基于Web服务的会话模型及其比较和应用研究

Web服务的基础规范仅支持具有简单交互协议的服务调用，不能支持需要交换一系列消息交换的复杂的电子商务交互。文中首先提出了基于Web服务的会话和会话模型的概念，试图用它们来解决双方或多方之间复杂的多步骤的长运行期的交互问题，然后从新兴的描述Web服务的会话性的各种标准归纳出两种会话模型，并对它们进行了详细的分析、应用和比较，最后给出基于会话的企业问应用集成模型，综合应用了基于这两种会话模型的标准。     

Putting the "Web" into Web services. Web services interaction models.2

For pt.1 see ibid., vol.6, no.3, p. 89-91 (2002). As I discussed in my previous column, each different style of middleware promotes one or more interaction models that determine how applications based on that middleware communicate and work with each other. It is difficult to say what the best interaction models would be for Web services, mainly because the World Wide Web Consortium (W3C) is still developing the architecture. The author considers the use of remote procedure calls, Web services and messaging and interface complexity.     

支持感知上下文网络操作平台中间件的研究

普适计算的出现将大大改变人类与各种设备交互的方式。支持感知上下文计算的网络操作平台是普适计算环境下重要的应用支撑平台,为基于传感器网络的应用提供操作服务。操作平台以中间件为核心,采用XMLWebServices技术。文章以满足包括智能家居普适上下文应用需求的网络操作平台为基础,介绍该网络操作平台的机制、层次结构和数据模型的研究,并实现了基于该平台模型的XMLWebServices中间件应用方案。     

Timed Specification For Web Services Compatibility Analysis

Web services are becoming one of the main technologies for designing and building complex inter-enterprise business applications. Usually, a business application cannot be fulfilled by one Web service but by coordinating a set of them. In particular, to perform a coordination, one of the important investigations is the compatibility analysis. Two Web services are said compatible if they can interact correctly. In the literature, the proposed frameworks for the services compatibility checking rely on the supported sequences of messages. The interaction of services depends also on other properties, such that the exchanged data flow. Thus, considering only supported sequences of messages seems to be insufficient. Other properties on which the services interaction can rely on, are the temporal constraints. In this paper, we focus our interest on the compatibility analysis of Web services regarding their (1) supported sequences of messages, (2) the exchanged data flow, (3) constraints related to the exchanged data flow and (4) the temporal requirements. Based on these properties, we study three compatibility classes: (i) absolute compatibility, (ii) likely compatibility and (iii) absolute incompatibility.     

WEBGOP: collaborative web services based on graph-oriented programming

WEBGOP is a programming architecture for collaborative Web services using graph-oriented programming. The motivation for the project comes from the realization that the integration of collaborative Web services lacks support. The aim of WEBGOP is to extend the Web from a client-server system to a structured multipoint system. A graph abstraction of the network provides the structure for the integration of Web services and facilitates their configuration and programming. Using WEBGOP, a logical graph representing a virtual-overlay network over the Internet is created to link up collaborative Web services. Web services are individually or jointly invoked through either unicast or multicast messages within the overlay network. All messages are based on the simple-object access protocol (SOAP). This forms an extension of the hypertext transfer protocol (HTTP) to support the distributed invocation of Web services. The Web services on different servers work collaboratively for a multipoint network application. This project provides a structured integration of Web services by extending the support of intermediary processing in a multipoint service. It also provides a rich network-programming interface for a new class of integrated Web applications while retaining the use of the Internet protocol and HTTP.     

Improving the Dependability of Web Services Integration

The WS-Mediator framework employs an off-the-shelf mediator architecture and resilience-explicit computing in pursuit of dependable, dynamic Web services integration. Web services and service-oriented architectures (SOAs) represent a new paradigm for building distributed computing applications. Web services offer advantages over conventional distributed computing middleware platforms. Web services' loosely coupled architecture, combined with their standardized interoperability, lead to a new computing paradigm that supports the construction of more flexible and dynamic distributed applications     

Web service conversation modeling: a cornerstone for e-business automation

Web services are emerging as a promising technology for effectively automating interorganizational interactions. However, despite the growing interest, several issues remain to be addressed to provide Web services with benefits similar to what traditional middleware brings to intraorganizational application integration. We identify a framework that builds on current standards to help developers define extended service models and richer Web service abstractions. The framework's main feature is a conversation metamodel derived from our analysis of e-commerce portal sites.     

