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2008

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Mathematical Model To Simulate A Hybrid Lighting System, Ahmad Abu Heiba Jan 2008

Mathematical Model To Simulate A Hybrid Lighting System, Ahmad Abu Heiba

UNLV Retrospective Theses & Dissertations

Hybrid solar lighting (HSL) technology is a relatively new technology to utilize natural sunlight along with the traditional electric lighting to light the interior spaces. HSL systems concentrate the sunlight onto a bundle of optical fibers. The optical fibers are routed into the interior space and coupled with cylindrical rods to diffuse the light. A lighting sensor modulates the amount of electric energy depending on the amount of natural light available; This study presents a simplified mathematical model to predict the output of the HSL system based on the amount of the available solar radiation. The model is verified via …

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A Cfd Model To Predict Pressure Loss Coefficient In Circular Ducts With A Motorized Damper, Pallavi Annabattula Jan 2008

A Cfd Model To Predict Pressure Loss Coefficient In Circular Ducts With A Motorized Damper, Pallavi Annabattula

UNLV Retrospective Theses & Dissertations

The pressure loss coefficient was determined for a circular duct with a circular damper using computational fluid dynamics. The CFD package Star-CD was used to predict the air flow and pressure distribution in the duct. A three dimensional computational fluid dynamics model was developed and simulated for five different positions of the damper ranging from partially opened position to completely opened position. The available standard k-epsilon model for high Reynolds number was used. The duct was also simulated for different flow conditions by varying the Reynolds number. The code generated the pressure drop across the damper, which was used to …

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Synthesis And Characterization Of Bulk And Thin Film Antimony-Selenium Phase Change Alloys, Nirup Bandaru Jan 2008

Synthesis And Characterization Of Bulk And Thin Film Antimony-Selenium Phase Change Alloys, Nirup Bandaru

UNLV Retrospective Theses & Dissertations

Phase change alloys have recently gained increasing attention due to their application in developing phase change random memory (PRAM) devices, as Flash memory based devices are rapidly approaching their technological limitations. The most dominant features of PRAM devices are its non-volatile nature, compatible with present day IC's manufacturing process, high density, fast operation, low power consumption etc; Devices built on binary alloys such as Antimony - Selenium (SbSe) exhibit certain superior properties such as fast operation, reduced power consumption, economical etc. compared to that of ternary alloy (GST). In order to understand this behavior in detail, bulk SbxSe 100-x (40 …

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The "White-Eyed" Eastern Towhee: A Molecular Assessment Of The Validity Of Pipilo Erythrophthalmus Alleni, Jeremy Shawn Batten Jan 2008

The "White-Eyed" Eastern Towhee: A Molecular Assessment Of The Validity Of Pipilo Erythrophthalmus Alleni, Jeremy Shawn Batten

UNLV Retrospective Theses & Dissertations

Exploring the factors that influence the distribution and diversification of organisms is essential to the field of evolutionary biology. Molecular examination across a species' distribution may result in the discovery of differentiated populations that, when interpreted in the context of past events (e.g. climate change), may elucidate the causal mechanisms. Comparative phylogeographic studies have revealed both similar and disparate genetic patterns among co-distributed organisms, although similar geographic patterns may differ greatly in temporal scale and thus in the magnitude of genetic differentiation. Studies of diverse taxa occurring across the southeastern United States have revealed several common patterns of intraspecific divergence …

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Exploratory Study Of Construction Safety Culture Through Systems Thinking, Charles J. Jr Benford Jan 2008

Exploratory Study Of Construction Safety Culture Through Systems Thinking, Charles J. Jr Benford

UNLV Retrospective Theses & Dissertations

Since its conception, in 1986 after the Chernobyl accident, the term "safety culture" has gained major popularity throughout many systems, especially the construction industry. Although this concept has gained much popularity over the course of two decades, it remains a heavily debated topic between advocates and skeptics for various reasons. Much of the skepticism is due to the failure of proponents of the concept to clearly define and provide an understanding of those factors that comprise what "safety culture" is, and how it can be achieved. A system (particularly a construction system) that possesses a safety culture is one in …

