무선 통신을 이용한 열차운행 제어 방식에 대한 연구

임재식(Lim jae-sik),김치조(Kim chi-jo),강만식(Kang man-sik) 한국철도학회 2003 한국철도학회 학술발표대회논문집 Vol.- No.-

Train control by radio based communication is one of the interesting new fields in train signal. The radio based control has more benefits, low headway and low construction and maintenance cost, than conventional control. In this paper, a safe and efficient train operation is introduced. Triple radio communications, train to train, train to station, and train to central traffic control, are used to increase the reliability. One of these communications channels has a fault; the others can take the functions of it. Absolute position of a train is transmitted to station via radio communication. In the station, the interlocking mechanism should be activated as the legacy.

Invariant Set Based Model Predictive Control of a Three-Phase Inverter System

임재식(Jae Sik Lim),박효성(Hyo Seong Park),이영일(Young Il Lee) 제어로봇시스템학회 2012 제어·로봇·시스템학회 논문지 Vol.18 No.2

This paper provides an efficient model predictive control for the output voltage control of three-phase inverter system which includes output LC filters. Use of SVPWM (Space Vector Pulse-Width-Modulation) and the rotating d-q frame is made to obtain an input constrained dynamic model of the inverter system. From the measured/estimated output current and reference output voltage, corresponding equilibrium values of the inductor current and the control input are computed. Derivation of a feasible and invariant set around the equilibrium state is made and then a receding horizon strategy which steers the current state deep into the invariant set is proposed. In order to remove offset error, use of disturbance observer is made in the form of state estimator. The efficacy of the proposed method is verified through simulations.

증분형 엔코더를 이용한 로봇 관절의 절대위치 검출

임재식(Jae Sik Lim),이영진(Young Jin Lee) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.6

This paper proposes an efficient detection of absolute position of a robot joint using two incremental encoders. We considers a robot joint comprising a motor, a reducer, two encoders, and a motor drive. An incremental(first) encoder provides motor’s rotor position or input position of reducer while another incremental(second) encoder does output position of the reducer. A table is made where the relationship between the first and the second encoder counts is recorded. The key point is placed where the table is constructed: when a pulse occurs in the second encoder, there exists a corresponding unique count value of the first encoder. The absolute position is detected using the table by searching the second encoder position corresponding to the first encoder count value when a pulse occurs in the second encoder. The proposed method needs a small rotation, as just one second encoder"s pulse angle, for the initial absolute position detection.

일반촬영 검사 시 Wireless digital radiography(DR) detector 사용에 따른 설문과 재질에 따른 detector case 비교

정재화(Jae-Hwa Jeong),정지상(Ji-Sang Jeong),안치복(Chi-Bok Ahn),김성식(Sung-Sik Kim):박순규(Sun-Kyu Park),임재식(Jae-Sik Lim) 대한영상의학기술학회 2017 대한영상의학기술학회 논문지 Vol.2017 No.1

