Evaluation of proper height for squatting stool

Many jobs and activities in people's daily lives have them in squatting postures. Jobs such as housekeeping, farming and welding require various squatting activities. It is speculated that prolonged squatting without any type of supporting stool would gradually and eventually impose musculoskeletal injuries on workers. This study aims to examine the proper height of the stool according to the position of working materials for the squatting worker. A total of 40 male and female college students and 10 female farmers participated in the experiment to find the proper stool height. Student participants were asked to sit and work in three different positions: floor level of 50 mm; ankle level of 200 mm; and knee level of 400 mm. They were then provided with stools of various heights and asked to maintain a squatting work posture. For each working position, they were asked to write down their thoughts on a preferred stool height. A Likert summated rating method as well as pairwise ranking test was applied to evaluate user preference for provided stools under conditions of different working positions. Under a similar experimental procedure, female farmers were asked to indicate their body part discomfort (BPD) on a body chart before and after performing the work. Statistical analysis showed that comparable results were found from both evaluation measures. When working position is below 50 mm, the proper stool height is 100 or should not be higher than 150 mm. When working position is 200 mm, the proper stool height is 150 mm. When working position is 400 mm, the proper stool height is 200 mm. Thus, it is strongly recommended to use proper height of stools with corresponding working position. Moreover, a wearable chair prototype was designed so that workers in a squatting posture do not have to carry and move the stool from one place to another. This stool should ultimately help to relieve physical stress and hence promote the health of squatting workers. This study sought to evaluate and make suggestions on user preference and BPD of proper stool height, at which work can be done comfortably, according to squatting work position. In short, results showed that proper stool height differed according to working position, even with similar squatting tasks.     

Evaluation of proper height for squatting stool

Many jobs and activities in people's daily lives have them in squatting postures. Jobs such as housekeeping, farming and welding require various squatting activities. It is speculated that prolonged squatting without any type of supporting stool would gradually and eventually impose musculoskeletal injuries on workers. This study aims to examine the proper height of the stool according to the position of working materials for the squatting worker. A total of 40 male and female college students and 10 female farmers participated in the experiment to find the proper stool height. Student participants were asked to sit and work in three different positions: floor level of 50 mm; ankle level of 200 mm; and knee level of 400 mm. They were then provided with stools of various heights and asked to maintain a squatting work posture. For each working position, they were asked to write down their thoughts on a preferred stool height. A Likert summated rating method as well as pairwise ranking test was applied to evaluate user preference for provided stools under conditions of different working positions. Under a similar experimental procedure, female farmers were asked to indicate their body part discomfort (BPD) on a body chart before and after performing the work. Statistical analysis showed that comparable results were found from both evaluation measures. When working position is below 50 mm, the proper stool height is 100 or should not be higher than 150 mm. When working position is 200 mm, the proper stool height is 150 mm. When working position is 400 mm, the proper stool height is 200 mm. Thus, it is strongly recommended to use proper height of stools with corresponding working position. Moreover, a wearable chair prototype was designed so that workers in a squatting posture do not have to carry and move the stool from one place to another. This stool should ultimately help to relieve physical stress and hence promote the health of squatting workers. This study sought to evaluate and make suggestions on user preference and BPD of proper stool height, at which work can be done comfortably, according to squatting work position. In short, results showed that proper stool height differed according to working position, even with similar squatting tasks.     

Effects of arm support on shoulder and arm muscle activity during sedentary work

The aim of this study was to evaluate different arm supports by comparing the activity of shoulder and arm muscles during various work tasks, with and without the lower arm supported. Twelve female subjects, aged between 23 and 37 years, were asked to perform three types of tasks: typing, simulated assembly work (in two different positions), and pipetting. The supports used were: fixed arm support (FIX), horizontal movable arm support (HOR), and spring-loaded arm support (SLA). During the experiments, the electromyograms (EMG) of four muscles were simultaneously recorded: m. deltoideus anterior and lateralis, m. trapezius pars descendens and m. extensor carpi radialis brevis. Normalization was made against maximum isometric contraction. The mean values of the normalized EMG levels showed a reduced EMG level of the shoulder muscles when using arm supports in all the tasks, and for all muscles but the wrist extensor, compared to the EMG levels without arm supports. The horizontal movable support was more effective in reducing the EMG levels of the shoulder muscles than other arm supports, in tasks at table height. Thus, it is possible to reduce muscle activity of the shoulder region by using arm supports. Further research is needed to make biomechanical calculations to compare the EMG level of these muscles using suspension and the effects of inclination of work task.     

