bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating Learning Management Systems
Authors: Passerini Katia
Published: February 2011

This paper maintains that the use of multimedia content in Web-based instruction — facilitated by the proliferation and standardization of learning management systems (LMS) — calls for the extension of traditional multimedia design and evaluation guidelines to the Web. The compliance with these guidelines needs to be thoroughly evaluated by any institution using (or planning to use) Web-based learning management systems. In addition to providing criteria and examples for the evaluation of these systems, the paper includes a survey instrument that can be used for university-wide assessments of the design effectiveness of technologies that support learning. As an example, the proposed evaluation instrument is applied to a learning management system developed at a large university in the United States. While the assessment refers to one system, the model, the instructional and design evaluation criteria, and the questionnaire are built for use in any organization conducting a formative and summative evaluation or a selection of learning technologies.
E-Learning and New Teaching Scenarios
Authors: Mari Cecilia , Genone Sara , Mari Luca
Published: February 2011

This paper analyzes the reciprocal influences between various teaching methodologies sup¬ported by information and communication technology (ICT) and the teaching objectives that are pursued by means of these methodologies. The authors present the main characteristics of the conceptual model which has led to the definition of the teaching objectives and the results of the experience of the “eLearning@LIUC” project, where the validity of the hypotheses underlying the model has been tested through their application within concrete contexts. They believe that the presented model, with its analysis of the possible correlations between teaching objectives, teaching methodologies, and technological tools, can provide a new awareness of the opportuni¬ties offered by the adoption of ICT in teaching.
Online Behavior Modeling
Authors: Chen Charlie , Ryan Terry , Olfman Lorne
Published: February 2011

Organizations need effective and affordable software training. In face-to-face settings, behavior modeling (BM) is an effective, but expensive, training method. Can BM be employed effectively, and more affordably, for software training in the online environment? An experiment was conducted to compare the effectiveness of online BM with that of face-to-face (F2F) BM for software training. Results indicate that online BM and F2F BM provide essentially the same outcomes in terms of knowledge near transfer, immediate knowledge far transfer, delayed knowledge far transfer, perceived ease of use, perceived usefulness and satisfaction. Observed differences were not significant, nor were their patterns consistent, despite sufficient power in the experimental design to detect meaningful differences. These results suggest that organizations should consider online BM as a primary method of software training.
What Factors Promote Sustained Online Discussions and Collaborative Learning in a Web-Based Course?
Authors: Wang Xinchun
Published: February 2011

Although the pedagogical advantages of online interactive learning are well known, much needs to be done in instructional design of applicable collaborative learning tasks that motivate sustained student participation and interaction. This study investigates the factors that encourage student interaction and collaboration in both process and product oriented computer mediated communication (CMC) tasks in a Web-based course that adopts interactive learning tasks as its core learning activities. The analysis of a post course survey questionnaire collected from three online classes suggest that among others, the structure of the online discussion, group size and group cohesion, strictly enforced deadlines, direct link of interactive learning activities to the assessment, and the differences in process and product driven interactive learning tasks are some of the important factors that influence participation and contribute to sustained online interaction and collaboration.
Web-Based Implementation of the Personalised System of Instruction
Authors: Brinkman Willem-Paul , Rae Andrew , Dwivedi Yogesh Kumar
Published: February 2011

This article presents a case study of a university discrete mathematics course with over 170 students who had access to an online learning environment (OLE) that included a variety of online tools, such as videos, self-tests, discussion boards, and lecture notes. The course is based on the ideas of the personalised system of instruction (PSI) modified to take advantage of an OLE. Students’ learning is examined over a period of two years, and compared with that in a more traditionally taught part of the course. To examine students’ behaviour, learning strategies, attitudes and performance, both qualitative and quantitative techniques were used in a mixed methodology approach, including in-depth interviews (N = 9), controlled laboratory observations (N = 8), surveys (N = 243), diary studies (N = 10), classroom observations, recording online usage behaviour, and learning assessments. The paper aims to increase understanding of whether PSI, supported by an OLE, could enhance student appreciation and achievement as findings suggest.
Course Management Systems
Authors: Lang Teresa , Hall Dianne
Published: February 2011

