2,302 research outputs found

    Context-aware adaptation in DySCAS

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    DySCAS is a dynamically self-configuring middleware for automotive control systems. The addition of autonomic, context-aware dynamic configuration to automotive control systems brings a potential for a wide range of benefits in terms of robustness, flexibility, upgrading etc. However, the automotive systems represent a particularly challenging domain for the deployment of autonomics concepts, having a combination of real-time performance constraints, severe resource limitations, safety-critical aspects and cost pressures. For these reasons current systems are statically configured. This paper describes the dynamic run-time configuration aspects of DySCAS and focuses on the extent to which context-aware adaptation has been achieved in DySCAS, and the ways in which the various design and implementation challenges are met

    Customizing Component Middleware for Distributed Real-Time Systems with Aperiodic and Periodic Tasks

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    Many distributed real-time applications must handle mixed aperiodic and periodic tasks with diverse requirements. However, existing middleware lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different applications with both aperiodic and periodic tasks. The primary contribution of this work is the design, implementation and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic tasks in distributed real-time systems. Empirical results demonstrate the need for, and the effectiveness of, our configurable component middleware approach in supporting different applications with aperiodic and periodic tasks

    Quality assessment technique for ubiquitous software and middleware

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    The new paradigm of computing or information systems is ubiquitous computing systems. The technology-oriented issues of ubiquitous computing systems have made researchers pay much attention to the feasibility study of the technologies rather than building quality assurance indices or guidelines. In this context, measuring quality is the key to developing high-quality ubiquitous computing products. For this reason, various quality models have been defined, adopted and enhanced over the years, for example, the need for one recognised standard quality model (ISO/IEC 9126) is the result of a consensus for a software quality model on three levels: characteristics, sub-characteristics, and metrics. However, it is very much unlikely that this scheme will be directly applicable to ubiquitous computing environments which are considerably different to conventional software, trailing a big concern which is being given to reformulate existing methods, and especially to elaborate new assessment techniques for ubiquitous computing environments. This paper selects appropriate quality characteristics for the ubiquitous computing environment, which can be used as the quality target for both ubiquitous computing product evaluation processes ad development processes. Further, each of the quality characteristics has been expanded with evaluation questions and metrics, in some cases with measures. In addition, this quality model has been applied to the industrial setting of the ubiquitous computing environment. These have revealed that while the approach was sound, there are some parts to be more developed in the future

    A Generative Programming Framework for Adaptive Middleware

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    Historically, many distributed real-time and embedded (DRE) systems were developed manually from scratch, leading to stove-piped solutions that while correct in both functional and QoS properties were very expensive to develop and difficult to maintain and extend. First-generation middleware technologies such as CORBA 2.x [1], XML [2], and SOAP [3], served to shield application developers from low-level platform details, thus raising the level of abstraction at which distributed systems are developed and supporting reuse of infrastructure to amortize development costs over the lifetime of a system. However, interdependencies between services and object interfaces resulting from these programming models significantly limited the degree of reuse that could be achieved in practice. Component middleware technologies such as the CORBA Component Model (CCM) [4], J2EE [5], and .NET [6], were developed to address many of these limitations. In CCM, for example, standardization of component containers, ports, and homes offered a framework within which reuse of server as well as client infrastructure was facilitated. Component-oriented middleware has addressed a wide range of application domains, but unfortunately for DRE systems, the focus of these technologies has been primarily on functional and not QoS properties. For example, although CCM supports configuration of functional component attributes like their interconnections, key QoS attributes for DRE systems, such as execution times and invocation rates are inadequately configurable through conventional CCM [7]. Research on QoS-aware component models such as the CIAO project [8, 7] is showing significant promise in making QoS configuration a first-class part of the component pro-gramming model, thus further reducing accidental complex-ities of building DRE systems. However, it is important to note a fundamental difference between configuration of functional and QoS properties even within such a unified compo-nent model: the dominant decomposition of functional properties is essentially object-oriented, while the dominant decomposition of QoS properties is essentially aspect-oriented. That is, functional properties tend to be stable with respect to component boundaries and configuration lifecycle stages, while QoS properties tend to cross-cut component boundaries, and may be revised as more information is known in later configuration stages [7]. In this paper, we describe how a focus on aspect frameworks for configuring QoS properties both com-plements and extends QoS-aware component models. This paper makes three main contributions to the state of the art in DRE systems middleware. First, it describes a simple but representative problem for configuring QoS aspects that cross-cut both architectural layers and system lifecycle boundaries, which motivates our focus on aspect frameworks. Second, it provides a formalization of that problem using first order logic, which both guides the design of aspect configuration infrastructure, and offers a way to connect these techniques with model-integrated computing [9] approaches to further reduce the programming burden on DRE system developers. Third, it describes alternative mechanisms to ensure correct configuration of the aspects involved, and notes the phases of the DRE system lifecycle at which each such configuration mechanism is most appropriate

    Reconfigurable Real-Time Middleware for Distributed Cyber-Physical Systems with Aperiodic Events

