Eunjin Jeon

Analysis of the facial measurements of Korean Air Force pilots for oxygen mask design

This study measured the facial dimensions of Korean Air Force (KAF) pilots, to design a pilot oxygen mask, and compared them with those of Korean civilians and US Air Force (USAF) personnel. Twenty-two facial dimensions were measured for 278 KAF male pilots (KMP) and 58 KAF female pilots and cadets (KFP) using an anthropometer and a three-dimensional scanner. The KMP face measurements were found to be significantly larger (mean difference, = 0.7–26.5 mm) and less varied (ratio of SDs = 0.29–0.82) than those of Korean male civilians. The average face length, lip width and nasal root breadth of the KMP were significantly longer ( = 4.7 mm), narrower ( = − 2.4 mm), and wider ( = 5.2 mm), respectively, than those of USAF male personnel. Lastly, the KMP face measurements were significantly larger ( = 1.8–26.1 mm) than those of the KFP. Practitioner Summary: The face measurements of KAF pilots were collected and compared with those of Korean civilians and USAF personnel. The distinct facial features of the populations identified in this study are applicable to custom design of an oxygen mask for prevention of excessive pressure and oxygen leakage.

Analysis of the Facial Anthropometric Data of Korean Pilots for Oxygen Mask Design

The present study measured Korean pilots’ facial dimensions to design a pilot oxygen mask which would fit Korean pilots, and compared Korean pilots’ facial dimensions to Korean male civilians and US male pilots’ facial characteristics. The present study selected the 22 facial anthropometric dimensions related to oxygen mask design by referring to previous studies. The facial dimensions of 366 Korean male and female pilots (including 52 female cadets of the Korean Air Force Academy) were measured using Martin’s anthropometer and 3D scanner. Korean male pilots’ faces were significantly larger (mean difference = 1.3 ~ 27.0 mm) and less variable (ratio in SD = 0.29 ~ 0.85) than Korean male civilians’ faces (α = 0.05), which indicates that facial anthropometric data derived from Korean pilots should be used to design the oxygen mask for Korean pilots. In terms of criteria of the oxygen mask sizing system which is currently based upon the US Air Force anthropometric data (face length and lip width), Korean male pilots were significantly longer on face length (mean difference = 4.7 mm) and narrower on lip width (mean difference = -2.4 mm) than US male pilots (α = 0.05), which indicates that the oxygen mask sizing system as well as the oxygen mask shape should be changed for Korean pilots. Additionally, Korean male pilots have wider nasal roots (mean difference = 5.2 mm) than US male pilots, which indicates that the shape of nose of the current oxygen mask should be widened. Lastly, Korean female pilots’ facial dimensions were significantly smaller (mean difference = 0.6 ~ 26.1 mm) than Korean male pilots (α = 0.05), which indicates that Korean female pilots’ facial characteristics need to be considered in the design of oxygen masks which fit Korean pilots.

An Ergonomic Design of Flight Suit Pattern According to Wearing characteristics

The purpose of this research is to conduct a survey of the wearing characteristics of flight suits from current pilots and to design from this survey a new flight suit pattern suitable for the physical characteristics of Korean pilots. A pool of 563 pilots was surveyed in order to analyze the wearing characteristics. In order to confirm the improved effects of the newly designed suit compared to the current one, an evaluation was conducted by assessing the subjective satisfaction and objective functionality through a measurement of the range of motion. Results of the evaluation have shown that significant improvements have been made in the areas of suit that many of the respondents had indicated as being uncomfortable, such as neck circumference, armscye circumference, and crotch. This was achieved through increasing the ease in respective parts of the suit using anthropometric data of the pilot in the design process, thus correcting the pattern of the uncomfortable areas. The areas that showed the greatest improvements were the ones associated with lengthwise mobility; the fit and the mobility of the overall flight suits have ameliorated by a significant degree.

Wearing Characteristic Evaluation of Hip Protector for Hip Fracture Prevention

We surveyed the wearing characteristics of hip protectors. The problems of existing hip protectors were identified and the directions for improvement were presented. The evaluation of wearing characteristics was conducted on the 100 elderly women (60 to 85 years) with 5 types of hip protector. The questionnaire was composed of history and characteristics on falling, hip protector acceptance, preference, use characteristics and improvement requirements. The result of wearing characteristic evaluation indicated that 52% of the subject experienced falling in winter. Incidents resulting from falling occurred: outdoors (74.5%), bathroom (10.9%), and kitchen (5.5%). Body parts to be protected were in several areas: 35.6% for lumbar, 26.9% for hip joint, and 15% for hip bone. Participants prefer a belt B type design at a rate of 56.9% because it provided a sense of stability by clinging to the body and upholding the waist. Belt B type was the most appropriate in terms of fit, allowance, mobility, and design except pad thickness. To reduce the risk of hip fracture, hip protector needs to be designed in consideration of users type of fall and body shape. The pattern and size of a hip protector has to be improved in regards to the amount of discomfort. An objective evaluation is needed for the ergonomic design of a hip protector based on and analysis of 3D body image of the elderly and the shock-absorbing quality of pad.

