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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Analyzing the impacts of built environment factors on vehicle-bicycle crashes in Dutch cities

Asadi, Mehrnaz, Ulak, M. Baran, Geurs, Karst T., Weijermars, Wendy, Schepers, Paul 03 January 2023 (has links)
Cycling safety policy and research have mostly focused on cycling infrastructure, cyclists' behavior, and safety equipment in the past decades. However, the role ofbuilt environment characteristics (BECs) in the safety of cyclists has not yet been fully examined. For the Netherlands, this is rather surprising given the significant modal share of bicycles in daily trips, the importance attributed to urban spatial planning, and it being one of the most planned countries in the world. Despite the considerable improvements that have ta1cen place in traffic safety over the decades, the ( actual) number of cyclist deaths between 2011 and 2020 increased by on average 2% per year; the cyclists bad a major portion oftraffic death (followed by passenger cars); also, almost onethird of traffic death happened in built-up a.reas (about 25% of fatalities occurred on 50km/h roads in urban areas) in this period. Considering the aim of construction of on average 75,000 new homes per year until 2025, as weil as promoting bicycle use in as a healthy and sustainable mode of transport in the N etherlands, underst.anding the relationships between the BECs and cycling safety is invaluable for improving the safety of cyclists.
32

Transferability and Calibration of the Highway Safety Manual Performance Functions and Development of New Models for Urban four-lane Divided Roads

