Quantification and description of braking during mountain biking using a novel brake power meter : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Sport & Exercise at Massey University, Palmerston North, New Zealand

Olympic format cross country mountain biking is both physically and technically demanding. The demands of this cycling genre are in contrast to road cycling because of the demanding off-road terrain. With its many obstacles and different surfaces, riders must make their way up and over steep hills a number of times throughout a lap. It’s very easy to be able to measure the performance of the riders on ascending sections of the track thanks to on-the-bike personal power meter that measure the propulsive work rates in the pedals. However, there is currently no commercially available method to assess the way the rider handles the bike on descending sections. This thesis first highlighted the differences in physiological demand of descending on off-road versus on-road (Chapter 4). An interesting finding in Chapter 4 also showed that riders might be able to save energy by adopting a coasting strategy down hills. This caused the researchers to question the bicycle handling attributes that might allow this, which led to the development and validation of a device designed to measure how the rider uses the brakes while riding/racing (Chapter 5). From there, we completed an investigation akin to the early mountain biking descriptive studies (Chapter 6), but instead of focusing on data related to respiratory and metabolic load, the brake power meter was employed. The finding that braking patterns were related to mountain biking performance was not surprising, but being the first team to quantify this was very exciting. Since most of the braking was occurring on the descents in that study, we examined the differences in braking between training groups on an isolated turn (Chapter 7). The finding that inexperienced riders use their brakes differently—and that this results in reduced performance—left no doubt to the importance of braking. From there, we revisited the method used to calculate rear brake power, since current methods led to inaccurate measurement during skidding (Chapter 8). This thesis culminated with the exploration of an algorithm that could quickly and easily describe mountain bike descending performance with one single metric (Chapter 9); the hope is that the normalized brake work algorithm should increase the utility of the brake power meter for training purposes and post-competition performance analysis. Overall, this thesis highlights the need, importance and utility of a bicycle brake power meter to assess mountain bike performance

Session A4- Lower Yellowstone River fish passage and entrainment prevention

The Lower Yellowstone Irrigation Project near Glendive, MT, has supplied irrigation water for approximately 54,000 acres of fertile land for over 100 years. The diversion dam presents a passage barrier to the endangered Pallid sturgeon (and other native species) while the unscreened intake allows fish to become entrained in the canal system. An ongoing joint effort between the U.S. Army Corps of Engineers and the U.S. Department of the Interior, Bureau of Reclamation aims to address both the passage and entrainment issues. Entrainment prevention is being addressed through the use of screened intakes on a new headworks structure that is currently under construction. The hydrologic variability of this relatively free-flowing large river and frequent severe ice floes bring unique challenges to the design of fish screens. Numerous fish passage options have been evaluated including bypass channels and a rock ramp. In addition to one- and two-dimensional numerical modeling, 1:20 scale physical models of the rock ramp have been employed to evaluate fish passage criteria. Bypass channel options have been evaluated using one-dimensional numerical modeling. The focus of this presentation is the comparison of results from numerical and physical modeling for multiple alternatives based on depth and velocity criteria

Search for level sets of functions using computer experiments

In engineering and other fields, it is common to use a computer simulation to model a real world process. The inputs to a function f represent factors that influence the outcome. The output represents a quantity of interest. Often there will be a specified level L, and the objective is to find the inputs for which output is above L. L may be a tolerance level, and the inputs for which response is larger than L form a tolerance region. We might estimate the tolerance region by evaluating f on a grid, but even a coarse grid may have thousands of points in four or five dimensions. If the function f is costly to evaluate, we need to be able to estimate the tolerance region with as few evaluations as possible. We approach this problem with a sequential search. Use data at any stage to fit a spatial process that approximates the function. Fit a Gaussian spatial process, as described in Currin, Mitchell, Morris, and Ylvisaker [1991]. The spatial process gives an estimate of the L-contour. We can also use the process to estimate how much information would be gained if f is evaluated at point p. Choose points where it is estimated that f takes value L, but where uncertainty is high. Evaluate f at the chosen points. This will augment the set of data points and the vector of data values. Repeat the procedure with this augmented data. Calculate convergence criteria after each iteration, and stop when criteria reach predetermined goals.;The search process is applied to several functions defined in low dimensional space. Finally, it is applied to an actual simulation function