Trends and issues of regulative support use during inquiry learning: Patterns from three studies

This paper looks across three experimental studies that examined supports designed to assist high-school students (age 15–19) with cognitive regulation of their physics inquiry learning efforts in a technology-enhanced learning environment called Co-Lab. Cognitive regulation involves the recursive processes of planning, monitoring, and evaluation during learning, and is generally thought to enhance learning gains for students. The research synthesis described in this paper examined the usage effects of a support tool called the process coordinator (PC) on learning outcomes. This tool incorporated goal-lists, hints, prompts, cues, and templates to support the cognitive regulation skills of students during a fluid dynamics task. Students were asked to produce two learning outcomes of their investigations: system dynamics models and lab reports. Results from the three studies indicated trends in frequent use of the PC for planning activities, but low usage for monitoring and evaluation. Correlational analysis revealed two trends with regard to how these regulative activities impacted learning outcomes. First, consistent positive correlations were apparent between regulative activities and lab report scores of students and second, consistent negative correlations between the use of supports and model quality scores. Trends with regard to how task complexity, time, and student prior experience impacted these findings are also presented with suggestions for future research.     

User Preference for a Control-Based Reduced Processing Decision Support Interface

This study examined trainee crime-scene investigators' preference for, and accuracy in using, four different computer-based decision support interface designs, each of which incorporated a different reduced processing information acquisition strategy. The interfaces differed on the basis of the number of options that could be considered simultaneously and the level of control that could be exercised over the number and sequence in which feature values were accessed. Forty trainee investigators completed six decision scenarios in which they were asked to acquire information and formulate a decision by selecting one of three options. The study comprised two phases, the first of which involved familiarizing participants with each of the four interface designs and collecting performance and subjective data. The second phase involved trainees selecting one of the four interfaces to engage in a fifth and sixth decision scenario involving high or low levels of time-pressure. The results indicated that the “all options, full control” interface was the preferred option in the low time-pressure condition. Although the strategy remained the most frequently selected in the high time-pressure condition, this preference was not significant. It was concluded that the perceptions of difficulty and the degree of user control over information acquisition were more important than perceived efficiency in the selection of computer-based interface designs. The outcomes have implications for the design of decision support systems.     

城市景观设计之环保公共厕所

环保型厕所必须是通过一定的现代科技手段的应用,能够有利于改变或减少传统公厕所排放物对周围环境的污染;能够有利于改变或减少传统公厕对清理、消除排放物而必须付出的对自然生态物质的消耗的;能够对排放物进行回收利用处理的生态化;能够使设计具有人性化,在外型设计上注重与周围景观的谐调,成为景观中有机的组成部分;能够以厕养厕。     

Computer mouse or Trackpoint—effects on muscular load and operator experience

The aim of the study was to evaluate four different modes of human-computer interaction. The modes were: use of the keyboard alone as input device, use of keyboard and mouse, use of keyboard and mouse with a three-dimensional arm support, and use of a keyboard with a Trackpoint device in its centre. Ten women and 10 men volunteered to participate. Questions asked were whether working in the different modes influenced shoulder and forearm muscular load differently during word processing, and how much strain on the neck, shoulder and arms subjects perceived in the different modes.

Muscular load was studied with electromyography in three shoulder muscles and three forearm muscles. The subjects also rated the different modes in one questionnaire concerning perceived strain and in one concerning preference for any of the modes tested.

Intra-individual analysis for each muscle and mode showed two possible ways of decreasing the strain from computer mouse work on the shoulder muscles—either to use Trackpoint or to use the mouse combined with the movable arm support. However, both of these computer-interaction modes increased the muscular load in the hand and forearm.     

The use of attention resources in navigation versus search

Personal information management research has consistently shown navigation preference over search. One possible explanation for this is that search requires more cognitive attention than navigation. We tested this hypothesis using the dual-task paradigm. We read a list of words to each of our 62 participants, asked them to navigate or search to a target file, and then compared the number of words recalled in each condition. Participants remembered significantly more words when retrieving by navigation than by search. The fact that they performed better at the secondary task when navigating indicates that it required less cognitive attention than search. Our results also cast doubt on the assumption that search is more efficient and easier to use than navigation: Search took nearly three times longer than navigation, was more vulnerable to mistakes and retrieval failures and was perceived as more difficult on a subjective evaluation. Our results also support the folk belief that women are better than men and that younger people are better than older ones, at multitasking.     

