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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.
311

Automatic safety and speed enforcement systems. An economic study

Rundqvist, Elena January 2010 (has links)
There is a debate in Sweden if the Automatic Safety and speed enforcement systems (SSS) in Sweden are profitable or not. Cost benefit analysis (CBA) is an excellent tool for determining the economy of traffic safety measures. The parameters of the CBA in this work include: tire wear, fuel consumption, environmental pollution, saved lives and injuries, reduced material damage, time for disputing tickets, time in traffic lines due to accidents, longer time due to lower speed and collected fines and maintained cost for the SSS. The sensitivity analysis shows that the SSS system appears to be profitable and the greatest uncertainty arises from the calculation of saved lives. Each SSS will on average generate a profit of approximately 250,000 SEK annually.
312

Marketing Strategies of Passenger Service in High Speed Rail Transport ¡V A case of Taiwan High Speed Rail Corporation

Lee, I-Chen 23 July 2007 (has links)
Safe, high speed, on time, high transport volume, minimum land use, low energy and low pollution are unique features of high-speed rail transport. In countries reaching a threshold level of economic development, traditional railway system will no longer satisfy the need of the mass in cross-township transport. As the cost of energy and demand for environmental protection escalates, high-speed rails have gradually surfaced as a competitive mode of transport in cross-township traveling. Furthermore, it is able to bring regional developments. However, high-speed rail transport is a new industry in Taiwan. There has been no hands-on experience in the passenger service. How then, through the development of marketing strategy and implementation, so as to promote the service quality and customer satisfaction, has been a primary operations objective of high-speed railways. This motivated the need to study the service marketing strategy in high-speed rail transport. The Taiwan High Speed Rail Corporation (THSRC) is the subject of this study. The 7P marketing mix of the service industry was the theoretical foundation. Historical data on the service and marketing strategies of high-speed railways in countries such as Japan, France and Germany were collected. Questions for conducting in-depth interviews with experts in high-speed railway were devised from the study of these historical data. In addition, a survey questionnaire was developed from the data collected via interviews. Passengers taking the Taiwan High Speed Rail were surveyed for statistical analysis. Finally, an appropriate service and marketing strategy was developed. The results show, the Taiwan High Speed Rail needs to first build a brand image of safety and credibility. It needs to schedule and allocate headways in line with its target passenger group and develop a comprehensive product strategy for its target customers. Having done that, it needs to propose competitive price strategies and promotion programs on corporate customers and travel agencies. Making use of the comprehensive mobile telephony coverage and internet network, and more convenient channels should be further developed. Furthermore, the THSRC needs to solve the problem of passenger transfers in station areas gradually. This is necessary to promote the overall service quality, satisfy divergent needs of the target market, and build up a recognized brand in high-speed railway transport. Finally, the recommendations made to THSRC were compared with service and marketing strategies in other countries. It is hoped that the results would be able to provide THSRC and any other countries planning to develop high-speed railway, some practical reference in planning their marketing strategies.
313

Kinematic and Dynamic Analysis of High speed bearing system

Chou, Lin-En 02 July 2001 (has links)
The aim of this thesis is to analyze the kinematic and dynamic characteristics of a high-speed bearing system. The examined kinematic characteristics will include the maximal speed, fatigue life and stiffness of a bearing system. The stability and transmission force of a bearing system as well as the vibration of its shaft were the studied dynamic characteristics. These analyses were based on the kinemitics of bearing systems, rotor dynamics and elastohydrodynamic lubrication theory. According to these analyses, the interaction and consequence among these characteristics and the parameters of a bearing system will be explained. After these analyses, preliminary and simple design trends about a high-speed bearing system are going to be proposed.
314