Development and sale of computer-assisted instructional supplements and course management system products are increasing. Textbook sales representatives use this technology to market textbooks, and many colleges and universities encourage the use of such technology. The use of course management systems in education has been equated to the use of enterprise resource planning software by large businesses. Research findings about the pedagogical benefits of computer-assisted instruction and computer management systems are inconclusive. This study describes an experiment conducted to determine the benefit to students of using course manage-ment systems. The effects of cognition, learning styles, and computer attitude were considered and eliminated to better isolate any differences in performance. Student performance did not improve with the use of the technology.
Utilizing Web Tools for Computer-Mediated Communication to Enhance Team-Based Learning
Authors: Gomez Elizabeth Avery , Wu Dezhi , Passerini Katia , Bieber Michael
Published: February 2011

Team-based learning is an active learning instructional strategy used in the traditional face-to-face classroom. Web-based computer-mediated communication (CMC) tools complement the face-to-face classroom and enable active learning between face-to-face class times. This arti-cle presents the results from pilot assessments of computer-supported team-based learning. The authors utilized pedagogical approaches grounded in collaborative learning techniques, such as team-based learning, and extended these techniques to a Web-based environment through the use of computer-mediated communications tools (discussion Web-boards). This approach was examined through field studies in the course of two semesters at a US public technological university. The findings indicate that the perceptions of team learning experience such as per-ceived motivation, enjoyment, and learning in such a Web-based CMC environment are higher than in traditional face-to-face courses. In addition, our results show that perceived team mem-bers’ contributions impact individual learning experiences. Overall, Web-based CMC tools are found to effectively facilitate team interactions and achieve higher-level learning.
Social Networking Theories and Tools to Support Connectivist Learning Activities
Authors: Pettenati M. C. , Cigognini M. E.
Published: February 2011

This article considers the affordances of social networking theories and tools to build new and effective e-learning practices. We argue that “connectivism” (social networking applied to learning and knowledge contexts) can lead to a reconceptualization of learning in which formal, nonformal, and informal learning can be integrated as to build potentially lifelong learning activities to be experienced in “personal learning environments.” In order to provide a guide in the design, development, and improvement both of personal learning environments and in the related learning activities, we provide a knowledge flow model highlighting the stages of learning and the related enabling conditions. The derived model is applied in a possible scenario of formal learning in order to show how the learning process can be designed according to the presented theory.
Web-Based Collaboration and Decision Making Support
Authors: Karacapilidis Nikos , Tzagarakis Manolis
Published: February 2011

Arguing that a varying level of formality needs to be offered in systems supporting argumentative collaboration, this article proposes an incremental formalization approach that has been adopted in the development of CoPe_it!, a Web-based tool that complies with collaborative principles and practices, and provides members of communities engaged in argumentative discussions and decision making processes with the appropriate means to collaborate towards the solution of diverse issues. According to the proposed approach, incremental formalization can be achieved through the consideration of alternative projections of a collaborative workspace.
Digital Media Performance and Reading Comprehension
Authors: Rodrigues Maria Cristina Azevedo Joly , Martins Ronei Ximenes
Published: February 2011

The information and communication technologies (ICTs) present in the Brazilian education system determine the development of technology literacy among teachers and students, which can be measured by ICT performance. The Technology Performance Scale (EDETEC) is a self-reporting psychometric instrument to verify what the students’ conceptions are about ICT and their performance in using technology tools. Considering the necessity of the acquisition of both technology literacy and reading comprehension skills to use ICT resources, this study aimed to know the ICT performance, reading comprehension achievement, and the possible relations among them. The participants were 63 Brazilian students from K10 and K11. The EDETEC and Cloze Test with options were applied by school and grade. The best ICT performance referred to the concept and productivity tools factor (F2), and the ANCOVA (analysis of covariance) statistic test identified the influence of the grade and genre in it. There was positive correlation between reading comprehension and EDETEC.
Implementing and Sustaining E-Learning in the Workplace
Authors: Berge Zane L. , Giles Lenora
Published: February 2011

