Physical Sciences and Mathematics Commons^™

Representing Nodes And Arcs In 3d Networks, Glenn Franck, Colin Ware

Center for Coastal and Ocean Mapping

This paper introduces six graphical principles for 30 network displays. These are justified with examples from GraphVisualizer3D, a system developed by the authors to investigate the problems of 30 visualization of information networks. GraphVisualizer3D enables the exploration of sulface color, surface texture, object shape, arc shape and labeling conventions.

Viewing A Graph In A Virtual Reality Display Is Three Times As Good As A 2d Diagram, Colin Ware, Glenn Franck

Center for Coastal and Ocean Mapping

An experiment is reported which tests whether network information is more effectively displayed in a three dimensional space than in a two dimensional space. The experimental task is to trace a path in a network and the experiment is carried out in 2D, in a 3D stereo view, in a 2D view with head coupled perspective, and in a 3D stereo view with head coupled perspective; this last condition creates a localized virtual reality display. The results show that the motion parallax obtained from the head coupling of perspective is more important than stereopsis in revealing structural information. Overall the …

Improved Algorithms For Bipartite Network Flow, Ravindra K. Ahuja, James B. B. Orlin, Clifford Stein, Robert E. Tarjan

Dartmouth Scholarship

In this paper, network flow algorithms for bipartite networks are studied. A network G = (V,E) is called bipartite if its vertex set V can be partitioned into two subsets V_1 and V_2 such that all edges have one endpoint in V_1 and the other in $V_2 $. Let $n = |V|, n_1 = |V_1 | , n_2 = |V_2 |, m = |E| and assume without loss of generality that n_1 \leqslant n_2. A bipartite network is called unbalanced if n_1 \ll n_2 $ and balanced otherwise. (This notion is necessarily imprecise.) It is shown that several maximum flow …

Hypergraph Partitioning Algorithms, Tom Leighton, Fillia Makedon, Spyros Tragoudas

Computer Science Technical Reports

We present the first polynomial time approximation algorithms for the balanced hypergraph partitioning problem. The approximations are within polylogarithmic factors of the optimal solutions. The choice of algorithm involves a time complexity/approximation bound tradeoff. We employ a two step methodology. First we approximate the flux of the input hypergraph. This involves an approximate solution to a concurrent flow problem on the hypergraph. In the second step we use the approximate flux to obtain approximations for the balanced bipartitioning problem. Our results extend the approximation algorithms by Leighton-Rao on graphs to hypergraphs. We also give the first polylogarithmic times optimal approximation …

Spiders: A New User Interface For Rotation And Visualization Of N-Dimensional Point Sets, William A. Barrett, Kirk L. Duffin

Faculty Publications

We present a new method for creating n-dimensional rotation matrices from manipulating the projections of n-dimensional data coordinate axes onto a viewing plane. A user interface for n-dimensional rotation is implemented. The interface is shown to have no rotational hysteresis.

Defining Locally Shared Memory Constructs For Special Purpose Parallel Architectures, David J. Nielsen

Electrical & Computer Engineering Theses & Dissertations

Locally shared memory systems offer significant advantages over other parallel processing systems for specific classes of problems. Locally shared memory systems tend to be easier to program because explicit passing of messages is not necessary. The goal in defining a locally shared memory system is to allow only a small number of processors access to any single memory. If this goal is met, locally shared memory systems provide an architecture which is relatively simple to implement.

To make shared memory architectures attractive to designers of special purpose parallel architectures, the architectures must be scalable. To be scalable, the number of …

Biofeedback Gait Training Auditory Vs. Visual Techniques, Timothy D. Hiemenz

Electrical & Computer Engineering Theses & Dissertations

Training lower extremity amputees to walk normally is quite a difficult task. Amputees must wear a prosthesis so they can walk at all. This allows them some mobility, but their walking pattern may be unnatural. If their gait is temporally asymmetric, they need to exert more energy to move about. This research was initiated to help lower extremity amputees to walk more efficiently using biofeedback gait training. Two types of feedback were developed and tested to determine which method gave the most understandable feedback, validating its use in a clinical setting.

A normal gait cycle uses the lower limbs to …

A Multiprocessor Extension To The Conventional File System Interface, Nils Nieuwejaar, David Kotz

Computer Science Technical Reports

As the I/O needs of parallel scientific applications increase, file systems for multiprocessors are being designed to provide applications with parallel access to multiple disks. Many parallel file systems present applications with a conventional Unix-like interface that allows the application to access multiple disks transparently. By tracing all the activity of a parallel file system in a production, scientific computing environment, we show that many applications exhibit highly regular, but non-consecutive I/O access patterns. Since the conventional interface does not provide an efficient method of describing these patterns, we present an extension which supports strided and nested-strided I/O requests.

