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A DERIVATION OF AN EMPIRICAL EQUATION FOR ESTIMATING THE ACOUSTICAL SHADOW ZONE LENGTH OF ROADWAY NOISE BARRIERS
Title
A DERIVATION OF AN EMPIRICAL EQUATION FOR ESTIMATING THE ACOUSTICAL SHADOW ZONE LENGTH OF ROADWAY NOISE BARRIERS.
Creator
Arner, Wayne, Wayson, Roger, University of Central Florida
Abstract / Description
The objective of this research was to derive an empirical equation that estimates the acoustical shadow zone length (SZL) of roadway noise barriers. The acoustical shadow zone is the area behind a noise barrier of reduced sound levels, generally to some stated level at or near background. The ability to predict the SZL can be used as a method to evaluate the performance, and possibly the design, of roadway noise barriers. The current federally required roadway noise model is the Federal...
Show moreThe objective of this research was to derive an empirical equation that estimates the acoustical shadow zone length (SZL) of roadway noise barriers. The acoustical shadow zone is the area behind a noise barrier of reduced sound levels, generally to some stated level at or near background. The ability to predict the SZL can be used as a method to evaluate the performance, and possibly the design, of roadway noise barriers. The current federally required roadway noise model is the Federal Highway Administration (FHWA) Traffic Noise Model (TNM). TNM uses insertion loss (IL) to evaluate the effectiveness of a barrier. Insertion loss is the difference in sound level between the "no barrier" and the "with barrier" case. One major limitation with TNM is that the reported IL does not take into account how background noise levels influence the mitigated sound levels. Background noise can be defined as the noise present at a barrier location in the absence of roadway noise. The shadow zone represents a region behind the noise barrier where the barrier is effective at reducing noise levels and takes into account how background noise affects the IL and thus the SZL. The inclusion of background noise becomes significant in evaluating barrier effectiveness because as the distance from the barrier increases, background noise begins to overtake roadway noise as the dominate noise source. The derivation of the empirical equation began by collecting in-situ noise measurements at 18 noise barrier locations across Florida. The measured noise data was supplemented by noise data obtained from computer modeling. After a sufficient quantity of measured and modeled IL data was obtained, a contour of equal IL (IL = 5 dB) was plotted for each barrier location. The area defined by the contour is called the shadow zone. All the SZLs were statistically compared to several variables that were expected to influence it. Regression modeling showed that the background noise level, noise barrier height, the distance from the roadway to the noise barrier, and percent of heavy truck traffic volume were statistically significant as useful predictors of SZL. Two empirical equations were derived, one from linear regression and one from polynomial regression, and are referred to as the Shadow Zone Equations.
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Date Issued
2006
Identifier
CFE0001464, ucf:47096
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001464
WAVELETS IN REAL-TIME RENDERING
Title
WAVELETS IN REAL-TIME RENDERING.
Creator
sun, weifeng, Mukherjee, Amar, University of Central Florida
Abstract / Description
Interactively simulating visual appearance of natural objects under natural illumination is a fundamental problem in computer graphics. 3D computer games, geometry modeling, training and simulation, electronic commerce, visualization, lighting design, digital libraries, geographical information systems, economic and medical image processing are typical candidate applications. Recent advances in graphics hardware have enabled real-time rasterization of complex scenes under artificial lighting...
