Browsing by Subject "Ergonomics"
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Item Development of a system for collecting and maintaining anthropometric measurements for persons with dwarfism(2007-12) Ferguson, Bethany L.; Smith, James L.; Woldstad, Jeffrey C.; Kobza, John E.Every product or environment a person encounters should match their capabilities and limitations to maximize safety and efficiency, but the variety present in the human race makes a design which accommodates everyone difficult to achieve. It is especially difficult when the user population includes persons with dwarfism due to their extreme differences in body size and a vast lack of anthropometric information specific to dwarfs. To aid in achieving ergonomic design for little people, an anthropometric survey was performed using photographic methods on forty-nine little people. The analysis of the results showed that the dimensions were generally normally distributed and variation was greatly reduced when the subject population was limited to a single type of dwarfism. The data were used to create models based on highly correlated measurement pairs so that body measurements could be estimated as a proportion of total height when anthropometric data were not available. Finally, recommendations were made on how to improve on the anthropometric survey method and a database for maintaining current and future measurement data was proposed.Item Ergonomics and urban green infrastructure : understanding multifunctional social-environmental systems(2014-08) Rinas, Rebecca Jean; Sletto, Bjørn,Although urban green infrastructure [UGI] is increasingly characterized as an asset because it simultaneously serves critical social and environmental functions, few planning tools or research approaches exist where multiple functions are integrated into a systemic spatial analysis. Accordingly, this report examines the utility of ergonomics as a methodological approach to integrate the natural and social sciences and forge a deeper understanding of UGI multifunctionality. Five administrative districts in Dresden [Germany] were selected as a study area to carry out this analysis. Mixed methods were used to categorize and measure various social and environmental functions of UGI cases, and outcomes analyzed for spatial clustering in GIS. Results from this study provide strong evidence that combining social and environmental variables can significantly inform the way UGI networks are perceived and valued.Item Simulation of tossing - biomechanics and motor control(Texas Tech University, 2008-12) Ladavichitkul, Phairoat; Smith, James L.; Hsiang, Simon M.; Woldstad, Jeffrey C.; Ayoub, M. M.; Martin, Clyde F.Tossing tasks, a kind of manual material handling (MMH), extends from lifting tasks. Unlike lifting task studies, there were few reports studying tossing tasks in term of Biomechanics. In this study, the tossing tasks were studied in terms of Biomechanics and Fitts’ law, and the tossing tasks were also simulated based on the lifting task simulation. To validate the tossing task simulation, a 2×2×2×3 factorial experimental design (tossing distance, tossing height, weight of load, and tossing clearance) was established. Ten volunteer subjects were recruited from the students of Texas Tech University. A motion capture recorded their motion throughout their movement while doing the tossing tasks. The first analysis was the comparison between the tossing and lifting tasks in order to validate that the tossing task simulation can be guided by the lifting tasks simulation. The comparison analyses were considered the joint angle trajectories, the load trajectories and velocities, and the compressive and shear forces of the L5/S1 joint. The comparison showed that similarities between both kinds of tasks were found in the first half of the activity duration. On the other hand, dissimilarities between both kinds of tasks were found in the second half of the activity duration. The differences of the joint angle trajectories were found because of the different objective at the end of the tasks. Subjects slowed the load velocity before it impacted on the table while they increased the load speed before the load was released from their hands. Although similarities and dissimilarities between tossing and lifting tasks were found, the tossing tasks could be separated into three phases with four key postures (initial, load-close to body, aiming, and releasing postures) which was similar to the lifting tasks. Therefore, the next step of this study was the evaluation of the four key postures by using the mathematical models. The second analysis was the validation of the four key posture evaluations. The objective function used for evaluation was body balancing. The center of mass (COM) of subjects while doing the tossing tasks was investigated to validated the objective function. COM investigation showed that if none of the subjects had COM beyond their feet, then body balancing can be used as the objective function. All key postures were evaluated by using body balancing with the constraints. The constraints of the 1st, 2nd, and 3rd key postures were the interaction between the human and the load position while the constraints of the 4th key posture were the load movements before and after the 4th key posture. The load movement before the 4th key posture was considered as the linear movement. The load movement after the 4th key posture was considered as the projectile movement which was affected by the tossing distance, tossing height, weight of load, and target clearance. The tossing distance and height significantly affected the projectile time and the initial angle of projectile. In addition, the tossing clearance significantly affected only the initial angle of projectile. With regard to the compressive force, only the tossing distance significantly affected the maximum compressive force on L5/S1 joint in the releasing phase. Moreover, all factors significantly effected the movement time. These investigations were considered for the 4th key posture evaluation. Therefore, the four key postures could be connected together to simulate the tossing task movement. The final analysis in this study was the validation of the tossing task simulation, which was comprised of the optimization for the positions in time frame of the 2nd and 3rd key postures and then the connections of the joint angle trajectories. The optimization methods applied three different objective functions (maximize the hand movement smoothness, maximize the smoothness of the center of the gravity (COG) movement, and minimize the muscular utilization rate (MUR)) in order to find three different positions in time frame of the 2nd and 3rd key postures. The comparisons among three objective functions showed that the maximize the smoothness of the center of the gravity (COG) movement predicted the positions in time frame of the 2nd and 3rd key postures closest to the actual positions in time frame of the 2nd and 3rd key postures. To validate these optimization methods, all joint angle trajectories from four key postures were connected by using an 8th order polynomial equation. The validation results showed that hand movement smoothness was the best predictor for arm movement; however, body balance was the best predictor for trunk and leg movements. As regards to the whole body posture, hand movement smoothness should be considered to simulate tossing tasks, because the important part of the tossing task movement in this study was the upper extremities. Since the subjects stood at a fixed point (no stepping) while doing the tossing tasks, the movement of the lower extremities had low variation. In this case, the lower extremities might be not concerned for tossing task simulations. Unlike the lower extremities, the upper extremities moved in a wider range and faster speed, including more varieties of hand movement compared to leg movement. In addition, the varieties of tossing factors and weight of load affected the varieties of hand movement more than the leg movement. Therefore, the movement of upper extremities should be a major consideration which could be simulated by the hand movement smoothness.Item Space within : Frederick Kiesler and the architecture of an idea(2014-05) McGuire, Laura; Long, Christopher (Christopher Alan), 1957-From 1922-1942, the Austrian-American architect and designer Frederick Jacob Kiesler (1890-1965) designed architecture based on the idea that it must complement the physiological and psychological processes of the human body. In order to reconcile the technological changes wrought by industrialized production with the need for structures that promoted human health, he developed an inspired model for interactive design. His formative experiences in Europe working with De Stijl and the G-Group, along with his exposure to Central European examples of architecture, art, and science set the agenda for his later works. Yet he never stopped experimenting with new concepts that would bolster his essential philosophy of body-generated space. After he immigrated to the United States in 1926, Kiesler’s pursued his ideas about physiological and psychological architecture within a new cultural milieu and a network of encouraging personal connections. He forged relationships with a sympathetic community of émigré industrial designers and architects who promoted his efforts to integrate modern technology with new design idioms. During his first fifteen years in New York City, Kiesler looked to contemporary science as a way to advance a model of flexible architectural design. He also worked at the cutting edge of industrial design research and was an early protagonist of human factors engineering methods. His body-centered methodology stood in opposition to aesthetic and reductive approaches toward modernism and functionalism. Instead of designing according to a priori determinations of what was functional and what was not, Kiesler’s functionalism was based on an iterative design practice that would reveal progressively more useful and universally applicable forms.