Misery rarely gets company: The influence of emotional bandwidth on supportive communication on Facebook

This study introduces the concept of emotional bandwidth to describe a communicator’s ability to use technological features to disclose personal affect online. Strategic use of emotional bandwidth was expected to correspond with interpersonal rewards, specifically the willingness of others to provide social support. Participants (N = 84) viewed hypothetical Facebook profiles that contained manipulated levels of emotional bandwidth and were asked how much support they would provide to the person in the profile. Participants who viewed profiles portraying high emotional bandwidth were less willing to provide social support; however, this finding was qualified by personal qualities. Females, people who perceived a sense of community, and people who had a preference for online social interaction indicated a greater willingness to provide support in the high emotional bandwidth condition. Implications for designing affective affordances in technologies and their psychological effects are discussed.     

An ergonomics approach to refrigerator design for the elderly person

The objective was to determine a set of refrigerator design guidelines for independent living elderly women. The study was conducted with a refrigerator mockup with interchangeable internal features. Twelve elderly women participated, both in a standing and seated (wheelchair) position. The participants were videotaped as they simulated use of shelves and drawer, and they rated these components and their positions for acceptability of reach, visibility of contents, and personal preference. Participants then used a variety of mockup items to configure the refrigerator to their own preferred design. These were then analysed and synthesised into three 'consensus' designs combining the features of most of the others.     

Optimally small operator supports for fully parallel thinningalgorithms

Requirements for the support size and shape are investigated for the class of all adequate fully parallel thinning operators. Eleven pixel supports are shown to be the smallest possible supports, and the possible positions of the support pixels are shown to be well constrained. Constraints on support positions are demonstrated for operators with supports that are larger than optimal, and a sufficient test for connectivity preservation is reviewed. These results allow algorithm designers looking for small support operators to focus on a relatively small set of acceptable supports     

Social interaction in online support groups: Preference for online social interaction over offline social interaction

The purpose of the current study was to identify potential factors leading to preference for social interaction in online support groups (OSGs) over offline interaction. By identifying such factors, the current study advances understanding of the way patients use the Internet as a supportive resource and integrate support from offline and online relationships. An online survey was conducted with current users of health-related OSGs (N = 158). Findings show that those who were dissatisfied with the support they received from their current offline contacts were more likely to prefer social interaction in OSGs. Such a preference was prominent among those who built deeper social relationships in OSGs. Results suggest that some people develop a preference for social interaction in OSGs over offline interaction and use computer-mediated relationships as a possible alternative to offline support networks. Healthcare professionals and users as well as designers of OSGs must acknowledge the limits of online support and caution against the possibility of developing excessive reliance on online support resources.     

Incidental memory and navigation in panoramic virtual reality for electronic commerce

Recently much effort has been dedicated to designing and implementing World Wide Web sites for virtual shopping and e-commerce. Despite this effort, relatively little empirical work has been done to determine the effectiveness with which different site designs sell products. We report three experiments in which participants were asked to search for products in various experimental e-commerce sites. Across the experiments participants were asked to search in either QTVR (QuickTime Virtual Reality), hypertext, or pictorially rich hypertext environments; they were then tested for their ability to recall the products seen and to recognize product locations. The experiments demonstrated that when using QTVR (Experiments 1, 2, and 3) or pictorial environments (Experiment 2), participants retained more information about products that were incidental to their goals. In two of the experiments it was shown that participants navigated more efficiently when using a QTVR environment. The costs and benefits of using 3D virtual environments for on-line shops are discussed. Actual or potential applications of this research include support for the development of e-commerce design guidelines.     

Interactive visual supports for children with autism

Interventions to support children with autism often include the use of visual supports, which are cognitive tools to enable learning and the production of language. Although visual supports are effective in helping to diminish many of the challenges of autism, they are difficult and time-consuming to create, distribute, and use. In this paper, we present the results of a qualitative study focused on uncovering design guidelines for interactive visual supports that would address the many challenges inherent to current tools and practices. We present three prototype systems that address these design challenges with the use of large group displays, mobile personal devices, and personal recording technologies. We also describe the interventions associated with these prototypes along with the results from two focus group discussions around the interventions. We present further design guidance for visual supports and discuss tensions inherent to their design.     

Explaining machine learning models in sales predictions

A complexity of business dynamics often forces decision-makers to make decisions based on subjective mental models, reflecting their experience. However, research has shown that companies perform better when they apply data-driven decision-making. This creates an incentive to introduce intelligent, data-based decision models, which are comprehensive and support the interactive evaluation of decision options necessary for the business environment.Recently, a new general explanation methodology has been proposed, which supports the explanation of state-of-the-art black-box prediction models. Uniform explanations are generated on the level of model/individual instance and support what-if analysis. We present a novel use of this methodology inside an intelligent system in a real-world case of business-to-business (B2B) sales forecasting, a complex task frequently done judgmentally. Users can validate their assumptions with the presented explanations and test their hypotheses using the presented what-if parallel graph representation. The results demonstrate effectiveness and usability of the methodology. A significant advantage of the presented method is the possibility to evaluate seller’s actions and to outline general recommendations in sales strategy.This flexibility of the approach and easy-to-follow explanations are suitable for many different applications. Our well-documented real-world case shows how to solve a decision support problem, namely that the best performing black-box models are inaccessible to human interaction and analysis. This could extend the use of the intelligent systems to areas where they were so far neglected due to their insistence on comprehensible models. A separation of the machine learning model selection from model explanation is another significant benefit for expert and intelligent systems. Explanations unconnected to a particular prediction model positively influence acceptance of new and complex models in the business environment through their easy assessment and switching.     