Show moreInteractively simulating visual appearance of natural objects under natural illumination is a fundamental problem in computer graphics. 3D computer games, geometry modeling, training and simulation, electronic commerce, visualization, lighting design, digital libraries, geographical information systems, economic and medical image processing are typical candidate applications. Recent advances in graphics hardware have enabled real-time rasterization of complex scenes under artificial lighting environment. Meanwhile, pre-computation based soft shadow algorithms are proven effective under low-frequency lighting environment. Under the most practical yet popular all-frequency natural lighting environment, however, real-time rendering of dynamic scenes still remains a challenging problem. In this dissertation, we propose a systematic approach to render dynamic glossy objects under the general all-frequency lighting environment. In our framework, lighting integration is reduced to two rather basic mathematical operations, efficiently computing multi-function product and product integral. The main contribution of our work is a novel mathematical representation and analysis of multi-function product and product integral in the wavelet domain. We show that, multi-function product integral in the primal is equivalent to summation of the product of basis coefficients and integral coefficients. In the dissertation, we give a novel Generalized Haar Integral Coefficient Theorem. We also present a set of efficient algorithms to compute multi-function product and product integral. In the dissertation, we demonstrate practical applications of these algorithms in the interactive rendering of dynamic glossy objects under distant time-variant all-frequency environment lighting with arbitrary view conditions. At each vertex, the shading integral is formulated as the product integral of multiple operand functions. By approximating operand functions in the wavelet domain, we demonstrate rendering dynamic glossy scenes interactively, which is orders of magnitude faster than previous work. As an important enhancement to the popular Pre-computation Based Radiance Transfer (PRT) approach, we present a novel Just-in-time Radiance Transfer (JRT) technique, and demonstrate its application in real-time realistic rendering of dynamic all-frequency shadows under general lighting environment. Our work is a significant step towards real-time rendering of arbitrary scenes under general lighting environment. It is also of great importance to general numerical analysis and signal processing.
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Date Issued
2006
Identifier
CFE0001495, ucf:47079
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001495
Algorithms for Rendering Optimization
Title
Algorithms for Rendering Optimization.
Creator
Johnson, Jared, Hughes, Charles, Tappen, Marshall, Foroosh, Hassan, Shirley, Peter, University of Central Florida
Abstract / Description
This dissertation explores algorithms for rendering optimization realizable within a modern, complex rendering engine. The first part contains optimized rendering algorithms for ray tracing. Ray tracing algorithms typically provide properties of simplicity and robustness that are highly desirable in computer graphics. We offer several novel contributions to the problem of interactive ray tracing of complex lighting environments. We focus on the problem of maintaining interactivity as both...
Show moreThis dissertation explores algorithms for rendering optimization realizable within a modern, complex rendering engine. The first part contains optimized rendering algorithms for ray tracing. Ray tracing algorithms typically provide properties of simplicity and robustness that are highly desirable in computer graphics. We offer several novel contributions to the problem of interactive ray tracing of complex lighting environments. We focus on the problem of maintaining interactivity as both geometric and lighting complexity grows without effecting the simplicity or robustness of ray tracing. First, we present a new algorithm called occlusion caching for accelerating the calculation of direct lighting from many light sources. We cache light visibility information sparsely across a scene. When rendering direct lighting for all pixels in a frame, we combine cached lighting information to determine whether or not shadow rays are needed. Since light visibility and scene location are highly correlated, our approach precludes the need for most shadow rays. Second, we present improvements to the irradiance caching algorithm. Here we demonstrate a new elliptical cache point spacing heuristic that reduces the number of cache points required by taking into account the direction of irradiance gradients. We also accelerate irradiance caching by efficiently and intuitively coupling it with occlusion caching.In the second part of this dissertation, we present optimizations to rendering algorithms for participating media. Specifically, we explore the implementation and use of photon beams as an efficient, intuitive artistic primitive. We detail our implementation of the photon beams algorithm into PhotoRealistic RenderMan (PRMan). We show how our implementation maintains the benefits of the industry standard Reyes rendering pipeline, with proper motion blur and depth of field. We detail an automatic photon beam generation algorithm, utilizing PRMan shadow maps. We accelerate the rendering of camera-facing photon beams by utilizing Gaussian quadrature for path integrals in place of ray marching. Our optimized implementation allows for incredible versatility and intuitiveness in artistic control of volumetric lighting effects. Finally, we demonstrate the usefulness of photon beams as artistic primitives by detailing their use in a feature-length animated film.
