Ergonomic design and evaluation of new surgical scissors

The purpose of this study is to design a new surgical scissors handle and determine its effectiveness with various usability indices. A new scissors handle was designed that retains the professional grip but has the shapes of the eye rings modified to fit the thumb and ring finger and finger rests for the index and little finger. The newly designed scissors and traditional scissors were compared by electromyography, subjective evaluation and task performance in experiments using cutting and peeling tasks. The newly designed scissors reduced muscle load in both hand during cutting by the closing action, and reduced the muscle load in the left hand during peeling by the opening action through active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load. The newly designed scissors used in this study demonstrated high usability.

Practitioner Summary: A new scissors handle was designed that has the eye rings modified to fit the thumb and ring finger. The newly designed scissors reduced muscle load and enabled active use of the right hand. In evaluation by surgeons, task performance improved in addition to the decrease in muscle load.     

Ergonomic assessment of handle design by means of electromyography and subjective rating

Stress and strain during manual tool handling not only depend on factors such as weight to be handled, but are also determined by the design of the man-machine interface. In this study, three different handles of electric hedge-clippers were analysed; the results of a comparative investigation into the physiological cost demanded by the use of the different handles are discussed. Muscular strain was measured via surface electromyography in laboratory experiments with nine male subjects. The results showed significant differences in physiological cost depending on both work height and the handles' shape. Systematic differences in muscular strain between the utilized tools were found, despite the fact that all clippers were compensated with respect to weight and location of the centre of gravity. One of the handle designs enabled working under varying conditions (work height and direction) at a reduced level of muscular strain of the right arm. Results from the physiological evaluation were partly supported by the working persons' own subjective experience. The results of this investigation show that further ergonomic tool and handle design is necessary.     

Ergonomic redesign and evaluation of a clamping tool handle

The handle of a commercial bar clamp was redesigned using ergonomic principles and then compared with an original clamp. Ten male and ten female students participated in simulated clamping tasks under various conditions, including different clamping heights, clamping methods, and handle-gripping methods, with respect to the dependent variables of clamping and handle-squeezing forces. The results showed that the redesigned clamp produced larger clamping force with lower handle-squeezing forces than the original clamp. As expected, males exerted more force than females in both clamping and squeezing forces. A pistol grip method was superior to an upside-down handle-gripping method. Two-handed operation was recommended for this type of clamp by simultaneously pulling the trigger and sliding the bar in order to initially tighten around objects. This study shows that the application of ergonomic guidelines increases the efficiency and usability of manual handtools.     

Ergonomic design visualization mapping- developing an assistive model for design activities

Ergonomic models and techniques are a fundamental issue in the design of comfortable and safe products and spaces. User studies, related to visualization tools are current issues in the ergonomics and design visualization literature. But researchers have begun to discover that user study is rarely straightforward, especially when drawing visualization data from interdisciplinary sources. The availability of a plethora of visualization techniques can make it difficult to determine the most appropriate technique to convey maximum possible understanding.The RT-MHV (“Real-time”– “Motion history volumes”) 3D computerized assessment model, developed by the authors, demonstrates a local risk evaluation of work-related musculoskeletal disorders (WMSDs), based on real-time and on motion history volumes. With the model, the visual display of the WMSD risk level for each body segment is defined by color-coding at points surrounding an avatar's segment, representing an actual user. The values associated with areas with an increased risk of WMSDs can be identified and iterated quickly, so as to determine the “optimal posture”. Designers can share this knowledge by recording the user's postural interactions, defined through the mapping of geometric comfort data and WMSD risk level categories.The challenge in the development process was to overcome existing “gaps” between ergonomics data and designer requirements. Further research on the RT-MHV model is recommended, principally for developing stand-alone CAD software. An aggregated statistical information database and complete body joints visualizations will be computerized in due course. 2D tabulation and statistical information relating to body joints will be made available on demand.     

