Physical Sciences and Mathematics Commons^™

A Theoretical Study Concerning The Solar Cycle Dependence Of The Nightside Ionosphere Of Venus, Zoltan Dobe, Andrew F. Nagy, Jane L. Fox

Physics Faculty Publications

We modeled the chemical and physical processes taking place in the nightside ionosphere of Venus by solving the one dimensional coupled continuity and momentum equations for 12 ion species [CO₂⁺, O₂⁺, O⁺, H⁺, NO⁺, CO⁺, N₂⁺, N⁺, He⁺, C⁺, O⁺ (²D) and O⁺ (²P)]. We investigated the relative importance of the two major processes responsible for maintaining the nightside plasma densities: atomic ion transport from the dayside and impact ionization due to energetic electron precipitation. …

Monte-Carlo Simulation Of Bulk Hole Transport In Alxga1-Xas, In1-Xalxas, And Gaasxsb1-X, M. J. Martinez, David C. Look, J. R. Sizelove, F. L. Schuermeyer

Physics Faculty Publications

We report a Monte Carlo study of hole transport in Al_xGa_1−xAs, In_1−xAl_xAs, and GaAs_xSb_1−x. The effects of alloy scattering are significant in all three cases, but mobilities are still high enough to be advantageous in particular device applications. We separately calculate the Hall r factors by a Boltzmann transport method and show that these factors are vitally important when attempting to compare Monte Carlo drift mobilities with experimental Hall data.

Demonstration Of Semiconductor Characterization By Phonon Side-Band In Photoluminescence, D. C. Reynolds, David C. Look, D. N. Talwar, G. L. Mccoy, K. R. Evans

Physics Faculty Publications

In this paper two GaAs samples were investigated; one was a very pure sample grown by chemical-vapor deposition, the other was grown by molecular-beam epitaxy. The dominant optical transition in the high-purity sample was the donor-bound-exciton transition. Phonon sidebands associated with both the free exciton and the donor-bound exciton were observed. The active phonons were the longitudinal-optical (LO) and the transverse-optical (TO) modes associated with both the free exciton and the donor-bound exciton at the Γ point in k space; the TO mode from the donor-bound exciton at the X point, the LO from the free exciton at the L …

A Multithreaded Message Passing Environment For Atm Lan/Wan, Rajesh Yadav, Rajashekar Reddy, Salim Hariri, Geoffrey C. Fox

Northeast Parallel Architecture Center

Large scale High Performance Computing and Communication (HPCC) applications (e.g. Video-on-Demand, and HPDC) would require storage and processing capabilities which are beyond existing single computer systems. The current advances in networking technology (e.g. ATM) have made high performance network computing an attractive computing environment for such applications. However, using only high speed network is not sufficient to achieve high performance distributed computing environment unless some hardware and software problems have been resolved. These problems include the limited communication bandwidth available to the application, high overhead associated with context switching, redundant data copying during protocol processing and lack of support to …

Multiquadric Interpolation: Surface Fitting In Three-Dimensional Space, Michelle Ruse

Presidential Scholars Theses (1990 – 2006)

Using mathematics to solve a problem does not always yield a perfect or absolute answer but may instead yield an approximate solution. We can try to approximate the solution as precisely as possible by using the mathematical tools and skills that are available to us or we could try to discover new methods which would enable us to find good approximations. It is important that we have precise approximating tools to begin with, so that we may preserve as much accuracy as possible.

We can find such problems in the world around us. For instance, if we try to construct …

A Personal Identification Biometric System Based On Back-Of-Hand Vein Patterns, A. J. Mehnert, J. M. Cross, C. L. Smith, K. Y. Chia

Research outputs pre 2011

This report describes research on the use of back-of-hand vein patterns as a means of uniquely identifying people. In particular it describes a prototype biometric system developed by the Australian Institute of Security and Applied Technology (AISAT). This system comprises an infrared cold source, a monochrome CCD camera, a monochrome frame-grabber, a personal computer, and custom image acquisition, processing, registration, and matching software. The image processing algorithms are based on Mathematical Morphology. Registration is performed using rotation and translation with respect to the centroid of the two-dimensional domain of a hand. Vein patterns are stored as medial axis representations. Matching …

Impact Of Artificial Reef Associates On Macrobenthic Community Structure In Florida Bay, Heinz Michael Proft

Dissertations, Theses, and Masters Projects

No abstract provided.

