Centralized parallel packet switch algorithm and distributedparallel packet switch algorithm are two typical scheduling algorithms for parallel packet switch. this paper analyzes the two algorithms in detail, address...
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ISBN:
(纸本)9780769527369
Centralized parallel packet switch algorithm and distributedparallel packet switch algorithm are two typical scheduling algorithms for parallel packet switch. this paper analyzes the two algorithms in detail, addresses several key problems in their implementation and finally presents several available methods and suggestions to make the parallel packet switch more practical.
Modeling and testing for parallel software systems is difficult, because the number of states and execution fragments expand significantly caused by parallel behaviors, so that many traditional testing methods cannot ...
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ISBN:
(纸本)9780769548791
Modeling and testing for parallel software systems is difficult, because the number of states and execution fragments expand significantly caused by parallel behaviors, so that many traditional testing methods cannot work effectively for this kind of software. In this paper, a test sequence generation method based on model reduction for parallel software systems is shown. Firstly, a formal model for software system specification is constructed based on Coloured Petri Net (CPN), called system model;and a model reduction method based on trace-equivalent principle is shown and applied on system model, which could generate an external behavior equivalent model with smaller scale. Secondly, a linear behavior sequence of the system is specified using CPN, called LBS model, which represents testing purpose in a test case, and some operations between state space diagrams of system model and LBS model are defined, so that a sub-graph of system model state space diagram is generated, which could cover all executions of system model that involves behaviors of LBS. Finally, a performance analysis shows the effectiveness of the method.
this paper presents a ubiquitous computing technology called Virtual Personal computing Environment (VPCE), which enables users to access their personalized computing environments anywhere using any available terminal...
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ISBN:
(纸本)0769524052
this paper presents a ubiquitous computing technology called Virtual Personal computing Environment (VPCE), which enables users to access their personalized computing environments anywhere using any available terminals. the key feature of the VPCE is that it can be constructed dynamically by reassembling application services and resources distributed over networks, which is different from the traditional desktop personal computing environment that is tied to an individual computer to execute. In VPCE, users work with a heterogeneous collection of application services, and data access by application as well as the application accessed by users are distributed over networks, while the applications and data distribution is transparent to the users.
Barrier construct in OpenMP program is a directive used to remove race code before continuing. Each thread waits until all of the other threads of a team have reached the barrier region. And data dependence is a techn...
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ISBN:
(纸本)9780769536422
Barrier construct in OpenMP program is a directive used to remove race code before continuing. Each thread waits until all of the other threads of a team have reached the barrier region. And data dependence is a technology to find whether two statements can be run in parallel. this paper prevents two ways to optimize the OpenMP programa barrier. the first one is to remove redundant barrier with data dependence information, that is, if all the statements across a barrier have no data dependence, then the barrier can be safe v removed. And the second one is to reduce the cost of barrier. the paper gives an implementation of another form of parallelism- DOACROSS and a new form of OpenMP barrier-region barrier, in which both are synchronized with busy-waiting. Experimental results show that the performance of the optimized OpenMP program is improved.
Capabilities are a more scalable and adaptive access control approach compared withthe conventional approaches such as ACLs, due to their being held and managed by users or agents in systems, but not the middleware. ...
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ISBN:
(纸本)9780769548791
Capabilities are a more scalable and adaptive access control approach compared withthe conventional approaches such as ACLs, due to their being held and managed by users or agents in systems, but not the middleware. this feature makes capabilities more suitable in distributed environments that have dynamic populations. Treaties have been proposed to enhance the capability approach by introducing sequences of actions, such that treaties can capture characteristics of behaviours, and provide finer control over accesses. However there is a new problem brought by the behaviour modeling of treaties which is called duplication problem, which concerns preventing users from gaining unauthorised behaviour by duplicating treaties. In this paper we discuss this problem and propose three models of treaty systems that aim to solve the duplication problem.
Quality of Service (QoS) has now become a central issue in network design and application. this article describes a distributed architecture for linking geographically distributed network performance measurement and e...