Design of Distributed-Flow-Type Multi-Speed Hubs for Bicycles

Wen, Tzu-chuang 01 September 2008 (has links)
The planetary gear train are applied in multi-speed drive hubs for bicycles. Since a multi-speed drive hub has the advantages of the small volume and stable gear shifting, it is used widely in folding bicycles and electric bicycles. The distributed-flow-type multi-speed hubs could provide more gears, the related design theory is not well development. Thus, the purpose of this research is to develop a systematical methodology for the design of the distributed-flow-type multi-speed hub for bicycles. First, an existing patent is analyzed to identify the basic characteristics and the requirements of the multi-speed hubs. Based on the basic characteristics and the requirements, a systematical procedure is proposed to synthesize the feasible concepts of the planetary gear trains. Second, another procedure is proposed to determine the feasible clutching sequence tables. Third, the difference in value of the angular velocity is assigned to calculate the gear ratio and to determine the numbers of the teeth of all gears. Finally, the shifting-gear system in the multi-speed drive hubs is designed and arranged. The evaluation of the multi-speed drive hubs is proceeded to select the better alternatives. The result of this work obtains twenty-senven types of the distributed-flow multi-speed hubs for bicycles, three of them could reach sixteen speeds.
315

Stochastic tomography and Gaussian beam depth migration

Hu, Chaoshun, 1976- 25 September 2012 (has links)
Ocean-bottom seismometers (OBS) allow wider angle recording and therefore, they have the potential to significantly enhance imaging of deep subsurface structures. Currently, conventional OBS data analysis still uses first arrival traveltime tomography and prestack Kirchhoff depth migration method. However, using first arrival traveltimes to build a velocity model has its limitations. In the Taiwan region, subduction and collision cause very complex subsurface structures and generate extensive basalt-like anomalies. Since the velocity beneath basalt-like anomalies is lower than that of high velocity anomalies, no first-arrival refractions for the target areas occur. Thus, conventional traveltime tomography is not accurate and amplitude constrained traveltime tomography can be dangerous. Here, a new first-arrival stochastic tomography method for automatic background velocity estimation is proposed. Our method uses the local beam semblance of each common-shot or common-receiver gathers instead of first-arrival picking. Both the ray parameter and traveltime information are utilized. The use of Very Fast Simulated Annealing (VFSA) method also allows for easier implementation of the uncertainty analysis. Synthetic and real data benchmark tests demonstrate that this new method is robust, efficient, and accurate. In addition, migrated images of low-fold data or data with limited observation geometry like OBS are often corrupted by migration aliasing. Incorporation of prestack instantaneous-slowness information into the imaging condition can significantly reduce migration artifacts and noise and improve the image quality in areas of poor illumination. Here I combine slowness information with Gaussian beam depth migration and implement a new slowness driven Gaussian beam prestack depth migration. The prestack instantaneous slowness information, denoted by ray parameter gathers p(x,t), is extracted from the original OBS or shot gathers using local slant stacking and subsequent localsemblance analysis. In migration, we propagate both the seismic energy and the principal instantaneous slowness information backward. At a specific image location, the beam summation is localized in the resolution-dependent Fresnel zone where the instantaneousslowness-information-related weights are used to control the beams. The effectiveness of the new method is illustrated using two synthetic data examples: a simple model and a more realistic complicated sub-basalt model. / text
316

