This research explores a higher order of fast tracking, called Flash Tracking, in response to increasing calls for faster, more reliable project deliveries. Flash Tracking is defined as a time-driven project, which by necessity requires a heightened degree of concurrency between engineering, procurement, and construction. In contrast to fast tracking, which entails a level of concurrency between engineering, procurement, and construction that has become a staple of the construction industry, Flash Tracking extends the envelope by requiring a series of innovative practices across the project delivery spectrum. The specific research questions pursued include: 1) identifying which innovative improvements in project delivery methodology could be made to compress project durations, while maintaining safety, quality, and risk tolerance, and 2) addressing how project teams can best overcome barriers to delivering shorter project durations. A multi-method research project was undertaken to address these questions, which entailed an extensive review of the literature, structured case study interviews, and multiple group decision-making exercises. The literature review focused on the construction industry, as well as manufacturing, shipbuilding, and software development, to identify practices and techniques potentially relevant to Flash Tracking that could be extended to the construction industry. Group decision-making exercises included a modified Delphi method study, an Analytic Hierarchy Process, and a series of research charrettes or focus groups. These studies produced a prioritized, two-tiered listing of 47 essential Flash Track practices, providing practitioners with both a measure to assess their readiness for undertaking a Flash Track project and strategies for increasing their readiness. A subsequent study--a semantic network analysis--refined and buttressed the research team’s earlier findings. This two-year study, conducted in concert with industry experts, led to a re-engineered engineering, procurement, and construction (EPC) model which embraces relational contract strategies, improved communications, and the early engagement of key stakeholders.

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New railway track is laid to a specified level and alignment. However, with time and trafficking movements occur in the ballast bed and the underlying subgrade, and frequent maintenance is necessary to re-establish the correct geometry. This is currently done by the process of tamping, where extra material is vibrated under the sleeper to raise its level. Unfortunately this is not permanent, and the sleeper eventually reverts to its premaintenance state. Prior to mechanised tamping, track was relevelled by hand shovel packing in which the sleepers were raised and fine aggregate shovelled into the space under the sleeper, giving a permanent lift. A prototype of a mechanised version of this process, called the Stoneblower, has been developed and is currently undergoing field trials. It lifts the sleeper and blows single size stone smaller than the ballast into the void space, creating a two layer granular foundation for each sleeper. In order to get a better understanding of the behaviour of a two layer granular foundation when subjected to repeated loading a laboratory study involving large scale cyclic triaxial testing of single size and two layer ballast has been carried out. This has been complemented by a large scale model study using a 'half sleeper rig' in which ballast beds similar to those produced by stoneblowing have been subjected to repeated loading simulating long term railway trafficking. These tests have been used to carry out a parametric study into stone angularity, stone size and layer geometry to assess their influence on the layered system, with the results being assessed primarily in terms of the resilient modulus and plastic deformation undergone by the material. In the triaxial tests it was found that the layer of smaller material was the major controlling factor for the deformation. However, the layer of larger material tended to act as a restraint, effectively reducing the HID ratio of the specimen. In the model testing, it was found that the smaller material dictated how the load was transmitted to the ballast bed, and this was then responsible for the majority of the settlement.

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Thesis (Ed.M.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

The purpose of this study was to find the best robot configuration for climbing and descending stairs, in addition to traveling on flat surfaces. Candidate robot types were analyzed to find the most suitable one for further study, based on stability, size, and energy consumption. Based on these considerations, the non-variable configuration tracked robot type was selected. The basic robot parameters (minimum track size, comparison of tracks with grousers vs. tracks without grousers, track angle of attack) were determined using static analysis methods and using North American standards for the stair geometry. Dynamic analysis methods were then employed to refine the geometry and ensure the stability of the robot when climbing and descending stairs. The final design was then simulated in Matlab to profile the device's velocity, acceleration, and power consumption during the stair climbing and descending phases. A prototype robot was constructed. The results of this study show that a non-variable tracked robot can be constructed for the purpose of climbing stairs by applying static and dynamic analysis techniques to optimize a design. This study provides the groundwork for this design, which can also serve as a basis for designing robots with other configurations.

The purpose of this study was to find the best robot configuration for climbing and descending stairs, in addition to traveling on flat surfaces. Candidate robot types were analyzed to find the most suitable one for further study, based on stability, size, and energy consumption. Based on these considerations, the non-variable configuration tracked robot type was selected. The basic robot parameters (minimum track size, comparison of tracks with grousers vs. tracks without grousers, track angle of attack) were determined using static analysis methods and using North American standards for the stair geometry. Dynamic analysis methods were then employed to refine the geometry and ensure the stability of the robot when climbing and descending stairs. The final design was then simulated in Matlab to profile the device's velocity, acceleration, and power consumption during the stair climbing and descending phases. A prototype robot was constructed. The results of this study show that a non-variable tracked robot can be constructed for the purpose of climbing stairs by applying static and dynamic analysis techniques to optimize a design. This study provides the groundwork for this design, which can also serve as a basis for designing robots with other configurations.

Abstract Population size and trends of large carnivores are difficult to determine, but are often needed to inform conservation actions. Direct counts maintained over long time periods are extremely difficult to achieve. Indices of population sizes can be used to estimate large carnivore abundances, but are often case-, species- and sitespecific. Here, we test the general applicability of track-based indices to estimate large carnivore abundance. We surveyed 15 306.4km of roads associated with 339 transects across a wide geographical scale, large range of densities and variable substrates for tracks of African large carnivores. A combined model for all carnivore species on sandy soils serves as a robust approach to predict large carnivore densities. Thus, indices based on track counts can provide useful estimates of carnivore abundance. We found consistent relationships between track densities and the actual carnivore densities, having taken account of substrate.

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