Lead In Kentucky Soils, T. W. Struttmann, Lyle V. A. Sendlein, Dave Fletcher

KWRRI Research Reports

This study reviewed the literature on the occurrence of lead in soils and its relationship to waste oil tank leaks. Many studies have been conducted on the natural occurrence of lead in rocks, soils and water. Very low levels (0.001 mg/l to 0.01 mg/l) are found in surface and groundwater, variable levels are found in soils (from less that 10 ppm to as high as 700 ppm but more normally a high of 70 ppm), and the lead levels found in rocks range from 7 to 80 mg/kg.

Risk assessment calculations have been made by several individuals, also with variable …

Risk Assessment Plan For Petroleum Underground Storage Tanks In Kentucky, Wesley J. Birge, L. C. Taylor, M. D. Kircher, A. J. Grant

KWRRI Research Reports

This study addresses the development of guidelines for corrective actions to be applied to petroleum underground storage tanks (USTs) within the Commonwealth of Kentucky. The report presents findings and recommendations for gasoline, diesel fuel, heating oil, kerosene, jet fuel, and waste oil.

Risk Assessment Plan For Petroleum Underground Storage Tanks In Kentucky, Part 1: Gasoline, Wesley J. Birge, M. D. Kercher, D. P. Keogh, L. C. Taylor

KWRRI Research Reports

This report consists of three appendix:

• I Risk Assessment Procedures and Calculations
• II BTEX Half-life Estimates in Air, Soil, Groundwater, and Surface Water
• III Environmental and Ecological Effects of BTEX

Effect Of Subsoiling On Yield Of Burley Tobacco, Kenneth L. Wells, Kim D. Strohmeier

Soil Science News and Views

Compaction of tobacco fields caused by overworking or working soils when they are too wet has become a topic of concern to burley producers in recent years. Despite the viewpoint of some producers that annual subsoiling of tobacco fields is a profitable practice, particularly on soils which percolate water slowly, the University of Kentucky College of Agriculture recommends subsoiling only for a defined compaction problem. In such cases, some field studies have shown increased yields of burley to tillage practices that penetrate and shatter the compacted layer. Questions persist, however, about the effectiveness of single shank subsoilers used annually by …

Analysis Of Rule Sets Generated By The Cn2, Id3, And Multiple Convergence Symbolic Learning Methods, Elizabeth M. Boll, Daniel C. St. Clair

Mathematics and Statistics Faculty Research & Creative Works

The ability to learn has long been an area of interest to researchers in artificial intelligence. Symbolic inductive learning algorithms have evolved as a class of algorithms that can be used to learn concepts from training examples. The knowledge acquired is represented in the form of rules. Since symbolic learning methods develop distinctive sets of rules when given identical training data, questions arise as to the quality of the different rule sets produced. The results of this research provide techniques for comparing and analyzing rule sets. Numerous rule sets were generated using three well-known symbolic learning methods; Quinlan's ID3, Clark …

The Imprint Of Tsunami In Quaternary Coastal Sediments Of Southeastern Australia, R. W. Young, Edward A. Bryant, David M. Price, E. Spassov

Faculty of Science - Papers (Archive)

TL and 14C dating has revealed anomalous chronostratigraphies at two sites on the coast of southern New South Wales, Australia, where Pleistocene sands have been driven onshore over Holocene estuarine deposits. Lack of solar bleaching of the TL component which occurs in normal swash zones, an identical TL age obtained from pumice incorporated in the Pleistocene deposit, and boulders scattered through the sand are indicative of tsunami impact. These observations prompt reassessment of the strictly uniformitarian models of barrier emplacement during the Holocene transgression both in eastern Australia and elsewhere in the world where tsunami are a possibility.

