Unsafe exits from dementia care units present problems for residents and pose ethical dilemmas for caregivers. The purpose of this experimental research was to determine whether visual barriers reduced the exiting behavior of residents in a long-term care facility. A visual barrier was defined as one that appeared to be an obstruction, but that did not impede egress through the door. The study was conducted in a 30-bed dementia care unit and was limited to the emergency exit door where an alarm sounded each time the panic bar was touched. An “exit" was defined as a resident touching the panic bar and sounding the alarm. The sample consisted of 3 females and 6 males who attempted to exit the unit at least once during baseline condition. All residents were diagnosed with some form of dementia. The tests were conducted under three visual barriers and one baseline condition. Each condition was observed for seven days from 2:00 to 4:00 p.m. The schedule was as follows: Baseline Condition: No experimental manipulation was used. This observation provided a comparison for the three test conditions. Test Condition 1: Mini-blinds that covered the glazing of the door. Test Condition 2: Cloth panel that covered the panic bar of the door. Test Condition 3: Both the mini blind and the cloth panel. During baseline collection, 9 residents triggered the alarm for a total of 120 attempted exits. Test condition 1 decreased exiting to 73 attempts. During test condition 2, 5 attempted exits occurred, and 18 attempted exits occurred during test condition 3. Statistical analysis included Friedman’s Rank test for correlated samples and Wilcoxon Sign Rank tests for treatment versus control comparisons. Test conditions 2 and 3 significantly reduced attempted exits while test condition 1 was not statistically significant. In conclusion, visual barriers were a safe and effective method for deterring resident exiting for this particular nursing home. / Master of Science

Low-back pain and injury claims account for a large number of occupational illnesses each year. In the railroad industry, many maintenance and operation activities require a high degree of manual labor, often resulting in increased stress on the lowback. One of the most common functions of railroad yardmen is the setting and releasing of railcar hand brakes. A static three-dimensional low-back biomechanical model was developed to estimate the levels of compressive force on the L3/L4 spinal joint that existed in subjects during an experiment that simulated the hand brake setting task. We recorded three-dimensional body posture and resultant forces at the hands for analysis by the model. The model resolved the external forces acting on the body to a resultant moment about L3/L4 and then employed an optimization algorithm to estimate the internal lumbar muscle forces generated to resist the external forces. The muscle forces and external forces were added to arrive at a prediction of compressive force at L3/L4. The experiment investigated the effects of general body posture, left hand grip, subject anthropometry, and hand brake torque level upon predicted compressive force at L3/L4. An analysis of variance revealed that compressive force was significantly affected by each of the experimental variables. Additional analyses at subjects' maximum voluntary torque levels indicated that compressive force would exceed NIOSH guidelines for low-back compressive force, especially in males. Predicted L3/L4 compressive force at maximum torque ranged from an average of 2350N in small females to an average of 7485N for large males. We then used regression analysis to predict brake torque levels that would cause compressive force to exceed the NIOSH (1981) recommended maximum of 3400N. Based on the prediction methods used, hand brake torques of 40 to 80 Nm would be likely to cause compressive force to exceed this maximum. / Master of Science

A common concern for people using computer databases is becoming "lost" within the complex hierarchy of entries. Most direct manipulation interface design guidelines suggest designers should include a feature for “undoing” user inputs (Smith and Mosier, 1986). In the case of a database, undo translates to backtracking support. The first purpose of this research was to confirm that computer-supported backtracking tools reduce navigation time over manual backtracking. The second purpose was to compare navigation times among a subset of backtracking tools. The third purpose was to determine if users prefer to use one or more backtracking tools significantly more than others. Four backtracking tools were developed by crossing two factors: History (history list vs no history list) and Level (component vs entry). History list indicates the user may view a chronological listing of nodes that have been viewed and directly select a destination node. No history list means the user must backtrack through each visited node with no shortcuts. Component indicates the backtracking tools operate only at the lowest level, or smallest definable node, of the tree-like database structure. Entry means that backtracking occurs at the higher parent node. Thus, multiple components make up an entry . In addition to the four computer backtracking tools, overall navigating and manual backtracking was done using a hierarchical Table of Contents. The tools were evaluated in an experimental, hierarchical, direct-manipulation database. Trials were conducted in the form of a multiple-choice information retrieval task. The independent variables included the backtracking tool (four-computer supported, one-manual) and the backtrack Task Length. The dependent measures included navigation time, the frequency with which the computer tool was used over manual backtracking (Table of Contents), and questionnaire responses. The results of this study provided some of the first solid support for the many guidelines that have been written recommending user recovery, or undo support. Backtracking with any of the four computer-supported tools resulted in a significantly smaller navigation time than manual backtracking using the Table of Contents. Subjects using either of the entry tools had consistent backtracking times across trials regardless of backtrack task length. When provided with a history list, subjects in the entry condition had significantly smaller navigation times than subjects in the component condition. Users did not show any differences between computer tools in rated efficiency, ease of use, or objective preference measures. / Master of Science

