QUALITY OF SERVICE BASED WEB SERVICE SELECTION: AN EVALUATION OF TECHNIQUES

In service oriented computing, web services are the basic construct that aims to facilitate building of business application in a more flexible and interoperable manner for enterprise collaboration. One of the most promising advantages of web service technology is the possibility of creating added-value services by combining existing ones. A key step for composing and executing services lies in the selection of the individual services to use. Much attention has been devoted to appropriate selection of service functionalities, but also the non-functional properties of the services play a key role. A web service selection technique must take as much as possible the important influencing aspects into account to the selection processes in order to minimize the selection efforts. This paper evaluates several web service selection techniques published in literature with the focus on their contributions to web service selection. The evaluation results may be used as a basis for improving web service selection techniques that may simplify the selection tasks

Service oriented architecture (SOA) implementation framework for heterogeneous information systems integration

Heterogeneous information systems (IS) creates difficulties to automatically integrate data in different IS environment. These situations have increased operating and maintenance costs as well as wasteful data storage, which is caused by data redundancy. Since the emerging of Service Oriented Architecture (SOA), the latest trend in IS development, many researchers have proposed various SOA conceptual models and frameworks. The main objective behind these efforts was to provide a guideline for a successful SOA adoption. In Malaysia, higher learning institutions have taken some initiatives to implement SOA-based systems to improve the quality of IS performance. However, most of the existing SOA frameworks available are still lacking of good design to support an integration of heterogeneous IS. In order to fill this gap, this study was conducted to seek for an opportunity to enhance the existing SOA implementation frameworks of heterogeneous IS integration. A consolidation of the existing related frameworks and consensus from experts yield a new SOA framework. A case study approach in a Malaysia public university was applied to test and validate the framework by conducted prototyping experiments with the focus on several student information systems. The evaluation from the users shows that the proposed framework has met SOA criteria like service based, data update in real time and accessibility. This finding has been proven with successful prototype experiments. With the findings and results of this study, an enhancement of SOA implementation framework was fulfilled by focusing on integrating heterogeneous IS. This is a new contribution SOA domain in the context of heterogeneous IS integration in Malaysia public universities

Localización de Fallas dirigida por Taxonomía en Aplicaciones Orientadas a Servicios

El paradigma de computación orientada a servicios resulta de particular interés tanto para la industria cómo para la investigación debido a sus numerosos bene ficios. En particular sus propiedades de interoperabilidad y capacidad de generar componentes altamente desacoplados, permite generar software mediante la composición de servicios. Pese a ser altamente relevante detectar fallas en estos sistemas tanto cómo para incrementar la producción, contribuir a la verifi cación y facilitar el reemplazo de servicios en la composición, el área de localización de fallas ha sido poco explorada. En este contexto se plantea un enfoque de localización de fallas dirigido por una taxonomía especifica, que se vale del modelo arquitectónico para aumentar la expresividad de los resultados. El objetivo es brindar una guía que asista al usuario permitiendo reducir los tiempos de localización, aumentar la precisión e incrementar el conocimiento acerca de los diferentes tipos de fallas que pueden suceder en estos sistemas particulares, como lo corroboran los resultados experimentales llevados a cabo.Sociedad Argentina de Informática e Investigación Operativ

Biologically Inspired Self-Healing Software System Architecture

Self-healing capabilities have begun to emerge as an interesting and potentially valuable property of software systems. Self-healing characteristic enables software systems to continuously and dynamically monitor, diagnose, and adapt itself after a failures has occur in their components. Adding such characteristic into existing software systems is immensely useful and valuable for allowing them to recover from failures. However, developing such self-healing software systems is a significant challenge. The nature introduces to us unforeseen concepts in terms of presenting biological systems that have the ability to handle its abnormal conditions. Based on this observation, this thesis presents self healing architecture for software system based on one of the biological processes that have the ability to heal by itself (the wound-healing process). The self-healing architecture provides software systems the ability to handle anomalous conditions that appear among its components. The presented architecture is divided into to layers, functional and healing layer. In the functional layer, the components of the system provide its services without any disruptions. The component is considered as faulty component if it fails to provide its services. The healing layer aims to heal the faulty component and return it to the running system without the awareness of the user. The presented self-healing software system is formally described to prove its functionality. Set-theoretic and Finite State Machine (FSM) is introduced. A prototype for the presented architecture has been implemented using Java language. Java objects are considered as the system components. The modules of the healing layer in the selfhealing architecture have been implemented into Java classes. An object from the module class will be created to perform its task for the healing process. The thesis concludes with recommendations for future works in this area and enhancement of the presented architecture

