Multi Channel LED 조명 Module 구동에서 최대 효율을 위한 최대 Channel 전압 감지회로

김현식,김기원,김기훈,김유신,송상빈,Kim, Hyun-Sik,Kim, Ki-Woon,Kim, Gi-Hoon,Kim, Yu-Sin,Song, Sang-Bin 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.11

LED is divided to multichannel in order not to exceed a certain voltage in aspects of electric standard. However, it's not possible to know in accordance with what channel SMPS controls the constant voltage and current. In order to solve this problem, it needs to detect the maximum LED String voltage which is applied to LED control circuit, and it is possible to minimize the voltage drop when a difference of LED string voltage occurs by each channel if LED is controlled by the maximum LED string voltage detected. In addition, it is also possible to maximize the efficiency of LED if change LED voltage by detecting the maximum voltage. Feasibility of this claim was verified through implementation of the circuit.

근위축성 측삭경화증 환자 1년 후 추적 조사

김현식,송봉근,박만용,임나라,김성하,김성철,Kim, Hyun-Sik,Song, Bong-Kuen,Park, Man-Yong,Lim, Na-Ra,Kim, Sung-Ha,Kim, Sung-Chul 대한약침학회 2010 Journal of pharmacopuncture Vol.13 No.1

Objectives : This study was to investigate the effects of Oriental medical treatment on ALS. Methods : We investigated 12 ALS patients which were admitted to Gwang-Ju O.M.hospital for 3 months and follow-up at 8 months after discharge. All patients were treated by SAAM-acupuncture, herb medication, Bee venom Pharmacopuncture therapy, Needle-embedding therapy, etc and after discharge self-therapy at home. We evaluated patients using the Amyotrophic lateral sclerosis Functional Rating Scale-Revised(ALSFRS-R), Medical Research Council (MRC) Scale. Results : After 1 month, mean ALSFRS-R score of patients was $29.08{\pm}7.99$, 2 months $28.70{\pm}7.17$, 3 months $28.16{\pm}8.23$, 1 year $21.33{\pm}9.93$ and mean MRC Scale of patients was $25.34{\pm}8.45$, 2 months $25.34{\pm}8.45$, 3months $21.56{\pm}9.20$. But in both cases, the variation was not statistically significant. Conclusions : We think that the results of this case be a pilot study that proves the effect of Oriental Medical treatment on ALS.

가변 시상수를 이용한 자동 노출제어 시스템

김현식,이성목,장원우,하주영,김주현,강봉순,이기동,Kim, Hyun-Sik,Lee, Sung-Mok,Jang, Won-Woo,Ha, Joo-Young,Kim, Joo-Hyun,Kang, Bong-Soon,Lee, Gi-Dong 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.2

In order to obtain a fine picture, a camera has many convenient functions. Its representative functions are Auto Focus(AF), Auto White Balance(AWB) and Auto Exposure(AE). In this paper, we present the new algorithm of Auto Exposure control system, one of its useful functions The proposed algorithm of Auto Exposure control system is based on IIR Filter with Variable Time Constant. First, in order to establish the standards of exposure control, we compare change of the picture luminance with luminance of an object in the Zone system. Second, we make an ideal characteristic graph of luminance by using the results. Finally, we can find the value of the right exposure by comparing an ideal characteristic graph of the luminance with the value of the current expose of a scene. We can find an appropriate exposure as comparing the ideal characteristic graph of the luminance with current exposure of a scene. In order to find a suitable exposure state, we make use of IIR Filter instead of a conventional method using micro-controller. In this paper, the proposed system has therefore simple structure, we use it for compact image sensor module used in the handheld device. 사진을 찍을 때 카메라는 보기 좋은 사진을 얻을 수 있도록 많은 기능을 제공하고 있다. 대표적인 기능으로 자동 초점거리 조정(Auto Focus), 자동 색온도 보정(Auto White Balance), 자동 노출 조정(Auto Exposure)이 있다. 본 논문에서는 편리한 기능들 중 하나로서 새로운 자동 노출제어 시스템을 제안한다. 본 논문에서 제안하는 자동 노출제어 시스템은 가변 시상수(Variable Time Constant)를 가지는 IIR Filter를 이용한다. 먼저 노출제어의 기준을 정하기 위해서 사진에서 밝기변화와 Zone System에서 보여주는 사물의 휘도정보를 비교하여 이상적인 휘도변화 특성 그래프를 얻는다. 얻어진 이상적인 휘도 변화 그래프와 현재의 노출설정을 비교하여 적정 노출의 설정을 찾는다. 제안하는 자동 노출제어 시스템은 적정 노출을 얻을 수 있는 설정으로 조정하기 위해 기존의 마이크로 콘트롤러 등을 이용하여 구현하는 방법과 달리 IIR Filter를 사용하므로 간단한 구성을 가지며 콤팩트 이미지 센서모듈(ISM)를 구성하기 위하여 사용할 수 있다.

