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Articles 5881 - 5910 of 8341

Full-Text Articles in Physical Sciences and Mathematics

Role Of Bcl-2 Family Members To Promote Glucocorticoid –Induced Apoptosis By Mek Inhibitors In Leukemic Cells, Anila Rambal Apr 2009

Role Of Bcl-2 Family Members To Promote Glucocorticoid –Induced Apoptosis By Mek Inhibitors In Leukemic Cells, Anila Rambal

Theses and Dissertations

Glucocorticoids (GC) are common components of many chemotherapeutic regimens for lymphoid malignancies. GC-induced apoptosis involves an intrinsic BCL-2 family-regulated pathway. It has been shown that BIM (BCL-2 interacting mediator of cell death), a BH3-only pro-apoptotic protein, is up-regulated by dexamethasone (Dex) treatment in acute lymphoblastic leukemia (ALL) cells. Furthermore, BIM is inactivated by extracellular signal-regulated kinase (ERK)-mediated phosphorylation. We therefore hypothesized co-treatment with Dex and MEK/ERK inhibitors would promote apoptosis in ALL cells through BIM up-regulation and activation. We show here that a MEK inhibitor, PD184352 synergistically enhances Dex lethality in CCRF-CEM (T-ALL) cells. Co-treatment with Dex and PD184352 results …

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Patterns Of Abundance Across An Urban-Rural Gradient For Commonly Found Indigenous Arthropods, David Jones Apr 2009

Patterns Of Abundance Across An Urban-Rural Gradient For Commonly Found Indigenous Arthropods, David Jones

Theses and Dissertations

Abstract Proof of concept for a continuous environmental sampling methodology that employs common terrestrial arthropods as environmental samplers was tested by analyzing pitfall, malaise and black light captures over a six month period over a replicated urban-suburban-rural gradient in Central Virginia. All arthropods captured at the nine sites were identified and assigned to aquatic, vegetation, or soil groups based on their association with these microhabitats. To offset variability in arthropod life history patterns and species abundance within habitat types, arthropod categories based on presence/absence data over the six month period were constructed to provide for sampling reliability within each microhabitat …

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Progressive Spatial Networks, Samuel Curren Apr 2009

Progressive Spatial Networks, Samuel Curren

Theses and Dissertations

Digital street and trail maps are typically represented by an interconnected network of path segments. These spatial networks are used in map creation, route planning, and geo-location. Consumer GPS devices have become popular as a method of collecting data for use in spatial networks. Existing methods for creating spatial networks either require extensive hand editing or use inefficient algorithms that require re-computation when adding new data to an existing network. I demonstrate a method for creating and maintaining spatial networks that allows for incremental updates without complete re-computation. I also demonstrate how spatial limits on data set growth allows networks …

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Synthesis Of 2,4,5-Triaminocyclohexane Carboxylic Acid As A Novel 2-Deoxystreptamine Mimetic, Sarah Elizabeth Roberts Apr 2009

Synthesis Of 2,4,5-Triaminocyclohexane Carboxylic Acid As A Novel 2-Deoxystreptamine Mimetic, Sarah Elizabeth Roberts

Theses and Dissertations

RNAs have become increasingly recognized as possible drug targets due to their involvement in important biochemical functions, as well as their unique but well-defined structures. Recently published crystal structures depict the binding of a series of aminoglycosides- or more specifically- 2-deoxystretamine (2-DOS), the most preserved central scaffold of aminoglycosides, to a conserved 5'-GU-3'region on their target RNAs. A novel unnatural γ-amino acid, 1, has been synthesized using 2-deoxystreptamine as a template through structure-based rational design. The unnatural amino acid has been designed to replace a glycosidic linkage with an amide bond, which may limit the promiscuous binding characteristics of aminoglycosides …

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State Of Secure Application Development For 802.15.4, Janell Armstrong Apr 2009

