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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.
11

Development of the MINITEL peripheral port adaptor (MPPA)

Strauss, Johann January 1992 (has links)
Thesis (M.Diploma in Electrical Engineering)--Cape Technikon, 1992 / This thesis describes how an adaptor board was developed to enable serial devices, such as modems and serial printers operating on RS-232 signals, to be used in conjunction with the MINITEL terminal. Furthermore it enables parallel Centronix interfaces to be Used in conjunction with the MINITEL terminal. The revolutionary 87C751 microprocessor was fully researched, and implemented in the project. Two marketable products emerged during the course of the project: • 1. The 8031-processor solution 2. The 87C751-processor solution
12

The disk storage system of the High Level Software Engineering Workstation (HLSEW)

Holt, Russell J. January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
13

Effects of neutral posture on muscle tension, pain and performance for computer users

Dowler, Elizabeth , Safety Science, Faculty of Science, UNSW January 1998 (has links)
This study focuses on developing a new approach to seated work positions. It was conducted on 67 office workers who use the Video Display Terminal (VDT) as a major function of their working day. Muscle tension was measured by surface electromyography when subjects were asked to adopt four selected working postures. Pain was measured before and after ergonomic intervention on the Nordic scale, which was modified for this study. Performance was measured on timed typing tests. A psychosocial questionnaire was used to determine influences of job demands, and a diagnostic assessment was performed to determine symptoms and pre-existing musculoskeletal conditions. Furniture was used to place subjects in desired positions during the clinical testing sessions and the extended intervention period. The chair seat pan was adjusted to a forward tilt to promote a lordotic curve of the low back, resulting in an erect upper body and upright head position. The desk and keyboard were adjusted to the proper height for each worker. A neutral wrist position was obtained by lowering and tilting the keyboard away from the user. Results revealed muscle tension scores in the upper trapezius and forearm extensors were significantly reduced when the workers were placed with the head in a midline position, with forward-tilting seating and with use of a negative sloping keyboard tray. Subjects reported low pain scores at pretest so no changes were noted after intervention. Loss of control over job elements, lack of job satisfaction, and fear of job loss were related to an increase in muscle tension. Only fear of job loss correlated to increased pain levels. There was no relationship between any of the job demand factors and performance.
14

A influencia da altura da tela do computador na ocorrencia da dor cervical / The influency of screen height of computer in ocurrence of neck pain