Fluted Formulas And The Limits Of Decidability, William C. Purdy

Electrical Engineering and Computer Science - Technical Reports

In the predicate calculus, variables provide a flexible indexing service that selects the actual arguments to a predicate letter from among possible arguments that precede the predicate letter (in the parse of the formula). In the process of selection, the possible arguments can be permuted, repeated (used more than once), and skipped. If this service is withheld, so that arguments must be the immediately preceding ones, taken in the order in which they occur, the formula is said to be fluted. Quine showed that if a fluted formula contains only homogeneous conjunction (conjoins only subformulas of equal arity), then the …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 7, September 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

A Domain-Specific Parallel Programming System I: Design And Application To Ecological Modelling, Elaine Wenderholm, Micah Beck

Electrical Engineering and Computer Science - Technical Reports

The goal of the εm project is to make parallel programming easily accessible to a broad community of scientists. Previous approaches such as the use of general parallel programming languages and parallelizing compilers for sequential languages have fallen short in this respect. The approach is to design a special purpose programming language which is oriented towards a specific area of application. The result is a specialized and effective scientific tool. εm is a high-level programming system which puts parallelism into the hands of scientists who are not sophisticated programmers. By restricting and simplifying the programming interface, εm eases both the …

Path-Planning For A Mobile Robot Sweeper, Chandrajit Bajaj, Fausto Bernardini, Steve Cutchin, Kokichi Sugihara

Department of Computer Science Technical Reports

No abstract provided.

Science Pad: An Intelligent Electronic Notepad For Ubiquitous Scientific Computing, Anupam Joshi, Sanjiva Weerawarana, Tzvetan T. Drashansky, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

Interpolation Regions For Convex Low Degree Polynomial Curve Segments, Jörg Peters

Department of Computer Science Technical Reports

No abstract provided.

An Analytic Approach For The Asymptotic Distribution Of The Height Of An Incomplete Digital Tree, Hosam Mahmoud, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Constraint-Based Parametric Conics For Cad, Ioannis Fudos, Christoph M. Hoffmann

Department of Computer Science Technical Reports

No abstract provided.

Processing Pde Interface Conditions Ii, Tzvetan Drashansky, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

Objects To The Rescue! Or Httpd: The Next Generation Operating System, Andrew P. Black, Jonathan Walpole

Computer Science Faculty Publications and Presentations

This position paper suggests that object-oriented operating systems may provide the means to meet the ever-growing demands of applications. As an example of a successful OOOS, we cite the http daemon. To support the contention that httpd is in fact an operating system, we observe that it implements uniform naming, persistent objects and an invocation meta-protocol, specifies and implements some useful objects, and provides a framework for extensibility.We also believe that the modularity that is characteristic of OO systems should provide a performance benefit rather than a penalty. Our ongoing work in the Synthetix project at OGI is exploring the …

A New Approach To The Minumum Cut Problem, David R. Karger, Clifford Stein

Computer Science Technical Reports

No abstract provided.

A Macro Extension For The Woody Assembly Language, Lewis Barnett Iii

Department of Math & Statistics Technical Report Series

We discuss an extension to the Woody Assembly Language [Cha94] which allows new instructions to be defined. The mechanism is similar to the C language's #define macros, allowing a name to be supplied for a piece of code which will be expanded in line. Provisions are made for writing new non-destructive branching instructions as well as instructions which are simply new names for commonly used bits of code.

Dynamic File-Access Characteristics Of A Production Parallel Scientific Workload, David Kotz, Nils Nieuwejaar

Computer Science Technical Reports

Multiprocessors have permitted astounding increases in computational performance, but many cannot meet the intense I/O requirements of some scientific applications. An important component of any solution to this I/O bottleneck is a parallel file system that can provide high-bandwidth access to tremendous amounts of data in parallel to hundreds or thousands of processors. Most successful systems are based on a solid understanding of the characteristics of the expected workload, but until now there have been no comprehensive workload characterizations of multiprocessor file systems. We began the CHARISMA project in an attempt to fill that gap. We instrumented the common node …

Stability Criteria For Queueing Networks With A Monotonicity Property, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

A Representation Of Approximate Self- Overlapping Word And Its Application, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Reconstruction Of Rectangles From Projections: An Application To Surface- Mounted Device Placement, Concettina Guerra, Elias N. Houstis, Anupam Joshi

Department of Computer Science Technical Reports

No abstract provided.

Timing Results Of A Parallel Fftsynth, Robert E. Lynch, Zhongyun Zhang

Department of Computer Science Technical Reports

No abstract provided.

Modeling With Collaborating Pde Solvers - Theory And Practice, Mo Mu, John R. Rice

Department of Computer Science Technical Reports

No abstract provided.

Biquartic C1 Spline Surfaces Over Irregular Meshes, Jörg Peters

Department of Computer Science Technical Reports

No abstract provided.

Exact Sor Convergence Regions For A General Class Of P-Cyclic Matrices, A. Hadjidimos, D. Noutsos, M. Tzoumas

Department of Computer Science Technical Reports

No abstract provided.

Problem Solving Environments For Partial Differential Equation Based Applications (Ph.D. Thesis), Sanjiva Weerawarana

Department of Computer Science Technical Reports

No abstract provided.

Some Notes On Multisplitting Methods And M-Step Preconditioners For Linear Systems , A. Hadjidimos, A. K. Yeyios

Department of Computer Science Technical Reports

No abstract provided.