Improving data perturbation testing techniques for Web services

The widespread use of service-oriented architectures (SOAs) and Web services in commercial software requires the adoption of development techniques to ensure the quality of Web services. Testing techniques and tools concern quality and play a critical role in accomplishing quality of SOA based systems. Existing techniques and tools for traditional systems are not appropriate to these new systems, making the development of Web services testing techniques and tools required. This article presents new testing techniques to automatically generate a set of test cases and data for Web services. The techniques presented here explore data perturbation of Web services messages upon data types, integrity and consistency. To support these techniques, a tool (GenAutoWS) was developed and applied to real problems.     

SECO: mediation services for semantic Web data

SECO (semantic collaboration), an infrastructure that lets agents uniformly access data that is potentially scattered across the Web is described. The SECO system provides mediation services that aggregate, integrate, and display RDF data obtained from the semantic Web. Using a crawler, SECO collects the RDF data available in files and uses RDF repositories as data sources. SECO applies semantic Web technologies to RDF data by combining techniques from information retrieval and semistructured databases.     

Scalable filtering of XML data for Web services

As the Web gains prevalence as an application-to-application communication medium, organizations are deploying more Web service applications to provide standardized, programmatic application functionality over the Internet. The paper considers how scalable content-based routing architectures for Web applications can handle the growing number of XML messages associated with Web services.     

Model-based engineering for change-tolerant systems

Developing and evolving today’s systems are often stymied by the sheer size and complexity of the capabilities being developed and integrated. At one end of the spectrum, we have sophisticated agent-based software with hundreds of thousands of collaborating nodes. These require modeling abstractions relevant to their complex workflow tasks as well as predictable transforms and mappings for the requisite elaborations and refinements that must be accomplished in composing these systems. At the other end of the spectrum, we have ever-increasing capabilities of reconfigurable hardware devices such as field-programmable gate arrays to support the emerging adaptability and flexibility needs of these systems. From a model-based engineering perspective, these challenges are very similar; both must move their abstraction and reuse levels up to meet growing productivity and quality objectives. Model-based engineering and software system variants such as the model-driven architecture (MDA) are increasingly being applied to systems development as the engineering community recognizes the benefits of managing complexity, separating key concerns, and automating transformations from high-level abstract requirements down through the implementation. However, there are challenges when it comes to establishing the correct boundaries for change-tolerant parts of the system. Capabilities engineering (CE) is a promising approach for defining long-lived components of a system to ensure some sense of change tolerance. For innovative initiatives such as the National Aeronautics and Space Administration (NASA)’s autonomous nanotechology swarms (ANTS), the development and subsequent evolution of such systems are of considerable importance as their missions involve complex, collaborative behaviors across distributed, reconfigurable satellites. In this paper, we investigate the intersection of these two technologies as they support the development of complex, change-tolerant systems. We present an effective approach for bounding computationally independent models so that, as they transition to the architecture, capabilities-based groupings of components are relevant to the change-tolerant properties that must convey in the design solution space. The model-based engineering approach is validated via a fully functional prototype and verified by generating nontrivial multiagent systems and reusing components in subsequent systems. We build off of this research completed on the collaborative agent architecture, discuss the CE approach for the transition to architecture, and then examine how this will be applied in the reconfigurable computing community with the new National Science Foundation Center for High-Performance Reconfigurable Computing. Based on this work and extrapolating from similar efforts, the model-based approach shows promise to reduce the complexities of software evolution and increase productivity—particularly as the model libraries are populated with canonical components.     

Model-based clustering for longitudinal data

A model-based clustering method is proposed for clustering individuals on the basis of measurements taken over time. Data variability is taken into account through non-linear hierarchical models leading to a mixture of hierarchical models. We study both frequentist and Bayesian estimation procedures. From a classical viewpoint, we discuss maximum likelihood estimation of this family of models through the EM algorithm. From a Bayesian standpoint, we develop appropriate Markov chain Monte Carlo (MCMC) sampling schemes for the exploration of target posterior distribution of parameters. The methods are illustrated with the identification of hormone trajectories that are likely to lead to adverse pregnancy outcomes in a group of pregnant women.     

Efficient execution of composite Web services exchanging intensional data

Web service technologies provide a standard means of integrating heterogeneous applications distributed over the Internet. Successive compositions of new Web services using pre-existing ones usually create a hierarchical structure of invocations among a large number of Web services. For the efficient execution of these composite Web services, we propose an approach which exploits intensional XML data, i.e. an XML document that contains special elements representing the calls to Web services, in order to delegate the invocations of the external Web services to some relevant nodes. We formalize an invocation plan for composite Web services in which intensional data is used as their parameters and results, and define a cost-based optimization problem to obtain an efficient invocation plan for them. We provide an A∗ heuristic search algorithm to find an optimal invocation plan for a given set of Web services and also present a greedy method of generating an efficient solution in a short time. The experimental results show that the proposed greedy method can find a close-to-optimal solution efficiently and has good scalability for a complex call hierarchy of Web services.     

