188 research outputs found
Applications of Combinatorial Analysis to the Calculation of the Partition Function of the Ising Model
No full textThe research work discussed in this thesis investigated the application of combinatorics and graph theory in the analysis of the partition function of the Ising Model.
Chapter 1 gives a general introduction to the partition function of the Ising Model and the Feynman Identity in the language of graph theory.
Chapter 2 describes and proves combinatorially the Feynman Identity in the special case when there is only one vertex and multiple loops.
Chapter 3 digresses into the number of cycles in a directed graph, along with its application in the special case to derive the analytical expression of the number of non-periodic cycles with positive and negative signs.
Chapter 4 comes back to the general case of the Feynman Identity. The Feynman Identity is applied to several special cases of the graph and a combinatorial identity is established for each case.
Chapter 5 concludes the thesis by summarizing the main ideas in each chapter.</p
Microdebrider-assisted versus radiofrequency-assisted inferior turbinoplasty.
No full textObjectives: The study aimed to evaluate the long-term efficacy of microdebrider-assisted inferior turbinoplasty ( MATT) compared to radiofrequency-assisted inferior turbinoplasty (RAIT) for hypertrophic inferior turbinates. Study Design: Surgical outcomes were evaluated using the visual analogue scale, anterior rhinomanometry, and saccharin test results. Methods: From January 2001 to December 2006 inclusively, 120 patients with persistent allergic rhinitis, chronic nasal obstruction, and hypertrophic inferior turbinates were enrolled in this study , randomly classified, and underwent either MATT (n = 60) or RAIT. Ten patients who did not have any nasal discomfort served as normal controls. Assessments ( visual analogue scale, anterior rhinomanometry, and saccharin test) were conducted prior to surgery and 6 months, 1, 2, and 3 years subsequent to surgery. Results: Compared to preoperative values, the symptom scores ( nasal obstruction, sneezing, rhinorrhea, and snoring), mean total nasal resistance, and mean saccharin transit time all improved significantly at 6 months, 1, 2, and 3 years after surgery in MATT group (P < . 05 for all) . The same holds true for the RAIT group from 6 months up to 1 year (P < . 05 for all), but no improvements from 2 to 3 years after were noted. The parameters between the two groups did not significantly differ 6 months after surgery, but was noted after 1 to 3 years (P < .05 for all.) . Conclusion: MATT is more effective than BAIT at relieving nasal symptoms and decreasing total nasal resistance and saccharin transit time 1 to 3 years post-operatively in patients with persistent allergic rhinitis and who have substantial nasal obstruction
A Practical and Controllable Hair and Fur Model for Production Path Tracing
No full textWe present an energy-conserving fiber shading model for hair and fur that is efficient enough for path tracing. Our model adopts a near-field formulation to avoid the expensive integral across the fiber, accounts for all high order internal reflection events with a single lobe, and proposes a novel, closed-form distribution for azimuthal roughness based on the logistic distribution. Additionally, we derive, through simulation, a parameterization that relates intuitive user controls such as multiple-scattering albedo and isotropic cylinder roughness to the underlying physical parameters.Computer Graphics ForumRendering Techniques35
Improved Encoding for Compressed Textures
No full textFor the past few decades, graphics hardware has supported mapping a two dimensional image, or texture, onto a three dimensional surface to add detail during rendering. The complexity of modern applications using interactive graphics hardware have created an explosion of the amount of data needed to represent these images. In order to alleviate the amount of memory required to store and transmit textures, graphics hardware manufacturers have introduced hardware decompression units into the texturing pipeline. Textures may now be stored as compressed in memory and decoded at run-time in order to access the pixel data. In order to encode images to be used with these hardware features, many compression algorithms are run offline as a preprocessing step, often times the most time-consuming step in the asset preparation pipeline. This research presents several techniques to quickly serve compressed texture data. With the goal of interactive compression rates while maintaining compression quality, three algorithms are presented in the class of endpoint compression formats. The first uses intensity dilation to estimate compression parameters for low-frequency signal-modulated compressed textures and offers up to a 3X improvement in compression speed. The second, FasTC, shows that by estimating the final compression parameters, partition-based formats can choose an approximate partitioning and offer orders of magnitude faster encoding speed. The third, SegTC, shows additional improvement over selecting a partitioning by using a global segmentation to find the boundaries between image features. This segmentation offers an additional 2X improvement over FasTC while maintaining similar compressed quality. Also presented is a case study in using texture compression to benefit two dimensional concave path rendering. Compressing pixel coverage textures used for compositing yields both an increase in rendering speed and a decrease in storage overhead. Additionally an algorithm is presented that uses a single layer of indirection to adaptively select the block size compressed for each texture, giving a 2X increase in compression ratio for textures of mixed detail. Finally, a texture storage representation that is decoded at runtime on the GPU is presented. The decoded texture is still compressed for graphics hardware but uses 2X fewer bytes for storage and network bandwidth.Doctor of Philosoph