Effect of handle design and target location on insertion and aim with a laparoscopic surgical tool

Two laparoscopic tools, a scissor-type grasper and an ergonomically designed grasper, were compared in terms of operation efficiency and physical workload while inserting into a simulated abdomen and aiming five cross-shaped targets. Thirty right-handed novice participants performed the tasks with five tool-grasping hand postures at two computer monitor angles that simulated reaching an organ during laparoscopic surgery. When comparing the two free style hand postures used, there was a significant improvement in operation efficiency. This demonstrated that the participants quickly became familiar with the Intuitool by finding new hand postures that will significantly help them reach the target faster and more accurately. The 45( composite function) monitor angle showed the worst accuracy and deviation, the 0( composite function) monitor angle showed the best accuracy and smallest deviation with the upper target. Thus it is recommended that the camera trocar be placed directly above the organ of interest, and the part of the organ to be reached should be displayed slightly above the center of the feedback monitor. For physical workload, the method of gripping the tools was the most important factor. The scissors-type tool caused the largest wrist flexion, in contrast both free styles hand postures with the Intuitool showed the least wrist flexion.     

An interdisciplinary heuristic evaluation method for universal building design

This study highlights how heuristic evaluation as a usability evaluation method can feed into current building design practice to conform to universal design principles. It provides a definition of universal usability that is applicable to an architectural design context. It takes the seven universal design principles as a set of heuristics and applies an iterative sequence of heuristic evaluation in a shopping mall, aiming to achieve a cost-effective evaluation process. The evaluation was composed of three consecutive sessions. First, five evaluators from different professions were interviewed regarding the construction drawings in terms of universal design principles. Then, each evaluator was asked to perform the predefined task scenarios. In subsequent interviews, the evaluators were asked to re-analyze the construction drawings. The results showed that heuristic evaluation could successfully integrate universal usability into current building design practice in two ways: (i) it promoted an iterative evaluation process combined with multi-sessions rather than relying on one evaluator and on one evaluation session to find the maximum number of usability problems, and (ii) it highlighted the necessity of an interdisciplinary ad hoc committee regarding the heuristic abilities of each profession. A multi-session and interdisciplinary heuristic evaluation method can save both the project budget and the required time, while ensuring a reduced error rate for the universal usage of the built environments.     

Product design enhancement using apparent usability and affective quality

In this study, apparent usability and affective quality were integrated in a design framework called the Usability Perception and Emotion Enhancement Model (UPEEM). The UPEEM was validated using structural equation modeling (SEM). The methodology consists of four phases namely product selection, attribute identification, design alternative generation, and design alternative evaluation. The first stage involved the selection of a product that highly involves the consumer. In the attribute identification stage, design elements of the product were identified. The possible values of these elements were also determined for use in the experimentation process. Design of experiments was used to identify how the attributes will be varied in the design alternative stage and which of the attributes significantly contribute to affective quality, apparent usability, and desirability in the design evaluation stage. Results suggest that product attributes related to form are relevant in eliciting intense affect and perception of usability in mobile phones especially those directly related to functionality and aesthetics. This study considered only four product attributes among so many due to the constraints of the research design employed. Attributes related to aesthetic perception of a product enhance apparent usability such as those related to dimensional ratios.     

Iterative process of design and evaluation of icons for interactive TV menu

This paper shows an iterative process of design and evaluation of icons for future interactive TV services. In doing the RNRT (French National Network of Research in Telecommunications) iTV project, we tried to generate icons easy to identify, associate and memorise for 32 categories and services of our iTV system.

Through an iterative process, the Multiple Index Approach was applied until an acceptable icon set was achieved. In addition to existing evaluation criteria such as the intuitiveness, associativeness, preference and suitability with subjective certainty of users, we emphasised the importance of the learnability measured by recall tests.

As a conclusion, we propose a methodology of icon design and evaluation for information appliances that integrate unfamiliar features with common users.     

Iterative process of design and evaluation of icons for interactive TV menu

This paper shows an iterative process of design and evaluation of icons for future interactive TV services. In doing the RNRT (French National Network of Research in Telecommunications) iTV project, we tried to generate icons easy to identify, associate and memorise for 32 categories and services of our iTV system.

Through an iterative process, the Multiple Index Approach was applied until an acceptable icon set was achieved. In addition to existing evaluation criteria such as the intuitiveness, associativeness, preference and suitability with subjective certainty of users, we emphasised the importance of the learnability measured by recall tests.

As a conclusion, we propose a methodology of icon design and evaluation for information appliances that integrate unfamiliar features with common users.     

