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Cascading Of Ever Adaptive Variation Of Lzw Algorithm With Arithmetic Coding Method, Ramesh Vishwanatham, Ketan Tejani

Theses

Two known compression algorithms appropriate for communication are LZW and the Arithmetic Coding method. Both algorithms are adaptive and require no extra communication from the encoder to the decoder. We have considered a variation of LZW algorithm known as Online version which result in better compression. Here we present a scheme to cascade Online LZW with Arithmetic algorithms into an Ever Adaptive data compression algorithm which achieves higher compression ratio and is appropriate for communication.

Projectile- And Target-Charge Dependent Effects In Ionizing Collisions Of H ⁺ And He 2+ With He, Ne And Ar Atoms, Timothy James Gay, M. W. Gealy, M. E. Rudd

Physics Faculty Research & Creative Works

The spectra of electrons emitted in collisions between H + and He 2+ projectiles and He, Ne and Ar targets at energies of 50 and 100 keV amu -1 have been studied. The data are in qualitative agreement with results of Irby el al., but are in disagreement with measurements of Bernardi et al. It is shown that the observed electron spectra have a dependence on both target-ion and projectile effective charge that can be understood qualitatively in terms of 'saddle-point' ionization. Several issues relevant to saddle-point ionization are discussed. © 1990 IOP Publishing Ltd.

Beryllium-7 And Lead-210 In The Atmosphere And Surface Snow Over The Greenland Ice Sheet In The Summer Of 1989, Jack E. Dibb

Earth Sciences

The concentrations of ⁷Be and ²¹⁰Pb were measured in surface air and fresh and aging snow samples from Summit (72°20′N, 38°45′W) and Dye 3 (65°10′N, 44°45′W) Greenland, during June and July 1989. The aerosol concentrations of these radionuclides showed rapid variations at both sites, but were nearly twice as high, on average, at Summit. Concentrations in the 16 fresh snowfall events that were sampled also showed wide variability, but the averages were the same at the two sites. The apparent difference in air-snow fractionation and the lack of coherence in the concentration in air time series between the …

Three Degrees Of Freedom Compliant Motion Control For Robotic Aircraft Refueling, Clayton M. Andersen

Theses and Dissertations

The Air Force Institute of Technology (AFIT) supports on-going research in application of robotic technology to enhance assembly tasks. As a testbed, AFIT supports the ground-based aerial refueling project, with an emphasis on visual servoing techniques and compliant motion control. This thesis focuses on compliant motion control. Previous research developed the testing environment, which includes a PUMA-560 industrial manipulator, and a half scale mock-up of an aerial refueling system. This effort corrected and expanded the existing two degree of freedom (DOF) compliant controller to three DOF. Three DOF compliance was demonstrated by inserting the refueling nozzle into the receiver port. …

Array Reshaping -- A Mechanism For Optimizing Array Storage On Parallel Architecture, Ko-Yang Wang

Department of Computer Science Technical Reports

No abstract provided.

Heuristic Guided Pre-Optimized Algorithm Substitution For Parallel Computers, Ko-Yang Wang

Department of Computer Science Technical Reports

No abstract provided.

Datascan - December 9, 1990, Nova University

DataScan

No abstract provided.

Models And Algorithms For Co-Scheduling Compute-Intensive Tasks On A Network Of Workstations, Mikhail J. Atallah, Christina Lock, Dan C. Marinescu, Howard J. Seigel, Thomas L. Casavant

Department of Computer Science Technical Reports

No abstract provided.

Brep-Index: A Multi-Dimensional Space Partitioning Tree, George Vanĕček

Department of Computer Science Technical Reports

No abstract provided.

Balancing A Pipeline By Folding, Per Brinch Hansen

Electrical Engineering and Computer Science - Technical Reports

A pipeline for Householder reduction is folded several times across an array of processors to achieve approximate load balancing. The performance of the folded pipeline is analyzed and measured on a Computing Surface.

The All-Pairs Pipeline, Per Brinch Hansen

Electrical Engineering and Computer Science - Technical Reports

An all-pairs problem is a computation on every possible subset consisting of two elements chosen from a set of n elements. N-body simulation and Householder reduction are all-pairs problems. The paper defines the all-pairs problem concisely by means of precedence matrices and derives a parallel algorithm. The algorithm is presented in both coarse-grain and medium-grain form. The all-pairs paradigm is illustrated by a pipeline for Householder reduction of a matrix to triangular form.

A Nonstandard Delta Function, Todor D. Todorov

Mathematics

We prove that the Dirac delta distribution has a kernel in the class of the pointwise nonstandard functions.

