Result Refinement in Web Services Retrieval Based on Multiple Instances Learning

Web services retrieval is a critical step for reusing existing services in the SOA paradigm. In the UDDI registry, traditional category-based approaches have been used to locate candidate services. However, these approaches usually achieve relatively low precision because some candidate Web Services in the result set cannot provide actually suitable operations for users. In this article, we present a new approach to improve this kind of category-based Web Services retrieval process that can refine the coarse matching results step by step. The refinement is based on the idea that operation specification is very important to service reuse. Therefore, a Web Service is investigated via multiple instances view in our approach, which indicates that a service is labeled as positive if and only if at least one operation provided by this service is usable to the user. Otherwise, it is labeled as negative. Experimental results demonstrate that our approach can increase the retrieval precision to a certain extent after one or two rounds of refinement.

A Model-Driven Development Framework for Non-Functional Aspects in Service Oriented Architecture

Service oriented architecture (SOA) is an emerging style of software architectures to reuse and integrate existing systems for designing new applications. Each application is designed in an implementation independent manner using two major abstract concepts: services and connections between services. In SOA, non-functional aspects (e.g., security and fault tolerance) of services and connections should be described separately from their functional aspects (i.e., business logic) because different applications use services and connections in different non-functional contexts. This paper proposes a model-driven development (MDD) framework for non-functional aspects in SOA. The proposed MDD framework consists of (1) a Unified Modeling Language (UML) profile to model non-functional aspects in SOA, and (2) an MDD tool that transforms a UML model defined with the proposed profile to application code. Empirical evaluation results show that the proposed MDD framework improves the reusability and maintainability of service-oriented applications by hiding low-level implementation technologies in SOA.

Business Process Control-Flow Complexity

Organizations are increasingly faced with the challenge of managing business processes, workflows, and recently, Web processes. One important aspect of business processes that has been overlooked is their complexity. High complexity in processes may result in poor understandability, errors, defects, and exceptions, leading processes to need more time to develop, test, and maintain. Therefore, excessive complexity should be avoided. Business process measurement is the task of empirically and objectively assigning numbers to the properties of business processes in such a way so as to describe them. Desirable attributes to study and measure include complexity, cost, maintainability, and reliability. In our work, we will focus on investigating process complexity. We present and describe a metric to analyze the control-flow complexity of business processes. The metric is evaluated in terms of Weyuker’s properties in order to guarantee that it qualifies as good and comprehensive. To test the validity of the metric, we describe the experiment we have carried out for empirically validating the metric.

Security Personalization for Internet and Web Services

The growth of the Internet has been accompanied by the growth of Internet services (e.g., e-commerce, e-health). This proliferation of services and the increasing attacks on them by malicious individuals have highlighted the need for service security. The security requirements of an Internet or Web service may be specified in a security policy. The provider of the service is then responsible for implementing the security measures contained in the policy. However, a service customer or consumer may have security preferences that are not reflected in the provider’s security policy. In order for service providers to attract and retain customers, as well as reach a wider market, a way of personalizing a security policy to a particular customer is needed. We derive the content of an Internet or Web service security policy and propose a flexible security personalization approach that will allow an Internet or Web service provider and customer to negotiate to an agreed-upon personalized security policy. In addition, we present two application examples of security policy personalization, and overview the design of our security personalization prototype.

Karma2

The increasing ability for the sciences to sense the world around us is resulting in a growing need for datadriven e-Science applications that are under the control of workflows composed of services on the Grid. The focus of our work is on provenance collection for these workflows that are necessary to validate the work-flow and to determine quality of generated data products. The challenge we address is to record uniform and usable provenance metadata that meets the domain needs while minimizing the modification burden on the service authors and the performance overhead on the workflow engine and the services. The framework is based on generating discrete provenance activities during the lifecycle of a workflow execution that can be aggregated to form complex data and process provenance graphs that can span across workflows. The implementation uses a loosely coupled publish-subscribe architecture for propagating these activities, and the capabilities of the system satisfy the needs of detailed provenance collection. A performance evaluation of a prototype finds a minimal performance overhead (in the range of 1% for an eight-service workflow using 271 data products).

XML Security with Binary XML for Mobile Web Services

In the wireless world, there has recently been much interest in alternate serialization formats for XML data, mostly driven by the weak capabilities of both devices and networks. However, it is difficult to make an alternate serialization format compatible with XML security features such as encryption and signing. We consider here ways to integrate an alternate format with security, and present a solution that we see as a viable alternative. In addition to this, we present extensive performance measurements, including ones on a mobile phone on the effect of an alternate format when using XML-based security. These measurements indicate that, in the wireless world, reducing message sizes is the most pressing concern, and that processing efficiency gains of an alternate format are a much smaller concern. We also make specific recommendations on security usage based on our measurements.

Interoperability Among Heterogeneous Services

Service-oriented computing (SOC) has been marked as the technology trend that caters for interoperability among the components of a distributed system. However, the emergence of various incompatible instantiations of the SOC paradigm, e.g. Web or peer-to-peer services (P2P), and the divergences encountered within each of these instantiations state clearly that interoperability is still an open issue, mainly due to its multi-dimensional nature. In this paper we address the interoperability problem by first presenting its multiple dimensions and then by describing a conceptual model called generic service model (GeSMO), which can be used as a basis for the development of languages, tools and mechanisms that support interoperability. We then illustrate how GeSMO has been utilized for the provision of a P2P service description language and a P2P invocation mechanism which leverages interoperability between heterogeneous P2P services and between P2P services and Web services.

Workflow Discovery

Much has been written on the promise of Web service discovery and (semi-) automated composition. In this discussion, the value to practitioners of discovering and reusing existing service compositions, captured in workflows, is mostly ignored. We present the case for workflows and workflow discovery in science and develop one discovery solution. Through a survey with 21 scientists and developers from the myGrid/Taverna workflow environment, workflow discovery requirements are elicited. Through a user experiment with 13 scientists, an attempt is made to build a benchmark for workflow ranking. Through the design and implementation of a workflow discovery tool, a mechanism for ranking workflow fragments is provided based on graph sub-isomorphism detection. The tool evaluation, drawing on a corpus of 89 public workflows and the results of the user experiment, finds that, for a simple showcase, the average human ranking can largely be reproduced.

DSCWeaver

Correct synchronization among activities is critical in a business process. Current process languages such as BPEL specify the control flow of processes procedurally, which can lead to inflexible and tangled code for managing a crosscutting aspect—synchronization constraints that define permissible sequences of execution for activities. In this article, we present DSCWeaver, a tool that enables a synchronization-aspect extension to procedural languages. It uses DSCL (directed-acyclic-graph synchronization constraint language) to achieve three desirable properties for synchronization modeling: fine granularity, declarative syntax, and validation support. DSCWeaver then automatically generates executable code for synchronization. We demonstrate the advantages of our approach in a service deployment process written in BPEL and evaluate its performance using two metrics: lines of code (LoC) and places to visit (PtV). Evaluation results show that our approach can effectively reduce the development effort of process programmers while providing performance competitive to unwoven BPEL code.

Data Mining in Web Services Discovery and Monitoring

The business needs, the availability of huge volumes of data and the continuous evolution in Web services functions derive the need of application of data mining in the Web service domain. This article recommends several data mining applications that can leverage problems concerned with the discovery and monitoring of Web services. This article then presents a case study on applying the clustering data mining technique to the Web service usage data to improve the Web service discovery process. This article also discusses the challenges that arise when applying data mining to Web services usage data and abstract informat