Digital Commons Network^™

Neutral-Plasma Oscillations At Zero Temperature, Scott D. Bergeson, Ross L. Spencer

Faculty Publications

Cold plasma theory is used to calculate the response of an ultracold neutral plasma to an applied rf field. The free oscillation of the system has a continuous spectrum and an associated damped quasimode. This quasimode dominates the driven response and is resonant in the tail of the density distribution. Recent experiments used the plasma response to an applied rf field to determine the plasma density in an expanding ultracold plasma. The comparison between experiment and theory indicates that this method accurately determines the expansion velocity and underestimates the initial plasma density by a factor of 3 in weakly collisional …

Memory-Based Tone Recognition Of Cantonese Syllables, Michael William Emonts

Theses and Dissertations

Speech recognition has only recently been applied to Cantonese. Considerable effort, however, has been spent in recognizing Mandarin, the standard dialect of Chinese. Prior to this thesis, the only published work on monosyllabic Cantonese tone recognition is from Tan Lee et al. (1993,1995). This thesis is the first of its kind in that it explores memory-based learning as a viable approach for Cantonese tone recognition. The memory-based learning algorithm employed in this thesis outperforms the highly respected and widely used neural network approach. Various numbers of tones and features are modeled to find the best method for feature selection and …

Bounding The Number Of Graphs Containing Very Long Induced Paths, Steven Kay Butler

Theses and Dissertations

Induced graphs are used to describe the structure of a graph, one such type of induced graph that has been studied are long paths.

In this thesis we show a way to represent such graphs in terms of an array with two colors and a labeled graph. Using this representation and the techniques of Polya counting we will then be able to get upper and lower bounds for graphs containing a long path as an induced subgraph.

In particular, if we let P(n,k) be the number of graphs on n+k vertices which contains P_n, a path on n vertices, as …

Time Aliasing Methods Of Spectrum Estimation, Jason F. Dahl

Theses and Dissertations

Time aliasing methods of spectrum estimation alter the time representation of a signal for the purpose of improving its frequency domain representation. Time aliasing allows characteristics of longer time window functions to be used with shorter DFT length. Windows designed specifically for use with time aliasing have improved properties compared to conventional windows. Many previous uses of time aliasing, including overlap-and-add methods of digital filtering, have focused on the elimination of time aliasing effects in the frequency domain in order to improve the representation of reconstructed signals in the time domain and have not addressed the issues associated with spectrum …

Chemomechanical Surface Patterning And Functionalization Of Silicon Surfaces Using An Atomic Force Microscope, Brent A. Wascaser, Michael J. Maughan, Travis L. Niederhauser, Matthew R. Linford, Robert C. Davis, Ian A. Mowat

Faculty Publications

Surface modification and patterning at the nanoscale is a frontier in science with significant possible applications in biomedical technology and nanoelectronics. Here we show that an atomic force microscope (AFM) can be employed to simultaneously pattern and functionalize hydrogen-terminated silicon (111) surfaces. The AFM probe was used to break Si-H and Si-Si bonds in the presence of reactive molecules, which covalently bonded to the scribed Si surface. Functionalized patches and patterned lines of molecules were produced. Linewidths down to 30 nm were made by varying the force at the tip

Writing A Web Library User's Guide To The East Asian Languages Collection Of The University Of California-Davis, Mei-Yun (Annie) Lin

Journal of East Asian Libraries

No abstract provided.

Real Time Dynamic Trajectory Smoothing For Uninhabited Aerial Vehicles, Erik Anderson, Randal Beard, Timothy W. Mclain

Faculty Publications

Sponsorship: AFOSR, DARPA. This paper presents a real-time, feasible trajectory generation algorithm for unmanned air vehicles (UAVs) flying through a sequence of waypoints. The algorithm produces extremal trajectories that transition between straight-line path segments in a time-optimal fashion. In addition, the algorithm can be configured so that the dynamically feasible trajectory has the same path length as the straight-line waypoint path. Implementation issues associated with the algorithm are described in detail. Simulation studies show the effectiveness of the proposed method.

