An Architecture for providing and defining student-oriented services

A service-oriented architectural (SOA) model is proposed for power system reliability analysis especially for generating capacity adequacy evaluation. Generating system adequacy evaluation is performed to evaluate the ability of the system generating capacity to meet the total system demand. The proposed SOA model is composed of generation system reliability (GSR) service provider, power system service registry and service requester. The data pertaining to power system reliability analysis are represented in extensible markup language (XML) for exchanging the reliability data among the users and service providers. The GSR service provider describes the reliability evaluation services and publishes them to the power system service registry. The calling sequences of reliability evaluation services along with required data are configured as SOAP (Simple Object Access Protocol) messages and the proposed SOA model communicates between the service provider and the service requester with formally defined messages. The proposed model for generating system reliability analysis is highly distributed and has inherent features such as scalability and flexibility and provides a loosely coupled environment for power system reliability analysis.

Cloud computing is currently the most hyped and popular paradigm in the domain of distributed computing. Multiple vendors are providing infrastructure, platform, and software-related cloud products or solutions, and the number of such vendors is growing rapidly. But the reality is that there is very little in the form of standards in general and interoperability standards in particular. This leads to a challenging situation for cloud service consumers as they need to use solutions provided by multiple cloud vendors in order to fulfill their business requirements, and the lack of standardization leads to lack of interoperability among the solutions provided by varied vendors. Service brokers act as intermediaries between the cloud service providers and consumers. The role of service brokers becomes critical in situations that need integration among multiple systems as they bridge the interoperability gaps among multiple cloud solutions and thus compensate for the lack of standards. They do so by acting as agents adding value on behalf of the service consumers. The usage of such cloud brokers also helps to future-proof the solution as service brokers add a layer of indirection, thus enabling loose coupling among the cloud service consumers and providers. The aim of this chapter is to review the role of cloud service brokers in cloud computing. The review includes consolidation of the definitions and characteristics of cloud service brokers, review of the current brokerage solutions, and interfacing requirements. Also presented are a high-level cloud service broker functional architecture, criteria for selection of a cloud service broker, future trends and review of benefits, and challenges of using cloud service brokers.

Interorganisational new service development capability in the mobile communications ecosystem

Following September 11 2001, company ABC zeroed in on a home-grown fat client system, System E, as the enterprise data warehouse for risk management. It became mission critical for System E to remove key person dependencies and migrate from C++, a niche technology, to a more accessible platform. Under the leadership of a new hire, System E adopted an Service Oriented Architecture (SOA) approach to re-architecture. As company ABC’s IT unit is under a flat headcount constraint, an incremental SOA approach was the only way to get upper management approval. A pilot is well underway and scheduled to complete in December 2005. This paper presents the current/target architectures of System E, a theoretical framework for SOA, the Unified Modeling Language class diagram for SOA Model at ABC, and concludes with lessons learned from the pilot to date. Key contributions of the paper include SOA Model at ABC, and lessons learned regarding enterprise architecture initiatives.

The paper aims to analyze the possibilities of increasing the reliability level of software applications based on a Service Oriented Architecture (SOA) by the means of Design by Contract principles and explicit manipulation of business rules. Two architectural approaches have been taken into consideration: process centric SOA and information centric SOA. Also, a comparative analysis regarding the use of process diagrams versus use cases in SOA modeling is presented.

In this article we address the integration of functional models with non-functional models in the context of service-oriented enterprise architecture. Starting from the observation that current approaches to model-driven development have a strong focus on functionality, we argue the necessity of including non-functional aspects as early as possible in the service design process. We distinguish two modelling spaces, the design space and the analysis space, which can be integrated by means of model transformations. Quantitative results obtained in the analysis space, using special-purpose analysis techniques, can be related back to the design models by means of a reverse transformation. This provides a framework for incorporating non-functional analysis into methodological support for e-service development. While, for detailed design models, performance analysis is more or less covered by existing techniques, there is still a gap at the architectural overview level. Therefore, we propose an approach for performance analysis of layered, service-oriented architecture models, which consists of two phases: a ‘‘top-down’’ propagation of workload parameters, and a “bottom-up’’ propagation of performance or cost measures. By means of an example, we demonstrate the application of the approach and show that a seamless integration with detailed performance analysis methods (e.g., queueing analysis) can be achieved.

