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One of the major obstacles to performance evaluation studies is the definition of a representative or accurate workload. User scripts, a detailed description of user activities to specify an interactive workload, can be used as input for remote terminal emulators as well as a representation of an interactive workload the users impose on a system. User scripts are often based on the widely accepted user behaviour model 'LIST-MODS-RUN'. A method of analysis is described which suggests that this user behaviour is not realistic. More accurate models are given to describe user behaviour at system command language level. It is also studied how different users groups adapt to different loads. The results are then used to define a workload model. An automatic workload genrator is described to generate workload models in form of user scripts ready for execution 'on ERTE which is a system designed to exert interactive workloads on a multiaccess system. Experimental runs with ERTE demonstrate the accuracy of the model and provide the basis for more realistic performance measures on EMAS and the development of ERTE.

Zugl. Diss.

Doctor of Philosophy / Department of Special Education, Counseling and Student Affairs / Judy Hughey / College counseling has been a unique profession among the helping professions that seeks to provide mental health and academic support to college students. One vocational danger for college counselors has been the onset of burnout. The loss of resources leading to burnout, as explained by the Conservation of Resources theory, may have been connected to today’s higher education administrative position of performing more responsibilities with less staffing. This research study examined the relationship between work duties assigned to college counselors, as measured by the College Counselor Activity Rating Scale, and the level of burnout for those counselors, as measured by the Shirom-Melamed Burnout Measure. The first five hypotheses examined the relationship between burnout and non-counseling duties by utilizing a hierarchical multiple regression analysis with various tests of mediation and moderation. The sixth hypothesis explored the assertion that college counselors at small institutions of higher education (institutional enrollment less than 5000 students) are more likely to engage in non-counseling duties. Members of the American College Counseling Association were recruited to serve as the population sample frame for the study. Because no instrument existed to measure counseling and non-counseling duties for college counselors, the College Counselor Activity Rating Scale was developed as a part of the study. Validation procedures were utilized in the form of an expert panel and pilot study for the College Counselor Activity Rating Scale. Of the six null hypotheses, all six were retained with limited power. Further analysis showed statistically significant relationships between burnout, perceived workload, and meaningful work. In addition, three non-counseling duties items, all related to administrative duties, were statistically significantly related to burnout. The key findings, implications and recommendations for future research were discussed.

The objective of the present study was to investigate and compare the human responses to two load carriage tasks performed with three different load masses and on three different gradients. The task of carrying hydrogel in one hand was observed in a silviculture industry and crude physiological and perceptual responses were measured. This task was simulated in a laboratory setting together with a suggested intervention of backpack carriage. Eighteen conditions were established which consisted of the two modes of carriage and a combination of three load masses (9kg, 12kg and 15kg) and three gradients (5%, 10% and 15%). Twenty eight Rhodes University female students comprised the sample and the experimental procedures were conducted on a Quinton treadmill. Each participant was required to complete nine of the eighteen conditions which were each four minutes in duration. Postural changes were assessed using lateral and posterior digital images taken at the second and fourth minute and compression and shearing forces were estimated with the ErgolmagerTM Physiological responses (heart rate, ventilation and metabolic responses) were measured continuously with the Quark b² and perceptual responses ('central' and 'local' RPE) were measured every minute during the experimentation and body discomfort was rated at the completion of each condition. Overall responses revealed that hand carriage (146 bt.min⁻¹ , 25.09 mIO₂. kg-l.min⁻¹) was generally found to be more physiologically stressful than backpack carriage (130 bt.min⁻¹, 22.15 mIO₂.kg⁻¹ .min⁻¹) independent of load mass and gradient. Physiological responses were higher (113 bt.min-1 to 174 bt.min⁻¹ ) in responses to increasing gradient as opposed to increasing load mass (104 bt.min-1 to 153 bt.min⁻¹ ) for both backpack and hand carriage. Categorisation using the guidelines of Sanders and McCormick (1993) allowed for classification of conditions, with respect to physiological responses, into 'moderate', 'heavy' and 'very heavy' stress. For almost all of the physiological responses the majority of conditions which were classified as 'moderate' were backpack carriage conditions and the conditions classified as 'very heavy' were mostly hand carriage conditions. In terms of postural responses hand carriage resulted in more strain and greater compression and shearing forces on the spine. In terms of the compression forces increasing gradient had a greater affect on backpack carriage (681 N to 935 N) compared to hand carriage (570N to 793N). In contrast, increasing load mass had a larger affect on hand carriage postures and compression forces (751 N to 935N) in comparison to backpack carriage (723N to 780N). Shearing forces were found to be worse in hand carriage conditions overall. Although participants generally underrated perceived exertion in relation to cardiorespiratory responses, these perceptions revealed that backpack carriage, with a mean 'central' RPE of 12 compared to 11 for hand carriage, was somewhat preferred to hand carriage and that increasing gradient was perceived to be marginally more straining than increasing load mass.