Al, Kaaf, Khalid 01 January 2014 (has links)
Many developing countries have witnessed fast and rapid growth in the last two decades due to the high development rate of economic activity in these countries. Many transportation projects have been constructed. In the same time both population growth and vehicle ownership rate increased; resulting in increasing levels of road crashes. Road traffic crashes in Gulf Cooperation Council (GCC) is considered a serious problem that has deep effects on GCC's population as well as on the national productivity through the loss of lives, injuries, property damage and the loss of valuable resources. From a recent statistical study of traffic crashes in Oman, it was found that in 2013 there were 7,829 crashes occurred for a total of 1,082,996 registered vehicles. These crashes have resulted in 913, 5591, and 1481 fatal, injury and property damage only crashes, respectively (Directorate General of Traffic, 2014), which is considered high rates of fatalities and injuries compared to other more developed countries. This illustrates the seriousness and dangerousness of the safety situation in GCC countries and Oman particularly. Thus, there is an urgent need to alleviate the Severity of the traffic safety problem in GCC which in turn will set a prime example for other developing countries that face similar problems. Two main data sources from Riyadh, the capital city of Kingdom of Saudi Arabia (KSA) and Muscat, the capital city of Sultanate of Oman have been obtained, processed, and utilized in this study. The Riyadh collision and traffic data for this study were obtained in the form of crash database and GIS maps from two main sources: the Higher Commission for the Development of Riyadh (HCDR) and Riyadh Traffic Department (RTD). The Muscat collision and traffic data were obtained from two main sources: the Muscat Municipality (MM) and Royal Oman Police, Directorate General of Traffic (DGC). Since the ARC GIS is still not used for traffic crash geocoding in Oman, the crash data used in the analysis were extracted manually from the filing system in the DGC. Due to the fact that not all developing countries highway agencies possess sufficient crash data that enable the development of robust models, this problem gives rise to the interest of transferability of many of the models and tools developed in the US and other developed nations. The Highway Safety Manual (HSM) is a prime and comprehensive resource recently developed in the US that would have substantial impact if researchers are able to transfer its models to other similar environment in GCC. It would save time, effort, and money. The first edition of the HSM provides a number of safety performance functions (SPFs), which can be used to predict collisions on a roadway network. This dissertation examined the Transferability of HSM SPFs and developing new local models for Riyadh and Muscat. In this study, first, calibration of the HSM SPFs for Urban Four-lane divided roadway segments (U4D) with angle parking in Riyadh and the development of new SPFs were examined. The study calibrates the HSM SPFs using HSM default Crash Modification Factors (CMFs), then new local CMFs is proposed using cross-sectional method, which treats the estimation of calibration factors using fatal and injury data. In addition, new forms for specific SPFs are further evaluated to identify the best model using the Poisson-Gamma regression technique. To investigate how well the safety performance model fits the data set, several performance measures were examined. The performance measures summarize the differences between the observed and predicted values from related SPFs. Results indicate that the jurisdiction-specific SPFs provided the best fit of the data used in this study, and would be the best SPFs for predicting severe collisions in the City of Riyadh. The study finds that the HSM calibration using Riyadh local CMFs outperforms the calibration method using the HSM default values. The HSM calibration application for Riyadh crash conditions highlights the importance to address variability in reporting thresholds. One of the findings of this research is that, while the medians in this study have oversize widths ranging from 16ft-70ft, median width has insignificant effect on fatal and injury crashes. At the same time the frequent angle parking in Riyadh urban road networks seems to increase the fatal and injury collisions by 52 percent. On the other hand, this dissertation examined the calibration of the HSM SPFs for Urban intersections in Riyadh, Kingdom of Saudi Arabia (KSA) and the development of new set of models using three year of collision data (2004-2006) from the city of Riyadh. Three intersection categories were investigated: 3-leg signalized, 4-leg signalized, and 3-leg unsignalized. In addition, new forms for specific SPFs are further evaluated to identify the best model using the Poisson-Gamma regression technique. Results indicate that the new local developed SPFs provided the best fit of the data used in this study, and would be the best SPFs for predicting severe crashes at urban intersections in the City of Riyadh Moreover, this study examined the calibration of the HSM SPFs for Fatal and Injury (FI), Property Damage Only (PDO) and total crashes for Urban Four-lane divided roadway segments (U4D) in Muscat, Sultanate of Oman and the development of new SPFs. This study first calibrates the HSM SPFs using the HSM methodology, and then new forms for specific SPFs are further evaluated for Muscat's urban roads to identify the best model. Finally, Riyadh fatal and injury model were validated using Muscat FI dataset. Comparisons across the models indicate that HSM calibrated models are superior with a better model fit and would be the best SPFs for predicting collisions in the City of Muscat. The best developed collision model describes the mean crash frequency as a function of natural logarithm of the annual average daily traffic, segment length, and speed limit. The study finds that the differences in road geometric design features and FI collision characteristics between Riyadh and Muscat resulted in an un-transferable Riyadh crash prediction model. Overall, this study lays an important foundation towards the implementation of HSM methods in multiple cities (Riyadh and Muscat), and could help their transportation officials to make informed decisions regarding road safety programs. The implications of the results are extendible to other cities and countries and the region, and perhaps other developing countries as well.
33

Benchmark, Explain, and Model Urban Commuting

Guo, Meng 19 December 2012 (has links)
No description available.
34

Modelo destrutivo com variável terminal em experimentos quimiopreventivos de tumores em animais