Multi-speed electric hub drive wheel design

Woodard, Timothy Paul 19 November 2013 (has links)
Advances in electro-mechanical actuation have encouraged revolutions in automobile design which promise to increase fuel efficiency, reduce costs, improve safety and performance, and allow a wider range of architectural choices for the vehicle designer and manufacturer. This is facilitated by the concept of an intelligent corner (IC). The IC consists of traction, steering, camber, and suspension actuators working together to control the forces generated at the wheel/surface interface, allowing complete control of vehicle motion with completely active, as opposed to passive, systems. The most critical actuator to the longitudinal performance of an IC vehicle is the traction system, envisioned in this case as a hub mounted electro-mechanical actuator connected directly to the wheel. This traction actuator consists of a number of primary and supplementary components, including a prime mover, gear train, clutch, brake, bearings, seals, shafts, housing, etc. The consideration of these components in the design of an in-hub electric drive actuator is the subject of this report. Currently, gear trains are used in automobiles to match the operating speed of an internal combustion engine (ICE) to the speed of the vehicle on the road. The same need is anticipated for the hub drive wheel, although with fewer reduction ratio choices due to the responsiveness of the electric motor. Specifying a gear train design includes selecting a gear train architecture, and designing the gears to handle the expected loads. A review of gear design and gear train architectures is presented. A number of electric machines are used in industrial, and now more commonly, vehicle applications; of these, the switched reluctance motor (SRM) represents an excellent candidate for a vehicle prime mover due to its ruggedness, broad torque speed curve, low cost, and simplicity. Integrating the motor and gear train into an electro-mechanical actuator with multiple speeds requires consideration of other ancillary components. Brief design guides are presented for clutches, brakes, bearings, seals, and the structure for the in-hub wheel drive. Given the analytical descriptions of the drive wheel components, methods for managing the numerous design parameters are developed and expanded. Actuator specifications are chosen based upon meeting various vehicle performance requirements such as maximum speed, gradeability, acceleration, and drawbar pull. A proposed parametric drive wheel design is presented to meet the requirements of a generic heavy vehicle. The design demonstrates the feasibility of actuator technology that can be used to increase the performance, maintainability, and refreshability of hybrid electric vehicles while allowing open architecture paradigms to lower costs and spur new levels of manufacturing and innovation. / text
317

Using existing highway right-of-way for high-speed passenger trains : a comprehensive evaluation

Larsen, Katherine Anne, 1976- 21 December 2010 (has links)
The implementation of high-speed passenger trains (HST) within existing highway right-of-way (ROW) offers a solution for regions with a demand for the capacity and service offered by HST but lacking the support for sharing freight rail ROW or acquiring new ROW corridors. The states of Florida, Colorado, California and Nevada propose to use highway ROW for their HST projects to increase the capacity of the corridor, prevent or minimize impacts and prevent disruption of freight rail operations. Despite the constraints of using existing highway ROW, such as speed-limiting degrees of curvature and safety concerns, solutions and mitigation measures exist. The purpose of this thesis is to present the HST projects in the United States proposing use of highway ROW, the potential benefits and engineering issues to consider and the feasibility of using the existing I-35 ROW in Texas for HST. / text
318

Processing Speed as a Predictor of Poor Reading

Urso, Annmarie January 2008 (has links)
This study had three main purposes. First, the relationship between Processing Speed (Gs) and poor word recognition skills was examined. Second, various formats of processing speed tests that measure different types of processing speed (i.e. naming facility, perceptual speed, semantic speed, attention and concentration) were administered to determine what aspects of Gs were more strongly correlated with word reading performance. Pearson correlations and coefficients of determination were used to evaluate the strength of the relationships and the shared variance. Third, the study sample was evaluated to determine what percentage of the poor readers participating in the study had slow processing speed.Forty-four students in grades 1-3, ages six- to ten-years old were administered the Woodcock-Johnson III Achievement reading tests of Letter-Word Identification, Reading Fluency, and Word Attack. The subjects were additionally administered the Woodcock-Johnson III Cognitive Abilities tests of Verbal Comprehension, Visual-Auditory Learning, Sound Blending, Visual Matching, Numbers Reversed, Decision Speed, Rapid Picture Naming, Pair Cancellation, and Cross Out.The results of the study indicated processing speed, as measured by the Gs Cluster score, was strongly correlated with word reading, r = .749, r2=.56. The Gs tests of Visual Matching, (r = .663, r2 = .44) and Decision Speed (r = .811, r2 = .66) were most strongly correlated with poor word reading skill. The Basic Reading Skills Cluster and the Test of Letter-Word Identification were both moderately correlated at various strengths with different formats of Gs tests. Tests of Visual Matching, Rapid Picture Naming, Pair Cancellation and Cross Out all had a moderate, significant correlation.Lastly, 47% of the poor readers (SS<85 on any of the measures of>reading) also had low Gs scores (SS<85).The results from the study demonstrate the need for further exploration of the impact of poor Gs on the development of reading skills, as well as determination of the most effective interventions for poor readers with slow processing speed.
319

