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Overview of a Guide for Electronic Theses and Dissertations
Get PDFThis chapter provides an overview of a guide for electronic theses and dissertations that is being prepared as requested by UNESCO to help with the expansion of ETD activities around the world. It roughly follows the outline developed through discussions involving the many partners working on that guide, coordinated by Shalini Urs. It builds upon experiences related to the evolution of the Networked Digital Library of Theses and Dissertations, a federation of groups interested in ETD programs. It introduces key concepts, explains matters according to the interests of students and universities, highlights technical issues, recommends a scheme for expanding training, and suggests likely future activities
From Cluster to Grid: A Case Study in Scaling-Up a Molecular Electronics Simulation Code
Get PDFThis paper describes an ongoing project whose goal is to significantly improve the performance and applicability of a molecular electronics simulation code. The specific goals are to (1) increase computational performance on the simulation problems currently being solved by our physics collaborators; (2) allow much larger problems to be solved in reasonable time; and (3) expand the set of resources available to the code, from a single homogeneous cluster to a campus-wide computational grid, while maintaining acceptable performance across this larger set of resources. We describe the sequential performance of the code, the performance of two parallel versions, and the benefits of problem-specific load balancing strategies. The grid context motivates the need for runtime algorithm selection; we present a component-based software framework that makes this possible
The Virginia Tech Computational Grid: A Research Agenda
Get PDFAn important goal of grid computing is to apply the rapidly expanding power of distributed
computing resources to large-scale multidisciplinary scientic problem solving. Developing a usable computational grid for Virginia Tech is desirable from many perspectives. It leverages distinctive strengths of the university, can help meet the research computing needs of users with the highest demands, and will generate many challenging computer science research questions. By deploying a campus-wide grid and demonstrating its effectiveness for real applications, the Grid Computing Research Group hopes to gain valuable experience and contribute to the grid computing community. This report describes the needs and advantages which characterize the Virginia Tech context with respect to grid computing, and summarizes several current research projects which will meet those needs
Beyond Harvesting: Digital Library Components as OAI Extensions
Get PDFReusability always has been a controversial topic in Digital Library (DL) design. While componentization has gained momentum in software engineering in general, there has not yet been broad DL standardization in component interfaces. Recently, the Open Archives Initiative (OAI) has begun to address this by creating a standard protocol for accessing metadata archives. It is proposed that this protocol be extended to act as the glue that binds together various components of a typical DL. In order to test the feasibility of this approach, a set of protocol extensions was created, implemented, and integrated as components of production and research DLs. The performance of these components was analyzed from the perspective of execution speed, network traffic, and data consistency. On the whole, this work has simultaneously revealed the feasibility of such OAI extensions for component interaction, and has identified aspects of the OAI protocol that constrain such extensions
Genetic Algorithm with Memory for Optimal Design of Laminated Sandwich Composite Site Panels
No full textThis paper is concerned with augmenting genetic algorithms (GAs) to include memory for continuous variables, and applying this to stacking sequence design of laminated sandwich composite panels that involves both discrete variables and a continuous design variable. The term “memory†implies preserving data from previously analyzed designs. A balanced binary tree with nodes corresponding to discrete designs renders efficient access to the memory. For those discrete designs that occur frequently, an evolving database of continuous variable values is used to construct a spline approximation to the fitness as a function of the single continuous variable. The approximation is then used to decide when to retrieve the fitness function value from the spline and when to do an exact analysis to add a new data point for the spline. With the spline approximation in place, it is also possible to use the best solution of the approximation as a local improvement during the optimization process. The demonstration problem chosen is the stacking sequence optimization of a sandwich plate with composite face sheets for weight minimization subject to strength and buckling constraints. Comparisons are made between the cases with and without the binary tree and spline interpolation added to a standard genetic algorithm. Reduced computational cost and increased performance index of a genetic algorithm with these changes are demonstrated
Effects of Active Exploration and Passive Observation on Spatial Learning in a CAVE
Get PDFThis experiment was a modification of Paul N. Wilson's 1999 study entitled "Active
Exploration of a Virtual Environment Does Not Promote Orientation or Memory for Objects." It
was hoped that changing the immersion level from a standard desktop monitor to a more
immersive CAVE environment would change the results of this experiment.
All subjects explored a three-dimensional virtual environment in a CAVE. Active
subjects were given controls to choose their own path and explore the environment. Passive
subjects watched a playback tour through the virtual environment. A unique active subject
determined the tour for each passive subject. Each subject was asked to remember the objects
they saw, their locations, and the floor plan of the environment.
Afterward, subjects were asked to indicate the direction to another location that was not
visible from the current location. Other object memory tests required recalling the location of
each object and indicating it on a plan view of the environment. Similar to Wilson's experiment,
this experiment yielded no significant indication that active exploration or passive observation
changes the level of spatial learning
Problem Identification and Decomposition within the Requirements Generation Process
Get PDFOnly recently has the real importance of the requirements generation process and its requisite activities been recognized. That importance is underscored by the evolving partitions and refinements of the once all-encompassing (and somewhat miss-named) Requirements Analysis phase of the software development lifecycle. Continuing along that evolutionary line, we propose an additional refinement to the requirements generation model that focuses on problem identification and its decomposition into an associated set of user needs that drive the requirements generation process. Problem identification stresses the importance of recognizing and identifying the difference between a perceived state of the system and the desired one. We mention pre- and post-conditions that help identify and bound the problem and then present some methods and techniques that assist in refining that boundary and also in recognizing essential characteristics of the problem. We continue by presenting a process by which the identified problem and its characteristics are decomposed and translated into a set of user needs that provide the basis for the solution description, i.e, the set of requirements. Finally, to place problem identification and decomposition in perspective, we present them within the framework of the Requirements Generation Model
Scalable Storage for Digital Libraries
Get PDFI propose a storage system optimised for digital libraries. Its key features are its heterogeneous scalability; its integration and exploitation of rich semantic metadata associated with digital objects; its use of a name space; and its aggressive performance optimisation in the digital library domain
Data and Activity Representation for Grid Computing
Get PDFComputational grids are becoming increasingly popular as an infrastructure for computa-
tional science research. The demand for high-level tools and problem solving environments has
prompted active research in Grid Computing Environments (GCEs). Many GCEs have been
one-o development eorts. More recently, there have been many eorts to dene component ar-
chitectures for constructing important pieces of a GCE. This paper examines another approach,
based on a `data-centric' framework for building powerful, context-aware GCEs spanning mul-
tiple layers of abstraction. We describe a scheme for representing data and activities in a GCE
and outline various tools under development which use this representation
Parameter Estimation for a Mathematical Model of the Cell Cycle in Frog Eggs
No full textParameter values for a kinetic model of teh nuclear replication-division cycle in frog eggs are estimated by fitting solutions of the kinetic equations (nonlinear ordinary differential equations) to a suite of experimental observations. A set of optimal parameter values is found by minimizing an objective function defined as the orthodonal distance between the data and the model. The differential equations are solved by LSODAR and the objective function is minimized by ODRPACK. The optimal parameter values are close to the "guesstimates" of the modelers who first studied this problem. These tools are sufficiently general to attack more complicated problems, where guesstimation is impractical or unreliable