소음수준에 따른 신체자세동요의 변화

박성하,이승원,Park, Sung-Ha,Lee, Seung-Won 대한인간공학회 2006 大韓人間工學會誌 Vol.25 No.3

Loss of postural balance can possibly lead to increased risk of slips and falls in work places. Present study was performed to investigate the effects of noisy environments on postural stability during standing. It is known that a sound is characterized by the frequency and pressure level of the sound. Therefore, effects of the frequency and pressure level on postural stability were of primary concern. Ten male subjects participated in the experiment. Subject's center of pressure(COP) position was collected on a force plate while they were exposed to different frequency and pressure levels of the sound. Measured COP was then converted into the length of postural sway path in both anterior-posterior(AP) and medio-lateral(ML) axis. Results showed that the length of sway path in AP axis was significantly affected by the frequency of sound. The length of sway path was lowest at frequency level of 2000Hz and increased below and above this frequency range. The sound pressure level, however, did not significantly affect the postural sway length in both AP and ML axis. The results imply that industrial workers in noisy environments should be aware that their abilities of postural balance can be disturbed significantly.

토글식 전동사출성형기의 타이바 변형에 관한 연구

박성하(Sung-Ha Park),정현석(Hyun-Suk Jung) 산업기술교육훈련학회 2012 산업기술연구논문지 (JITR) Vol.17 No.4

Injection molding machine plays an important role in making plastic parts. Plastic resin is used to connect barrel to nozzle in injection unit, and new product is made according to this mold pattern. Precise plastic manufactures are being used in lots of industry areas recently. So the performance of injection molding machine’s control system, such as reproducibility, repeatability, etc. is widely studied nowadays. This thesis proposed the relation between the deformation of platen caused by clamping force and the bending stress, elongation at the tie-bar in Toggle type injection molding machine. Results showed that the bending stress of the tie-bar caused by platen deformation is less than 17.2% of average tensile stress. Through the reliability evaluation of the most important terms of injection unit, the method of evaluating the tie-bar elongation is proposed and verified.

Effects of Abnormal Neck Posture on Postural Stability

Sung Ha Park(박성하) 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.2

Postural instability can increase the likelihood of hazardous slip and fall accidents in workplaces. The present study intended to extend understanding of the effect of abnormal neck posture on postural control during quiet standing. The effect of body fatigue on the postural control was also of primary concern. Twelve healthy undergraduate students volunteered to participate in the experiment. Standing on a force platform with the neck neutral, flexed, extended, or rotated, subjects’ center of pressures (COP) were measured under the two levels of body fatigue. For the fatigue condition, Subjects exercised in a treadmill to meet the predetermined level of body fatigue. Analyzing the position coordinates of COPs, the length of postural sway path was assessed in both medio-lateral (ML) axis and anterior-posterior (AP) axis. Results showed that, in AP direction, neck extension or rotation significantly increased the sway length as compared with neck neutral. Neck extension led to greater sway length compared to neck rotation. Neck flexion did not differ from neck neutral. The sway length in the AP direction also became significantly larger as the body fatigue accumulated after treadmill exercise. In ML direction, as compared to neutral posture, the neck extension, flexion, or rotation did not significantly affect the length of postural sway path. However, the sway length seemed to increase marginally with the neck extended during the fatigued condition. This study demonstrates that abnormal neck posture may interfere with postural control during standing. The ability to maintain postural stability decreases significantly with the neck extended or rotated. Body fatigue leads to postural instability further.

바닥면의 교란에 따른 자세균형능력의 변화

박성하(Sung Ha Park)․,이승원(Seung Won Lee) 한국산업경영시스템학회 2008 한국산업경영시스템학회지 Vol.31 No.4

This study was aimed to understand the effects of perturbed floor surface on human postural stability while standing. Ten subjects were asked to stand quietly on the surface with two angles of inclination (0° and 5°), two contamination conditions(dry and oil-contaminated), and three commercial floor materials (ceramic tile, coated wood, and vinyl tile). During each trial, a force plate with data acquisition systems was used to collect subject’s center of pressure (COP) position. Measured COPs were then converted into the length of postural sway path in both subject's anterior-posterior (AP) and medio-lateral (ML) axis. Results showed that the length of sway path in ML axis was significantly affected by the angle of inclination and the type of floor material. The sway length was increased significantly at the inclination angle of 5° and on the vinyl tile, respectively. The contamination condition, however, did not significantly affect the postural sway length in both AP and ML axis. The results imply that a proper treatment of floor surface and material is critical to preserving postural balance while standing.