Benthic Insect Fauna Of A Clean-Water Stream On Utah's Colorado Plateau, Usa, C. A. Brammer, J. F. Macdonald

Western North American Naturalist

Extensive collecting using a variety of methods was conducted in 1994 and 1995 in association with Pleasant Creek in south central Utah, USA, in an effort to inventory the aquatic insects. Collecting efforts yielded 133 insect taxa from 12 sample sites in 8 study areas from near the headwaters of Pleasant Creek and downstream to where it flows out of Capitol Reef National Park. Applying Protocol III methodology of Plafkin et al. (1989), we determined species assemblages of benthic insects and calculated selected ecological indices based on monthly collections from March through August 1994. Richness, equitability index, and mean diversity …

Every Three-Point Set Is Zero Dimensional, David L. Fearnley, J. W. Lamoreaux, David L. Fearnley

Faculty Publications

This paper answers a question of Jan J. Dijkstra by giving a proof that all three-point sets are zero dimensional. It is known that all two-point sets are zero dimensional, and it is known that for all n > 3, there are n-point sets which are not zero dimensional, so this paper answers the question for the last remaining case.

Odd Perfect Numbers Have A Prime Factor Exceeding 10^7, Paul M. Jenkins

Faculty Publications

It is proved that every odd perfect number is divisible by a prime greater than 10^7.

Muhammad, Judah, And Joseph Smith: A Sharp Stick In The Eye, Brian M. Hauglid

Review of Books on the Book of Mormon 1989–2011

Review of C. Reynolds Mackay. Muhammad, Judah, and Joseph Smith.

How Polemicism Corrupted Latter-Day Saint Apologetics, Benjamin I. Huff

Review of Books on the Book of Mormon 1989–2011

Review of Richard R. Hopkins. How Greek Philosophy Corrupted the Christian Concept of God.

For The Want Of Ten Dollars: The Development Of The Terra Cotta Industry In New Jersey, Thorvald Hansen

The Bridge

When the Mathiasens, Karl and his father, left Thisted, on Denmark's northeast Jutland peninsula, for America in 1872, the intention of the elder Mathiasen was to go to Michigan where he had a sister living. When they arrived in New York the father totaled up the funds he had and discovered that the trip thus far had cost more than he expected. He lacked ten dollars of having enough to travel farther west. On the advice of a kindly Dane they walked the few miles to Perth Amboy, New Jersey where they were told they could probably find work. It …

Comparisons Of Local Infiltration-Excess, Overland Flow And Associated Erosion Behaviour With River Behaviour At The Catchment Scale

Journal of Spatial Hydrology

Modeling overland flow and erosional behaviour is a very important scientific task today to prevent environmental impacts from human activities as well as physical disasters such as floods and desertification. In the particular project the impacts from selective logging that occurred in Malaysia has been attempted to identify and quantify by comparing hydrological parameters both in local and catchment scale. Measurements of rainfall, overland flow and suspended sediment flux have been recorded for a year with a resolution of five minutes. A Databased Mechanistic (DBM) modeling approach has been applied to the data to facilitate physical interpretation of the results, …

Spatially Distributed Watershed Mapping And Modeling: Gis-Based Storm Runoff Response And Hydroraph Analysis: Part 2

Journal of Spatial Hydrology

Advances in scientific knowledge and new techniques of remote sensing permit a better understanding of the physical land features governing hydrologic processes, and make possible efficient, large-scale hydrologic modeling. The need for land-cover and hydrologic response change detection at a larger scale and at times of the year when hydrologic studies are critical makes satellite imagery the most cost effective, efficient and reliable source of data. In this work, remotely-sensed data and geographic information system (GIS) tools were used to estimate the changes in runoff response for three watersheds (Etonia, Econlockhatchee, and S-65A sub- basins) in Florida. Land-use information from …

Determination Of Home Techniques For Storing And Conserving Food In The Homes Of Cuambo And La Rinconada In Imbabura Province, 2001-2002, Marisol Caicedo Barrios

Theses and Dissertations

In Ecuador, there is a grave socioeconomic nutritional problem, and it is seen clearest in Imbabura province in the communities of Cuambo and La Rinconada. One of the biggest problems is inadequate food, due principally to the poor food storage and conservation habits. Considering this problem, it is necessary to deepen the knowledge of improved traditional techniques for storing and conserving food, through which families can store and manage their product better, controlling and avoiding losses due to insects, rodents, and climate, and guaranteeing conservation of the same. The investigation was oriented to implement alternative, improved storage and conservation technologies …

Testing Forward Exchange Rate Unbiasedness Efficiently: A Semiparametric Approach, Douglas J. Hodgson, Oliver Linton, Keith Vorkink

