• Journal of the Ergonomics Society of Korea
• /
• v.36 no.1
• /
• pp.9-21
• /
• 2017

Objective: The objective of this study is to understand the effect of angle and curvature of push-return switches, which are external factors in the operation environment inside the cars, on the feel of operation and to propose optimum alternatives. Background: Customers' needs for products are changing from functional and performance aspects to customer-led type where customers can reflect on their needs on the products. The operation inside cars is executed by HMI. The push-return switch is utilized as the most intuitive mode of HMI; therefore, this push-return switch, which is widely used, has to be developed by assessing the preference and satisfaction of the customer. Method: The angle and curvatures, which are external factors that affect the feel of operation, are drawn through surveying the preceding research literatures. The stages to construct alternatives in experiments are as follows: (1) the tactile switch is replaced after dismantling the switch assembly to evaluate the internal characteristics proposed by preceding researches, (2) a drawing is prepared by using a design software, is printed using 3D printer, and then it is attached on the switch assembly, and (3) evaluation for satisfaction of operation is carried out by using a driving simulator. Results: Both the angle and curvature that are external factors of switch significantly affect the feel of operation. However, interaction between the two factors is found insignificant. Therefore, an optimum alternative is proposed considering the experimental outcomes. Conclusion: This study evaluates the satisfaction in operation that affects the feel of operation environment inside the cars. Based on the study results, a guideline for switch design in the center fascia is proposed. Application: This study is expected to be used as basic data for designing automotive switches, as well as switches in the industries similar with the operation environments of cars.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.143-143
• /
• 2017

산업이 고도화됨에 따라 자동화 기계 및 로봇에 의해 대량 생산 되는 품목과 달리, 작업 절차의 비정형성, 비연속성 등으로 인해 여전히 농업에 많은 인력이 투입되고 있다. 국제노동기구에 따르면, 세계 인력의 절반이 농업 인력에 해당하고 작업 중 부상이나 사망 등으로 인해 가장 위험한 직업군 중 하나에 해당하는 것으로 나타났다. 시설 재배 농업의 경우, 노동집약적인 온실 내 작업 특성상 잘못된 자세로 작업하거나 지나친 작업량 등으로 인해 작업자에게 근골격계 질환이 발생할 수 있다. 근골격계 질환으로 인해 작업효율이 감소하거나 생산비용의 증가로 이어질 수 있으며, 농가 수익에 손실이 발생할 수 있다. 이에 본 연구에서는 현행 시설 재배 농업에서 사용되는 레일 전동 작업차를 이용하여 작업자가 토마토를 수확할 때의 신체에 대한 농작업의 부하를 평가하고자 하였다. 작업차를 이용한 주요 작업 절차는 작물로부터 과실 수확, 과실 상자에 과실 투입, 빈 과실 상자와 가득 찬 과실 상자의 교대, 작업차 위의 과실 상자를 운반용 파레트에 하역하는 순서로 이루어지는 것을 확인하였다. 비디오장비로 촬영된 일련의 농작업 과정을 OWAS, RULA, REBA와 같은 체크리스트형 인간공학적 작업 부하 평가 도구를 이용하여 평가한 결과, 기존 레일 전동 작업차를 이용한 농작업의 근골격계 질환 유발 가능성을 확인하였다. 동작별 위험성을 토대로 근골격계 질환 유발 가능성이 높아 개선이 필요한 농작업 동작을 선정하였다. 선정된 동작은 실험실 내 환경에서 피실험자를 통한 모의 동작의 생체 신호 계측을 통해 신체 부하 정도를 정량적으로 측정할 수 있으며, 보조가 필요한 신체 부위를 특정하거나 안전성 확보가 필요한 동작에 대한 증거가 될 수 있다. 본 연구를 통해 향후 토마토 온실 내 신선도 유지를 위한 레일 전동 작업차의 개발에 작업자의 안전과 효율성 향상을 위한 인간공학적 설계를 적용할 수 있을 것으로 기대한다.

• Journal of Fashion Business
• /
• v.20 no.3
• /
• pp.17-29
• /
• 2016

To develop baseball catcher leg guards, 3-dimensional (3D) methodologies, which are 3D human body data, reverse engineering, modeling, and printing, optimized guard design for representative positions. Optimization was based on analysis of 3D body surface data and subjective evaluation using 3D printing products. Reverse engineering was used for analysis and modeling based on data in three postures: standing, $90^{\circ}$ knee flexion, and $120^{\circ}$ knee flexion. During knee flexion, vertical skin length increased, with the thigh and knee larger in anterior area compared to the horizontal dimension. Moreover, $120^{\circ}$ knee flexion posture had a high radius of curvature in knee movement. Therefore, guard designs were based on increasing rates of skin deformation and numerical values of radius of curvature. Guards were designed with 3-part zoning at the thigh, knee, and shin. Guards 1 and 2 had thigh and knee boundaries allowing vertical skin length deformation because the shape of thigh and knee significantly affects to its performance. Guard 2 was designed with a narrower thigh and wider knee area than guard 1. The guards were manufactured as full-scale products on a 3D printer. Both guards fit better in sitting than standing position, and guard 2 received better evaluations than guard 1. Additional modifications were made and an optimized version (guard 3) was tested. Guard 3 showed the best fit. A design approach based on 3D data effectively determines best fitting leg guards, and 3D printing technology can customize guard design through immediate feedback from a customer.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.30 no.7 s.155
• /
• pp.1090-1102
• /
• 2006

