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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.
601

The Effects of Worker Age on Lifting: Psychophysical Estimates of Acceptable Loads and their Link to Biomechanics

Chen, Jade Ashley January 2012 (has links)
Canada’s workforce, as well as many other countries, is continuing to age as the baby boomer generation (those born between 1946 and 1964) ages and are remaining in the workforce longer. The number of older workers is estimated to double within the next 10 years (Perry 2010). With increased age, there are a number of factors that could influence worker performance and risk of injury. For example, aging is associated with decreased strength and cardiovascular fitness. However, it is unknown whether a worker’s estimates of how much they can safely lift (based on an approach called psychophysics, which is often used in the design of manual materials handling tasks) is lower for older compared to younger workers. The primary goal of this thesis was to test the hypothesis that psychophysical estimates of maximum acceptable forces would be lower for older workers than younger workers during selected lifting tasks. The secondary goal was to measure a host of variables to provide insights into what factors (e.g. kinematic, strength, cardiovascular) might be influencing potential age-related differences. The experimental testing protocol used a psychophysical approach to identify the maximum acceptable mass of an object during several lifting tasks. Participants comprised a total of 24 female workers (12 older (50+ years old) and 12 younger (20-30 years old)). The primary outcome of interest was the maximum acceptable weight of lift (MAWL) for an 8 hour work day that would allow each participant to ‘work as hard as they can without straining themselves, or becoming unusually tired, weakened, overheated, or out of breath’ (Snook and Ciriello 1991). The participants completed four lifting tasks: floor-to-knuckle height (1 lift/9s and 1 lift/2 min) and knuckle-to-shoulder height (1 lift/2 min and 1 lift/8 hr) by adding or removing lead shot to a lifting box. Tasks were 30 minute in duration; participants could adjust the load mass at any time during the trial. The dependent variables collected were the MAWL (the load mass at the end of the trial), maximum sagittal plane joint angles of the shoulder, hip and knee, overall and body part specific ratings of perceived exertion, and heart rate. Older workers selected MAWL values that were significantly lower (by approximately 24%) than their younger counterparts. These age-related differences were more prevalent for tasks which were constrained by strength (i.e. low frequency) compared to those with large cardiovascular requirements (i.e. high frequency). The only significant difference in the sagittal plane joint flexion angle was for the right hip during the 1 lift/2 min from floor-to-knuckle height lifting task, characterized by 34.4 degree decrease hip angle (more flexed) for the older workers. There were also no significant age-related differences in overall ratings of perceived exertion. The only body part-specific rating of perceived exertion with a significant age-related difference was for the knees, with the younger workers reporting the tasks more taxing on this joint than the older workers. Although there were no age-related differences in absolute heart rate values, the older workers were at a significantly higher percentage of their maximum heart rate. The results of this work suggest there is value in continued research probing whether current ergonomic and work design guidelines need to be updated to accommodate the aging working population. According to the results presented in this study, the current approaches often employed during the design of manual materials handling tasks (i.e. incorporating the loads that 75% of females could perform based on the Snook and Ciriello tables (1991) may not be sufficiently protective for older female workers in the workplace.
602

Tal, text, handling. En undersökning av viljor och hur dessa uttrycks i handling i Tjechovs Tre systrar

Johansson, Eva January 2013 (has links)
In this essay I have examined text, speech and action in Chekhov's Three sisters, as well as how the characters express their wills in action and in speech. I have used different methods such as action analysis, the five W questions and BSI (background, situation and intention). These methods are similar to those actors use to uncover situatedness of characters and to find motivated and intentional patterns behind their actions. I have used these techniques to identify the plot, explore what happened before the plot begins and to read the text in terms of action. The aim was also to find the counter points where wills expressed in action are contradicted by wills expressed in speech. Using these methods I found that the characters in Three sisters manage their lives dreaming about the future or recalling the past, except the character Natasha. Her goal is obvious, she runs her will with clear intentions and she uses functional means to achieve her goal. The main conclusion is that the characters’ wills expressed in speech, are contradicted by will expressed in action. This creates a discrepancy. The characters are controlled by their unspoken desires which drive them further away from their expressed goals. It seems to be paradoxical, but it makes perfect sense since it drives the plot forward, deepens the image of the characters and the relationships between them. It also becomes clear when actions are interpreted from wills and motivations, stated or unstated, and I argue that action is not only the doing but also the intention to do; this makes sense when events in a dramatic text are analyzed as relational and conditional.
603

