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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.
781

Context aware pre-crash system for vehicular ad hoc networks using dynamic Bayesian model

Aswad, Musaab Z. January 2014 (has links)
Tragically, traffic accidents involving drivers, motorcyclists and pedestrians result in thousands of fatalities worldwide each year. For this reason, making improvements to road safety and saving people's lives is an international priority. In recent years, this aim has been supported by Intelligent Transport Systems, offering safety systems and providing an intelligent driving environment. The development of wireless communications and mobile ad hoc networks has led to improvements in intelligent transportation systems heightening these systems' safety. Vehicular ad hoc Networks comprise an important technology; included within intelligent transportation systems, they use dedicated short-range communications to assist vehicles to communicate with one another, or with those roadside units in range. This form of communication can reduce road accidents and provide a safer driving environment. A major challenge has been to design an ideal system to filter relevant contextual information from the surrounding environment, taking into consideration the contributory factors necessary to predict the likelihood of a crash with different levels of severity. Designing an accurate and effective pre-crash system to avoid front and back crashes or mitigate their severity is the most important goal of intelligent transportation systems, as it can save people's lives. Furthermore, in order to improve crash prediction, context-aware systems can be used to collect and analyse contextual information regarding contributory factors. The crash likelihood in this study is considered to operate within an uncertain context, and is defined according to the dynamic interaction between the driver, the vehicle and the environment, meaning it is affected by contributory factors and develops over time. As a crash likelihood is considered to be an uncertain context and develops over time, any usable technology must overcome this uncertainty in order to accurately predict crashes. This thesis presents a context-aware pre-crash collision prediction system, which captures information from the surrounding environment, the driver and other vehicles on the road. It utilises a Dynamic Bayesian Network as a reasoning model to predict crash likelihood and severity level, whether any crash will be fatal, serious, or slight. This is achieved by combining the above mentioned information and performing probabilistic reasoning over time. The thesis introduces novel context aware on-board unit architecture for crash prediction. The architecture is divided into three phases: the physical, the thinking and the application phase; these which represent the three main subsystems of a context-aware system: sensing, reasoning and acting. In the thinking phase, a novel Dynamic Bayesian Network framework is introduced to predict crash likelihood. The framework is able to perform probabilistic reasoning to predict uncertainty, in order to accurately predict a crash. It divides crash severity levels according to the UK department for transport, into fatal, serious and slight. GeNIe version 2.0 software was used to implement and verify the Dynamic Bayesian Network model. This model has been verified using both syntactical and real data provided by the UK department for transport in order to demonstrate the prediction accuracy of the proposed model and to demonstrate the importance of including a large amount of contextual information in the prediction process. The evaluation of the proposed system delivered high-fidelity results, when predicting crashes and their severity. This was judged by inputting different sensor readings and performing several experiments. The findings of this study has helped to predict the probability of a crash at different severity levels, accounting for factors that may be involved in causing a crash, thereby representing a valuable step towards creating a safer traffic network.
782

The policing of road rage incidents in the Gauteng Province

Mfusi, Boikhutso Florencia 12 1900 (has links)
This study followed a qualitative research approach, and semi-structured interviews regarding the subject matter were conducted with the knowledgeable and experienced respondents in the Gauteng traffic-related departments. A literature review was also conducted to provide a comprehensive understanding of the research problem in both local and international context. The research stresses the fact that motorists are continuing to lose their lives on Gauteng province, as a result of violent traffic disputes, therefore people suffer financial, physical, psychological as well as social effects as a consequence of such actions. The findings revealed that all the traffic stakeholders are working cooperatively towards implementing the crime prevention strategic plans, but for policing road rage in particular there is no specific strategy in action. In addition, this study reveals that it is impossible for the traffic police to curb road rage incidents because the latter occur as a result of unpredictable human behavior. / Police Practice / M. Tech. (Policing)
783

