CORBA is becoming the most important middleware that supports object oriented and client/server paradigm in distributedcomputing systems. However the application systems based on CORBA are still scarce to date. One m...
详细信息
ISBN:
(纸本)0818686030
CORBA is becoming the most important middleware that supports object oriented and client/server paradigm in distributedcomputing systems. However the application systems based on CORBA are still scarce to date. One main reason is that only few CORBA object services have been developed. Without added help mechanisms, to have a new CORBA application, a programmer should make efforts to design a program with a CORBA interface from scratch. In our previous work (K. Liang et al., 1997), a reengineering approach was proposed to convert RPC based programs to CORBA objects, which successfully speeded up the development of CORBA applications. However the source code is required in this approach. In many cases, software designers may not be able to get hold of the source code, so it is necessary to adapt existing PC software applications, particularly for Windows applications, in binary code mode to the object services under CORBA. Our study addresses this problem. A graphic factory temperature monitor system, which integrates MS-Excel under MS-Windows has been implemented to demonstrate the feasibility of our approach.
As technological advances are made in software and hardware, the feasibility of accessing information "anytime, anywhere" is becoming a reality. There are similarities involved in accessing information in a ...
详细信息
As technological advances are made in software and hardware, the feasibility of accessing information "anytime, anywhere" is becoming a reality. There are similarities involved in accessing information in a multidatabase environment and a mobile computing environment. We have discussed the characteristics of a wireless-mobile computing environment superimposed on a multidatabase system to realize a system capable of effectively accessing a large amount of data over a wireless medium. In order to limit the effects of the restrictions imposed by a mobile environment, data duplication is used at the mobile unit. The duplicated data at the mobile node provide additional availability in case of a weak connection or disconnection. In such an environment, it is important to retain the consistency between the data residing on fixed nodes and mobile nodes. Current research has concentrated on page- and file-based caching or replication schemes to address the availability and consistency issues in a mobile environment. In a mobile multidatabase environment, local autonomy restrictions prevent the use of a page- or file-based data duplication scheme. We propose a new data duplication scheme to address the limited bandwidth and local autonomy restrictions in such an environment. Queries and their associated data are cached at the mobile unit as a complete object. Consistency is maintained by using a parity-based invalidation scheme. Additionally, a simple prefetching scheme is used in conjunction with caching to further improve effectiveness of the proposed scheme.
General Circulation Models (GCMs) are at the top of the hierarchy of numerical models that are used to study the Earth's climate. To increase the significance of predictions using GCMs requires ensembles of integr...
详细信息
ISBN:
(纸本)9780897919845
General Circulation Models (GCMs) are at the top of the hierarchy of numerical models that are used to study the Earth's climate. To increase the significance of predictions using GCMs requires ensembles of integrations that in turn demand large amounts of computing resources. GCMs codes are particularly difficult to optimize in view of their heterogeneity. In this paper we focus on code optimization for GCMs of the atmosphere (AGCMs), one of the major components of the climate *** this paper, we present our efforts in optimizing the parallel UCLA AGCM code. The UCLA AGCM is a state-of-the-art finite-difference model of the global atmosphere. Our optimization efforts include the implementation of load balancing schemes, new physical parameterizations of atmospheric processes, code restructuring and use of special mathematical functions. At the beginning of this work, the overall execution time of the code was 459 seconds per simulated day in 256 nodes of a CRAY T3D. At present, the same model configuration requires 51 seconds per simulated day in 256 nodes of a CRAY T3E-900, which is approximately 9 times faster. The peak model performance is about 40 GFLOPs on 512 T3E-900 nodes. We present results in support of our conclusion that major advances in our ability to carry out longer and more detailed climate simulations depend primarily upon development of more powerful supercomputers and that code optimization, for a particular computer architecture, and development of more efficient algorithms can be nearly as important.
A parallel design and implementation of the Self-Organizing Map (SOM) neural computing model is proposed. The parallel design of SOM is implemented in a parallel virtual machine (PVM) environment of a distributed syst...
