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A framework for predicting urban freeway incident delays in real timeMastbrook, Scott 01 November 2008 (has links)
Modern traffic management centers often incorporate incident management support systems. One of the major components of these systems is an incident response module. Decisions on incident response are generally made on a prediction of how much impact an incident will have on a freeway in the sense of delays to drivers.
The goal of this research was to build the framework for an algorithm that can more accurately predict delays due to incidents in real-time given a sufficient amount of data. In this research, many existing delay estimation methods were examined. These include heuristic models, queuing theory, shock-wave theory, time-series methods, and simulation. Most of these methods possessed drawbacks that preclude them from being used in a delay prediction algorithm.
The type of model that was found to give the most flexibility while still being fast enough for on-line applications is a macroscopic freeway simulation model. A dynamic extended model for urban freeways was proposed and tested that proved to model urban freeway traffic phenomena very well. This dynamic model was taken as the basis for a new on-line delay forecasting system.
This research provides an architecture for incorporating a macroscopic simulation with procedures that can be effectively used to provide forecasts of traffic conditions for an urban freeway corridor in real time. The input procedures combine information about freeway characteristics, incidents, and traffic flow conditions into a data package that can be efficiently run through the simulation program. Additional research performed includes a unique survey on the phenomenon of dynamic lane clearance. This phenomenon has a significant impact on delay prediction and was implemented into the architecture. The output from the simulation in terms of traffic flow and speed forecasts is flexible enough be used in many traffic management applications.
When used with a real traffic data set, the simulation has shown to realistically predict future traffic conditions when given the proper input data. An open architecture was used in building the framework, leaving space for additional models that can improve accuracy. Additional research into these areas will further improve the algorithm, increasing both the stability and the accuracy of the forecasts. / Master of Science
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Use of a textile wastewater sludge as a supplemental solid fuelMowery, David Kaiser 01 November 2008 (has links)
The dried sludge by-product generated by the wastewater treatment system at a textile dyeing and finishing facility in southwestern Virginia is currently disposed of in a conventional landfill. This method represents not only a substantial annual cost, but also a potentially serious environmental risk. An investigation was conducted at this facility with the goal of finding an alternative use or market for this by-product of textile manufacturing. After an extensive literature search and initial analyses, the feasibility of using the by-product as a supplemental fuel in the facility's coal boilers was investigated.
Proximate analyses showed that the by-product, with a relatively high heating value and low sulfur content, was fairly well suited for use a supplemental fuel. A brief test-burn of the by-product in one boiler resulted in no observable change in boiler operation or efficiency. Following a conversation with representatives of the Virginia Department of Environmental Quality, a list was formed of the potential air pollutants which are of particular concern when considering combustion processes. Subsequent chemical analyses and mass balances showed that burning the proposed fuel mixture would release acceptably small amounts of a majority of these pollutants. The only pollutants which represent a potential problem are two heavy metals -- chromium and nickel. Additional laboratory testing helped to locate major sources of these elements within the plant. The concentrations of these metals in the final by-product are expected to be reduced to some extent by future source-reduction efforts.
