210 research outputs found

    Performance impact of the grid middleware

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    The Open Grid Services Architecture (OGSA) defines a new vision of the Grid based on the use of Web Services (Grid Services). The standard interfaces, behaviors and schemes that are consistent with the OGSA specification are defined by the Open Grid Service Infrastructure (OGSI). Grid Services, as an extension of the Web Services, run on top of rich execution frameworks that make them accessible and interoperable with other applications. Two examples of these frameworks are Sun’s J2EE platform and Microsoft’s .NET. The Globus Project implements the OGSI Specification for the J2EE framework in the Globus Toolkit. As any J2EE application, the performance of the Globus Toolkit is constrained by the performance obtained by the J2EE execution stack This performance can be influenced by many points of the execution stack: operating system, JVM, middleware or the same grid service, without forgetting the processing overheads related to the parsing of the communication protocols. In the scope of this chapter, all this levels together will be referred to as the grid middleware. In order to avoid the grid middleware to become a performance bottleneck for a distributed grid-enabled application, grid nodes have to be tuned for an efficient execution of I/O intensive applications because they can receive a high volume of requests every second and have to deal with a big amount of invocations, message parsing operations and a continuous task of marshaling and unmarshalling service parameters. All the parameters of the system affecting these operations have to be tuned according with the expected system load intensity. A Grid node is connected to to other nodes through a network connection which is also a decisive factor to obtain a high performance for a grid application. If the inter-node data transmission time overlaps completely the processing time for a computational task, the benefits of the grid architecture will be lost. Additionally, in many situations the content exchanged between grid nodes can be considered confidential and should be protected from curious sights. But the cost of data encryption/decryption can be an important performance weak that must be taken into account. In this chapter we will study the process of receiving and executing a Grid job from the perspective of the underlying levels existing below the Grid application. We will analyze the different performance parameters that can influence in the performance of the Grid middleware and will show the general schema of tasks involved in the service of an execution request.Postprint (author’s final draft

    Service-oriented architecture for device lifecycle support in industrial automation

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    Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de Computadores Especialidade: Robótica e Manufactura IntegradaThis thesis addresses the device lifecycle support thematic in the scope of service oriented industrial automation domain. This domain is known for its plethora of heterogeneous equipment encompassing distinct functions, form factors, network interfaces, or I/O specifications supported by dissimilar software and hardware platforms. There is then an evident and crescent need to take every device into account and improve the agility performance during setup, control, management, monitoring and diagnosis phases. Service-oriented Architecture (SOA) paradigm is currently a widely endorsed approach for both business and enterprise systems integration. SOA concepts and technology are continuously spreading along the layers of the enterprise organization envisioning a unified interoperability solution. SOA promotes discoverability, loose coupling, abstraction, autonomy and composition of services relying on open web standards – features that can provide an important contribution to the industrial automation domain. The present work seized industrial automation device level requirements, constraints and needs to determine how and where can SOA be employed to solve some of the existent difficulties. Supported by these outcomes, a reference architecture shaped by distributed, adaptive and composable modules is proposed. This architecture will assist and ease the role of systems integrators during reengineering-related interventions throughout system lifecycle. In a converging direction, the present work also proposes a serviceoriented device model to support previous architecture vision and goals by including embedded added-value in terms of service-oriented peer-to-peer discovery and identification, configuration, management, as well as agile customization of device resources. In this context, the implementation and validation work proved not simply the feasibility and fitness of the proposed solution to two distinct test-benches but also its relevance to the expanding domain of SOA applications to support device lifecycle in the industrial automation domain

    An investigation into interoperable end-to-end mobile web service security

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    The capacity to engage in web services transactions on smartphones is growing as these devices become increasingly powerful and sophisticated. This capacity for mobile web services is being realised through mobile applications that consume web services hosted on larger computing devices. This thesis investigates the effect that end-to-end web services security has on the interoperability between mobile web services requesters and traditional web services providers. SOAP web services are the preferred web services approach for this investigation. Although WS-Security is recognised as demanding on mobile hardware and network resources, the selection of appropriate WS-Security mechanisms lessens this burden. An attempt to implement such mechanisms on smartphones is carried out via an experiment. Smartphones are selected as the mobile device type used in the experiment. The experiment is conducted on the Java Micro Edition (Java ME) and the .NET Compact Framework (.NET CF) smartphone platforms. The experiment shows that the implementation of interoperable, end-to-end, mobile web services security on both platforms is reliant on third-party libraries. This reliance on third-party libraries results in poor developer support and exposes developers to the complexity of cryptography. The experiment also shows that there are no standard message size optimisation libraries available for both platforms. The implementation carried out on the .NET CF is also shown to rely on the underlying operating system. It is concluded that standard WS-Security APIs must be provided on smartphone platforms to avoid the problems of poor developer support and the additional complexity of cryptography. It is recommended that these APIs include a message optimisation technique. It is further recommended that WS-Security APIs be completely operating system independent when they are implemented in managed code. This thesis contributes by: providing a snapshot of mobile web services security; identifying the smartphone platform state of readiness for end-to-end secure web services; and providing a set of recommendations that may improve this state of readiness. These contributions are of increasing importance as mobile web services evolve from a simple point-to-point environment to the more complex enterprise environment

