Living with multiple sclerosis: A family's narrative

Yongchul Chung 한국운동재활학회 2013 한국운동재활학회 학술대회 Vol.2013 No.1

Developing youth through sport: Strategies used by ten coaches

( Yongchul Chung ) 한국스포츠정책과학원(구 한국스포츠개발원) 2017 International Journal of Applied Sports Sciences Vol.29 No.1

The purpose of this study was to identify effective strategies for life skill development utilized by coaches. Ten (10) veteran football coaches were recruited and interviewed. Each interview lasted approximately for two hours. All recorded data were transcribed verbatim and later used for further analyses. The results were presented in 13 parts organized by key interview foci: the role of academic coach; the typical day of academic coach; key components for program success; the goals of the academic coach; success stories; effective strategies; ineffective strategies; strengths of academic coaches; weaknesses of academic coaches; strengths of the program; limits of the program; gender/ethnic issues; and recommendations for future academic coaches. Positive youth development strategies were categorized into two hierarchical levels. One is global macro level strategies and the other is specific micro level ones. Based on the interviews, a number of youth development strategies, both in macro and micro level, perceived to be effective were identified. However, it should be noted that while the coaches perceived these strategies were effective, they were not viewed as a panacea for all athletes in all situations. Finally, based on findings from the current study, a model for effective life skills development strategies was proposed

Identification of Flexion Withdrawal Reflex Using Linear Model in Spinal Cord Injury

Yongchul Kim,Youngil Youm 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.8

The aim of this study was to identify the characteristics of the flexion withdrawal reflex modulated by the hip angle and hip movement in spinal cord injury (SCI). The influence of the hip position and passive movement were tested in 6 subjects with chronic SCI. Each subject placed in a supine position and lower leg was fixed with the knee at 5~45 degree flexion and the ankle at 25~40 degree plantar flexion. A train of 10 stimulus pulses were applied at 200 ㎐ to the skin of the medial arch to trigger flexion reflexes. From results of the regression analysis, static properties of normalized muscle activation of flexor muscles have the linear relationship with respect to hip angle (P<0.05). In order to verify the neural contribution of flexion reflex, we compared the static and dynamic gains of estimated muscle activations with measured EMG of ankle flexor muscle. Form this study, we postulate that the torque and muscle response of flexion withdrawal reflex have linear relationship with hip angle and angular velocity.

Area-efficient Radix-3<SUP>2</SUP> FFT Processor for Hand Gesture Recognition Radar

Yongchul Jung,Jaechan Cho,Seongjoo Lee,Yunho Jung 대한전자공학회 2019 Journal of semiconductor technology and science Vol.19 No.3

We propose an area-efficient fast Fourier transform (FFT) processor for hand gesture recognition (HGR) radar and present its hardware design and implementation results. To estimate finger motion, the FFT processor should support at least 600~720-point operation for three-channel input data streams. Hence, we propose three-channel 729-point FFT processor based on the radix-3<SUP>2 </SUP>algorithm and a multipath delay commutator (MDC) pipeline architecture, which minimizes the number of nontrivial multiplications. Moreover, the FFT processor was designed using hardware description language (HDL) and synthesized to gate-level circuits using a standard cell library for 65 nm CMOS process. The proposed architecture results in a logic gate count of 219 K with die size of 0.81mm2 and required memory of 18 KB, which can be suitable for compact HGR radar, as it has a smaller area than similar processors.

Movement Analysis of Elderly People during Ingress/Egress from Different Seat Heights

Yongchul Kim 대한인간공학회 2011 大韓人間工學會誌 Vol.30 No.5

Objective: The aim of this study was to investigate the influence of seat heights for optimizing the ingress/egress performance in the elderly people. Background: Recently elderly users have been increasing in number and the ease of ingress/egress of the vehicle becomes an important issue. Method: Seven elderly subjects participated in this study(age: 71.7±3.6yr, height: 167.7±5.4㎝, weight: 68.1±11.5㎏). Each subject performed the sitting and rising task from comfortable seated position on the chair under the following conditions: (1) with a lumbar support and (2) without a lumbar support. We measured EMG activities of seven muscles(tibialis anterior, soleus, gastrocnemius, vastus lateralis, rectus femoris, biceps femoris and erector supinae) and ranges of motion in lower limb during sitting and standing from three different heights (400㎜, 500㎜ and 600㎜ from ground) of slide-up seat. Results: Muscle activities and angular movements of hip and knee joints during standing-up and sitting-down with a high seat height(600㎜) were reduced mean 30.4% in extensor muscles, 57.11% in flexor muscle, 18.74% in erector muscle and 31.0% in joints compared with a low seat height(400㎜). Conclusion: Muscle activities and joint movements in hip and knee were reduced when rising/sitting from a high seat height(600㎜) compared with a low seat height(400㎜). Application: This study can be used to design vehicle that are easy to get in and out of by older peoples with or without impairments.

