Vijay Machiraju

Bio: Vijay Machiraju is an academic researcher from Hewlett-Packard. The author has contributed to research in topics: Web service & WS-Policy. The author has an hindex of 22, co-authored 54 publications receiving 3850 citations.

Web Services: Concepts, Architectures and Applications

Abstract: Like many other incipient technologies, Web services are still surrounded by a substantial level of noise. This noise results from the always dangerous combination of wishful thinking on the part of research and industry and of a lack of clear understanding of how Web services came to be. On the one hand, multiple contradictory interpretations are created by the many attempts to realign existing technology and strategies with Web services. On the other hand, the emphasis on what could be done with Web services in the future often makes us lose track of what can be really done with Web services today and in the short term. These factors make it extremely difficult to get a coherent picture of what Web services are, what they contribute, and where they will be applied.Alonso and his co-authors deliberately take a step back. Based on their academic and industrial experience with middleware and enterprise application integration systems, they describe the fundamental concepts behind the notion of Web services and present them as the natural evolution of conventional middleware, necessary to meet the challenges of the Web and of B2B application integration. Rather than providing a reference guide or a "how to write your first Web service" kind of book, they discuss the main objectives of Web services, the challenges that must be faced to achieve them, and the opportunities that this novel technology provides. Established, as well as recently proposed, standards and techniques (e.g., WSDL, UDDI, SOAP, WS-Coordination, WS-Transactions, and BPEL), are then examined in the context of this discussion in order to emphasize their scope, benefits, and shortcomings. Thus, the book is ideally suited both for professionals considering the development of application integration solutions and for research and students interesting in understanding and contributing to the evolution of enterprise application technologies.

Automated SLA Monitoring for Web Services

Abstract: SLA monitoring is difficult to automate as it would need precise and unambiguous specification and a customizable engine that collects the right measurement, models the data and evaluates the SLA at certain times or when certain events happen Also most of the SLA neglect client side measurement or restrict SLAs to measurements based only on server side In a cross-enterprise scenario like web services it will be important to obtain measurements at multiple sites and to guarantee SLAs on them In this article we propose an automated and distributed SLA monitoring engine

Towards Automated SLA Management for Web Services

Abstract: In order to automate SLA management it is essential to specify SLAs in precise and unambiguous manner as well as keep the specification flexible. While precision will help automate the process of monitoring and metric collection, flexibility will enable extending it to unforeseen service level agreement specifications.

Automated provisioning of virtual machines for a virtual machine buffer pool and production pool

Abstract: An automated provisioning system provisions computing resources for shared services in a resource-on-demand system. A number of virtual machines needed for a virtual machine production pool for a period of time to satisfy the computing demand for the shared services is determined from a policy. Also, a number of unassigned virtual machines needed for a virtual machine buffer pool is determined from the policy. Servers and virtual machines are automatically provisioned for the virtual machine production pool and the virtual machine buffer pool based on the determined number of virtual machines needed for the virtual machine production pool, the determined number of unassigned virtual machines needed for the virtual machine buffer pool, and a changing computing demand of the shared services during the period of time.

Specifying and monitoring guarantees in commercial grids through SLA

Abstract: Grid computing has relied on "best effort" as the guiding principal of operation. However, commercial grids need to provide much stricter guarantees. These guarantees have to be specified in terms of service level agreements and have to be monitored and assured. We propose an architecture for specifying and monitoring service level agreements to achieve the above. The architecture relies on a network of communicating proxies each maintaining SLAB committed within the administrative domain of the proxy. SLAB are either negotiated between or specified to management proxies, and they are responsible for automated monitoring of data and for triggering evaluations of the registered SLAs. An unambiguous and,flexible language for formalizing SLAB is presented to achieve the above. The management proxy allows reasoning about the overall status of SLAB related to an application context across multiple administrative domains by contacting and querying involved management proxies, obtaining measurement information from multiple proxies, if needed and performing a consolidated SLA evaluation. The process of measurement collection, and SLA evaluation is automated and based on web services technology. The scenario considers HP Utility Data Center as a typical Commercial Grid deployment environment.

Service oriented architectures: approaches, technologies and research issues

Abstract: Service-oriented architectures (SOA) is an emerging approach that addresses the requirements of loosely coupled, standards-based, and protocol- independent distributed computing. Typically business operations running in an SOA comprise a number of invocations of these different components, often in an event-driven or asynchronous fashion that reflects the underlying business process needs. To build an SOA a highly distributable communications and integration backbone is required. This functionality is provided by the Enterprise Service Bus (ESB) that is an integration platform that utilizes Web services standards to support a wide variety of communications patterns over multiple transport protocols and deliver value-added capabilities for SOA applications. This paper reviews technologies and approaches that unify the principles and concepts of SOA with those of event-based programing. The paper also focuses on the ESB and describes a range of functions that are designed to offer a manageable, standards-based SOA backbone that extends middleware functionality throughout by connecting heterogeneous components and systems and offers integration services. Finally, the paper proposes an approach to extend the conventional SOA to cater for essential ESB requirements that include capabilities such as service orchestration, "intelligent" routing, provisioning, integrity and security of message as well as service management. The layers in this extended SOA, in short xSOA, are used to classify research issues and current research activities.

Web Service Modeling Ontology

Abstract: The potential to achieve dynamic, scalable and cost-effective marketplaces and eCommerce solutions has driven recent research efforts towards so-called Semantic Web Services that are enriching Web services with machine-processable semantics. To this end, the Web Service Modeling Ontology (WSMO) provides the conceptual underpinning and a formal language for semantically describing all relevant aspects of Web services in order to facilitate the automatization of discovering, combining and invoking electronic services over the Web. In this paper we describe the overall structure of WSMO by its four main elements: ontologies, which provide the terminology used by other WSMO elements, Web services, which provide access to services that, in turn, provide some value in some domain, goals that represent user desires, and mediators, which deal with interoperability problems between different WSMO elements. Along with introducing the main elements of WSMO, we provide a logical language for defining formal statements in WSMO together with some motivating examples from practical use cases which shall demonstrate the benefits of Semantic Web Services.

Taverna: a tool for building and running workflows of services

Abstract: Taverna is an application that eases the use and integration of the growing number of molecular biology tools and databases available on the web, especially web services. It allows bioinformaticians to construct workflows or pipelines of services to perform a range of different analyses, such as sequence analysis and genome annotation. These high-level workflows can integrate many different resources into a single analysis. Taverna is available freely under the terms of the GNU Lesser General Public License (LGPL) from http://taverna.sourceforge.net/.

Restful web services vs. "big"' web services: making the right architectural decision

Abstract: Recent technology trends in the Web Services (WS) domain indicate that a solution eliminating the presumed complexity of the WS-* standards may be in sight: advocates of REpresentational State Transfer (REST) have come to believe that their ideas explaining why the World Wide Web works are just as applicable to solve enterprise application integration problems and to simplify the plumbing required to build service-oriented architectures. In this paper we objectify the WS-* vs. REST debate by giving a quantitative technical comparison based on architectural principles and decisions. We show that the two approaches differ in the number of architectural decisions that must be made and in the number of available alternatives. This discrepancy between freedom-from-choice and freedom-of-choice explains the complexity difference perceived. However, we also show that there are significant differences in the consequences of certain decisions in terms of resulting development and maintenance costs. Our comparison helps technical decision makers to assess the two integration styles and technologies more objectively and select the one that best fits their needs: REST is well suited for basic, ad hoc integration scenarios, WS-* is more flexible and addresses advanced quality of service requirements commonly occurring in enterprise computing.