Bringing Introspection into BlobSeer: Towards a Self-Adaptive Distributed Data Management System

International audienceIntrospection is the prerequisite of an autonomic behavior, the first step towards a performance improvement and a resource-usage optimization for large-scale distributed systems. In Grid environments, the task of observing the application behavior is assigned to monitoring systems. However, most of them are designed to provide general resource information and do not consider specific information for higher-level services. More precisely, in the context of data-intensive applications, a specific introspection layer is required to collect data about the usage of storage resources, about data access patterns, etc. This paper discusses the requirements for an introspection layer in a data-management system for large-scale distributed infrastructures. We focus on the case of BlobSeer, a large-scale distributed system for storing massive data. The paper explains why and how to enhance BlobSeer with introspective capabilities and proposes a three-layered architecture relying on the MonALISA monitoring framework. We illustrate the autonomic behavior of BlobSeer with a self-configuration component aiming to provide storage elasticity by dynamically scaling the number of data providers. Then we propose a preliminary approach for enabling self-protection for the BlobSeer system, through a malicious clients detection component. The introspective architecture has been evaluated on the Grid'5000 testbed, with experiments that prove the feasibility of generating relevant information related to the state and the behavior of the system

ACHIEVING AUTONOMIC SERVICE ORIENTED ARCHITECTURE USING CASE BASED REASONING

Service-Oriented Architecture (SOA) enables composition of large and complex computational units out of the available atomic services. However, implementation of SOA, for its dynamic nature, could bring about challenges in terms of service discovery, service interaction, service composition, robustness, etc. In the near future, SOA will often need to dynamically re-configuring and re-organizing its topologies of interactions between the web services because of some unpredictable events, such as crashes or network problems, which will cause service unavailability. Complexity and dynamism of the current and future global network system require service architecture that is capable of autonomously changing its structure and functionality to meet dynamic changes in the requirements and environment with little human intervention. This then needs to motivate the research described throughout this thesis. In this thesis, the idea of introducing autonomy and adapting case-based reasoning into SOA in order to extend the intelligence and capability of SOA is contributed and elaborated. It is conducted by proposing architecture of an autonomic SOA framework based on case-based reasoning and the architectural considerations of autonomic computing paradigm. It is then followed by developing and analyzing formal models of the proposed architecture using Petri Net. The framework is also tested and analyzed through case studies, simulation, and prototype development. The case studies show feasibility to employing case-based reasoning and autonomic computing into SOA domain and the simulation results show believability that it would increase the intelligence, capability, usability and robustness of SOA. It was shown that SOA can be improved to cope with dynamic environment and services unavailability by incorporating case-based reasoning and autonomic computing paradigm to monitor and analyze events and service requests, then to plan and execute the appropriate actions using the knowledge stored in knowledge database

Biologically Inspired Self-Healing Software System Architecture

Self-healing capabilities have begun to emerge as an interesting and potentially valuable property of software systems. Self-healing characteristic enables software systems to continuously and dynamically monitor, diagnose, and adapt itself after a failures has occur in their components. Adding such characteristic into existing software systems is immensely useful and valuable for allowing them to recover from failures. However, developing such self-healing software systems is a significant challenge. The nature introduces to us unforeseen concepts in terms of presenting biological systems that have the ability to handle its abnormal conditions. Based on this observation, this thesis presents self healing architecture for software system based on one of the biological processes that have the ability to heal by itself (the wound-healing process). The self-healing architecture provides software systems the ability to handle anomalous conditions that appear among its components. The presented architecture is divided into to layers, functional and healing layer. In the functional layer, the components of the system provide its services without any disruptions. The component is considered as faulty component if it fails to provide its services. The healing layer aims to heal the faulty component and return it to the running system without the awareness of the user. The presented self-healing software system is formally described to prove its functionality. Set-theoretic and Finite State Machine (FSM) is introduced. A prototype for the presented architecture has been implemented using Java language. Java objects are considered as the system components. The modules of the healing layer in the selfhealing architecture have been implemented into Java classes. An object from the module class will be created to perform its task for the healing process. The thesis concludes with recommendations for future works in this area and enhancement of the presented architecture