详细信息
A parallel design and implementation of the Self-Organizing Map (SOM) neural computing model is proposed. The parallel design of SOM is implemented in a parallel virtual machine (PVM) environment of a distributed system. A practical realization of SOM algorithm is investigated, the construction of computing module in parallel virtual machine is discussed, the communication methods and an optimization of messages passing between multiple processes are proposed, and the parallel programming technique and a PVM implementation of SOM neural computing model are given and discussed in detail.
Neural system, as processors of time-sequence patterns, have been successfully applied to several speaker-dependent speech recognition computing. They can be efficiently implemented by a pipeline architecture. In this...
详细信息
Neural system, as processors of time-sequence patterns, have been successfully applied to several speaker-dependent speech recognition computing. They can be efficiently implemented by a pipeline architecture. In this paper, a parallel time-delay speech recognition computing for VLSI neural systems is presented. The system design methodology is to emphasize a coordination between computational model, architectural description, and VLSI systolic implementation. Examples of time-delay speech recognition applications to VLSI neural system design and performance analysis are given to illustrate effectiveness of the parallel computation.
An effective automatic parallelizer is critical for users to exploit the resources of parallel computers. Researcher has gained much progress in recent years. This paper introduces AFT, a new generation parallelizing ...
详细信息
An effective automatic parallelizer is critical for users to exploit the resources of parallel computers. Researcher has gained much progress in recent years. This paper introduces AFT, a new generation parallelizing compiler that we developed. It integrates many advanced techniques in an effective and efficient system. The experiment result shows that AFT is able to achieve notable parallelization on many programs.
In this work, it is argued that because of recent advance of network & CPU technologies, workstation clusters are poised to become the primary parallelcomputing infrastructure for science and engineering computin...
详细信息
In this work, it is argued that because of recent advance of network & CPU technologies, workstation clusters are poised to become the primary parallelcomputing infrastructure for science and engineering computing. After analyzing and comparing the communication performance of three popular networks: 10Mbps Ethernet, 100Mbps Ethernet and 640Mbps Myrinet on an experimental workstation cluster, it is pointed that two main factors hinder the wider application of workstation cluster. These problems are overcome by implementing two workstation cluster systems for different performance/price rate requirements.
In this paper, we present an original approach for the design and execution of distributed applications that require numerous tasks of variable grain. The approach is based on the concept of task cluster which is an e...
详细信息
In this paper, we present an original approach for the design and execution of distributed applications that require numerous tasks of variable grain. The approach is based on the concept of task cluster which is an entity that groups tasks with strong logical interaction and that guarantees efficient communications between them. We describe the implementation of the model, that mainly relies on the use of lightweight processes as support for the distributed tasks. We also illustrates the use of the proposed approach on real size applications where it has improved both the ease of design and the performance.
This paper presents the coherent parallel programming concept using a new parallel language called C (pronounced C parallel). The language is based on the standard C language with a small set of extended constructs fo...
详细信息
This paper presents the coherent parallel programming concept using a new parallel language called C (pronounced C parallel). The language is based on the standard C language with a small set of extended constructs for parallelism and process interaction. At the core of C is a structured construct called coherent region, which facilitates the development of coherent programs, i.e., parallel programs that are structured, determinate, terminative, and compositional. We present the basic features of C and show that coherent region is a versatile construct.
This paper surveys the program dependence analysis technique for parallel and/or distributed programs and its applications from the viewpoint of software engineering. We present primary program dependences which may e...
详细信息
ISBN:
(纸本)0818678763
This paper surveys the program dependence analysis technique for parallel and/or distributed programs and its applications from the viewpoint of software engineering. We present primary program dependences which may exist in a parallel and/or distributed program, a general approach to define, analyze, and represent these program dependences formally, and applications of an explicit program dependence based representation for parallel and/or distributed programs in various software engineering activities. We also suggest some research problems on this direction.
暂无评论