Designing a Message Handling Assistant Using the BDI Theory and Speech Act Theory

Song, Insu Unknown Date (has links)
This thesis introduces a new approach to designing a Message Handling Assistant (MA). It presents a model of an MA and an intention extraction function for text messages, such as emails and Newsgroups articles. Based on a speech act theory and the belief-desire-intention (BDI) theory of rational agency, we define a generic MA. By interpreting intuitive descriptions of the desired behaviours of an MA using the BDI theory and speech act theory, we conjecture that intentions of messages alone provide enough information needed to capture user models and to reason how messages should be processed. To identify intentions of messages written in natural language, we develop a model of an intention extraction function that maps messages to intentions. This function is modelled in two steps. First, each sentence in a message is converted into a tuple (performative, proposition) using a dialogue act classifier. Second, the sender's intentions are formulated from the tuples using constraints for felicitous human communication. As an investigation of the use of machine learning technologies for designing the intention extraction function, four dialog act classifiers are implemented and evaluated on Newsgroups articles. The thesis also proposes a semantic communication framework, which integrates the agent and Internet technologies for automatic message composing and ontology exchange services.
604

A biomechanical analysis of patient handling techniques and equipment in a remote setting.

Muriti, Andrew John, Safety Science, Faculty of Science, UNSW January 2005 (has links)
Remote area staff performing manual patient handling tasks in the absence of patient lifting hoists available in most health care settings are at an elevated risk of musculoskeletal injuries. The objective of this project was to identify the patient handling methods that have the lowest risk of injury. The patient handling task of lifting a patient from floor to a chair or wheelchair is a common task performed in a remote health care setting. The task was performed utilising three methods, these being: (1) heads/tails lift, (2) use of two Blue MEDesign?? slings and (3) use of a drawsheet. The task of the heads/tails lift was broken down into two distinctly separate subtasks: lifting from the (1) head and (2) tail ends of the patient load. These techniques were selected based on criteria including current practice, durability, portability, accessibility, ease of storage and cost to supply. Postural data were obtained using a Vicon 370 three - dimensional motion measurement and analysis system in the Biomechanics & Gait laboratory at the University of New South Wales. Forty reflective markers were placed on the subject to obtain the following joint angles: ankle, knee, hip, torso, shoulder, elbow, and wrist. The raw data were converted into the respective joint angles (Y, X, Z) for further analysis. The postural data was analysed using the University of Michigan???s Three-Dimensional Static Strength Prediction Program (3D SSPP) and the relative risk of injury was based on the following three values: (1) a threshold value of 3,400 N for compression force, (2) a threshold value of 500 N for shear force, and (3) population strength capability data. The effects on changes to the anthropometric data was estimated and analysed using the in-built anthropometric data contained within the 3D SSPP program for 6 separate lifter scenarios, these being male and female 5th, 50th and 95th percentiles. Changes to the patient load were estimated and analysed using the same computer software. Estimated compressive and shear forces were found to be lower with the drawsheet and tail component of the heads/tails lift in comparison to the use of the Blue MEDesign?? straps and head component of the heads/tails lift. The results obtained for the strength capability aspect of each of the lifts indicated a higher percentage of the population capable of both the drawsheet and tail end of the heads/tails lift. The relative risk of back injury for the lifters is distributed more evenly with the drawsheet lift as opposed to the heads/tails (tail) lift where risk is disproportionate with the heavier end being lifted. The use of lifter anthropometrics does not appear to be a realistic variable to base assumptions on which group of the population are capable of safely performing this task in a remote setting. This study advocates the use of the drawsheet lift in a remote setting based on the author???s experience and the biomechanical results obtained in this study. The drawsheet lift is both more accessible and provides a more acceptable risk when more than two patient handlers are involved, in comparison to the other lifts utilised lifting patients from floor to a chair.
605