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ISBN:
(纸本)0769524052
Quality of Service (QoS) has now become a central issue in network design and application. this article describes a distributed architecture for linking geographically distributed network performance measurement and evaluation system (NPMES) based on in-depth research on the key techniques of network QoS. the prototype implementation of NPMES and the performance evaluation criteria based on performance aggregation are carefully introduced Our contribution is presenting a new performance evaluation criteria based on performance aggregation to access QoS. Experiment results indicate the scalable NPMES can do the real-time detection on network performance of ISPs from the end user's perspective. the performance, aggregation approach is a bran-new idea, and of a definite practicability.
Online Analytical Processing (OLAP) is a critical component of data warehouse. Most of today's OLAP applications work on data warehouses with a centralized structure in which a single database contains huge amount...
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ISBN:
(纸本)0780378407
Online Analytical Processing (OLAP) is a critical component of data warehouse. Most of today's OLAP applications work on data warehouses with a centralized structure in which a single database contains huge amounts of data. A range query is a very popular and important operation on OLAP data cube in finding trends or relations between attributes. Methods of computing range query in a centralized data warehouse environment have been well studied. But to the best of our knowledge, there is no literature to date to discuss how to deal withthe range query in a PC cluster-based parallel data warehouse. In this paper, we present a parallel data cube storage structure, called parallel hierarchical data cube(PHDC). the analytical results show that PHDC may achieve better load-balance and optimum speed-up for range sum queries.
Word alignment is a basic task in natural language processing and it usually serves as the starting point when building a modern statistical machine translation system. However, the state-of-art parallel algorithm for...
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ISBN:
(纸本)9781509050819
Word alignment is a basic task in natural language processing and it usually serves as the starting point when building a modern statistical machine translation system. However, the state-of-art parallel algorithm for word alignment is still time-consuming. In this work, we explore a parallel implementation of word alignment algorithm on Graphics Processor Unit (GPU), which has been widely available in the field of high performance computing. We use the Compute Unified Device Architecture (CUDA) programming model to re-implement a state-of-the-art word alignment algorithm, called IBM Expectation-Maximization (EM) algorithm. A Tesla K40M card with 2880 cores is used for experiments and execution times obtained withthe proposed algorithm are compared with a sequential algorithm and a multi-threads algorithm on an IBM X3850 server, which has two Intel Xeon E7 CPUs (2.0GHz * 10 cores). the best experimental results show a 16.8-fold speedup compared to the multi-threads algorithm and a 234.7-fold speedup compared to the sequential algorithm.
the molecular docking is the focus of practical applications such as protein engineering and drug design. A docking algorithm is a procedure that predicts the assembly of two molecules like a key and a lock. To screen...
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ISBN:
(纸本)9781467316583
the molecular docking is the focus of practical applications such as protein engineering and drug design. A docking algorithm is a procedure that predicts the assembly of two molecules like a key and a lock. To screen a large library of molecules, a docking algorithm requires high performance computing. parallel and distributedapplications have long been recognized as powerful computational tools and effective in the field of bioinformatics. Jini technology is one of the powerful infrastructures network for building and deploying distributed systems that are organized as a federation of services. JavaSpaces is one of the services that come bundled with Jini, it is a shared associative memory accessible by the network and allows an easily developing of a massively parallel and distributedapplications. this paper discusses the use of the JavaSpaces service to build a distributed application in order to minimize the running time of a molecular docking algorithm.
Cloud computing is one of the most popular technologies nowadays because of its wide utilities and various benefits in several IT companies all over the world. However, in front of the increasing users' requests f...
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ISBN:
(纸本)9781538637906
Cloud computing is one of the most popular technologies nowadays because of its wide utilities and various benefits in several IT companies all over the world. However, in front of the increasing users' requests for computing services, cloud providers are encouraged to deploy large data centers, which consumes very large amount of energy and contribute to high operational costs. Among the effects, carbon dioxide emission rate is growing each day due to the huge amount of power consumption. this energy efficiency is an important issue in cloud computing, mainly due to the required electrical power to run these systems and to cool them. therefore, energy consumption has become a major concern for the widespread deployment of Cloud data centers. the growing importance for parallelapplications in the Cloud introduces significant challenges in reducing energy consumption from hosted servers. this paper addresses the problem of placing independent applications on the physical servers (hosts) of a Cloud infrastructure. We proposed a novel heuristic to allocate applications so that total energy consumption is reduced. Our proposal respects various constraints e.g. the machines availability, capability and the duplication of applications. Experiments are illustrated to validate the potential of our approach.
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