Research suggests that a multidimensional approach to obesity that addresses physiological, psychological, social, and environmental factors is optimal. Stress and self-esteem, as well as eating and exercise behaviors have been named as important factors in obesity. Curiously, although pets have been shown to reduce stress and are associated with higher self-esteem and cardiovascular health, the relationship between pet ownership and weight status has not been explored. A path analysis of the direct and indirect effects of pet ownership on stress, self-esteem, physical activity, eating behavior, and Body Mass Index failed to reveal a clear path linking pet ownership to weight status.

Manitoba Hydro owns and operates 12 river hydroelectric generating stations ans two major control structures. The structures control the flow of water almost exclusively with gate wheels. It is important for the roller paths to remain true to allow uniform distribution of the hydraulic load on the gates to the gate wheels. Manitoba Hydro is currently replacing the distorted steel roller paths at its MacArthur Generating Station. The purpose of this study was to evaluate the physical properties of high strength proprietary grouts to determine their adequacy for use beneath new roller paths of water control gates which have unusual spacial constraints. Two full size mockups of a portion of an existing guide, with a steel overlay, were utilized in the experimental study. To investigate the stress-strain distribution in the mockup under specific loading condition, strain gauges were installed on both of the web sides of the embedded steel I-beam: one group of gauges was located just below the flange, the others were located along the mid-hight of the beam web. Force gauges were inserted to measure the pressure between the thin grout layer bottom and the top of the embedded I-beam. A special LVDT (linear variable differential transducer) assembly was made to measure the maximum displacement of grout layer. Mockup samples were subjected to static and cyclic loading procedures at two designated loading points. The grout cylindrical creep tests were conducted at the same time. It included tests at room temperature and at the elevated temperature of 50°C. The initial sustained load was 50% of the ultimate compression strength of the grout cylinder (3"x6"). Once the creep development was observed to become constant, the sustained load was raised up to 70% of ultimate strength and held constant until the end of the test. The test results indicate that the strength of the proposed grouting material is adequate to resist the required load, both statically and cyclically. Temperature has no significant effects on this specific loading situation. The proposed grouting method is proven to be simple, economic and efficient, therefore, the technique is suitable for roller path repairing.

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The present study examined 8 -10 month-old and 11 -13 month-old infants’ capabilities to infer constraints imposed by an explicit visual pathway on object movement of object. In a preferential looking paradigm, infants observed a ball rolling down a U– or V–shaped path. In the U-shaped path, infants observed a ball rolling from beginning to the end of the path (possible), and a ball rolling down from the beginning and stopping midway of the path (impossible). In the V-shaped path, infants observed a ball rolling from beginning and stopping midway (possible), and a ball rolling down the beginning to end of the path (impossible). Analyses of looking times showed a marginal effect on path, with longer looking times towards the possible V-shaped path by both age groups. Overall, infants had weak representations for constraints induced by an explicitly presented path on movement of the object.

Det statliga järnvägsnätet som byggdes i Sverige under 1800-talets senare del har haft stor betydelse för landets tillväxt. Banornas sträckning och byggsätt gav upphov till livliga debatter i riksdagen som slutligen resulterade i det stambanenät som än idag ligger till grund för Sveriges transportinfrastruktur. Vilken spårvidd som skulle användas var en viktig fråga i debatterna, och att Sveriges statsbanor skulle ha en och samma spårvidd var långt ifrån självklart. Denna studie undersöker och analyserar varför de norrländska stambanorna slutligen kom att byggas med samma spårvidd som övriga landets stambanor, och därigenom bli en integrerad del av det statliga järnvägsnätet. Ursprungligen var de norrländska banorna tänkta att byggas med smalare spårvidd, något som skulle innebära att detta nätverk skulle ha isolerats från södra Sveriges. Detta beslut ändras emellertid innan byggandet påbörjats. Genom att kvalitativt studera riksdagsprotokollen från debatterna om järnvägen som byggdes mellan Storvik till Torpshammar och vidare till den norska riksgränsen för att ansluta till en norsk bana kommande från Trondheim, undersöks de argument som framfördes i debatten ur dels en sociopolitisk och dels en ekonomisk synvinkel. Som förklaringsmodell används teorin om spårbundenhet, path dependence, ur två aspekter; institutionell spårbundenhet och ekonomisk spårbundenhet. Uppsatsen finner att båda aspekterna av spårbundenhet hade betydelse för beslutet att bygga stambanan av samma spårvidd som det övriga stambanenätet. Vidare befinns även de politiska relationerna med Norge inverka på beslutet att bygga banan med en bred spårvidd. / The construction of public railways in Sweden during the 19th century has played a vital part in the country’s economic growth. The geographical and technological aspects of the construction spurred extensive debates in the Swedish Parliament and the choice of gauge was a key aspect of these debates. This qualitative case study examines the arguments and outcomes of the 19th century railway debate in the Swedish parliament by applying the path dependence theory on the sociopolitical and economical process seen in the argumentation. The social structures, financial aspects and political union between Sweden and Norway all mattered in the decision to build all of the public railway system using using the same gauge which later became standard. The findings show that path dependence is relevant when explaining gauge selection from both an institutional and economical perspective.

