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A New Framework For Qos Provisioning In Wireless Lans Using The P-Persistent Mac Protocol, Kiran Babu Anna 2010 University of Central Florida

A New Framework For Qos Provisioning In Wireless Lans Using The P-Persistent Mac Protocol, Kiran Babu Anna

Electronic Theses and Dissertations, 2004-2019

The support of multimedia traffic over IEEE 802.11 wireless local area networks (WLANs) has recently received considerable attention. This dissertation has proposed a new framework that provides efficient channel access, service differentiation and statistical QoS guarantees in the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e. In the first part of the dissertation, the new framework to provide QoS support in IEEE 802.11e is presented. The framework uses three independent components, namely, a core MAC layer, a scheduler, and an admission control. The core MAC layer concentrates on the channel access mechanism to improve the overall ...


Misalignment Induced Nodal Aberration Fields And Their Use In The Alignment Of Astronomical Telescopes, Tobias Schmid 2010 University of Central Florida

Misalignment Induced Nodal Aberration Fields And Their Use In The Alignment Of Astronomical Telescopes, Tobias Schmid

Electronic Theses and Dissertations, 2004-2019

Following the foundation of aberration theory for rotationally symmetric optical systems established by Seidel, Schwarzschild, Burch, Conrady, Buchdahl, and in its most useful form H.H. Hopkins, Shack, Buchroeder, Thompson, and Rogers developed a vectorial form of the wave aberration theory that enables addressing optical systems without symmetry. In this research, a vectorial theory is utilized and extended for the alignment of two- and three-mirror astronomical telescopes, including the effects of pointing changes and astigmatic figure errors. Importantly, it is demonstrated that the vectorial form of aberration theory, also referred to as nodal aberration theory, not only provides valuable insights ...


Dft Study Of Geometry And Energetics Of Transition Metal Systems, Satyender Goel 2010 University of Central Florida

Dft Study Of Geometry And Energetics Of Transition Metal Systems, Satyender Goel

Electronic Theses and Dissertations, 2004-2019

This dissertation focuses on computational study of the geometry and energetics small molecules and nanoclusters involving transition metals (TM). These clusters may be used for various industrial applications including catalysis and photonics. Specifically, in this work we have studied hydrides and carbides of 3d-transition metal systems (Sc through Cu), small nickel and gold clusters. Qualitatively correct description of the bond dissociation is ensured by allowing the spatial and spin symmetry to break. We have tested applicability of new exchange-correlation functional and alternative theoretical descriptions (spin-contamination correction in broken symmetry DFT and ensemble Kohn-Sham (EKS)) as well. We studies TM hydrides ...


Structural, Electronic, Vibrational And Thermodynamical Properties Of Surfaces And Nanoparticles, Handan Yildirim 2010 University of Central Florida

Structural, Electronic, Vibrational And Thermodynamical Properties Of Surfaces And Nanoparticles, Handan Yildirim

Electronic Theses and Dissertations, 2004-2019

The main focus of the thesis is to have better understanding of the atomic and electronic structures, vibrational dynamics and thermodynamics of metallic surfaces and bi-metallic nanoparticles (NPs) via a multi-scale simulational approach. The research presented here involves the study of the physical and chemical properties of metallic surfaces and NPs that are useful to determine their functionality in building novel materials. The study follows the 'bottom-up' approach for which the knowledge gathered at the scale of atoms and NPs serves as a base to build, at the macroscopic scale, materials with desired physical and chemical properties. We use a ...


The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman 2010 University of Central Florida

The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman

Electronic Theses and Dissertations, 2004-2019

This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in ...


Universality In Algorithmic Self-Assembly, Scott Summers 2010 Iowa State University

Universality In Algorithmic Self-Assembly, Scott Summers

Graduate Theses and Dissertations

Tile-based self-assembly is a model of "algorithmic crystal growth" in which square "tiles" represent molecules that bind to each other via specific and variable-strength bonds on their four sides, driven by random mixing in solution but constrained by the local binding rules of the tile bonds. In the late 1990s, Erik Winfree introduced a discrete mathematical model of DNA tile assembly called the abstract Tile Assembly Mode. Winfree proved

that the Tile Assembly Model is computationally universal, i.e., that any Turing machine can be encoded into a finite set of tile types whose self-assembly simulates that Turing machine. In ...


