We investigate the problem of establishing trust in service-oriented environments. We focus on providing a reputation framework that would enable trust-based interactions with and amongst Web services. We define methods for the creation of reputation information, its collection, and assessment that are robust in the face of a variety of attacks. Our framework (denoted RATEWeb) supports a cooperative model in which Web services share their experiences of the service providers with their peers through feedback ratings. The different ratings are aggregated to derive a service provider's reputation. This in turn is used to evaluate trust. For situations where rater feedbacks are scarce, we use statistical forecasting (particularly, a Hidden Markov Model) to ascertain trust. The approaches and techniques developed under the RATEWeb framework facilitate the optimal selection and/or composition of Web services based on service reputations. We conduct an extensive performance study (analytical and experimental) to assess the fairness and accuracy of the proposed techniques. / Ph. D.

Since the early 2000s, Service Oriented Architectures (SOAs) have played a key role in the development of complex applications within a virtual organization (VO) context. Grids and workflows have emerged as vital technologies for addressing the (SOA) paradigm. Given the variety of Grid middleware, scientific workflow systems and Grid workflows available, bringing the two technologies together in a flexible, reusable and generalized way has been largely overlooked, particularly from a scientific end user perspective. The lack of domain focus in this area has led to a slow uptake of Grid technologies. This thesis aims to design a framework for Grid-enabling workflows, which identifies the essential technological components, how these components fit together in layered architecture and the interactions between them. To produce such a framework, this thesis first investigates the definition of a Grid-workflow architecture and mapping Grid functionality to workflow nodes, focusing on striking a balance between performance, usability and the Grid functionality supported. Next, it presents an examination of framework extensions for supporting various forms of Grid heterogeneity, essential for ii VO based collaboration. Given the complex nature of Grid technologies, the work presented here investigates abstracting Grid based workflows through high-level definitions and resolution using semantic technologies. Finally, this thesis presents a way to resolves abstract Grid workflows using semantic technologies and intelligent, autonomous agents. The frameworks presented in this thesis are tested and evaluated within the context of domain-based case studies defined in the SIMDAT, BRIDGE and ARGUGRID EU funded research projects.

Das Gebiet der Serviceentwicklung im Rahmen serviceorientierter Architekturen, als auch der Bereich der Geschäfts­prozessmodellierung gewannen in den letzten Jahren zunehmend an Bedeutung. Aus fachlicher Sicht stellt die Analyse, Simulation und Optimierung aktueller und zukünftiger Geschäftsprozesse ein wertvolles Instrument zur Erkennung von Schwachstellen und der Verbesserung der Leistungsfähigkeit von Unternehmen dar. Aus IT-Sicht bietet die Service­orientierung die Möglichkeit, Unternehmensressourcen über öffentliche und private Schnittstellen verfügbar, und damit die Position des Unternehmens im Netzwerk von Lieferanten, Kunden und Geschäfts­partnern zu stärken. Den Kern dieser Arbeit bildet die Untersuchung des Spannungsfeldes zwischen fachlicher Geschäfts­­­prozess- und Servicemodellierung, sowie der Ausführung von Geschäftsprozessen auf techni­scher Ebene, die durch Services unterstützt werden. Im Fokus der Betrachtung liegt der unter­nehmens- bzw. organisations­übergreifende Bereich, insbesondere der Finanzdienst­leistungs­sektor. Zu Beginn der Arbeit wird ein allgemeines Begriffsverständnis zu Bereichen Service- und Prozess­modellierung geschaffen, die im Hauptteil der Arbeit verfeinert und ergänzt werden, um die Beson­der­heiten und Problemfelder für den überbetrieblichen Bereich verständlich zu machen. Dabei wird das RosettaNet-Frame­work als Rahmenwerk zur Gestaltung von elektronischen Geschäfts­prozessen beschrieben und im letzten Teil der Arbeit zur Implementierung eines konkreten Geschäfts­­prozesses im Vertriebsprozess heran­gezogen. Zu diesem Zweck wird der ORACLE WebLogic Application Server verwendet.

