly mobile users, compared with a fully replicated database system.Recommended by: Daniel Barbara, Ravi Jain and Narayanan Krishnakumar 相似文献
4.
5.
Realizing the potential of pervasive computing will be predicated upon the availability of a flexible, mobility-aware infrastructure and technologies to support seamless service management, provisioning and delivery. Despite advances in routing and media access control technologies, little progress has been made towards large-scale deployment of services and applications in pervasive and ubiquitous environments. The lack of a fixed infrastructure, coupled with the time-varying characteristics of the underlying network topology, makes service delivery challenging. This paper addresses these challenges and presents SARA, a unified, overlay-based service architecture to support large-scale service and application deployment in pervasive and ubiquitous environments. We discuss the main functionalities of SARA and present the algorithms for object registration and discovery. SARA also considers the mobility of the nodes in the network and provides a mechanism by which this can be incorporated into the framework. Finally, the proposed architecture was evaluated using simulations and the results show that the architecture performs well under different network conditions. 相似文献
6.
Charles L. Isbell Jr Olufisayo Omojokun Jeffrey S. Pierce 《Personal and Ubiquitous Computing》2004,8(3-4):146-153
One of the driving applications of ubiquitous computing is universal appliance interaction: the ability to use arbitrary mobile devices to interact with arbitrary appliances, such as TVs, printers, and lights. Because of limited screen real estate and the plethora of devices and commands available to the user, a central problem in achieving this vision is predicting which appliances and devices the user wishes to use next in order to make interfaces for those devices available. We believe that universal appliance interaction is best supported through the deployment of appliance user interfaces (UIs) that are personalized to a users habits and information needs. In this paper, we suggest that, in a truly ubiquitous computing environment, the user will not necessarily think of devices as separate entities; therefore, rather than focus on which device the user may want to use next, we present a method for automatically discovering the users common tasks (e.g., watching a movie, or surfing TV channels), predicting the task that the user wishes to engage in, and generating an appropriate interface that spans multiple devices. We have several results. We show that it is possible to discover and cluster collections of commands that represent tasks and to use history to predict the next task reliably. In fact, we show that moving from devices to tasks is not only a useful way of representing our core problem, but that it is, in fact, an easier problem to solve. Finally, we show that tasks can vary from user to user. 相似文献
7.
8.
9.
There's a difference between what we'd like our enterprise computing systems to be and what they really are. We like to envision them as orderly multitier arrangements comprising software buses, hubs, gateways, and adapters - all deployed at just the right places to maximize scale, load, application utility, and ultimately, business value. Unfortunately, we know that there's a wide gulf between this idealistic vision and reality. In practice, our enterprise computing systems typically are tangles of numerous technologies, protocols, and applications, often hastily hard-wired together with inflexible point-to-point connections. The whole point of middleware is to hide the diversity and complexity of the computing machinery underneath it. By adopting the abstractions that middleware provides, we're supposedly isolating our applications from the variety of ever-changing hardware platforms, operating systems, networks, protocols, and transports that make up our enterprise computing systems. We can use Web services to provide "middleware for middleware" abstraction layer for modern integration applications. 相似文献
10.
11.
Threads play a key role in object‐based middleware platforms. Implementers of such platforms can select either kernel or user‐level threads, but neither of these options are ideal. In this paper we introduce Application Scheduler Contexts (ASCs) which flexibly combine both types of thread and thereby attempt to exploit the advantages of each. Multiple ASCs can co‐exist, each with their own concurrency semantics and scheduling policy. ASCs also support quality of service (QoS) configurability, and define their own QoS schema. We show how ASCs can be efficiently implemented and how they can usefully be exploited in middleware environments. We also provide a quantitative evaluation that demonstrates the feasibility of the ASC concept in performance terms. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
12.
Currently distributes systems support different computing paradigms like Cluster Computing, Grid Computing, Peer-to-Peer Computing, and Cloud Computing all involving elements of heterogeneity. These computing distributed systems are often characterized by a variety of resources that may or may not be coupled with specific platforms or environments. All these topics challenge today researchers, due to the strong dynamic behavior of the user communities and of resource collections they use.The second part of this special issue presents advances in allocation algorithms, service selection, VM consolidation and mobility policies, scheduling multiple virtual environments and scientific workflows, optimization in scheduling process, energy-aware scheduling models, failure Recovery in shared Big Data processing systems, distributed transaction processing middleware, data storage, trust evaluation, information diffusion, mobile systems, integration of robots in Cloud systems. 相似文献
13.
This paper presents Arcademis, a Java‐based framework for communication middleware development. Arcademis consists of a set of abstract classes, interfaces and concrete components that define the general architecture of middleware systems. Its main objective is to support the implementation of non‐monolithic and easily configurable middleware platforms. Arcademis can be used by middleware developers to deploy systems that meet the requirements of a particular network or technology. Instances of Arcademis can also be customized by distributed systems engineers to meet the requirements of a particular application. For example, new transport protocols, connection management policies, authentication algorithms or invocation semantics can be easily configured in middleware platforms derived from Arcademis. In order to illustrate the use of the framework, the paper describes the RME system, a middleware derived from Arcademis that adds a remote method invocation service to the CLDC configuration of Java 2 Micro Edition (J2ME). Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
14.
The increasing user mobility demands placed upon IT services necessitates an environment that enables users to access optimal
services at any time and in any place. This study presents research conducted to develop a system that is capable of analyzing
user IT service patterns and tendencies and provides the necessary service resources by sharing each user’s context information.
