No description available.

Since the first discovery of a transiting planet in 2000, transmission spectroscopy has proved essential for characterising the rapidly increasing number of known extrasolar planets. When a planet is in a favourable alignment, it periodically passes (transits) in front of its host star, during which time it blocks a fraction of the stellar light. During a transit, the starlight passes through the planetary atmosphere, causing the signatures of atoms or molecules present in that atmosphere to imprint themselves on the stellar spectrum, allowing direct observation of a planet's atmospheric composition. At the start of this thesis, only two planets (HD 189733b and HD 209458b) had been studied in any detail, mainly from space. The two planets showed surprisingly different qualities for two objects with only a small temperature difference between them, and motivated both wider and more detailed studies of the exoplanet population. Since the start of my PhD, the amount of exoplanet knowledge has grown rapidly, with observations from the ground becoming important, and with studies branching out towards new planets. There are several contributions made by this thesis to the field. Chapter 3 details the detection of the resolved sodium D doublet in the atmosphere of HD 189733b, a planet with a featureless broad-band transmission spectrum dominated by Rayleigh scattering. The results confirmed the presence of sodium absorption as well as resolving the feature for the first time, and placing constraints on relative abundances. Furthermore, in Chapter 4, I outline a method based on earlier work which allows observers to retrieve atmospheric temperature information from resolved spectral features. This method is applied to the observations of HD 189733b, showing that the planet has a hot thermosphere similar to HD 209458b. The models are then also used in later chapters. I then present the first results from a ground-based optical long-slit spectroscopic survey in Chapter 5, and the first results from a space-based optical-near-IR spectroscopic survey in Chapter 6. From the ground, I detect absorption from sodium in the atmosphere of XO-2b, making this the first planet with sodium and potassium detected in its atmosphere. I also find that the Na I D feature lacks broad line wings, suggesting haze or cloud cover. From space, I observed the transmission spectrum of WASP-19b, finding solar abundance water features and a likely lack of predicted TiO features. WASP-19b is the first planet to have confirmed water features at solar-abundance level. In Chapter 7 I conclude and discuss future work, including a project aimed at understanding why WASP-19b lacks TiO features, and projects which move beyond the hot Jupiter class.

Ridership in the New Orleans region is down, and transit agencies are challenged to increase transit performance. Transit professionals expect many benefits from cooperation between transit systems in the region including an increase in efficiency and effectiveness. The question is "do these cooperative initiatives between transit agencies improve transit performance?" To answer this question a survey has been held to collect data regarding regional initiatives implemented by transit agencies. In addition data were collected from the transit agencies websites. The analysis focused on the comparison between agencies that implemented regional initiatives versus agencies that did not implement any regional initiative. From the analysis it appears that although agencies have implemented cooperative initiatives they are not very convinced that it had a significant impact on transit performance. Further, results show that cooperation might have some positive impact on transit performance, but are not as convincing as literature and transit professionals expect

