Physical Sciences and Mathematics Commons^™

A Comparison Of Training Algorithms For Dhp Adaptive Critic Neuro-Control, George G. Lendaris, Thaddeus T. Shannon, Andres Rustan

Complex Systems Faculty Publications and Presentations

A variety of alternate training strategies for implementing the Dual Heuristic Programming (DHP) method of approximate dynamic programming in the neuro-control context are explored. The DHP method of controller training has been successfully demonstrated by a number of authors on a variety of control problems in recent years, but no unified view of the implementation details of the method has yet emerged. A number of options are here described for sequencing the training of the Controller and Critic networks in DHP implementations. Results are given about their relative efficiency and the quality of the resulting controllers for two benchmark control …

Reconnaissance Survey Of Lewis And Clark On The Missouri National Recreational River, Nebraska And South Dakota, Anne P. Diffendal, Gary E. Moulton, Michael Shambaugh-Miller, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Part I
Lewis and Clark on the Middle Missouri by Gary E. Moulton
Appendix: Principal Sites and Events
Select Bibliography

Part II
Locating Lewis and Clark Sites
Site #1 Floyd's Bluff
Site #2 Gass's Election
Site #3 Ionia Volcano
Site #4 1804 Mouth of the Vermillion River
Site #5 Spirit Mound
Site #6 Shannon's Absence
Site #7 Calumet Bluff
Site #8 "Ancient Fortifications"
Site #9 Mouth of the Niobrara River
Site # 10 Old Baldy

The Weyr Characteristic, Helene Shapiro

Mathematics & Statistics Faculty Works

No abstract provided.

Legislating A Sustainable Land Ethic For New Zealand, Michèle D. Dominy

Pacific Studies

This article explores competing discourses of sustainability in New Zealand’s South Island. As active resource managers, high-country pastoralists’ conception of “country” contests predominant reductive and binary models of production/ conservation and economic resource/visual resource and suggests a more complicated dynamic between scientific and cultural paradigms of sustainability than has been acknowledged. This dynamic is captured in the internationally driven top-down concept of equitable sustainable land management with a dual commitment to both cultural and ecological diversity as defined locally, formulated as part of the United Nations Rio Declaration of 1992, agenda 21, chapter 13. I examine an emergent high-country “land …

Contributors: Vol 22 No. 3-4, The Jonathan Nāpela Center For Hawaiian And Pacific Islands Studies

Pacific Studies

Contributors list of Vol. 22 (1999): Pacific Studies Full Issue 3-4

Accounting For Change: Bringing Interdependence Into Defining Sustainability, Karen L. Nero

Pacific Studies

“Sustainability,” the key word of international development bodies currently intervening in the restructuring of the Marshall Islands economy, is defined within Western economic conceptualizations. I argue that such characterizations are incomplete: they fail to capture the full nature of the ongoing Marshallese economy by focusing too narrowly on transfers related to the Compact of Free Association and by their partial understanding of Marshallese food systems and easy dichotomies between imported and local foods. The segregation of external interventions by sector further distorts their possible impact. Structural imbalances within the Marshallese and other Pacific nations’ economies have been exacerbated by the …

Artisanal Coral Reef Fisheries And Sustainable Development: The Arno Atoll Fisheries Association, Jim Hess

Pacific Studies

The concept of sustainable development is inexact, requiring additional specification in application. How the subject of analysis is bounded will have consequences for understanding what is being sustained as well as for determining whether something is sustained. Here I examine a fisheries development project in the Marshall Islands. Shifting boundaries, I create three accounts of the project. In the first account, which focuses on resources and monetary cost and benefits, the project is clearly unsustainable. In the second account, focusing on international relations, the project sustains the relations of power and dependency. In the third account, I suggest that evaluation …

Is Tonga's Mirab Economy Sustainable? A View From The Village And A View Without It, Mike Evans

Pacific Studies

The development implications of the now-classic MIRAB economic pattern for South Pacific microstates (with economies dominated by overseas remittances and foreign aid) have attracted considerable attention. Some scholars argue the MIRAB pattern is well entrenched and can be sustained with a minimum of undesirable social and economic outcomes. Others decry the acceptance of the dependency of South Pacific nations and argue for renewed effort toward the development of self-sustaining economies. I argue that the debate must directly address the underlying social relations that facilitate and shape migration and remittances. In Tonga, the movement of people from rural areas has wide-ranging …

Wiyn Open Cluster Study. Ii. Ubvri Ccd Photometry Of The Open Cluster Ngc 188, Ata Sarajedini, Ted Von Hippel, Vera Kozhurina-Platais, Pierre Demarque

Publications

We present high-precision UBVRI CCD photometry of the old open cluster NGC 188. Our color-magnitude diagram extends from near the red giant branch tip to as faint as ~5 mag below the main-sequence turnoff. From an analysis of these data along with published photometry for M67, we draw the following conclusions: (1) From the UBV two-color diagram, we find a reddening of E(B ̶ V) = 0.04 ± 0.02 for M67 and E(B ̶ V) = 0.09 ± 0.02 for NGC 188. (2) Based on main-sequence fitting to solar abundance isochrones, the distance moduli …

Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing

Mathematics and Statistics Faculty Publications

Pertussis (whooping cough) incidence in the United States has oscillated with a period of about four years since data was first collected in 1922. An infection with pertussis confers immunity for several years, but then the immunity wanes, so that reinfection is possible. A pertussis reinfection is mild after partial loss of immunity, but the reinfection can be severe after complete loss of immunity. Three pertussis transmission models with waning of immunity are examined for periodic solutions. Equilibria and their stability are determined. Hopf bifurcation of periodic solutions around the endemic equilibrium can occur for some parameter values in two …

Further Studies On Fire Retardant Polystyrene By Friedel–Crafts Chemistry, Zhitao Wang, David D. Jiang, Charles Wilkie, Jeffery W. Gilman

Chemistry Faculty Research and Publications

The combination of a copolymer of 4-vinylbenzyl alcohol and styrene with 2-ethylhexyldiphenylphosphate (DPP) and with metal chlorides has been studied by TGA, radiative gasification, Cone Calorimetry, and oxygen index measurements. Evidence is presented in support of a cross-linking reaction with the additives and the copolymer, which proceeds through a Friedel–Crafts mechanism. This approach reduces the peak heat release rate (HRR) by 60% as measured in the Cone Calorimeter. There is a significant reduction in the mass loss rate during the thermal degradation, and evidence of char formation is observed in the radiative gasification experiments.

Tga/Ftir: An Extremely Useful Technique For Studying Polymer Degradation, Charles A. Wilkie

Chemistry Faculty Research and Publications

Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, has been used to probe the degradation of several polymeric systems. These include poly(methyl methacrylate) in the presence of various additives, graft copolymers of acrylonitrile-butadiene-styrene and styrene-butadiene with sodium methacrylate and styrene with acrylonitrile, blends of styrene-butadiene block copolymers with poly(vinylphosphonic acid) and poly(vinylsulfonic acid), and cross-linked polystyrenes. Additives may interact with poly(methyl methacrylate) by coordination to the carbonyl oxygen to a Lewis acid and the subsequent transfer of an electron from the polymer chain to the metal atom or by the formation of a radical which can trap the degrading …

Computational Geometry Column 36, Joseph O'Rourke

Computer Science: Faculty Publications

Two results in "computational origami" are illustrated.

A Simplified Model Of Wound Healing - Ii: The Critical Size Defect In Two Dimensions, J. S. Arnold, John A. Adam

Mathematics & Statistics Faculty Publications

Recently, a one-dimensional model was developed which gives a reasonable explanation for the existence of a Critical Size Defect (CSD) in certain animals [1]. In this paper, we examine the more realistic two-dimensional model of a circular wound of uniform depth to see what modifications are to be found, as compared with the one-dimensional model, in studying the CSD phenomenon. It transpires that the range of CSD sizes for a reasonable estimate of parameter values is 1 mm-1 cm. More realistic estimates await the appropriate experimental data.

Local And Landscape Factors Affecting Nest Site Selection And Nest Success Of Burrowing Owls In Western Nebraska, Rebecca T. Ekstein

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

No abstract provided.

Microscopic Origins Of Heliclinic Phases In Smectic Liquid Crystals, Jonathan J. Stott, Rolfe G. Petschek

Faculty Scholarship

In a previous article [Phys. Rev. E 60, 1799 (1999)], the authors considered a model Landau free energy that explained the ferriclinic phases of chiral smectic liquid crystals as a series of short period helical modulations. In this paper we begin with a physically more realistic, more microscopic interlayer free energy and show how our previous work can be derived using only simple short-ranged interactions. We then discuss what additional information this provides about the Landau coefficients used previously to construct the phase diagram for the heliclinic phases of chiral smectic liquid crystals. Finally, we investigate a means for explicitly …

Off-Line Compression By Greedy Textual Substitution, Alberto Apostolico, Stefano Lonardi

Department of Computer Science Technical Reports

No abstract provided.

A Model For Active Techniques For Compressed Video Transmission, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Towards The Evaluation Of Netcentric Scientific Applications, Shanhani Markus, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

An Adaptable Network Architecture For Multimedia Traffic Management And Control, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

String Pattern Matching For A Deluge Survival Kit, Alberto Apostolico, Maxime Crochemore

Department of Computer Science Technical Reports

No abstract provided.