State Of Secure Application Development For 802.15.4, Janell Armstrong

Theses and Dissertations

A wireless sensor network consists of small, limited-resource embedded systems exchanging environment data and activating controls. These networks can be deployed in hostile environments to monitor wildlife habitats, implemented in factories to locate mobile equipment, and installed in home environments to optimize the use of utilities. Each of these scenarios requires network security to protect the network data. The IEEE 802.15.4 standard is designed for WSN communication, yet the standard states that it is not responsible for defining the initialization, distribution, updating, or management of network public keys. Individuals seeking to research security topics will find that there are many …

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Xprime: A Method Incorporating Expert Prior Information Into Motif Exploration, Rachel Lynn Poulsen Apr 2009

Xprime: A Method Incorporating Expert Prior Information Into Motif Exploration, Rachel Lynn Poulsen

Theses and Dissertations

One of the primary goals of active research in molecular biology is to better understand the process of transcription regulation. An important objective in understanding transcription is identifying transcription factors that directly regulate target genes. Identifying these transcription factors is a key step toward eliminating genetic diseases or disease susceptibilities that are encoded inside deoxyribonucleic acid (DNA). There is much uncertainty and variation associated with transcription factor binding sites, requiring these sites to be represented stochastically. Although typically each transcription factor prefers to bind to a specific DNA word, it can bind to different variations of that DNA word. In …

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Role Of Molecular Chaperones In G Protein B5-Regulator Of G Protein Signaling Dimer Assembly And G Protein By Dimer Specificity, Alyson Cerny Howlett Apr 2009

Role Of Molecular Chaperones In G Protein B5-Regulator Of G Protein Signaling Dimer Assembly And G Protein By Dimer Specificity, Alyson Cerny Howlett

Theses and Dissertations

In order for G protein signaling to occur, the G protein heterotrimer must be assembled from its nascent polypeptides. The most difficult step in this process is the formation of the Gβγ dimer from the free subunits since both are unstable in the absence of the other. Recent studies have shown that phosducin-like protein (PhLP1) works as a co-chaperone with the cytosolic chaperonin complex (CCT) to fold Gβ and mediate its interaction with Gγ. However, these studies did not address questions concerning the scope of PhLP1 and CCT-mediated Gβγ assembly, which are important questions given that there are four Gβs …

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Comparative Ecology And Conservation Status Of Procambarus (Pennides) Gibbus And Procambarus (Pennides) Versutus In Marion County, Georgia, Joann Chadwick Apr 2009

Comparative Ecology And Conservation Status Of Procambarus (Pennides) Gibbus And Procambarus (Pennides) Versutus In Marion County, Georgia, Joann Chadwick

Theses and Dissertations

Two crayfish species, whose conservation status was of concern, Procambarus (Pennides) gibbus Hobbs and Procambarus (Pennides) versutus Hagen, and one relatively common crayfish, Procambarus (Pennides) spiculifer LeConte were studied at nine creek sites in Marion County, Georgia. Major objectives of the yearlong study were to 1) compare the habitats of these species, looking for environmental differences that might account for their isolated distributions within the county and 2) assess the current conservation status of P. gibbus and P. versutus. Each study site was characterized by a one-time assessment of floodplain width, stream width, water velocity, stream depth and assessment of …

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Topics In Analytic Number Theory, Kevin James Powell Mar 2009

Topics In Analytic Number Theory, Kevin James Powell

Theses and Dissertations

The thesis is in two parts. The first part is the paper “The Distribution of k-free integers” that my advisor, Dr. Roger Baker, and I submitted in February 2009. The reader will note that I have inserted additional commentary and explanations which appear in smaller text. Dr. Baker and I improved the asymptotic formula for the number of k-free integers less than x by taking advantage of exponential sum techniques developed since the 1980's. Both of us made substantial contributions to the paper. I discovered the exponent in the error term for the cases k=3,4, and worked the case k=3 …

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Verifying Abstract Components Within Concrete Software Environments, Tonglaga Bao Mar 2009

Verifying Abstract Components Within Concrete Software Environments, Tonglaga Bao