The movement analysis of caregivers for transferring of a disabled person from wheelchair to car seat

Yongchul Kim,Younghyun Kim,Youngseon Yang,Woochul Park,KunminRhee 한국재활복지공학회 2008 한국재활복지공학회 학술대회논문집 Vol.2008 No.11

The aim of this study was to examine the influence of seat height on the movement of caregiver for transferring of a disabled person from wheelchair to car seat. Five female volunteers served as caregivers; two persons with disabilities and one health volunteer served as passive disabled person. To analyze the movement of a caregiver, we measured the activities of six muscles with surface electrodes and joint angle responses of the hip and knee with electrical goniometers. The caregivers performed transferring task at three different seat heights (400, 500 and 600mm from the floor) in order to investigate the effects of a car seat on transferring movement of a people with disability. From the experimental results, when caregivers were putting a disabled person down a seat, the hip and knee joint angles were decreased 31.9% and 24.7 % in 600mm seat height than 400mm seat height, respectively. The integrated EMG activity of erector spinae was decreased 16.3% in 600mm seat height, compared with 500mm seat height. However, the integrated EMG activity of rectus femoris for lower limb in 600mm seat height was increased 33.3% than 500mm seat height.

Throughput and Fairness Analysis of Channel-hopping Scheme under Smart Jammer Attacks in IEEE 802.11 WLANs

Yongchul Kim 한국통신학회 2014 한국통신학회 학술대회논문집 Vol.2014 No.6

Set-point Tracking Algorithm of the System Air-Conditioning With Third-Party Thermostat

Yongchul Cho,Yun-Jung Lee 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

Recently, as the demand for energy saving increases in the North American air conditioning market, the use of a high-efficiency VRF(Variable Refrigerant Flow) system is increasing and compatibility with a thermostat which was traditionally used for unitary system control in the US market is also required. Since it is difficult to achieve high efficiency from the simple interlocking between the thermostat which is a simple ON/OFF controller and the VRF system which is a continuous device, a control algorithm that minimizes energy consumption while maintaining a comfort indoor heating and cooling environment is needed. In order to solve this, this paper suggests control algorithm for achieving energy saving under this combination by tracking the thermostat set-point from first thermo-off signal and return air temperature. As a result, when the proposed algorithm was applied under the same conditions, the power consumption was saved up to 35% in cooling operation and 4% in heating operation compare to condition without the algorithm. In the case of heating, there was meaningful result that the defrost inrush time is shortened due to a decrease in temperature fluctuation and a reduction in the compressor operating frequency.

승용차 자연 환기성능 향상을 위한 REAR부 유동특성 연구

김용철(Yongchul Kim),나원균(Weonkyun Na) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

It needs to deforgging system in vehicle for the purpose of the safe driving and pleasantness in side of vehicle. It is very important for deforgging system in a vehicle to ventilation performance. In this study, the flow characteristics for improvement of the ventilation performance in rear part of vehicle was performed computationally using CFD. Control factors are gap of between rear glass and rear package tray, extractor hole position and extractor hole area. Incase of gap and extractor hole position change, Relative pressure drop is improved about 19%. And incase of extractor hole position and area change, Relative pressure drop is improved about 37.6%. Control factors have to apply to at the same tine in order to increase relative pressure drop

원격탐사 기반 토양수분을 이용한 가뭄평가

신용철 ( Yongchul Shin ),최경숙 ( Kyung-sook Choi ),정영훈 ( Younghun Jung ),박경원 ( Kyungwon Park ) 한국농공학회 2015 한국농공학회 학술대회초록집 Vol.2015 No.-

전 세계적으로 원격탐사 기반 토양수분을 이용한 농업 및 산림 가뭄평가기법들이 개발되었으나 산악지형에 산림이 우세한 우리나라의 경우 원격탐사된 토양수분 자료의 불확실성이 증가하게 된다. 또한, 토양으로부터 수분을 공급받는 작물의 경우 기상뿐만 아니라 토양특성에도 큰 영향을 받기 때문에 기상특성만을 고려한 가뭄지수는 지표 고유의 특성을 반영하는데 있어서 한계가 있다. 본 연구에서는 농업 및 산림 지역의 가뭄 평가시 기상 및 지표특성을 함께 고려하기 위하여 원격탐사된 토양수분과 수문모형 기반의 자료동화 기법을 연계하였다. LANDSAT(30 m X 30 m) 및 MODIS(500 m X 500 m) 이미지 자료를 이용하여 공간적으로 분포되어 있는 토양수분을 산정 하였다. 토양수분 이미지 자료의 경우 공간적으로 분포되어 있는 토양수분 분포를 측정할 수 있는 장점이 있으나, 기상 특성에 따라서 이미지 자료가 오염될 경우 시간적으로 불연속적인 단점이 있다. 이러한 시간적 해상도의 단점을 보완하기 위하여 프로세스 기반의 1-D HYDRUS 모형과 최적화 알고리즘을 연계한 자료동화기법을 이용하였다. 자료동화기법은 시간적으로 불연속인 각각의 토양수분 이미지로부터 HYDRUS 모형의 입력변수인 토양의 수리학적 매개변수를 도출하여 일별로 연속적인 토양수분 자료를 재생산 한다. 본 연구기법은 다양한 해상도에서 연속적인 토양수분 자료를 산정 및 가뭄평가에 사용함으로써 우리나라 지형특성을 고려하여 효율적으로 가뭄을 관측 및 예측하는데 기여할 수 있다.