    Hyperautomation applied to Human Resources Processes

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    The goal of this master thesis is to utilize hyperautomation tools to design and implement solutions for two specific Human Resources processes: New Employee Admission and New Recruitment Needs. The objective is to create solutions that are readily adaptable to differ ent clients with minimal modifications necessary, while also maintaining a level of flexibility that permits for further customization to suit the specific needs and requirements of in dividual organizations. The ultimate goal is to improve the efficiency of the processes in question. The processes to be developed have already been created for a specific customer by the au thor while working at Roboyo, a company that specializes in Intelligent Process Automation (IPA). However, due to their high complexity, they cannot be easily replicated or imple mented for other clients. Therefore, the author aims to create solutions that are easily deployable into multiple customers, with minimal changes required. This will allow Roboyo to save time and resources, having a competitive advantage in the market, as they will be able to quickly and easily adapt to the needs of different customers The proposed solutions involve the integration and application of several advanced technologies, including Robotic Robotic Process Automation (RPA) to automate repetitive tasks and processes, Business Process Management (BPM) to optimize and streamline organizational operations,Optical Character Recognition (OCR) technology to extract and process written information, and Digital Signature technology to authenticate and secure electronic documents.O objectivo desta tese de mestrado é utilizar ferramentas de hiperautomação para conce ber e implementar soluções para dois processos específicos de Recursos Humanos: Admis são de Novos Colaboradores e Novas Necessidades de Recrutamento. O objectivo é criar soluções que sejam facilmente adaptáveis a diferentes clientes com o mínimo de modificações necessárias, mantendo ao mesmo tempo um nível de flexibilidade que permita uma maior adaptação às necessidades e requisitos específicos de cada organização. O objectivo final é melhorar a eficiência dos processos em questão. Os processos a serem desenvolvidos já foram criados para um cliente específico pelo autor en quanto trabalhava na Roboyo, uma empresa especializada em Intelligent Process Automation (IPA). Contudo, devido à sua elevada complexidade, não podem ser facilmente replicados ou implementados em outros clientes. Portanto, o autor pretende criar soluções que sejam facilmente implementáveis em múltiplos clientes, com o mínimo de alterações necessárias. Isto permitirá a Roboyo poupar tempo e recursos, tendo uma vantagem competitiva no mercado, uma vez que serão capazes de se adaptar rápido e facilmente às necessidades de diferentes clientes. As soluções propostas envolvem a integração e aplicação de várias tecnologias avançadas, incluindo Robotic Process Automation (RPA) para automatizar tarefas e processos repetitivos, Business Process Management (BPM) para otimizar e agilizar operações organizacionais, tecnologia Optical Character Recognition (OCR) para extrair e processar informação escrita e tecnologia de Assinatura Digital para autenticar e proteger documentos electrónicos

    Embarking service-oriented architecture into student information systems

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    Most organizations have more than one information system (IS) for their data and activity management. In Universiti Utara Malaysia (UUM), the Computer Centre is responsible for various IS related to students.However, none of these systems are fully interoperable in heterogeneous IS because they are using different types of database and programming language. This causes difficulties to automatically integrate data in the heterogeneous IS.As a result, the person in charge at each IS needs to do manual selections to get data from other IS. Consequently, the same tasks will be repeated since they have to enter and re enter similar data into different IS.In addition, this situation is increased the operation and maintenance cost, and waste the data storage space caused by the redundancy of data. Even though UUM has an IS that uses an integration tool for updating required data from the main student IS, it is still unable to update concurrent data on real-time and it needs one tool installed for each two IS to be integrated.This study aims to propose a conceptual model of the heterogeneous IS integration based on Service Oriented Architecture (SOA) concept.A case study approach was applied involving student IS in UUM because IS in a university are large, distributed and quite difficult to involve the whole IS with very limited time and cost.In validating the proposed conceptual model, this study uses experimental of prototyping and experts review. With the finding and result of this study, it is expected to produce a valid conceptual model of student IS based on SOA concept.Further, the model could serve as a guideline to related organizations in adopting SOA concept in improving the management of their IS integration

    Simplifying Cyber Foraging for Mobile Devices

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    Cyber foraging is the transient and opportunistic use of compute servers by mobile devices. The short market life of such devices makes rapid modification of applications for remote execution an important problem. We describe a solution that combines a “little language ” for cyber foraging with an adaptive runtime system. We report results from a user study showing that even novice developers are able to successfully modify large, unfamiliar applications in just a few hours. We also show that the quality of novice-modified and expert-modified applications are comparable in most cases. Categories and Subject Descriptor

