CSM Testbed Development and Large-Scale Structural Applications

A research activity called Computational Structural Mechanics (CSM) conducted at the NASA Langley Research Center is described. This activity is developing advanced structural analysis and computational methods that exploit high-performance computers. Methods are developed in the framework of the CSM Testbed software system and applied to representative complex structural analysis problems from the aerospace industry. An overview of the CSM Testbed methods development environment is presented and some new numerical methods developed on a CRAY-2 are described. Selected application studies performed on the NAS CRAY-2 are also summarized

FT-PAS-A framework for pattern specific fault-tolerance in parallel programming

Fault-tolerance is an important requirement for long running parallel applications. Many approaches are discussed in various literatures about providing fault-tolerance for parallel systems. Most of them exhibit one or more of these shortcomings in delivering fault-tolerance: non-specific solution (i.e., the fault-tolerance solution is general), no separation-of-concern (i.e., the application developer's involvement in implementing the fault tolerance is significant) and limited to inbuilt fault-tolerance solution. In this thesis, we propose a different approach to deliver fault-tolerance to the parallel programs using a-priori knowledge about their patterns. Our approach is based on the observation that different patterns require different fault-tolerance techniques (specificity). Consequently, we have contributed by classifying patterns into sub-patterns based on fault-tolerance strategies. Moreover, the core functionalities of these fault-tolerance strategies can be abstracted and pre-implemented generically, independent of a specific application. Thus, the pre-packaged solution separates their implementation details from the application developer (separation-of-concern). One such fault-tolerance model is designed and implemented here to demonstrate our idea. The Fault-Tolerant Parallel Architectural Skeleton (FT-PAS) model implements various fault-tolerance protocols targeted for a collection of (frequently used) patterns in parallel-programming. Fault-tolerance protocol extension is another important contribution of this research. The FT-PAS model provides a set of basic building blocks as part of protocol extension in order to build new fault- tolerance protocols as needed for available patterns. Finally, the usages of the model from the perspective of two user categories (i.e., an application developer and a protocol designer) are illustrated through examples

Integrating CLIPS applications into heterogeneous distributed systems

SOCIAL is an advanced, object-oriented development tool for integrating intelligent and conventional applications across heterogeneous hardware and software platforms. SOCIAL defines a family of 'wrapper' objects called agents, which incorporate predefined capabilities for distributed communication and control. Developers embed applications within agents and establish interactions between distributed agents via non-intrusive message-based interfaces. This paper describes a predefined SOCIAL agent that is specialized for integrating C Language Integrated Production System (CLIPS)-based applications. The agent's high-level Application Programming Interface supports bidirectional flow of data, knowledge, and commands to other agents, enabling CLIPS applications to initiate interactions autonomously, and respond to requests and results from heterogeneous remote systems. The design and operation of CLIPS agents are illustrated with two distributed applications that integrate CLIPS-based expert systems with other intelligent systems for isolating and mapping problems in the Space Shuttle Launch Processing System at the NASA Kennedy Space Center

Sixth Annual Users' Conference

Conference papers and presentation outlines which address the use of the Transportable Applications Executive (TAE) and its various applications programs are compiled. Emphasis is given to the design of the user interface and image processing workstation in general. Alternate ports of TAE and TAE subsystems are also covered

An Event Monitor and Response Framework Based on the WSLogA Architecture

Web services provide organizations with a powerful infrastructure by which information and products may be distributed, but the task of supporting Web service systems can be difficult due to the complex nature of environment configuration and operation. Tools are needed to monitor and analyze such Enterprise environments so that appropriate engineering, quality control, or business activities can be pursued. This investigation resulted in the development of a software development kit, the WSLogA Framework, which is inspired by the vision of Cruz et al. (2003, 2004). The WSLogA Framework provides distributed Enterprise systems with a platform for comprehensive information capture and environment management. Five component groups are intended for employment to enable integrated workflows addressing monitoring and response activities, but these components may also be used individually to facilitate the phased integration of the WSLogA Framework into existing environments. The WSLogA Framework\u27s design is portable across technology platforms (e.g., Java and .NET) and a variety of technologies may be substituted for the provided implementations to address unique system architectures. The WSLogA Framework supersedes existing logging and monitoring solutions in terms of both capability and intent. Applications based on the WSLogA Framework have an internal, real-time view of their operation and may adjust their environment based on the information provided by events related to their or system activities. The WSLogA Framework is intended as a software development kit around which system functionality may be organized and implemented, which makes the WSLogA Framework an architectural peer or complement to traditional application frameworks such as Spring\u27s Web module. WSLogA Framework based systems should be envisioned as information appliance elements rather than traditionally scoped applications or services

Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

Monitorable network and CPU load statistics and their application to scheduling

Recent trends in high-speed computing have moved towards the use of networks of workstations as a cost-effective approach to parallel computing. One recently proposed solution involves the use of an existing network of workstation-class computers as a single multiprocessor, and much research is ongoing in this area;This dissertation describes work in the area of process scheduling on networks of workstations, specifically in the area of load analysis. After presenting extensive background in the field, measures of CPU and network load are defined, and a test parallel application program presented, written for a network-multiprocessing software package called PVM. A series of experiments is then detailed, whose goal was to discover the relationship between the run time of the test application and the loads on the participating workstations and networks. The experiments include measurement of CPU loading and network loading, both during test application runs, during artificially elevated loads, and during quiet conditions. Results of the experiments are presented, and the applications of the results to the problem of task scheduling examined. It is then claimed that several easily measured load measures are useful to task scheduling, by allowing run time to be predicted within a margin of error, and allowing limiting network segments to be detected and avoided

A systems approach to the development of large Geographic Information Systems

Includes bibliography.Large computer-based information systems seldom achieve unqualified success. The major problem is organisational rather than technical, hence to achieve greater success in system implementation greater emphasis must be given to organisational issues than to technology. Current practise, however, tends to focus on technical issues. The aim of this research was to investigate whether a systems-based approach would lead to better understanding of the system development process, and hence form the basis of a methodology which would lead to greater success in computer-based information system implementation. The thesis comprises four parts. In the first part (Chapters 1 - 5) the literature on systems theory in sociology with particular reference to business organisations is reviewed. This review focuses on the historical development of systems thinking, particularly in business management. Beer's Viable System Model, Checkland' s Soft Systems Methodology, and Hoebeke' s ideas on the adoption of new technology provided the main ideas for developing a conceptual model for the information system development process. In the second part (Chapters 6-9) this model is applied to the information system development process to identify the strengths and weaknesses of current methods. Each stage of system development from planning to implementation is considered from a systems perspective. This involves identifying the key stakeholders, and understanding their role in the development process. In the next part three case studies are examined in the light of the theoretical material. The impact of inter-cultural communication is highlighted in these studies as the developers and customers were from· several different cultures. The author was personally involved as project manager and chief consultant in the development of two of the systems described. He was also fully aware of the progress of the other case because that development was being undertaken in the same office. Regular exchanges of views on the progress of each project took place. In the final chapter the conclusions are presented. The main conclusion is that information system implementation must be undertaken within the overall context of the organisation, must be closely aligned with the organisational business processes, and must address the conflicting needs of the different stakeholders. Effective Communication between system developers and system users is crucial to success. A focussed effort is required to achieve effective communication in a multi-cultural environment

Engineering Automation for Reliable Software Interim Progress Report (10/01/2000 - 09/30/2001)

Prepared for: U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211The objective of our effort is to develop a scientific basis for producing reliable software that is also flexible and cost effective for the DoD distributed software domain. This objective addresses the long term goals of increasing the quality of service provided by complex systems while reducing development risks, costs, and time. Our work focuses on "wrap and glue" technology based on a domain specific distributed prototype model. The key to making the proposed approach reliable, flexible, and cost-effective is the automatic generation of glue and wrappers based on a designer's specification. The "wrap and glue" approach allows system designers to concentrate on the difficult interoperability problems and defines solutions in terms of deeper and more difficult interoperability issues, while freeing designers from implementation details. Specific research areas for the proposed effort include technology enabling rapid prototyping, inference for design checking, automatic program generation, distributed real-time scheduling, wrapper and glue technology, and reliability assessment and improvement. The proposed technology will be integrated with past research results to enable a quantum leap forward in the state of the art for rapid prototyping.U. S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-22110473-MA-SPApproved for public release; distribution is unlimited

Application of the internet technology and client/server paradigm for the implementation of REPI

There are many problems associated with Requirements Engineering such as defining the system scope, developing understanding among the communities involved in the system to be built, volatility of requirements etc. These problems may lead to poor requirements and therefore cancellation of the system development, or else the development of a system that is unsatisfactory, has high maintenance cost or is unacceptable. By improving Requirements Elicitation, the Requirements Engineering can be improved, leading to a better requirements specification and eventually a better product. Requirements Elicitation requires effective communication among the team members, as communication is the key factor. Easing communications between stakeholders and developers makes the process of Requirements Elicitation easier. REPI guides team members through the elicitation phase using the SEI\u27s framework. REPI forces stakeholders to explicitly describe the requirements resulting in reduced chances of misunderstood requirements, leading to better requirements specification