Warrant, Proper Function, and the Great Pumpkin Objection

Because it eschews classical foundationalism and coherence theory, one must wonder about the reliability of Plantinga’s radical account of knowledge of God’s existence. How does his appeal to proper basicality and epistemic warrant fair against Keith Lehrer’s objections? The answer: not very well. The author gives an analysis of Plantinga’s proper functionality concept, his grounds for warranted belief, and his anticipated response to what he calls the Great Pumpkin Objection. Next, the author presents Lehrer’s two counterexamples, Mr. Truetemp and Ms. Prejudice, and supports Lehrer’s claims that they show that proper functionality is neither a sufficient nor necessary condition for knowledge. Plantinga cannot save himself by drawing a dubious distinction between cognitive process and cognitive faculty, can he? No. Plantinga goes awry somewhere, and perhaps he should think some more about the Great Pumpkin

Kinetic Family and Human Figure Drawings of Child and Adolescent Sexual Offenders

Problem. Juvenile sexual offenders constitute a significant percentage of the total offender population. This study sought to determine whether the KFD and the HFD can be useful in identifying male juvenile sexual offenders by identifying specific characteristics in their drawings that differentiate them from the general population. Method. KFDs, HFDs, and demographic information were collected from 401 male general subjects and 49 male juvenile sexual offenders ages 8 to 17. Forty-three KFD and 30 HFD dependent variables involving emotional and behavioral indicators and sexual symbols were analyzed by Chi-Square Analysis and Discriminant Analysis. Significance was set at .05. Results. There were significant differences between the KFDs and HFDs of juvenile sexual offenders as compared to general subjects. Offenders more often: (1) omitted facial features on the father; (2) omitted the body, arms, hands, and feet on the mother and father figures,- (3) omitted the father and mother figures from their drawings,- (4) drew a long neck on the mother figure,- (5) drew a mother figure that showed lack of nurture,- (6) drew distance between self and the mother and father figures; (7) drew slanting figures; (8) drew KFDs in which the evaluator would not like to live in the family,- (9) drew dangerous objects and activities; and (10) drew barriers between the mother and father figures. Offenders, when drawing a human figure, more often drew: (1) short arms, (2) teeth, (3) large hands, (4) large feet, (5) arms without hands or fingers, (6) dangerous objects. They less often drew with (l) transparencies and (2) dangerous activities. Conclusions. The KFDs of juvenile sexual offenders were significantly different from the general population in 23 of the 43 dependent variables. The HFDs of the offender group were significantly different in 9 variables. These analyses suggest that child and adolescent sexual offenders may be identified by their KFDs and HFDs

Temperature Characterization of the Ultracapacitor Serial Resistance using a Constant Voltage Source

This thesis examines the temperature effects on an ultracapacitor’s equivalent series resistance using a constant voltage source. Previous research has focused on developing models using constant current source. However, as the ultracapacitor technology develops, allowing for the expansion of these devices into new power applications, it is important to understand how ultracapacitors will perform in various temperatures and charging and discharging methods. By predicting the ultracapacitor behavior, systems can be optimized for efficiency and minimize internal circuit losses. For this thesis, Matlab was used to plot the experimental data and to provide best fit curves with their respective coefficients to allow for resistance measurements for one RC time constant to be performed. The research presented in this thesis shows the ultracapacitor’s series resistance was more dependent on change in current than temperature variations. The resistance was did show a minor dependence on temperature, however it was insignificant compared to the change in current levels. The analysis of the resistance values allowed for the development of a resistance equation that accounted for the variations in current and temperature. These resistive equations were compared to the calculated resistance measurements. Sufficient agreement was shown between the developed resistance equations and the calculated resistance values

A simple Monte Carlo model for crowd dynamics

In this paper we introduce a simple Monte Carlo method for simulating the dynamics of a crowd. Within our model a collection of hard-disk agents is subjected to a series of two-stage steps, implying (i) the displacement of one specific agent followed by (ii) a rearrangement of the rest of the group through a Monte Carlo dynamics. The rules for the combined steps are determined by the specific setting of the granular flow, so that our scheme should be easily adapted to describe crowd dynamics issues of many sorts, from stampedes in panic scenarios to organized flow around obstacles or through bottlenecks. We validate our scheme by computing the serving times statistics of a group of agents crowding to be served around a desk. In the case of a size homogeneous crowd, we recover intuitive results prompted by physical sense. However, as a further illustration of our theoretical framework, we show that heterogeneous systems display a less obvious behavior, as smaller agents feature shorter serving times. Finally, we analyze our results in the light of known properties of non-equilibrium hard-disk fluids and discuss general implications of our model.Comment: to be published in Physical Review