The reported study measured the effects of alcohol on risk-taking 511 a penalty/incentive system. Subjects read scenarios involving industrial tasks and accidents from a video screen. Each scenario had a point value associated with it. Subjects had to decide whether they were willing to perform the task if there was a specified probability of having an accident. They would win points for successfully performing the task, but lose points for having an accident. Their goal was to score as many points as possible. The points won were used to buy tickets for one of two $100.00 drawings. Those with the most tickets had the highest probability of winning the drawing. This motivator was used to stimulate cautious decision-making about taking risks. Prior to participation in the task, subjects ingested a mixture of orange juice and 80-proof vodka to yield one of four BAC levels (0.00%, 0.05%, 0.07%, or 0.09%); however, alcohol was not found to affect risk-taking in this study. The concept of risk compensation is used to assist in the interpretation of the results. Prior to discussion of the methodology and results of the current study, the literature on the Theory of Risk Homeostasis and on the effect of alcohol on industrial tasks is given to show how this study fits into the spectrum of research. Lastly, recommendations are given for various considerations in conducting research on risk-taking and alcohol. / Master of Science / incomplete_metadata

A major design aspect of touch tablet operation is the display/control (D/C) gain. The primary objective of this research was the development and optimization of a variable D/C gain to improve human performance with touch tablets. This variable gain minimizes the speed-accuracy trade-off problem associated with traditional D/C gains. An additional objective.of this research was to determine the effect of tablet size on human performance. Display/control (D/C) gain is defined as the amount of movement which occurs on the display in response to a unit amount of movement of the control. With traditional D/C gains, there is a trade-off between low D/C gain which enables fine positioning, but results in very slow cursor movement, and high D/C gain which produces quick cursor movement but results in poor fine positioning ability. A lead-lag compensator which ameliorates this trade-off problem was developed. A lead-lag compensator is composed of a pure position gain component plus an additional velocity gain component. The results indicate that a lead-lag compensator greatly increased the target acquisition rate relative to a traditional D/C gain system. Percentage error increased with lead-lag compensation relative to an uncompensated system. The overall error rates were very low in all cases, however. Tablet size did not appear to significantly affect performance; performance on the three tablet sizes was generally consistent. / M.S.

User system interface guidelines are emerging as a tool for user interface design. However, guidelines are relatively new, and the effectiveness of guidelines in their present form is still being debated. Some designers of USI tools are attempting to place guidelines online in browsing systems, often as a part of automated USI design tools. This thesis studies the role levels of abstraction has on the detection of USI guidelines violations in user interface evaluation. Studies of online guidance systems, such as help manuals, have yielded mixed results in comparing performance when using online systems versus hardcopy manuals. This thesis also explores the effect which guideline presentation media has upon guidelines usage. / Master of Science

Preferences for four types of hand pruners were solicited from an active elderly population and these preferences were analysed in relation to anthropometric and demographic characteristics of sample members. Participants at senior multipurpose centers included thirty-four females and sixteen males ranging from fifty-two to eighty-three years of age. The subjects were surveyed individually in a single session in which the investigator asked selected demographic questions, measured their grip strength and hand length and recorded their ranking and evaluation of four pruners. The independent variables included, age, sex, hand length, grip strength, dwelling, problems with hands, and experiences with hand pruners. Relationships between sex and hand size, and sex and grip strength were assessed with t-testing. The four pruners were chosen to reflect the following combinations: hook and blade with simple lever, anvil and blade with simple lever, hook and blade with compound lever, and anvil and blade with ratchet mechanism. Other characteristics included handle design and weight. The Friedman ranking test was used to determine the factors which significantly affected pruner preferences. Of the variables measured, sex, hand size, grip strength, and type of residence were associated with pruner preference. Of those groups displaying significant results from the Friedman ranking tests, only the group containing the top third strongest grip strengths showed a rank order with the compound lever pruner higher than the simple lever hook and blade pruner. T-tests showed relationships between sex and hand length, and sex and grip strength. The simple levered anvil and blade pruner placed highest in all significant rankings while the compound and ratchet were placed low in the rankings. The compound pruner did not appeal to many of the participants because of by its heaviness and the design of its handles while the ratchet pruner was resisted because of the multiple squeezes needed for proper use. Recommendations for choosing pruners and other hand tools were made along with suggestions for further investigations of factors affecting preferences for hand tools. / Master of Science