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Modeling The Unsaturated Zone At The Area 5 Radioactive Waste Management Site: Effects Of Climate Change And Vegetation On Flow Conditions, Amanda Marie Brandt Jan 2008

Modeling The Unsaturated Zone At The Area 5 Radioactive Waste Management Site: Effects Of Climate Change And Vegetation On Flow Conditions, Amanda Marie Brandt

UNLV Retrospective Theses & Dissertations

This thesis tests a series of potential future climate scenarios and associated environmental conditions that could result in the reversal of the present upward hydraulic gradient in the vadose zone at the Area 5 Radioactive Waste Management Site (RWMS) by implementing a one-dimensional model developed using the HYDRUS 1-D numerical modeling package. The research is divided into two phases. Phase I simulates the system from the Pleistocene to Holocene transition (approximately 13,000 years ago) to the present and is tested by independently varying precipitation, evaporation and transpiration rates. The results provide initial conditions for subsequent modeling under Phase II, which …

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Analyzing Cost And Schedule Growth In Public Works Projects, Leslie Ann Burns Jan 2008

Analyzing Cost And Schedule Growth In Public Works Projects, Leslie Ann Burns

UNLV Retrospective Theses & Dissertations

The final cost of a Public Works project can directly affect the number of projects that can be accomplished during a fiscal year. Many of the factors that determine the final cost of a project are not under the control of the Project Engineer. For example, there is the Contractor's productivity and manning levels, the weather, the price of materials, and the price of labor. Those items that are under the control of the Engineer are the quality of the drawings and specifications. Likewise, the time required to complete the project is dependent on complexity and quantity of work, site …

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Temperature And Silicon Effects On Tensile And Corrosion Behavior Of Chronium-Molybdenum Steel, Hanumantha Rao Chava Jan 2008

Temperature And Silicon Effects On Tensile And Corrosion Behavior Of Chronium-Molybdenum Steel, Hanumantha Rao Chava

UNLV Retrospective Theses & Dissertations

Martensitic P91 grade steels containing 0.48, 0.96, 1.28 and 1.77 weight percent (wt%) silicon (Si) have been tested for evaluation of their tensile properties at temperatures ranging from ambient to 550°C. The effect of activation using accelerator-driven electron beams on the room-temperature tensile properties of steels containing 0.48 and 1.28 wt% Si has also been investigated. The results indicate that all four heats of steel exhibited dynamic strain ageing at temperatures up to 400°C. The activated specimens showed enhanced tensile strength but reduced ductility with increasing activation time, indicating radiation hardening of the tested materials. The electrochemically-polarized specimens showed more …

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Numerical Analysis Of The Solid Particle Solar Receiver With The Influence Of An Air-Jet, Zhuoqi Chen Jan 2008

Numerical Analysis Of The Solid Particle Solar Receiver With The Influence Of An Air-Jet, Zhuoqi Chen

UNLV Retrospective Theses & Dissertations

This thesis develops and analyzes a three-dimensional computational model of a solid particle solar receiver (SPSR) for providing the heat source in a hydrogen production process using the sulfur iodine thermochemical water splitting reaction. In this reaction, a heat input of at least 850°C is necessary to keep high hydrogen production efficiency. Previous studies to achieve higher efficiency on a SPSR include changing particle materials, sizes, flow rates, and the geometry designs. The present study is concerned with the use of an air-jet in front of the open aperture and different operation conditions for the SPSR design optimization; The conceptual …

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Aerodynamic Optimization For Low Reynolds Number Flight Of A Solar Unmanned Aerial Vehicle, Louis Dube Jan 2008

Aerodynamic Optimization For Low Reynolds Number Flight Of A Solar Unmanned Aerial Vehicle, Louis Dube

UNLV Retrospective Theses & Dissertations

A study has been conducted to optimize the aerodynamics of a solar powered unmanned aerial vehicle for low Reynolds number flight. In this study, three areas of the airframe, namely the fuselage, wing-fuselage junction and wingtips, were analyzed, tested, evaluated and developed in an iterative design process. A numerical analysis method was employed to complete the aerodynamic study, the purpose of which was to minimize adverse flow conditions occurring near or about the aforementioned areas under most flight conditions and to maximize their aerodynamic usefulness. The results were benchmarked internally through the iterative process using the initial design as a …