New information and communication technology, specifically computer networked systems, create both a demand and an opportunity for businesses to approach training and knowledge management from new perspectives. These new training perspectives are driven by the need for businesses to provide the right training quickly and efficiently and to support knowledge systems that are current, accessible, and interactive. This article will discuss strategic planning in terms of the organizational elements and the e-learning program requirements that are necessary to build a framework in order to institutionalize and sustain e-learning as a core business process. The elements of the organizational framework include leadership, change management strategies, the technology infrastructure, and the organizational structure. The e-learning program requirements include instructional systems, roles and competencies of key staff people, and budgeting. The building blocks in a framework to sustain e-learning and knowledge building start with a foundation laid out by the strategic plan. The next two building blocks of the framework are the organizational support processes and the e-learning and knowledge management system
Adaptive Learning Organizer for Web-Based Education
Authors: Yessad Amel , Faron-Zucker Catherine , Edelweiss Rose Dieng-Kuntz , Laskri Med Tayeb
Published: February 2011

Adaptive learning support for learners becomes very important in the context of increasing re-use of resources from heterogeneous and distributed learning repositories. This paper presents OrPAF, an Adaptive Educational Hypermedia (AEHS) and web-based System which integrates semantic web models and technologies in order to achieve interoperability with e-learning systems. The key feature of OrPAF is the construction of adaptive hypermedia courses: both the course structure and the course content are dynamically generated and adapted to learners. We experimented the realized prototype on learners in order to evaluate the usability of OrPAF and the conceptual capabilities developed by the learners who used it.
Awareness Mechanisms for Web-Based Argumentative Collaboration
Authors: Tzagarakis Manolis , Karousos Nikos , Karacapilidis Nikos
Published: February 2011

Much research has been performed on how computer-based technologies might facilitate awareness among cooperating actors. However, existing approaches in providing awareness services prove to be inadequate in data-intensive instances of argumentative collaboration. Moreover, they fail to address the needs of dynamic, Web-based communities. In this context, this article presents a list of awareness mechanisms that have been integrated in an innovative Web-based collaboration support tool, where the ultimate aim is to satisfy the requirements associated with the above remarks. The proposed mechanisms are described and elaborated with respect to various awareness types reported in the literature.
A Case Study of Ontology-Driven Development of Intelligent Educational Systems
Authors: Deline Gordon , Lin Fuhua , Wen Dunwei , Gaševic Dragan , Kinshuk
Published: February 2011

This article presents a case study of ontology-driven development of intelligent educational systems. Following a review of literature related to ontology development, ontology-driven software development, and traditional software engineering, we developed an ontology-driven software development methodology appropriate for intelligent ontology-driven systems which have ontologies as key execution components, such as e-Advisor, and which is biased toward an integration of incremental and iterative ontology development and downstream Model Driven Architecture for development of software components.
The Blended Learning Ecosystem of an Academic Institution in Greece
Authors: Nikolaidou Mara , Sofianopoulou Chryssa , Alexopoulou Nancy , Abeliotis Kostas , Detsis Vassilis , Chalkias Christos , Lasaridi Katia , Anagnostopoulos Dimosthenis
Published: February 2011

Blended learning has been recognized as the most promising emerging trend in higher education, offering new capabilities, as it may significantly enhance the interaction and communication between instructors and students. The challenge of blended learning is to balance weaknesses and strengths of face-to-face and e-learning teaching environments and effectively combining them to provide enhanced learning capabilities. Its success should benefit instructor-student relation. To this end, the authors adopt ecosystem-based approach to model the blended learning environment and identify its constituents, i.e., instructors, students, consultants, technology. and their evolving relations. The proposed concept was utilized to explore the potential of blended learning in the academic environment. A study was conducted at Harokopio University of Athens over a period of three years to explore the relations between blended learning ecosystem constituents, focusing on instructor -student relation.
Portals and the Challenge of Simplifying Internet Business Use
Authors: Adamson Greg
Published: February 2011

The Internet promised a lot for enterprises from 1995. The Internet’s ubiquity offered inter-company connectivity (previously provided to corporations by Electronic Data Interchange) for businesses of every size. The business-to-business (B2B) trading exchange concept emerged, 10,000 B2B exchanges were anticipated. Early Internet investment then struck an unexpected hurdle: the Internet didn’t inherently support many of the key requirements for business transactions (such as reliability, confidentiality, integrity, authentication of parties). These requirements added to the cost and complexity of Internet investment. The dot.com stock market crash affected all Internet-related initiatives. But while the B2B exchanges disappeared, other initiatives more aligned to user needs and the Internet’s architecture continued to grow. These included the enterprise portal, which supports the traditional single-business-centred customer relationship model, in contrast to the business disruptive B2B exchange model.
Building Portal Applications
Authors: Polgar Jana , Polgar Tony
Published: February 2011

