173 research outputs found

    A Model Based Approach on Multi-Agent System and Genetic Algorithm to Improve the Process Management in Service Oriented Architecture

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    Service oriented architecture is based on the provision of services. To enhance the performance of the systems by providing a better combination of services, it is necessary to extract more information compared to the one in the service registry. In this regard, the accomplished works have been focusing on the basic concepts of service-oriented architecture. The service composition is based on the information in service registry, provided by the service provider. Further, centralized combination with insufficient information does not meet the system performance requirements. This solution helps to facilitate resource distribution and reduces tasks of the central unit. In this paper, efforts have been made to use the agents in the proposed model to enhance the processes of a system. In the proposed model, agents have been used in order to extract and manage the essential information in service registry table. This information forms the basis of monitoring and selection of services. Agents are used for selecting and making efficient composite services. Finally, different communications and configuration mechanisms are implemented using multi-agent systems that can perform service-oriented architecture. Moreover, genetic algorithm is used to enhance architectural processes. In the proposed model, the genetic algorithm and multi-agent system has enhanced productivity of the system and its important quality attributes. The system runs in the international conference of computer society of Iran (ICCSI). Implementation of this model in the real environment and its comparison with its implementation on the prototype could be helpful to justify better efficiency and accuracy for future applications

    Fault Management For Service-Oriented Systems

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    Service Oriented Architectures (SOAs) enable the automatic creation of business applications from independently developed and deployed Web services. As Web services are inherently unreliable, how to deliver reliable Web services composition over unreliable Web services is a significant and challenging problem. The process requires monitoring the system\u27s behavior, determining when and why faults occur, and then applying fault prevention/recovery mechanisms to minimize the impact and/or recover from these faults. However, it is hard to apply a non-distributed management approach to SOA, since a manager needs to communicate with the different components through authentications. In SOA, a business process can terminate successfully if all services finish their work correctly through providing alternative plans in case of fault. However, the business process itself may encounter different faults because the fault may occur anywhere at any time due to SOA specifications. In this work, we propose new fault management technique (FLEX) and we identify several improvements over existing techniques. First, existing techniques rely mainly on static information while FLEX is based on dynamic information. Second, existing frameworks use a limited number of attributes; while we use all possible attributes by identify them as either required or optional. Third, FLEX reduces the comparison cost (time and space) by filtering out services at each level needed for evaluation. In general, FLEX is divided into two phases: Phase I, computes service reliability and utility, while in Phase II, runtime planning and evaluation. In Phase I, we assess the fault likelihood of the service using a combination of techniques (e.g., Hidden Marcov Model, Reputation, and Clustering). In Phase II, we build a recovery plan to execute in case of fault(s) and we calculate the overall system reliability based on the fault occurrence likelihoods assessed for all the services that are part of the current composition. FLEX is novel because it relies on key activities of the autonomic control loop (i.e., collect, analyze, decide, plan, and execute) to support dynamic management based on the changes of user requirements and QoS level. Our technique dynamically evaluates the performance of Web services based on their previous history and user requirements, assess the likelihood of fault occurrence, and uses the result to create (multiple) recovery plans. Moreover, we define a method to assess the overall system reliability by evaluating the performance of individual recovery plans, when invoked together. The Experiment results show that our technique improves the service selection quality by selecting the services with the highest score and improves the overall system performance in comparison with existing works. In the future, we plan to investigate techniques for monitoring service oriented systems and assess the online negotiation possibilities for combining different services to create high performance systems