Aversion is a complex phenomenon that arises over time through performance of cognitively demanding tasks and has been associated with the mechanisms of mental fatigue and compensatory control. However, little is known about this sensation to dissociate from the task at hand and the causation thereof. It is apparent that aversion is a negative state for the operator and could result in decreased performance and productivity. Through identification of factors that contribute to aversion when performing cognitively demanding tasks, recommendations to reduce design deficits may be employed to promote worker wellbeing and further advance performance and productivity. The current study examined possible factors that may influence aversion experienced through execution of cognitive tasks. A subsequent aim of this study was to assess a possible cause of aversion. The cause of aversion was hypothesized to be related to efficiency, namely the perception of efficiency when performing tasks and actual efficiency calculated through performance of tasks in relation to the expenditure of effort. Four investigations were undertaken with a non-repeated design between investigations and a repeated design within investigations. The first investigation was an analysis of the effect that stimulus cycling had on the aversion experienced. This consisted of a proof reading task with two conditions varying in the repetitiveness of the text, therefore, allowing an analysis as to how aversion is altered by the provision of a new stimulus to the participants. Investigation two investigated the effect that task difficulty imposed on aversion experienced. This comprised of two conditions with varied difficulty that were implemented through a driving simulator tracking task with difficulty altered by the width of the driving lane. The effect of performance feedback on the aversion experienced towards a task was the focus of the third investigation. The effect on aversion experienced was assessed through a driving simulator tracking task with a condition providing feedback of performance to participants and a condition with no knowledge of performance. The final experiment evaluated the effect of task alternations on aversion. This experiment was conducted through alternations between a driving simulator tracking task and a choice reaction task. The choice reaction tasks required participants to identify critical and non-critical stimulus. Four conditions were required for this experiment and were made up of two conditions where there was provision of alternation that varied in frequencies between the two tasks (medium alternation condition and fast alternation condition) and two conditions where no alternations were instated (driving simulator task condition and choice reaction task condition). Separations between all testing conditions were three or more days apart with sixty participants distributed between the investigations. Test duration of each condition was 30 minutes. Subjective data was recorded throughout investigations for all conditions in the form of aversion, subjectively perceived efficiency and rate of perceived exertion. Objective data was collected in the form of physiological responses and performance of tasks for the analysis of objective efficiency. For factors influencing aversion analysis, no differences in aversion experienced were found for the task difficulty and performance feedback investigations. Aversion was found to be less for the changes imposed through the task cycles and task alternation investigations. This concludes that aversion is aggravated through monotonous tasks and by a change of the stimulus or the structure of the cognitive tasks provided to operators; aversion can be alleviated. The results for the cause of aversion analysis found no difference in objective efficiency over time, with a subsequent decrease in perceived efficiency associated with the increasing aversion. Inference from these findings suggest that aversion cannot be attributed to objective inefficiency of task performance, however it can further be assumed that perception of actual efficiency is inaccurate. Perception of efficiency however had a large influence on the sensation of aversion. Aversion is seen to be more of a product of time on task, however whether this is mechanism of fatigue or compensatory control is still to be determined.