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Determining Protein Biomarkers For Chemotherapeutic Drug Resistance In Breast Cancer, Shauna Durocher Jan 2008

Determining Protein Biomarkers For Chemotherapeutic Drug Resistance In Breast Cancer, Shauna Durocher

UNLV Retrospective Theses & Dissertations

Although there have been many research advances in the treatment and prevention of cancer, it remains a leading cause of death each year throughout the world. A major obstacle in the treatment of cancer is encountered when the cancer develops resistance to chemotherapeutic agents. To better understand resistance and identify biomarkers we propose to develop resistance in breast adenocarcinoma cancer cell lines, MDA-MB-231 and MCF-7, using common chemotherapeutic agents, doxorubicin and cisplatin. Microarray analysis will be preformed to identify over expression of proteins in these resistant lines. We hypothesize that genes which are over-expressed in a resistant cancer cell line …

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Sex And The Agricultural Transition: Dental Health Among Early Agricultural Females, Misty Fields Jan 2008

Sex And The Agricultural Transition: Dental Health Among Early Agricultural Females, Misty Fields

UNLV Retrospective Theses & Dissertations

This project analyzed dentition from a sample (n =142) of Early Agricultural period skeletons (B.C. 1600-200 A.D.) from the site of La Playa (SON F:10:3), Sonora, Mexico. Data was collected on pathology rates for dental caries and antemortem tooth loss (AMTL) to test the hypothesis that hormone-fluctuations associated with pregnancy increase dental pathology in females. Males and females were not found to have significant differences in caries rates. However, statistically significant differences in AMTL were found with females exhibiting more tooth loss than males ( p=.022). When compared across age categories, reproductive-age females had substantial increases in AMTL compared to …

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The Athletic, Academic, And Social Experiences Of Female Intercollegiate Team Sport Student-Athletes, Jason Michael Frank Jan 2008

The Athletic, Academic, And Social Experiences Of Female Intercollegiate Team Sport Student-Athletes, Jason Michael Frank

UNLV Retrospective Theses & Dissertations

Intercollegiate athletics at the Division I level in the United States have developed into highly publicized forms of entertainment and business (Hill, Burch-Ragan, & Yates, 2001), while often generating conflicts and dilemmas within universities when the goals of the athletic department clash with the goals of the school (Sperber, 1990; Zimbalist, 1999). In the middle of it all are student-athletes, young adults whose title combines two distinct roles into one. Balancing these roles can be difficult (Adler & Adler, 1987; Adler & Adler, 1990; Miller & Kerr, 2002; Miller & Kerr, 2003), but student-athletes who do balance their roles and …

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The Three Saras, Peter Golub Jan 2008

The Three Saras, Peter Golub

UNLV Retrospective Theses & Dissertations

There are two important foundations upon which my poetry stands: (1) Epistemologically I am an empiricist, not a realist; (2) my poetry is not empirical. That is, it operates in the realm of the thought experiment --the laboratory of the mind. This demon is a good analogy to how I write poetry. I usually get the urge to write a poem after thinking about a question, or a fact. In Maxwell's gedankenexperiment the fact is the second law of thermodynamics, and the question is: What if a demon partitioned the fast and slow molecules in a box?;Hence, there is this …

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The Effects Of Different Sport Mouth Guards On Respiration Rate And Tidal Volume At Sub-Maximal Exercise Level, Kevin Michael Finnegan Jan 2008

The Effects Of Different Sport Mouth Guards On Respiration Rate And Tidal Volume At Sub-Maximal Exercise Level, Kevin Michael Finnegan

UNLV Retrospective Theses & Dissertations

The problem directing this study was to determine differences between self-adapting sport mouthguards on respiratory rate and tidal volume during sub-maximal steady state exercise. The study was a within-subjects, repeated measures design. Fifteen male endurance trained subjects performed six sets of a 600 kpm workload for 10 min on a Monark cycle ergometer with five different mouthguard types (single sided, double sided, brain pad, gel or lip & mouth). Variables were analyzed by the ORCA metabolic system. The initial trial was a control trial with no mouthguard. The following five trials had five different mouthguard types used in a randomized …