Zavaleta, Katherine Elizabeth Coaguila 12 April 2012 (has links)
Made available in DSpace on 2016-06-02T20:06:07Z (GMT). No. of bitstreams: 1 4375.pdf: 903031 bytes, checksum: 03118f406867a5d7be3cbc63571d4a2b (MD5) Previous issue date: 2012-04-12 / Financiadora de Estudos e Projetos / The chemical induction of carcinogens in chemopreventive animal experiments is becoming increasingly frequent in biological research. The purpose of these biological experiments is to evaluate the effect of a particular treatment on the rate of tumors incidence in animals. In this work, the number of promoted tumors per animal will be parametrically modeled following the suggestions given by Kokoska (1987) and Freedman et al. (1993). The study of these chemopreventive experiments will be presented in the context of the destructive model proposed by Rodrigues et al. (2010) with terminal variable that allows or censures the experiment at time of the animal death. Since the data analyzed in this field are subject to excess of zeros (Freedman et al. (1993)), we propose for the number of promoted tumors a negative binomial distribution (NB), a zero-inflated Poisson distribution (ZIP), and a zero-inflated Negative Binomial distribution (ZINB). The selection of these models will be made through the likelihood ratio test and the AIC, BIC criteria. The estimation of its parameters will be obtained by using the method of maximum likelihood, and further simulation studies will also be realized. As a future proposition to finalize this project, it is suggested the Bayesian methodology as an alternative to the method of maximum likelihood via the EM algorithm. / A indução química de substâncias cancerígenas em experimentos quimiopreventivos em animais é cada vez mais frequente em pesquisas biológicas. O objetivo destes experimentos biológicos é avaliar o efeito de um determinado tratamento na taxa de incidência de tumores em animais. Neste trabalho o número de tumores promovidos por animal será modelado parametricamente seguindo as sugestões dadas por Kokoska (1987) e por Freedman et al. (1993). O estudo desses experimentos quimiopreventivos será apresentado no contexto do modelo destrutivo proposto por Rodrigues et al. (2010) com variável terminal que condiciona ou censura o experimento no instante de morte do animal. Os dados analisados possuem uma grande quantidade de zeros, portanto será proposto para o número de tumores promovidos as seguintes distribuições: binomial negativa, a distribuição de Poisson com zeros inflacionados e a distribuição binomial negativa com zeros inflacionados. A seleção destes modelos será feita através do teste da razão de verossimilhança e os critérios AIC, BIC. As estimativas dos respectivos parâmetros serão obtidas utilizando o método de máxima verossimilhança e serão feitos estudos de simulação. Para continuar este projeto, a proposta futura é utilizar a metodologia Bayesiana como alternativa ao método de máxima verossimilhança via algoritmo EM.
35

Accounting for employee share options : a critical analysis

Sacho, Zwi Yosef 30 November 2003 (has links)
The main goal of this dissertation was to obtain an understanding as to the true economic nature of employee share options and the problems surrounding the accounting thereof. The main conclusion of this study is that employee share options should be expensed in the income statement as and when the employee's services are performed. The reason is that employee share options are valuable financial instruments which the employer has used to compensate the employee for his services. It was also concluded that exercise date accounting and classification of outstanding employee share options as liabilities on the balance sheet is the most appropriate accounting treatment. Such accounting treatment trues up the accounting of employee share options with that of cash-settled share appreciation rights, which are economically equivalent transactions. The measurement of employee share options should be based on their fair value using an option-pricing model adapted for the specific features of employee share options. / Accounting / Thesis (M. Com. (Accounting Science))
36

Accounting for employee share options : a critical analysis

Sacho, Zwi Yosef 30 November 2003 (has links)
The main goal of this dissertation was to obtain an understanding as to the true economic nature of employee share options and the problems surrounding the accounting thereof. The main conclusion of this study is that employee share options should be expensed in the income statement as and when the employee's services are performed. The reason is that employee share options are valuable financial instruments which the employer has used to compensate the employee for his services. It was also concluded that exercise date accounting and classification of outstanding employee share options as liabilities on the balance sheet is the most appropriate accounting treatment. Such accounting treatment trues up the accounting of employee share options with that of cash-settled share appreciation rights, which are economically equivalent transactions. The measurement of employee share options should be based on their fair value using an option-pricing model adapted for the specific features of employee share options. / Accounting / Thesis (M. Com. (Accounting Science))
37

Oceňování opcí a variance gama proces / Option Pricing and Variance Gamma Process

Moravec, Radek January 2010 (has links)
The submitted work deals with option pricing. Mathematical approach is immediately followed by an economic interpretation. The main problem is to model the underlying uncertainities driving the stock price. Using two well-known valuation models, binomial model and Black-Scholes model, we explain basic principles, especially risk neutral pricing. Due to the empirical biases new models have been developped, based on pure jump process. Variance gamma process and its special symmetric case are presented.
38