It is recommended that the information contained in this report be used to complete an application for an air permit which would allow the facility to use the by-product as a supplemental fuel in the plant's coal boilers. If this permit application is approved, significant cost savings will be realized not only from the reduction in landfilling costs, but also from a reduction in coal usage. It is further recommended that these cost savings be used to investigate further waste reduction and process optimization measures. / Master of Science
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Fuzzy non-radial measures of relative technical efficiency using DEAParlikar, Virendra R. 18 November 2008 (has links)
Charnes, Cooper and Rhodes [7] developed data envelopment analysis (DEA) to measure the technical efficiency of organizational units. In DEA, these units are referred to as decision making units (DMUs). Deterministic input and output data are assumed when using conventional DEA models. Based on Carlsson and Korhonen's [6] fuzzy parametric programming approach, Girod [15] developed fuzzy radial DEA models to deal with imprecise input and output data. The merits of Girod's approach were that it can be used for scenarios where the decision maker can place upper and lower bounds on the input and output data and, it introduces fuzziness directly in the input and output sets. However, radial models alone are not sufficient to judge an DMU efficient because of excess in usage of inputs and slacks in the production of outputs. Under these circumstances, non- radial DEA models are useful alternative estimates of technical efficiency performance. In this research, fuzzy non-radial models are developed by applying Girod's [15] framework to three non-radial models; the Fare-Lovell model, the Zieschang model and the asymmetric Fare model. A fuzzy two stage radial DEA model is also used to compute fuzzy technical efficiency scores. Comparison of fuzzy radial and non-radial models is carried out. The fuzzy DEA models developed in this research are used to measure technical efficiency of a packaging line in a real world manufacturing system. The specific process studied involves inserting commercial preprints in the fold of newspapers. / Master of Science
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Patterns of natural regeneration in pine and hardwood forests of the Upper Coastal Plain, VirginiaRantis, Polly-Anne 07 November 2008 (has links)
Natural regeneration is the primary means of replacing mature forests of parks and preserves in the absence of forest management. There is growing concern from landowners about how these forests will regenerate. The objective of this study was to examine the pattern of natural regeneration in some unmanaged, mature forests in the Virginia Upper Coastal Plain. Twelve pairs of gap and non-gap areas in each of three cover types: 1) pine, 2) pine-hardwood, and 3) hardwood forests were studied. All levels of forest vegetation were inventoried and species importance values were calculated. Regeneration was categorized by shade tolerance classes for analysis. Soil and light conditions were the measured environmental variables.
Conditions in gap and non-gap areas within each cover type were compared using the paired-t test. There were few clear distinctions in sapling and seedling densities, or sapling heights between gap and non-gap areas in these forest cover types. Light conditions were significantly higher in the gap areas than the non-gap areas; but soil properties were often quite similar. Principal component and best subsets regression analysis were used to determine the relationships between environmental variables associated with gap and non-gap areas and the regeneration present. The principal component analysis showed no meaningful results for the gap and non-gap areas across the environmental data matrix. Few significant relationships were found relating environmental variables and shade tolerance seedling densities using best subsets regression. Conclusive evidence as to which variables were most influential remains unclear. Light and litter depth were most often the significant factors among the forest cover types. / Master of Science
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A systems approach to creating a corporate internal information distribution systemMcRae, Michael R. 01 October 2008 (has links)
The corporate internal information distribution system is designed using the systems engineering model. This system enhances the internal distribution of documents within Lockheed Martin. This distribution system is much timelier and more cost effective than the current means of distribution. Although unable to totally replace the current distribution systems, this system does save Lockheed Martin a considerable amount of money in distribution costs as a complementary system.
The definition of need sets the stage for the design of this system. Advanced system planning provides operational requirements and a conceptual design. Function analysis helps to identify system components and facilitates requirements allocation. The detail design specifies the individual components, which make up the total system, and sets forth an implementation plan as well as a plan for test and evaluation of the integrated system. / Master of Science
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Una casa a LudianoVaught, Margaret Allgair 09 September 2008 (has links)
Master of Architecture
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Usage of computer technology in fabric materials purchasing by large-size apparel manufacturing firmsPriyadarshi, Sarita 02 October 2008 (has links)
The purpose of this study was twofold: (a) to examine the fabric materials purchasing process of apparel manufacturing firms and (b) to determine the relationship between selected organizational factors of apparel manufacturing firms, firms’ usage of computer technology in the fabric materials purchasing process, and firms’ purchasing performance. The type of purchasing situation (i.e, new buy, modified rebuy, straight rebuy) among apparel manufacturers, was determined and was hypothesized to be related to usage of computer technology in fabric materials purchasing process. The selected organizational factors: product characteristics, centralized purchasing, and vertical coordination were hypothesized to be related to usage of computer technology in fabric materials purchasing process. Usage of computer technology was hypothesized to affect firms’ purchasing performance. The conceptual framework for this study was based on the Robinson, Faris and Wind (1967) buygrid framework; Rogers adoption theory (1983); and the Noordewier, John, and Nevin (1990) empirical work. A factor approach was used to examine a cross-section of firms to determine significant characteristics influencing computer technology usage.
The sample consisted of 118 apparel manufacturers. The “Top 100 Sewn Products Companies ‘95” published in the Apparel Industry Magazine, and Dun’s Business Rankings 1995 constituted the source for the sample. The questionnaires were pilot tested with purchasing managers of two large-size apparel manufacturing firms, and also with a group of secretaries at Virginia Tech. Regression, Analysis of Variance, and Correlation were used to test the statistical significance of hypothesized relationships.