Software development methodology refers to a standardised, documented methodology which has been used before on similar projects or one which is used habitually within an organisation (Software development methodology). It can generally be applied to all kinds of software products. In portlet development process there are new circumstances which affect the methodology. A portal development manager must be aware of the technological properties and constraints, because there is a large (and very new) range of issues, risks and hidden costs that must be addressed in both the development and deployment processes. This article focuses on discussion of practical approaches to the resolution of development issues and risks in Portal environment. The discussed topics include implementation of Portals in enterprise environment, portlet applications’ high availability, portlet disaster recovery, and the cost of portlet deployment. An attempt is made to forecast future trends in portlet technology.
An Overview of REST
Authors: Newmarch Jan
Published: February 2011

The REST approach was developed to describe the architecture of distributed resource access, such as the WEB. REST in comparison with WS_*stack works with the Web rather than against it and is getting increasing support of not only from developers but also from vendors. This paper explains the philosophy of REST and highlights its simplicity in accessing resources.
Service Oriented Architecture Conceptual Landscape
Authors: Young Ed
Published: February 2011

Contemporary architectural approach is for an orchestrated, agnostic, federated enterprise through the adoption of loosely-coupled open Service interfaces. The Service-Oriented Architecture (SOA) paradigm unifies disparate, heterogeneous technologies. It resurrects legacy technology silos with a Service ‘face-lift’ while maintaining their autonomy. Somewhat in its infancy as standards and methodologies are evaluated and adopted, the differences between theory and praxis of SOA remain to be fully determined, predominately due to the size and complexity of the conundrum it addresses.
Search Integration with WebSphere Portal
Authors: Prokoph Andreas
Published: February 2011

Modern web applications and servers like Portal require adequate support for integration of search services due to user focused information delivery and user interaction, as well as new technologies used to render such information, which is exemplified by two fundamental problems that have long plagued web crawlers: dynamic content and Javascript generated content. Today, the solution is simple: ignore such web pages. To enable “search” in Portals, a different “crawling” paradigm is required to search engines to gather and consume information. WebSphere Portal provides a framework that propagates content and information through “Seedlists”—comparable to HTML based sitemaps but richer in terms of features. This mandates that information and content delivering applications must be “search engine aware”, requiring them to enable services and seedlists for fast, efficient and complete delivery of content and information. This is the main integration point for search engines into the portal for Portal site search services for a rich and user focused search experience. This article discusses how such technologies can allow for more efficient crawling of public Portal sites by prominent Internet search engines as well as myths surrounding search engine optimization.
Interview
Authors: Adamson Greg , Noble Rick
Published: February 2011

Not-for-profit organisations are significant users of IT services, including Portals, for the use of public outreach and service delivery. While lacking the resources of the commercial sector, many not-for-profit organisations’ needs may be similarly complex if they are relying on a portal for service delivery to a vulnerable client sector, or for the protection of medical records. In this paper, the authors examine the experience of service delivery to two medium-sized not-for-profits in Melbourne, Australia.
An Extensible Workflow Architecture through Web Services
Authors: Jang Jinyoung , Choi Yongsun , Zhao J. Leon
Published: February 2011

The growing availability of Web services provides a new opportunity for enabling new ways of system integration and interoperability, which are needed to meet the needs of global e-business. In this study, we propose an extensible workflow architecture based on Web services and object-oriented techniques. The proposed architecture contains three components, the Open Kernel Framework, the Universal Resource Manager, and the Process Definition Publisher. We show how this architecture can help extend workflow systems with new features dynamically such as new workflow patterns, new process semantics, new workflow resources, and even new process languages.
QoS-Aware and Federated Enhancement for UDDI
Authors: Zhou Chen , Chia Liang-Tien , Lee Bu-Sung
Published: February 2011

