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Longitudinal Trend of Prevalence of Meeting Physical Activity Guidelines among Korean Adults
Junghoon Kim(Junghoon Kim) 사피엔시아 2017 Exercise Medicine Vol.1 No.-
OBJECTIVES: At present, almost nothing is known about longitudinal trends in the proportion of Korean adults meeting recommended guidelines for physical activity or the inter-related factors. The purpose of this study was to investigate the longitudinal trends in how Korean adults met new guidelines for physical activity between 2008 and 2013 and to evaluate a range of factors that could have influenced these trends. METHODS: Analysis involved a dataset of 36,009 adults aged ≥20 years who participated in the Korea National Health and Nutrition Examination Survey 2008-2013. The volume of physical activity and muscular activity were assessed using a self-reported questionnaire, and each domain of activity was characterized as being either low or high, based upon physical activity guidelines for Korean adults. RESULTS: Based on new physical activity guidelines, 22.0%, 26.6%, and 36.8% of Korean adults met the guideline requirements for moderate, vigorous, and moderate-to-vigorous physical activity, respectively; 21.8% adults met the requirements for muscular activity. The odds ratio for meeting the requirements of the physical activity guidelines was significantly lower in the elderly population, in females, and in participants with low income. Moreover, the longitudinal trend for meeting the guidelines for physical activity showed a significant reduction from 2008 to 2012. CONCLUSIONS: In conclusion, the self-reporting questionnaire used in the present study showed that ~35% of Korean adults met the guidelines for physical activity. Furthermore, the longitudinal trend for meeting physical activity guidelines showed a significant reduction between 2008 and 2012. Finally, our findings showed that physical activity estimates for Korean adults vary substantially depending on socio-demographic characteristics.
Kim, Shin Ae,Das, Sumit,Lee, Howon,Kim, Junghoon,Song, Yun Mi,Kim, In Sook,Byun, Kyung Min,Hwang, Soon Jung,Kim, Sung June Wiley Subscription Services, Inc., A Wiley Company 2011 Biotechnology and bioengineering Vol.108 No.6
<P><B>Abstract</B></P><P>Matrix mineralization is a terminal process in osteoblast differentiation, and several approaches have been introduced to characterize the process in tissues or cultured cells. However, an analytical technique that quantitates in vitro matrix mineralization of live cells without any labeling or complex treatments is still lacking. In this study, we investigate a simple and enhanced optical method based on surface plasmon resonance (SPR) detection that can monitor the surface‐limited refractive index change in real‐time. During monitoring MC3T3‐E1 cells in vitro culture every 2 days for over 4 weeks, the SPR angle is shifted with a greater resonance change in cells cultured with osteogenic reagents than those without the reagents. In addition, the SPR results obtained have a close relevance with the tendency of conventional mineralization staining and an inductively coupled plasma‐based calcium content measure. These results suggest a new approach of a real‐time SPR monitoring in vitro matrix mineralization of cultured cells. Biotechnol. Bioeng. 2011; 108:1473–1478. © 2010 Wiley Periodicals, Inc.</P>
Junghoon Kim,Juhee Lee,Phil Kim,Jangho Lee,Seungkeun Kim 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.6
This paper presents a preflight diagnosis method for detecting multicopter’s motor abnormalities using jig equipment data. While operating multicopters on a regular basis, determining whether it can perform the flight or not is important. For this, we use disturbance observer’s output as a feature for detecting degree of the abnormality by Gaussian process regression. During the ground inspection test where most of the disturbances are under control, motor degradation and disturbances are significantly correlated. Then, motor degradation can be estimated using the Gaussian process regression. To create multivariate output models against different degrees of motor abnormalities, we use multitask a Gaussian process regression model. To verify the performance of the proposed approach, actual preflight tests on a ground jig device developed in-house were performed with an actual quadcopter drone.