Hand tool handle size and shape determination based on hand measurements using a contour gauge

The purpose of this study is to provide a novel approach to tool handle design and development based on measurements of hand shape using a contour gauge. In general, traditional design techniques, designing based on anthropometric data, and derived mathematical models do not incorporate enough subject data to design a customized product. First, anthropometric measurements on the right hand of 60 participants were collected with a contour gauge to manufacture matching handles. A curved handle fitting the human hand was constructed with common computer‐aided design software, and cylindrical handles and elliptical handles were added for comparison. All of the handles were used to record the participants' grip force to evaluate the operating efficiency of the handles. Finally, the participants completed a comfort‐rating questionnaire. The results show that contours based on the hand provided the highest operating performance and the best overall comfort‐rating compared to cylindrical handles and elliptical cylindrical handles. The newly developed handles in the grip force tasks have the highest push performance and the best comfort ratings compared to traditional cylindrical and elliptical handles. The developed handles could provide the hand tool industry information on developing and manufacturing many other similar handle designs (such as those for saws and electric screwdrivers).     

An ergonomic design and performance evaluation of handy scanners by males

This paper describes the results of an investigation of the difference in performance, posture used, strain on forearm musculature, and subjective ratings of three handy scanners (models A, B and C). Both models A and B were scanners on the market. Model C was developed for validation. The gripping posture of the three models is distinct both in the anatomical and functional sense. Work with model A requires a thumb-forefinger side grip which induces an ulnar deviation angle; work with model B requires a thumb-finger grip; work with model C requires a thumb-finger-palmar grip. Performance evaluation of scanner models A, B and C on different scanning tasks (with and without stitch) using different resolution modes (100 and 400 dpi), indicated that using the proposed model C resulted in a 13% higher success rate, a 14% shorter completion time, the smallest self-selected working area, least strain on the forearm muscles, and highest subjective ratings among the three. Model C appeared to provide the greatest opportunity for delicate adjustments of posture in response to the activity of the skin receptors, justifying the ergonomic input into the design.     

基于网络的产品可用性评价系统的设计与实现

随着科学技术的不断发展和产品智能化水平的不断提高,产品的可用性已是消费者决定是否购买产品的主要因素,因此,提高产品的可用性已成为提高产品竞争力的核心。如何保证设计的产品既符合用户的需求又方便易用,即可用性问题,成为必须不断深入研究的问题。论文将目前国内外企业针对界面设计的可用性理论引入到工业产品设计中,从产品设计的角度对工业产品的可用性评估原则、流程和方法进行了探讨性研究。     

产品设计中的易用性研究

易用性以人机工程学和心理学为理论基础,强调用户在产品使用过程中的心理变化。它逐渐成为评价产品设计好坏的标准,是目前产品设计的新趋势,新方向。     

Ergonomic evaluation of an alternative tool for cake decorating

AimCake decorating involves several hand intensive steps with high grip force during the application of icing. The purpose of this laboratory study was to evaluate forearm muscle activity, discomfort, productivity, and usability of an alternative tool for cake decorating compared to decorating with the traditional piping bag.MethodsParticipants (n = 17) performed 2 h of cake decorating tasks using the two tools. Subjective hand and arm fatigue, usability, upper extremity posture, and muscle activity from three forearm muscles were assessed for each tool. Outcome measures were evaluated using the Wilcoxon Signed Rank test and the paired t-test.ResultsLess fatigue was reported in the dominant hand (p = 0.001), forearm (p = 0.003) and shoulder (p = 0.02) for the alternative tool when compared to the piping bag. Average median (APDF 50%) and peak (APDF 90%) muscle activity was significantly less for the alternative tool across all three forearm muscles. The alternative tool significantly reduced grip force, an important risk factor for distal upper extremity pain and disorders. Participants rated usability of the alternative tool superior for refill and comfort but the traditional method was rated better for accuracy, stability, positioning and control.ConclusionsThe alternative tool was associated with less dominant arm fatigue, muscle activity, and grip force when compared with the piping bag. However, the alternative tool did not receive the best overall usability rating due to problems with accuracy and overflow, especially with smaller decorating tips. Recommendations were made for addressing these problems with the alternative tool.     