With more and more Web services appearing on the Web, Web service’s discovery mechanisms become essential. UDDI is an online registry standard to facilitate the discovery of business partners and services. Service requesters can choose good performance Web services by manual test and comparison. However, this method of choosing is inefficient and costly in terms of time and money. The ability to predict the quality of service is missing in UDDI. Furthermore, UDDI registries in federated organizations should be able to share more about the service requester’s connection information to make better predictions for services’ performances. To address these problems, we propose UX (UDDI eXtension), a system that facilitates requesters to discover services with good performance. In each enterprise domain, the requesters’ QoS feedback is received and then stored in a local UX server. By sharing these experiences from all the requesters in the local domain, the system can predict the service’s future performance. To support the discovery between different cooperation domains, we design a general federated service and then enhance the UX system’s federated discovery ability based on this federated service. The system handles the federated inquiry and provides a simple view over the whole federation. Meanwhile the UX server’s inquiry interface will still conform to the UDDI Specification.
AOP for Dynamic Configuration and Management of Web Services
Authors: Verheecke Bart , Cibran María Agustina , Vanderperren Wim , Suvee Davy , Jonckers Viviane
Published: February 2011

We observe that current approaches for the integration of Web services hard-wire the service references into client applications, affecting adaptability and reusability. Moreover, support for client-side management is hardly provided. To enable the development of more flexible and robust applications we propose the Web Services Management Layer (WSML). In this article we identify the requirements for the WSML to realize dynamic integration, client-side service management, and support for service criteria to govern the selection, integration and composition of Web services. We show how dynamic AOP, and in particular the dynamic aspect-oriented language JAsCo, is ideally suited to implement the core functionality of the WSML.
The Design of QoS Broker Algorithms for QoS-Capable Web Services
Authors: Yu Tao , Lin Kwei-Jay
Published: February 2011

QoS (quality of service) support in Web services is an important issue since it ensures service usability and utility for each client and, in addition, improves server utilization. In this article, we present a QoS-capable Web service architecture, QCWS, by introducing a QoS broker module between service clients and providers (servers). The functions of the QoS broker module include tracking QoS information about servers, making selection decisions for clients, and negotiating with servers to get QoS agreements. We study two resource allocation algorithms (HQ and RQ) used by QoS brokers acting as the front-end of servers. The goals of the algorithms are to maximize the server resource usage while minimizing the QoS instability for each client. The first algorithm, HQ, assigns a homogeneous service level to all clients on the system and adjusts the service level according to the number of active clients. The second algorithm, RQ, assigns different service levels to clients according to their needs. Both algorithms try to minimize the resource reallocations for existing clients. The QoS performance and instability trade-offs are studied by simulation.
A Preliminary Study of Suppressing Redundant Nested Invocations from a Web Service with Active Replication
Authors: Fang Chen-Liang , Liang Deron , Chen Chyouhwa , Lin PuSan
Published: February 2011

Zwass (1996) suggested that middleware and message service is one of the five fundamental technologies used to realize electronic commerce (EC). The Simple Object Access Protocol (SOAP) is recognized as a more promising middleware for EC applications among other leading candidates such as CORBA. We notice that the fault-tolerance issue is somewhat neglected in the current standard, that is, SOAP 1.1. We therefore proposed a fault tolerant Web service called fault-tolerant SOAP or FT-SOAP through which Web services can be built with higher resilience to failure. Active replication is a common approach to building highly available and reliable distributed software applications. The redundant nested invocation (RNI) problem arises when servers in a replicated group issue nested invocations to other server groups in response to a client invocation. In this work, we propose a mechanism to perform auto-suppression of redundant nested invocation in an active replication FT-SOAP system. Our approach ensures the portability requirement of a middleware, especially for FT-SOAP. The current design of the suppression mechanism itself does not consider the fault-tolerance issue. In other words, it suffers from the single-point of failure. Furthermore, the preliminary performance results indicates significant performance penalty due to inefficient SOAP invocations. More comprehensive experiments are needed to further investigate the feasibility of the current approach in the context of system performance.
Web Services Discovery with DAML-QoS Ontology
Authors: Zhou Chen , Chia Liang-Tien , Lee Bu-Sung
Published: February 2011