Improving Probabilistic Ensemble Forecasts Of Convection Through The Application Of Qpf-Pop Relationships, Christopher John Schaffer 2010 Iowa State University

Improving Probabilistic Ensemble Forecasts Of Convection Through The Application Of Qpf-Pop Relationships, Christopher John Schaffer

Graduate Theses and Dissertations

Quantitative precipitation forecasts provide an accumulated precipitation amount for a given

time period, and accurate forecasts depend on the correct prediction of areal coverage,

timing, and intensity of precipitation. These forecasts are important to a variety of people for

many different purposes, so expressing a likelihood of precipitation is also useful. Most

simply, probabilities of precipitation are determined by considering the percentage of

ensemble members forecasting precipitation greater than a specified threshold amount.

Probabilities of precipitation can also be formed from quantitative precipitation forecasts

through statistical post-processing. Past research has shown that there are many ways to

post-process precipitation data ...


Evaluating And Understanding The Role Of Convective Processes In General Circulation Model Simulations Of The Madden-Julian Oscillation, Liping Deng 2010 Iowa State University

Evaluating And Understanding The Role Of Convective Processes In General Circulation Model Simulations Of The Madden-Julian Oscillation, Liping Deng

Graduate Theses and Dissertations

Weak temporal variability in tropical climate such as the Madden-Julian Oscillation (MJO) is one of the outstanding deficiencies in numerical weather prediction (NWP) models and coupled general circulation models (GCMs), which have beleaguered the model developer and user communities for years. The representation of convection, cloud and radiation processes has long been recognized as one of the major problems responsible for these deficiencies in climate models. Recently, with the improvement made to the convection scheme, the Iowa State University (ISU) GCM, which is based on the NCAR Community Climate Model version 3 (CCM3), is able to simulate many features of ...


Positive Solutions For A System Of Singular Second Order Nonlocal Boundary Value Problems, Naseer Ahmad Asif, Paul W. Eloe, Rahmat Ali Khan 2010 National University of Sciences and Technology, Rawalpindi, Pakistan

Positive Solutions For A System Of Singular Second Order Nonlocal Boundary Value Problems, Naseer Ahmad Asif, Paul W. Eloe, Rahmat Ali Khan

Mathematics Faculty Publications

Sufficient conditions for the existence of positive solutions for a coupled system of nonlinear nonlocal boundary value problems of the type (see PDF for details) are obtained. The nonlinearities (see PDF) are continuous and may be singular at t = 0, t = 1, x = 0, or y = 0. … An example is provided to illustrate the results.


Quantifiable Non-Functional Requirements Modeling And Static Verification For Web Service Compositions, Hongyu Sun 2010 Iowa State University

Quantifiable Non-Functional Requirements Modeling And Static Verification For Web Service Compositions, Hongyu Sun

Graduate Theses and Dissertations

As service oriented architectures have become more widespread in industry, many complex web services are assembled using independently developed modular services from different vendors. Although the functionalities of the composite web services are ensured during the composition process, the non-functional requirements (NFRs) are often ignored in this process. Since quality of services plays a more and more important role in modern service-based systems, there is a growing need for effective approaches to verifying that a composite web service not only offers the required functionality but also satisfies the desired NFRs.

Current approaches to verifying NFRs of composite services (as opposed ...


Comparison Of Encoding Schemes For Symbolic Model Checking Of Bounded Petri Nets, Nishtha Arora 2010 Iowa State University

Comparison Of Encoding Schemes For Symbolic Model Checking Of Bounded Petri Nets, Nishtha Arora

Graduate Theses and Dissertations

Petri nets are a graph based formalism used for modelling concurrent systems. Binary Decision Diagrams or Multi-Valued Decision Diagrams can be used in the analysis of systems modelled by Petri nets. An encoding scheme is required to be able to map the Petri net state to decision diagram values. Various encodings like One-hot scheme, logarithmic scheme and Mdd scheme exist for this purpose. This thesis compares the performance of the existing encodings based on time and space taken to represent and analyze the system modelled as Petri net. It also introduces and compares a new encoding scheme called k-hot encoding ...


