移动计算环境下的个人化服务发布和组装

随着移动计算技术的发展,移动设备用户可以服务的方式共享移动设备及其周围设备的计算能力和计算资源.然而,移动设备的私有性、资源受限性以及移动性等特征使得这种基于移动设备提供的个人化服务在发布和组装方面存在着一些特殊问题,例如用户隐私、移动设备资源消耗、网络环境变化引起的失效问题等.针对以上这些问题,提出一种移动计算环境下的个人化服务发布和组装方法.该方法在个人化服务发布过程中引入了服务意愿的概念,并在服务选择过程中综合考虑了服务意愿和服务效用.此外,还提出了资源感知的心跳机制来定期更新服务选择所依赖的设备及服务状态信息,从而解决由于网络环境变化等引起的服务失效问题.基于该方法,提出了一个基于JADE和OSGi的实现框架.通过一个案例分析,验证了所提出的实现框架的有效性以及在移动计算环境下考虑服务意愿的合理性.     

移动环境下基于移动代理的应用框架设计

随着网络技术的发展和移动设备的普及，用户希望能随时随地对资源进行访问。但是，由于移动网络连接带宽低且移动单元本身资源贫乏，移动环境为分布应用开发提出了新的挑战。移动代理技术以其节省带宽、异步性等特征，为移动计算提供了良好的解决方案。本文首先讨论了移动代理系统的设计，然后提出一个基于移动代理的移动应用框架
架，最后给出了相应的应用实例。     

Mobile agent middleware for mobile computing

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     

面向普适计算环境的Android平台服务编排框架

普适计算环境下的智能移动设备是面向终端用户的服务资源聚集和编排的主要载体。普适计算环境中的服务资源具有多种不同的形态,包括基于互联网提供的Web服务、终端设备自身服务和资源(例如本地应用、自带传感器)以及所处环境中可访问的服务(例如环境传感器)。此外,不断变化的上下文环境对软件本身的自适应能力提出了新的要求,而移动设备上的服务编排受设备计算能力和资源的限制。为了解决上述问题,提出了一个面向普适计算环境的Android平台服务编排框架ASOF。通过ASOF,移动终端可在运行时获取所需业务流程的服务模板,并对该模板中的抽象服务进行服务绑定,实现轻量级的混合服务编排,使终端能够动态获得调用普适计算环境中各种类型的服务的能力。随后,基于OSGi Felix框架给出了一套ASOF的标准实现,并以一个具体案例验证其有效性。     

A testing framework for mobile computing software

We present a framework for testing applications for mobile computing devices. When a device is moved into and attached to a new network, the proper functioning of applications running on the device often depends on the resources and services provided locally in the current network. This framework provides an application-level emulator for mobile computing devices to solve this problem. Since the emulator is constructed as a mobile agent, it can carry applications across networks on behalf of its target device and allow the applications to connect to local servers in its current network in the same way as if they had been moved with and executed on the device itself. This paper also demonstrates the utility of this framework by describing the development of typical network-dependent applications in mobile and ubiquitous computing settings.     

The FUSE Platform: Supporting Ubiquitous Collaboration Within Diverse Mobile Environments

The recent proliferation of heterogeneous computing devices and wireless network technology presents new opportunities for Computer Supported Cooperative Work (CSCW). One emergent paradigm is that of ubiquitous collaboration, which provides widespread access to shared services through a variety of interactive devices, irrespective of whether individuals are mobile or deskbound. However, developing groupware that is interoperable across diverse, often mobile, environments can be difficult and costly. The fundamental issue is that current support infrastructures, which will meet the requirements for multi-user application development, are not operable within emerging ubiquitous settings. This paper explores this problem and presents a generic platform that promotes new forms of collaboration through mobility and ever-present computing services. The developed platform seeks to provide a wide range of collaborative services to a very diverse set of devices by adapting and extending existing middleware technologies.     

A location model for smart environments

This paper presents a location model for location-aware and user-aware services in smart environments. It can be dynamically organized like a tree based on geographical containment, such as that in a user–room–floor–building hierarchy and each node in the tree can be constructed as an executable software component. The model is unique in existing approaches because it enables location-aware services to be managed without any database servers, it can be managed by multiple computers, and it can provide a unified view of the locations of not only physical entities and spaces, including users and objects, but also computing devices and services. A prototype implementation of this approach was constructed on a Java-based mobile agent system. This paper presents the rationale, design, implementation, and applications of the prototype system.     