A study was conducted to investigate the effects of certain cinematic choices on people’s ability to judge the posture of the wrist from video images. Deviated wrist postures, which are associated with the performance of many tasks, have been reported to play a role in hand and arm discomfort and in a variety of disorders. The goal of this study was to gain a better understanding of people’s performance in judging wrist posture as well as people’s ability to judge their performance. One objective was to determine the relative performance effects of one still image, two still images, and full-motion images. Other objectives were to determine the effect on performance relative to three different views and ten different wrist positions. It was also of interest to begin to understand how these three independent factors may interact with one another and also how the three dependent variables-accuracy, certainty, and decision time-related to one another. A second experiment also investigated the display effects of a single still image vs. full-motion video. A second factor that was investigated was the performance effects of more complex hand positions (i.e., while holding objects and performing real tasks). In the first Experiment it was found that a view which was normal to the thumb-side of the hand resulted in significantly better performance than a view oblique to the hand. This effect held for each of the Display Methods and for seven of the ten wrist positions. It was hypothesized that this effect may be due to the inherent superiority of one view over another. An alternative possibility is that the thumb-side view offered participants the opportunity to compare what they saw on the screen to their own hands. It was suggested that these alternative possibilities be tested as the results may either support efforts to find “the best view” or to develop ways to provide “comparison postures.” In the first experiment there were significant main and interaction effects for the dependent variable, accuracy. There were also significant main effects found for certainty and decision time, but no interaction effects were found. An interesting finding from the first experiment was that people were generally overly confident of their performance. In most instances, participants’ performances were not related to their perceived performances. For the full-motion images, half of the participants’ perception of their performance was negatively correlated with actual performance. As would be expected, two views were generally found to be better than one view. However, it was also found that a particular single view (thumb-side) resulted in a level of performance that was not significantly different from two-still combinations which did not include the thumb-side view. No significant effects were found for the second experiment and the levels of performance were found to be similar to the first experiment under the oblique view condition. As a background to the experimental investigations, literature pertaining to these four areas was reviewed: The relationship of wrist posture to hand and arm disorders, methods of observing posture, advancements in video technology, and considerations regarding the nature of video as a two-dimensional display format. Also explored were differences in public perception about the task-related “causes” of hand and arm disorders vs. the clinical and observational findings that were reviewed. It was suggested that the ergonomic community bears some responsibility for these differences. Better methods are needed not only to observe human factors, but also to communicate our observations amongst ourselves, to other professionals, and to anyone who could benefit by such knowledge. / Master of Science

No / This four volume set provides the complete proceedings of the 10th International Conference on Human-Computer Interaction held June, 2003 in Crete, Greece. A total of 2,986 individuals from industry, academia, research institutes, and governmental agencies from 59 countries submitted their work for presentation at the conference. The papers address the latest research and development efforts, as well as highlight the human aspects of design and use of computing systems. Those accepted for presentation thoroughly cover the entire field of human-computer interaction, including the cognitive, social, ergonomic, and health aspects of work with computers. The papers also address major advances in knowledge and effective use of computers in a variety of diversified application areas, including offices, financial institutions, manufacturing, electronic publishing, construction, health care, and disabled and elderly people.