基于变异的Web复合服务测试数据选择方法

Web服务集成测试的测试数据数量巨大,影响了测试的质量和效率。提出一种基于变异技术的Web复合服务测试数据选择方法,根据BPEL(Business Process Execution Language)文档获取复合服务的路径集,采用接口变异算子和路径变异算子生成变异体,根据初始测试数据杀死变异体的能力选择有效的测试数据。通过实验验证了方法的有效性,选择出的测试数据数量较少且有效。     

Model-based services convergence and multi-clouds integration

With the development of cloud computing, IT users (individuals, enterprises and even public services providers) are transferring their jobs or businesses to public online services provided by professional information service companies. These information service companies provide applications as public resources to support the business operation of their customers. However, no cloud computing service vendor (CCSV) can satisfy the full functional information system requirements of its customers. As a result, its customers often have to simultaneously use services distributed in different clouds and do some connectivity jobs manually. Services convergence and multi-clouds integration will lead to new business models and trigger new integration technologies that provide solutions to satisfy IT users’ complicated requirements. This paper firstly reviews the development of cloud computing from business and technical viewpoints and then discusses requirements and challenges of services convergence and multi-clouds integrations. Thirdly, a model based architecture of multi-clouds integration is provided. Business logic modelling for cross-organizational collaboration, service modelling and operation modelling methods with relative model mapping technology are discussed in detail. Some key enabling technologies are also developed. At last, case studies are presented to illustrate the implementation of the technologies developed in the paper.     

语义Web服务——Web服务的扩展

语义Web服务是应用语义Web技术对Web服务的扩展.使信息具有语义就是用计算机内的Ontology中的概念作标记符对信息进行标记,对该过程予以支持的就是语义Web技术,即Ontology的构建技术、Ontology的使用技术(语义推理技术)和信息的语义标记技术.语义Web技术对Web服务的扩展可具体化为两项任务:服务提供者、服务请求者和服务注册处三类服务主体均内置Ontology;发布、查找和绑定三种交互信息均采用语义标记.     

Creating GUIs for Web services

Next-generation Web browsers Will have form navigation, variable-size lists, and dynamic enumeration built in to increase user friendliness.     

Model-based reasoning: a principled approach for software engineering

The software engineering industry suffers from almost unmanageable complexity both in the products it produces and in the processes of production. One of the current shortcomings in the software production process is the weakness of the models used. This paper makes observations on the role of knowledge in engineering and examines the central role of models and simulation. We develop an argument for the application of certain new forms of modelling methods in software engineering in order to impose more discipline and give a principled framework for building models that can support the software life-cycle. The concept of a model is examined in depth and different characteristics and types of model are defined. This introduces the relatively new concept of qualitative models and their use in the field known as model-based reasoning. Unlike previous knowledge-based methods, model-based reasoning has several important advantages. Although very few model-based software projects exist, we illustrate how this approach can be developed by drawing on applications from traditional engineering. It is argued that, because qualitative modelling offers great power for addressing the issue of complexity, such models have considerable potential as high-level abstractions of software products. These could form the core of tools for the management and support of the software development process through the whole product life-cycle.     

基于模型的Web用户行为分析的大数据分析框架

虽然基本的Web分析工具非常普遍,目前的分析工具只分析页面级别的用户交互,为了加深对用户行为的理解,该研究提出了将Web应用程序与运行时日志相结合的方法.实现对web应用程序的日志以及用户与页面的交互的跟踪,达到了基于大数据的用户行为分析和可视化.     

Model-based monitoring and policy enforcement of services

Runtime monitoring is necessary for continuous quality assurance of Web Services. Sensors are critical in runtime monitoring to capture the data and detect anomalies. However, sensors in current monitoring systems are usually manually instrumented or hard-coded in the program. It is expensive to implement, and inflexible to change at runtime. The paper extends our previous research on collaborative monitoring and proposes a model-based approach for automatic generating sensors and enforcing policies. Web Services standards WSDL and OWL-S are taken as the models of service interface, workflow, and semantic. Sensors are generated based on the models from two perspectives: (1) dependency analysis of the data, operations, and services with respect to the ontology model of domain concepts and usage context; (2) coverage strategies to decide the specific logic and paths to cover and the data to capture by the monitoring sensors. Policies are defined as a 3-tuple of type, subject and assertion sets and are specified using WS-Policy standards. They are associated to the sensors and enforced at runtime by the policy engine that interoperates with service execution engine to communicate runtime behavior information and verification results. Prototype system is implemented based on the Eclipse platform where sensors are implemented as the listeners to the process execution and instrumented into the middleware including the OWL-S execution engine and SOAP engine. Experiments show that the monitoring results in low overhead of the system performance, reduced effort and enhanced flexibility of sensor instrumentation.     

Usage-centered engineering for Web applications

This article describes a flexible, model-driven approach for engineering Web applications that succeeds through a focus on user interface design and usability. Its simple, model-driven techniques work well for novel applications and integrate readily with lightweight or agile development processes under compressed development schedules     

Composing Web services for large-scale tasks

By making it easy to explore combinations of multiple Web services, Eurasia helps users tackle large-scale information-management tasks and adapt and reuse the steps involved.     

Adapting content for wireless Web services

Motorola Labs' Web-enabled museum system demonstrates how context-aware wireless Web services can adapt their content to a user's dynamic context.     

Extending movilog for supporting Web services

Web Services enable computers to interact and exploit Web-accessible programs without human intervention. Despite researchers agree that mobile agent technology will obtain significant benefits from this line of research, the lack of proper development tools hinder the widespread adoption of mobile agent technology on the Web. This paper describes a novel programming language called WS-Log whose goal is to provide a tight integration between mobile agents and Web Services. Examples and experimental results showing some of the advantages of WS-Log are also reported.     

Model-driven trust negotiation for Web services

Trust negotiation is an approach to access control whereby access is granted based on trust established in a negotiation between the service requester and the service provider. Trust negotiation systems avoid several problems facing traditional access control models such as DAC (discretionary access control) and MAC (mandatory access control). Another problem is that Web service providers often do not know requesters identities in advance because of the ubiquitousness of services. We describe Trust-Serv, a trust negotiation framework for Web services, which features a policy language based on state machines. It is supported by lifecycle management and automated runtime enforcement tools. Credential retrieval and validation in Trust-Serv rely on predefined Web services that provide interactions with attribute assertion authorities and public key infrastructure.