A Tool for Programming Embarrassingly Task Parallel Applications on CoW and NoW

Embarrassingly parallel problems can be split in parts that are characterized by a really low (or sometime absent) exchange of information during their computation in parallel. As a consequence they can be effectively computed in parallel exploiting commodity hardware, hence without particularly sophisticated interconnection networks. Basically, this means Clusters, Networks of Workstations and Desktops as well as Computational Clouds. Despite the simplicity of this computational model, it can be exploited to compute a quite large range of problems. This paper describes JJPF, a tool for developing task parallel applications based on Java and Jini that showed to be an effective and efficient solution in environment like Clusters and Networks of Workstations and Desktops.Comment: 7 page

GENESIS: A System for Simulating Neural Networks

We have developed a graphically oriented, general purpose simulation system to facilitate the modeling of neural networks. The simulator is implemented under UNIX and X-windows and is designed to support simulations at many levels of detail. Specifically, it is intended for use in both applied network modeling and in the simulation of detailed, realistic, biologically-based models. Examples of current models developed under this system include mammalian olfactory bulb and cortex, invertebrate central pattern generators, as well as more abstract connectionist simulations

Distributed Linear Algebra on Networks of Workstations

This thesis describes the development of a portion of a distributed linear algebra library for use on networks of workstations. The library was designed with special consideration towards three characterists of networks of workstations: small numbers of processes, availability of multithreading, and high communication latency. Two aspects of the library are highlighted. First, modifications to message passing primitives to permit their use in a multithreaded environment. Second, modifications to basic linear algebra algorithms to improve their performance on networks of stations. A model of distributed linear algebra on networks of workstations is developed, and used to predict the performance of the modified algorithms. These predictions are compared to experimental results on several networks of workstations

Improved algorithms for machine allocation in manufacturing systems

In this paper we present two algorithms for a machine allocation problem occurring in manufacturing systems. For thetwo algorithms presented we prove worst-case performance ratios of 2 and 312, respectively. The machlne allocat~onproblem we consider is a general convex resource allocation problem, which makes the algorithms applicable to a varletyof resource allocation problems. Numerical results are presented for two real-life manufacturing systems.networks;manufacturing;allocation of machines;performance/productivity;queues

Performance of scientific processing in networks of workstations: matrix multiplication example

Parallel computing on networks of workstations are intensively used in some application areas such as linear algebra operations. Topics such as processing as well as communication hardware heterogeneity are considered solved by the use of parallel processing libraries, but experimentation about performance under these circumstances seems to be necessary. Also, installed networks of workstations are specially attractive due to its extremely low cost for parallel processing as well as its great availability given the number of installed local area networks. The performance of such networks of workstations is fully analyzed by means of a simple application: matrix multiplication. A parallel algorithm is proposed for matrix multiplication derived from two main sources: a) previous proposed algorithms for this task in traditional parallel computers, and b) the bus based interconnection network of workstations. This parallel algorithm is analyzed experimentally in terms of workstations workload and data communication, two main factors in overall parallel computing performance

Document Archiving, Replication and Migration Container for Mobile Web Users

With the increasing use of mobile workstations for a wide variety of tasks and associated information needs, and with many variations of available networks, access to data becomes a prime consideration. This paper discusses issues of workstation mobility and proposes a solution wherein the data structures are accessed in an encapsulated form - through the Portable File System (PFS) wrapper. The paper discusses an implementation of the Portable File System, highlighting the architecture and commenting upon performance of an experimental system. Although investigations have been focused upon mobile access of WWW documents, this technique could be applied to any mobile data access situation.Comment: 5 page

Modeling a healthcare system as a queueing network:The case of a Belgian hospital.

The performance of health care systems in terms of patient flow times and utilization of critical resources can be assessed through queueing and simulation models. We model the orthopaedic department of the Middelheim hospital (Antwerpen, Belgium) focusing on the impact of outages (preemptive and nonpreemptive outages) on the effective utilization of resources and on the flowtime of patients. Several queueing network solution procedures are developed such as the decomposition and Brownian motion approaches. Simulation is used as a validation tool. We present new approaches to model outages. The model offers a valuable tool to study the trade-off between the capacity structure, sources of variability and patient flow times.Belgium; Brownian motion; Capacity management; Decomposition; Health care; Healthcare; Impact; Model; Models; Performance; Performance measurement; Queueing; Queueing theory; Simulation; Stochastic processes; Structure; Studies; Systems; Time; Tool; Validation; Variability;

Performance of scientific processing in networks of workstations: matrix multiplication example

Parallel computing on networks of workstations are intensively used in some application areas such as linear algebra operations. Topics such as processing as well as communication hardware heterogeneity are considered solved by the use of parallel processing libraries, but experimentation about performance under these circumstances seems to be necessary. Also, installed networks of workstations are specially attractive due to its extremely low cost for parallel processing as well as its great availability given the number of installed local area networks. The performance of such networks of workstations is fully analyzed by means of a simple application: matrix multiplication. A parallel algorithm is proposed for matrix multiplication derived from two main sources: a) previous proposed algorithms for this task in traditional parallel computers, and b) the bus based interconnection network of workstations. This parallel algorithm is analyzed experimentally in terms of workstations workload and data communication, two main factors in overall parallel computing performance.Facultad de Informátic