The relationship between type of purchasing situation and usage of computer technology was significant. Both straight rebuy and new buy situations were related to usage of computer technology. Demand uncertainty, as a measure of product characteristic, was significantly related to usage of computer technology. The relationship between usage of computer technology and purchasing performance was significant for possession cost and invoice cost as measures of purchasing performance. / Master of Science
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Computer aided analyses of symmetrically loaded thin cylindrical shell using transfer matrix methodShah, Samir Harshadrai 02 October 2008 (has links)
Thin shells as a structural form have made important contribution to the development of several branches of engineering, e.g., chemical, power, structural engineering, etc. The aim of this research is to analyze symmetrically loaded thin cylindrical shell structures using transfer matrix method. A shell is a body bounded by a double curved surface, the thickness of the shell generally being smaller than its radius. A shell is classified thin if the ratio of the thickness to radius is less than twenty.
The analyses of the shell is done using the transfer matrix method. The theory of transfer matrix method is discussed and the analogy between shell and beam on elastic foundation is proved. This analogy between shell and beam is used as a foundation to analyze the shell. Several different loading conditions, e.g., uniform and variable pressure load, ring load etc. are considered. The displacement, shear, angle, moment and various stresses like maximum normal stress, hoop stress, longitudinal stress etc. are found. Shell structures with ring stiffeners are also studied. Several test examples are analyzed and the results are compared to published data. / Master of Science
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Application of molecular markers to characterize potato plants derived from anther culture and protoplast fusionRavichandran, Vidya 07 November 2008 (has links)
Cultivated potato is an autotetraploid (2n=4x=48), i.e., it has four complete sets of chromosomes. Tetraploids can harbor considerable heterozygosity (Jacobs, 1985) since there are potentially four possible alleles per locus. Reducing the ploidy level of potato from the tetraploid to the dihaploid level (2n=2x=24) and then the monoploid (2n=1x-12), or reducing diploid potato spp. to the monoploid level is a way of developing pure homozygous lines by doubling the monoploid genome.
Homozygous breeding lines are important since potato is a highly cross pollinated crop and inbreds are absent. The reduction of the ploidy level can be realised through anther and microspore culture. This method bears a great deal of significance in that it provides a selection against lethal recessive genes. Monoploids carry only a single set of chromosomes and every locus carries only one allele. So the surviving monoploids are devoid of lethal alleles due to the effect of the "monoploid sieve"
Protoplasts are plant cells, the cell walls of which have been digested by a combination of pectinase and cellulase enzymes. If the protoplasts are cultured in a suitable medium, they can resynthesize the cell walls, divide and regenerate complete plantlets. But if a successful fusion of protoplasts from sexually incompatible parents is achieved, the resulting somatic hybrid carries the genome contributed by both parents.
This study aims to apply the molecular tool of RAPD mapping as an efficient agent of plant (potato) genetic characterization of anther-derived monoploids and putative hybrids of a somatic fusion of two monoploids. / Master of Science
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Relationship paradigms and parental divorce: investigating the experiences of adult children from divorced familiesRuble, Stacy Marker 18 September 2008 (has links)
This study addresses the intimate relationships of college students whose parents are divorced. Twenty-one students completed in-depth interviews and written surveys regarding their relationships with their parents, their parents’ marriages, their own intimate relationships, and relationships in general. The purpose of this study was to describe the experiences of these students, and note if any connections can be made between the divorce of their parents and their own relationships, or their feelings about relationships in general. The experiences of the students were quite diverse, but with some common threads. The amount of conflict witnessed, and how the divorce was discussed, seemed to have greater impact on this study's participants than the divorce itself did. A number of students were actually in favor of the divorce due to the high level of conflict between their parents. In their relationships, most study participants avoided conflict. There seemed to be some lack of faith in love and marriage, although most students voiced a desire for both. The divorce seemed to have greater impact on the father-child relationship more so than the mother-child relationship. There needs to be further examination of the intimate relationships of adults with parents who are divorced through a comparison to a control group to determine if the experiences described here are specific to those persons with divorced parents. There also needs to be an examination of a more diverse sample, i.e. greater variance in age, economic status and race. / Master of Science
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