Wong Chi Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 105-106). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Literature Review --- p.3 / Chapter 1.3 --- Thesis Outline --- p.5 / Chapter 2 --- The Timetable Synchronization Problem --- p.7 / Chapter 2.1 --- Underlying Assumptions --- p.7 / Chapter 2.2 --- The Timetable Synchronization Problem (TTSP) --- p.10 / Chapter 2.2.1 --- Time-Horizon Boundary Concerns --- p.10 / Chapter 2.2.2 --- Transfer Waiting-times Declaration --- p.11 / Chapter 2.2.3 --- Set Declarations --- p.13 / Chapter 2.2.4 --- Parameter Declarations --- p.14 / Chapter 2.2.5 --- Variable Declarations --- p.16 / Chapter 2.2.6 --- Model Description --- p.17 / Chapter 2.3 --- Alternative Formulation --- p.22 / Chapter 2.4 --- Summary --- p.24 / Chapter 3 --- Solution Approach --- p.25 / Chapter 3.1 --- Computation Comparison of the Two Formulation --- p.25 / Chapter 3.2 --- CPLEX Parameter Settings --- p.26 / Chapter 3.3 --- Optimization-based Heuristic Method (OHM) --- p.26 / Chapter 3.3.1 --- Why Modify? - Sharper LP-Relaxation --- p.28 / Chapter 3.3.2 --- How to Predict and Release --- p.30 / Chapter 3.4 --- Performance of the OHM --- p.31 / Chapter 3.5 --- Summary --- p.32 / Chapter 4 --- Case Study of the MTR in HK --- p.33 / Chapter 4.1 --- Problem Settings --- p.33 / Chapter 4.1.1 --- Train Routes --- p.33 / Chapter 4.1.2 --- Cross-platform Times --- p.34 / Chapter 4.1.3 --- Testing Horizon --- p.35 / Chapter 4.1.4 --- Number of Trains --- p.35 / Chapter 4.1.5 --- Allowable Adjustments to Operational Parameters --- p.36 / Chapter 4.2 --- Solution Quality --- p.37 / Chapter 4.2.1 --- Average Transfer Waiting-times --- p.37 / Chapter 4.2.2 --- Possible Maximum Transfer Waiting-times --- p.37 / Chapter 4.2.3 --- """Just Miss""" --- p.38 / Chapter 4.3 --- Summary --- p.39 / Chapter 5 --- Solution Quality in Different Settings --- p.40 / Chapter 5.1 --- Optional Operational Constraints I - Improve Regularity --- p.41 / Chapter 5.1.1 --- Regularity of Dwell-times --- p.41 / Chapter 5.1.2 --- Regularity of Headway --- p.43 / Chapter 5.2 --- Cases Analysis I --- p.44 / Chapter 5.2.1 --- Case Analysis 1 - l Steps to Use the System --- p.45 / Chapter 5.2.2 --- Case Analysis 2 - Varying Run-times --- p.47 / Chapter 5.2.3 --- Case Analysis 3 - Non-rush Hour --- p.49 / Chapter 5.2.4 --- Case Analysis 4 - Varying Regularity of Dwell-times . . --- p.52 / Chapter 5.3 --- Cases Analysis II --- p.55 / Chapter 5.3.1 --- Optional Operational Constraints II - Increasing Dwell-times (1) --- p.55 / Chapter 5.3.2 --- Case Analysis 5 - Adding Special Dwell-times Bounds . --- p.56 / Chapter 5.4 --- Case Analysis III --- p.58 / Chapter 5.4.1 --- Optional Operational Constraints III - Increasing Dwell-times (2) --- p.58 / Chapter 5.4.2 --- Case Analysis 6 - Adding Modified Special Dwell-times Bounds --- p.59 / Chapter 5.5 --- Future Work --- p.61 / Chapter 6 --- Timetable-Synchronization System --- p.62 / Chapter 6.1 --- Hierarchy of the Timetable-Synchronization System --- p.64 / Chapter 6.2 --- Use of the Component Software Tools --- p.66 / Chapter 6.2.1 --- ILOG CPLEX 7.5 --- p.66 / Chapter 6.2.2 --- Microsoft Visual Basic. Net 2003 --- p.66 / Chapter 6.2.3 --- Microsoft Office XP - Excel --- p.67 / Chapter 6.2.4 --- Microsoft Office XP - Access --- p.68 / Chapter 6.3 --- Summary --- p.69 / Chapter 7 --- Conclusions --- p.70 / Chapter 7.1 --- Summary and Further Studies --- p.70 / Appendix --- p.72 / Chapter A --- The MTR System in HK --- p.73 / Chapter B --- Abbreviation of Routes --- p.74 / Chapter C --- Abbreviation of Interchange Stations --- p.75 / Chapter D --- Passenger Groups --- p.76 / Chapter E --- Average Transfer Waiting-times (08:00-ج09:00) --- p.78 / Chapter F --- Maximum Transfer Waiting-times (08:00-ج09:00) --- p.79 / Chapter G --- Using the Timetable-Synchronization System --- p.80 / Chapter G.l --- Steps to Use the System --- p.82 / Chapter H --- Timetable-Synchronization System Problem Generator --- p.85 / Chapter H.1 --- "Use of the ""Timetable-Synchronization System Problem Gen- erator""" --- p.85 / Chapter H.2 --- "Hierarchy of the ""Timetable-Synchronization System Problem Generator""" --- p.86 / Chapter H.3 --- "Using the ""Timetable-Synchronization System Problem Gen- erator""" --- p.87 / Chapter I --- Transfer Waiting-time Calculator --- p.94 / Chapter I.1 --- Use of Transfer Waiting-time Calculator --- p.94 / Chapter I.2 --- Using the Transfer Waiting-time Calculator --- p.95 / Chapter J --- Database Structure in Microsoft Access --- p.97 / Chapter J.1 --- Operational Parameters --- p.98 / Chapter J.1.1 --- Use of Operational Parameters --- p.98 / Chapter J.1.2 --- Structure of the Tables --- p.98 / Chapter J.2 --- Current Timetable --- p.102 / Chapter J.2.1 --- Use of Current Timetable --- p.102 / Chapter J.2.2 --- Structure of the Tables --- p.102 / Chapter J.3 --- Patronage --- p.103 / Chapter J.3.1 --- Structure of the Table --- p.104 / Bibliography --- p.106