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Self-Stabilizing Protocol For Anonymous Oriented Bi-Directional Rings Under Unfair Distributed Schedulers With A Leader, Chitwan Kumar Gupta Jan 2008

Self-Stabilizing Protocol For Anonymous Oriented Bi-Directional Rings Under Unfair Distributed Schedulers With A Leader, Chitwan Kumar Gupta

UNLV Retrospective Theses & Dissertations

We propose a self-stabilizing protocol for anonymous oriented bi-directional rings of any size under unfair distributed schedulers with a leader. The protocol is a randomized self-stabilizing, meaning that starting from an arbitrary configuration it converges (with probability 1) in finite time to a legitimate configuration (i.e. global system state) without the need for explicit exception handler of backward recovery. A fault may throw the system into an illegitimate configuration, but the system will autonomously resume a legitimate configuration, by regarding the current illegitimate configuration as an initial configuration, if the fault is transient. A self-stabilizing system thus tolerates any kind …

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The Impact Of User-Generated Contents In The Hotel Industry, Jun Mo Kwon Jan 2008

The Impact Of User-Generated Contents In The Hotel Industry, Jun Mo Kwon

UNLV Retrospective Theses & Dissertations

In many ways, the emergence of the Internet means consumers are now creating and spreading marketing information for various companies. Providers and consumers have become highly connected with the Internet environment. Therefore, user-generated-marketing information should be considered an important marketing tool in the hotel industry; Consumers can write reviews on travel websites or create personal blogs about their experiences. In addition, consumers post and upload pictures or movie files on the Internet, using advanced technologies. Consumers now can create and upload more visual materials, such as picture and video files, than in the past; Finally, this study focuses on encouraging …

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Poppe Culture, Jaq Greenspon Jan 2008

Poppe Culture, Jaq Greenspon

UNLV Retrospective Theses & Dissertations

We open in Venice Beach, with the hung-over Skids Poppe (30's). Skids, a former biker, is now a cult journalist for a variety of magazines. He still retains his dubious friends, one of which, Guantanamo Bey (30's), is an ex-military loafer who's sleeping on Skids' floor. Skids refers to Guantanamo as his "faithful sidekick." So, when another old friend, Bernie, calls Skids up and says he needs help, Skids and Guantanamo figure they'll get a free breakfast out of it at their favorite hang-out, the Sidewalk Cafe, a Venice Beach landmark; Skids says he knows better, but he still agrees …

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Simulation Of Optical Properties Of Quantum Dots, Anupam Kumar Jan 2008

Simulation Of Optical Properties Of Quantum Dots, Anupam Kumar

UNLV Retrospective Theses & Dissertations

Nanotechnology devices based on quantum dots have very interesting applications because of the unique characteristics that quantum dots exhibit. In addition to the very small size and operation almost at the speed of light, many important characteristics of quantum dots such as absorption and extinction can be exploited to design devices with a wide range of applications. The study of metallic quantum dots is also a very exciting and interesting field in engineering because of their immense application and relevance to Surface Enhanced Raman Spectroscopy (SERS); In this thesis, the variation in absorption spectra over a changing array of parameters …

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The Impact Of Conference Food Function Performance On Attendee Satisfaction And Behavior, Yoon-Young Lee Jan 2008

The Impact Of Conference Food Function Performance On Attendee Satisfaction And Behavior, Yoon-Young Lee

UNLV Retrospective Theses & Dissertations

A conference event with high attendance brings in economic resources to the destination city as well as hosting company. Its food functions in particular can be an effective tool to satisfy attendees and build good attendance, as it empowers an attendee's sensory memory of an event. Besides, nutritiously balanced food, which is sought-after these days, improves an attendee's learning ability. The purpose of this research was to identify factors that affect the attendee's perceived performance of and satisfaction with conference food function, and further, to understand an attendee's return intention based on the satisfaction level. It is concluded that the …

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Evaluate The Effectiveness Of The Speed Monitoring Display For Work Zones In Las Vegas, Xin Li Jan 2008