Faculty Publications

We apply semiparametric efficient estimation procedures for a seemingly unrelated regression model where the multivariate error density is elliptically symmetric to study the efficiency of the foreign exchange market. We consider both cointegrating regressions and standard stationary regressions. The elliptical symmetry assumption allows us to avoid the curse of dimensionality problem that typically arises in multivariate semiparametric estimation procedures, because the multivariate elliptically symmetric density function can be written as a function of a scalar transformation of the observed multivariate data. We test the unbiasedness hypothesis on both weekly and daily exchange rate data and strongly reject unbiasedness at the …

A Memory-Based Approach To Cantonese Tone Recognition, Deryle W. Lonsdale, Michael Emonts

Faculty Publications

This paper introduces memory-based learning as a viable approach for Cantonese tone recognition. The memorybased learning algorithm employed here outperforms other documented current approaches for this problem, which is based on neural networks. Various numbers of tones and features are modeled to find the best method for feature selection and extraction. To further optimize this approach, experiments are performed to isolate the best feature weighting method, the best class voting weights method, and the best number of k-values to implement. Results and possible future work are discussed.

A Comparison Of Partially Adaptive And Reweighted Least Squares Estimation, Brian H. Boyer, James B. Mcdonald, Whitney K. Newey

Faculty Publications

The small sample performance of least median of squares, reweighted least squares, least squares, least absolute deviations, and three partially adaptive estimators are compared using Monte Carlo simulations. Two data problems are addressed in the paper: (1) data generated from non-normal error distributions and (2) contaminated data. Breakdown plots are used to investigate the sensitivity of partially adaptive estimators to data contamination relative to RLS. One partially adaptive estimator performs especially well when the errors are skewed, while another partially adaptive estimator and RLS perform particularly well when the errors are extremely leptokurtotic. In comparison with RLS, partially adaptive estimators …

Metrics For Evaluating Human-Robot Interactions, Michael A. Goodrich, Dan R. Olsen Jr.

Faculty Publications

Metrics for evaluating the quality of a human-robot interface are introduced. The autonomy of a robot is measured by its neglect time. The robot attention demand metric measures how much of the user’s attention is involved with instructing a robot. The free-time and fan-out metrics are two ways to measure this demand. Each of them leads to estimates of the interaction effort. Reducing interaction effort without diminishing task effectiveness is the goal of human-robot interaction design.

Automated Rating Of Esl Essays, Deryle W. Lonsdale, Diane Strong-Krause

Faculty Publications

To date, traditional NLP parsers have not been widely successful in TESOLoriented applications, particularly in scoring written compositions. Re-engineering such applications to provide the necessary robustness for handling ungrammatical English has proven a formidable obstacle. We discuss the use of a nontraditional parser for rating compositions that attenuates some of these difficulties. Its dependency-based shallow parsing approach provides significant robustness in the face of language learners’ ungrammatical compositions. This paper discusses how a corpus of L2 essays for English was rated using the parser, and how the automatic evaulations compared to those obtained by manual methods. The types of modifications …

Level Oriented Formal Model For Asynchronous Circuit Verification And Its Efficient Analysis Method, Eric G. Mercer, Tomoya Kitai, Chris Myers, Yusuke Oguro, Tomohiro Yoneda

Faculty Publications

Using a level-oriented model for verification of asynchronous circuits helps users to easily construct formal models with high readability or to naturally model datapath circuits. On the other hand, in order to use such a model on large circuits, techniques to avoid the state explosion problem must be developed. This paper first introduces a level-oriented formal model based on time Petri nets, and then proposes its partial order reduction algorithm that prunes unnecessary state generation while guaranteeing the correctness of the verification.

Controlling Laser High-Order Harmonic Generation Using Weak Counter-Propagating Light, Sergei Leonidovich Voronov

Theses and Dissertations

Laser high-order harmonic generation in the presence of relatively weak interfering light is investigated. The interfering pulses intersect the primary harmonic-generating laser pulse at the laser focus. The interfering light creates a standing intensity and phase modulation on the field, which disrupts microscopic phase matching and shuts down local high harmonic production. Suppression of the 23rd harmonic (by two orders of magnitude) is observed when a counter-propagating interfering pulse of light is introduced. A sequence of counter-propagating pulses can be used to shut down harmonic production in out-of-phase zones of the generating volume to achieve quasi phase matching. Harmonic emission …