Theses and Dissertations

In order to model check a software component which is not a standalone program, we need a model of the software which completes the program. This problem is important for software engineers who need to deploy an existing component into a new environment. The model is typically generated by abstracting the surrounding software environment in which the component will be executed. However, abstracting the surrounding software is a difficult and error-prone task, particularly when the surrounding software is a complex software artifact which can not be easily abstracted. In this dissertation, we present a new approach to the problem by …

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Frequency Diversity For Improving Synthetic Aperture Radar Imaging, Jawad L. Farooq Mar 2009

Frequency Diversity For Improving Synthetic Aperture Radar Imaging, Jawad L. Farooq

Theses and Dissertations

In this work, a novel theoretical framework is presented for using recent advances in frequency diversity arrays (FDAs). Unlike a conventional array, the FDA simultaneously transmits a unique frequency from each element in the array. As a result, special time and space properties of the radiation pattern are exploited to improve cross-range resolution. The idealized FDA radiation pattern is compared with and validated against a full-wave electromagnetic solver, and it is shown that the conventional array is a special case of the FDA. A new signal model, based on the FDA, is used to simulate SAR imagery of ideal point …

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Determining The Orbit Locations Of Turkish Airborne Early Warning And Control Aircraft Over The Turkish Air Space, Nebi Sarikaya Mar 2009

Determining The Orbit Locations Of Turkish Airborne Early Warning And Control Aircraft Over The Turkish Air Space, Nebi Sarikaya

Theses and Dissertations

The technology improvement affects the military needs of individual countries. The new doctrine of defense for many countries emphasizes detecting threats as far away as you can from your homeland. Today, the military uses both ground RADAR and Airborne Early Warning and Control (AEW&C) Aircraft. AEW&C aircraft has become vital to detect low altitude threats that a ground RADAR cannot detect because of obstacles on the earth. Turkey has ordered four AEW&C aircraft for her air defense system because of the lack of complete coverage by ground RADAR. This research provides optimal orbit locations that can be updated according to …

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Social Networking Website Users And Privacy Concerns: A Mixed Methods Investigation, Stephanie J. Mills Mar 2009

Social Networking Website Users And Privacy Concerns: A Mixed Methods Investigation, Stephanie J. Mills

Theses and Dissertations

Social networking websites are the fastest growing entity on the Internet. Users of social networking websites post personal information and pictures on these websites. Privacy and social networking websites has been previously studied, however, since those studies were conducted the rules for those websites have changed dramatically. A mixed methods approach was used in this study to examine what privacy concerns users of social networking websites have, whether it’s regarding information on their accounts or the pictures they have posted. This study also considered if there were common personality traits present in people with those concerns. A comparison of user …

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Exploitation Of Geographic Information Systems For Vehicular Destination Prediction, Richard T. Muster Mar 2009

Exploitation Of Geographic Information Systems For Vehicular Destination Prediction, Richard T. Muster

Theses and Dissertations

Much of the recent successes in the Iraqi theater have been achieved with the aid of technology so advanced that celebrated journalist Bob Woodward recently compared it to the Manhattan Project of WWII. Intelligence, Surveillance, and Reconnaissance (ISR) platforms have emerged as the rising star of Air Force operational capabilities as they are enablers in the quest to track and disrupt terrorist and insurgent forces. This thesis argues that ISR systems have been severely under-exploited. The proposals herein seek to improve the machine-human interface of current ISR systems such that a predictive battle-space awareness may be achieved, leading to shorter …

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Functionalization, Characterization, And Applications Of Diamond Particles, Modification Of Planar Silicon, And Chemoetrics Analysis Of Ms Data, Li Yang Mar 2009

Functionalization, Characterization, And Applications Of Diamond Particles, Modification Of Planar Silicon, And Chemoetrics Analysis Of Ms Data, Li Yang

Theses and Dissertations

In spite of the stablility (lack of reactivity) of diamond powder, I have developed a method for tethering alkyl chains and polymers to deuterium/hydrogen-terminated diamond. One method is through ether linkages via thermolysis of di-tert-amyl peroxide (DTAP). This reaction with DTAP has also been applied to grow polymers on the diamond surface. The other method is atom transfer radical polymerization (ATRP), which was applied to grow polystyrene at the surface of diamond. Both polystyrene-modified diamond and sulfonated polystyrene-modified diamond can be prepared by either method, and can be used for solid phase extraction. Diamond stationary phases are stable under basic …