O objetivo geral desta tese foi avaliar o impacto do sistema de trabalho em turnos nos trabalhadores de dois setores de uma indústria de filmes e embalagens flexíveis para alimentos que opera em três turnos de trabalho fixos, considerando o cronotipo do trabalhador. Foi feita a caracterização do sexo, experiência profissional, faixa etária e cronotipo (por meio de dois questionários) de 42 trabalhadores do setor de Impressão e 43 do setor de Corte/Solda nos três diferentes turnos e avaliadas as cargas física e mental (com ferramentas subjetivas e indicadores fisiológicos) das atividades realizadas e as demandas ergonômicas dos Construtos: Ambiente, Posto de trabalho, Organização de Trabalho, Conteúdo do Trabalho, Empresa e Risco/Dor. Foram coletados parâmetros ambientais (ruído, temperatura e umidade) para identificar o seu grau de impacto sobre o desempenho do trabalhador. Embora dentro dos limites legais, principalmente o ruído e a temperatura apresentaram baixa satisfação nos dois setores. Os resultados estatísticos apontaram diferenças entre os resultados em função dos setores (o setor de Impressão com maiores demandas do que o Corte/Solda), turnos (o turno noturno com mais demandas) e influência do cronotipo discrepante ao horário de turno. Os trabalhadores com cronotipo desajustado ao horário do turno tendem a perceber mais negativamente a carga de trabalho, tendem à menor satisfação com vários itens de demanda ergonômica e a sentir maior intensidade de dor. Houve variação dos indicadores fisiológicos (nível de cortisol salivar, catecolaminas urinárias, pressão arterial, frequência cardíaca e consequentemente, do percentual da máxima capacidade aeróbica) dependendo do indivíduo e eles foram consistentes com a avaliação subjetiva de carga de trabalho. Os resultados deixam claro que os trabalhadores sabem a que horas querem iniciar e finalizar o trabalho (que são compatíveis com o cronotipo) e não gostam de trabalhar em turno, mas se o turno for necessário, a preferência é por turno fixo. A proposta é que no caso de trabalho em turno, seja considerado o cronotipo do trabalhador e que este tenha autonomia para escolher o turno, pois necessidades familiares e sociais também são fatores de decisão nesta escolha. / This thesis aimed to evaluate the impact of shiftwork on the workers of two sectors of a flexible packaging manufacturer which operates in three shifts, considering the cronotype of the worker. 42 workers from the three shifts of the Imprint sector and 43 from the Cutting/Welding sector were characterized according to sex, professional experience, age and cronotype (based on two questionnaires). Both mental and physical workload were evaluated using subjective tools and physiological parameters. The satisfaction with their work (i.e., the Environment, the Workstation, the Work Organization, the Work Content, the Enterprise and the Risk of pain) was evaluated by questionnaire. Environmental data (noise, temperature and humidity) were gathered for evaluation of their impact on the workers. Although within the law limits, noise and temperature were not satisfactory in both sectors..The statistical results showed differences between the sectors (the Imprint one with more esrgonomic demands), among the shifts (the night one with more ergonomic demandas) and influence of the worker cronotype. The workers whose cronotype were not compatible with their shiftwork tend to be less satisfied with their work, tend to feel more pain and overloaded. The physiological parameters (hormonal levels of cortisol, urinary cathecholamines, arterial pressure, heart rate and consequently the percent of maximum aerobic work capacity) varied with the individual and were consistent with the subjective workload evaluation. The results showed that the workers know their best work time (which is compatible with their cronotype), they do not like shiftwork but if it is necessary, they prefer the fixed shift. The proposal is that if shiftwork is necessary, the worker cronotype has to be considered and he/she should choose the shift because familiar and social issues are also part of this choice.