외식업체의 제휴카드 할인프로그램이 이용고객의 지각된 가치, 태도, 구매의도, 재방문에 미치는 영향

박성하(Park, Sung-Ha),이수범(Lee, Soo-Bum) 한국호텔외식관광경영학회 2014 한국호텔외식경영학회 학술발표논문집 Vol.2014 No.12

인터넷 인증 및 2차 생성 파일 암호화를 이용한 소프트 웨어 부정 사용 방지 기술

박성하 ( Sung-ha Park ),채동규 ( Dong-kyu Chae ),김상욱 ( Sang-wook Kim ) 한국정보처리학회 2014 한국정보처리학회 학술대회논문집 Vol.21 No.2

소프트웨어의 불법 복제 및 인증을 거치지 않은 부정 사용 등이 큰 문제가 되고 있다. 소프트웨어 부정 사용을 막기 위해 usb 인증, 시리얼 키 인증, 서버접속을 통한 인증 등 다양한 방법들이 존재해 왔다. 그러나 이러한 기술들의 우회 방법들이 상당수 공개된 실정이다. 본 연구에서는 보다 강화된 인터넷 인증 기반의 불법 사용 방지 기술을 제안하고자 한다. 뿐만 아니라 소프트웨어를 사용해 만들어 낸 2 차 창작물 또한 보호하는 방법을 제시 하고자 한다.

첨단 컴퓨터 하드디스크 윤활제로 사용되는 Perfluoropolyethers / Phosphazene Mixtures 의 분해 특성

박성하(Sung Ha Park),천상욱(Sang Wook Chun),D . J . Perettie,F . E . Talke,강호종 한국고분자학회 1999 폴리머 Vol.23 No.1

Bi-In계의 기계적 합금화에 의한 미세조직에 관한 연구

박성하(Sung-Ha Park),김중호(Jung-Ho Kim) 산업기술교육훈련학회 2011 산업기술연구논문지 (JITR) Vol.16 No.4

Recently, mechanical Alloying(M/A) process of Bi-In powder system which has negative mixed enthalpy and various intermetallic compounds was investigated. The solidification process on the uniform refinement of microstructure and the forming of non-equilibrium phase was examined by varying alloying time and composition materials. When the experiment wasdone in Bi-30at%In and Bi-50at%In, intermatellic compounds were formed at 2 minutesin the early stage of M/A, and most of them are known as BiIn, BiIn2 and Bi3In5. Experimental results indicate that the constant saturation values are obtained at the early stage of mechanical alloying process due to the refinement of grain size and work hardening.

왕호장 열매의 항염증 효과

박성하 ( Sung Ha Park ),정현정 ( Jeong Hyeon Jeong ),박병준 ( Byoung Jun Park ),정태화 ( Tae Hwa Jeong ) 대한화장품학회 2015 대한화장품학회지 Vol.41 No.3

본 연구에서는 왕호장 열매 추출물(FSR)의 항염증 효과를 측정하였다. 왕호장 열매 추출물은 RAW 264.7 macrophage 세포에서 염증 사이토카인(1L-1β, IL-6, TNF-α)의 발현을 억제하였으며, 농도 의존적으로 NO 생성을 억제하고, 그 효과는 100 μ g/mL 농도에서 51%로 나타났다. 뿐만 아니라, iNOS와 COX-2의 mRNA와 단백질 발현을 모두 억제함을 확인하였다. 따라서 왕호장 열매 추출물은 항염증 효능을 갖는 화장품 소재로서의 개발 가능성이 클 것으로 기대된다. To develop a new anti-inflammation agent for cosmetics, we investigated the anti-inflammatory activity of Fallopia sachalinensis RonseDecr. fruit extracts (FSR). FSR inhibited the pre-inflammatory cytokines (1L-1β, IL-6, TNF-α) and reduced NO production of RAW 264.7 macrophage cells in a dose-dependent manner and decreased the activity to about 51% at a concentration of 100 μ g/mL. FSR suppressed not only the mRNA expression of iNOS and COX-2, but also the protein expression of iNOS and COX-2 in macrophage. The results suggested that FSR has considerable potential as a cosmetics ingredient with an anti-inflammatory effect.

전신 피로와 시야 제한이 자세균형 능력에 미치는 영향

박성하(Sung Ha Park) 한국산업경영시스템학회 2016 한국산업경영시스템학회지 Vol.39 No.3

Loss of postural stability can possibly lead to slip and fall accidents in the number of workplaces and everyday life. This study was aimed to examine the effects of whole body fatigue and partially limited visual field on the ability of maintaining postural balance during quiet standing. A group of twelve healthy male subjects participated in the experiment. Before and after experiencing the whole body fatigue induced by bicycling exercises, the position coordinates of subject’s center of pressure (COP) were obtained under the two levels of visual field condition (i.e., open visual field and limited visual field). Four levels of the whole body fatigue examined were rest, 300watt, 600watt, and 900watt. Position coordinates of COPs measured on a force plate were then converted into the total length of postural sway path in both the medio-lateral (ML) direction and the anterior-posterior (AP) direction. Two-way ANOVA result showed that the length of sway path in the AP direction became significantly larger as the whole body fatigue accumulated. Post-hoc test revealed statistically significant differences between rest and 900watt and between 300watt and 900watt. The significant increase of the sway length was also found when the visual field was partially obstructed by the boxes. In the ML direction, however, there was no statistically significant difference of the postural sway in both the AP and ML directions. The results imply that the ability of maintaining postural stability can be reduced significantly due to such tasks along with whole body fatigue. The postural balance can also be impaired by the limited visual field.