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Bit-Error-Rate-Minimizing Channel Shortening Using Post-Feq Diversity Combining And A Genetic Algorithm, Gokhan Altin Mar 2009

Bit-Error-Rate-Minimizing Channel Shortening Using Post-Feq Diversity Combining And A Genetic Algorithm, Gokhan Altin

Theses and Dissertations

In advanced wireline or wireless communication systems, i.e., DSL, IEEE 802.11a/g, HIPERLAN/2, etc., a cyclic prefix which is proportional to the channel impulse response is needed to append a multicarrier modulation (MCM) frame for operating the MCM accurately. This prefix is used to combat inter symbol interference (ISI). In some cases, the channel impulse response can be longer than the cyclic prefix (CP). One of the most useful techniques to mitigate this problem is reuse of a Channel Shortening Equalizer (CSE) as a linear preprocessor before the MCM receiver in order to shorten the effective channel length. Channel shortening filter …

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Combined Visible And Infrared Video For Use In Wilderness Search And Rescue, Nathan D. Rasmussen Mar 2009

Combined Visible And Infrared Video For Use In Wilderness Search And Rescue, Nathan D. Rasmussen

Theses and Dissertations

Mini Unmanned Aerial Vehicles (mUAVs) have the potential to be a great asset to Wilderness Search and Rescue groups by providing a bird's eye view of the search area. These vehicles can carry a variety of sensors to better understand the world below. This paper proposes using both Infrared (IR) and Visible Spectrum cameras on a mUAV for Wilderness Search and Rescue. It details a method for combining the color and heat information from these two cameras into a single fused display to reduce needed screen space for remote field use. To align the video frames for fusion, a method …

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The First Attachment And Post-Functionalization Of Polybutadiene And Thio-Click Functionalized Polybutadiene On H-Terminated Si(111), Todd Devere Wickard Mar 2009

The First Attachment And Post-Functionalization Of Polybutadiene And Thio-Click Functionalized Polybutadiene On H-Terminated Si(111), Todd Devere Wickard

Theses and Dissertations

I report the attachment of polymers with pendant vinyl groups to hydrogen-terminated silicon(111) (Si(111)-H) under mild conditions. 1,2-addition polybutadiene (Mw 3200-3500) was attached to Si(111)-H at room temperature with visible light. I also report the partial functionalization, in solution, of 1,2-addition polybutadiene with various thiols using thiol-click chemistry. These compounds bind to Si(111)-H via visible light activation. The partially functionalized polybutadienes allow further functionalization at the surface through unreacted carbon-carbon double bonds. Surfaces were characterized with contact angle goniometry, spectroscopic ellipsometry, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM).

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Dynamic Network Formation Using Ant Colony Optimization, Steven C. Oimoen Mar 2009

Dynamic Network Formation Using Ant Colony Optimization, Steven C. Oimoen

Theses and Dissertations

Military and industry are moving toward every device being network enabled and connected for reliable availability of communication and information. To make this type of system a reality, the devices must be capable of forming a network topology on their own in a dynamic environment to ensure that the correct information reaches a desired location and on-time. This research presents three contributions for solving highly dynamic (i.e. drastic change within the network) Multi-commodity Capacitated Network Design Problems (MCNDPs) resulting in a distributed multi-agent network design algorithm. The first contribution incorporates an Ant Colony Optimization (ACO) algorithm Ant Colony System (ACS) …

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A Framework For Analyzing Biometric Template Aging And Renewal Prediction, John W. Carls Mar 2009

A Framework For Analyzing Biometric Template Aging And Renewal Prediction, John W. Carls