Towards Mobile Cloud Computing with Single Sign-on Access

The low computing power of mobile devices impedes the development of mobile applications with a heavy computing load. Mobile Cloud Computing (MCC) has emerged as the solution to this by connecting mobile devices with the “infinite” computing power of the Cloud. As mobile devices typically communicate over untrusted networks, it becomes necessary to secure the communications to avoid privacy-sensitive data breaches. This paper presents work on implementing MCC applications with secure communications. For that purpose, we built on COMPSs-Mobile, a redesigned implementation of the COMP Superscalar (COMPSs) framework aiming to MCC platorms. COMPSs-Mobile automatically exploits the parallelism inherent in an application and orchestrates its execution on loosely-coupled distributed environment. To avoid a vendor lock-in, this extension leverages on the Generic Security Services Application Program Interface (GSSAPI) (RFC2743) as a generic way to access security services to provide communications with authentication, secrecy and integrity. Besides, GSSAPI allows applications to take profit of more advanced features, such as Federated Identity or Single Sign-On, which the underlying security framework could provide. To validate the practicality of the proposal, we use Kerberos as the security services provider to implement SSO; however, applications do not authenticate themselves and require users to obtain and place the credentials beforehand. To evaluate the performance, we conducted some tests running an application on a smartphone offloading tasks to a private cloud. Our results show that the overhead of securing the communications is acceptable.     

On Composite Web Services Provisioning in an Environment of Fixed and Mobile Computing Resources

We present a framework for Web services provisioning in a hybrid environment of fixed and mobile computing resources. Several obstacles still hinder the seamless provisioning of Web services in mobile environments. Examples of such obstacles are: throughput and connectivity of wireless networks, limited computing resources of mobile devices, and risks of communication channel disconnections. In the proposed framework, software agents represent users, providers of services, and providers of resources. The business logic of composite services is expressed as a process model using statecharts formalism. Among other things, the use of agents provides an infrastructure that has the ability to handle disconnections during service preparation for execution. The framework also integrates a service execution planning approach to optimally select computing resources (fixed or mobile) on top of which services will be executed.     

An open and scalable architecture for delivering 3D shared visualization services to heterogeneous devices

Shared visualization environments represent an effective means to enhance collaborative work in engineering and scientific design tasks. The availability of high‐speed networks allows researchers to work together from geographically distributed locations, and mobile devices are able to carry out ubiquitous 3D visualization tasks through wireless network connections. This paper presents a scalable architecture for the delivery of shared 3D visualization services to heterogeneous terminals ranging from powerful workstations to mobile devices such as PDAs and smart‐phones. The framework design allows both desktop and mobile clients to simultaneously visualize the same model by sharing a common view. Remote‐rendering servers support effective visualization on thin clients, and a load balancing mechanism provides efficient resource usage. Copyright © 2011 John Wiley & Sons, Ltd.     

Deploying personalized mobile services in an agent-based environment

The mobile Internet allows users to obtain digitized contents and services from wired and wireless networks virtually anywhere at any time via different handheld mobile devices. However, due to the distinct features of mobile users, mobile devices and wireless networks, deploying mobile services is not as straightforward as generally expected. To ensure the success of mobile services, this paper presents a multi-agent framework that considers different contexts to support personalized services on wireless networks. In the proposed approach, client users, content providers, and service providers are all considered as software agents. They interoperate on the same platform to request and deliver mobile services. The most important issues related to agent operations and context awareness in an agent world are also discussed and analyzed. To verify our framework, different application services are developed accordingly on a publicly available middleware platform. Experiments are conducted for both services to evaluate their corresponding performance. The preliminary results show that our multi-agent approach to personalization is promising and efficient in the deployment of mobile services.     