Cognitive evaluation for conceptual design: cognitive role of a 3D sculpture tool in the design thinking process

ABSTRACT

This study focuses on the decisive role played by the digital design environment in the cognitive design process and design thinking. To analyse the cognitive role of digital design tools, we carried out a protocol analysis of conventional design sketching and a 3D sculpture tool. Cognitive evaluation was a differentiating factor when considering the contextual role of the 3D sculpture tool in subsequent evaluations, non-sequential evaluations for conversion, and passive approaches within the design process. Cognitive evaluation played the following roles: validation, extension, navigation, exploration, and confirmation. The navigation, exploration, and extension roles played by non-sequential evaluation were mainly related to inductive design thinking. Finally, the types of cognitive evaluation and their roles when using the 3D sculpture tool were different, according to the design thinking type. This study explored the multidimensional roles of cognitive evaluation using a 3D sculpture tool and its relationship with design thinking types.     

Safer chairs for elderly patients: design evaluation using electromyography and force measurement

A vast majority of patient fall events in hospitals involve the elderly. In inpatient care settings, despite the risk of fall, patients are encouraged to leave their bed, move around their room, and sit on their chair to progress in their healing. Despite the vital role of patient chair design in improving recovery, few studies have examined the ergonomic requirements of safe patient chairs. This study examined the impact of manipulating horizontal and vertical positions of armrests in a test chair on required physical effort during Stand-to-Sit-to-Stand (St-Si-St) transitions among 15 elderly women. Physical effort was measured using: (1) surface electromyography (sEMG); (2) force measurement by load cells; (3) video recording. Findings showed non-linear patterns of change in required physical effort due to changes in armrests’ height and distance. It was also found that minimum effort is associated with armrests higher and farther apart than those in typical patient chairs.

Practitioner Summary: Safe chairs are essential for inpatient recovery, yet their ergonomic features are not investigated. Impact of changes in chair armrests on required physical effort was examined using electromyography, force measurement and video recording. Armrests higher and farther apart than those in typical patient chairs may be safer for elderly patients.     

The influence of rice plow handle design and whole-body posture on grip force and upper-extremity muscle activation

A previous job screening study revealed ergonomics risk factors in rice field plowing. This work motivated the present experimental investigation of the influence of plow handle design and farmer whole-body posture on grip force and arm muscle activity. A total of 24 experienced farmers performed a simulated plowing task, including walking on even and uneven ground while rolling a tiller equipped with conventional horizontal and proposed vertical handles. Results revealed the proposed handles, designed to promote neutral wrist posture, to increase upper-arm muscle use between 47% and 70% across ground types, as compared with conventional handles. The ratio of grip force to forearm muscle activity (or efficiency in muscle use) increased from 1.85 when using conventional handles on uneven ground to 2.16 when using the proposed handles with symmetrical body posture on even ground. However, participants perceived higher discomfort when using the proposed handles, as they were accustomed to the conventional design.     

基于界面设计模式的界面开发工具综述*

良设计的界面可为用户提供方便易用的服务,增强应用在市场上的竞争力。使用可复用的界面设计模式,旨在提高设计的可用性和效率。界面开发的复杂性需要有工具支持。针对现有基于模式的界面开发工具,本文根据它们对不同开发阶段的支持进行分类,然后对各类工具进行探讨,从形式、功能、可用性等特征展开分析和比较,最后,本文讨论了目前工具存在的不足及未来的研究方向。     

Muscle fatigue based evaluation of bicycle design

Bicycling posture leads to considerable discomfort and a variety of chronic injuries. This necessitates a proper bicycle design to avoid injuries and thereby enhance rider comfort. The objective of this study was to investigate the muscle activity during cycling on three different bicycle designs, i.e., rigid frame (RF), suspension (SU) and sports (SP) using surface electromyography (sEMG). Twelve male volunteers participated in this study. sEMG signals were acquired bilaterally from extensor carpi radialis (ECR), trapezius medial (TM), latissimus dorsi medial (LDM) and erector spinae (ES), during 30 min of cycling on each bicycle and after cycling. Time domain (RMS) and frequency domain (MPF) parameters were extracted from acquired sEMG signals. From the sEMG study, it was found that the fatigue in right LDM and ES were significantly (p < 0.05) higher in SP bicycle. This was corroborated by a psychophysical assessment based on RBG pain scale. The study also showed that there was a significantly lesser fatigue with the SU bicycle than the RF and SP bicycles.