The purpose of this study is to develop an improved work clothing which is much safe, comfortable, mobility and convenient than what workers currently wear at construction site. The investigation has been conducted to evaluate current work clothing to grasp any problems, discomforts and damages related to the work clothing. For the best and accurate data, hands-on investigation and a short-interview have been performed at the construction site as well as formulating a questionnaire. The questionnaires was answered by 425 workers and safety manager of 13 different construction site. The result of the questionnaire enables us to design a sample work clothing, many pa π s such as material, pattern and design have been improved. To improve the amenity of heat, the surface of a material was used by $Aerocool^{\circledR}$ fiber which contains inside dryness function. In order to absorb perspiration on the back the armpits, mesh martial that is mixture of $Coolever^{TM}$ fiber and $Mirawave^{TM}$ fiber was used to absorb perspiration in an effective manner. And a sleeve's bottom part and trousers' bottom part's cover method have been changed. Sample work clothing was shorten at the side of upper garment up to 2cm and lengthen the length of the back by 3cm. To reduce the tightness around armpit more room was given in that area. Darts were added to the elbow, the hip, and the knees that also followed an ergonomic pattern. A sample work clothing evaluated an objective assessment and subjective assessment to compare to a current work clothing. Assessment group consists of seven subject groups and nine expert groups to evaluate external appearance and adaptability to the movements. In all aspects of the test, the result of evaluation process of the sample work clothing received more positive assessment than the current work clothing.

• Journal of the Korea Safety Management & Science
• /
• v.12 no.1
• /
• pp.51-57
• /
• 2010

Cycling that transform human energy into mechanical energy is one of the man-machine systems out of sports fields. Benchmarking means "improving ourselves by learning from others', therefore benchmarking toward dominant cyclist is necessary on field. The goals of this study were to provide important factors on multi-disciplines (kinematics, physiology, power, psychology) for a tailored-training program that is suitable to individual characteristics. Two cyclists participated in this study and gave consent to the experimental procedure. One was dominant cyclist (years: 21 yrs, height: 177 cm, mass: 70 kg), and the other was non-dominant cyclist (years: 21, height: 176, mass: 70). Kinematic data were recorded using six infrared cameras (240Hz) and QTM (software). Physiological data (VO2max, AT) were acquired according to graded exercising test with cycle ergometer and power with Wingate test used by Bar-Or et. al (1977) and to evaluate muscle function with Cybex. Psychological data were collected with competitive state anxiety inventory (CSAI-2) that was devised by Martens et. al (1990) and athletes' self-management questionnaire (ASMQ) of Huh (2003). It appears that the dominant's CV of ankle joint angle was higher than non-dominant's CV and dominant's pedaling pattern was consistent in biomechanics domain, which the dominant's values for all factors ware higher than non-dominant's values in physical, and physiological domain, and their values between cognitive anxiety and somatic anxiety were contrary to each other in psychology. Further research on multi-disciplines may lead to the development of tailored-optimal training programs applicable with key factors to enhance athletic performance by means of research including athlete, coach and parents.

• Physical Therapy Korea
• /
• v.20 no.3
• /
• pp.81-88
• /
• 2013

Active straight-leg raise (ASLR) is a physical evaluation procedure to test lumbar spine stability. Several previous studies have reported various methods to control the activation of abdominal muscles during ASLR. We investigated the effects of three different hip positions in frontal plane on abdominal muscles to increase or decrease the difficulty level of lumbar spine stability exercise during ASLR in pain free subjects. Eleven young and healthy subjects voluntarily participated in this study (6 men, 5 women; mean age=$24.0{\pm}1.2$ years, height=$160.0{\pm}7.3cm$, weight=$55.0{\pm}10.6kg$, body mass index=$21.5{\pm}2.3kg/m^2$). The subjects had three trials on each ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction. Separate repeated-measures analysis of variance (ANOVA) and the post hoc Bonferroni tests (with ${\alpha}$=.05/3=.017) were performed for each muscle among the three different hip positions in frontal plane (ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction). The ipsilateral external oblique (EO), contralateral EO, ipsilateral internal oblique/transverse abdominis (IO/TrA), and contralateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with hip $10^{\circ}$ adduction. Also, the ipsilateral EO, contralateral EO, and ipsilateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with neutral hip. These results suggest that ASLR with hip $30^{\circ}$ abduction and neutral would be useful method to strengthen the EO and IO/TrA. And, ASLR with hip $10^{\circ}$ adduction would be effective in early stages of lumbar stabilization program due to low activation of EO and IO/TrA during maintaining of ASLR position with low load.