In this research, we propose a knowledge management architecture in a collaborative environment and service oriented organization. The architecture contains five components, including partners, knowledge bases, portals, pipes, and cloud. Each segment of knowledge which is created in partners’ portals will be displayed in the cloud. The cloud contains knowledge from portals. Portals and the cloud will be linked by a specific type of connections (pipes), which presents the knowledge to the cloud without copying them. We implement the proposed architecture online to prove its validity. The prototype that we examine has three partners including finance, insurance, and transportation. Each partner creates knowledge by using its portal and saving it in its own knowledge base (KB). Likewise, each partner has an access to other partners’ portals to ask questions or perform inquiries. The answered questions are saved in the KBs and displayed in the cloud. For implementation, we use Joomla as CMS portals, K2 as KB in each portal, Yahoo Pipes as connections between the portals and the cloud. Finally, the cloud is a webpage that displays knowledge from different portals. We demonstrate that the proposed architecture facilitates sharing knowledge among the partners in the VO, and prevents knowledge duplications in different KBs. Moreover, we could move the stored knowledge from KB to another by using backup feature the CMS portal if any partner want to leave or the VO decides to terminate.

Since the early 2000s, Service Oriented Architectures (SOAs) have played a key role in the development of complex applications within a virtual organization (VO) context. Grids and workflows have emerged as vital technologies for addressing the (SOA) paradigm. Given the variety of Grid middleware, scientific workflow systems and Grid workflows available, bringing the two technologies together in a flexible, reusable and generalized way has been largely overlooked, particularly from a scientific end user perspective. The lack of domain focus in this area has led to a slow uptake of Grid technologies. This thesis aims to design a framework for Grid-enabling workflows, which identifies the essential technological components, how these components fit together in layered architecture and the interactions between them. To produce such a framework, this thesis first investigates the definition of a Grid-workflow architecture and mapping Grid functionality to workflow nodes, focusing on striking a balance between performance, usability and the Grid functionality supported. Next, it presents an examination of framework extensions for supporting various forms of Grid heterogeneity, essential for ii VO based collaboration. Given the complex nature of Grid technologies, the work presented here investigates abstracting Grid based workflows through high-level definitions and resolution using semantic technologies. Finally, this thesis presents a way to resolves abstract Grid workflows using semantic technologies and intelligent, autonomous agents. The frameworks presented in this thesis are tested and evaluated within the context of domain-based case studies defined in the SIMDAT, BRIDGE and ARGUGRID EU funded research projects.

Although service oriented architecture has reached a particular maturity level especially in the technological dimension, there is a lack of common and acceptable approach to design a software system through composition and integration of web services. In this thesis, a service oriented system design approach for Service Oriented Architecture based software development is introduced to fill this gap. This new methodology basically offers a procedural top-down decomposition of a given software system allowing several abstraction levels. At the higher levels of the decomposition, the system is divided into abstract nodes that correspond to process models in the decomposition tree. Any node is a process and keeps the sequence and the state information for the possible sub-processes in this decomposition tree. Nodes which are defined as process models may include some sub-nodes to present details for the intermediate levels of the model. Eventually at the leaf level, process models are decomposed into existing web services as the atomic units of system execution. All processes constructing the system decomposition tree are modeled with BPEL (Business Process Execution Language) to expose the algorithmic details of the design. This modeling technique is also supported with a graphical modeling language referred to as SOSEML (Service Oriented Software Engineering Modeling Language) that is also newly introduced in this thesis.

Enterprises can be empowered to live up to the potential of becoming dynamic, agile and real-time. Service orientation is emerging from the amalgamation of a number of key business, technology and cultural developments. Three essential trends in particular are coming together to create a new revolutionary breed of enterprise, the service-oriented enterprise (SOE): (1) the continuous performance management of the enterprise; (2) the emergence of business process management; and (3) advances in the standards-based service-oriented infrastructures. This thesis focuses on this emerging three-layered architecture that builds on a service-oriented architecture framework, with a process layer that brings technology and business together, and a corporate performance layer that continually monitors and improves the performance indicators of global enterprises provides a novel framework for the business context in which to apply the important technical idea of service orientation and moves it from being an interesting tool for engineers to a vehicle for business managers to fundamentally improve their businesses.