Mg-Nd-Y-Zr-Zn 주조합금의 인장특성에 미치는 시효처리의 영향

김현식,예대희,강민철,김인배,Kim, Hyun-Sik,Ye, Dea-Hee,Kang, Min-Cheol,Kim, In-Bea 한국재료학회 2008 한국재료학회지 Vol.18 No.5

Magnesium alloys are alloyed with rare earth elements (Re, Ca, Sr) due to the limited use of magnesium in high-temperature conditions. In this study, the influences of Zr and Zn on the aging behavior of a Mg-Nd-Y alloy were investigated. magnesium alloys containing R.E elements require aging treatments Specifically, Nd, Y and Zr are commonly used for high-temperature magnesium alloys. Various aging treatments were conducted at temperatures of 200, 250 and $300^{\circ}C$ for 0.5, 1, 3, 6, and 10 hours in order to examine the microstructural changes and mechanical properties at a high temperature ($150^{\circ}C$). Hardness and high-temperature ($150^{\circ}C$) tensile tests were carried out under various aging conditions in order to investigate the effects of an aging treatment on the mechanical properties of a Mg-3.05Nd-2.06Y-1.13Zr-0.34Zn alloy. The maximum hardness was 67Hv; this was achieved after aging at $250^{\circ}C$ for 3 hours. The maximum tensile, yield strength and elongation at $150^{\circ}C$ were 237MPa, 145MPa and 13.6%, respectively, at $250^{\circ}C$ for 3 hours. The strengths of the Mg-3.05Nd-2.06Y-1.13Zr-0.34Zn alloy increased as the aging time increased to 3 hours at $250^{\circ}C$ This is attributed to the precipitation of a Nd-rich phase, a Zr-rich phase and $Mg_3Y_2Zn_3$.

수량화II류를 이용한 산림휴양기능의 평가

김현식,Kim, Hyun-Sik 한국산림과학회 2008 한국산림과학회지 Vol.97 No.4

본 연구는 자연휴양림 내에서 휴양지구를 설정하기 위한 방법을 모색하기 위하여 산림휴양기능의 평가를 시도하였다. 청옥산 자연휴양림을 연구대상지로 선정하고, 표준지 173개 소반을 추출하여 수량화II류를 이용하여 분석하였다. 이때 외적기준은 산림휴양 효용의 정도를 전문가로부터 부여받았고, 설명변수는 기존의 연구결과와 대상지의 산림휴양자원을 고려하여 임상, 임령, 경사, 수변, 도로, 시설의 6인자를 선정하였다. 그 결과, 절대판별적중률은 제 1 2상관비 축에서 각각 82%, 75%로서 예측 가능한 판별 정도(精度)를 얻었다. 요인으로서는 도로와 경사가 산림휴양기능의 잠재력에 큰 영향을 미치고 있으며, 카테고리에 있어서는 도로가 있는 것이, 경사는 낮을수록 산림휴양기능을 높이는 방향으로 작용하는 것을 알 수 있었다. 또한, 청옥산 자연휴양림의 소반별 산림휴양기능의 잠재력을 평가하기 위하여 표준지에서의 예측식을 사용하여 산림휴양효용의 정도를 나타내는 종합점수를 구한 다음, 판별구분점에 의하여 높다(H), 보통(M), 낮다(L)로 3구분하였으며, GIS를 이용하여 분포를 나타내는 평가도를 작성하였다. 수량화라는 형식을 매개로 하여 산림휴양의 효용의 정도에 관한 현실의 직관적 경험적 종합판단을 평가인자와 카테고리가 개입된 분석적 판단으로 변환하고 있는 점에 본 연구의 의의가 있다. This study has intended to evaluate the forest recreation functions to seek methods to designate the recreational areas inside a recreation forest. This study has Mt. Chung-ok in Korea as a study area to which Quantification method II as a valuation measure was applied. This study also has chosen a degree of recreational utility as an external criterion and six factors including Forest type, Forest age, Slope, Riparian area, Road, and Facility for the 173 stands in this area. As a result, absolute discriminated success rate was obtained, so that the first and second estimated correlation ratios were 82% and 74%, respectively. Road and Slope had great influences on the potential power of recreational functions. In the category, recreational function was more influenced by the existence of road and the lower degree of slope. Also, this study has drawn an evaluation map, which displayed the potential power of recreational functions by classifying three discrimination points such as H(High), M(Medium), and L(Low) through calculating the degree of recreational utility of the recreation forest for the stands by applying an estimation formula of recreational function in the stands. This study seems to be worthwhile in terms of actual, experimental, and intuitive interpretation for the degree of recreational utility calculated by using Quantification method theory.