The Improvement and Evaluation of the Flight Suit Pattern to Enhance Movement

The purpose of this study is to evaluate a new flight suit in bilateral ways; subjectively and objectively in the improvements of comfort and mobility. Seven healthy males at the age of twenties volunteered in this wearing test. They were over 177 cm in height and 92-95 cm in chest circumference, which satisfies the M95 Special` size described in the Korean Military Specifications and Standards. The subjective satisfaction was evaluated according to the criteria of ease of donning and doffing, fitness of wear, mobility, space between cloth and body, convenience in using restroom. Subjective satisfaction evaluation says that the best improvement of movement are neck circumference, chest breadth, armscye circumference, waist back length, crotch length, crotch height and body rise. According to the evaluation, improvements of mobility were conspicuous especially in parts of body like neck, breast, waist, back, and arms. When evaluating objective satisfaction, we measured a angle difference in a prescribed standard-grid on a photograph that picked up while the subject performed each motion in front of 10 cm-interval grid. As a result, the motion that had angle difference above 5 degrees were arm stretching and standing on single leg holding at forward or at his side. Bending necks and waist, crouching also had angle difference of over 5 degrees. The improvements are discussed from the viewpoint that the increased ease in parts of armscye circumference and crotch in new flight suit pattern.

Development of a Sizing System and a Draping Pattern for Hip Protector based on 3D Data Analysis of Korean Older Women

This study aimed to develop an optimal sizing system and a draping pattern for hip protector based on an analysis of anthropometric characteristics of Korean older women. A hip protector is a specialized form of pants or underwear containing pads along the outside of each hip. The 3D body scan data of Korean older women were analyzed to identify their anthropometric characteristics and a four-size system with 93% of population accommodation was developed by clustering analysis based on key dimensions derived from factor analysis. The sizing system consists of small/short, large/ short, small/tall, and large/tall. A 3D physical model and hip pads were fabricated; then, a hip protector was draped on the 3D model and hip pads. The sizing system of hip protector was analyzed in terms of size and shape and a draping pattern was compared on back center, back side, front side, front center and pad. Lastly, the pattern deformation and clothing pressure were analyzed using the virtual clothing system CLO. Virtual system have disadvantage of not to suggest the objective value. In the future research the wearing comfort and impact absorption of the hip protector needs to be tested and then a hip protector design will be finalized by considering the hip protector’s size, material, comfort testing results, aesthetic appeal, protection effectiveness, and practical utility of everyday use.

3D scan to product design: Methods, techniques, and cases

3D scanning technology has derived great opportunities for ergonomic product designs. This paper is aimed to introduce various research cases and methods based on 3D scanning have conducted by an ergonomics laboratory in South Korea. Sizing systems and representative 3D models developed on anthropometric measurements and 3D scan images with technical know-how were applied to the design of various products. Head, face, ear, upper limb, and waist parts, and full body in seated were anthropometrically analyzed for the design of headwear (e.g., helmet, goggle, and headphone), oxygen mask, earphone, arm-wear (e.g., watch, armband), hip protector, and vehicle seat, Customized software for the efficient analyses such as measurement of anthropometric dimensions, analysis of sizing systems, extraction of representative models, and virtual fit evaluation between products and the body were developed and applied in the product design process with massive 3D images. Representative models (e.g., torso and head) were printed in 3D for effective usage to the design and evaluation of related products. Advanced methods and techniques such as finite element modeling, morphing, and skin deformation have been applied to 3D scanned images for an advanced design of product shapes in further researches.

Wearing Comfort Evaluation of a Summer Flight Suit to Improve Ventilation

This study verified the effect of summer flight ventilation developed in a previous study based on wearing comfort evaluation. Seven healthy males in their twenties volunteered for this experiment conducted in aclimatic cham- ber. The experiment consisted of three consecutive periods of rest (20 minutes), running on a treadmill (10 minutes) and recovery (20 minutes). A comparative evaluation was conducted on the general flight suit which had no ventilation holes and summer flight suit that usesubjective satisfaction measures and objective measures. The subjective satisfaction was evaluated according to the criteria of temperature sensation, wet sensation, thermal comfort and fatigue sensation. The objective satisfaction was measured by skin temperature, microclimate (temperature and humidity), sweat rate and ther- mography. The comparative wearing evaluation identified the summer flight suit decreased the temperature between skin and suit by 0.42 o C (upper arm), 0.9 o C (calf) and the skin temperature by 0.3 o C (shoulder), 0.4 o C (upper arm), 0.5 o C (calf) as compared to the general flight suit. The humidity inside the summer flight suit decreased at head (7.73%), shoulder (5.86%), upper arm (5.26%), and calf (8.73%) compared to the one inside the general flight suit. Thermography showed that the air flowed through ventilation holes (neck and armpit). The design of ventilation holes applied to the summer flight suit can be applicable to overall clothing that requires thermal comfort such as dust-free garments, mechanical cloth- ing and combat uniforms.

An Ergonomic Evaluation of Convex Probe Designs Using Objective and Subjective Measures

Use of a convex probe suitable to the hand and operating motion of the probe can contribute to prevention of sonographers from musculoskeletal disorders at work. The present study presents an ergonomic evaluation process customized to convex array ultrasound probe design. Various convex probe designs were evaluated by a mix of nine sonographers and medical doctors in terms of EMG activities of the upper extremity muscles, motion ranges of the upper extremity joints, and subjective satisfaction measures. A randomized controlled testing was administered for the probe designs in a simulation workstation at a designated speed of tilting, pushing, and rotating of convex probe. The subjective satisfaction results were found effective to identify preferred design features in detail, while the EMG and motion analysis results to identify a preferred probe design overall in terms of muscular load at the hand and postural comfort of the forearm.