The Probe, Issue 106 - December 1990

The Probe: Newsletter of the National Animal Damage Control Association

THE PROBE
National Animal Damage Control Association
DECEMBER 1990
Message from the President
NADCA Membership Meeting in Lincoln
1990 NADCA Membership Directory

Device For Dispersal Of Micrometer- And Submicrometer-Sized Particles In Vaccum, D. P. Sheehan, M. Carillo, W. Heidbrink

Physics and Biophysics: Faculty Scholarship

A simple, versatile device for dispersing micrometer‐ and submicrometer-sized particles in vacuum is described. The source allows control of particle size (0.5 μm≤l≤200 μm) and particle flux density up to roughly 107 cm−2 s−1. Several types of microparticles were successfully dispersed.

Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration

Publications (WR)

The Lake Mead Fertilization Project is a research program designed to investigate the potential for using large-scale artificial fertilization to enhance the game fisheries of this reservoir through an increase in the population of threadfin shad, the system's primary forage species. A substantial decline in the population of largemouth bass, together with poor condition of adult striped bass, are the two major issues affecting the Lake Mead game fisheries. Both issues have been hypothesized to be a result of an inadequate amount of forage in the reservoir. Previous studies have in turn suggested that a major factor limiting the shad …

Cambrian-Early Ordovician Sequence Stratigraphy And Mount Simon Sandstone Petrology-Michigan Basin, Jeffrey T. Cottingham

Masters Theses

Michigan subsurface correlation is complicated in the Cambrian-Early Ordovician section due to limited availability of rock data. Core and cuttings examination demonstrate that similar stratigraphic sequences exist between the Michigan Basin and surrounding regions. Lithofacies in Wisconsin outcrop are similar to their basinal counterparts, and are correlated on the basis of sediment types, sedimentary structures, and the sequence stratigraphic concept.

The Mount Simon Sandstone in Michigan correlates with that observed in Illinois, Wisconsin, and Iowa. Isopach data throughout the Midwest indicate a single depocenter in Northeastern Illinois. Sedimentary structures and lithology indicate a subtidal environment that may be a progradational …

A Report On Black-Tailed Prairie Dogs In Nebraska, Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster

School of Natural Resources: Dissertations, Theses, and Student Research

I examined the effects of a visual barrier fence, which had a see-through visibility of 600/0, on the foraging, vigilance, and aggressive behaviors of adult female black-tailed prairie dogs from June through August 1990 in central Nebraska. I also examined changes in their home ranges and use of an area in response to this fence. Prairie dogs prefer an open view of their surroundings. Therefore, I expected animals near a visual barrier to spend more time in vigilance and aggression, and less time foraging. Adult female prairie dogs exposed to the visual barrier devoted more time to foraging and less …

Graph Products And Covering Graph Imbeddings, Ghidewon Abay Asmerom

Dissertations

No abstract provided.

Improving Networks Reliability, Jamal H. Nouh

Dissertations

No abstract provided.

Horticultural Capability Study Of Soils Adjacent To Plantations At Carnarvon, Western Australia, M R. Wells, J A. Bessell-Browne

Resource management technical reports

A detailed soil survey and horticultural capability assessment was undertaken over 1,804 ha of land adjacent to existing plantations on levees of the Gascoyne River near Carnarvon. The study provides mapped land resource data and advice in relation to land management and the possibility of further land release for horticulture. In the assessment of horticultural capability primary consideration has been given to the risk of erosion during flood events, to salinity, and to soil drainage conditions.

Problems To Test Parallel And Vector Languages -- Ii, John R. Rice, Jin Jing

Department of Computer Science Technical Reports

No abstract provided.

A Low-Cost Part-Task Flight Training System: An Application Of A Head Mounted Display, David A. Dahn

Theses and Dissertations

To investigate the feasibility of using head-mounted display(HMD) and Computer Image Generators(CIG) in a low cost part-task trainer, we created a prototype system. Our approach was to build a virtual world interface using a HMD to an existing flight simulator application. This allowed a CIG with only one graphics channel to drive the display. To investigate which class of computing platform was suitable for use as the CIG, a cooperative thesis effort was launched to host the simulator on a mini-computer and micro-computer platform. The appropriate CIG could then be determined through demonstration and comparison between the systems. A software …

An Empirical Evaluation Of Analytical Models For Parallel Relational Database Queries, Mark C. Denham

Theses and Dissertations

This thesis documents the design and implementation of three parallel join algorithms to be used in the verification of analytical models developed by Kearns. Kearns developed a set of analytical models for a variety of relational database queries. These models serve as tools for the design of parallel relational database system. Each of Kearns' models is classified as either single step or multiple step. The single step models reflect queries that require only one operation while the multiple step models reflect queries that require multiple operations. Three parallel join algorithms were implemented based upon Kearns' models. Two are based upon …