An ECA-based framework for decentralized coordination of ubiquitous web services

Emerging ubiquitous computing network is expected to consist of a variety of heterogeneous and distributed devices. While web services technology is increasingly being considered as a promising solution to support the inter-operability between such heterogeneous devices via well-defined protocol, currently there is no effective framework reported in the literature that can address the problem of coordinating the web services-enabled devices. This paper considers a ubiquitous computing environment that is comprised of active, autonomous devices interacting with each other through web services, and presents an ECA (Event-Condition-Action)-based framework for effective coordination of those devices. Specifically, we first present an XML-based language for describing ECA rules that are embedded in web service-enabled devices. An ECA rule, when triggered by an internal or external event to the device, can result in the invocation of appropriate web services in the system. Subsequently, we consider the situation in which the rules are introduced and managed by multiple, independent users, and propose effective mechanisms that can detect and resolve potential inconsistencies among the rules. The presented ECA-based coordination approach is expected to facilitate seamless inter-operation among the web service-enabled devices in the emerging ubiquitous computing environments.     

Design, analysis, and deployment of omnipresent Formal Trust Model (FTM) with trust bootstrapping for pervasive environments

The rapid decrease in the size of mobile devices, coupled with an increase in capability, has enabled a swift proliferation of small and very capable devices into our daily lives. With such a prevalence of pervasive computing, the interaction among portable devices needs to be continuous and invisible to device users. As these devices become better connected, collaboration among them will play a vital role in sharing resources in an ad-hoc manner. The sharing of resources works as a facilitator for pervasive devices. However, this ad hoc interaction among devices provides the potential for security breaches. Trust can fight against such security violations by restricting malicious nodes from participating in interactions. Therefore, we need a unified trust relationship model between entities, which captures both the needs of the traditional computing world and the world of pervasive computing where the continuum of trust is based on identity, physical context or a combination of both. Here, we present a context specific and reputation-based trust model along with a brief survey of trust models suitable for peer-to-peer and ad-hoc environments. This paper presents a multi-hop recommendation protocol and a flexible behavioral model to handle interactions. One other contribution of this paper is the integration of an initial trust model; this model categorizes services or contexts in different security levels based on their security needs, and these security needs are considered in trust bootstrapping. The other major contribution of this paper is a simple method of handling malicious recommendations. This paper also illustrates the implementation and evaluation of our proposed formal trust model.     

DaaS: Cloud-based mobile Web service discovery

The proliferation of smartphones and the recent advancement in ubiquitous wireless access have made mobile Web services more possible than ever before. However, finding relevant Web services that can match requests and fit user context remains a major concern. The challenges facing Web service discovery are further magnified by the stringent constraints of mobile devices and the inherit complexity of wireless heterogeneous networks. Cloud computing, with its flexible design and theoretically unlimited computing resources, is a viable approach to bootstrapping Web service discovery. The cloud can build bridges between mobile devices, as a convenient ubiquitous interface, and a backbone infrastructure with abundant computing resources. This paper introduces “Discovery as a service (Daas)”, a novel cloud-based discovery framework that addresses the core components of mobile Web service discovery. The DaaS framework lays the foundation of efficient mobile Web service discovery that takes into consideration user preferences and context. The experimental validation and performance evaluation demonstrate that DaaS can effectively rank relevant services according to the various user context and preferences, in addition to enhancing the precision of the discovered services. The prototype also shows that Web service clustering for discovery significantly improves the overall response time, while the cloud maintains scalability according to prespecified performance criteria.     

Diagnosing diabetes using neural networks on small mobile devices

Pervasive computing is often mentioned in the context of improving healthcare. This paper presents a novel approach for diagnosing diabetes using neural networks and pervasive healthcare computing technologies. The recent developments in small mobile devices and wireless communications provide a strong motivation to develop new software techniques and mobile services for pervasive healthcare computing. A distributed end-to-end pervasive healthcare system utilizing neural network computations for diagnosing illnesses was developed. This work presents the initial results for a simple client (patient’s PDA) and server (powerful desktop PC) two-tier pervasive healthcare architecture. The computations of neural network operations on both client and server sides and wireless network communications between them are optimized for real time use of pervasive healthcare services.     