As more and more Web services are deployed, Web service’s discovery mechanisms become essential. Similar services from different sources often exhibit quite different Quality of Service (QoS) levels. For service selection and management purpose, it is necessary to explicitly, precisely, and flexibly specify various constraints and QoS metrics for Web services descriptions. This paper provides a novel ontology as a complement to DARPA Agent Markup Language—Service (DAML-S) Ontology to provide a better QoS metrics model. Three layers are defined, together with clear role descriptions for development. Cardinality constraints are utilized to describe the QoS property constraints. A matchmaking algorithm with multiple matching degrees is provided accordingly. When incorporated with DAML-S, the multiple service level objectives can be described by assigning multiple QoS profiles to one service profile. A prototype system was developed, which demonstrates the feasibility for small to medium-sized service advertisement repository.
Ontology and Service Oriented Programming
Authors: Li Bing , Tsai Wei-Tek
Published: February 2011

This paper presents a novel methodology to develop and integrate distributed applications. It starts from analyzing requirement specifications based on a service’s point of view. Thereafter, it is required to describe each service using ontology. The modeling and describing procedures are regarded as a new way to program Ontology and Service Oriented (OSO) programming, and descriptions obtained in the procedure are called OSO code. Moreover, OSO code has the features of interpretability, transformability, comparability, composability, and portability. Those features support code interpretation and generation. In addition, OSO code is also human-readable. This feature minimizes development efforts. Finally, since business logic in OSO code is represented in a machine-understandable format, the procedure of business process integration is completed automatically, based on business logic understanding.
NAM
Authors: Ghandeharizadeh Shahram , Papadopoulos Christos , Cai Min , Zhou Runfang , Pol Parikshit
Published: February 2011

Web Services is an emerging software technology that is based on the concept of software and data as a service. Binary and XML are two popular encoding/decoding mechanisms for network messages. A Web Service may employ a loss-less compression technique (e.g., Zip, XMill, etc.) in order to reduce message size prior to its transmission across the network, minimizing its transmission time. This saving might be outweighed by the overhead of compressing the output of a Web Service at a server and decompressing it at a client. The primary contribution of this paper is NAM, a middleware that strikes a compromise between these two factors in order to enhance response time. NAM decides when to compress data, based on the available client and server processor speeds and network characteristics. When compared with today’s common practice to transmit the output of a Web Service uncompressed always, our experimental results show NAM either provides similar or significantly improved response times (at times, more than 90% improvement) with Internet connections that offer bandwidths ranging from 80 to 100 Mbps.
Bandwidth and Latency Considerations for Efficient SOAP Messaging
Authors: Werner Christian , Buschmann Carsten , Jacker Tobias , Fischer Stefan
Published: February 2011

Although Web service technology is being used in more and more distributed systems, its areas of application are inherently limited by high latencies and high amounts of protocol overhead. For messaging in environments with user interaction, like Web platforms for business or multimedia applications, the response time of the whole system needs to be kept in tight boundaries. In other scenarios including mobile communication and battery-powered devices, bandwidth-efficient communication is imperative. In this paper, we address both of these issues. First we conduct a detailed latency analysis of different transport mechanisms for SOAP and then we thoroughly investigate their protocol overhead. For both aspects we present a theoretical analysis as well as experimental measurement results. We then will introduce a new transport binding called PURE that significantly reduces the protocol overhead while featuring low latency. Furthermore it enables interesting additional features such as point-to-multipoint communication via IP multicast and broadcast.
XML Data Services
Authors: Borkar Vinayak , Carey Michael , Mangtani Nitin , McKinney Denny , Patel Rahul , Thatte Sachin
Published: February 2011

In this paper, we address the question, “In the brave new world of Web services and service-oriented architectures (SOA), how does data fit in?” We bring data modeling concepts to bear on the world of services, yielding an approach in which enterprise data access is handled by a collection of interrelated data services. We show how the approach can be realized on a foundation of XML standards, namely XML Schema, Web services, and XQuery. We show that this approach provides a uniform and declarative framework for integrating enterprise data assets that are drawn from disparate underlying sources, including both queryable and non-queryable data sources as well as data that is encapsulated by Web services. We also explain how the approach yields data services that are easily and efficiently reusable.
Search Strategies for Automatic Web Service Composition
Authors: Milanovic Nikola , Malek Miroslaw
Published: February 2011

