Probabilistic occupancy grids have proved to be very useful for workspace modeling in 2D environments. Due to the expansion of computational load, this approach was not tractable for mapping a 3D environment in real a...
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Probabilistic occupancy grids have proved to be very useful for workspace modeling in 2D environments. Due to the expansion of computational load, this approach was not tractable for mapping a 3D environment in real applications. In this paper, the original occupancy grid scheme is revisited and a generic closed-form function is introduced to avoid numerical computation of probabilities for a range sensor with Gaussian error distribution. Occupancy probabilities are computed and stored in a multiresolution octree for improved performance and compactness. Occupancy models are built in local reference frames and linked to a global reference frame through uncertain spatial relationships that can be updated dynamically. This scheme is used for building a 3D map in a telerobotic maintenance application of electric power lines where perturbations may cause motion of object assembly.
A programming model that is widely approved today for large applications is parallel programming with shared variables. We propose an implementation of shared arrays on distributed memory architectures: it provides th...
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ISBN:
(纸本)0818675578
A programming model that is widely approved today for large applications is parallel programming with shared variables. We propose an implementation of shared arrays on distributed memory architectures: it provides the user with an uniform addressing scheme while being efficient thanks to a logical paging technique and optimized communication mechanisms.
The total and causal ordering of group operations in distributedsystems is at the core of solutions to many problems in distributedcomputing. Existing approaches are based on either a centralized coordinator to assi...
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The total and causal ordering of group operations in distributedsystems is at the core of solutions to many problems in distributedcomputing. Existing approaches are based on either a centralized coordinator to assign a sequence number for each operation or on a distributed two-phase protocol to determine the total ordering number. This paper proposes an efficient distributed single-phase protocol which determines the total ordering of group operations at the moment when operations are generated, without the need for a dedicated phase of determining the total ordering.
We present an efficient connection caching scheme in a distributed system where we divide the system into several host groups possibly overlapping and the connection between the hosts in the same group is kept prior t...
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ISBN:
(纸本)0818675578
We present an efficient connection caching scheme in a distributed system where we divide the system into several host groups possibly overlapping and the connection between the hosts in the same group is kept prior to others. Every host group consists of hosts which have heavy intercommunication. We present performance evaluation of the proposed connection caching scheme in several aspects including group size, grouping and types of the group. Simulation results show that host grouping is effective in every performance criterion and that proper grouping of hosts enhances the performance. We also present a simple Markov process model of our scheme and give some analysis results which are consistent with the simulation results.
PARallel and distributedcomputing (PArdISC) is a parallel programming environment which provides the needed transparency as a scalable OpenFrame computing Model. It can be used to configure the network as a loosely c...
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PARallel and distributedcomputing (PArdISC) is a parallel programming environment which provides the needed transparency as a scalable OpenFrame computing Model. It can be used to configure the network as a loosely coupled parallel machine, processor pool architecture, and distributedcomputing environment with Logical Network Connectivity. The software architecture of PArdISC is made up of configuration servers, client processes, processor pool servers and process communication interface.
The computing resources offered by a collection of workstations can be enormous. To locate and utilize idle workstations efficiently has been a problem requiring much study. A process migration facility is one such me...
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ISBN:
(纸本)0818675578
The computing resources offered by a collection of workstations can be enormous. To locate and utilize idle workstations efficiently has been a problem requiring much study. A process migration facility is one such method aimed at better utilization of the vast computing potential that allows the user of a workstation to off-load programs onto idle workstations, thereby providing the user with access to computational resources far beyond that provided by his or her personal workstation. PMDOS: Process Migration on a network of DOS workstations -A distributed processing system comprising a checkpoint/restart mechanism and a process migration mechanism at user level was designed and implemented on a network of DOS machines (PC's) to create an environment wherein: temporarily unused workstations can be accessed by other users on the network to perform distributed or parallel computations or execute background or non-interactive jobs. An owner of a workstation need not be aware that the machine is being used during idle times;the machine is immediately returned when the owner begins to work again. The system gives good throughput, fault tolerance and efficiency for parallel and distributed applications.
In this paper, three main parts of BAG real-time distributed operating system are introduced: task migration, load balancing and distributed file system. Task migration, based on EFSM programming model, is implemented...
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In this paper, three main parts of BAG real-time distributed operating system are introduced: task migration, load balancing and distributed file system. Task migration, based on EFSM programming model, is implemented as a means of load balancing mechanism. A file system supporting the task migration mechanism is also designed and developed.
The proceedings contains 74 papers from the 3rdinternationalconference on High Performance computing. Topics discussed include: genetic algorithms, optical computers, parallel webservers, direct circuit simulation, ...
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The proceedings contains 74 papers from the 3rdinternationalconference on High Performance computing. Topics discussed include: genetic algorithms, optical computers, parallel webservers, direct circuit simulation, character recognition, multimedia servers, the RAID configuration tool, concurrent call/return communication, parallel processing systems, real-time distributed operating systems, database systems, mobile computers, binary trees, close wormhole networks, program analysis, data-flow analysis, reduced instruction set computing (RISC), and edge extraction.
Consistent recovery from process failures is an essential component of reliable distributedsystems. Many existing recovery techniques use asynchronous message logging and checkpoints. Most of the present approaches d...
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Consistent recovery from process failures is an essential component of reliable distributedsystems. Many existing recovery techniques use asynchronous message logging and checkpoints. Most of the present approaches depend on logged states of non-fail processes for recovery. A model of recovery based on the current active states of processes has been proposed. The algorithm considers recoverable state of the failed process and current states of the non-failed processes. Each process recovers to a consistent system state independently.
DiET provides a framework to experiment with extended transaction models and also to synthesize new models. As case studies nested and split-join transaction types have been implemented. DiET is a framework loosely co...
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DiET provides a framework to experiment with extended transaction models and also to synthesize new models. As case studies nested and split-join transaction types have been implemented. DiET is a framework loosely coupled with a distributed storage manager and PVM. Such a coupling enables DiET to cope up with a wide variety of storage manager and distributed process manager without any difficulty. The performance measures indicate high speedup for complex applications.
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