머신러닝 알고리즘을 사용한 웨어러블 스마트 에어백에 관한 연구

김현식,백원철,백운경,Kim, Hyun Sik,Baek, Won Cheol,Baek, Woon Kyung 한국안전학회 2020 한국안전학회지 Vol.35 No.2

Bikers can be subjected to injuries from unexpected accidents even if they wear basic helmets. A properly designed airbag can efficiently protect the critical areas of the human body. This study introduces a wearable smart airbag system using machine learning techniques to protect human neck and shoulders. When a bicycle accident happens, a microprocessor analyzes the biker's motion data to recognize if it is a critical accident by comparing with accident classification models. These models are trained by a variety of possible accidents through machine learning techniques, like k-means and SVM methods. When the microprocessor decides it is a critical accident, it issues an actuation signal for the gas inflater to inflate the airbag. A protype of the wearable smart airbag with the machine learning techniques is developed and its performance is tested using a human dummy mounted on a moving cart.

Midazolam을 이용한 의식진정시 flumazenil의 투여경로에 따른 생징후 및 행동양상의 비교 연구

김현식,이창섭,이상호,Kim, Hyun-Sik,Lee, Chang-Seop,Lee, Sang-Ho 대한소아치과학회 2002 大韓小兒齒科學會誌 Vol.29 No.2