The ECORA framework: A hybrid architecture for context-oriented pervasive computing

An infrastructure approach to support context-aware pervasive computing is advantageous for rapid prototyping of context-aware distributed applications and beneficial for unifying modelling of context and reasoning in uncertain conditions. This paper presents the ECORA framework for context-aware computing, which is designed with a focus on reasoning about context under uncertainty and addressing issues of heterogeneity, scalability, communication and usability. The framework follows an agent-oriented hybrid approach, combining centralized reasoning services with context-aware, reasoning capable mobile software agents. The use of a centralized reasoning engine provides powerful reasoning capabilities and deploying context-aware mobile agents enables agility and robustness of components in the pervasive system. The design and implementation of the framework at different levels, as well as three case studies, are presented.     

A lightweight active service migration framework for computational offloading in mobile cloud computing

Cloud computing enables access to the widespread services and resources in cloud datacenters for mitigating resource limitations in low-potential client devices. Computational cloud is an attractive platform for computational offloading due to the attributes of scalability and availability of resources. Therefore, mobile cloud computing (MCC) leverages the application processing services of computational clouds for enabling computational-intensive and ubiquitous mobile applications on smart mobile devices (SMDs). Computational offloading frameworks focus on offloading intensive mobile applications at different granularity levels which involve resource-intensive mechanism of application profiling and partitioning at runtime. As a result, the energy consumption cost (ECC) and turnaround time of the application is increased. This paper proposes an active service migration (ASM) framework for computational offloading to cloud datacenters, which employs lightweight procedure for the deployment of runtime distributed platform. The proposed framework employs coarse granularity level and simple developmental and deployment procedures for computational offloading in MCC. ASM is evaluated by benchmarking prototype application on the Android devices in the real MCC environment. It is found that the turnaround time of the application reduces up to 45 % and ECC of the application reduces up to 33 % in ASM-based computational offloading as compared to traditional offloading techniques which shows the lightweight nature of the proposed framework for computational offloading.     

面向富互联网应用的计算任务动态迁移机制

富互联网应用(rich Internet application,RIA)目前已经成为重要的应用模式.随着信息技术日益泛在化和服务化,富互联网应用也开始在移动设备之上运行.然而,由于设备计算能力的不足,很可能出现部分代码无法在富客户端顺利运行的情况.提出面向富互联网应用的计算任务动态迁移机制,在应用运行过程中,动态地将...     

Clairvoyance: A framework to integrate shared displays and mobile computing devices

Supporting formal and informal meetings with digital information and ubiquitous software systems every day becomes increasingly mandatory. These meetings require that the integration of devices participating in the meeting and the information flow among them should be done as seamless as possible to avoid jeopardizing the natural interactions among participants. Trying to contribute to address such a challenge, this article presents a framework that allows devices integration and smooth information flow. This framework, named Clairvoyance, particularly integrates mobile computing devices and large-screen TVs through a mobile ad hoc network, and thus it eases the implementation of shared displays intended to be used in formal and informal meetings. Clairvoyance provides a set of services through an API, which can be used to develop ubiquitous applications that support meetings in particular scenarios. The preliminary evaluation of this framework considered its usage to implement a ubiquitous system that supports social meetings among friends or relatives. According to developers, the framework is easy to use and it provided all required services for such an application. The solution obtained was then utilized by end-users in simulated meetings. The evaluation results indicate that the Clairvoyance services were suitable to support the informal meetings, and that the devices integration and information flow were transparent for the end-users.     

Design and implementation of a smart system for personalization and accurate selection of mobile services

Wireless mobile services are computing applications that run on handheld wireless devices. Such applications must work within the daunting constraints of the devices, which include memory, processing power, input capabilities, and size of display. It is therefore important that mobile services take into account the user’s context, optimize resource usage, and minimize input effort imposed on the user. In this paper, we present the design and implementation of a smart agent-enabled system for personalizing wireless mobile services and advertisements for Java 2 Micro Edition (J2ME) or Java ME, and Wireless Application Protocol (WAP) enabled devices. We use software agents for context filtering because such autonomous software entities have characteristics that can benefit mobile devices and the wireless environment, and the Composite Capability/Preference Profiles (CC/PP) standard for defining profiles for user preferences and device capabilities. The system incorporates the use of artificial neural networks to adaptively and iteratively learn to select the best available service based on contextual information. The system is evaluated using practical operating scenarios, as well as empirical data and results show an 87% success rate in the selection of the best available service.