Theses and Dissertations

Biometric technology and systems are modernizing identity capabilities. With maturing biometrics in full, rapid development, a higher accuracy of identity verification is required. An improvement to the security of biometric-based verification systems is provided through higher accuracy; ultimately reducing fraud, theft, and loss of resources from unauthorized personnel. With trivial biometric systems, a higher acceptance threshold to obtain higher accuracy rates increase false rejection rates and user unacceptability. However, maintaining the higher accuracy rate enhances the security of the system. An area of biometrics with a paucity of research is template aging and renewal prediction, specifically in regards to facial …

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Forecasting Usaf Jp-8 Fuel Needs, Omer Saglam Mar 2009

Forecasting Usaf Jp-8 Fuel Needs, Omer Saglam

Theses and Dissertations

Oil is still one of the strategic energy resources for both the U.S. and the USAF today. Accurate oil prediction is important for the U.S. in order to improve the national strategy and the related budget concerns. Today, the U.S. is roughly importing 58% of its petroleum products. Moreover, in Fiscal Year (FY) 2007 the USAF total energy costs exceeded $6.9 billion. Aviation fuel accounted for approximately 81% of the total AF energy costs. Fluctuations in oil prices have huge impacts on the USAF’s JP-8 budgetary calculations. In order to handle this problem, the need for accurate forecasts arises. In …

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The Economic Impact Of A Radiological Dispersal Device (Rde), Michael T. Lebrun Mar 2009

The Economic Impact Of A Radiological Dispersal Device (Rde), Michael T. Lebrun

Theses and Dissertations

While it will not cause the devastation of a nuclear weapon, the radiological dispersal event (RDE) is particularly dangerous in that it has the potential to cause major economic disruptions. The purpose of this research was to develop a generalized methodology that can be used to assess economic impacts, resulting from a (RDE), occurring in any location and across any industry. Currently, there is no universal approach for measuring the costs or economic impacts on businesses, or a common framework for conducting an economic impact for a RDE. The objective of this research was to aid in the RDE response …

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An Evaluation Of Solar Air Heating At United States Air Force Installations, David S. Brown Mar 2009

An Evaluation Of Solar Air Heating At United States Air Force Installations, David S. Brown

Theses and Dissertations

The purpose of this research was to evaluate the use of solar air heating at U.S. Air Force installations. Specifically, this thesis analyzed Unglazed Transpired Collector (UTC) technology, more commonly known as SolarWalls®. This thesis sought to determine if UTC systems are an economically and environmentally viable technology which Air Force energy managers should include in their portfolio of alternative energy options. This research question was answered through the use of case studies and life-cycle cost analysis. Case studies were performed at various U.S. military installations which have already utilized UTC systems to provide a consolidated source of lessons learned. …

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A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly Mar 2009

A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly

Theses and Dissertations

Any entity operating in cyberspace is susceptible to debilitating attacks. With cyber attacks intended to gather intelligence and disrupt communications rapidly replacing the threat of conventional and nuclear attacks, a new age of warfare is at hand. In 2003, the United States acknowledged that the speed and anonymity of cyber attacks makes distinguishing among the actions of terrorists, criminals, and nation states difficult. Even President Obama’s Cybersecurity Chief-elect recognizes the challenge of increasingly sophisticated cyber attacks. Now through April 2009, the White House is reviewing federal cyber initiatives to protect US citizen privacy rights. Indeed, the rising quantity and ubiquity …

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Range Estimation Algorithm Comparison In 3-D Flash Ladar Data, Steven P. Jordan Mar 2009

Range Estimation Algorithm Comparison In 3-D Flash Ladar Data, Steven P. Jordan

Theses and Dissertations

Range estimation algorithms have been applied to Laser Detection and Ranging (LADAR) data to test for accuracy and precision. Data was acquired from Matlab® simulations and an experiment using the Advanced Scientific Concepts 3-D flash LADAR camera. Simulated LADAR data was based on a Gaussian pulse shape model with Poisson noise added. Simulations were performed to test range estimation algorithm performance with respect to waveform position within the range gate. The effectiveness of each algorithm is presented in terms of its average root mean square error and standard deviation in 1000 trials. The measured data experiment examined the effectiveness of …