Roza, Fernanda Albieri Marchi Lopes 18 February 2008 (has links)
Orientador: Satoshi Kitamura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T11:10:12Z (GMT). No. of bitstreams: 1 Roza_FernandaAlbieriMarchiLopes_M.pdf: 2315417 bytes, checksum: 5134e985d650d5e2597bd5c8cddcedb7 (MD5) Previous issue date: 2007 / Resumo: A literatura nacional e principalmente internacional consultada, apresenta muitos desacordos sobre a altura mais apropriada da tela do computador, em relação à altura dos olhos do operador, visando propiciar ao usuário, melhores condições de trabalho. Alguns autores, associações e organizações vinculadas à ergonomia sugerem que o topo da tela do computador deva estar na linha dos olhos do indivíduo ou levemente para baixo. Através do presente estudo pretende-se propor um novo posicionamento da tela do computador, visando um melhor posicionamento para a coluna cervical, de modo que sua curvatura fique a mais fisiológica possível; e analisar sua influência na sintomatologia da região cervical. O método utilizado constou de três etapas: (1) aplicação de um questionário sobre sintomas, utilizando uma escala analógica visual (1 a 10), na qual o indivíduo assinalou o seu nível de dor; em três regiões do corpo que mais o incomodava ao utilizar o computador; (2) a medição para determinar a altura dos seus olhos em relação à parte central da tela e (3) aplicação do mesmo questionário, após um período de 90 dias de observação, para que se pudesse avaliar a eficácia da intervenção em relação à dor, quanto à sua localização e à sua intensidade. O estudo foi realizado nos setores administrativos de duas empresas. O ¿grupo intervenção¿ (empresa A) com um total de 24 sujeitos (15 mulheres e 9 homens), e média de idade de 30.2(DP=9.4); recebeu a orientação e a intervenção ergonômica (alteração da altura da tela do computador). O ¿grupo controle¿ (empresa B), com um total de 20 sujeitos (7 mulheres e 13 homens), e média de idade de 31.6(DP=7.1); recebeu a orientação ergonômica do posto de trabalho, sem alterar a altura da tela. A intervenção permaneceu em vigor durante um período aproximado de três meses em que o indivíduo desenvolveu o seu trabalho habitual normal. No final do período, os dados do questionário e da escala analógica visual antes e depois da intervenção foram registrados através do programa computacional SAS (Statistical Analysis System). Os resultados mostram que houve queda significativa na média da medida da dor das dez áreas analisadas (cervical, ombros, dorsal, cotovelos, antebraço, lombar, punhos/mãos/dedos, quadris e coxas, joelhos e tornozelos/pés), sendo semelhantes estatisticamente nas duas empresas. A região cervical apresentou valores médios maiores (sem significância estatística) do declínio da medida da dor na empresa A; mas com diferença estatisticamente significante entre homens e mulheres (p<0.05).Por outro lado,observou-se que não há associações do nível de dor com as faixas etárias e o uso do computador por dia. Os resultados corroboram para demonstrar os benefícios da intervenção ergonômica em postos de trabalhos informatizados, principalmente na minimização dos desconfortos músculo esqueléticos e num ambiente mais confortável e adequado para o trabalho / Abstract: Considering both national and international researched literature, one can notice several disagreements about the most appropriate height of the computer screen in relation to operator eyes' level, being here the target to provide better working conditions to the user. Some authors, associations and organizations suggest that the top of the computer screen should be at the line of the person¿s eyes, or slightly down.This study proposes a new position of the computer screen so that the curvature of the cervical spines is the most physiological as possible. F Furthermore, it, intends to analyze the influence of the symptoms of the cervical region. The method applied consisted of tree phases:(1) a survey on the symptoms, using a vision analogical scale (1 to10) in which the person mentioned his pain level in three regions of his body where computer disturbed him the most while using it;(2) the measurement to determine the level of the eyes related to the central spot of the screen;(3) the application of the same survey, after 90 days of observation, so to evaluate the effectiveness of the intervention in relation to the pain, as well as its location and intensity. The study was done in the administrative sectors of two enterprises. The ¿intervention group¿(Company A) with a total of 24 persons (15 women and 9 men) whose age average of 30.2(SD=9.4)received the guidance and ergonomic intervention by changing the level of the computer screen. The ¿control group¿(Company B) with a total of 20 persons(13 women and 7 men )whose age average of 31.6(SD=9.4)received the guidance of ergonomics for their workstation, without changing the level of the screen. The intervention remained under effect for approximately three months during which the persons did their usual and normal work. At the end of the period both the survey data and the usual analogical scale were recorded by a computer software called SAS (Statistical Analysis System), before and after the intervention. The results showed that there was significant reduction in the average measurement of the pain of the ten analyzed areas ( cervical, shoulder, dorsal,elbow,forearm,back,wrists,hands, fingers, hips and thighs, knees and ankles, feet)being statistically similar for both companies. The cervical region results showed higher average values (no statistical significance) of reduction in the extent of pain in Company A , but with statistically significant differences between men and women(p>0.05).On the other hand, it was observed that there is no association between the pain level and the different ages of the users and the daily use of computer. The results confirm the benefits of ergonomic intervention at computer work, mainly to minimize the muscle and skeletal discomforts in a more comfortable and appropriate environment for the job / Mestrado / Epidemiologia / Mestre em Saude Coletiva
15