    SLA-based trust model for secure cloud computing

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    Cloud computing has changed the strategy used for providing distributed services to many business and government agents. Cloud computing delivers scalable and on-demand services to most users in different domains. However, this new technology has also created many challenges for service providers and customers, especially for those users who already own complicated legacy systems. This thesis discusses the challenges of, and proposes solutions to, the issues of dynamic pricing, management of service level agreements (SLA), performance measurement methods and trust management for cloud computing.In cloud computing, a dynamic pricing scheme is very important to allow cloud providers to estimate the price of cloud services. Moreover, the dynamic pricing scheme can be used by cloud providers to optimize the total cost of cloud data centres and correlate the price of the service with the revenue model of service. In the context of cloud computing, dynamic pricing methods from the perspective of cloud providers and cloud customers are missing from the existing literature. A dynamic pricing scheme for cloud computing must take into account all the requirements of building and operating cloud data centres. Furthermore, a cloud pricing scheme must consider issues of service level agreements with cloud customers.I propose a dynamic pricing methodology which provides adequate estimating methods for decision makers who want to calculate the benefits and assess the risks of using cloud technology. I analyse the results and evaluate the solutions produced by the proposed scheme. I conclude that my proposed scheme of dynamic pricing can be used to increase the total revenue of cloud service providers and help cloud customers to select cloud service providers with a good quality level of service.Regarding the concept of SLA, I provide an SLA definition in the context of cloud computing to achieve the aim of presenting a clearly structured SLA for cloud users and improving the means of establishing a trustworthy relationship between service provider and customer. In order to provide a reliable methodology for measuring the performance of cloud platforms, I develop performance metrics to measure and compare the scalability of the virtualization resources of cloud data centres. First, I discuss the need for a reliable method of comparing the performance of various cloud services currently being offered. Then, I develop a different type of metrics and propose a suitable methodology to measure the scalability using these metrics. I focus on virtualization resources such as CPU, storage disk, and network infrastructure.To solve the problem of evaluating the trustworthiness of cloud services, this thesis develops a model for each of the dimensions for Infrastructure as a Service (IaaS) using fuzzy-set theory. I use the Takagi-Sugeno fuzzy-inference approach to develop an overall measure of trust value for the cloud providers. It is not easy to evaluate the cloud metrics for all types of cloud services. So, in this thesis, I use Infrastructure as a Service (IaaS) as a main example when I collect the data and apply the fuzzy model to evaluate trust in terms of cloud computing. Tests and results are presented to evaluate the effectiveness and robustness of the proposed model

    Multi-agent communication for the realization of business-processes

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    As Internet and information technologies expand further into daily business activities, new solutions and techniques are required to cope with the growing complexity. One area that has gained attention is systems and organizations interoperability and Service Oriented Architectures (SOA). Web Services have grown as a preferred technology in this area. Although these techniques have proved to solve problems of low level integration of heterogeneous systems, there has been little advance at higher levels of integration like how to rule complex conversations between participants that are autonomous and cannot depend on some ruling or orchestrating system. Multi-agent technology has studied techniques for content-rich communication, negotiation, autonomous problem solving and conversation protocols. These techniques have solved some of the problems that emerge when integrating autonomous systems to perform complex business processes. The present research work intends to provide a solution for the realization of complex Business Process between heterogeneous autonomous participants using multi-agent technology. We developed an integration of Web Services and agent-based technologies along with a model for creating conversation protocols that respect the autonomy of participants. A modeling tool has been developed to create conversation protocols in a modular and reusable manner. BDI-Agents implementations that communicate over Web Services are automatically generated out of these models.Internet und Informationstechnik finden immer mehr Verwendung in alltäglichen Geschäftsaktivitäten und als Folge dessen, werden neue Lösungen und Verfahren gebraucht, um der steigenden Komplexität gerecht zu werden. Insbesondere Bereiche wie System- und Organizations- Interoperabilität, wie auch dienst-orientierte Architekturen (SOA) haben demzufolge mehr Aufmerksamkeit bekommen. Dabei sind Web Services zur bevorzugten Technologie geworden. Tatsächlich haben diese Techniken Probleme in niedrigeren Ebenen gelöst, die beim lntegrieren von heterogenen Systemen entstehen. Allerdings gab es bisher weniger Fortschritte in höheren Ebenen, wie der Regelung von komplexen Dialogen zwischen Teilnehmern, die aufgrund ihrer Autonomie, sich nicht nach anderen kontrollierenden oder orchestrierenden Systemen richten lassen. Multiagenten-Systeme haben Bereiche wie inhaltreiche Kommunikation, Handel, autonome Problemlösung und Interaktionsprotokolle im Detail geforscht. Diese Techniken haben Probleme gelöst, die beim Ausführen von komplexen Geschäftsprozessen auftreten. Die vorliegende Doktorarbeit beabsichtigt, mit Verwendung von Multiagenten-Technologien, eine Lösung für die Umsetzung von komplexen Geschäftsprozessen zwischen heterogenen autonomen Teilnehmern bereitzustellen. Wir haben eine Integrationslösung für Web Services und agenten-basierte Technologien zur Verfügung gestellt, zusammen mit einem Model für die Erstellung von Interaktions-Protokollen, die die Autonomie der Teilnehmer berücksichtigt. Ein Modellierungstool wurde entwickelt, um modulare und wiederverwendbare Interaktionsprotokolle gestalten zu können. Aus diesen Modellen kann man auch Implementierungen automatisch erzeugen lassen, welche BDI-Agenten, die über Web Services kommunizieren, verwenden

