IMPLEMENTATION OF A LINEAR QUADTREE CODING SCHEME ON THE PARALLEL VIRTUAL MACHINE

This paper discusses the design of a hybrid artificial neural network (ANN) system and its implementation in the Parallel Virtual Machine (PVM) environment. First, the PVM functions for supporting parallel applications and communications among multiple processes and multiple machines are investigated. Then, the design and construction of a hybrid ANN simulation software is proposed. It includes the user interface, control and SPMD computing levels. The software can be used for supporting parallel simulation of different kinds of learning algorithms and neural computing models.

The Parallel Virtual Machine (PVM) system is a software framework that enables heterogeneous concurrent computing in heterogeneous environments. Since its conception in 1989, it has evolved into a very popular and widely used platform for cluster and network computing. The programming model supported by PVM, straightforward formulation of the API, robust portable implementations, and timeliness have all played an important role in PVM's impact on high performance computing. We discuss the overall design of PVM and describe its ongoing evolution, recently introduced features, and future directions.KeywordsVirtual MachineMessage PassingRemote Procedure CallCommunication VolumeParallel Virtual MachineThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Heterogeneous Network-Based Concurrent Computing Systems

For many large scientific applications, computing on a cluster is a viable, economical alternative to a dedicated parallel machine. Application performance on a cluster is largely determined by the speed of the underlying communication network. The authors use a parallel network approach to improve the communication network performance. More specifically, they use multiple networks based on Ethernet to improve the performance. The authors modified the parallel virtual machine (PVM) environment to take advantage of multiple Ethernets by using round robin scheduling strategy. The modified PVM, referred as PPVM, showed an improvement of 35% over PVM under no background load, and an improvement of 100% under background load on two channels. >

MATLAB Distributed Computing Server (MDCS) and Parallel Virtual Machine (PVM) software are two types of distributed computing environments. MDCS is recently used in selecting the best network training algorithm and assessing the effect of parallelization. Since it is practical and user friendly, it gives PVM the opportunity to become the communication paradigm of choice. The PVM provides a powerful set of process control and dynamic resource management features. In the distributed parallel computing (DPC), however, both solutions have different strengths and limitations. Based on these concerns, this paper compares the numerical analysis for mathematical modeling of large sparse 2D and 3D of second order parabolic partial differential equations (PDE) on MDCS and PVM based on parallel performance indicators (PPI). The PDE geometry is discretized into a sparse grid structure using the FDM method. In using a method with the highest accuracy, Parallel Alternating Group Explicit (PAGE) scheme was chosen. The parallel strategies focus on the PAGE's convergence speed and various domain de-composition techniques, as well as a block iterative scheme and load balance using fine granular techniques. Furthermore, comparison of distributed computing environments also relies on multiple processors running on Unix-like operating systems with Fedora installed to support large-scale simulations. The analysis and validation of PPI for both communication software is also investigated in this paper. For a sequential algorithm, accuracy, estimation of error, and stability are employed as indicators. As a conclusion, based on the PPI and numerical analysis, the tables and graphs show that compared to MDCS, PVM is a better environment for solving multidimensional parabolic PDE modeling.KeywordsDistributed computingParabolic PDEsMDCSPVM

Implementation of a parallel Genetic Algorithm on a cluster of workstations: Traveling Salesman Problem, a case study

The JPVM library is a software system for explicit message-passing based distributed memory MIMD parallel programming in Java. The library supports an interface similar to the C and Fortran interface provided by the Parallel Virtual Machine (PVM) system, but with syntax and semantics modifications afforded by Java and better matched to Java programming styles. The similarity between JPVM and the widely used PVM system supports a quick learning curve for experienced PVM programmers, thus making the JPVM system an accessible, low-investment target for migrating parallel applications to the Java platform. At the same time, JPVM offers novel features not found in standard PVM such as thread safety, multiple communication end-points per task, and default-case direct message routing. JPVM is implemented entirely in Java, and is thus highly portable among platforms supporting some version of the Java Virtual Machine. This feature opens up the possibility of utilizing resources commonly excluded from network parallel computing systems such as Macintosh and Windows-NT based systems. Initial applications performance results achieved with a prototype JPVM system indicate that the Java-implemented approach can offer good performance at appropriately coarse granularities.