The Control of Multiple Actuators using Single IEHEC Pump/Motor

Bekele, Teshale, Åman, Rafael, Handroos, Heikki 28 April 2016 (has links) (PDF)
The awareness and concern of our environment together with legislation have set more and more tightening demands for energy efficiency of non-road mobile machinery(NRMM). Integrated electro- hydraulic energy converter (IEHEC) has been developed in Lappeenranta University of Technology (LUT) /1/. The elimination of resistance flow, and the recuperation of energy makes it very efficient alternative. The difficulties of IEHEC machine to step to the market has been the requirement of one IEHEC machine per one actuator. The idea is to switch IEHEC between two actuators of log crane using fast on/off valves. The control system architecture is introduced. The system has been simulated in co-simulation using Simulink/Mevea. The simulated responses of pumpcontrolled system is compared to the responses of the conventional valve-controlled system.
784

A Thermal Analysis of Direct Driven Hydraulics

Minav, Tatiana, Papini, Luca, Pietola, Matti 02 May 2016 (has links) (PDF)
This paper focuses on thermal analysis of a direct driven hydraulic setup (DDH). DDH combines the benefits of electric with hydraulic technology in compact package with high power density, high performance and good controllability. DDH enables for reduction of parasitic losses for better fuel efficiency and lower operating costs. This one-piece housing design delivers system simplicity and lowers both installation and maintenance costs. Advantages of the presented architecture are the reduced hydraulic tubing and the amount of potential leakage points. The prediction of the thermal behavior and its management represents an open challenge for the system as temperature is a determinant parameter in terms of performance, lifespan and safety. Therefore, the electro-hydraulic model of a DDH involving a variable motor speed, fixed-displacement internal gear pump/motors was developed at system level for thermal analysis. In addition, a generic model was proposed for the electric machine, energy losses dependent on velocity, torque and temperature was validated by measurements under various operative conditions. Results of model investigation predict ricing of temperature during lifting cycle, and flattened during lowering in pimp/motor. Conclusions are drawn concerning the DDH thermal behavior.
785

An analysis of implementing open road tolling through the Gauteng Freeway Improvement Project (GFIP)

Malahleha, Thabiso 03 1900 (has links)
Thesis (MDF) -- Stellenbosch University, 2011. / ENGLISH ABSTRACT: The aim of this research report is to analyse the feasibility of Open Road Tolling (ORT) and its development in South Africa through the Gauteng Freeway Improvement Project (GFIP). ORT represents the next generation of Electronic Toll Collection (ETC) and this research report will assess to what extent the GFIP scheme is in line with other comparable tolling schemes; and is the institutional environment amenable to ORT. This will allow one to gauge the feasibility of the scheme and its potential for acceptability and success. The research report outlines the number of risks that come with an ORT scheme and these include amongst others collection risk, enforcement, technology, privacy and public acceptance. The success of the GFIP will largely be determined by how well these risks are mitigated and how the benefits can be marketed to the users. The literature review illustrates that whether road pricing schemes have failed to move forward, have been implemented, are currently under development, or still in the planning stage as a concept there are several consistent lessons and critical success factors one should apply when structuring a scheme. In the discussions with stakeholders, the following conclusions with regards to the feasibility of ORT and its development in South Africa were as follows: - The factors which need to be addressed include political risk, effective marketing of the scheme to the public, obtaining political will and support, building trust between the scheme developer and the user, managing perceptions and acknowledgement of the fact that the scheme will need to prove itself over time. - Inadequate demonstration - Incorporating interoperability yields benefits in terms in terms of network externalities, the ability to use a single transponder for multiple tolling plazas and points, along with the potential for alternative uses for the transponder. - ORT as a viable solution for the GFIP is feasible from a technical point in that it’s the only way in which one can collect tolls from a high volume network and not cause disruptions in the flow of traffic. However, there are a number of persistent residual risks that SANRAL cannot entirely mitigate and some fall under the realm of political risk. - While SANRAL has applied best practice principles in structuring the GFIP with the aim of providing value for money for the user and as far as possible tackling the issue of affordability, there are certain realities, such as the recent global financial crisis, the infrastructure backlog of the country, users paying for roads which were free and challenges with overall service delivery which place a strain on the legitimacy of the GFIP ORT scheme.
786

Public private partnerships (PPPS) for road infrastructure development in Mauritius : the case of small island developing states (SIDS)