End-to-End QoS Support for a Medical Grid Service Infrastructure

Quality of Service support is an important prerequisite for the adoption of Grid technologies for medical applications. The GEMSS Grid infrastructure addressed this issue by offering end-to-end QoS in the form of explicit timeliness guarantees for compute-intensive medical simulation services. Within GEMSS, parallel applications installed on clusters or other HPC hardware may be exposed as QoS-aware Grid services for which clients may dynamically negotiate QoS constraints with respect to response time and price using Service Level Agreements. The GEMSS infrastructure and middleware is based on standard Web services technology and relies on a reservation based approach to QoS coupled with application specific performance models. In this paper we present an overview of the GEMSS infrastructure, describe the available QoS and security mechanisms, and demonstrate the effectiveness of our methods with a Grid-enabled medical imaging service.     

Development of Web-Telecom based hybrid services orchestration and execution middleware over convergence networks

Influenced by the success of Web service technologies for development and deployment of IT services, Telecom R&D community starts to adapt and build similar service delivery platforms, trying to manage the hard constraints in Telecom domains, such as existence of heterogeneous protocols, extensive use of asynchronous communications and real-time delivery requirements, which will open a new paradigm for Web service based voice over IP communication and also can be easily integrated in end-to-end SOA solutions. In this paper, we study both the Web-Telecom based hybrid services orchestration and execution middleware for coordinating existing Telecom services and IT services. In particular, we focus on the design and implementation Web-Telecom based hybrid service bus (WTSB), event-driven Telecom service engine (EDLE) and also the integration layer for the messages dispatching and transformation between WTSB and EDLE, which can make the EDLE service engine seamlessly integrated into WTSB. More specifically, with multimedia conferencing scenarios, we demonstrate how our hybrid services orchestration and execution middleware orchestrate multimedia conferencing communication services together, and also make performance measurement and analysis. Finally, we give the conclusions and future work.     

基于中间件的电子商务服务集成

提出了一种将CORBA、基于XML的信息交换中间件以及Web Services3种中间件相结合的方法，在松耦合和紧耙合两个层面上实现电子商务服务的集成。CORBA用于企业内部的服务集成，WebServices用于Web上的服务集成，而信息交换中间件则在内外集成系统之间起到信息及功能的桥接作用。     

分布对象中间件StarBus

文章在介绍分布对象中间件技术及其应用情况的基础上,针对CAD领域中产品数据管理系统中的系统集成问题,着重介绍了基于分布对象中间件系统-StarBus3.0的主要功能,包括进行应用系统集成的通信“软总线”、系统服务、Web连接器等相关技术。     

Ruby Extensions

Using languages such as Ruby for middleware integration projects is straightforward when developers can create pure dynamic language applications that access preexisting services, even though such services (often considered "legacy") are typically implemented in "traditional" middleware languages such as Java, C++, or C. Are dynamic languages like Ruby still useful in situations that require directly coupling the dynamic code to the legacy code? Here, Vinoski explores what it takes to cleanly integrate Ruby into an existing C++ middleware system.     

Integration with Web services

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.     

基于MS BizTalk服务器实现数据集成

研究MSBizTalkServer作为数据传输和系统接口中间件在现有遗留系统和新开发应用数据集成中的应用.以石化行业应用系统的数据交换平台为例,数据交换的设计基于三层体系结构,采用.NET技术实现,数据交换核心采用XML数据标准,接口标准采用Web Services,在系统安全性、负载均衡上也提出适用的方法.     

Efficient allocation of resources in multiple heterogeneous Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are useful for a wide range of applications, from different domains. Recently, new features and design trends have emerged in the WSN field, making those networks appealing not only to the scientific community but also to the industry. One such trend is the running different applications on heterogeneous sensor nodes deployed in multiple WSNs in order to better exploit the expensive physical network infrastructure. Another trend deals with the capability of accessing sensor generated data from the Web, fitting WSNs in novel paradigms of Internet of Things (IoT) and Web of Things (WoT). Using well-known and broadly accepted Web standards and protocols enables the interoperation of heterogeneous WSNs and the integration of their data with other Web resources, in order to provide the final user with value-added information and applications. Such emergent scenarios where multiple networks and applications interoperate to meet high level requirements of the user will pose several changes in the design and execution of WSN systems. One of these challenges regards the fact that applications will probably compete for the resources offered by the underlying sensor nodes through the Web. Thus, it is crucial to design mechanisms that effectively and dynamically coordinate the sharing of the available resources to optimize resource utilization while meeting application requirements. However, it is likely that Quality of Service (QoS) requirements of different applications cannot be simultaneously met, while efficiently sharing the scarce networks resources, thus bringing the need of managing an inherent tradeoff. In this paper, we argue that a middleware platform is required to manage heterogeneous WSNs and efficiently share their resources while satisfying user needs in the emergent scenarios of WoT. Such middleware should provide several services to control running application as well as to distribute and coordinate nodes in the execution of submitted sensing tasks in an energy-efficient and QoS-enabled way. As part of the middleware provided services we present the Resource Allocation in Heterogeneous WSNs (SACHSEN) algorithm. SACHSEN is a new resource allocation heuristic for systems composed of heterogeneous WSNs that effectively deals with the tradeoff between possibly conflicting QoS requirements and exploits heterogeneity of multiple WSNs.     