This paper investigates architectural properties required for supporting automatic service composition. First, composable service architecture will be described, based on modeling Webn Services as abstract machines supported by formally defined composition operators. Based on the proposed infrastructure, we give several options for achieving automatic service composition by treating it as a search problem. Namely, basic heuristic, probabilistic, learning-based, decomposition and bidirectional automatic composition mechanisms will be presented and compared. Finally, it discusses the impact and outlook for automatic composition.
An Adaptive Access Control Model for Web Services
Authors: Bertino Elisa , Squicciarini Anna C. , Martino Lorenzo , Paci Federica
Published: February 2011

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.
A Dynamic Two-Phase Commit Protocol for Adaptive Composite Services
Authors: Yu Weihai , Pu Calton
Published: February 2011

Next-generation applications based on Web services impose additional requirements on the use of coordination protocols with various optimizations, such as the two-phase commit protocol (2PC). This article analyses the well-known 2PC optimizations “presumed commit” and “presumed abort,” and presents an improved 2PC that is suitable for Web-service-based applications. More specifically, the protocol allows every individual service provider to choose dynamically the most appropriate presumption for any distributed transaction. This new capability is especially useful when a composite Web service is integrating component services that make different presumptions in their commit protocols. The protocol does not introduce extra overhead to the previous 2PC variants in terms of number of messages and log records, and it is easy to understand and realize. Our simulation shows that the choice of appropriate presumption has significant influence on system performance, and that in some heterogeneous settings, combining different presumptions in individual transactions outperforms adopting only one single presumption.
A Metamorphic Testing Approach for Online Testing of Service-Oriented Software Applications
Authors: Chan W. K. , Cheung S. C. , Leung Karl R.P.H.
Published: February 2011

Testing the correctness of services assures the functional quality of service-oriented applica-tions. A service-oriented application may bind dynamically to its supportive services. For the same service interface, the supportive services may behave differently. A service may also need to realize a business strategy, like best pricing, relative to the behavior of its counterparts and the dynamic market situations. Many existing works ignore these issues to address the problem of identifying failures from test results. This article proposes a metamorphic approach for online services testing. The off-line testing determines a set of successful test cases to construct their corresponding follow-up test cases for the online testing. These test cases will be executed by metamorphic services that encapsulate the services under test as well as the implementations of metamorphic relations. Thus, any failure revealed by the metamorphic testing approach will be due to the failures in the online testing mode. An experiment is included.
Dealing with Scale and Adaptation of Global Web Services Management
Authors: Vambenepe William , Thompson Carol , Talwar Vanish , Rafaeli Sandro , Murray Bryan , Milojicic Dejan , Iyer Subu , Farkas Keith I. , Arlitt Martin
Published: February 2011

Service Oriented Architectures (SOA) are becoming the prevalent approach for realizing modern services and systems. SOA offers superior support for autonomy (decoupling) and heterogeneity compared to previous generation middleware systems, resulting in more scalable and adaptive solutions. However, SOA have not adequately addressed management, while traditional management solutions do not sufficiently scale to address the needs of (global) Web services. We propose scalable management based on models and industry standards. We discuss a use case for global service management and present its design, implementation, and preliminary evaluation. We retain all the benefits of SOA while also enabling global scale manageability. Our approach provides manageability that is comprehensible for administrators yet automated enough for integration into autonomous systems.
Ontology Driven Data Mediation in Web Services
Authors: Nagarajan Meenakshi , Verma Kunal , Sheth Amit P. , Miller John A.
Published: February 2011

With the rising popularity of Web services, both academia and industry have invested considerably in Web service description standards, discovery, and composition techniques. The standards-based approach utilized by Web services has supported interoperability at the syntax level. However, issues of structural and semantic heterogeneity between messages exchanged by Web services are far more complex and crucial to interoperability. It is for these reasons that we recognize the value that schema/data mappings bring to Web service descriptions. In this article, we examine challenges to interoperability; classify the types of heterogeneities that can occur between interacting services, and present a possible solution for data interoperability using the mapping support provided by WSDL-S, a key driver behind SAWSDL. We present a data mediation architecture using the extensibility features of WSDL and the popular SOAP engine, Axis 2.
Business Process Control-Flow Complexity
Authors: Cardoso Jorge
Published: February 2011