Estimating the Ratio of Two Poisson Rates

Price, Robert M., Bonett, Douglas G. 01 September 2000 (has links)
Classical and Bayesian methods for interval estimation of the ratio of two independent Poisson rates are examined and compared in terms of their exact coverage properties. Two methods to determine sampling effort requirements are derived.
39

Decisão de investimento entre pequenas centrais hidrelétricas e usinas eólicas: aplicação da teoria das opções reais

Giorgetto, Tiago Martinez 03 May 2012 (has links)
Submitted by Tiago Martinez Giorgetto (tigiorgetto@uol.com.br) on 2012-05-28T13:35:54Z No. of bitstreams: 1 TMG_Dissertacao_Mestrado_Maio2012_Final.pdf: 972089 bytes, checksum: 2f6039567098db514bfb12b4ddf0896f (MD5) / Approved for entry into archive by Gisele Isaura Hannickel (gisele.hannickel@fgv.br) on 2012-05-28T15:30:44Z (GMT) No. of bitstreams: 1 TMG_Dissertacao_Mestrado_Maio2012_Final.pdf: 972089 bytes, checksum: 2f6039567098db514bfb12b4ddf0896f (MD5) / Made available in DSpace on 2012-05-28T16:44:23Z (GMT). No. of bitstreams: 1 TMG_Dissertacao_Mestrado_Maio2012_Final.pdf: 972089 bytes, checksum: 2f6039567098db514bfb12b4ddf0896f (MD5) Previous issue date: 2012-05-03 / A Teoria das opções reais tem se mostrado um instrumental relevante na fundamentação das decisões de investimento de diversos agentes na economia, especialmente no que tange a projetos de infraestrutura, pesquisa e desenvolvimento. Dado que o setor energético brasileiro possui um arcabouço institucional que possibilita que diversos agentes privados atuem no setor, a avaliação de empreendimentos de geração de energia ganha destaque, fazendo com que a aplicação desse campo de pesquisa torne-se promissor. Assim sendo, o objetivo desse estudo é avaliar a tomada de decisão em investimentos no setor elétrico brasileiro tendo como base a aplicação da Teoria das opções reais. Para esse estudo foram selecionados, como objeto de análise, as usinas eólicas e as pequenas centrais hidrelétricas. Por meio da Teoria das opções reais conclui-se que a opção de adiar a construção de um desses empreendimentos pode gerar valor para o empreendedor. Além disso, verifica-se que as pequenas centrais hidrelétricas 'dominam' a maioria dos cenários de investimento estudados quando os preços de energia estão em alta, mas caso haja perspectiva de queda de preços no mercado de energia, porém, a decisão torna-se favorável às usinas eólicas. Por fim, é possível verificar que a análise conjunta de empreendimentos de geração de energia através, por exemplo, da abordagem quadrinomial, pode trazer ganhos na avaliação de projetos de investimento no setor elétrico. / Real Options Theory has been an important instrument for investment decisions for several agents in economy, especially for infrastructure projects, research and development. Since Brazilian energy sector has an institutional framework that enables several private agents to act in this sector, the valuation of energy generation projects is highlighted. As consequence, the application of Real Options Theory becomes promising. Therefore, the objective of this study is to evaluate the decision making on investments in the Brazilian electricity sector based on the application of Real Options Theory. For this study were selected for analysis the Wind Farms and the Small Hydro Power Plants. Through Real Options Theory we concluded that the option to defer the construction of these projects can generate value for the entrepreneur. Furthermore, it appears that the Small Hydro Power Plant "dominates" the majority of investment scenarios studied when energy prices are higher but, if there is perspective for prices reduction in the energy market, however, the decision becomes favorable for Wind Farms. Finally, it is possible to verify that the “joint analysis” for projects in energy generation through, for example, quadrinomial approach can bring gains for investors in energy sector

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