Thesis (M. A.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Dhaka is the capital city of Bangladesh and the centre of administrative, political, economic and social life for the country. An efficient transit system is needed in this city to provide services in every corner and to the people of all socio economic standing. This city is characterized by both motorized and non-motorized transport services, though there is a huge demand on the bus transit system. Dhaka is also one of the fastest growing global cities, which is contributing to even higher transit demand. There is a need, therefore, to investigate the present transit system with a view to understand the opportunities and potential of the current public transport system given available policy support and resources. This research is an initiative to identify the current efficiency status of transit services and explore the opportunities to increase the efficiency of this system for the people of this mega city. To carry out this research, along with literature and policy review, interviews with stakeholders and a survey of transit operators was undertaken. From the analysis of the operator’s survey and literature review, the current underperforming status of transit services was identified. From the discussion of interviews and policy frameworks, strategies to improve the current status and guidelines for future initiatives are outlined. This includes a separate and powerful institutional authority solely for transit services and taking regulatory measures by this authority to speed up STP implementation. For bus transit only, the recommendations are: consolidating bus industry and exclusive bus lanes to improve current status of bus transit service. Finally by achieving and fulfilling the recommendations of this study, it is hoped that a more efficient transit system in Dhaka city would result.

Travel patterns in Canadian urban areas changed during the twentieth century. No longer is urban travel downtown oriented. In all but the smallest Canadian urban areas, travel has evolved into a polycentric pattern. Despite this Canadian public transit networks remain oriented to the older travel patterns because of shortages in planning capacity. The transit literature on performance monitoring focuses on “system” variables rather than “network” variables like how well transit networks match travel patterns. This research develops a method by which transit planners can monitor the performance of transit networks in their communities. Applying this methodology provides recommendations to planners on how to improve transit network structures to better facilitate polycentric urban travel. Future research should compare the network performance of Canadian transit systems.