A human factors evaluation of selected touch entry devices

Schulze, Lawrence John Henry January 1983 (has links)
Five commercially available touch entry devices (TEDs) were the  subject of a four-phase comprehensive assessment. Phase I consisted of the quantification of CRT-TED optical quality involving photometric measurements. Phase II involved the measurement and analysis of interactive operator performance in three generic tasks. Phase II was followed by the recording of subjective assessments of TED utility (Phase III). In Phase IV correlational analyses were conducted to relate CRT-TED system optical quality to the interactive performance measures and subjective assessments of TED utility collected in Experiment 1 of Phases II and III. A methodology for determining display quality of CRTTED systems in a quantitative manner as well as the operational and subjective utility of TEDs is presented. The results point out that large difference in resolution and noise levels exist among the various TEDs examined. Four of the devices tended to reduce overall display resolution and three reduced display noise levels. Large differences in interactive operator performance scores and ratings of subjective utility exist as well. There is some relationship between CRT-TED optical quality and both operator performance and subjective assessments of TED utility. Moreover, the suggested quantifications of the findings should facilitate comparisons among other touch entry device systems. / M.S.
16

Display spatial luminance nonuniformities: effects on operator performance and perception

Decker, Jennie Jo January 1989 (has links)
This dissertation examined the effects of display spatial luminance nonuniformities on operator performance and perception. The objectives of this research were to develop definitions of nonuniformity, develop accurate measurement techniques, determine acceptable levels of nonuniformities, and to develop a predictive model based on user performance data. Nonuniformities were described in terms of spatial frequency, amplitude, display luminance, gradient shape, and number of dimensions. Performance measures included a visual random search task and a subjective measure to determine users' perceptions of the nonuniformities. Results showed that users were able to perform the search task in the presence of appreciable nonuniformities. lt was concluded that current published recommendations for acceptable levels of nonuniformities are adequately specified. Results from the subjective task showed that users were sensitive to the presence of nonuniformities in terms of their perceptions of uniformity. Specifically, results showed that as spatial frequency increased, perceived uniformity ratings increased. That is, users rated nonuniformities to be less noticeable. As amplitude and display luminance increased, the users' ratings of perceived uniformity decreased; that is, they rated the display as being farther from a uniform field. There were no differences in impressions between a sine and triangle gradient shape, while a square gradient shape resulted in lower ratings of perceived uniformity. Few differences were attributed to the dimension (1-D versus 2- D) of the nonuniformity and results were inconclusive because dimension was confounded with the display luminance. Nonuniformities were analyzed using Fourier techniques to determine the amplitudes of the coefficients for each nonuniformity pattern. These physical descriptors were used to develop models to predict users' perceptions of the nonuniformities. A few models yielded good fits of the subjective data. lt was concluded that the method for describing and measuring nonuniformities was successful. Also, the results of this research were in strong concurrence with previous research in the area of spatial vision. / Ph. D.
17

3D measurement of cervical and thoracic postural dynamism in sitting : a pilot study