Today’s market competitiveness and globalisation are putting pressure on organisations to join their efforts, to focus more on cooperation and interaction and to add value to their businesses. That is, most information systems supporting these cross-organisations are characterised as service-oriented business applications, where all the emphasis is put on inter-service interactions rather than intra-service computations. Unfortunately for the development of such inter-organisational service-oriented business systems, current service technology proposes only ad-hoc, manual and static standard web-service languages such as WSDL, BPEL and WS-CDL [3, 7]. The main objective of the work reported in this thesis is thus to leverage the development of service-oriented business applications towards more reliability and dynamic adaptability, placing emphasis on the use of business rules to govern activities, while composing services. The best available software-engineering techniques for adaptability, mainly aspect-oriented mechanisms, are also to be integrated with advanced formal techniques. More specifically, the proposed approach consists of the following incremental steps. First, it models any business activity behaviour governing any service-oriented business process as Event-Condition-Action (ECA) rules. Then such informal rules are made more interaction-centric, using adapted architectural connectors. Third, still at the conceptual-level, with the aim of adapting such ECA-driven connectors, this approach borrows aspect-oriented ideas and mechanisms, and proposes to intercept events, select the properties required for interacting entities, explicitly and separately execute such ECA-driven behavioural interactions and finally dynamically weave the results into the entities involved. To ensure compliance and to preserve the implementation of this architectural conceptualisation, the work adopts the Maude language as an executable operational formalisation. For that purpose, Maude is first endowed with the notions of components and interfaces. Further, the concept of ECA-driven behavioural interactions are specified and implemented as aspects. Finally, capitalising on Maude reflection, the thesis demonstrates how to weave such interaction executions into associated services.

Service-oriented architecture (SOA) governance has been identified as the most important factor affecting the outcome of SOA within organisations. However, authors have failed to explain how organisations should govern specific aspects of its SOA, leaving a gap in the literature. Therefore, the purpose of this study was to investigate established SOA governance mechanisms in order to explain implications of governance in a SOA context. The research question of the study was to identify which SOA governance mechanisms do or do not provide support for different constituents of SOA. The study also contained three sub-questions; (i) Is there a difference between how SOA governance mechanisms support technical vs. non technical constituents of SOA? (ii) Is there any SOA governance mechanism that is more important than others? (iii) Is there a relation between the SOA governance mechanisms?   The study was conducted using theories related to SOA and SOA governance. We identified the most academically accepted SOA governance mechanisms to test their support for different constituents of SOA. To get an holistic view of SOA, we used a SOA maturity framework to identify what the constituents of SOA really are. The support of the SOA governance mechanisms were then studied in relation to the different constituents of SOA, through interviews and observations, during a ten week internship at Scania.   The results showed that as good as every SOA governance mechanism supports the constituents of SOA, although the level of support varied. In general, we found patterns separating the support for technological and non-technological constituents of SOA. The technological constituents of SOA were to a great extent provided the same support from SOA governance mechanisms, which also was true for the non-technological constituents of SOA. Interestingly, except for one SOA governance mechanism, the technological constituents of SOA and the non-technological obtained different levels of support from governance. The most important SOA governance mechanisms are the creation of standards and policies, having processes to create and enforce policies, processes for education, and establishing SOA skills and training. We can also conclude that there is a relationship between many of the SOA governance mechanisms, and that academics and practitioners therefore have to view SOA governance holistically, rather than independent governance mechanisms.

Service Oriented Architecture (SOA) is an increasingly important software architecture, designed to flexibly connect separate components in response to rapid changes in the business environment. SOA focuses on the exchange of information between independent software components and on the reusability of the components by separating communication interface from internal implementation. There are several features of SOA that make legacy system modernization to SOA appealing in today’s world. These are loose coupling, abstraction of underlying logic, agility, flexibility, reusability, autonomy, statelessness, discoverability and reduced cost. Migration of legacy systems to SOA is an important problem. While migration of legacy data processing systems has been widely studied, migration of legacy web applications has not. In this thesis we review existing strategies for migration of monolithic legacy web applications to web services, noting the unique challenges due to the highly dynamic nature of the systems, poorly structured code, and weakly typed languages in web applications, and the need for automation to assist in the process. We present a new semi-automated framework for the analysis and migration of monolithic web applications to web services using source analysis and transformation techniques, and outline a set of source transformation steps that can be used to migrate existing legacy web applications to web services form. We demonstrate our framework on the analysis and automated restructuring of two large existing web applications to extract and migrate integrated internal features to independent, reusable web services. / Thesis (Ph.D, Computing) -- Queen's University, 2013-03-28 14:23:24.797