We have proposed and implemented a distributed asynchronous Web-based training (WBT) system. In order to improve the scalability and robustness of this system, all exercises and functions, such as scores user's an...
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ISBN:
(纸本)9780889867048
We have proposed and implemented a distributed asynchronous Web-based training (WBT) system. In order to improve the scalability and robustness of this system, all exercises and functions, such as scores user's answers are realized on mobile agents. these agents are distributed to computers, and they can be constructed with a P2P network that modified Content-Addressable Network (CAN). In this paper, we present the exercise management scheme for the proposed WBT system. In a WBT system based on client/server model, management of exercises is simply achieved by manipulating data, since all contents are concentrated in one server computer. In the proposed system, however, we need to pay attention to distributed agents for management of exercises. In order to achieve operation of exercise management, i.e., adding, deleting and updating exercises on the distributed WBT system, we use steps with considering multi-agent based distributed environment: specifying an agent which provides an exercise and searching its node as pre-operation, and sending an agent to the expected node and notifying other cooperating agents as post-operation.
distributedcomputing is becoming more and more led by technological and application advances. Many works consider new computing models compared to the classical closed model with a fixed number of participants and st...
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ISBN:
(纸本)9783642400476
distributedcomputing is becoming more and more led by technological and application advances. Many works consider new computing models compared to the classical closed model with a fixed number of participants and strong hypothesis on communication and structuration. Indeed, it is hard to imagine some application or computational activity and process that falls outside distributedcomputing. Internet and the web (e.g. social networks, clouds) are becoming the main application field for distributedcomputing. In addition to the classical challenges that developers have to face (asynchrony and failures) they have to deal with load balancing, malicious and selfish behaviors, mobility, heterogeneity and the dynamic nature of participating processes.
Both web services framework and peer-to-peer networks provide a discovery process, but as current P2P systems focus more on the discovery of content in the form of common files (possibly associated with metadata), a c...
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ISBN:
(纸本)9780889867048
Both web services framework and peer-to-peer networks provide a discovery process, but as current P2P systems focus more on the discovery of content in the form of common files (possibly associated with metadata), a centralized UDDI registry serves content in the form of metadata describing web services. thus, the intersection between P2P and Web services is clear, so that it recently gained lots of interest: there is the need of finding a way to exploit the high potential of web services without paying in terms of scalability or single-point-of-failures. Our aim in this paper is two-fold: on the one hand, we want to present a high level protocol for the addressing and the discovery of web services that is totally decentralized and based on a structured P2P topology. On the other hand, we introduce a way to solve the exact match key-based routing problem, that afflicts structured P2P systems. this model guarantees that all addressed web services will be discovered in a logarithmic number of hops, as it is based on a distributed Hash Table. One of the key innovation is the possibility of customizing the categorization of web services using tags, which are becoming very common in the so called Web 2.0.
Communication and agreement are fundamental abstractions in any distributed system. (If the computing entities do not need to communicate or agree in one way or another, the system is not a distributed system!) this t...
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the proceedings contain 25 papers. the topics discussed include: dependence-based code generation for a CELL processor;expression and loop libraries for high-performance code synthesis;applying code specialization to ...
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ISBN:
(纸本)3540725202
the proceedings contain 25 papers. the topics discussed include: dependence-based code generation for a CELL processor;expression and loop libraries for high-performance code synthesis;applying code specialization to FFT libraries for integral parameters;a characterization of shared data access patterns in UPC programs;on control signals for multi-dimensional time;an effective heuristic for simple offset assignment with variable coalescing;iterative compilation with kernel exploration;quantifying uncertainty in points-to relations;cache behavior modelling for codes involving banded matrices;tree-traversal orientation analysis;UTS: an unbalanced tree search benchmark;copy propagation optimizations for VLIW DSP processors withdistributed register files;optimal bitwise register allocation using integer linear programming;custom memory allocation for free;and runtime address space computation for SDSM systems.