Perceptions of driver distraction by cellular phone users and nonusers

The present study examined the perceptions of cellular phone users and nonusers on issues relating to vehicle control and driver distraction. Participants were asked if they own a cellular phone; if so, how much they use it; and their beliefs regarding cellular phone use while driving, including actions involving the use of cellular phones which could potentially cause vehicular accidents and the need for laws. A total of 330 individuals participated; 72% owned a cellular phone. The results indicate that nonusers of cellular phones believed more strongly than users that cellular phone use while driving negatively affects driving performance and that talking on the cellular phone could potentially cause an accident, and they also had a greater preference for new laws limiting such acts. Cellular phone users, more than nonusers, preferred no laws limiting cellular phone use and believed more strongly that other people driving while using a cellular phone were more dangerous than themselves doing the same. Implications of these results are discussed. Actual or potential applications of this research include interventions that limit driver distractibility.     

Executable specifications with data-flow diagrams

Specifications of information systems applications are often based on the use of entity-relationship (ER) and data-flow diagrams (DFD), which cover, respectively, the conceptual modelling of data and funtions. This paper introduces VLP: an executable visual language for formal specifications and prototyping which integrates ER and DFD diagrams in a semantically rigorous and clear way. Unlike existing commercial products (so-called CASE tools), which can support good-quality documentation, simple forms of consistency checking and bookkeeping, VLP also supports executable specifications, which provide a prototype of the desired application. After reviewing the principles of VLP, the paper outlines the structure of the ECASET environment in which VLP is embedded. In particular, it shows how the environment supports the stepwise derivation of specifications, from informal to formal, and how it supports specification-in-the-large.     

Reader preference for report typefaces

A postal survey of typeface preference is described. The survey was designed to help in the choice of typeface to be used for the internal technical Reports produced by the Post Office Research Department. Type setting for these Reports is carried out using an IBM Selectric Composer for which seven typefaces suitable for reports are available. One hundred and twenty-five people who regularly receive copies of these Reports and 57 Trainee Technicians (Apprentices) were asked to arrange these seven typefaces in order of preference and record this ranking on a response sheet. About 85% of both groups returned response sheets for statistical analysis. The results showed a significant preference for three of the typefaces: Press Roman, Theme and Univers. Of these, Press Roman is used for the text of Research Department Reports and Univers is used on diagrams and tables.     

Informal learning with PDAs and smartphones

Abstract There has been increasing interest in informal learning in recent years alongside interest in how such learning can be supported by technology. However, relatively little is known about the extent to which adults make use of their own mobile devices to support informal learning. In this study, a survey was used to investigate whether, and to what extent, experienced users of mobile devices use their mobile devices to support intentional informal learning. If so, do they make use of mobile device connectivity to support opportunistic informal learning and does such connectivity support or encourage collaborative informal learning? Experienced mobile device users were recruited from web forums and business, and asked whether they used their devices to support informal learning. A pattern of learning uses emerged, some of which deployed the mobile device capabilities relatively unchanged, others triggered adaptations to typical learning activities to provide a better fit to the needs of the learner. These informal learning activities provided the basis for the design of a flexible mobile learning framework that can be extended to support developments in mobile technology, and increasing use of Web 2.0 technologies by informal learners.     

Impact of observers' experience and training on reliability of observations for a manual handling task

Observation reliability (agreement percentage and kappa coefficients) for six experienced ergonomists and six untrained participants was computed. Participants were first tested after a training session and 1 week later after an additional practice session. Two formats were used: free practice and directed exercise. Reliability was tested for 17 variables and 20 sequences using photographic and video supports. The participants were asked to indicate whether they were confident about their answer, to rate this confidence on a scale of 1 to 10, and when the confidence rating was below 8, to provide a reason for this. Experience and additional practices had no clear impact on reliability, which was excellent overall. The main reason given was that the event to be observed took place at the borderline between two classes. The observers' rating on the scale appeared to be tied to the subsequent reliability computed. The use of a confidence scale appeared to be a useful tool for forecasting observation problems.