An Empirical Study Of Combining Communicating Processes In A Parallel Discrete Event Simulation, Ann K. Lee

Theses and Dissertations

The primary goal of distributed discrete event simulations is to achieve speedup in simulation execution time by distributing the processing of the simulation over multiple processors. When partitioned for distribution in this fashion, simulations are typically partitioned such that there are more processes than processors. This thesis reviews existing methods for distributed discrete event simulations, and proposes general guidelines for efficient partitioning for a given communications topology based on empirical evidence. A performance analysis is conducted for two approaches to partitioning the system. The first method chosen is a mapping of multiple processes to a processor and the second approach …

Determining Concurrency In Object-Oriented Design Of Real-Time Embedded Systems Using Ada, Kenneth D. Baum

Theses and Dissertations

One of the characteristics of real-time systems is concurrency. Designers of real-time systems have traditionally determined system concurrency at implementation time using the facilities of a cyclic executive. With the advent of programming language constructs for specifying concurrency, determining concurrency at design time has become a possibility. Several design methods, all of which are extensions of either Structured Design or Jackson System Development, provide heuristics to help the designer make concurrency decisions. The object-oriented approach, however, has no corresponding heuristics to aid designers of real-time systems. The purpose of this thesis was to develop heuristics to help designers make concurrency …

Automatic Determination Of Recommended Test Combinations For Ada Compilers, James S. Marr

Theses and Dissertations

Ada compilers are validated using the Ada Compiler Validation Capability (ACVC) test suit, containing over 4000 individual test programs. Each test program focuses, to the extent possible, on a single language feature. Despite the advantages of this atomic testing methodology, it is often the unexpected interactions between language features that result in compilation problems. This research investigated techniques to automatically identify recommended combinations of Ada language features for compiler testing. A prototype program was developed to analyze the Ada language grammar specification and generate a list of recommended of features to be tested. The output from this program will be …

The Development Of A Graphical Notation For The Formal Specification Of Software, Gene A. Place

Theses and Dissertations

The program tranformations lifecycle model, proposed by Balzer in 1984, may hold the key to dramatic leap in software engineer productivity necessitated by the tremendous growth in the world's demand for software. This leap in productivity is made possible by the program transformation lifecycle's reliance on formal specifications rather than programs as the primary vehicle for the creation and maintenance of software systems. Because formal specifications are concerned only with system behaviors and not implementation details, formal specifications tend to present critical system characteristics much more concisely than programs. The major disadvantage of using formal specifications in a software development …

Real-Time Flight Simulation And The Head-Mounted Display - An Inexpensive Approach To Military Pilot Training, Philip A. Platt

Theses and Dissertations

The integration of the low-cost head-mounted display (HMD), an inexpensive graphics workstation-based flight simulator, and a communications network was investigated to determine if the prototype of an inexpensive multi- aircraft Virtual Flight Simulator could be built. Previous research efforts have coupled HMD technology and flight simulation; however, the cost of these systems has been high. This thesis effort emphasized the use of joystick devices to emulate pilot control, the implementation of a fully enclosed virtual flight simulator, and the utilization of low-cost NTSC-based television technology to produce a prototype. The virtual flight simulator also contained a basic set of instruments …

An Ada-Based Framework For An Idef0 Case Tool Using The X Window System, Jay-Evan J. Tevis Ii

Theses and Dissertations

This thesis documents the design strategy, implementation methodology, testing, and evaluation used in developing an Ada-based framework for SAtool II using the X Window System. SAtool II is an IDEF₀ graphical project editor and data dictionary editor. An Ada-Based Framework for an IDEF₀ Case Tool Using the X Window System is the ICAM Definition Method Zero graphical notation language adopted by the U.S. Air Force to produce a function model of a manufacturing system or environment (23:1-1). The Air Force Institute of Technology is conducting on-going research in the use of IDEF₀ in the requirements analysis phase …

A Remote Visual Interface Tool For Simulation Control And Display, William J. Derouchey

Theses and Dissertations

This thesis discusses the design and development of the Visual Interactive Simulation Interface Tool (VISIT). VISIT was designed to provide the graphical representation and user interface for a simulation that is running on another processor utilizing internet communications. The system provides support for various input devices to control the simulation display and environment. Simulation objects are displayed using either a three-dimensional wireframe representation or a Gouraud shaded representation. Viewer interaction to the simulation is provided by a collection of commands that allow the viewer to initialize, start, stop, abort, and restart the simulations. The viewer also has the ability to …