Between 1987 and 1994, more than 100 students in a broad range of disciplines worked as summer scholars at Edinburgh parallelcomputingcentre. Many of these students have since taken their parallelcomputing skills i...
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(纸本)9780818666056
Between 1987 and 1994, more than 100 students in a broad range of disciplines worked as summer scholars at Edinburgh parallelcomputingcentre. Many of these students have since taken their parallelcomputing skills into graduate work and industry, and over a quarter of EPCC's technical staff are alumni of the Programme. This report describes the evolution and present operation of the Summer Scholarship Programme, and its costs and benefits.< >
The lack of a portable programming interface for parallel computers has inhibited the development of applications for such systems, and thus restricted the exploitation of this technology. In this paper we discuss var...
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The lack of a portable programming interface for parallel computers has inhibited the development of applications for such systems, and thus restricted the exploitation of this technology. In this paper we discuss various efforts to provide a portable interface to parallel computers, and present the Edinburgh CHIMP (Common High-level Interface to Message-Passing), and PUL (parallel Utilities Library) activities in this context. The concepts behind these projects are described, with details of the range of parallel systems on which they are available. An important consequence of the portability offered by the CHIMP message passing layer is the ability for applications programmers to reuse entire programs, as well as code modules. PUL assists this by providing a set of reusable components for implementing parallel applications. Developed on top of CHIMP, the PUL utilities are themselves portable across a range of platforms. Finally, this paper summarises experience using CHIMP and PUL to implement parallel applications in collaboration with both industrial and academic groups.
The paper describes the design of a distributed software architecture for an intelligent planning system based on a process model of cognitive systems (PMCS). PMCS is described in terms of its problem-solving behaviou...
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The paper describes the design of a distributed software architecture for an intelligent planning system based on a process model of cognitive systems (PMCS). PMCS is described in terms of its problem-solving behaviour and structure, and is illustrated through a simple case study in robotics. In the PMCS autonomous knowledge sources, implementing a component of the functionality, co-operate by message-passing in order to maintain a distributed model of the system's environment and to synthesise decisions based on the model. Simulation tools developed at the University of Westminster for the rapid prototyping of parallel systems have been used to simulate the software architecture based on PMCS. Simulation results for the planning case study are presented in order to demonstrate the effectiveness of PMCS in solving planning problems in a distributed manner.
Transformer models have become a cornerstone of various natural language processing (NLP) tasks. However, the substantial computational overhead during the inference remains a significant challenge, limiting their dep...
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The total energy pseudopotential method is well suited to parallel processing. This paper discusses a procedure for calculating the valence electronic wavefunction in a given ionic configuration, and considers the exp...
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The total energy pseudopotential method is well suited to parallel processing. This paper discusses a procedure for calculating the valence electronic wavefunction in a given ionic configuration, and considers the exploitation of parallel processing using a data parallel approach. The implementation of this procedure on two message passing i860 based machines, containing up to 64 nodes, is described, and the prospects for massively parallel execution are examined.
The leaching of a mineral from the ground is considered using injection and recovery holes drilled into the rock. In this simplified analysis, the holes are arranged vertically and an appropriate caustic leaching flui...
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The leaching of a mineral from the ground is considered using injection and recovery holes drilled into the rock. In this simplified analysis, the holes are arranged vertically and an appropriate caustic leaching fluid is introduced into the uppermost hole. The leaching liquor percolates down through the rock, dissolving the mineral of interest, and is pumped out when it arrives at the second hole. Water is introduced at the bottom hole in an attempt to increase the feasible recovery fraction of mineral-bearing liquor. Tire model problem is solved numerically using a boundary-integral formulation. Maximum feasible recovery fractions for the leaching fluid are obtained and their dependence upon the separation distance between the injection and recovery points and upon the pumping rate for water at the bottom hole are studied The volume of rock inundated by the leaching liquor is assessed, and a possible practical strategy for in situ leaching of low-grade ores is proposed.
Steady, two-dimensional, two-layer flow over an arbitrary topography is considered. The fluid in each layer is assumed to be inviscid and incompressible and flows irrotationally. The interfacial surface is found using...
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Steady, two-dimensional, two-layer flow over an arbitrary topography is considered. The fluid in each layer is assumed to be inviscid and incompressible and flows irrotationally. The interfacial surface is found using a boundary integral formulation, and the resulting integrodifferential equations are solved iteratively using Newton's method. A linear theory is presented for a given topography and the non-linear theory is compared against this to show how the non-linearity affects the problem.
Prospecting for oil and gas resources poses the problem of determining the geological structure of the earth's crust from indirect measurements. Seismic migration is an acoustic image reconstruction technique base...
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Prospecting for oil and gas resources poses the problem of determining the geological structure of the earth's crust from indirect measurements. Seismic migration is an acoustic image reconstruction technique based on the inversion of the scalar wave equation. Extensive computation is necessary before reliable information can be extracted from large sets of recorded data. In this paper a collection of ''industrial'' migration techniques, each giving rise to a data parallel algorithm, is outlined. Computer simulations on synthetic seismic data illustrate the problem and the approach.
Forced motion of a spherical bubble in an incompressible viscous fluid is considered. The system is assumed to be governed by the Rayleigh-Plesset equation, and the forcing occurs by means of a harmonically varying pr...
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Forced motion of a spherical bubble in an incompressible viscous fluid is considered. The system is assumed to be governed by the Rayleigh-Plesset equation, and the forcing occurs by means of a harmonically varying pressure field at infinity. A perturbation solution is presented, which extends previously published results in that it gives a complete qualitative description of the behaviour near the primary resonance, as well as for all the superharmonic and subharmonic resonances. These low order results are confirmed and extended to large amplitude motion by means of a numerical shooting algorithm. The method is capable of computing stable and unstable periodic solutions with equal ease, and it determines the stability automatically by using a numerical implementation of Floquet theory. The application of this numerical method to a non-analytical model of bubble behaviour is briefly discussed.
This paper presents a deadlock-free routeing algorithm for multiprocessor interconnection networks based on store-and-forward (S/F) communication. The adaptive nature of the method proposed encourages using light traf...
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This paper presents a deadlock-free routeing algorithm for multiprocessor interconnection networks based on store-and-forward (S/F) communication. The adaptive nature of the method proposed encourages using light traffic paths. Furthermore it has the properties of avoiding blocked communication (deadlock), reducing communication delay time between source and destination, using efficiently message buffers as network resources and being able to control communication traffic flow from each processor of the network. The routeing algorithm has been implemented on a 64-node transputer network (T-Rack) configured as a number of well known topologies to evaluate the behaviour of the algorithm and some performance figures have been derived.
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