There are many cities in North America planning to upgrade or implement public transportation infrastructure with the goals of increasing transit ridership and promoting transit-oriented development. The most commonly considered transit systems in mid-sized cities are bus rapid transit (BRT) and light rail transit (LRT). Planners and engineers in these cities often debate on which of these modes offer the more appropriate technology to meet the cities’ transit requirements. From a transportation engineering perspective, the goal of technology selection should be to choose the mode that has the best set of attributes – investment cost, operating cost, environmental and land use impacts – for the city and / or region. This thesis presents the development of an easy-to-use and accessible model (available via website) that assists in the technology selection process, considering investment costs, operating costs and environmental impacts. The objectives of this model include: finding annual costs for the transit modes being evaluated, finding the most appropriate transit mode for a specific scenario, finding the demand at which both transit modes have the same annual costs, testing the sensitivity that outputs have to inputs, finding annual emissions produced for both modes, and showing results that are visual and easy to understand. The model developed in this thesis is applicable mainly in mid-sized cities, which are interested in implementing new, or to improve existing transit systems into, rapid transit systems, like LRT and BRT, but the methods could be easily extended to apply it to other technologies as well. The model was applied to four cases to determine which mode would be more appropriate in these scenarios. The cases that will be studied include: Region of Waterloo in Ontario; Victoria, British Columbia; Cleveland, Ohio; and Mexico City. The results of the analysis made to these four case studies showed how the model can be used in the technology selection process. For these cases it was found that, for the Region of Waterloo and Victoria, LRT would be the less expensive mode in an annual basis, while, for Cleveland and Mexico City, BRT would be the less expensive mode. The break-even point analysis concluded with three main outcomes: for the Region of Waterloo this point would be 1200 passengers/hour and for Victoria it would be 1500 passengers/hour, which is less than the projected ridership for both cases; and for the other two cases (Cleveland and Mexico City) this point was not found for the stated scenario. The findings in the emissions module were the following: for the Region of Waterloo and Victoria: LRT would be the cleaner mode for all emissions; and for Cleveland: LRT would be the cleaner mode when considering NOx, but BRT would be the cleaner mode for SO2 and CO2. Future research can be conducted in adding more technologies into the comparison made in the model making the model functional for smaller and/or larger cities. Further investigation can also be applied in the emissions module creating a larger database to make this module capable of obtaining results in a global scale.

Travel patterns in Canadian urban areas changed during the twentieth century. No longer is urban travel downtown oriented. In all but the smallest Canadian urban areas, travel has evolved into a polycentric pattern. Despite this Canadian public transit networks remain oriented to the older travel patterns because of shortages in planning capacity. The transit literature on performance monitoring focuses on “system” variables rather than “network” variables like how well transit networks match travel patterns. This research develops a method by which transit planners can monitor the performance of transit networks in their communities. Applying this methodology provides recommendations to planners on how to improve transit network structures to better facilitate polycentric urban travel. Future research should compare the network performance of Canadian transit systems.

Public transit provides an important community service by reducing pollution, traffic congestion, and by providing transportation for those who do not or cannot drive. Yet since the 1950s, real investment levels in transit have declined in many North American cities which has resulted in diminished service levels and ridership. In order for transit agencies to attract more riders, transit service must be competitive with alternative modes of transport, particularly private automobiles. However, since funding is limited, planning staff must ensure that the service changes that are implemented result in the greatest benefits to the system. This thesis presents an iterative approach to evaluating service changes in a transit network that combines the output from sophisticated transportation models, demographic data, and software analysis with local knowledge and expertise. The thesis focuses specifically on three common challenges in transit planning: quantifying costs of transfers between destinations within a system, examining access distances to transit as a measure of transit supportiveness, and estimating ridership changes resulting from small route adjustments. Three GIS-based tools, referred to as the Transfer, Access and Route Planning Tools, were developed to address these challenges and were demonstrated using transit system data from the Region of Waterloo in Southwestern Ontario. The Transfer Tool was used to highlight trips with high transfer costs to determine which changes in the route structure would result in the greatest reduction of the generalized cost of a trip attributed to transfers. Results from the Access Tool and Route Planning Tools demonstrated how changes to the streets along which transit routes operate influence access distances to transit, and further, transit ridership. The Access Tool also demonstrated how the design of the street network and the presence of pedestrian paths may affect access distances. Finally, this thesis concludes by recommending areas of future research.