Fourie, Sarie Marissa 12 1900 (has links)
Thesis (MScPhysio)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The aim of this study was to improve the measurement of postural dynamism in the sitting position using a three-dimensional (3D) motion analysis system. The primary objective was to describe pilot data for postural dynamism of the cervical and thoracic spines while working at a desktop computer. The secondary objective was to refine the process of posture measurement and analysis by decreasing data processing time. Certain factors in 3D motion analysis can lead to an increase in gaps in data collected during trial capture, which in turn will lead to a longer time of data processing. In the first phase of this study, a number of such factors were identified and altered. A series of pilot studies was performed to test the improvement of data processing time when altering these factors. In the first two pilot studies, camera and tripod positionings were explored and refined, workstation layout and anatomical landmark marker placement were investigated, and optimal capture frequency was established. In both these pilot studies, outcomes were established by means of trial and error by experimenting with a variety of different options for the different outcomes. In the third pilot study, computer software which provides computer tasks for the participant during primary trial capture was tested. Two independent computer users performed all the activities as per software, after which they were required to give oral feedback and suggestions on improvement in terms of user friendliness. The objective of the fourth and final pilot study was to include all of the outcomes from the preceeding pilot studies and attempt a trial run of the actual data collection process. A study participant with no affiliation to the research project was used and a complete trial run was performed after which the measurement process was deemed feasible. In the primary study, 18 student volunteers completed a sequence of computer tasks, including keyboard, mouse and reading activities. Prior to data capture, full range of motion of the thoracic and cervical spines were measured in three dimensions for every participant. Data capture took place for the full duration of performance of all computer activities. Outcome parameters for postural dynamism included true range of motion (degrees), proportional range of motion (percentage) and motion frequency (movement per minute) in all three planes of motion of the cervical and thoracic spines. Typing tasks were associated with biggest movement ranges and motion frequencies. Mouse activity was associated with the most stationary posture, exhibiting the least frequent movement as well as the smallest ranges of motion. The results from this study allow us to better understand the dynamic nature of posture, as well as postural dynamism associated with different computer tasks. This study provides a baseline for future research of 3D motion analysis of the sitting posture. It also marks the need for further research regarding ergonomics, use and potential alternatives in the computer workstation and input devices. / AFRIKAANSE OPSOMMING: Hierdie studie het ten doel gehad om die meting van posturale dinamisme in die sitposisie te verbeter deur middel van „n drie-dimensionele (3D) bewegingsanalisesisteem. Die primêre doelwit was om loodsdata te beskryf vir posturale dinamisme van die servikale en torakale werwelkolomme terwyl op „n rekenaar gewerk word. Die sekondêre doelwit was om die proses van postuurmeting en analise te verfyn deur die dataprosesseringstyd te verminder. Sekere faktore van 3D bewegingsanalise kan „n vermeerdering van gapings in ingesamelde data tot gevolg hê, wat weer kan lei na „n verlengde tydperiode van dataprosessering. In die eerste fase van hierdie studie is sulke faktore identifiseer en aangepas. „n Reeks loodsstudies is uitgevoer om die verbetering van dataprosesseringstyd te toets namate aanpassings aan hierdie faktore gemaak is. Tydens die eerste twee loodsstudies is verskillende kamera en driepoot posisionering ondersoek en verfyn, werkstasie uitleg en anatomiese baken merker plasing is ondersoek en die optimale dataversamelingsfrekwensie is vasgestel. In beide hierdie loodsstudies is die uitkomste vasgestel op grond van toets- en fouteer deur te eksperimenteer met „n verskeidenheid opsies soos van toepassing op die betrokke uitkomste. Tydens die derde loodsstudie is rekenaarsagteware getoets wat die rekenaaraktiwiteit vir die studiedeelnemers verskaf het tydens primêre data-insameling. Twee onafhanklike persone het al die aktiwiteite volgens die sagteware voltooi en het verbale terugvoer en aanbevelings gegee oor hoe om die program te verbeter. Die vierdie en finale loodsstudie het gepoog om al die uitkomste van die eerste drie loodsstudies in te sluit en „n toetsmeting te doen van die ware dataversamelingsproses. „n Onafhanklike studiedeelnemer met geen affiliasie tot die navorsingsprojek nie het „n toetslopie van die hele versamelingsproses gedoen en die metingsproses is haalbaar verklaar. Tydens die primêre studie het 18 student-vrywilligers „n reeks rekenaartake gedoen (insluitend sleutelbord en muisaktiwiteite sowel as „n leesopdrag). Voor die aanvang van dataversameling is die volle bewegingsomvange van die torakale en servikale werwelkolomme van elke deelnemer gemeet. Dataversameling is vir die volle durasie van die uitvoer van rekenaaraktiwiteite gedoen. Uitkomsparameters vir posturale dinamisme het die volgende ingesluit: Omvang van beweging (grade), proporsionele omvang van beweging (persentasie) en bewegingsfrekwensie (bewegings per minuut) in al drie bewegingsvlakke van die servikale en torakale werwelkolomme. Sleutelbord-aktiwiteite is geässosieer met die grootste bewegingsomvange en die meeste bewegingsfrekwensie. Muisaktiwiteit is geässosieer met die mees stasionêre postuur en het die heel minste gereelde beweging getoon in die algemeen. Die resultate van hierdie studie help om die dinamise natuur van postuur beter te verstaan, sowel as posturale dinamisme wat met verskillende rekenaartake verbind word. Die studie bied „n basislyn vir die toekomstige navorsings wat posturale dinamisme met verskillende rekenaartake meet. Dit merk ook die behoefte aan verdere navorsing aangaande ergonomika, gebruik en alternatiewe tot rekenaarwerkstasie en –toerusting.
18

An intelligent multi-terminal interface.