    A History of the Royal (Toronto) Conservatory of Music Piano Examinations, 1887-2015: Their Impact and Influence

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    Since its inception in 1887, the Royal Conservatory of Music has maintained its position as one of the largest and oldest community-based music schools and education centres in North America, with an integrated examination body and a comprehensive graded curriculum, influencing and shaping the Canadian musical landscape. For the past 130 years, the Conservatory has presented a wide-ranging art music repertoire for studying piano and offered a comprehensive system for assessing students progress through its Examinations, recently retitled as The Certificate Program. The Conservatorys internal examinations began in 1887, with the external examinations following in 1898. The latter preserved the format of the former and expanded through increasing the number of the examination centres across Canada for both financial and educational reasons. Despite varying opinions of professionals and amateurs on the efficacy and value of the piano examinations in particular from the beginning, this dissertation, using historical sources and interviews, argues that over the years the structure and content of the piano examinations, while innately conservative on the whole, have kept up with a changing demographic of students across the country, and either countered or taken on the many criticisms that surrounded them over the years despite geographical and financial challenges, and indeed competition from other institutions. Recently they have been hardy enough to enter the American market. Overall, the Conservatorys examination system has created a cultural asset ideal for a country such as Canada, providing, promoting, and disseminating both the branded curriculum and controlled assessment, which contributed to the development and improvement of music education rapidly and effectively. A distinctive part of the dissertation in addition to its detailed history is the interviews with current examiners and teachers, who face a whole new set of challenges and uncharted waters as technology offers new approaches to teaching and evaluation. In this ethnographic approach, their voices add a whole new dimension to the historical survey of the examinations system, arguing that despiteor perhaps because ofthe weight of tradition they still have much to offer

    Ontology driven multi-agent systems : an architecture for sensor web applications.

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    Thesis (Ph.D.)-University of KwaZulu-Natal, 2009.Advances in sensor technology and space science have resulted in the availability of vast quantities of high quality earth observation data. This data can be used for monitoring the earth and to enhance our understanding of natural processes. Sensor Web researchers are working on constructing a worldwide computing infrastructure that enables dynamic sharing and analysis of complex heterogeneous earth observation data sets. Key challenges that are currently being investigated include data integration; service discovery, reuse and composition; semantic interoperability; and system dynamism. Two emerging technologies that have shown promise in dealing with these challenges are ontologies and software agents. This research investigates how these technologies can be integrated into an Ontology Driven Multi-Agent System (ODMAS) for the Sensor Web. The research proposes an ODMAS framework and an implemented middleware platform, i.e. the Sensor Web Agent Platform (SWAP). SWAP deals with ontology construction, ontology use, and agent based design, implementation and deployment. It provides a semantic infrastructure, an abstract architecture, an internal agent architecture and a Multi-Agent System (MAS) middleware platform. Distinguishing features include: the incorporation of Bayesian Networks to represent and reason about uncertain knowledge; ontologies to describe system entities such as agent services, interaction protocols and agent workflows; and a flexible adapter based MAS platform that facilitates agent development, execution and deployment. SWAP aims to guide and ease the design, development and deployment of dynamic alerting and monitoring applications. The efficacy of SWAP is demonstrated by two satellite image processing applications, viz. wildfire detection and monitoring informal settlement. This approach can provide significant benefits to a wide range of Sensor Web users. These include: developers for deploying agents and agent based applications; end users for accessing, managing and visualising information provided by real time monitoring applications, and scientists who can use the Sensor Web as a scientific computing platform to facilitate knowledge sharing and discovery. An Ontology Driven Multi-Agent Sensor Web has the potential to forever change the way in which geospatial data and knowledge is accessed and used. This research describes this far reaching vision, identifies key challenges and provides a first step towards the vision