Evaluate The Effectiveness Of The Speed Monitoring Display For Work Zones In Las Vegas, Xin Li

UNLV Retrospective Theses & Dissertations

The objective of this thesis is to evaluate the performance of the SMD with different features of display sign: the size of the display sign, flashing the measured speed (with different flashing rate), and displaying warning message. In addition, this thesis will also evaluate the performance of the second SMD in a work zone. With these objectives, two testing sites, one on Cr-215 and the other on I-15, were chosen for this study. Six scenarios were developed which included (1) before condition (no SMDs in the work zone), (2) smaller sign, (3) larger sign without flashing, (4) larger sign with …

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True Reflections? An Assessment Of The Correlation Between Self-Reported Racial Identities And Craniometric Patterning, Rebecca V Lockwood Jan 2008

True Reflections? An Assessment Of The Correlation Between Self-Reported Racial Identities And Craniometric Patterning, Rebecca V Lockwood

UNLV Retrospective Theses & Dissertations

Modern anthropologists reject the notion that individuals can be assigned to clear-cut divisions of racial origins, yet this identification technique is a required practice in forensic settings. Forensic anthropologists study morphological features and craniometric values to assess the possible ancestry of an unidentified set of human remains. This ancestral assessment is subsequently translated into a "racial" description, as these categories are commonly used and understood by society; Race, however, is an artificial social construction, and racial categories fluctuate over time and space. Consequently, the forensic assessment of race based on cranial characteristics could significantly differ from an individual's self-assessment of …

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Energetics Of Insect Metamorphosis, Allison Brighton Merkey Jan 2008

Energetics Of Insect Metamorphosis, Allison Brighton Merkey

UNLV Retrospective Theses & Dissertations

During metamorphosis, Drosophila melanogaster pupae undergo a transformation which rearranges almost all larval tissues into an adult fly. During this time, it is surprising that pupae exhibit a U-shaped curve for metabolic rate, where metabolism decreases dramatically after pupariation and increases shortly before eclosion. Using temperature to offset the cost of development during metamorphosis, I demonstrate that the total energy cost for metamorphosis depends on temperature and associated differences in developmental time. Pupae tended to consume more triglycerides over the course of development at low and high temperatures. Changes in oxygen level did not affect the U-shaped curve of carbon …

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Diversity, Biogeography, And Geochemical Habitat Of Korarchaeota In Continental Hot Springs, Robin Lea Miller Jan 2008

Diversity, Biogeography, And Geochemical Habitat Of Korarchaeota In Continental Hot Springs, Robin Lea Miller

UNLV Retrospective Theses & Dissertations

Microorganisms have traditionally been characterized based on their morphology and physiology. However, this formula does not account for the importance of a microorganism's habitat, which is intimately linked to its physiology. The Korarchaeota comprise a deeply branching archaeal lineage that has proven to be difficult to isolate and, consequently, has remained uncharacterized until recently. The aim of this study was to evaluate the physicochemical and biogeographical distribution of Korarchaeota in hot springs of the Great Basin and Yellowstone National Park. Ninety-nine sediment samples were collected from hot springs with temperatures ranging from 40.7-94.3°C and pH ranging from 1.3-9.2, while recording …

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Passive Integrated Transponders In Gila Elegans: Location, Retention, Stress, And Mortality, Andrea Dee Montony Jan 2008

Passive Integrated Transponders In Gila Elegans: Location, Retention, Stress, And Mortality, Andrea Dee Montony

UNLV Retrospective Theses & Dissertations

Despite large-scale propagation and rearing efforts few of the critically endangered bonytail, Gila elegans, are recovered following release from hatcheries. This study tested the role of passive integrative transponder (PIT) tag loss and tagging associated stress and mortality in these low recoveries. Bonytail exhibited 98-100 percent tag retention regardless of insertion direction (ventral toward anterior and anterior toward ventral). Plasma cortisol levels were measured at 0, 0.5, 3, 6, 12, and 24 hours following PIT-tagging in fish held at three temperatures (12, 16, and 20°C) as an indicator of stress. Bonytail tagged at 16°C had significantly lower plasma cortisol levels …