Peer-to-peer (P2P) networking is designed for sharing resources at the edge of the Internet. Searching in file-sharing P2P networks has been an important research topic, and it has drawn significant attention recently...
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ISBN:
(纸本)9780889867048
Peer-to-peer (P2P) networking is designed for sharing resources at the edge of the Internet. Searching in file-sharing P2P networks has been an important research topic, and it has drawn significant attention recently. Hints can be utilized to improve query success rates. Determining how to efficiently and effectively propagate hints is a challenging issue. In this paper, we propose a searching protocol called HS-SDBF (Hint-based Search by Scope Decay Bloom Filter) that addresses this issue. HS-SDBF uses a data structure named SDBF (Scope Decay Bloom Filter) to represent and propagate probabilistic hints. Compared to existing proactive schemes, HS-SDBF can answer many more queries successfully at a lower amortized cost considering boththe query traffic and hint propagation traffic. the experimental results support the performance improvement of our protocol.
Nowadays, the disk storage's skyrocketing capacity has led to an amazing situation : grid-scale gathered storage of client nodes can overcome even the largest centralised storage units. thus, one of the key challe...
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ISBN:
(纸本)9780889867048
Nowadays, the disk storage's skyrocketing capacity has led to an amazing situation : grid-scale gathered storage of client nodes can overcome even the largest centralised storage units. thus, one of the key challenges related to the grid environment is to federate such spread storage resources together. thereby, we have developed Vis-ageFS, a Posix compliant, wide-area file system. It is mainly built upon a storage virtualization layer, plug-ins aware coherency layer and a multi-tiered administration and monitoring service. However, once featured with a global namespace fuelled by heterogeneous storage, the wide-area job scheduler is willing to be aware of data location. Furthermore, depending on workload, it may be highly desirable to make use of local storage facilities without data staging penalties. In this paper, we present one dynamic storage feature intended to provide transparent local storage access while remaining within the VisageFS global namespace.
Ensemble Kalman Filter (EnKF) uses a randomized ensemble of subsurface models for performance estimation. However, the complexity of geological models and the requirement of a large number of simulation runs make rout...
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ISBN:
(纸本)9780889867048
Ensemble Kalman Filter (EnKF) uses a randomized ensemble of subsurface models for performance estimation. However, the complexity of geological models and the requirement of a large number of simulation runs make routine applications extremely difficult due to expensive computation cost. Grid computing technologies provide a cost-efficient way to combine geographically distributedcomputing resources to solve large-scale data and computation intensive problems. We design and implement a grid-enabled EnKF solution to ill-posed model inversion problems for subsurface modeling. It has been integrated into the Res-Grid, a problem solving environment aimed at managing distributedcomputing resources and conducting subsurface-related modeling studies. Two use cases in reservoir studies indicate that the enhanced ResGrid efficiently performs EnKF inversions to obtain relatively accurate, uncertainty-ware predictions on reservoir production. this grid-enabled EnKF solution is also being applied for data assimilation of large-scale groundwater hydrology nonlinear models.
the proceedings contain 73 papers. the topics discussed include: alignment-based metrics for trace comparison;validation and uncertainty assessment of extreme-scale HPC simulation through Bayesian inference;energy-eff...
ISBN:
(纸本)9783642400469
the proceedings contain 73 papers. the topics discussed include: alignment-based metrics for trace comparison;validation and uncertainty assessment of extreme-scale HPC simulation through Bayesian inference;energy-efficient scheduling with time and processors eligibility restrictions;scheduling jobs with multiple non-uniform tasks;workflow fairness control on online and non-clairvoyant distributedcomputing platforms;how to be a successful thief: feudal work stealing for irregular divide-and-conquer applications on heterogeneous distributedsystems;scheduling HPC workflows for responsiveness and fairness with networking delays and inaccurate estimates of execution times;enhancing concurrency in distributed transactional memory through commutativity;adaptive granularity control in task parallel programs using multiversioning;and online dynamic dependence analysis for speculative polyhedral parallelization.
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