Biaxial Strain-Modified Valence And Conduction Band Offsets Of Zinc-Blende Gan, Gap, Gaas, Inn, Inp, And Inas, And Optical Bowing Of Strained Epitaxial Ingan Alloys, Gus L. W. Hart, P. R. C. Kent, Alex Zunger

Faculty Publications

Using density-functional calculations, we obtain the (001) biaxial strain dependence of the valence and conduction band energies of GaN, GaP, GaAs, InN, InP, and InAs. The results are fit to a convenient-to-use polynomial and the fits provided in tabular form. Using the calculated biaxial deformation potentials in large supercell empirical psuedopotential calculations, we demonstrate that epitaxial strain reduces the InGaN alloy bowing coefficient compared to relaxed bulk alloys.

Coordinated Target Assignment And Intercept For Unmanned Air Vehicles, Erik P. Anderson, Randal W. Beard, Michael A. Goodrich, Timothy W. Mclain

Faculty Publications

This paper presents an end-to-end solution to the cooperative control problem represented by the scenario where unmanned air vehicles (UAVs) are assigned to transition through known target locations in the presence of dynamic threats. The problem is decomposed into the subproblems of: 1) cooperative target assignment; 2) coordinated UAV intercept; 3) path planning; 4) feasible trajectory generation; and 5) asymptotic trajectory following. The design technique is based on a hierarchical approach to coordinated control. Simulation results are presented to demonstrate the effectiveness of the approach.

Statistical Cataloging Of Archival Data For Luminosity Class Iv-V Stars - Ii. The Epoch 2001 [Fe/H] Catalog, B. J. Taylor

Faculty Publications

This paper describes the derivation of an updated statistical catalog of metallicities. The stars for which those metallicities apply are of spectral types F, G, and K, and are on or near the main sequence. The input data for the catalog are values of [Fe/H] published before 2002 February and derived from lines of weak and moderate strength. The analyses used to derive the data have been based on one-dimensional LTE model atmospheres. Initial adjustments which are applied to the data include corrections to a uniform temperature scale which is given in a companion paper (see Taylor 2003). After correction, …

Statistical Cataloging Of Archival Data For Luminosity Class Iv-V Stars, B. J. Taylor

Faculty Publications

This paper is one of a pair in which temperatures and metallicity catalogs for class IV-V stars are considered. The temperature catalog described here is derived from a calibration based on stellar angular diameters. If published calibrations of this kind are compared by using color-index transformations, temperature-dependent differences among the calibrations are commonly found. However, such differences are minimized if attention is restricted to calibrations based on Johnson V-K. A calibration of this sort from Di Benedetto (1998) is therefore tested and adopted. That calibration is then applied to spectroscopic and photometric data, with the latter predominating. Cousins R-I photometry …

Development And Design Of Constant-Force Mechanisms, Brent Lewis Weight

Theses and Dissertations

This thesis adds to the knowledge base of constant-force mechanisms (CFMs). It begins by reviewing past work done in the area of CFMs and then develops new nondimensionalized parameters that are used to simplify the calculations required to design a CFM. Comparison techniques are then developed that utilize these non-dimensionalized parameters to compare mechanisms based on stiffnesses, percent constant-force, actual lengths, normal displacements, and feasible design orientations. These comparison techniques are then combined with optimization to define new mechanisms with improved performance and range of capabilities. This thesis also outlines a design process, methods to identify mechanisms that are suitable …

A Theoretical Framework For The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo, Timothy Singer

Faculty Publications

The multicast address allocation problem requires Internet domains to allocate unique addresses to multicast applications from a globally-shared space. We develop a theoretical framework for multicast allocation algorithms that is influenced by subcube allocation in hypercube computer systems. Based on this framework we derive complexity results for the address allocation problem and describe several new allocation algorithms that use a hypercube model for address representation.

Modeling The Multicast Address Allocation Problem, Daniel Zappala, Chris Gauthierdickey, Virginia Lo

Faculty Publications

To support IP multicast, domains must assign a unique multicast address to each application from a limited, globally-shared address space. We examine the performance of several classes of address allocation algorithms withln the context of the MASC architecture. This study is the first of its kind to model the generalized multicast address allocation problem and consider non-contiguous allocation algorithms. We find that prefix-based allocation outperforms our non-contiguous algorithm, despite the apparent advantages of non-contiguous allocation. We also verify the benefits of using worst-fit for new allocations.