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ESSAYS ON MARKET INEFFICIENCIES ARISING FROM INFORMATION ASYMMETRY AND MARKET POWER
No full textThis dissertation comprises three chapters that empirically investigate various kinds of market inefficiencies arising from seller misbehaviors. The first two chapters focus on physicians' overtreatment in healthcare markets. A standard reputation system falls short of effectively curbing overtreatment due to the credence-good nature of such a market: patients cannot tell whether a high-cost treatment recommendation (versus a less costly and complex treatment) is necessary even after the service is completed. In the first chapter, I propose a novel solution to reinstate the function of reputation by combining a reputation mechanism with patient search for second opinions. I conduct a laboratory experiment to test this new mechanism. In the second chapter, motivated by newly-emerged public information, the aggregate count of each type of treatment provided by a health provider, I experimentally investigate whether such information could reduce overtreatment and replace patients’ reliance on costly searches in repeated interactions. In the third chapter, the focus shifts to market power in wholesale electricity markets. In this study, my co-author and I utilize nuclear refueling outages as a test for the exercise of market power by energy suppliers in the New England market during the years 2016-2018.Resource EconomicsDoctor of Philosophy (Ph.D.
An industrial analysis of the United States wine industry, world wine industry and China wine industry
No full textPlan BA series of industrial analysis were adapted on three different market fields. These analyses explored different market environments. In each analysis of market environment, the primary factors, such as consumers, competitions, government public, were described respectively. These descriptions include three basic contents: current situation, future situation, and implications. Generally, the current market overview and market segmentation were utilized to represent the current situations of consumers and competitions. The Technological forces, Economic forces, Socio-Culture forces and legal/Government forces were identified to determine the tendency of market. The analysis shows the landscape of Wine Business in the United States, the New and Old 4 wine World, and China, as well as described the path to penetrate the big and promising wine market—China Wine market
Access Control and Service-Oriented Architectures.
No full textAccess Control and Service-Oriented Architectures" investigates in which way logical access control can be achieved effectively, in particular in highly dynamic environments such as service-oriented architectures (SOA's). The author combines state-of-the-art best-practice and projects these onto the SOA. In doing so, he identifies strengths of current approaches, but also pinpoints weaknesses. These weaknesses are subsequently mitigated by introducing an innovative new framework called EFSOC. The framework is validated empirically and preliminary implementations are discussed.
Shooting for Accuracy
No full textAlthough researchers have questioned their coverage and accuracy, the media routinely are used as sources of data on mass murder in the United States. Databases compiled from media sources such as newspaper and network news programs include the New York Police Department\u27s Active Shooters file, the Brady Campaign Mass Casualty Shootings data set, and the Mother Jones database. Conversely, official crime data have been underutilized by researchers who study mass murder (for exceptions, see Duwe, 2007; Fox & Levin, 1998). In this study, we compare similarities and differences for mass murder cases in the United States as portrayed by selected mass media sources. Then, we turn our focus to a comparison of the Uniform Crime Reports\u27 (UCR) Supplementary Homicide Report (SHR) and the National Incident-Based Reporting System (NIBRS). Our primary focus is on mass murders involving four or more fatalities-not including the perpetrator-that have occurred between 2001 and 2010. Implications for enhancing the comprehensiveness and quality of mass murder data with the goal of increasing their usefulness for guiding prevention and risk mitigation efforts also are discussed. © 2013 SAGE Publications
ALT-C 2011 Abstracts
No full textThis is a PDF of the abstracts for all the sessions at the 2011 ALT conference. It is designed to be used alongside the online version of the conference programme. It was made public on 1 September, with a "topped and tailed" made live on 2 September
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