Ramlugan, Amaresh Singh 12 1900 (has links)
Thesis (MDF)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Governments have a pivotal role in meeting the ever-increasing demand for socio-economic services in transport, energy, telecommunications, water, education, health and delivery of other social services. However, the major issue in Mauritius is the lapsus in road infrastructure. The road infrastructure agenda in Mauritius needs to be revisited, as such, maintenance has been insufficient to prevent deterioration and there are some other reasons for the damage. Urgent rehabilitation and reconstruction is required to avoid further damage. Factors such as, deficit of funding, absence of coordination between the public and the private sector, changes in political regimes, lack of transparency in the procurement process and lack of adequate legal framework are factors to which the failure of implementing Public Private Partnership (PPP) in Mauritius can be attributed. However, the implementation of PPP might enhance the nature and efficacy of the way in which public money is spent and encourage resilience and competency of the taxation structure. Governments will therefore be apt to consider strategic partnerships in order to promote state-of-the-art technological advancement and enhance managerial skills and capabilities. Reviews discussed by the Government of Mauritius were taken from annual reports and an in-depth study was carried out. Moreover, as secondary analysis differs from systematic reviews and meta-analyses of qualitative studies, which aim instead to compile and assess the evidence relating to a common concern or area of practice, both secondary analysis and meta-analysis have been used. Therefore, this study comprised of a thorough, narrative discussions of research studies which epitomize attempts to make sense of the rapidly expanding research on PPP in Mauritius. From the narrative discussion, it can be highlighted that, controversy arose over the claims for surplus expenses of Rs 709 million on a preliminary agreement of Rs 2.2 billion. Moreover, due to factors such as massive non-alignment between government and private sector, unclear government goals and duties, multifaceted resolution, sectoral policies not well defined, regulatory challenges and limitations, risk management issues, poor reliability of public policies, insufficient local capital markets, poor mechanisms to attract cheaper long term capital, weak lucidity and absence of a competitive landscape, a delay in the implementation of PPP was encountered. However, an emergence in the number of PPPs has been witnessed in developing countries, not only because of their increasingly being viewed as value-for-money but also for the reasons that follow: enhancing the delivery of public sector services at lower costs, integrating protection of the environment by ensuring fulfilment of green requirements and promoting competition. Reviews and extracts show that Mauritius requires financial support to implement PPP projects. However, the availability of international aid has helped the country to gain faith in the implementation of PPP projects thus, helping the Small Island Developing State of Mauritius to look at the future of its development with confidence.
787

Road infrastructure and rural poverty in Ethiopia

Wondemu, Kifle Asfaw January 2010 (has links)
In the face of high population growth and declining natural resource base, tackling rural poverty necessitates an increase in overall factor productivity or a rise in the market rate of return of assets possessed by the poor. Towards achieving these objectives, the role of spatial integration of markets and the efficiency with which these markets operate are considerably important, as these factors shape the structure of incentives and the level of opportunities open to the rural poor. As a result, factors that hinder the spatial integration of markets and their efficient operation will have significant impact on rural poverty. In Ethiopia markets are often segmented mainly due to high transport cost associated with poor road infrastructure. The existing poor quality and low road density are expected to contribute to rural poverty through limiting the size of the market, increasing market risk (price volatility), widening the spatial prices gaps, reducing the market return to land and labour, inflating the profitability of new technologies and reducing the incentive to produce for market. This research endeavours to empirically substantiate if there is a robust link between farm income and the quality of road infrastructure farm households have access to as well as the pathways through which the effects of road on rural income are felt. The empirical result consistently showed that improving rural road access will have significant impact on rural income in general and the income of the poor in particular. The mechanisms by which road boosts rural income and reduce poverty are also found to work through narrowing down spatial price gaps, promoting technology adoption, boosting resource allocation efficiency and raising the market return to land and labour. The result also showed that the rural poor benefits from road induced income growth.
788

Investigating the influence of vehicular traffic on a major trunk road on rural air quality