Service Oriented Computing (SOC) is a computing paradigm broadly pushed by vendors, utilizing services to support the rapid development of distributed applications in heterogeneous environments. The visionary promise of SOC is a world of cooperating services being loosely coupled to flexibly create dynamic business processes and agile applications that may span organizations and computing platforms and can nevertheless adapt quickly and autonomously to changes of requirements or context. Consequently, the subject of Service Oriented Computing is vast and enormously complex, spanning many concepts and technologies that find their origins in diverse disciplines like Workflow Management Systems, Component Based Computing, "classical" Web applications, and Enterprise Application Integration (EAI) including Message Oriented Middleware. In addition, there is a strong need to merge technology with an understanding of business processes and organizational structures, a combination of recognizing an enterprise's pain points and the potential solutions that can be applied to correct them. Middleware, on the other hand, is defined by the ObjectWeb consortium as the software layer in a distributed computing system that lies between the operating system and the applications on each site of the system. Middleware is the enabling technology of system and enterprise application integration (EAI) and therefore it clearly and evidently plays a key role for SOC. While the immediate need of middleware support for Service Oriented Architectures (SOA) is evident, current approaches and solutions mostly fall short by primarily providing support for the EAI aspect of SOC only and do not sufficiently address composition support, service management and monitoring. Moreover, quality properties (in particular dependability and security) need to be addressed not only by interfacing and communication standards, but also in terms of integrated middleware support. But what makes these issues so different in a SOA setting? Why - for instance - is traditional middleware support for transaction processing different to transaction processing in SOA, reflecting different types of atomicity needs? One answer lies in the administrative heterogeneity, the loose coupling between coarsegrained operations and long-running interactions, high dynamicity, and the required flexibility during run-time. Recently, massive-scale and mobility were added to the challenges for Middleware for SOC. However, loose coupling is not always the best approach to solve a particular problem. In order to temporarily allow for a stronger (traditional) form of coupling (like group membership agreement or atomic transaction), the middleware also has to provide explicit and configurable means to change between different strengths of coupling and various communication paradigms. This will enable servicebased applications to take the best from both worlds by dynamically adjusting the interactions between the composed services. The highly dynamic modularity and need for flexible integration of services (e.g. Web service implementations) may require new middleware architectures, protocols, and services. These considerations also lead to the question to what extent service-orientation at the middleware layer itself is beneficial (or not). Recently emerging "Middleware as service" offerings, from providers like Amazon or from the open source community, support this trend towards "infrastructure services" that can be purchased and consumed over the Internet. However, this model may not be suitable for all kinds of middleware functions, including those addressing dependability (availability, reliability, integrity, safety, maintainability). Providing end-to-end properties and addressing cross-cutting concerns in a crossorganizational SOA is a particular challenge and the limits and benefits thereof have still to be investigated.

Understanding Service-Oriented Architecture (SOA): A systematic literature review and directions for further investigation

Cloud computing has become popular in various application domains based on infrastructure, platform, and software as a service model. Rapid deployment, high scalability, on-demand, and (theoretically) infinite resources have driven the industry towards the wide adoption of cloud computing services. However, the difficulty of cross-provider resource allocation and seamless resource transition is a major concern for such services. Therefore, the segregated cloud market forces its clients to use provider-specific and pre-configured options for their required resources and services. Thus, the overall market, even with the presence of multiple cloud service providers, operates as a direct service from the providers to the clients, and with non-negotiable pricing strategies for the cloud services. In this article, we propose Bepari, a cost-driven model for opaque service platforms for cloud computing. Bepari acts as a negotiation-based approach to deliver composite cross-provider cloud-based services to the end-users. Bepari provides a detailed service-oriented architecture for multiple cloud service providers to provide cross-platform and composite services. Furthermore, Bepari delivers a detailed cost model and comparison between establishing a cloud service vs. an opaque cloud service. Our empirical framework allows a Bepari service provider to analyze the profit model and create a market niche accordingly. Simulation results are provided, which validate the efficiency of a negotiated pricing strategy in terms of maximized resource utilization and profits for cloud service providers and cost reduction for the cloud users.