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Caught In An Undertow Of Corruption: Stalled Democratization In Bosnia-Hercegovina, William Joseph Murray Jan 2008

Caught In An Undertow Of Corruption: Stalled Democratization In Bosnia-Hercegovina, William Joseph Murray

UNLV Retrospective Theses & Dissertations

Ethno-nationalism continues to be perceived by the international community as the primary source of Bosnia's political instability, and is seen as the leading cause of its stalled democratic consolidation. This thesis explores this premise, and questions whether international policy debates regarding Bosnia's future should continue to be framed in these terms; In-depth exploratory interviews were employed to examine political attitudes within a sample of thirty-one middle class Bosnian citizens. Findings suggest that middle class Bosnians are forming new political attitudes. Perceptions of corruption among Bosnia's middle class may be emerging as a barrier to democratic consolidation. Since a politically engaged …

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An Examination Of The Issues Of Non-String Teachers Teaching Strings, Melissa May Newbrey Jan 2008

An Examination Of The Issues Of Non-String Teachers Teaching Strings, Melissa May Newbrey

UNLV Retrospective Theses & Dissertations

The purpose of this study was to examine the training of non-string teachers who teach strings in Nevada secondary schools, as well as their approach to first-year string teaching issues. Sixty current string and non-string teachers across Nevada voluntarily responded to the survey portion of this study. Two non-string teachers teaching strings in Nevada and two string professors were chosen for the interview portion of this study. Results found that fewer non-string teachers were required to take string methods class than string teachers. Fewer non-string teachers compared to string teachers thought their string methods class was applicable to their first …

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Design And Control Of A Vibration Isolator Using A Biased Magnetorheological Elastomer, Saul Opie Jan 2008

Design And Control Of A Vibration Isolator Using A Biased Magnetorheological Elastomer, Saul Opie

UNLV Retrospective Theses & Dissertations

The objective of this work is to explore the capability of a Semi-Active (SA) elastomer and control techniques in the area of shock and vibration isolation. Typical passive isolation methods have short comings in meeting competing objectives. A specific problem is isolating electronic packages mounted to military vehicle walls from shock. Often passive elastomer based isolators are used. The ideal solution for shock isolation is a soft lightly damped isolator. However a soft lightly damped isolator will cause excessive sway during normal driving conditions. Further, vehicle dynamics during normal driving conditions are typically in the range of a few hertz, …

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Characterizing The Chipped Stone From Kritou Marottou Ais Yiorkis, Cyprus: Investigations Into The Cypro-Ppnb, Kasey Erin O'Horo Jan 2008

Characterizing The Chipped Stone From Kritou Marottou Ais Yiorkis, Cyprus: Investigations Into The Cypro-Ppnb, Kasey Erin O'Horo

UNLV Retrospective Theses & Dissertations

Kritou Marottou Ais Yiorkis represents the Middle Cypro-Pre-Pottery Neolithic B, a formative period in the prehistory of Cyprus. Many other aspects of the site lend to its significance, including the sites inland, upland location, presence of cattle, anomalous architecture, interesting botanical assemblage, and consistent yet distinctive chipped stone assemblage. The chipped stone from Ais Yiorkis was employed to examine economic choices and site use patterns. An overall characterization describes the assemblage, providing baseline data. Research questions investigate artifact variation, intra-site distribution, and inter-site compariSon The results have proven the assemblage to be contemporary, revealed a low degree of variation, very …

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A Study Of Monge Matrices With Applications To Scheduling, Revanth Pamballa Jan 2008

A Study Of Monge Matrices With Applications To Scheduling, Revanth Pamballa

UNLV Retrospective Theses & Dissertations

In this study of Monge properties I summarize a few aspects of the rich material based on these properties. Monge properties are related to the theory of convexity and just as convexity is important in classical Mathematics so is the theory of Monge properties important in Computer Science. In this thesis I will summarize a few aspects of Monge properties. I compare some of the different properties and show how that they all go back to Gaspard Monge's original ideas. I will highlight a number of new results in scheduling and show how Monge properties and Monge-like properties play a …

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