First, each user’s context information is gathered to provide the multi-agent software training data necessary to describe
user operations in a hybrid peer-to-peer (P2P) structured communication environment. Next, the data collected about each user’s
mobile device is analyzed through a Bayesian based neural network system to identify the user’s tendency and extract essential
service information. This information provides a communication configuration allowing the user access to the best communication
service between the user’s mobile device and the local server at any time and in any place, thereby enhancing the ubiquitous
computing environment. 相似文献
15.
基于JavaRMI技术的移动中间件存在一定程度的局限性。文中以中间件、分布对象计算和移动计算等相关领域的技术为背景,提出了基于分布对象技术的移动中间件MMDO(MobileMiddlewareBasedonDistributedObject),该体系结构包括:动态可定制的基础核心、通用移动Agent平台、异步消息服务、动态资源发现和移动用户安全注册。MMDO能够解决移动中间件研究存在的Java效率问题,同时拓展了移动服务,给移动应用提供更好的支撑环境。最后,给出仿真测试结果,证明了MMDO的有效性。 相似文献
16.
Dan Hong Dickson K. W. Chiu Vincent Y. Shen S. C. Cheung Eleanna Kafeza 《Information Systems Frontiers》2007,9(4):343-358
Recent advances in mobile technologies and infrastructures have created the demand for ubiquitous access to enterprise services
from mobile handheld devices. Further, with the invention of new interaction devices, the context in which the services are
being used becomes an integral part of the activity carried out with the system. Traditional human–computer interface (HCI)
theories are now inadequate for developing these context-aware applications, as we believe that the notion of context should
be extended to different categories: computing contexts, user contexts, and physical contexts for ubiquitous computing. This
demands a new paradigm for system requirements elicitation and design in order to make good use of such extended context information
captured from mobile user behavior. Instead of redesigning or adapting existing enterprise services in an ad hoc manner, we
introduce a methodology for the elicitation of context-aware adaptation requirements and the matching of context-awareness
features to the target context by capability matching. For the implementation of such adaptations, we propose the use of three
tiers of views: user interface views, data views, and process views. This approach centers on a novel notion of process views
to ubiquitous service adaptation, where mobile users may execute a more concise version or modified procedure of the original
process according to their behavior under different contexts. The process view also serves as the key mechanism for integrating
user interface views and data views. Based on this model, we analyze the design and implementation issues of some common ubiquitous
access situations and show how to adapt them systematically into a context-aware application by considering the requirements
of a ubiquitous enterprise information system.
相似文献
Eleanna KafezaEmail: |
17.
Traditional use of grid computing allows a user to submit batch jobs in a grid environment. We believe, next generation grids will extend the application domain to include interactive graphical sessions. We term such grids Interactive Grids. In this paper, we describe some of the challenges involved in building Interactive Grids. These include fine grain access control, performance QoS guarantees, dynamic account management, scheduling, and user data management. We present the key architectural concepts in building Interactive Grids viz. hierarchical sessions, hierarchical admission control, hierarchical agents, classes of dynamic accounts, application profiling, user data management, scheduling for interactive sessions, persistent environment settings, and exporting remote desktop. We also describe IGENV, an environment for enabling interactive grids. IGENV consists of GISH –Grid Interactive Shell, Controlled Desktop, SAC –Session Admission Control module, GMMA –Grid Monitoring and Management Agents, and Policy Engine. We also present our testbed implementation for Interactive Grids using and extending Globus Toolkit 2.0 for the Grid middleware infrastructure, and VNC as the remote display technology. 相似文献
18.
The vision of ubiquitous computing is becoming a reality thanks to the advent of portable devices and the advances in wireless networking technologies. It aims
to facilitate user tasks through seamless utilization of services available in the surrounding environments. In such distributed
environments featuring openness, interactions such as service provision and consumption between entities that are unknown
or barely known to each other, are commonplace. Trust management through reputation mechanism for facilitating such interactions
is recognized as an important element of ubiquitous computing. It is, however, faced by the problems of how to stimulate reputation
information sharing and enforce honest recommendation elicitation. We present in this paper an incentive compatible reputation
mechanism to facilitate the trustworthiness evaluation of entities in ubiquitous computing environments. It is based on probability
theory and supports reputation evolution and propagation. Our reputation mechanism not only shows robustness against lies,
but also stimulates honest and active recommendations. The latter is realized by ensuring that active and honest recommenders,
compared to inactive or dishonest ones, can obtain the most number of honest (helpful) recommendations and thus suffer the
least number of wrong trust decisions, as validated by simulation based evaluation. The proposed reputation mechanism is also
implemented as part of a QoS-aware Web service discovery middleware and evaluated regarding its overhead on service discovery
latency. 相似文献
19.
In recent years, due to the emergence of ubiquitous computing technology, a new class of networked robots called ubiquitous robots has been introduced. The Ubiquitous Robotic Companion (URC) is our conceptual vision of ubiquitous service robots that provides its user with the services the user needs, anytime and anywhere, in the ubiquitous computing environments. There are requirements to be met for the vision of URC. One of the essential requirements is that the robotic systems must support ubiquity of services. This means that a robot service must always be available even though there are changes in the service environment. More specifically, a robotic system needs to be interoperable with sensors and devices in its current service environments automatically, rather than statically pre-programmed for its environment. In this paper, the design and implementation of an infrastructure for URC called Ubiquitous Robotic Service Framework (URSF) is presented. URSF enables automated integration of networked robots in a ubiquitous computing environment by the use of Semantic Web Services Technologies. 相似文献