Obara, Paul Goodluck January 2012 (has links)
Traffic population in the UK has grown by 27% in 2002 and predicted to continue to an estimated 38% in 2016 and up to 60% by 2031. This means vehicular emissions from road transport may account for higher proportion of total emissions of pollutants resulting in air pollution with its attendant consequences. Although poor air quality concerns has often been linked to urban areas, many rural areas apparently have locations where air quality objectives may be threatened especially in the wake of increasing vehicular population. Thus, this elicits the necessity to investigate the relationship between vehicular emissions and air quality. This study investigated the influence of vehicular traffic on a major trunk road on rural air quality through continuous measurements of nitrogen dioxide, sulphur dioxide and hydrocarbon between June 2008 and April 2010 along a major trunk road in a catalogued rural environment in the UK. Collection and analysis of pollutants was by Dräger short-term tubes and Dräger passive diffusion tube techniques. Throughout the sampling period, concentrations of sulphur dioxide were not detected using the short-term tube technique but were detected by the passive diffusion tubes. The study found that variations in mean concentrations of the pollutants were synonymous with traffic frequency and were influenced by meteorological conditions especially wind speed, temperature and relative humidity. Results observed concentration decline trend with increasing distance and showed maximum concentrations during winter, mainly in areas of close proximity to anthropogenic source, and minimum in summer. Values between winter year 1 and winter year 2 monitoring campaigns showed significant difference (P<0.05 and R=0.91) as was in summer year 1 and year 2 (P<0.05 and R=0.94), spring year 1 and year 2 (P<0.05 and R=0.84) and autumn year 1 and year 2 (P<0.05 and R=0.79). When compared with the guidance limits, NO2 Page ii showed exceededance at roadside and 50 m, and at some sample sites, up to 100 m from the road. Conversely, SO2 did not show any exceedance but statistical analyses was mostly significant between concentrations and distance at p≤0.05, suggesting the variability of pollutants, as well as the influence of distance on their temporal and spatial distribution. Results also show that pollutants correlated very well with daily traffic population with strong positive r2 and R-values. Similarly, the study considered the application of hazel leave (Corylus avellana) and ryegrass (Lolium perenne) vegetation samples in monitoring rural air quality. Both samples were collected in different seasons and distances (5m, 50m, and 100m) from the A49 trunk road at four rural sites characterised with diverse traffic densities and anthropogenic activities. The aim was to determine the elemental content and trends within the samples and to investigate the influence of distance from the road, height from ground level, and sampling season on the elemental levels. The levels of Al, As, Ba, Ca, Si, Mg, S, Cd, Cr, Na, Ni, Sb, Se, Sn, Mo, Mn, C, K, P, Cl, Ti, Fe, Zn, and Pb were determined using X-ray fluorescence (XRF), inductively coupled plasma-mass spectrometer (ICP-MS), and Scanning Electron Microscopy-Energy Dispersive X-ray spectrometer (SEM-EDX). Results show that despite the traffic differentials between the sampling sites, the pollution level of heavy metals were generally low in all sampling site and concentrations of Cr, Cu, Ni, Pb, and Ti exhibited inverse relationship with distance, decreasing in levels with increasing distance from the trunk road. Although root uptake from the soil is a potential source of heavy metals, geochemistry research of the study area did not show any evidence that proves any major heavy metals deposit concerns in the soil. It is therefore possible that heavy metal emissions were deposited in a form that was not readily available for root uptake, thereby narrowing the presence of heavy metal pollutants to other potential Page iii sources. However, this study found high level of heavy metals at the roadside measurements in the order of Zn (0.703 ppm) > Ti (0.346 ppm) > Cr (0.111 ppm) > Cu (0.106 ppm) > Pb (0.026 ppm) > Ni (0.025 ppm). They were found in different magnitudes higher than their respective levels at 50 and 100 m from the trunk road and therefore tend to support traffic origin. Findings from this study show that heavy metals exhibited different degree of correlation between individual elements, ranging from very strong positive to weak, as well as negative correlations. Statistical analyses show that the elements predominantly exhibited statistically significant differences between elements and between distances from the road. Overall, findings from this study demonstrate that both vegetation species prove to be successfully useful in determining the pollution status and trends of traffic-related heavy metals.
789

Electronic road pricing in Singapore: lessonsfor Hong Kong

Ng, Wing-suen, Sammuel., 伍永璇. January 1999 (has links)
published_or_final_version / Transport Policy and Planning / Master / Master of Arts
790

Studying the feasibilities of electronic road pricing and bus rapid transit to solve traffic congestion in Guangzhou city proper

蘇力行, So, Lek-hang, Lake. January 2008 (has links)
published_or_final_version / Urban Planning and Environmental Management / Master / Master of Science in Urban Planning

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