The Inspector/Executor is well-known for parallelizing loops with irregular access patterns that cannot be analyzed statically. The downsides of existing inspectors are that it is hard to amortize their high run-time ...
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We introduce BANpipe - a logic-based scripting language designed to model complex compositions of time consuming analyses. Its declarative semantics is described together with alternative operational semantics facilit...
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Event-based systems (EBS) are widely used to efficiently process massively parallel data streams. In distributed event processing the allocation of event detectors to machines is crucial for both the latency and effic...
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ISBN:
(纸本)9781467363822
Event-based systems (EBS) are widely used to efficiently process massively parallel data streams. In distributed event processing the allocation of event detectors to machines is crucial for both the latency and efficiency, and a naive allocation may even cause a system failure. But since data streams, network traffic, and event loads cannot be predicted sufficiently well the optimal detector allocation cannot be found a-priori and must instead be determined at runtime. This paper describes how evolutionary algorithms (EA) can be used to minimize both network and processing latency by means of runtime migration of event detectors. The paper qualitatively evaluates the algorithms on synthetical data streams in a distributed event-based system. We show that some EAs work efficiently even with large numbers of event detectors and machines and that a hybrid of Cuckoo Search and Particle Swarm Optimization outperforms others.
In surveillance, sports, finances, etc., distributed event-based systems are used to detect meaningful events with low latency in high data rate event streams. Both known approaches to deal with the predominant out-of...
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R is an environment and functional programming language for statistical data analysis and visualization. Largely unknown to the functional programming community, it is popular and influential in many empirical science...
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In this paper, we show the power of combining modern synthesis technology with a constraint-oriented approach to variability modeling. This combination guarantees the validity of all the required properties simply by ...
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For scientists, it is advantageous to use a high level of abstraction for programming their simulations, so that they can focus on the problem at hand instead of struggling with low-level details. However, current HPC...
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ISBN:
(纸本)9781467362399
For scientists, it is advantageous to use a high level of abstraction for programming their simulations, so that they can focus on the problem at hand instead of struggling with low-level details. However, current HPC clusters with multiple GPUs per node only offer explicit communication to and from the GPUs, require manual work to keep the data consistent, and often need explicit kernel programming. Moreover, known GPU programming frameworks are limited to a single GPU or a single machine and also rarely support objects. Our system removes the above restrictions. With a slight but necessary change in Java's semantics, we achieve automatic distribution and efficient use of objects and arrays of objects on multiple GPUs in a cluster. On benchmarks that distribute arrays of objects over five machines with 10 GPUs, we achieve speedups of up to 4.9 compared to one node.
Today's software for aerospace systems typically is very complex. This is due to the increasing number of features as well as the high demand for safety, reliability, and quality. This complexity also leads to sig...
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ISBN:
(纸本)9781467318129
Today's software for aerospace systems typically is very complex. This is due to the increasing number of features as well as the high demand for safety, reliability, and quality. This complexity also leads to significant higher software development costs. To handle the software complexity, a structured development process is necessary. Additionally, compliance with relevant standards for quality assurance is a mandatory concern. To assure high software quality, techniques for verification are necessary. Besides traditional techniques like testing, automated verification techniques like model checking become more popular. The latter examine the whole state space and, consequently, result in a full test coverage. Nevertheless, despite the obvious advantages, this technique is rarely yet used for the development of aerospace systems. In this paper, we propose a tool-supported methodology for the development and formal verification of safety-critical software in the aerospace domain. The methodology relies on the V-Model and defines a comprehensive work flow for model-based software development as well as automated verification in compliance to the European standard series ECSS-E-ST-40C. Furthermore, our methodology supports the generation and deployment of code. For tool support we use the tool SCADE Suite (Esterel Technology), an integrated design environment that covers all the requirements for our methodology. The SCADE Suite is well established in avionics and defense, rail transportation, energy and heavy equipment industries. For evaluation purposes, we apply our approach to an up-to-date case study of the TET-1 satellite bus. In particular, the attitude and orbit control software is considered. The behavioral models for the subsystem are developed, formally verified, and optimized.
We present a systematic approach to the automatic generation of platform-independent benchmarks of tailored complexity for evaluating verification tools for reactive systems. Key to this approach is a tool chain that ...
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In this paper, we present PDP, a distributed polling protocol that enables a set of participants to gather their opinion on a common interest without revealing their point of view. PDP does not rely on any centralized...
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In this paper, we present PDP, a distributed polling protocol that enables a set of participants to gather their opinion on a common interest without revealing their point of view. PDP does not rely on any centralized authority or on heavyweight cryptography. PDP is an overlay-based protocol where a subset of participants may use a simple sharing scheme to express their votes. In a system of M participants arranged in groups of size N where at least 2k-1 participants are honest, PDP bounds the probability for a given participant to have its vote recovered with certainty by a coalition of B dishonest participants by π(B/N) (k+1) , where π is the proportion of participants splitting their votes, and k a privacy parameter. PDP bounds the impact of dishonest participants on the global outcome by 2(kα + BN), where represents the number of dishonest nodes using the sharing scheme.
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