On Physical Relations in Driving: Judgements, Cognition and Perception

Eriksson, Gabriella January 2014 (has links)
Drivers need to make judgements of physical relationships related to driving speed, such as mean speed, risks, travel time and fuel consumption, in order to make optimal choices of vehicle speed. This is also the case for the general public, politicians and other stakeholders who are engaged in traffic issues. This thesis investigates how drivers’ judgements of travel time (Study I and II), fuel consumption (Study III) and mean speed (Study IV) relate to actual physical measures. A cognitive time-saving bias has been found in judgements of travel time. The time saving bias implies that people overestimate the time saved when increasing speed from a high speed and underestimate the time saved when increasing speed from a low speed. Previous studies have mainly investigated the bias from a cognitive perspective in questionnaires. In Study I the bias was shown to be present when participants were engaged in a driving simulator task where participants primarily rely on perceptual cues. Study II showed that intuitive time saving judgements can be debiased by presenting drivers with an alternative speedometer that indicate the inverted speed in minutes per kilometre. In Study III, judgements of fuel consumption at increasing and decreasing speeds were examined, and the results showed systematic deviations from correct measures. In particular, professional truck drivers underestimated the fuel saving effect of a decrease in speed. Study IV showed that subjective mean speed judgements differed from objective mean speeds and could predict route choice better than objective mean speeds. The results indicate that biases in these judgements are robust and that they predict behaviour. The thesis concludes that judgements of mean speeds, time savings and fuel consumption systematically deviate from physical measures. The results have implications for predicting travel behaviour and the design of driver feedback systems. / Förare bör göra bedömningar som relaterar till hastighet, såsom bedömningar av medelhastighet, risk, restid och bränsleåtgång. Dessa bedömningar är nödvändiga för att föraren ska kunna välja en optimal hastighet, men också för att allmänheten, politiker och andra intressenter som är involverade i trafikfrågor ska kunna fatta välgrundade beslut. Denna avhandling består av fyra delstudier där förares bedömningar av restid (Studie I och II), bränsleåtgång (Studie III) och medelhastighet (Studie IV) studeras i relation till faktiska fysikaliska mått. Tidigare enkätstudier har påvisat ett kognitivt bias i tidsvinstbedömningar vid höga och låga hastigheter som påverkar mänskligt beteende. Studie I visade att detta bias också förekommer i en primärt perceptuell motorisk uppgift där förarna i studien kör i en körsimulator. Studie II visade att dessa intuitiva tidsbedömningar kan förbättras genom att köra med en alternativ hastighetsmätare i bilen som indikerar den inverterade hastigheten i minuter per kilometer istället för hastigheten i kilometer per timme. I Studie III undersöktes bedömningar av bränsleåtgång vid hastighetsökningar och hastighetssänkningar, och resultaten visar att bedömningarna systematiskt avviker från faktisk bränsleåtgång. Ett intressant resultat var att lastbilsförare i allmänhet underskattade bränslebesparingen som kan göras till följd av en hastighetssänkning. Studie IV visade att subjektiva bedömningar av medelhastighet som avviker från objektiva medelhastigheter kan predicera vägval, vilket tyder på att systematiska fel i dessa bedömningar är robusta och kan predicera vägval. Sammanfattningsvis visar avhandlingen hur bedömningar av medelhastighet, tidsvinst och bränsleåtgång systematiskt avviker från fysikaliska mått. Resultaten har betydelse för modellering av resebeteende och design av förarstödssystem. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted.</p>
320

A study of the effects of high speed rotary instruments on bone repair submitted in partial fulfillment ... oral surgery ... /

Youngblood, Philip J. January 1960 (has links)
Thesis (M.S.)--University of Michigan, 1960.

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