Along withthe development of multicore architectures and cloud computing, concurrent programming and computation becomes a huge challenge for application developers. distributed environment turns into complexity and ...
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Along withthe development of multicore architectures and cloud computing, concurrent programming and computation becomes a huge challenge for application developers. distributed environment turns into complexity and unpredictability. So it is important to improve programming models on language level to make it possible for programmers unfamiliar withdistributed systems to build large-scale applications. Erlang is an actor-based functional programming language that provides language level elements for concurrency. It has capability of describing large quantities of concurrent actions by multiple-process, which communicates asynchronously by sending and receiving messages. But it lacks of data structures and mechanism of language level for inherent concurrent units with a simple way of interaction, which may impede programmers in concurrent programming. Comparing with other computing element models such as Active object and Concurrent Agent, we extend Erlang with a new computing element called "EIC_Unit" and a way of interaction by "futures". It makes programmers to develop concurrent applications more easily and convenient in a distributed environment.
the energy efficiency becomes one of the most important concerns in mobile electronic systems design with mandatory requirements for low energy consumption, long battery life and low heat dissipation. Dynamic Power Ma...
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the energy efficiency becomes one of the most important concerns in mobile electronic systems design with mandatory requirements for low energy consumption, long battery life and low heat dissipation. Dynamic Power Management (DPM) and Dynamic Voltage and Frequency Scaling (DVFS or DVS) are two widely applied system level techniques to conserve system-wide power consumption. In the context of hard real-time systems, however, DPM and DVS have to be used with great caution in terms of timing constraints. In this article, we study the combined application of DPM and DVS for componentoriented systems with hard real-time tasks and propose a simulated annealing based optimization algorithm and its online execution with constant complexity at each scheduling point. Additionally, our approach considers multiple low power states (sleep states) with non-negligible switching overhead. the experimental results show that our approach can achieve almost an optimal solution.
As the foundation of cloud computing, Server consolidation allows multiple computer infrastructures running as virtual machines in a single physical node. It improves the utilization of most kinds of resource but memo...
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Agent-based modeling and simulation is a way to model the behavior of populations of components and their interactions within a system. the key of this approach is to model the components of the system as autonomous a...
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System execution traces are useful artifacts for validating distributed system quality-of-service (QoS) properties, such as end-to-end response time, throughput, and service time. With proper planning during developme...
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System execution traces are useful artifacts for validating distributed system quality-of-service (QoS) properties, such as end-to-end response time, throughput, and service time. With proper planning during development phase of the software lifecycle, it is possible to ensure such traces contain required properties to facilitate analysis for QoS validation. In some case, however, it is not possible to ensure system execution traces contain the necessary properties for QoS analysis. this paper presents the System Execution Trace Adaptation Framework (SETAF) for adapting system execution traces to support analysis of QoS properties. It also presents results from applying SETAF to externally developed applications. the results show that it is possible to validate QoS properties by automatically adapting system execution traces at analysis time instead of modifying the application's existing source code.
Many recent applications involve processing and analyzing uncertain data. Recently, several research efforts have addressed answering skyline queries efficiently on massive uncertain datasets. However, the research la...
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Many recent applications involve processing and analyzing uncertain data. Recently, several research efforts have addressed answering skyline queries efficiently on massive uncertain datasets. However, the research lacks methods to compute these queries on uncertain data, where each dimension of the uncertain object is represented as an interval or an exact value. In this paper, we extensively study the problem of skyline query on these interval based uncertain objects, which has never been studied before. We first model the problem of querying the skylines on interval datasets. Typically, we address two efficient algorithms with I/O optimal for the conventional interval skyline queries and constrained interval skyline queries, respectively. Extensive experiments demonstrate the efficiency of all our proposed algorithms.
Compared to the conventional physical cluster, the virtual cluster technology has features such as flexible configuration, easy management and high system security, which provides users with an easily customized compu...
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Compared to the conventional physical cluster, the virtual cluster technology has features such as flexible configuration, easy management and high system security, which provides users with an easily customized computing environment. Virtual machine image files as the most important stored objects in the virtual computing environment include all the information about the whole life cycle of virtual machine. the storage of the virtual machine images is an important part of virtual computing. there are mainly two ways to store the images, which include local storage and networking storage. this paper proposes a mechanism to manage the distributed image files to support the virtual computing environment. It uses the computing nodes` local storage as a chunk server in a distributed file system, and regards the distribution of the image files as a primary factor to choose the computing node to deploy virtual machine and to implement a backup mechanism of distributed images based on historical records of image files. Functional test and performance test results show that it can effectively support the virtual computing environment and has great values of applications and research.
this paper presents the development of REF-WS an approach to enable a Web Service provider to reliably evolve their service through the application of refactoring transformations. REF-WS is intended to aid service pro...
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this paper presents the development of REF-WS an approach to enable a Web Service provider to reliably evolve their service through the application of refactoring transformations. REF-WS is intended to aid service providers, particularly in a reliability and performance constrained domain as it permits upgraded 'non-backwards compatible' services to be deployed into a performance constrained network where existing consumers depend on an older version of the service interface. In order for this to be successful, the refactoring and message mediation needs to occur without affecting functional compatibility withthe services' consumers, and must operate within the performance overhead expected of the original service, introducing as little latency as possible. Furthermore, compared to a manually programmed solution, the presented approach enables the service developer to apply and parameterize refactorings with a level of confidence that they will not produce an invalid or 'corrupt' transformation of messages. this is achieved through the use of preconditions for the defined refactorings.
作者：
Kay KlobedanzWolfgang MuellerAchim RettbergC-LAB
Faculty of Electrical Engineering Computer Science and Mathematics University of Paderborn Paderborn Germany Faculty II
Department Computer Science Carl von Ossietzky University슠of슠Oldenburg Oldenburg Germany
In this paper we present an approach for the self reconfiguration of distributed micro-controllers for increased fault tolerance. Based on a modified distributed system topology utilizing a time division multiple acce...
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In this paper we present an approach for the self reconfiguration of distributed micro-controllers for increased fault tolerance. Based on a modified distributed system topology utilizing a time division multiple access (TDMA) protocol, i.e., Flex Ray, we present a self-organized distributed coordinator concept which performs the self-reconfiguration in the case of node failures. We introduce a distributed coordinator, which utilizes redundant slots in the Flex Ray communication schedule and combines messages in configured protocol frames and slots to avoid a complete bus restart. As such, the self-reconfiguration is realized by means of predetermined information about resulting changes in the communication dependencies and (re-)assignments determined in the design phase. To retrieve the necessary information, we present an analytical approach, which determines a combined solution for the initial configuration and all possible reconfigurations for the remaining nodes of the Flex Ray network in case of node failures. Hence, through this method we can design self-reconfiguring network-based systems enabling the handling of node failures for an increased fault tolerance.
the complexity of software in safety critical systems has increased significantly over the last ten years so that how to tackle the complexity and gain high dependable software plays an important roles in ensuring the...
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