Service-oriented computing is becoming a direction of computing technology. For realising the mission of service-oriented computing, service-oriented architecture has been proposed to facilitate the application development via discoverable services distributed on Internet. That brings out service-oriented modelling as a new technical area to provide modelling and analysis techniques of service-oriented applications. The paper proposes a framework for agent-based service-oriented modelling. It treats both the service providers and the service requesters as service agents. Domain ontology has been used to provide the sharable domain knowledge as well as terminology for allowing the agents to understand each others. A modelling process has also been illustrated with the model development of an online auction service.

A key indicator of today's global business system supported by service oriented architecture (SOA), is the reliability and uptime. This concern is crucial for e-commerce sites and mission-critical business applications. SOA modelling is used to implement the concept of digital business ecosystem (DBE). In computing environment of DBE a chain of components link business applications together, and the strength of this chain, in terms of reliability and performance, will determine the success or failure of the business. One way to make the chain stronger is to increase the reliability of all components involved, especially the critical components of the chain. In this paper, we address the reliability issue of digital ecosystem's transactions. The major contribution of this research is to propose a framework for reliable transactions in DE, via the analysis of the reliability for Web services computing.

The Service Oriented Architecture (SOA) concept facilitates building flexible services that can be deployed in distributed environment, and executed on different hardware and software platforms. On the other hand SOA paradigm rises many challenges in the area of Quality of Service and resources utilization. In the paper Resources Distribution Manager (RDM) that manages resources and service delivery in order to satisfy user requirements and service provider's needs is presented. Requests for services are distributed to selected virtualized instances of services or optionally new instances are created for handling the requests. The allocation decisions are based on the knowledge about the communication resources and the current load of computational resources which are dynamically monitored by special RDM module. The decision on the resources allocation is then compared with its utilization during service execution and causes changes in allocation strategy.

Cloud computing (CC) services can offer substantial cost-effective global operational and relationship benefits if the cooperation between logistics and CC services are resilient. Potential vulnerabilities to cooperation of CC and logistics service providers can occur with respect to vital factors such as security and trust. Extant studies have demonstrated CC benefits as well as few challenges associated with CC services application. However, no extant study has examined the inter-organisational benefits based on cooperative resilience between CC and logistics service providers in terms of both capability and trust vulnerability factors. This study examines the cooperative resilience of logistics and CC service providers based on innovation diffusion theory within a supply chain risk assessment framework. Using structural equation modelling techniques, we investigate the relationship between the vulnerability factor (trust), capability factor (security) and collaboration benefits (relationship and operational) offered by CC service providers based on 236 Chinese logistics service firms’ perceptions of CC adoption. The results indicate Chinese logistics companies perceive security impediments as a major factor affecting cooperative resilience between logistics service and CC service providers.

Developments in service oriented architecture (SOA) have taken us near to the once fictional dream of forming and running an online business, such commercial activity in which most or all of its commercial roles are outsourced to online services. The novel concept of cloud computing gives a understanding of SOA in which Information Technology assets are provided as services that are extra flexible, inexpensive and striking to commercial activities. In this paper, we concisely study developments in concept of cloud computing, and debate the advantages of using cloud services for commercial activities and trade-offs that they have to consider. Further we presented a layered architecture for online business, and then we presented a conceptual architecture for complete online business working atmosphere. Moreover, we discuss the prospects and research experiments that are ahead of us in realizing the technical components of this conceptual architecture. We conclude by giving the outlook and impact of cloud services on both large and small businesses.

Quality of service (QoS) is an important consideration in the dynamic service selection in the context of service oriented architectures. This paper extends previous work on QoS brokering for SOAs by designing, implementing, and experimentally evaluating a service selection QoS broker that maximizes a utility function for service consumers. Utility functions allow stakeholders to ascribe a value to the usefulness of a system as a function of several attributes such as response time, throughput, and availability. This work assumes that consumers of services provide to a QoS broker their utility functions and their cost constraints on the requested services. Service providers register with the broker by providing service demands for each of the resources used by the services provided and cost functions for each of the services. Consumers request services from the QoS broker, which selects a service provider that maximizes the consumer's utility function subject to its cost constraint. The QoS broker uses analytic queuing models to predict the QoS values of the various services that could be selected under varying workload conditions. The broker and services were implemented using a J2EE/Weblogic platform and experiments were conducted to evaluate the broker's efficacy. Results showed that the broker adequately adapts its selection of service providers according to cost constraints.