Peplow, Roger Charles Samuel. January 1987 (has links)
The document describes the development of a micro-processor based terminal multiplexer to connect four terminals to a standard Hewlett Packard series 1000 mini-computer. The project was required to fulfill the dual roll of both increasing the number of terminals that the HPI000 could support and of reducing the peripheral load on the host CPU. The final product occupied a standard 200mm square HP size interface card and used an 8085 micro-processor and several 8085 family peripheral chips to provide four full duplex serial channels and a high speed data link with the host. A multi-tasking executive was written to control the multiplexer software which was finally implemented as 15 independent tasks occupying 8 kilo-bytes of eprom. The software was written to perform all terminal interaction and editing in order to reduce the host CPU involvement to a single interrupt per record. The resultant interface proved capable of handling an aggregate throughput in excess of 4000 characters per second which was sufficient to cope with all four terminals running at 9600 bits per second, even when all four were transferring in burst mode. The interface also proved to be between five and eighteen times less demanding on the host than the two standard Hewlett Packard interfaces then available. When compared to the low cost HP12531 interface, the multiplexer increased the 9600b/s terminal handling capability of the host from 3 terminals to 52. / Thesis (M.Sc.-Electronic Engineering)-University of Natal, 1987.
19

The screen as boundary object

Lee, Hyun Jean. January 2009 (has links)
Thesis (M. S.)--Literature, Communication, and Culture, Georgia Institute of Technology, 2009. / Committee Chair: Mazalek, Ali; Committee Member: Bolter, Jay David; Committee Member: Do, Ellen Yi-Luen; Committee Member: Nitsche, Michael; Committee Member: Winegarden, Claudia R.
20

"Efeitos de um programa de exercícios no desconforto músculoesquelético dos segmentos corporais de operadores de telemarketing" / Effects of an exercise program on the body segments musculoskeletal discomfort of telemarketing operators

Lacaze, Denise Helena de Castro 21 June 2006 (has links)
Este estudo tem por objetivo avaliar o nível de desconforto, através da Escala Visual Analógica (EVA), o Mapa de Segmentos Corporais de Corlett e Bishop (MSC) e o Questionário de Fadiga de Chalder (EFC) em operadores de telemarketing. A coleta de dados foi realizada uma vez por semana, ao longo de 2 meses de aplicação do programa de exercícios. A análise estatística sugere diminuição do crescimento do desconforto postural nos dois grupos, sendo mais acentuada no grupo experimental. Foi observada também diminuição significativa dos níveis de EVA e redução da freqüência e da prevalência de segmentos doloridos no MSC, ao se comparar dados da primeira e da última semana do estudo realizado. Quanto à fadiga também houve melhora em todas as variáveis do questionário de Chalder, indicando presença de efeitos significativos na diminuição dos níveis de fadiga. Assim, os programa de exercícios mostraram-se efetivos para diminuir o desconforto músculo-esquelético e a fadiga entre os operadores de telemarketing / The objective of this survey is to assess the telemarketing operators discomfort and mental and physical fatigue at the airway company call center before and after applying an exercise program. The objective of this survey is to assess the telemarketing operators discomfort and mental and physical fatigue at the airway company call center before and after applying an exercise program. The body map of Corlett and Bishop with a visual analogic scale and the Chalder fatigue questionnaire was applied to 84 telemarketing operators from the experimental and control groups. The experimental group has attended a 10 minutes exercise daily session and the control group a 10 minutes daily rest break. The exercise showed that is more effective than a rest break to prevent discomfort development and is important to repetitive strain injuries prevention because discomfort is one of the main predictors of this group of diseases

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