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Date Issued
2012
Identifier
CFE0004557, ucf:49231
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004557
THE SHADOW RATE AND ITS RELATIONSHIP WITH LENDER AND BORROWER VARIABLES
Title
THE SHADOW RATE AND ITS RELATIONSHIP WITH LENDER AND BORROWER VARIABLES.
Creator
Irimia, Andrei, Aysun, Uluc, University of Central Florida
Abstract / Description
Since the federal funds rate reached the zero lower bound in late 2008, economists have been struggling to adapt their models to a long-term zero rate. Wu and Xia built upon previous research by Fischer Black to create a model for how the federal funds rate behaves during the ZLB period. In their model, the rate actually dips into the negative digits, which the actual federal funds rate does not do. The logic behind the model is that a negative shadow rate is a much better indicator of true...
Show moreSince the federal funds rate reached the zero lower bound in late 2008, economists have been struggling to adapt their models to a long-term zero rate. Wu and Xia built upon previous research by Fischer Black to create a model for how the federal funds rate behaves during the ZLB period. In their model, the rate actually dips into the negative digits, which the actual federal funds rate does not do. The logic behind the model is that a negative shadow rate is a much better indicator of true economic conditions while the current zero rate merely masks the actual economic reality. It is also easier to use the shadow rate for trend analysis purposes, since the shadow rate is flexible and changes while the federal funds rate remains artificially fixed at zero. Thus, this paper seeks to provide a comparison between the Shadow Rate, as defined by Wu and Xia, and how three key banking variables (leverage, profitability, and non-performing loans to total loans) react in response to the shadow rate, along with three control variables: real GDP growth, inflation, and the current account to GDP ratio. Regression will also be used to determine how three key borrower variables (S&P 500 Index, Credibility Consumer Distress Index, and the ratio of nonfinancial corporate business debt securities to total assets) interact with the shadow rate and the three control variables previously mentioned.
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Date Issued
2016
Identifier
CFH2000052, ucf:45528
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000052
Government Respect for Human Rights and their Relation to Shadow Economic Activity
Title
Government Respect for Human Rights and their Relation to Shadow Economic Activity.
Creator
Gahagan, Christopher, Mousseau, Demet, Marien, Daniel, Reynolds, Teddy, University of Central Florida
Abstract / Description
Shadow economic activity can have detrimental effects on many aspects of a society including trust in government policies, quality of public institutions, government revenues, and economic growth. Empirical studies have generally employed a rational actor approach and focused on economic factors. Most studies in this literature claim that when individuals do not receive the right economic stimuli from the government, it damages the relationship between individuals and the state and citizens...
Show moreShadow economic activity can have detrimental effects on many aspects of a society including trust in government policies, quality of public institutions, government revenues, and economic growth. Empirical studies have generally employed a rational actor approach and focused on economic factors. Most studies in this literature claim that when individuals do not receive the right economic stimuli from the government, it damages the relationship between individuals and the state and citizens opt to move into the shadow economy. A small but growing body of research, however, suggests that certain political factors can also lead to shadow economic activity because of a breakdown in the relationship between individuals and the state. Building on this growing body of research, this study investigates how governments' repression of human rights can play an important role in the growth of shadow economic activities. The empirical literature on human rights offer three main groups of human rights: Survival Rights (physical integrity), Women's Economic Rights, and Civil Liberties (i.e. freedom of speech). This study expects a similar pattern for all sectors of human rights, that when they are abused, citizens will react to those abuses by moving into the shadow economy because of the breakdown in the citizen-state relationship. Several multiple regression analyses are conducted for 150 countries from the years 1999 to 2011 to investigate if these different types of human rights had an impact on the levels of shadow economic activity. Results indicate that while Survival Rights and Women's Economic Rights have no statistically significant impact on the size of the shadow economy, the respect or abuse of citizens' Civil Liberties are statistically significant after the introduction of control variables. A possible reason for the difference in these findings might be that while the fear of reprisal of Survival Rights can work to deter shadow economic activity, repression of Civil Liberties may not create enough fear to deter it. Future research is necessary in this area to expand our knowledge on the political determinants of the size of the shadow economy as well as the creation of policies to combat its growth.