Experimental Evaluation Of Design Tradeoff In Specialized Virtual Machine For Multimedia Traffic In Active Networks, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Production Of The Subtropical Seagrass, Halodule Wrightii Aschers., In Lower Laguna Madre, Texas, Joseph L. Kowalski

Theses and Dissertations - UTB/UTPA

The autecology of shoal grass, Halodule wrightii Aschers., was studied at 1.2 m depth from June 1995 to February 1997 in Lower Laguna Madre (LLM), Texas. Halodule wrightii in LLM received about 47% surface irradiance, but otherwise displayed lower growth rates and biomass in nutrient-poor rhizosphere and water-column environments compared to H. wrightii populations in other Texas estuaries. High tissue N content and low C:N ratios belied low growth dynamics. Halodule wrightii in LLM is probably nutrient limited. A high nutrient demand by H. wrightii in a nutrient-poor environment may explain, in part, its gradual displacement by Thalassia testudinum and …

Evaluation Of Sampling Methodologies For Assessing Fish Species Richness In Ridge And Valley Streams In Chattanooga, Tennessee, Evan Robertson Crews

Masters Theses and Doctoral Dissertations

I evaluated the adequacy of different electrofishing approaches for estimating species richness in small Ridge and Valley streams. My study objectives were to determine the effects of the sampling season, reach length, habitat sequences surveyed, and sampling intensity on estimates of fish species richness. Fish assemblages were sampled at 18 sites across five streams in the Chattanooga, Tennessee area, May-June (spring) and July-August (summer) 1998. Reach lengths ranged from 103 to 278 m (30 to 61 times the mean stream width [MSW]). At each site, fish were collected using one or two backpack electrofishers within habitat-specific enclosures (riflle-run or pool). …

Effects Of Watershed Land Use On The Benthic Macroinvertebrate Assemblages In Ridge And Valley Streams In Chattanooga, Tennessee, Paul Leiper Freeman

Masters Theses and Doctoral Dissertations

A total of 20 sites in five Ridge and Valley streams located in Chattanooga, Tennessee were sampled May 8, 1998 to June 18, 1998 using quantitative and qualitative macroinvertebrate sampling techniques. All streams sampled were part of the Tennessee River drainage system and eventually contribute to Nickajack Reservoir. The 20 sites were second to fourth order streams with drainage areas of 3.8 to 46.9 (km2) and elevations of 195 to 232 (m). Sites with different percentages of agricultural, urbanized and forested land-use were selected to best evaluate the resulting impacts of urbanization and other anthropogenic activities on the invertebrate community …

Systemic Environmental Analysis Of The Legal Mechanisms For Controlling Air Pollution In The Las Vegas Valley, Richard Little

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study examines the air pollution control structure for the Las Vegas Valley. A System Dynamics computer model was created that represents the structure of the real world system for controlling air pollution, in order to examine how the current air pollution control system might behave in the future.

Mineral Paragenesis And Ore Fluids At The Turquoise Ridge Gold Deposit, Nevada, Michiko Shigehiro

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study, mineral assemblages and related fluid inclusions at the Turquoise Ridge Carlin-type gold deposit were examined to answer the following questions: (1) What is the ore-stage mineral paragenesis? (2) At what pressures and temperatures did the deposits form? (3) What are the sources of ore fluids?

Pyrite with gold, jasperoid quartz, stibnite, orpiment, realgar, and calcite were successively deposited at Turquoise Ridge. Microthermometric data and isotopic ratios of inclusion fluids in ore-related minerals indicate entrapment of multiple generations of fluids in pre-ore, ore-, and late-ore stage minerals. Primary fluid inclusions in an ore-stage jasperoid quartz crystal have salinities …

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …

Comparison Of One-Dimensional And Two-Dimensional Hydrodynamic Modeling Approaches For Red River Basin, Sajjad Ahmad, Slobodan P. Simonovic

Civil and Environmental Engineering and Construction Faculty Research

EXECUTIVE SUMMARY

A devastating flood in Red River valley in 1997 emphasized the need to study the flood control measures in the Red River basin using state of the art modeling tools. The Red River and its floodplains can be modeled using one-dimensional, quasi two-dimensional or fully two-dimensional hydrodynamic models. Each modeling approach has its own advantages and limitations. The main purpose of this report is a comparison between one-dimensional (or quasi two dimensional) and fully two-dimensional hydrodynamic modeling approaches for modeling floods in the Red River basin.

A two-dimensional hydrodynamic model, MIKE 21, coupled with Geographic Information System (GIS) …

Alteration Associated With Gold Deposition At The Getchell, Carlin-Type Gold Deposit, North-Central Nevada, Tracy Lynn Cail

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alteration at the Getchell deposit was examined to determine the effects of ore-bearing fluids on host lithologies and the relationship between K-bearing alteration minerals and Au deposition. The geochemistry of unaltered to highly altered and mineralized rocks from the Getchell deposit was quantified for 54 samples collected along 14 transects in calcareous siltstone, carbonaceous limestone, and a rhyodacitic dike. Each transect was collected along a single homogeneous bed that could be followed from visibly unaltered waste rock into high-grade ore.

Calculated elemental gains and losses record an increase in the concentrations of Au, Hg, Sb, Se, Si, Te, Tl, and …