Development And Application Of Qm/Mm Methods To Study The Solvation Effects And Surfaces, Pooja Arora 2010 Iowa State University

Development And Application Of Qm/Mm Methods To Study The Solvation Effects And Surfaces, Pooja Arora

Graduate Theses and Dissertations

The dissertation consists of the development and application of QM/MM methods to study the solvation effects and surfaces. The dissertation illustrates the methodology of the interface of the EFP method with the configuration interaction with single excitations (CIS) method to study solvent effects in excited states. The solvation effects have been studied on the adiabatic electron affinity of the hydroxyl radical in aqueous solution and in micro-solvated clusters using a QM/EFP method. A hybrid QM/MM embedded cluster model (SIMOMM) has been implemented to study the etching and diffusion of atomic oxygen on a reconstructed Si(100)-2X1 ...


Historical Vegetation Reconstruction Using Spatial Modeling On Pre-Euro-American Data To Inform Ecosystem Restoration In The Driftless Area Of The U.S. Midwest, Kumudan Grubh 2010 Iowa State University

Historical Vegetation Reconstruction Using Spatial Modeling On Pre-Euro-American Data To Inform Ecosystem Restoration In The Driftless Area Of The U.S. Midwest, Kumudan Grubh

Graduate Theses and Dissertations

The potential future outcomes of ecological restoration and management activities can be partially understood by investigating reference conditions and historical processes that contributed to the variability of past ecosystems. Reconstructing pre-Euro-American vegetation from Public Land Survey (PLS) records provides spatially precise and extensive reference information from which such variability estimates can be developed. We thus mapped pre-Euro-American vegetation cover within the Driftless Area of the U.S. Midwest using PLS records. Our mapping employed a four step process. First, trees ambiguously designated by the Public Land surveyors were identified to species using logistic regression models. Next, conditionally specified regression models ...


Spectrally Narrowed Leaky Waveguide Edge Emission And Transient Electroluminescent Dynamics Of Oleds, Zhengqing Gan 2010 Iowa State University

Spectrally Narrowed Leaky Waveguide Edge Emission And Transient Electroluminescent Dynamics Of Oleds, Zhengqing Gan

Graduate Theses and Dissertations

There are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs.

Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication.

The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is ...


Synthesis And Reactivity Of Alpha-Azido Acylals, Gretchen Bell 2010 Andrews University

Synthesis And Reactivity Of Alpha-Azido Acylals, Gretchen Bell

Honors Theses

alpha-Azido -Azido acylals are a novel combination of azide (N3) and acylal [R-C(OOCR)2] functional groups. Since these compounds are new chemical entities, little is known in the chemical literature about their physical, chemical, and biological properties. This synthetic methodology investigation sought to (1) develop a one-pot, two reaction method for preparing alpha-azido acylals and (2) investigate the chemical reactivity of alpha-azido acylals with phosphine reagents. Progress has been made and will be discussed regarding both the synthesis and reactivity of alpha-azido acylals. This work developed methods and processes that will have significant impact in our broader objective of ...


Toward Regional Climate Services The Role Of Noaa’S Regional Climate Centers, Arthur T. DeGaetano, Timothy J. Brown, Steven D. Hilberg, Kelly Redmond, Kevin Robbins, Peter Robinson, Martha Shulski, Marjorie McGuirk 2010 Cornell University

Toward Regional Climate Services The Role Of Noaa’S Regional Climate Centers, Arthur T. Degaetano, Timothy J. Brown, Steven D. Hilberg, Kelly Redmond, Kevin Robbins, Peter Robinson, Martha Shulski, Marjorie Mcguirk

Papers in Natural Resources

A comprehensive national climate services strategy requires the infrastructure, operational services, and applied research activities that have characterized the Regional Climate Center Program since its inception.