Parallel implementation of 2D LGA and MD simulations

Tissue analysis is essential for dealing with a number of problems in cancer research. This research tries to address the problem of identifying normal, dysplastic and cancerous colonic mucosa by means of Texture analysis techniques. A genetic algorithm is used to interpret the results of those operations. Image- processing operations and genetic algorithms are both tasks requiring vast processing power. PVM (Parallel Virtual Machine), a message-passing library for distributed programming has been selected for implementing a parallel classification system. To further enhance PVM functionality a C++ object-oriented “PVM wrapper” was constructed.

We show the implementation and the simulation results of a hierarchical, cluster based routing protocol for mobile ad hoc networks using Parallel Virtual Machine (PVM). The network represented by a graph is partitioned into clusters by a graph partitioning algorithm and the shortest routes are first calculated locally in each cluster in the first srep. The simplified network which consists only of the nodes that have connections to other clusters called the neighbor nodes is then formed and the shortest routes are calculated for this simple network as the second step. A complete route between the two nodes of different clusters is formed by the union of intra-cluster and inter-cluster routes. We show the implementation results using PVM where a workstation represents a cluster and each node is a PVM process. The results obtained support the theoretical considerations where the efficiency increases by the number of clusters in use.

Parallel PCG Algorithm On Distributed Network By PVM

Parallel implementing OpenGL on PVM

A parallel unstructured mesh generation technique is proposed based on the built-in cyber-physical system (CPS) of Parallel Virtual Machine context. A static load-balancing strategy for computational domain decomposition is firstly presented in the paper. After dividing the whole computational domain into several sub-domains, unstructured grids are separately generated in each sub-domain using the advancing-front grid generation technique. Besides, for a dynamic load-balancing strategy, Lohner’s advancing front domain-splitting algorithm is improved to make the sub-grids and their boundaries more favorable for the grid generation. Moreover, a new optimization strategy of sub-domain’s boundary is simultaneously presented to smooth the boundaries and improve the quality of grids. Finally, conditions of receiving new points and elements are also developed during the grid generation in the sub-domain. Meanwhile, a new strategy of receiving new elements and refusing new points during the interface grid generation is proposed, which can save computational cost. A new parallel Laplacian smoother technique is implemented to generate high-quality mesh. Meshes for NACA0012 airfoil, cylinder, and multi-element airfoil are generated by the improved parallel algorithm using the static and dynamic load-balancing strategies. Some comparisons of parallel calculations are also made using the different number of processors in the tables.

The author presents the architecture of a new family of parallel operating systems based on an alternative design approach when compared to multiprogramming, namely, generic construction of parallel virtual machines. This construction is made according to needs of models for parallel programming which shall be supported as subsystems by the parallel operating system kernel. The author presents the PAROS architecture and its generic kernel ParX which has been designed for message passing parallel computers. Several parallel virtual machines are also described, such as for instance a diffusion virtual machine, and a message passing-shared data virtual machine. >

When photovoltaic inverters operate in parallel, the output of each inverter’s impedance and the line impedance of aren’t consistent, resulting in the instantaneous voltage of each inverter at the common parallel point is not equal, so in the parallel inverters system, the circulating current is easy to form between each inverter, which affects the distribution of active power together with reactive power. In this paper, feedforward compensation is leaded-in active and reactive power control channels, and dynamic virtual complex impedance method for dynamic improvement of response performance of parallel virtual synchronous machine, so as to increase the degree of freedom of dynamic characteristic control and heighten the feedback speed. The parameters of D (damping drop coefficients) and K f (excitation coefficient) to make the inductive component of virtual impedance increase and counteract the resistive component, so as to the oscillation of output power is suppressed; Improving the stability of active power and reactive power and speed up the response speed of the system. The simulation display that parallel VSG in Matlab / Simulink make clear that the proposed control strategy is valid and practicable.