Katarzyna Zajac

Towards a grid management system for HLA-based interactive simulations

This paper presents the design of a system that supports execution of HLA (high level architecture) distributed interactive simulations in an unreliable grid environment. The design of the architecture is based on the OGSA (Open Grid Services Architecture) concept that allows for modularity and compatibility with grid services already being developed. First of all, we focus on the part of the system which is responsible for migration of a HLA-connected component or components of the distributed application in the grid environment. We present a runtime support library for easily plugging HLA simulations into the grid services framework. We also present the impact of execution management (namely migration) on overall system performance.

Grid Services for HLA-Based Distributed Simulation Frameworks

Problem Solving Environments offer an integrating approach for constructing and running complex systems and components, such as distributed simulation and decision support systems. New distributed infrastructures like the Grid support the access to a large variety of core services and resources in a secure environment. In this paper we propose an approach to Grid access for interactive Problem Solving Environments built on top of the High Level Architecture (HLA), a mature distributed simulation framework. This approach is based on a set of Grid Services which allow the setup and interactive steering of complex Grid applications consisting of modules for simulation and visualization. We discuss a three-level approach to the problem. In the first step we focus on discovery of HLA Runtime Infrastructure (RTI) processes that coordinate distributed components of an interactive application. Next we investigate efficient Grid-based data transfer protocols as a promising alternative for current RTI communication. Finally, we will completely replace RTI by Grid technology mechanisms. As a proof-of-concept example, we use the CrossGrid biomedical simulation application, which requires near real time steering of simulation parameters during runtime of the simulation running on the Grid.

Architecture of the grid for interactive applications

In this paper we present the current status of the CrossGrid architecture. The architecture definition follows from the specification of requirements and design documents. It consists of descriptions of functionality of new tools and Grid services and indicates where interfaces should be defined. The components of the CrossGrid architecture are modular and they are organized in the following layers: applications, supporting tools, application development support, application-specific Grid services, generic Grid services, and fabric. We also present an analysis of the possible evolution of the CrossGrid services towards the OGSA service model.

Towards the CrossGrid Architecture

In this paper, basing on the software requirements specifications, we present the CrossGrid architecture. The architecture definition consists of descriptions of functionality of new tools and grid services and indicates where interfaces should be defined. It ought to be perceived as a starting point for a more detailed description of interfaces and technology used for their implementation. The components of the CrossGrid architecture are modular and they are organized in the following layers: applications, supporting tools, application development support, specific grid services, generic grid services, and a fabric layer.

The CrossGrid Architecture: Applications, Tools, and Grid Services

This paper describes the current status of the CrossGrid Project architecture. The architecture is divided into six layers. The relations between main components are presented in UML notation. A flexible concept of plugins that enable creation of uniform user-friendly interface is shown. A brief discussion of OGSA technology and its possible application to CrossGrid services is given as an interesting area of future work.

Component-Based System for Grid Application Workflow Composition

An application working within a Grid environment can be very complex, with distributed modules and decentralized computation. It is not a simple task to dispatch that kind of application, especially when the environment is changing. This paper presents the design and the implementation of the Application Flow Composer system which supports building the description of the Grid application flow by combining its elements from a loose set of components distributed in the Grid. The system is based on the Common Component Architecture (CCA) and uses the CCA distributed component description model. OGSA Registry Grid Service is applied for storing component description documents. The performance tests confirm the feasibility of this approach.

Execution and Migration Management of HLA-Based Interactive Simulations on the Grid

This paper presents the design of a system that supports execution of a HLA distributed interactive simulations in an unreliable Grid environment. The design of the architecture is based on the OGSA concept that allows for modularity and compatibility with Grid Services already being developed. First of all, we focus on the part of the system that is responsible for migration of a HLA-connected component or components of the distributed application in the Grid environment. We present a runtime support library for easily plugging HLA simulations into the Grid Services Framework. We also present the impact of execution management (namely migration) on overall system performance.

Large-Scale Scientific Irregular Computing on Clusters and Grids

Data sets involved in many scientific applications are often too massive to fit into main memory of even the most powerful computers and therefore they must reside on disk, and thus communication between internal and external memory, and not actual computation time, becomes the bottleneck in the computation. The most challenging are scientific and engineering applications that involve irregular (unstructured) computing phases. This paper discusses an integrated approach, namely ideas, techniques, concepts and software architecture for implementing such data intensive applications on computational clusters and the computational Grid, an emerging computing infrastructure. The experimental performance results achieved on a cluster of PCs are included.

Computer Simulation of Ageing with an Extended Penna Model

This paper presents the results of computer simulation obtained with two modifications of the Penna bit-string model of biological ageing. Extinction of population may be caused by number of reasons, overhunting or too many harmful mutations inherited by offsprings among them. In this work we concentrate on population growth dynamics and their age distribution characteristics, such as number of mutations or survival rate, for different hunting and/or inherited harmful mutations rates, and discuss the role of bad mutations threshold fluctuations for possible improvement in health of the final population.

Irregular and Out-of-Core Parallel Computing on Clusters

Clusters of workstations and PC are a popular alternative to integrated parallel systems. Important research topic is development of new methods and software tools for I/O intensive cluster applications. In this paper we propose a parallelization strategy and runtime library solution of the irregular and out-of-core computing.W e also present and discuss experimental performance results using the implementation of the developed software on PC clusters.