221 research outputs found

    Constructing a reproducible testing environment for distributed Java applications.

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    The emergence of the global Internet, wireless data communications, and the availability of powerful computers is enabling a new generation of distributed and concurrent systems. However, the inherent complexity of such systems introduces many new challenges in system testing and maintenance. One of the major problems in testing such systems is that executions with internal non-deterministic choices make the testing procedure non-repeatable. A natural solution is to artificially force the execution of a program to take desired paths so that a test can be reproduced. However, with geographically distributed processes and heterogeneous platform architectures, distributed systems have imposed new challenges in developing effective techniques for reproducible testing. The goal of this research is to build an environment to automate testing for distributed and concurrent Java applications. We will focus on controlling the order of occurrences of input and remote call events according to a user-specified test scenario, which is composed of input data, a constraint expressed as a partial order over the input and remote call events, and expected output. The testing environment is by itself distributed and does not require source code intrusion into the application under test. With minor changes, the testing components can also be reused in CORBA-based applications implemented in Java.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .W35. Source: Masters Abstracts International, Volume: 42-05, page: 1769. Adviser: Jessica Chen. Thesis (M.Sc.)--University of Windsor (Canada), 2003

    Refactoring middleware with aspects

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    Towards Adaptable and Adaptive Policy-Free Middleware

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    We believe that to fully support adaptive distributed applications, middleware must itself be adaptable, adaptive and policy-free. In this paper we present a new language-independent adaptable and adaptive policy framework suitable for integration in a wide variety of middleware systems. This framework facilitates the construction of adaptive distributed applications. The framework addresses adaptability through its ability to represent a wide range of specific middleware policies. Adaptiveness is supported by a rich contextual model, through which an application programmer may control precisely how policies should be selected for any particular interaction with the middleware. A contextual pattern mechanism facilitates the succinct expression of both coarse- and fine-grain policy contexts. Policies may be specified and altered dynamically, and may themselves take account of dynamic conditions. The framework contains no hard-wired policies; instead, all policies can be configured.Comment: Submitted to Dependable and Adaptive Distributed Systems Track, ACM SAC 200

    1 Patterns for Measuring Performance-related QoS Properties in Service-oriented Systems

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    In service-oriented systems, clients can access services via a network. Service level agreements (SLA) can exist, which specify — among other things — performance-related Quality of Service (QoS) properties between the client and the server, such as round-trip time, processing time, or availability. For a service provider serious financial consequences or other penalties can follow in case of not fulfilling the SLAs. The service consumer wants to evaluate that the provider complies with the guaranteed SLAs. Designing and developing a QoS-aware service-oriented system means facing many design challenges, such as where and how to measure the performance-related QoS properties. This paper presents design practices and patterns for measuring such QoS properties by extending and utilizing existing patterns. The focus of the patterns lies on the QoS measuring impact on the client’s or service’s performance, the extend of separation of concerns, the property of reusability, and the preciseness of the measured QoS properties. The patterns help to build efficient solutions to measure performance-related QoS properties in a service-oriented system

    Argos container, core and extension framework

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    With the emergence of the internet and e-commerce in the 90’s new common problems arose when developing applications that span the internet. These common problems include among others scalability, robustness, networking, database usage and heterogeneity. Software developers creating internet applications saw themselves reinventing the wheel repeatedly. This lead to the creation of middleware systems that aimed to solve these common problems. This thesis will present Argos which uses a different way of building middleware systems. Argos is able to provide tailored, flexible and extensible middleware support using reflection, dependency injection, Java Management Extensions (JMX) notifications and hot deployment. The result is a platform capable of tackling domain specific challenges. It provides rapid development of feature rich applications for managing and processing information. Argos has gone through thorough testing proving production stability

    A Component-Based Approach for Securing Indoor Home Care Applications

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    eHealth systems have adopted recent advances on sensing technologies together with advances in information and communication technologies (ICT) in order to provide people-centered services that improve the quality of life of an increasingly elderly population. As these eHealth services are founded on the acquisition and processing of sensitive data (e.g., personal details, diagnosis, treatments and medical history), any security threat would damage the public's confidence in them. This paper proposes a solution for the design and runtime management of indoor eHealth applications with security requirements. The proposal allows applications definition customized to patient particularities, including the early detection of health deterioration and suitable reaction (events) as well as security needs. At runtime, security support is twofold. A secured component-based platform supervises applications execution and provides events management, whilst the security of the communications among application components is also guaranteed. Additionally, the proposed event management scheme adopts the fog computing paradigm to enable local event related data storage and processing, thus saving communication bandwidth when communicating with the cloud. As a proof of concept, this proposal has been validated through the monitoring of the health status in diabetic patients at a nursing home.This work was financed under project DPI2015-68602-R (MINECO/FEDER, UE), UPV/EHU under project PPG17/56 and GV/EJ under recognized research group IT914-16

    Modeling Architectural Patterns Using Architectural Primitives

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