JWSR, Volume 3, Number 3, July-September 2006
Official Publication of the Information Resources Management Association
Published: Quarterly in Print and Electronically
ISSN: 1545-7362
EISSN: 1546-5004


EDITORIAL PREFACE:

"Web Services in Access, Control, and Pricing"

Liang-Jie Zhang, IBM T.J. Watson Research Center, USA

This issue of the International Journal of Web Services research (JWSR) collects five papers on various topics of Web services.

RESEARCH PAPERS

PAPER ONE:

"Supporting Predictable Service Provision in MANETs Via Context-Aware Session Management"

Handorean, R.
Sen, R.
Hackmann, G.
Roman, G.

The increasing ubiquity of wireless mobile devices is promoting unprecedented levels of electronic collaboration among devices interoperating to achieve a common goal. Issues related to host interoperability are addressed partially by the principles of the service-oriented computing paradigm. However, certain technical concerns relating to predictable interactions among hosts in mobile ad hoc networks (MANETs) have not yet received much attention. We introduce follow-me sessions, where interactions occur between a client and a service, rather than a specific service provider. A client, thus, may exploit several service providers during the course of its interaction with a given service. This redundancy mitigates the effects of mobility-induced disconnections, thereby facilitating reliable communication. The switching of service providers is done using a combination of strong process migration, context-sensitive binding and locationagnostic communication protocols. This paper covers the architecture and implementation of a middleware that supports follow-me sessions and shows how this middleware mitigates issues related to proxy-based service-oriented architectures in mobile ad hoc networks. We support our claims via technical evaluation of our approach.

To obtain a copy of the entire article, click on the link below.
http://www.igi-pub.com/articles/details.asp?ID=6319

PAPER TWO:

"An Adaptive Access Control Model for Web Services"

Bertino, E.
Squicciarini, A. C.
Martino, L.
Paci, F.

This paper presents an innovative access control model, referred to as Web service Access Control Version 1 (Ws-AC1), specifically tailored to Web services. The most distinguishing features of this model are the flexible granularity in protection objects and negotiation capabilities. Under Ws-AC1, an authorization can be associated with a single service and can specify for which parameter values the service can be authorized for use, thus providing a fine access control granularity. Ws-AC1 also supports coarse granularities in protection objects in that it provides the notion of service class under which several services can be grouped. Authorizations can then be associated with a service class and automatically propagated to each element in the class. The negotiation capabilities of Ws-AC1 are related to the negotiation of identity attributes and the service parameters. Identity attributes refer to information that a party requesting a service may need to submit in order to obtain the service. The access control policy model of Ws-AC1 supports the specification of policies in which conditions are stated, specifying the identity attributes to be provided and constraints on their values. In addition, conditions may also be specified against context parameters, such as time. To enhance privacy and security, the actual submission of these identity attributes is executed through a negotiation process. Parameters may also be negotiated when a subject requires use of a service with certain parameters values that, however, are not authorized under the policies in place. In this paper, we provide the formal definitions underlying our model and the relevant algorithms, such as the access control algorithm. We also present an encoding of our model in the Web Services Description Language (WSDL) standard for which we develop an extension, required to support Ws-AC1.

To obtain a copy of the entire article, click on the link below.
http://www.igi-pub.com/articles/details.asp?ID=6320

PAPER THREE:

"Facilitating the Specification of Semantic Web Services Using Model-Driven Development"

Gannod, G. C.
Timm, J. T. E.
Brodie, R. J.

The Semantic Web promises automated invocation, discovery, and composition of Web services by enhancing services with semantic descriptions. An upper ontology for Web services called OWL-S has been created to provide a mechanism for describing service semantics in a standard, well-defined manner. Unfortunately, the learning curve for semantic-rich description languages such as OWL-S can be steep, especially given the current state of tool support for the language. This paper describes a suite of automated software tools that we have developed to facilitate the construction of OWL-S specifications. The tools operate in two stages. In the first stage, a model-driven architecture technique is used to generate an OWL-S description of a Web service from a Unified Modeling Language (UML) model. This allows the developer to focus on creating a model of the Web service in a standard UML tool, leveraging existing knowledge. In the second stage, an interactive approach for generating groundings is used. This paper describes both tools and demonstrates how the use of lightweight interactive tools facilitates creation of OWL-S specifications.

To obtain a copy of the entire article, click on the link below.
http://www.igi-pub.com/articles/details.asp?ID=6321

PAPER FOUR:

"Auction-Based Pricing Model for Web Service Providers"

Zhang, J.
Zhang, N.
Zhang, L.-J.

Applying auctions to Web services selection and invocation calls for examination due to the unique features of Web services, such as interoperable machine-to machine interactions and re-enterable bargaining services. In this paper, we propose a formal model for Web services-based auctions. Examining a one sided sealed auction type, we prove mathematically that service requestors?risk preferences could lead to different pricing strategies for service providers towards higher profit. We argue that Service Level Agreement (SLA) documents can be used to analyze service requestors?preferences. On top of WS Agreement, we propose a basic service requestor risk preference elicitation algorithm, as well as a historical data-based service requestor risk preference prediction model. Guidelines are provided to iteratively approach the learning rate of the proposed risk preference prediction model. The methods and techniques presented in this paper can be reused to investigate and examine more facades of services-oriented auctions towards establishing a new research realm on comprehensive services-oriented auctions.

To obtain a copy of the entire article, click on the link below.
http://www.igi-pub.com/articles/details.asp?ID=6322

PAPER FIVE:

"A Service-Oriented Composition Framework with QoS Management"

Fung, C. K.
Hung, P. C. K.
Linger, R. C.
Wang, G.
Walton, G. H.

Quality of Services (QoS) management in compositions of services requires careful consideration of QoS characteristics of the services and effective QoS management in their execution. This paper describes an approach to implementation of QoS management in compositions of Web services in the context of Computational Quality Attributes and Service Level Agreements. Building on prior research work of others in the use of Message Detail Records, this paper integrates the results from several research threads to propose a QoS Management Architecture to support dynamic processing of service- and flow level quality attributes to support QoS requests and analyses in Web-service-oriented architectures. The study of QoS management in a Web service composition framework was motivated by the evolution of the composition framework for a toolkit for integration and experimentation of distributed system applications. A message tracking model is proposed for supporting QoS end-to-end management by applying the Computational Quality Attribute (CQA) concepts of Flow-Service-Quality engineering. Quality attributes are defined, computed and acted upon as dynamic characteristics of systems, with values constantly changing in operation. A CQA provision is illustrated, with a simple Web Services travel reservation example. The example is elaborated to illustrate QoS end-to-end management using the Simple Object Access Protocol (SOAP) message tracking model.

To obtain a copy of the entire article, click on the link below.
http://www.igi-pub.com/articles/details.asp?ID=6323

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For full copies of the above articles, check for this issue of the International Journal of Web Services Research (JWSR) in your Institution's library.
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