    Lazy Services: A Service Oriented Architecture based on Incremental Computations and Commitments

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    A service oriented architecture (SOA) aims to structure complex distributed systems in terms of re-usable components, called services. To guarantee a good service interoperability these services must be weakly coupled and their description must be separated from their implementations. The interface of a service provides information on how it can be invoked: the logical location where it can be invoked, the supported communication protocol and the types of its input (parameters) and output (result). Traditionally, a service can only be invoked when its parameters are fully defined and, symmetrically, these services only return their results after they have been totally processed. In this paper, we promote a more liberal view of services by allowing them to consume their data lazily (i.e., as they need it) and produce their results incrementally (i.e., as they are produced). We develop this notion as 'lazy services' by building up from the model of guarded attributed grammars that was recently introduced in the context of distributed collaborative systems. We abstract from this model and limit somewhat its expressiveness so that it can comply more broadly to SOA principles. We introduce an improvement on subscription management to optimize the distributed implementation of lazy services

    La Salle University Graduate Catalog 2004-2005

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    https://digitalcommons.lasalle.edu/course_catalogs/1186/thumbnail.jp

    A Middleware framework for self-adaptive large scale distributed services

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    Modern service-oriented applications demand the ability to adapt to changing conditions and unexpected situations while maintaining a required QoS. Existing self-adaptation approaches seem inadequate to address this challenge because many of their assumptions are not met on the large-scale, highly dynamic infrastructures where these applications are generally deployed on. The main motivation of our research is to devise principles that guide the construction of large scale self-adaptive distributed services. We aim to provide sound modeling abstractions based on a clear conceptual background, and their realization as a middleware framework that supports the development of such services. Taking the inspiration from the concepts of decentralized markets in economics, we propose a solution based on three principles: emergent self-organization, utility driven behavior and model-less adaptation. Based on these principles, we designed Collectives, a middleware framework which provides a comprehensive solution for the diverse adaptation concerns that rise in the development of distributed systems. We tested the soundness and comprehensiveness of the Collectives framework by implementing eUDON, a middleware for self-adaptive web services, which we then evaluated extensively by means of a simulation model to analyze its adaptation capabilities in diverse settings. We found that eUDON exhibits the intended properties: it adapts to diverse conditions like peaks in the workload and massive failures, maintaining its QoS and using efficiently the available resources; it is highly scalable and robust; can be implemented on existing services in a non-intrusive way; and do not require any performance model of the services, their workload or the resources they use. We can conclude that our work proposes a solution for the requirements of self-adaptation in demanding usage scenarios without introducing additional complexity. In that sense, we believe we make a significant contribution towards the development of future generation service-oriented applications.Las Aplicaciones Orientadas a Servicios modernas demandan la capacidad de adaptarse a condiciones variables y situaciones inesperadas mientras mantienen un cierto nivel de servio esperado (QoS). Los enfoques de auto-adaptación existentes parecen no ser adacuados debido a sus supuestos no se cumplen en infrastructuras compartidas de gran escala. La principal motivación de nuestra investigación es inerir un conjunto de principios para guiar el desarrollo de servicios auto-adaptativos de gran escala. Nuesto objetivo es proveer abstraciones de modelaje apropiadas, basadas en un marco conceptual claro, y su implemetnacion en un middleware que soporte el desarrollo de estos servicios. Tomando como inspiración conceptos económicos de mercados decentralizados, hemos propuesto una solución basada en tres principios: auto-organización emergente, comportamiento guiado por la utilidad y adaptación sin modelos. Basados en estos principios diseñamos Collectives, un middleware que proveer una solución exhaustiva para los diversos aspectos de adaptación que surgen en el desarrollo de sistemas distribuidos. La adecuación y completitud de Collectives ha sido provada por medio de la implementación de eUDON, un middleware para servicios auto-adaptativos, el ha sido evaluado de manera exhaustiva por medio de un modelo de simulación, analizando sus propiedades de adaptación en diversos escenarios de uso. Hemos encontrado que eUDON exhibe las propiedades esperadas: se adapta a diversas condiciones como picos en la carga de trabajo o fallos masivos, mateniendo su calidad de servicio y haciendo un uso eficiente de los recusos disponibles. Es altamente escalable y robusto; puedeoo ser implementado en servicios existentes de manera no intrusiva; y no requiere la obtención de un modelo de desempeño para los servicios. Podemos concluir que nuestro trabajo nos ha permitido desarrollar una solucion que aborda los requerimientos de auto-adaptacion en escenarios de uso exigentes sin introducir complejidad adicional. En este sentido, consideramos que nuestra propuesta hace una contribución significativa hacia el desarrollo de la futura generación de aplicaciones orientadas a servicios.Postprint (published version
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