Structures Of Cryptographic Functions With Strong Avalanche Characteristics, Jennifer Seberry, Xian-Mo Zhang, Yuliang Zheng

Faculty of Informatics - Papers (Archive)

This paper studies the properties and constructions of non linear functions, which are a core component of cryptographic primi- tives including data encryption algorithms and one-way hash function. A main contribution of this paper is to reveal the relationship between nonlinearity and propagation characteristic, two critical indicators of the cryptographic strength of a Boolean function. In particular, (we prove that (i) if f, a Boolean function on V_n, satisfies the propagation criterion with respect to all but a subset R of vectors in V_n, then the nonlinearity of f satisfies N_f ≥ 2 ^n-1 - …

Survey Of Hematozoa And Intestinal Helminths Infecting Green-Winged Teal In Guthrie County, Iowa, Rick Klann, Bryan Hellyer

Journal of the Iowa Academy of Science: JIAS

Five helminths and one sporozoan were recovered from 21 hunter-killed green-winged teal collected from Lakin Slough in Guthrie County, Iowa during October and November of 1991. The sporozoan, Leucocytozoon simondi, was identified in blood smears from all 21 teal. The helminths recovered from the alimentary tract included three trematodes, Cotylurus flabelliformis, Echinostoma trivolvis and Zygocotyle lunata; a hymenolepid tapeworm; and one acanthocephalan, Corynosoma constrictum. The ecological factors associated with infection by these parasites are discussed.

Inheritance And Number Of Genes Affecting Quantitative Traits Within F2 Maize Populations, D. H. Schmidt, A. R. Hallauer

Journal of the Iowa Academy of Science: JIAS

Populations derived from crosses of elite genotypes are commonly used in plant breeding programs. Knowledge of the genetic variation among individuals and their progenies within F2 populations is essential for effective selection of important traits. The genetic variation and number of effective factors affecting the expression of quantitative traits within 30 F2 maize (Zea mays L.) populations were determined by different methods suggested for study of F2 populations. Estimates of heritability and number of effective factors varied among F2 populations for each trait, primarily because of the differences in trait expression between parents of crosses and the environmental effects upon …

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Annual Report Of The Iowa Academy Of Science, 1994-95, Paul E. Rider

Journal of the Iowa Academy of Science: JIAS

Since 1976, annual reports have served as a continuing record of the activities of the Iowa Academy of Science and an archive for its history. These augment the 100 year IAS history written in the centennial year of 1975.

This report covers the period from July 1, 1994 to June 30, 1995. It is based on the official records of the Academy (committee reports, Board minutes, correspondence) as well as the recollections, impressions and thoughts of the author.

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Front Matter

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Front Matter

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Hydrogeology Of The Devonian-Silurian Carbonate Aquifer, Northern Cedar Rapids, Iowa, Keith E. Schilling

Journal of the Iowa Academy of Science: JIAS

The hydrogeology of the Devonian-Silurian carbonate aquifer was investigated at a hazardous waste site in northern Cedar Rapids, Iowa. Data collected at the project site included bedrock cores, specific capacity measurements in discrete packer intervals and monitoring wells, hydraulic-head measurements and groundwater samples collected from select Devonian and Silurian wells.

Nonrecursive Incremental Evaluation Of Datalog Queries, Guozhu Dong, Jianwen Su, Rodney Topor

Kno.e.sis Publications

We consider the problem of repeatedly evaluating the same (computationally expensive) query to a database that is being updated between successive query requests. In this situation, it should be possible to use the difference between successive database states and the answer to the query in one state to reduce the cost of evaluating the query in the next state. We use nonrecursive Datalog (which are unions of conjunctive queries) to compute the differences, and call this process “incremental query evaluation using conjunctive queries”. After formalizing the notion of incremental query evaluation using conjunctive queries, we give an algorithm that constructs, …

