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Structural Design using Cellular Automata
Get PDFTraditional parallel methods for structural design do not scale well. This paper discusses the application of massively scalable cellular automata (CA) techniques to structural design. There are two sets of CA rules, one used to propagate stresses and strains, and one to perform design analysis. These rules can be applied serially,periodically,or concurrently, and Jacobi or Gauss-
Seidel style updating can be done. These options are compared with respect to convergence,speed, and stability
NetEdit: A Collaborative Editor
No full textWe present a collaborative text editor named NetEdit. NetEdit uses a replicated architecture with processing and data distributed across all clients. Due to replication, the response time for local edits is quite close to that of a single-user editor. Clients do not need explicit awareness of other clients since all communication is coordinated by a central server. As a result, NetEdit is quite scalable (linear growth relative to purely distributed systems (quadratic growth) in terms of number of communication paths required as the number of clients grow. NetEdit uses an n-way synchronization algorithm derived from the synchronization protocol of the Jupiter collaboration system. Along with describing the editor, its architecture and its synchronization algorithm, we present the results of a usability study that evaluated the collaboration awareness tools included in NetEdit
Personalization by Partial Evaluation.
Get PDFThe central contribution of this paper is to model personalization by the programmatic notion of partial evaluation.Partial evaluation is a technique used to automatically specialize programs, given incomplete information about their input.The methodology presented here models a collection of information resources as a program (which abstracts the underlying schema of organization and flow of information),partially evaluates the program with respect to user input,and recreates a personalized site from the specialized program.This enables a customizable methodology called PIPE that supports the automatic specialization of resources,without enumerating the interaction sequences beforehand .Issues relating to the scalability of PIPE,information integration,sessioniz-ling scenarios,and case studies are presented
Scalability Analysis of Parallel GMRES Implementations
Get PDFApplications involving large sparse nonsymmetric linear systems encourage parallel implementations of robust iterative solution methods, such as GMRES(k). Two parallel versions of GMRES(k) based on different data distributions and using Householder reflections in the orthogonalization phase, and variations of these which adapt the restart value k, are analyzed with respect to scalability (their ability to maintain fixed efficiency with an increase in problem size and number of processors).A theoretical algorithm-machine model for scalability is derived and validated by experiments on three parallel computers, each with different machine characteristics
A Classification of Interactive Map Software
Get PDFMap software programs can be different in a number of ways. This paper reports on the classification of interactivity produced as a result of surveying forty map applications. Specific examples from the survey are referenced as we describe different navigation styles, different levels of collaboration support, and various data options. Unique combinations within the classification are also discussed as we explore ideas for new interaction technqiues
Polynomial Response Surface Approximations for the Multidisciplinary Design Optimization of a High Speed Civil Transport
Get PDFSurrogate functions have become an important tool in multidisciplinary design optimization to deal with noisy functions, high computational cost, and the practical difficulty of integrating legacy disciplinary computer codes. A combination of mathematical, statistical, and engineering techniques, well known in other contexts, have made polynomial surrogate functions viable for MDO. Despite the obvious limitations imposed by sparse high fidelity data in high dimensions and the locality of low order polynomial approximations, the success of the panoply of techniques based on polynomial response surface approximations for MDO shows that the implementation details are more important than the underlying approximation method (polynomial, spline, DACE, kernel regression, etc.). This paper surveys some of the ancillary techniques—statistics, global search, parallel computing, variable complexity modeling—that augment the construction and use of polynomial surrogates
Map-Based Navigation in a Graphical MOO
Get PDFTraditional MUDs and MOOs lack support for global wareness and simple navigation. These problems can be addressed by the introduction of a map-based navigation tool. In this paper we report on the design and evaluation of such a tool for MOOsburg, a graphical 2D MOO based on the town of Blacksburg, Virginia. The tool supports exploration and place-based tasks in the MOO. It also allows navigation of a large-scale map and encourages users to develop survey knowledge of the town. An evaluation revealed some initial usability problems with our prototype and suggested new design ideas that may better support users. Using these results, the lessons learned about map-based navigation are presented
Programming Environments for Multidisciplinary Grid Communities
No full textRapid advances in technological infrastructure as well as the emphasis on application support systems have signaled the maturity of grid computing. Today’s grid computing environments (GCEs) extend the notion of a programming environment beyond the compile-schedule-execute paradigm to include functionality such as networked access, information services, data management, and collaborative application composition. In this article, we present GCEs in the context of supporting multidisciplinary communities of scientists and engineers. We present a high-level design framework for building GCEs and a space of characteristics that help identify requirements for GCEs for multidisciplinary communities. By describing integrated systems for five different multidisciplinary communities, we outline the unique responsibility (and opportunity) for GCEs to exploit the larger context of the scientific or engineering application, defined by the ongoing activities of the pertinent community. Finally, we describe several core systems support technologies that we have developed to support multidisciplinary GCE applications
Personalized Nuance-Oriented Interaction in Virtual Environments
No full textPersonalized Nuance-Oriented Interaction in Virtual Environment
Dynamic Data Structures for a Direct Search Algorithm
No full textThe DIRECT (DIviding RECTangles) algorithm of Jones, Perttunen, and Stuckman (1993), a variant of Lipschitzian methods for bound constrained global optimization, has proved effective even in higher dimensions. However, the performance of a DIRECT implementation in real applications depends on the characteristics of the objective function, the problem dimension, and the desired solution accuracy. Implementations with static data structures often fail in practice, since it is difficult to predict memory resource requirements in advance. This is especially critical in multidisciplinary engineering design applications, where the DIRECT optimization is just one small component of a much larger computation, and any component failure aborts the entire design process. To make the DIRECT global optimization algorithm efficient and robust on large-scale, multidisciplinary engineering problems, a set of dynamic data structures is proposed here to balance the memory requirements with execution time, while simultaneously adapting to arbitrary problem size. The focus of this paper is on design issues of the dynamic data structures, and related memory management strategies. Numerical computing techniques and modiï¬cations of Jones’ original DIRECT algorithm in terms of stopping rules and box selection rules are also explored. Performance studies are done for synthetic test problems with multiple local optima. Results for application to a site-specific system simulator for wireless communications systems (S4W) are also presented to demonstrate the effectiveness of the proposed dynamic data structures for an implementation of DIRECT