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Date Issued
2019
Identifier
CFE0007459, ucf:52691
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007459
REAL-TIME CINEMATIC DESIGN OF VISUAL ASPECTS IN COMPUTER-GENERATED IMAGES
Title
REAL-TIME CINEMATIC DESIGN OF VISUAL ASPECTS IN COMPUTER-GENERATED IMAGES.
Creator
Obert, Juraj, Pattanaik, Sumanta, University of Central Florida
Abstract / Description
Creation of visually-pleasing images has always been one of the main goals of computer graphics. Two important components are necessary to achieve this goal --- artists who design visual aspects of an image (such as materials or lighting) and sophisticated algorithms that render the image. Traditionally, rendering has been of greater interest to researchers, while the design part has always been deemed as secondary. This has led to many inefficiencies, as artists, in order to create a...
Show moreCreation of visually-pleasing images has always been one of the main goals of computer graphics. Two important components are necessary to achieve this goal --- artists who design visual aspects of an image (such as materials or lighting) and sophisticated algorithms that render the image. Traditionally, rendering has been of greater interest to researchers, while the design part has always been deemed as secondary. This has led to many inefficiencies, as artists, in order to create a stunning image, are often forced to resort to the traditional, creativity-baring, pipelines consisting of repeated rendering and parameter tweaking. Our work shifts the attention away from the rendering problem and focuses on the design. We propose to combine non-physical editing with real-time feedback and provide artists with efficient ways of designing complex visual aspects such as global illumination or all-frequency shadows. We conform to existing pipelines by inserting our editing components into existing stages, hereby making editing of visual aspects an inherent part of the design process. Many of the examples showed in this work have been, until now, extremely hard to achieve. The non-physical aspect of our work enables artists to express themselves in more creative ways, not limited by the physical parameters of current renderers. Real-time feedback allows artists to immediately see the effects of applied modifications and compatibility with existing workflows enables easy integration of our algorithms into production pipelines.
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Date Issued
2010
Identifier
CFE0003250, ucf:48559
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003250
Detecting, Tracking, and Recognizing Activities in Aerial Video
Title
Detecting, Tracking, and Recognizing Activities in Aerial Video.
Creator
Reilly, Vladimir, Shah, Mubarak, Georgiopoulos, Michael, Stanley, Kenneth, Dogariu, Aristide, University of Central Florida
Abstract / Description
In this dissertation we address the problem of detecting humans and vehicles, tracking their identities in crowded scenes, and finally determining human activities. First, we tackle the problem of detecting moving as well as stationary objects in scenes that contain parallax and shadows. We constrain the search of pedestrians and vehicles by representing them as shadow casting out of plane or (SCOOP) objects.Next, we propose a novel method for tracking a large number of densely moving objects...
Show moreIn this dissertation we address the problem of detecting humans and vehicles, tracking their identities in crowded scenes, and finally determining human activities. First, we tackle the problem of detecting moving as well as stationary objects in scenes that contain parallax and shadows. We constrain the search of pedestrians and vehicles by representing them as shadow casting out of plane or (SCOOP) objects.Next, we propose a novel method for tracking a large number of densely moving objects in aerial video. We divide the scene into grid cells to define a set of local scene constraints which we use as part of the matching cost function to solve the tracking problem which allows us to track fast-moving objects in low frame rate videos.Finally, we propose a method for recognizing human actions from few examples. We use the bag of words action representation, assume that most of the classes have many examples, and construct Support Vector Machine models for each class. We then use Support Vector Machines for classes with many examples to improve the decision function of the Support Vector Machine that was trained using few examples via late fusion of weighted decision values.
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Date Issued
2012
Identifier
CFE0004627, ucf:49935
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004627