Variable Selection has always been a very important problem in statistics. We often meet situations where a huge data set is given and we want to find out the relationship between the response and the corresponding variables. With a huge number of variables, we often end up with a big model even if we delete those that are insignificant. There are two reasons why we are unsatisfied with a final model with too many variables. The first reason is the prediction accuracy. Though the prediction bias might be small under a big model, the variance is usually very high. The second reason is interpretation. With a large number of variables in the model, it's hard to determine a clear relationship and explain the effects of variables we are interested in. A lot of variable selection methods have been proposed. However, one disadvantage of variable selection is that different sizes of model require different tuning parameters in the analysis, which is hard to choose for non-statisticians. Xin and Zhu advocate variable ranking instead of variable selection. Once variables are ranked properly, we can make the selection by adopting a threshold rule. In this thesis, we try to rank the variables using Least Angle Regression (LARS). Some shrinkage methods like Lasso and LARS can shrink the coefficients to zero. The advantage of this kind of methods is that they can give a solution path which describes the order that variables enter the model. This provides an intuitive way to rank variables based on the path. However, Lasso can sometimes be difficult to apply to variable ranking directly. This is because that in a Lasso solution path, variables might enter the model and then get dropped. This dropping issue makes it hard to rank based on the order of entrance. However, LARS, which is a modified version of Lasso, doesn't have this problem. We'll make use of this property and rank variables using LARS solution path.

Crane lift path planning is time-consuming, prone to errors, and requires the practitioners to have exceptional visualization abilities, in particular, as the construction site is congested and dynamically changing. This research presents a methodology based on robotics motion planning to numerically solve the crane path planning problem. The proposed methodology integrates a database in order to automatically conduct 2D path planning for a crane lift operation, and accounts for the rotation of the lifted object during its movements. The proposed methodology has been implemented into a computer module, which provides a user-friendly interface to aid the practitioners to perform a collision-free path planning, and check the feasibility of the path at different stages of the project. Three examples are described in order to demonstrate the effectiveness of the proposed methodology and illustrate the essential features of the developed module. / Construction Engineering and Management

The expected yield to maturity on a defaultable obligation equals the nominal yield less expected default losses. However, in a mark-to-market world, one doesn't have the luxury of reporting one's performance on the basis of yield to maturity. Total return is calculated for an arbitrary holding period, and must reflect any mark-to-market gains or losses as at the close of the period-gains or losses that can be triggered by the bond's upgrade or downgrade. Thus to estimate expected total return, one must estimate not only expected default losses, but also the impact on capital price of expected ratings transitions. This paper begins with the observation that a bond which is blessed by more favourable transition characteristics is likely to produce a higher total return, and poses the question of how that benefit can be quantified. How much is it worth? To answer the question, I start by specifying a formal bond-pricing model reflective of ratings transitions. I survey various statistical methods and past research efforts to identify the ratings-transition matrix which best parametrises the model, and propose a novel test for selecting between competing matrices. Using this approach, I replicate several important studies of ratings transitions. I also use it to examine new published and unpublished data, testing for (and finding) ratings path-dependency, and otherwise exploring the effect of ratings changes on different bond sectors. I then turn to the question of whether it is possible to estimate bond-specific transition probabilities, and propose a way to do so. I combine these efforts into the specifications for a pricing model capable of answering the question: How much is it worth?