본 연구의 목적은 midazolam을 이용한 의식진정 시 길항제인 flumazenil의 투여경로에 따른 효과와 안전성을 평가하기 위함이다. 연구대상으로는 $22{\sim}24$세의 건강한 15명의 자원자를 이용하였으며, 그들은 midazolam 0.2mg/Kg을 비강내 분무하여 진정하였으며, midazolam 투여 40분 후 길항제인 flumazenil 0.2mg을 정맥 내 투여 및 비강 내 투여하였다. 각 투여경로의 안전성과 효과를 평가하기 위해 다음과 같은 관찰이 실시되었다. 대상의 생징후를 관찰하기 위해 pulse oxymeter(Nellcor symphony N-3000, Nellcor Puritan CO., USA)을 이용하여 $SaO_2$ 및 맥박수를 관찰하였고, 전자혈압계(Heartcare 200, National CO., Japan)을 이용하여 이완기 및 수축기 혈압을 관찰하였다. 또한 실험대상의 주관적 평가를 위해 visual analogue scale(VAS)를 이용하여, 진정, 수면, 피로 그리고 태도에 대해 주관적인 평가를 실시하였다. 모든 대상은 특이할 부작용없이 회복되었다. 연구결과를 요약하면 다음과 같다. 1. 비강내 분무된 flumazenil은 정맥내 투여된 flumazenil에 비해 빠른 회복을 보였으나, 곧이어 정맥내 투여에 비해 깊은 수면상태에 빠졌다. 2. 비강내 투여된 flumazenil 및 정적내 투여된 경우 모두 주의할 부작용 및 생징후의 악화는 관찰되지 않았다. 회복의 목적으로 비강내 분무된 flumazenil의 결과로 미루어 볼 때, midazolam을 이용한 의식진정시 flumazenil의 비강 내 분무를 통해 보다 안전하고, 효과적인 의식진정하 치과치료가 가능하리라 사료된다. 하지만, flumazenil의 적절한 용량 및 효과를 알기위해, midazolam과 flumazenil의 혈장농도를 평가하는 약물동력학적 연구가 계속되어야 하리라 사료된다. The purpose of this study was to evaluate the efficacy and safety depending on the route of flumazenil, as an antagonist against midazolam. The subjects of this study were 15 volunteers of $22{\sim}24$ years old. They were sedated with midazolam 0.2mg/Kg intranasal spray, and then 40 minutes after midazolam administration, they were given flumazenil 0.2mg intranasal spray for their reversal. For evaluation of the efficacy and safety of intranasal spray for flumazenil, they were monitored with pulse-oxymeter(Nellcor symphony N-3000, Nellcor Puritan CO. USA) and electric sphygmomanometer (Heartcare 200, National CO. Japan), and were assessed themselves using visual analogue scale(VAS) for tranquilization, sleep, fatigue and attitude. All of these subjects were reduced completely without any undesired situations. The results from this study can be summarized as follows ; 1. Nasaly administered flumazenil using spray device produced much more rapid reduction than intravenously administered flumazenil, but soon after fell in more deep sedated state than intravenously administered flumazenil. 2. There were no considerable side effects or bad influence on vital signs of both nasaly administered flumazenil and intravenously administered flumazenil. These results suggested that the flumazenil administered nasaly using spray device for reversal, we could treat patients safely and effectively under conscious sedation using midazolam administration. But, We will have to research about its optimal dosages for flumazenil, used as intranasal spray for reversal agents against the midazolam by evaluating the blood plasma concentration of midazolam and flumazenil.

무산소성 뇌증환자의 이소성 골화증에 대한 빈소산 치험례

김현식,김소연,권소연,제준태,윤채성,성강경,Kim, Hyun-Sik,Kim, So-Yeon,Kwon, So-Yeon,Jae, Jun-Tae,Yun, Chae-Sung,Sung, Kang-Kyeng 대한한의학방제학회 2009 大韓韓醫學方劑學會誌 Vol.17 No.2

Heterotopic ossification is often complicated in patients with brain injury. It occurs in the connective tissue of skeletal muscle close to a joint, especially most highly in the hip joint. This study have reported a case of heterotopic ossification in hypoxic brain damage patient due to cardiac attack. Binso-san is known by medication on arthritis. It has an effect on pain control or reduce of swelling in the joints. This study suggest that Binso-san has an improving effect on hip joint affected by Heterotopic ossification.

기동 표적 추적을 위한 퍼지 IMM 알고리즘에 관한 연구

김현식,김진석,황수복,Kim Hyun-Sik,Kim Jin-Soek,Hwang Soo-Bok 한국군사과학기술학회 2004 한국군사과학기술학회지 Vol.7 No.4

The tracking algorithm based on the interacting multiple model(IMM) requires a considerable number of sub-models for the various maneuvering targets in order to have a good performance. But it is not feasible to use the nm algorithm in the real system because of the computational burden. Therefore, we need an algorithm which requires less computing resources while maintaining a good performance. In this paper, we propose a fuzzy interacting multiple model algorithm(FIMMA) for the tracking of maneuvering targets, which uses a minimal number of sub-models by considering the maneuvering properties and adjusts the mode transition probabilities by using the mode probability as a fuzzy input. In order to verify the performance of FIMMA, the developed algorithm is applied to the tracking of i borne targets. Simulation results show that the FIMMA is very effective in the tracking of maneuvering targets.

습식 식각법으로 제조된 박막 인덕터의 임피던스 특성

김현식,송재성,오영우 ( Hyun Sik Kim,Jae Sung Song,Young Woo Oh ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.8