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.
An Access-Control Framework for WS-BPEL
Authors: Paci Frederica , Bertino Elisa , Crampton Jason
Published: February 2011

Business processes, the next-generation workflows, have attracted considerable research interest in the last 15 years. More recently, several XML-based languages have been proposed for specifying and orchestrating business processes, resulting in the WS-BPEL language. Even if WS-BPEL has been developed to specify automated business processes that orchestrate activities of multiple Web services, there are many applications and situations requiring that people be considered as additional participants who can influence the execution of a process. Significant omissions from WS-BPEL are the specification of activities that require interactions with humans to be completed, called human activities, and the specification of authorization information associating users with human activities in a WS-BPEL business process and authorization constraints, such as separation of duty, on the execution of human activities. In this article, we address these deficiencies by introducing a new type of WS-BPEL activity to model human activities and by developing RBAC-WS-BPEL, a role-based access-control model for WS-BPEL, and BPCL, a language to specify authorization constraints.
Communication Web Services and JAIN-SLEE Integration Challenges
Authors: Falcarin Paolo , Venezia Claudio
Published: February 2011

Meshing up telecommunication and IT resources seems to be the real challenge for supporting the evolution towards the next generation of Web Services. In telecom world, JAIN-SLEE (JAIN Service Logic Execution Environment) is an emerging standard specification for Java service platforms targeted to host value added services, composed of telecom and IT services.In this paper we describe StarSLEE platform which extends JAIN-SLEE in order to compose JAIN-SLEE services with Web services and the StarSCE service creation environment which allows exporting value added services as communication web services, and we analyze open issues that must be addressed to introduce Web Services in new telecom service platforms.
Interoperability Among Heterogeneous Services
Authors: Tsalgatidou Aphrodite , Athanasopoulos George , Pantazoglou Michael
Published: February 2011

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.
Perceived Effectiveness of E-Government and its Usage in City Governments
Authors: Reddick Christopher G.
Published: February 2011

This article examines the perceived effectiveness of e-government by Information Technology (IT) directors in local governments in the United States. Most of the existing empirical research has examined the level of adoption of e-government; it does not focus on what is the overall effectiveness of e-government for city governments as this study does. This is accomplished through a survey of IT directors exploring their perceptions of e-government to determine whether this is related to the overall usage of e-government in cities. Websites were the most effective service channel for getting information; the telephone was the most effective service channel for solving a problem; while in person at a government office was most effective service channel for citizens’ to access city services. E-government usage was positively related to managerial effectiveness, having a champion of e-government, and perceived effectiveness of citizen access to online information.
High Performance Approach for Server Side SOAP Processing
Authors: Li Lei , Niu Chunlei , Chen Ningjiang , Wei Jun , Huang Tao
Published: February 2011

Based on XML, Web services inherit not only the advantages of XML, but its relatively poor performance, which makes it a poor choice for many high-performance applications. In this paper, we propose a new approach to improve Web services performance. Focusing on avoiding traditional XML parsing and Java reflection at runtime, this paper develops a service-specific SOAP Processor to accelerate execution. Moreover, SOAP Processor embeds several cache implementations and uses a novel adaptive cache mechanism, which can choose an optimized cache implementation dynamically in the runtime. Through our experiments in this paper, we observed that our approach can achieve a huge performance gain by incorporating the SOAP Processor into the SOAP engine.
Selective Service Provenance in the VRESCo Runtime
Authors: Michlmayr Anton , Rosenberg Florian , Leitner Philipp , Dustdar Schahram
Published: February 2011

In general, provenance describes the origin and well-documented history of a given object. This notion has been applied in information systems, mainly to provide data provenance of scientific workflows. Similar to this, provenance in Service-oriented Computing has also focused on data provenance. However, the authors argue that in service-centric systems the origin and history of services is equally important. This paper presents an approach that addresses service provenance. The authors show how service provenance information can be collected and retrieved, and how security mechanisms guarantee integrity and access to this information, while also providing user-specific views on provenance. Finally, the paper gives a performance evaluation of the authors’ approach, which has been integrated into the VRESCo Web service runtime environment.