Fault Healing Inferred From Time Dependent Variations In Source Properties Of Repeating Earthquakes, Chris Marone, John E. Vidale, William L. Ellsworth

United States Geological Survey: Staff Publications

We analyze two sets of repeating earthquakes on the Calaveras fault to estimate in-situ rates of fault strengthening (healing). Earthquake recurrence intervals t, range from 3 to 803 days. Variations in relative moment and duration are combined to study changes in stress drop, rupture dimension, rupture velocity, and particle velocity as a function of t_r. Healing rates and source variations are compared with predictions of laboratory derived friction laws. Two interpretations of event duration τ are used: one in which τ: is given by the ratio of slip to particle velocity and one in which it scales as …

Foreshock Sequence Of The 1992 Landers, California, Earthquake And Its Implications For Earthquake Nucleation, Douglas A. Dodge, Gregory C. Beroza, W. L. Ellsworth

United States Geological Survey: Staff Publications

The June 28, 1992, Landers, California, earthquake(M_w=7.3) was preceded for about 7 hours by a foreshock sequence consisting of at least 28 events. In this study we examine the geometry and temporal development of the foreshocks using high-precision locations based on cross correlation of waveforms recorded at nearby stations. By aligning waveforms, rather than trying to obtain travel time picks for each event independently, we are able to improve the timing accuracy greatly and to make very accurate travel time picks even for emergent arrivals. We perform a joint relocation using the improved travel times and reduce the …

Bermuda Solution Pipe Soils: A Geochemical Evaluation Of Eolian Parent Materials, Stanley R. Herwitz, Daniel R. Muhs

United States Geological Survey: Staff Publications

Solution pipes found in the Quaternary eolian and marine carbonates of Bermuda are filled with reddish to reddish-brown soil material. The bulk of the soil is composed of clay and silt-sized quartz and aluminosilicate clay minerals. The carbonates are of high purity and, therefore, are not likely to have been the parent material. Previous workers have hypothesized that Saharan dust may have been the soil parent material. The fine-grained component of loess from the Mississippi River Valley of North America also could have contributed. Paleoclimate models indicate that both North Africa and North America could have been important source areas …

Resuspension Behavior In The Lower Chesapeake Bay, J.P. -Y Maa, C. -H. Lee

VIMS Books and Book Chapters

Using the VIMS Sea Carousel to conduct in-situ experiments in lower Chesapeake Bay, we found significant spatial a.nd temporal difference of the critical bed shear stress for sediment resuspension, tcr- At the Wolftrap site, tcr varied from 1.1 Pa in the summer to 1.9 Pa in the winter. At the Burwell Bay site, although the bed was too soft for anchoring our research vessel against the changing tide, we identified that tcr was 0.045 Pa. At the Old Plantation site, there was a small amount of fluffy material on top of the bed. At a winter deployment at the Cherrystone …

Aras: Asynchronous Risc Architecture Simulator, Chia-Hsing Chien, Mark A. Franklin, Tienyo Pan, Prithvi Prabhu

All Computer Science and Engineering Research

In this paper, an asynchronous pipeline instruction simulator, ARAS is presented. With this simulator, one can design selected instruction pipelines and check their performance. Performance measurements of the pipeline configuration are obtained by simulating the execution of benchmark programs on the machine architectures developed. Depending on the simulation results obtained by using ARAS, the pipeline configuration can be altered to improve its performance. Thus, one can explore the design space of aynchronous pipeline architectures.

Pac Learing Of One-Dimensional Patterns, Paul W. Goldberg, Sally A. Goldman, Stephen D. Scott

All Computer Science and Engineering Research

Developing the ability to recognize a landmark from a visual image of a robot's current location is a fundamental problem in robotics. We consider the problem of PAC-learning the concept class of geometric patterns where the target geometric pattern is a configuration of k points on the real line. Each instance is a configuration of n points on the real line, where it is labeled according to whether or not it visually resembles the target pattern. To capture the notion of visual resemblance we use the Hausdorff metric. Informally, two geometric patterns P and Q resemble each othe runder the …