Thesis (MComm)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: When considering the attitude of a workforce towards their work and ways of increasing their motivation, attention must be given to their culture. Attitudes within In this study the influence of culture on the implementation of ergonomics was studied with specific reference to the transfer of technology in developing countries. Cultural diversity factors such as language/communication, religious beliefs, anthropometrics, educational background time, ethnicity values, attitude and values was measured using a specially designed questionnaire. It was completed by eighteen managers representing seven large industries in the Mpumalanga province. The cultural factor with the highest significance was 'time'. Others with high significance were educational background, attitude, language/communication and values. Ethnicity values, anthropometrics and religious beliefs were cultural factors which was not considered to be significant, however the population was very small and it is considered that they do contribute towards the implementation of ergonomICS. Training, imported technology and management are external factors, which make a useful and practical contribution to the subject of Ergonomics and the implementation thereof in organizations. If understood, cultural factors provide a much richer environment and different viewpoints, which can increase productivity by the effective use of technology. an organization are due to the attitudes that exist in the culture from which the members of the organization have come. Management practices, therefore, must cope with the attitudes and prejudices of the cultures within the organization. These cultures have been influenced by many factors like religious doctrine and history, not primarily concerned with the efficiency and productivity of the organization. Ergonomics aim at the optimization of the interaction between human and machine and the operating environment. This can provide the information necessary to promote an acceptable and efficient interaction between human-machine and environment in any form of a human-at-work system. In the process of technology transfer from Industrial Developed Countries to Industrial Developing Countries, emphasis is laid on economic progress. Although improvement of the economic situation and the standard of living is important to achieve, neglecting ergonomic considerations is both economically expensive and socially disturbing, thus creating negative effects in the country acquiring the technology. Ergonomics serve as a link between human factor considerations and the transfer of technology. A comprehensive systems model of Ergonomics was used, which indicates the interaction between facets emphasizing information as a core dynamic process, which can be useful to ensure optimality of choices of technology. / AFRIKAANSE OPSOMMING: Wanneer 'n werkerskorps ondersoek word met betrekking tot hul houdings teenoor werk en wyses om hul motivering te verhoog, moet aandag geskenk word aan hul kultuur. Houdings binne 'n organisasie ontstaan uit houdings wat reeds bestaan in die kultuur waaruit lede van die organisasie oorspronklik kom. Bestuurspraktyke moet die houdinge en bevooroordelings van kulture binne die organisasie hanteer. Hierdie kulture is beYnvloed deur vele faktore soos geloofsdoktrines en geskiedenis wat nie primer gerig is op die effektiwiteit en produktiwiteit van die organisasie nie. Ergonomika het ten doel die optimisering van die interaksie tussen mens en masjien en die omgewing van funksionering, wat die nodige inligting kan voorsien wat nodig is om aanvaarbare en effektiewe interaksie te bewerkstellig tussen mens, masjien en die omgewing ten opsige van enige mens-by-sy-werk sisteem. In die proses van tegnologiese oordrag vanaf Industriele Ontwikkelde Lande na Industriele Ontwikkelende Lande, word klem gele op ekonomiese vooruitgang. Alhoewel verbetering van die ekonomiese situasie en 'n verhoging van die standaard van lewe belangrik is om te bereik, sal die verwaardlosing van ergonomiese oorwegings beide ekonomies duur en sosiaal verontrustend wees en gevolglik negatiewe effekte veroorsaak binne die land wat die tegnologie moet verkry. Ergonomika dien as 'n skakel tussen die menslike faktor oorwegings en die oordrag van tegnologie. 'n Omvattende sisteem model van Ergonomika dui op die interaksie tussen belangrike fasette van inligting as 'n dinamiese kern proses wat bruikbaar kan wees by die optimisering van keuses van tegnologie. In hierdie studie word die invloed van kulturele faktore op die implementering van ergonomika bestudeer met spesifieke verwysing na die oordrag van tegnologie. Kulturele diversiteitsfaktore soos taal/kommunikasie, gelowe, antropometrie, opvoedkundige agtergrond, tyd, etniese waardes, houding en waardes is gemeet deur 'n spesiaal ontwerpte vraelys. Dit is voltooi deur agtien bestuurders wat sewe groot industriee in die Mpumalanga provinsie verteenwoordig. Die kulturele faktor wat as die mees beduidend gemeet het is 'tyd'. Ander beduidende faktore is opvoedkundige agtergrond, houdings, taal/kommunikasie en waardes. Nie beduidende faktore naamlik, etnisiteit, antropometrie en gelowe is weI beskou as bydraend in die implementering van ergonomika aangesien die populasie wat gemeet is as relatief klein beskou kan word en moontlik in 'n groter populasie as beduidend kon meet. Opleiding, ingevoerde tegnologie en bestuur is eksterne faktore wat 'n waardevolle en praktiese bydrae maak tot die vakgebied en die implementering van Ergonomika. Kulturele diversiteit voorsien 'n ryk omgewing met verskillende uitgangspunte en indien dit verstaan word kan dit lei tot verhoogde produktiwiteit deur verbeterde gebruik van tegnologie.