• Journal of the Ergonomics Society of Korea
• /
• v.29 no.1
• /
• pp.39-46
• /
• 2010

The growth of function in vehicle needs complex display and control system, the In-Vehicle Information System(IVIS). Although current IVISs are widely implemented in commercial vehicles, a new form of IVIS has been recently studied in order to reduce drivers' workloads. The purpose of this study is to suggest an appropriate menu structure of a new type IVIS, to be implemented on the instrument cluster panel, using Taguchi's parameter design. In the research, firstly, functions were selected that are appropriate to control through the instrument cluster among existing functions of current IVISs by quantitative evaluation of ergonomic principles. Then, menu structure alternatives were extracted by investigating priorities to those functions selected. Finally, menu structure alternatives were evaluated through an experiment and suggest the most appropriate one by applying Taguchi's parameter design. Taguchi method was used not only for planning an experiment but also evaluating alternatives. SN ratios were a key value to evaluate the alternatives and to find the most proper one. Through the research, the most appropriate menu structure for the instrument cluster IVIS was finally suggested among the alternatives and it is expected that the results of this research could provide a guideline to the instrument cluster IVIS.

• Journal of the Ergonomics Society of Korea
• /
• v.26 no.4
• /
• pp.147-152
• /
• 2007

The aim of this study was to evaluate the musculo-skeletal symptomatic features of municipal sanitation workers and to compare differences of the musculo-skeletal symptoms by work types. We conducted descriptive cross-sectional survey concerning the musculo-skeletal symptomatic features of 315 street cleaners in Seoul and GyeongGi Province, Korea, during 2 weeks of September 2006. Questionnaires were consisted of general characteristics, occupational characteristics and musculo-skeletal symptoms. And we observed their works and evaluated their movement and posture by REBA. For work types, tools and subjective physical work loading, there were statistical difference whether or not NIOSH symptom positive on upper limb. Musculo-skeletal symptoms on upper limb were claimed from 43.2% of street cleaners, more than in 32.4% of cleaners. Musculo-skeletal symptoms on upper limb were reported higher in the group who felt their subjective physical work loading severe than in the otherwise group. The REBA results were over 'high risk stage' in street cleaners. Street cleaners had more repetitive motions than solid waste collectors on upper limbs. Works according to the criteria of musculoskeletal burdened work by the Ministry of Labor results were over 'high risk stage' of No. 2 and No. 4 in street cleaners. We found that street cleaners complained musculo-skeletal symptoms on upper limb more than solid waste collectors. This study suggests that it is necessary for street cleaners to carry out the prevention program of musculo-skeletal diseases. For street cleaner, the measure plans such as job rotation, automatic street sweepers, reducing work hours are helpful in preventing musculoskeletal symptoms on the upper limb.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.32 no.11
• /
• pp.1792-1801
• /
• 2008

This study was to develope the pesticide-proof clothes(PPC) for fruit-grower which has been well known over applied agricultural chemicals. The ergonomic evaluation of PPC were tested in two ways. Male adults volunteered the tests to evaluate the safety to pesticide in the field and the thermal comforts in the climate-chamber($30^{\circ}C$, 60%R.H.). PPC were made of 4 different fabrics. Two of them were on the market(coated non-woven and coated nylon). Others were water-repellent treatment and coated waterproof film by developed polyester. The field study was conducted for farmers growing apples to evaluate pesticide exposure. In this experiment, we collected data with patch test on the head, chest, back, right upperarm, right forearm, left thigh and left calf. From the results, the developed PPC showed the more excellent comfort than an existing PPC with nylon coated polyurethane. But the developed PPC of water-repellent fabric was penetrated into the PPC. Therefore, we designed the functional pesticide-proof clothes of 2 different developed polyester fabrics(water-repellent treatment in chest, abdomen, the lower of back, waist, and calf; coated waterproof film in head, shoulder, the upper of back, the crotch, hip, upper arm and thigh).

• IE interfaces
• /
• v.18 no.3
• /
• pp.288-296
• /
• 2005

Many jobs and activities in our daily lives require squatting postures. The fore part includes housekeepers, farmers, and welders and the latter includes a wide variety of activities such as housekeeping; planting, cultivating and harvesting various agricultural products; grinding, welding, etc. It is speculated that prolonged squatting postures without any supporting stool would gradually cause musculoskeletal injuries to workers. This study is conducted to examine the proper height of stools according to the position of the working materials and to develop wearable stools for workers with squatting posture. Forty male and female subjects participated in the experiment to find the proper height of stools according to the position of the working materials. Subjects were asked to squat and work with 3 different working positions: floor level; ankle level; shank level of 3 different stool height conditions: 10cm height; 15cm height; and 20cm height. After 5 minutes of maintaining a squatting work posture while sitting on the different height stools, Likert summated rating method as well as pairwise ranking test was applied to evaluate the user preferences for provided stools under the conditions of different working positions. The results of statistical analysis show that the subjects preferred 10cm height stool for floor level, 15cm height stool for ankle level, 20cm height stool for knee level. We thus strongly recommend to use appropriate height stools in accordance with the different working positions. Moreover, a prototype wearable stool was designed such that workers with squatting posture do not need to move the stool while they are moving about. The purpose of developing wearable stool was to decrease the physical stress and hence promote worker's health who work with squatting posture.