Analyzing conversations of Web services

A composite Web service consists of a set of individual services (or peers), which interact with each other via messages. A conversation is a global sequence of messages exchanged among peers participating in a composite Web service. Interestingly, conversation behavior differs significantly for synchronous and asynchronous communication, even if peers' local behaviors remain the same. The authors use synchronizability and realizability analysis techniques to analyze conversations in the presence of asynchronous communication. With these analyses, they can use model checking to automatically verify conversation behavior for bottom-up and top-down Web service specifications.     

Service Mosaic: A Model-Driven Framework for Web Services Life-Cycle Management

Although Web services provide abstractions for simplifying integration at lower levels of the interaction stacks, they don't yet help simplify integration at higher abstraction levels such as business-level interaction protocols. Using a model-driven framework for Web services life-cycle management, the authors help facilitate the scalable development and maintenance of service-oriented applications by analyzing and managing Web service business protocols. Instead of using simple black and white measures,they identify different classes of protocol compatibility and replaceability. They implemented this framework in a prototype platform called Service Mosaic.     

Integrating and customizing heterogeneous e-commerce applications

A broad spectrum of electronic commerce applications is currently available on the Web, providing services in almost any area one can think of. As the number and variety of such applications grow, more business opportunities emerge for providing new services based on the integration and customization of existing applications. (Web shopping malls and support for comparative shopping are just a couple of examples.) Unfortunately, the diversity of applications in each specific domain and the disparity of interfaces, application flows, actor roles in the business transaction, and data formats, renders the integration and manipulation of applications a rather difficult task. In this paper we present the Application Manifold system, aimed at simplifying the intricate task of integration and customization of e-commerce applications. The scope of the work in this paper is limited to web-enabled e-commerce applications. We do not support the integration/customization of proprietary/legacy applications. The wrapping of such applications as web services is complementary to our work. Based on the emerging Web data standard, XML, and application modeling standard, UML, the system offers a novel declarative specification language for describing the integration/customization task, supporting a modular approach where new applications can be added and integrated at will with minimal effort. Then, acting as an application generator, the system generates a full integrated/customized e-commerce application, with the declarativity of the specification allowing for the optimization and verification of the generated application. The integration here deals with the full profile of the given e-commerce applications: the various services offered by the applications, the activities and roles of the different actors participating in the application (e.g., customers, vendors), the application flow, as well as with the data involved in the process. This is in contrast to previous works on Web data integration that focused primarily on querying the data available in the applications, mostly ignoring the additional aspects mentioned above. Received: 30 October 2000 / Accepted 14 March 2001 Published online: 2 August 2001     

Visual Grid Workflow in Triana

In this paper, we describe the graphical abstractions for Grids and services that have been implemented within the Triana problem solving environment. We provide an overview of the ways in which Triana interacts with services (e.g., Web and P2P services) and then how we interact with core Grid components, such as resource managers and data management systems through the extensive use of the GridLab GAT interface. We describe in detail the GAT philosophy and implementation and then show how the various GAT primitives can be represented in an intuitive fashion within a Triana workflow. This approach, which we refer to as the Visual GAT, differs substantially from other approaches because we do not tie our implementation to any specific underlying Grid middleware technologies; rather, we base our implementation on application level requirements and model such primitives from a user’s perspective by hiding as much complexity as possible without undermining the core capabilities required. We provide a use case to demonstrate the Visual GAT implementation and show how legacy applications can seamlessly be distributed and integrated in a dynamic fashion within complex data-driven workflow scenarios.