과산화수소/케로신 소형 이원추진제 추력기의 설계 및 성능특성에 관한 연구
김정훈(Junghoon Kim),이재원(Jaewon Lee),전영진(Youngjin Jeon),채병찬(Byoungchan Chae),전준수(Junsu Jeon),김유(Yoo Kim),김선진(Sunjin Kim) 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.5
본 연구에서는 고농도 과산화수소와 케로신을 각각 산화제와 연료로 사용하는 소형 이원추진제 추력기의 설계/제작 및 인젝터 성능특성 파악을 위한 수류시험을 수행하였다. 본 개발모델에서는 점화기, 인젝터, 막냉각 시스템을 통합하여 운용이 가능한 구조의 믹싱헤드를 적용하였으며, 각 부분으로의 공급유량 변경이 가능하도록 하여 최적 설계의 실험적 검증 및 효율성을 극대화하고자 하였다. 마지막으로 수류시험을 통해 인젝터 유량 및 추진제 분사패턴을 확인하였으며, 믹싱헤드의 설계 타당성을 검증하였다. The small-sized bi-propellant thruster using a high concentrated hydrogen peroxide and kerosene as the oxidizer and fuel was designed and fabricated in this study. The water cold-flow test was performed to verify the performance characteristics of the injector. The mixing head assembly used in this model thruster was designed as a structure to combine igniter, injectors and film cooling, which are capable of regulating each mass flowrate. This maximize the experimental verification and efficiency of the design optimization. Finally, the mass flowrate and spray pattern of injector were evaluated by the hydraulic test. Therefore, the design validity of the mixing head was verified.
김정훈(Junghoon Kim),김의석(Uiseok Kim),김지윤(Jiyoon Kim),강민규(Minkyu Kang),최항석(Hangseok Choi) 한국지반환경공학회 2022 한국지반환경공학회논문집 Vol.23 No.1
확장형 강관말뚝은 강관말뚝 내부에 확관장비를 삽입하여 강관을 확관하여 강관의 단면적을 증가시키는 공법으로 기존에 사용되는 마이크로파일과 비교하여 말뚝의 성능을 향상시킬 수 있는 공법이다. 본 연구에서는 실제 현장에서 강관의 확관이 가능한 확관장비를 개발하였다. 일련의 실내시험 및 현장시험을 통해 개발된 확관 장비의 강관 확장 성능을 확인하였다. 확관장치의 강관확관능력과 확관이 가능한 범위를 평가하기 위해 강관 확관장치의 최대압력에 대한 변형량과 확관시간을 측정한 결과, 강관두께가 얇을수록 변형량이 크게 발생하였으며 확관시간은 증가하였다. 두께 4.0㎜ 강관의 경우 두께 2.9㎜ 강관과 비교하여 변형량은 약 30% 적게 발생하였으나, 확관시간이 줄어드는 효과(약 40% 감소)를 얻을 수 있었다. 그리고 실제 지중에서 강관의 확관이 가능한지 확인하기 위해 현장 확관시험을 수행하였으며 지중에서 확관 후 확관 상태를 확인한 결과, 본 연구에서 개발한 강관 확관장치는 지중응력 조건에서도 강관 확관 성능을 발휘할 수 있음을 확인하였다. 마지막으로 확관하기 전 원상태의 강관과 확관 후 강관의 재료성능을 비교하여 확관형 강관말뚝의 역학적 안정성을 검증하였다. Expandable steel pipe piles are installed by inserting expansion equipment to increase the cross-sectional area of steel pipes, which can improve the pile performance compared to micro-piles. In this paper, a hydraulic expansion device was developed to expand steel pipe piles in practice. A series of laboratory and field tests were conducted to verify the performance of the developed expansion device to expand steel pipes. The expansion capability and expandable range was evaluated by measuring the strain and expansion time at the maximum pressure of the hydraulic expansion device. The thinner steel pipe, the larger strain but longer expansion time required in the test. For example, the 4.0-㎜-thick steel pipe showed strain reduction by 30% and a decrease in the required expansion time by 40% compared to the 2.9-㎜-thick steel pipe. In addition, in-situ expansion tests were performed to verify the expandability of steel pipes under the ground, and the exhumed specimen showed clear expanded sections. The structural integrity was determined by comparing the material performance the original and expanded specimens.
Development of Particle Flow-Based Inflatable Robot Body for Shape Rigidity Modulation
Hyunho Kim,Sangjoon Jonathan Kim,Junghoon Park,Handdeut Chang,Namkeun Kim,Yeongjin Kim 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.10
Disaster robots are needed to perform various tasks through narrow gaps between building debris to be used for rescue. A soft material-based disaster robot can have easy access to the rescue site through the narrow gaps. To ensure the robust control and better performance of the soft robot operation, a joint stiff ness modulation mechanism is required. In this paper, we have proposed a noble stiff ness modulation mechanism that includes shape change and self-assembly by using a particle flow-based inflatable robot body. We analyzed the particle filling completion time by injecting air and particles at a constant pressure into the soft chamber depending on several parameters (the size of the particle, the size of the reservoir, the volume ratio between the chamber volume and the total volume of the particle, and the injected air pressure). Of these, the most dominant factors influencing the completion time were particle size and pressure. It was observed that the smaller the size of the particle, the shorter time. The completion time tended to decrease as the air pressure increased.