Molecular dynamics has become a major tool in academic and industrial research in areas as varied as chemistry, biochemistry, physics and material science. For this reason there is a constant need for developments imp...
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ISBN:
(纸本)9781905088294
Molecular dynamics has become a major tool in academic and industrial research in areas as varied as chemistry, biochemistry, physics and material science. For this reason there is a constant need for developments improving the utilisation of supercomputer resources. The availability of such resources has raised the demand for access to longer time- and length-scales. On the one hand this has introduced new methodologies such as hyper-dynamics and meta-dynamics and on the other it has pushed development of softwareengineering and numerical methods to utilise resources more efficiently. An example of a software project that addresses such demands is DL_POLY_3. The code development has placed a particular emphasis on the efficient utilization of multi-processor power by optimised memory workload and distribution, which makes it possible to simulate systems of order of hundreds of millions of particles and beyond. In this paper we discuss the practical challenges to performance and scalability in research. These involve development of an efficient I/O scheme as the first step in accessing longer time- and length-scales. We also discuss the problems of tackling systems with highly non-uniform particle density distribution by spatial domain decomposition methods and outline a novel methodology that can load balance such systems.
Space and satellite systems are considered to be the most extreme environment to design for and are fraught with engineering difficulty. Performance metrics such as fault tolerance, reliability, pre-determinism and he...
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ISBN:
(纸本)9781424443277
Space and satellite systems are considered to be the most extreme environment to design for and are fraught with engineering difficulty. Performance metrics such as fault tolerance, reliability, pre-determinism and heritage are still high of the list of requirements for all missions. But with the advent of modern day electronics, greater computing capability and networking technologies have enabled research into distributed satellite systems, where multiple spacecraft work collaboratively to perform a mission. Leveraging from these technologies, a satellite can be considered one of many nodes in an autonomous system. This paper proposes the use of an Agent based computing platform to solve orbit dynamics problems leading to a highly mobile and decentralized system. The latest Agent platforms are compared and possible Agent applications are presented;specifically, distributed image compression and a novel topology reconfiguration scheme.
There are hundred of computers in a grid infrastructure and the proper operation of such large scale system depends on the security status of these computers. In order to increase the security level of the grid infras...
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ISBN:
(纸本)9781905088294
There are hundred of computers in a grid infrastructure and the proper operation of such large scale system depends on the security status of these computers. In order to increase the security level of the grid infrastructure a security assessment tool: Grid Site software Vulnerability Analyzer (GSSVA) has been designed and implemented by SZTAKI [1]. This developed monitoring tool overcomes the issues with communication through firewalls and client side installation without root privileges. GSSVA is using basic grid services, and can automatically explore the installed Linux packages locating on the grid machines. Our approach is extended with a modified PAKITI [2] status monitoring system, which can be re-used as a toolkit for further security parameter monitoring. In this paper we show the inner architecture of the developed GSSVA monitoring tool and assess its usability on the SEE-GRID-SCI [3] grid infrastructure.
This paper describes a study of the impact of communication behaviors on the performance of global software teams. Using a content analysis technique developed by [10], the researchers first characterized the asynchro...
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ISBN:
(纸本)9781424445851
This paper describes a study of the impact of communication behaviors on the performance of global software teams. Using a content analysis technique developed by [10], the researchers first characterized the asynchronous communications among student teams in Panama, Turkey and the US as they worked to complete a global software development project. Cluster analysis was then used to identify groups with similar communication patterns, which is defined as the proportion of time spent on each of the behaviors. Results suggest that particular patterns of communication behaviors are associated with higher performance. More specifically, it appears that communications related to the "contributing" category seem to have the strongest relationship to high performance.
Reliability has recently become an important issue in PC cluster technology. This research proposes a softwaredistributed shared memory system, named SCASH-FT, as an execution platform for high performance and highly...
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Recently, task allocation in multi-agent systems has been investigated by many researchers. Some researchers suggested to have a central controller which has a global view about the environment to allocate tasks. Alth...
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ISBN:
(纸本)9780769537474
Recently, task allocation in multi-agent systems has been investigated by many researchers. Some researchers suggested to have a central controller which has a global view about the environment to allocate tasks. Although centralized control brings convenience during task allocation processes, it also has some obvious weaknesses. Firstly, a central controller plays an important role in a multi-agent system, but task allocation procedures will break down if the central controller of a system cannot work properly. Secondly, centralized multi-agent architecture is not suitable for distributed working environments. In order to overcome some limitations caused by centralized control, some researchers proposed distributed task allocation protocols. They supposed that each agent has a limited local view about its direct linked neighbors, and can allocate tasks to its neighbors. However, only involving direct linked neighbors could limit resource origins, so that the task allocation efficiency will be greatly reduced. In this paper, we propose an efficient task allocation protocol for P2P multi-agent systems. This protocol allows not only neighboring agents but also indirect linked agents in the system to help with a task if needed. Through this way, agents can achieve more efficient and robust task allocations in loosely coupled distributed environments (e.g. P2P multi-agent systems). A set of experiments are presented in this paper to evaluate the efficiency and adaptability of the protocol. The experiment result shows that the protocol can work efficiently in different situations.
Event processing systems are a promising technology for enterprise-scale applications. However, achieving scalability yet maintaining high performance is a challenging problem. This work introduces a parallel matching...
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Self-stabilization is an elegant way of realizing non-masking fault-tolerant systems. Sustained research over last decades has produced multiple self-stabilizing algorithms for many problems in distributed computing. ...
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ISBN:
(纸本)9783642051173
Self-stabilization is an elegant way of realizing non-masking fault-tolerant systems. Sustained research over last decades has produced multiple self-stabilizing algorithms for many problems in distributed computing. In this paper, we present a framework to evaluate multiple self-stabilizing solutions under a fault model that allows intermittent transient faults. To that end, metrics to quantify the dependability of self-stabilizing systems are defined. It is also shown how to derive models that are suitable for probabilistic model checking in order to determine those dependability metrics. A heuristics-based method is presented to analyze counter examples returned by a probabilistic model checker in case the system under investigation does not exhibit the desired degree of dependability. Based on the analysis, the self-stabilizing algorithm is subsequently refined
The wide increase of total processing cores in commodity processors tends to lighten the need for computer performance by the classical scientific problems as well as by the modern multimedia and every day embedded ap...
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This paper describes a preliminary investigation of bibliographic citation practices in the field of computing, based on linguistic and rhetorical analyses of 1,255 citations in 36 academic papers from four representa...
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ISBN:
(纸本)9781424443574
This paper describes a preliminary investigation of bibliographic citation practices in the field of computing, based on linguistic and rhetorical analyses of 1,255 citations in 36 academic papers from four representative journals in the field: IEEE Transactions on softwareengineering, IEEE Transactions on Dependable and Secure Computing, IEEE Transactions on parallel and distributedsystems, and the IEEE Transactions on Computers. Rhetorical functions of the citations are identified, along with representative examples of the language that is used to achieve the rhetorical goals. The data is then discussed in light of current bibliographic citation instruction, and recommendations are made for developing better training for novices and normative speakers of English who need more specific than is normally available.
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