Preparation And Characterization Of Pt/Γ-Al2o3 Model Catalyst On Nial Alloy, Zhongfan Zhang, Long Li, Lin-Lin Wang, Sergio I. Sanchez, Ross V. Grieshaber, Qi Wang, Duane D. Johnson, Anatoly I. Frenkel, Ralph G. Nuzzo, Judith C. Yang 2010 University of Pittsburgh

Preparation And Characterization Of Pt/Γ-Al2o3 Model Catalyst On Nial Alloy, Zhongfan Zhang, Long Li, Lin-Lin Wang, Sergio I. Sanchez, Ross V. Grieshaber, Qi Wang, Duane D. Johnson, Anatoly I. Frenkel, Ralph G. Nuzzo, Judith C. Yang

Duane D. Johnson

Numerous studies of heterogeneous catalysis systems clearly demonstrate that the metal nanoparticle (NPs)/support interaction is significant in determining the catalytic chemistry. Theoretical simulations have been performed to understand the metal/support interactions [1,2]. For example, theorists discovered that electronic and oxygen defects of γ-Al2O3 anchor the active particles [1]. Platinum NPs dispersed on γ-alumina is one of the most widely used heterogeneous catalysts and Pt performs extremely well as a catalyst for the oxygen-reduction reaction used in fuel cell industries. Hence, we chose Pt/γ-Al2O3 as a model heterogeneous catalyst system to investigate the metal NPs/support interface ...


Interphase Energies Of Hcp Precipitates In Fcc Metals: A Density-Functional Theory Study In Al-Ag, Daniel Finkenstadt, Duane D. Johnson 2010 United States Naval Academy

Interphase Energies Of Hcp Precipitates In Fcc Metals: A Density-Functional Theory Study In Al-Ag, Daniel Finkenstadt, Duane D. Johnson

Duane D. Johnson

Density-functional theory (DFT) calculations of interphase boundary energies relevant to hexagonal-close-packed (hcp) γ-precipitate formation were performed within approximate unit cells that mirror the experimental conditions in face-centered-cubic (fcc) Al-Ag solid solutions. In Al-rich, fcc Al-Ag, γ precipitates are observed to form rapidly with large (300+) aspect ratios even though the Al stacking-fault energy is high (approximately 130 mJ/m2), which should suppress hcp ribbon formation according to standard arguments. Our DFT results show why high-aspect ratio plates occur and why previous estimates based on Wulff construction were orders of magnitude less than observed values. Using DFT, we obtain a Gibbs ...


New Policies Create A New Politics: Issues Of Institutional Design In Climate Change Policy, Henry Ergas 2010 University of Wollongong

New Policies Create A New Politics: Issues Of Institutional Design In Climate Change Policy, Henry Ergas

SMART Infrastructure Facility - Papers

Institutional design focuses on the task of providing accountability and effective monitoring of decision-making by bodies vested with the coercive powers of the state in a context where information is inherently limited, costly to acquire and asymmetrically distributed. This paper focuses on issues of institutional design in the context of climate change policy. It examines proposals advanced in the June 2008 Draft and Final Reports of the Garnaut Climate Change Review (‘Garnaut Reports’), and in the Government’s July 2008 Green Paper and December 2008 White Paper on the Carbon Pollution Reduction Scheme (‘Green and White Papers’) with respect to ...


Generating System Requirements For A Mobile Digital Evidence Collection System: A Preliminary Step Towards Enhancing The Forensic Collection Of Digital Devices, Ibrahim Baggili 2010 University of New Haven

Generating System Requirements For A Mobile Digital Evidence Collection System: A Preliminary Step Towards Enhancing The Forensic Collection Of Digital Devices, Ibrahim Baggili

Electrical & Computer Engineering and Computer Science Faculty Publications

Collecting digital devices in a forensically sound manner is becoming more critical since 80% of all cases have some sort of digital evidence involved in them (Rogers, 2006, p. 1) .The process of documenting and tagging digital devices is cumbersome and involves details that might not apply to other types of evidence, since each evidence item has unique physical characteristics (Hesitis & Wilbon, 2005, p. 17). The process becomes less manageable when a large number of digital devices are seized. This paper examines the information and issues investigators should be aware of when collecting digital devices at crime scenes. Furthermore, this ...


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