    A reactive architecture for cloud-based system engineering

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    PhD ThesisSoftware system engineering is increasingly practised over globally distributed locations. Such a practise is termed as Global Software Development (GSD). GSD has become a business necessity mainly because of the scarcity of resources, cost, and the need to locate development closer to the customers. GSD is highly dependent on requirements management, but system requirements continuously change. Poorly managed change in requirements affects the overall cost, schedule and quality of GSD projects. It is particularly challenging to manage and trace such changes, and hence we require a rigorous requirement change management (RCM) process. RCM is not trivial in collocated software development; and with the presence of geographical, cultural, social and temporal factors, it makes RCM profoundly difficult for GSD. Existing RCM methods do not take into consideration these issues faced in GSD. Considering the state-of-the-art in RCM, design and analysis of architecture, and cloud accountability, this work contributes: 1. an alternative and novel mechanism for effective information and knowledge-sharing towards RCM and traceability. 2. a novel methodology for the design and analysis of small-to-medium size cloud-based systems, with a particular focus on the trade-off of quality attributes. 3. a dependable framework that facilitates the RCM and traceability method for cloud-based system engineering. 4. a novel methodology for assuring cloud accountability in terms of dependability. 5. a cloud-based framework to facilitate the cloud accountability methodology. The results show a traceable RCM linkage between system engineering processes and stakeholder requirements for cloud-based GSD projects, which is better than existing approaches. Also, the results show an improved dependability assurance of systems interfacing with the unpredictable cloud environment. We reach the conclusion that RCM with a clear focus on traceability, which is then facilitated by a dependable framework, improves the chance of developing a cloud-based GSD project successfully

    Semantic discovery and reuse of business process patterns

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    Patterns currently play an important role in modern information systems (IS) development and their use has mainly been restricted to the design and implementation phases of the development lifecycle. Given the increasing significance of business modelling in IS development, patterns have the potential of providing a viable solution for promoting reusability of recurrent generalized models in the very early stages of development. As a statement of research-in-progress this paper focuses on business process patterns and proposes an initial methodological framework for the discovery and reuse of business process patterns within the IS development lifecycle. The framework borrows ideas from the domain engineering literature and proposes the use of semantics to drive both the discovery of patterns as well as their reuse

    Development and Evaluation of a Holistic, Cloud-driven and Microservices-based Architecture for Automated Semantic Annotation of Web Documents