The conventional information used to guide automobile drivers in selecting their driving routes is the shortest-distance path (SDP). As several researchers have pointed out, driver route selection is a multiple criteria decision process. This research proposes a multiobjective path optimisation (MOPO) decision model to make a more precise simulation of the decision-making behaviour of driver route selection. Seven single-objective path optimisation (SOPO) decision models are taken into account to establish the MOPO decision model. They relate to travel time, travel cost, cumulative distance, roadway capacity, roadway grade, passed intersections and number of turns. To solve the MOPO problem, a two-stage technique which incorporates shortest path (SP) algorithms and techniques for solving the multiobjective programming problem and a path genetic algorithm (PGA) are proposed. In addition, algorithms such as Dijkstra, A* and GA are reviewed and algorithms that are applicable for solving the MOPO problems are suggested. Furthermore, new algorithms for solving least-node path (LNP) problem, corresponding to the objective of passed intersections, as well as minimum-turn path (MTP) problem, corresponding to the objective of number of turns, are developed. To conduct the empirical study, a software tool - the multiobjective path optimisation analysis tool (MOPOAT) - was implemented. It contains tools for constructing a road network and its corresponding network topology, the environment of coding techniques for solving the MOPO problems and tools for the manipulation, statistics, analysis and display of experimental results. The purpose of implementing the MOPOAT software is to provide more efficient, convenient and user-friendly tools for solving MOPO and SOPO problems so that an empirical study of real road networks can be carried out more easily. To demonstrate the advantages of the proposed model in supporting more diverse information to drivers to assist in route selection, several experiments were conducted utilising three real road networks with different roadway types and numbers of nodes and links. Techniques and algorithms such as the two-stage approach, Dijkstra and the PGA for solving the MOPO problem, and the Dijkstra, LNP and MTP algorithms for solving the SOPO problems were applied. Finally, to deal with improvements in computational efficiency for identifying SPs in a large road network and for population initialisation of the PGA, the critical-section (CS) approach and the seed-path expansion (SPE) approach are proposed. To compare the run time between the conventional SP and CS algorithms as well as the PGA and the SPE algorithms, tools were implemented with commercial GIS, and experimental tests were conducted using road networks with a large amount of nodes and links and different roadway types. Through these theoretical and empirical studies, several useful contributions and conclusions were obtained. Some of the most significant findings are: 1. The experimental results demonstrate the advantages of integration with commercial GIS packages in supporting both spatial and attribute data displays. It can be safely said that, assisted by the MOPOAT software, it is easy for automobile drivers to obtain the optimal paths of the SDP, LNP, MTP and MOPO problems in seconds, despite these problems being highly complex and difficult to resolve manually. 2. According to the experimental results, the proposed LNP, MTP and MOPO decision models give automobile drivers richer information for choosing their driving routes in a more diverse way. 3. It is shown by the experimental results that the SDP and LNP mostly locate different paths in both radial-circumferential and grid-type road networks, and that the total passed intersections by the SDP are greater than passed by the LNP. Moreover, it is revealed that ambiguous turns might occur in both radial-circumferential and grid-type road networks. 4. It is found that the number of nodes of the SDP is in general greater than the number of nodes of the LNP and MTP irrespective of the type of road network. 5. A sensitivity analysis for weights shows that as the weighting value of the SDP objective incrementally increases by 0.1 units, the corresponding SDP??s objective value varies either low or high. The same results also occur for the LNP and MTP objectives. This verifies the fact that the weighting coefficients do not reflect proportionally the relative importance of the objectives. Moreover, the MTP objective has the higher sensitivity in comparison with the other two objectives. 6. Despite utilising Dijkstra or PGA algorithms for solving the MOPO problem, the LNP and MTP algorithms have to be employed to solve the non-commeasurable problem, whereby the standardisation objective value can be obtained. In addition, without any assisting information the PGA might fail to reach the best-compromise solution. 7. It is found that the total run time for solving the MOPO problem by applying the Dijkstra algorithm is much faster than by the PGA. However, if the run time excludes the time needed for population initialisation, the PGA is much faster than the Dijkstra algorithm. 8. Based on calculated bottlenecks, the proposed CS approach partitions a SP into many critical sections in advance, with the result that a long SP can be obtained by combining all SPs of all CSs. The experimental results show that the run time of the CS algorithm is much faster than Dijkstra??s algorithm. Moreover, the test result for the P-pointer indicates that if the total number of nodes of a SP grows the computational efficiency of the CS algorithm becomes significantly better than the Dijkstra algorithm, and that the CS approach has the best performance. 9. The experimental result for the E-pointer reveals that the computational efficiency of the CS algorithm will decrease gradually as the number of selected CSs increases. Therefore, the total percentage of selected CSs suggested by the experimental result is no more than 30 percent. 10. According to the experimental results, the performance order among SDP, LNP and MTP algorithms from fast to slow is SDP, MTP and LNP, and the LNP algorithm requires much more time than the other two algorithms. 11. As the total nodes of a path increase, most of the run time for SDP and LNP also increases. However, there are still some paths that violate the above rule. This result verifies that the run time needed for solving SDP and LNP is not only affected by the node numbers but also depends on the network topology. 12. Run time for solving the MOPO problem by applying the PGA is faster than applying the Dijkstra algorithm, if the run time of the former algorithm does not take into account the population initialisation time. Nevertheless, if the run time of the former algorithm does take into account the population initialisation time, the latter algorithm is much faster than the former algorithm. 13. In comparing the run time for population initialisation, the run time of the evolution process by applying the PGA is quite small, and the bottleneck of the run time for solving MOPO problem by applying the PGA is the population initialisation. 14. The population initialisation time is reduced significantly by applying the SPE algorithm, and increases at a very slow rate as the number of nodes of a path increases. As the total nodes of a path grow ever larger, the computing time is reduced more noticeably.

This thesis presents an indoor obstacle avoidance system for car-like mobile robot. The system consists of stereo vision, map building, and path planning. Stereo vision is performed on stereo images to create a geometric map of the environment. A fast sparse stereo approach is employed. For different areas of the image there are different optimal values of disparity range. A multi-pass method to combine results at different disparity range is proposed. To reduce computational complexity the matching is limited to areas that are likely to generate useful data. The stereo vision system outputs a more complete disparity map. Abstract Map building involves converting the disparity map into map coordinates using triangulation and generating a list of obstacles. Occupancy grids are built to aid a hierarchical collision detection. The fast collision detection method is used by the path planner. Abstract A steering set path planner calculates a path that can be directly used by a car-like mobile robot. An adaptive approach using occupancy grid information is proposed to improve efficiency. Using a non-fixed steering set the path planner spends less computation time in areas away from obstacles. The path planner populates a discrete tree to generate a smooth path. Two tree population methods were trialled to execute the path planner. The methods are implemented and experimented on a real car-like mobile robot.