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Blind Deconvolution Through Polarization Diversity Of Long Exposure Imagery, Steven P. James Mar 2009

Blind Deconvolution Through Polarization Diversity Of Long Exposure Imagery, Steven P. James

Theses and Dissertations

The purpose of the algorithm developed in this thesis was to create a post processing method that could resolve objects at low signal levels using polarization diversity and no knowledge of the atmospheric seeing conditions. The process uses a two-channel system, one unpolarized image and one linearly polarized image, in a GEM algorithm to reconstruct the object. Previous work done by Strong showed that a two-channel system using polarization diversity on short exposure imagery could produce images up to twice the diffraction limit. In this research, long exposure images were simulated and a simple Kolmogorov model used. This allowed for …

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Modeling Of Aircraft Deicing Fluid Induced Biochemical Oxygen Demand In Subsurface-Flow Constructed Treatment Wetlands, William J. Mclaughlin Mar 2009

Modeling Of Aircraft Deicing Fluid Induced Biochemical Oxygen Demand In Subsurface-Flow Constructed Treatment Wetlands, William J. Mclaughlin

Theses and Dissertations

Aircraft deicing is vital to safe operation in cold weather environments. Unfortunately, release of glycol-based aircraft deicing fluids (ADF) to waterways adjacent to airfields poses a significant environmental threat. The deicing fluids used at DoD airfields impart a high biochemical oxygen demand (BOD) when they enter waterways. The currently accepted conventional treatment is collection and transport of ADF-laden storm water to a publicly owned treatment works. The volume and BOD concentrations in the storm water often make this type of treatment impractical. Subsurface flow constructed treatment wetlands have been demonstrated to be effective in attenuating ADF-induced BOD. The models currently …

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Mitigating Insider Sabotage And Espionage: A Review Of The United States Air Force's Current Posture, Erika C. Leach Mar 2009

Mitigating Insider Sabotage And Espionage: A Review Of The United States Air Force's Current Posture, Erika C. Leach

Theses and Dissertations

The security threat from malicious insiders affects all organizations. Mitigating this problem is quite difficult due to the fact that (1) there is no definitive profile for malicious insiders, (2) organizations have placed trust in these individuals, and (3) insiders have a vast knowledge of their organization’s personnel, security policies, and information systems. The purpose of this research is to analyze to what extent the United States Air Force (USAF) security policies address the insider threat problem. The policies are reviewed in terms of how well they align with best practices published by the Carnegie Mellon University Computer Emergency Readiness …

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Operations-Focused Optimized Theater Weather Sensing Strategies Using Preemptive Binary Integer Programming, Andrew J. Geyer Mar 2009

Operations-Focused Optimized Theater Weather Sensing Strategies Using Preemptive Binary Integer Programming, Andrew J. Geyer

Theses and Dissertations

This thesis describes a method that optimally deploys weather sensors of all types in a battlefield environment. Gridded climatology models are used to determine an estimate for the weighted frequency of occurrence of operationally significant inclement weather events. That data is used to formulate a series of preemptive Binary Integer Linear Programs that maximize detection of expected operationally significant inclement weather occurrences within the constraints of feasibility of sensor deployment, sensor operational lifespan and the sensor’s ability to detect the operationally significant inclement weather elements. The preemptive Binary Integer Linear Programs are combined into a single objective function that maintains …

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Detecting Near-Earth Objects Using Cross-Correlation With A Point Spread Function, Anthony P. O'Dell Mar 2009

Detecting Near-Earth Objects Using Cross-Correlation With A Point Spread Function, Anthony P. O'Dell

Theses and Dissertations

This thesis describes a process to help discover Near-Earth Objects (NEOs) of larger than 140 meters in diameter from ground based telescopes. The process involves using Nyquist sampling rate to take data from a ground-based telescope and measuring the atmospheric seeing parameter, r0, at the time of data collection. r0 is then used to create a point spread function (PSF) for a NEO at the visual magnitude limit of the telescope and exposure time. This PSF is cross-correlated with the Nyquist sampling rate image from the telescope to reduce the noise and therefore increase the detection probability of …

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