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    The Semantic Web is based on the concept of representing information on the web such that computers can both understand and process them. This implies defining context for web information to give them a well-defined meaning. Semantic Annotation defines the process of adding annotation data to web information for the much-needed context. However, despite several solutions and techniques for semantic annotation, it is still faced with challenges which have hindered the growth of the semantic web. With recent significant technological innovations such as Cloud Computing, Internet of Things as well as Mobile Computing and their various integrations with semantic technologies to proffer solutions in IT, little has been done towards leveraging these technologies to address semantic annotation challenges. Hence, this research investigates leveraging cloud computing paradigm to address some semantic annotation challenges, with focus on an automated system for providing semantic annotation as a service. Firstly, considering the current disparate nature observable with most semantic annotation solutions, a holistic perspective to semantic annotation is proposed based on a set of requirements. Then, a capability assessment towards the feasibility of leveraging cloud computing is conducted which produces a Cloud Computing Capability Model for Holistic Semantic Annotation. Furthermore, an investigation into application deployment patterns in the cloud and how they relate to holistic semantic annotation was conducted. A set of determinant factors that define different patterns for application deployment in the cloud were identified and these resulted into the development of a Cloud Computing Maturity Model and the conceptualisation of a “Cloud-Driven” development methodology for holistic semantic annotation in the cloud. Some key components of the “Cloud-Driven” concept include Microservices, Operating System-Level Virtualisation and Orchestration. With the role Microservices Software Architectural Patterns play towards developing solutions that can fully maximise cloud computing benefits; CloudSea: a holistic, cloud-driven and microservices-based architecture for automated semantic annotation of web documents is proposed as a novel approach to semantic annotation. The architecture draws from the theory of “Design Patterns” in Software Engineering towards its design and development which subsequently resulted into the development of twelve Design Patterns and a Pattern Language for Holistic Semantic Annotation, based on the CloudSea architectural design. As proof-of-concept, a prototype implementation for CloudSea was developed and deployed in the cloud based on the “Cloud-Driven” methodology and a functionality evaluation was carried out on it. A comparative evaluation of the CloudSea architecture was also conducted in relation to current semantic annotation solutions; both proposed in academic literature and existing as industry solutions. In addition, to evaluate the proposed Cloud Computing Maturity Model for Holistic Semantic Annotation, an experimental evaluation of the model was conducted by developing and deploying six instances of the prototype and deploying them differently, based on the patterns described in the model. This empirical investigation was implemented by testing the instances for performance through series of API load tests and results obtained confirmed the validity of both the “Cloud-Driven” methodology and the entire model

    Development and Evaluation of a Holistic, Cloud-driven and Microservices-based Architecture for Automated Semantic Annotation of Web Documents

    Get PDF
    The Semantic Web is based on the concept of representing information on the web such that computers can both understand and process them. This implies defining context for web information to give them a well-defined meaning. Semantic Annotation defines the process of adding annotation data to web information for the much-needed context. However, despite several solutions and techniques for semantic annotation, it is still faced with challenges which have hindered the growth of the semantic web. With recent significant technological innovations such as Cloud Computing, Internet of Things as well as Mobile Computing and their various integrations with semantic technologies to proffer solutions in IT, little has been done towards leveraging these technologies to address semantic annotation challenges. Hence, this research investigates leveraging cloud computing paradigm to address some semantic annotation challenges, with focus on an automated system for providing semantic annotation as a service. Firstly, considering the current disparate nature observable with most semantic annotation solutions, a holistic perspective to semantic annotation is proposed based on a set of requirements. Then, a capability assessment towards the feasibility of leveraging cloud computing is conducted which produces a Cloud Computing Capability Model for Holistic Semantic Annotation. Furthermore, an investigation into application deployment patterns in the cloud and how they relate to holistic semantic annotation was conducted. A set of determinant factors that define different patterns for application deployment in the cloud were identified and these resulted into the development of a Cloud Computing Maturity Model and the conceptualisation of a “Cloud-Driven” development methodology for holistic semantic annotation in the cloud. Some key components of the “Cloud-Driven” concept include Microservices, Operating System-Level Virtualisation and Orchestration. With the role Microservices Software Architectural Patterns play towards developing solutions that can fully maximise cloud computing benefits; CloudSea: a holistic, cloud-driven and microservices-based architecture for automated semantic annotation of web documents is proposed as a novel approach to semantic annotation. The architecture draws from the theory of “Design Patterns” in Software Engineering towards its design and development which subsequently resulted into the development of twelve Design Patterns and a Pattern Language for Holistic Semantic Annotation, based on the CloudSea architectural design. As proof-of-concept, a prototype implementation for CloudSea was developed and deployed in the cloud based on the “Cloud-Driven” methodology and a functionality evaluation was carried out on it. A comparative evaluation of the CloudSea architecture was also conducted in relation to current semantic annotation solutions; both proposed in academic literature and existing as industry solutions. In addition, to evaluate the proposed Cloud Computing Maturity Model for Holistic Semantic Annotation, an experimental evaluation of the model was conducted by developing and deploying six instances of the prototype and deploying them differently, based on the patterns described in the model. This empirical investigation was implemented by testing the instances for performance through series of API load tests and results obtained confirmed the validity of both the “Cloud-Driven” methodology and the entire model
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