Um dos principais objetivos da ergonomia é ter uma carga de trabalho adequada, buscando a melhoria dos níveis de conforto, satisfação, eficiência e segurança no trabalho, caso contrário, sua inadequação pode influenciar a saúde e segurança do trabalhador, além de afetar a organização. O objetivo geral deste estudo é identificar as causas raiz de uma carga de trabalho inadequada com intuito de compreender os fatores influentes e suas interligações visando melhorar a condição de saúde e segurança dos trabalhadores. Os objetivos específicos são: (i) entender e definir as dimensões da carga de trabalho através de uma revisão sistemática de literatura; (ii) identificar os fatores influentes centrais, ou seja, causas raiz, da inadequação da carga de trabalho através da análise de uma revisão sistemática utilizando ferramentas do Processo de Pensamento; (iii) avaliar a carga de trabalho e suas inadequações de forma participativa, através da mensuração desta e da identificação de suas causas raiz em uma empresa de manufatura. Para alcançar cada um dos objetivos o presente trabalho foi estruturado na forma de três artigos, associados a cada um dos objetivos específicos. Assim, o trabalho foi composto por uma revisão sistemática de literatura (Artigo 1), análise de uma revisão sistemática (Artigo 2) e um estudo de caso aplicado (Artigo 3). O primeiro artigo entendeu e definiu as dimensões da carga de trabalho. No segundo, identificou-se os fatores influentes centrais da inadequação da carga de trabalho através de uma revisão sistemática. Já no terceiro artigo, foi realizado um estudo de caso, composto pela avaliação da carga de trabalho através da NASA TLX, demonstrando a carga de trabalho de máximo risco (carga de trabalho geral). Neste também mensurou-se, de forma participativa, os fatores centrais desta inadequação através de ferramentas do processo de pensamento. O resultado final permitiu perceber poucos estudos definindo carga de trabalho entre artigos empíricos, não havendo uma definição padrão. Percebeu-se que o foco dos artigos não são na abordagem da adequação desta carga de trabalho. Permitiu-se identificar as causas raiz de uma carga de trabalho inadequada, propiciando uma análise profunda das relações gerais do problema, através da lógica causa e efeito, incluindo os fatores influentes e suas interligações. / A major goal of ergonomics consists in having an adequate workload in order to improve levels of comfort, satisfaction, efficiency and safety. Otherwise, its inadequacy can influence health and worker’s safety and affect the organization. The aim of this study is to identify the root causes of inadequate workload in spite of understanding the influencing factors and their interconnections to improve the workers health and safety. The specific objectives are: (i) understand and define the dimensions of the workload through a systematic literature review; (ii) identify the substantial influencing factors (root causes) of the inadequacy of the workload by analyzing a systematic review using Thinking Process tools; (iii) evaluate the workload and its inadequacies in a participatory manner, by measuring and identifying their root causes in a manufacturing company. To achieve each objective, this study was structured with three articles associated with each of the specific objectives. Therefore, the work is consisted of a systematic review of the literature (Article 1), analysis of a systematic review (Article 2) and an applied case study (Article 3). The first article understood and defined the dimensions of workload. In the second, we identified the major influencing factors of inadequate workload through a systematic review. In the third article, we conducted a case study, comprising the assessment of workload through the NASA TLX, demonstrating the maximum risk workload (overall workload). The end result allowed us to perceive few studies defining workload between empirical articles, there is no standard definition. It was felt that the focus of the articles are not in addressing the appropriateness of this workload. Allowed to identify the root causes of inadequate workload, providing a thorough analysis of the general relations of the problem, by logical cause and effect, including the influential factors and their interconnections.

abstract: A benchmark suite that is representative of the programs a processor typically executes is necessary to understand a processor's performance or energy consumption characteristics. The first contribution of this work addresses this need for mobile platforms with MobileBench, a selection of representative smartphone applications. In smartphones, like any other portable computing systems, energy is a limited resource. Based on the energy characterization of a commercial widely-used smartphone, application cores are found to consume a significant part of the total energy consumption of the device. With this insight, the subsequent part of this thesis focuses on the portion of energy that is spent to move data from the memory system to the application core's internal registers. The primary motivation for this work comes from the relatively higher power consumption associated with a data movement instruction compared to that of an arithmetic instruction. The data movement energy cost is worsened esp. in a System on Chip (SoC) because the amount of data received and exchanged in a SoC based smartphone increases at an explosive rate. A detailed investigation is performed to quantify the impact of data movement on the overall energy consumption of a smartphone device. To aid this study, microbenchmarks that generate desired data movement patterns between different levels of the memory hierarchy are designed. Energy costs of data movement are then computed by measuring the instantaneous power consumption of the device when the micro benchmarks are executed. This work makes an extensive use of hardware performance counters to validate the memory access behavior of microbenchmarks and to characterize the energy consumed in moving data. Finally, the calculated energy costs of data movement are used to characterize the portion of energy that MobileBench applications spend in moving data. The results of this study show that a significant 35% of the total device energy is spent in data movement alone. Energy is an increasingly important criteria in the context of designing architectures for future smartphones and this thesis offers insights into data movement energy consumption. / Dissertation/Thesis / Masters Thesis Computer Science 2014

abstract: This study examined the impact of Situation Presence Assessment Method (SPAM) administration on air traffic control (ATC) students’ task workload and performance in high-fidelity ATC simulations. ATC students performed high-fidelity en-route simulations in two conditions: baseline conditions (without SPAM questions) and SPAM conditions. The data collected show that while workload in the two conditions were not significantly different, there was a trend of higher mental workload in SPAM conditions than in baseline conditions. Performance immediately following SPAM questions was revealed to be poorer than that preceding the SPAM questions and that over the equivalent time periods in the baseline conditions. The results suggest that a "Ready" signal before a SPAM question may not be enough to eliminate the impact of SPAM administration on ATC students’ workload and performance in high-fidelity en-route simulations. / Dissertation/Thesis / Masters Thesis Technology 2016