Development of optimization methods to solve computationally expensive problems

Isaacs, Amitay, Engineering & Information Technology, Australian Defence Force Academy, UNSW January 2009 (has links)
Evolutionary algorithms (EAs) are population based heuristic optimization methods used to solve single and multi-objective optimization problems. They can simultaneously search multiple regions to find global optimum solutions. As EAs do not require gradient information for the search, they can be applied to optimization problems involving functions of real, integer, or discrete variables. One of the drawbacks of EAs is that they require evaluations of numerous candidate solutions for convergence. Most real life engineering design optimization problems involve highly nonlinear objective and constraint functions arising out of computationally expensive simulations. For such problems, the computation cost of optimization using EAs can become quite prohibitive. This has stimulated the research into improving the efficiency of EAs reported herein. In this thesis, two major improvements are suggested for EAs. The first improvement is the use of spatial surrogate models to replace the expensive simulations for the evaluation of candidate solutions, and other is a novel constraint handling technique. These modifications to EAs are tested on a number of numerical benchmarks and engineering examples using a fixed number of evaluations and the results are compared with basic EA. addition, the spatial surrogates are used in the truss design application. A generic framework for using spatial surrogate modeling, is proposed. Multiple types of surrogate models are used for better approximation performance and a prediction accuracy based validation is used to ensure that the approximations do not misguide the evolutionary search. Two EAs are proposed using spatial surrogate models for evaluation and evolution. For numerical benchmarks, the spatial surrogate assisted EAs obtain significantly better (even orders of magnitude better) results than EA and on an average 5-20% improvements in the objective value are observed for engineering examples. Most EAs use constraint handling schemes that prefer feasible solutions over infeasible solutions. In the proposed infeasibility driven evolutionary algorithm (IDEA), a few infeasible solutions are maintained in the population to augment the evolutionary search through the infeasible regions along with the feasible regions to accelerate convergence. The studies on single and multi-objective test problems demonstrate the faster convergence of IDEA over EA. In addition, the infeasible solutions in the population can be used for trade-off studies. Finally, discrete structures optimization (DSO) algorithm is proposed for sizing and topology optimization of trusses. In DSO, topology optimization and sizing optimization are separated to speed up the search for the optimum design. The optimum topology is identified using strain energy based material removal procedure. The topology optimization process correctly identifies the optimum topology for 2-D and 3-D trusses using less than 200 function evaluations. The sizing optimization is performed later to find the optimum cross-sectional areas of structural elements. In surrogate assisted DSO (SDSO), spatial surrogates are used to accelerate the sizing optimization. The truss designs obtained using SDSO are very close (within 7% of the weight) to the best reported in the literature using only a fraction of the function evaluations (less than 7%).
606

Performance analysis and design of batch ordering policies in supply chains

Karaman, Abdullah Siddik. January 2007 (has links)
Thesis (Ph. D.)--Rutgers University, 2007. / Graduate Program in Industrial and Systems Engineering. Includes bibliographical references (p. 132-138).
607

Decontamination of Escherichia coli 0157:H7 and Salmonella in lettuce, chicken, and apples by chlorine dioxide and ultrasound

Xu, Chuanling, Huang, Tung-Shi. January 2005 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.
608

Development of a bio-preservation method for extended shelf-life cook-chill systems /

Rodgers, Svetlana. January 2003 (has links)
Thesis (PhD) -- University of Western Sydney, 2003. / "A thesis submitted for degree of Doctor of Philosophy, Centre for Advanced Food Research, School of Science, Food & Horticulture, University of Western Sydney, Hawkesbury campus, Richmond, Australia, January 2003" Bibliography: leaves 199-227.
609

Haemostatic changes in plasma for transfusion during preparation and storage /

Suontaka, Anna-Maija, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.
610

'Waiter! There's a fly in my soup - or is that a cockroach?': the moral panic of dirty restaurants in the city of Toronto, Canada /

Leung, Cherie January 1900 (has links)
Thesis (M.A.) - Carleton University, 2005. / Includes bibliographical references (p. 68-74). Also available in electronic format on the Internet.

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