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    Different distributed cyber-physical systems must handle aperiodic and periodic events with diverse requirements. While existing real-time middleware such as Real-Time CORBA has shown promise as a platform for distributed systems with time constraints, it lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different cyber-physical systems with both aperiodic and periodic events. The primary contribution of this work is the design, implementation and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic event handling in distributed cyber-physical systems. Empirical results demonstrate the need for, and the effectiveness of, our configurable component middleware approach in supporting different applications with aperiodic and periodic events, and providing a flexible software platform for distributed cyber-physical systems with end-to-end timing constraints

    Towards a Reconfiguration Service for Distributed Real-Time Java

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    REACTION 2012. 1st International workshop on Real-time and distributed computing in emerging applications. December 4th, 2012, San Juan, Puerto Rico.Ancient monolithic distributed systems were attached to well-known development practices and offline analysis. Current scenarios are more dynamic, and open, plenty of applications and services which appear and disappear dynamically at runtime. Likewise, these scenarios require taking into account actions that were traditionally addressed offline, this time in an online scenario. This paper contributes a reconfiguration service in the context of distributed real-time Java application as a means to include real-time reconfiguration into next generation real-time Java systems. The paper addresses the integration taking into account changes required in the API and the cost of some reconfiguration strategies.This research was partially supported by the European Commission (ARTIST2 NoE, ST-2004-004527; iLAND ARTEMIS-JU Call 1) and by the Spanish national project REM4VSS (TIN-2011-28339)

    An Architectural Approach to Autonomics and Self-management of Automotive Embedded Electronic Systems

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    International audienceEmbedded electronic systems in vehicles are of rapidly increasing commercial importance for the automotive industry. While current vehicular embedded systems are extremely limited and static, a more dynamic configurable system would greatly simplify the integration work and increase quality of vehicular systems. This brings in features like separation of concerns, customised software configuration for individual vehicles, seamless connectivity, and plug-and-play capability. Furthermore, such a system can also contribute to increased dependability and resource optimization due to its inherent ability to adjust itself dynamically to changes in software, hardware resources, and environment condition. This paper describes the architectural approach to achieving the goals of dynamically self-configuring automotive embedded electronic systems by the EU research project DySCAS. The architecture solution outlined in this paper captures the application and operational contexts, expected features, middleware services, functions and behaviours, as well as the basic mechanisms and technologies. The paper also covers the architecture conceptualization by presenting the rationale, concerning the architecture structuring, control principles, and deployment concept. In this paper, we also present the adopted architecture V&V strategy and discuss some open issues in regards to the industrial acceptance

    Dynamic CPU management for real-time, middleware-based systems

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    Journal ArticleMany real-world distributed, real-time, embedded (DRE) systems, such as multi-agent military applications, are built using commercially available operating systems, middleware, and collections of pre-existing software. The complexity of these systems makes it difficult to ensure that they maintain high quality of service (QOS). At design time, the challenge is to introduce coordinated QOS controls into multiple software elements in a non-invasive manner. At run time, the system must adapt dynamically to maintain high QOS in the face of both expected events, such as application mode changes, and unexpected events, such as resource demands from other applications. In this paper we describe the design and implementation of a CPU Broker for these types of DRE systems. The CPU Broker mediates between multiple real-time tasks and the facilities of a real-time operating system: using feedback and other inputs, it adjusts allocations over time to ensure that high application-level QOS is maintained. The broker connects to its monitored tasks in a non-invasive manner, is based on and integrated with industry-standard middleware, and implements an open architecture for new CPU management policies. Moreover, these features allow the broker to be easily combined with other QOS mechanisms and policies, as part of an overall end-to-end QOS management system. We describe our experience in applying the CPU Broker to a simulated DRE military system. Our results show that the broker connects to the system transparently and allows it to function in the face of run-time CPU resource contention

    Roadmap Analysis of Protein-Protein Interactions. Master\u27s Thesis, August 2007

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    The ability to effectively model the interaction between proteins is an important and open problem. In molecular biology it is well accepted that from sequence arises form and from form arises function but relating structure to function remains a challenge. The function of a given protein is defined by its interactions. Likewise a malfunction or a change in protein-protein interactions is a hallmark of many diseases. Many researchers are studying the mechanisms of protein-protein interactions and one of the overarching goals of the community is to predict whether two proteins will bind, and if so what the final conformation will be. Attention is seldom paid to the association pathways that allow two proteins to bind. Evidence has shown that the information in the association pathways can play a vital role in understanding the interaction itself. This thesis presents a novel and scalable approach to computing association pathways between two proteins using the Probabilistic Roadmap (PRM) framework. We will discuss the challenges in extending PRM to the domain of protein-protein interactions such as performing structural mappings in a reduced space of flexibility, and sampling high dimensional conformation spaces. We will present analysis of individual association pathways as well as methods for estimating collective properties of the energy landscape. Our results indicate that these methods can discriminate between true and false protein binding interfaces. Finally, we will present condensing methods such as pathway clustering and visualization using dimensionality reduction that can be be applied to create compact representations of the interaction space
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