목 적:Mobile DR detector를 사용함에 있어서, 고가의 detector를 파손과 침수로부터 보호하고 감약과 재촬영을 최소화하여 환자의 안전성을 높이기 위한 설문으로서 현 대학병원의 실태를 보고함에 있다. 대상 및 방법:2017 년 1 월 전국대학병원 일반촬영실 방사선사를 대상으로 실태조사를 하였다. 성별과 연차 별로 Computed Radiography (CR)에서 Digital Radiography (DR)로 변화함에 따라 검사방법의 차이점과 재촬영율의 변화를 설문하였고, Detector case의 필요성과 발전방향에 대해 조사하였다. Plastic, Silicon, Carbon Detector 케이스의 X-선 속 감약 측정은 디지털 진단용 엑스선 촬영장치인 DK medical innovision X-ray 장비를 사용하여 70 kVp, 5 mAs, 10 by 10 cm ROI 조건으로 10 cm acryl phantom을 투과한 량을 Patient Skin Dosimeter (PSD) 로 측정하였다. 결 과:실태 조사한 전체 설문 작성자의 60%가 CR에서 DR로 변화하며 재촬영율이 0~5퍼센트 가량 증가하였다고 응답하였으며 재촬영 증가의 이유는 간단한 재촬영과 무거워진 detector의 영향으로 나타났다. DR detector case가 필요하다고 응답한 경우는 93.3%이며 case의 필요조건은 무게, 방수, 견고 순으로 조사되었다. 새로운 case의 선호 재료는 silicon 혹은 고무가 가장 높게 조사되었고 감염방지와 방수를 위해 비닐커버는 93.3%가 필요하다고 응답하였다. PSD 측정 결과 X-선속은 2 mm plastic이 18.3 μGy, 1 mm carbon은 19.32 μGy, 2 mm silicon은 18.95 μGy 케이스가 없을 경우는 19.37 μGy로 case를 씌우지 않았을 경우와 Plastic 2 mm case의 X-선속 감약 차이는 약 5% 가량으로 측정되었다. 결 론:Mobile Detector 는 응급상황에서 빠르게 검사하고 영상을 확인하여 신속한 환자 진료에 도움을 주지만 고가의 장비인 만큼 방사선 종사자의 각별한 주의가 필요하다. 실태조사한 대학병원의 약 80%가 detector 가 파손과 침수 경험이 있다고 한 만큼 사고를 줄이기 위한 노력이 꾸준히 필요하며 새로운 case가 반드시 필요하다고 할 수 있다. 본 연구의 목적과 같이 불필요한 감약은 최소한으로 줄이고, 환자의 안전성을 높이는 고민을 꾸준히 해야 할 것이다. Purpose:The purpose of this study is to show the situations of university hospital using questionnaire, which is about protecting expensive x-ray detector from damage and flooding, and reducing attenuation and reexamination to improve patient safety in chest x-ray exam with mobile e Digital Radiography (DR) detector. Materials and Methods:We conducted survey of radiographers general x-ray department in university hospital on January in 2017. As CR system has been changing into DR system, We carried out a survey of differences of exam methods and re-taking rate along gender and work experiences to prove necessity of detector case. Innovision is used as a diagnostic x-ray system of DK medical. The parameter was 70 kVp, 5 mAs, ROI was set as 10*10 cm. Attenuation of x-ray for the case mode of plastic, silicon and carbon is measured by PSD from penetration of 10 cm acryl phantom. Result:60% of respondents of this survey answered tat re-taking rate has been by 5%, while CR system has been chaging into DR system as a result form heavy detector and easy re-taking. 93.3% respond tat DR case is needed and required light-weight, water proof, and firmness. Silicon and rubber is preferred the most as material of the case. 93.3% of respondents answered that vinyl cover is needed for prevention of infection and waterproof. As result of PSD measurement, X-ray dose was 183 μGy for 2 mm plastic, 19.32 μGy for 1 mm carbon, 18.95 μdGy for 2 mm silicon, 19.37 μGy without detector case. The difference between detector with case and without case was around 5%. Conclusion:Mobile detector is convenient in emergent situation to exam and verify images quickly, while radiographers should be cautions of its high-prices. Moreover, over 80% of targeted hospital have experiences of broken and flooding damage on detector. therefore, it is considered that DR detector case in indispensable to reduce attenuation and improve patient safety

관수로시스템의 유속계수 추정기법에 관한 연구

김영화,임재식,박영진,Kim Young-hwa,Lim Jae-sik,Park Young-jin 한국관개배수위원회 1996 한국관개배수논문집 Vol.3 No.2

To make a real hydraulic simulation model, Hazen-Williams' coefficient must be calibrated using the measured discharges and hydraulic head loss. In this paper, calibrating method of Hazen-Williams' coefficient was proposed for pipeline system. The calibra

64 Channel Coronary Angio CT에 있어서 조영제와 Saline의 Bi-phase Injection과 재구성방법에 관한 연구

김홍식(Hong Sik Kim),최진혁(Jin Hyuck Choi),강성호(Sung Ho Kang),홍완기(Wan Ki Hong),임재식(Jae Sik Lim) 대한CT영상기술학회 2006 대한CT영상기술학회지 Vol.8 No.1

Globalization has brought changes in many areas of Korean society. In the past 10 years, cancer and other geriatric diseases among Koreans have been radically growing, possibly resulting from dietary changes and lack of exercise. Among the growing number of geriatric patients, those with circulatory diseases(cardiovascular and cerebrovascular diseases) are consistently growing. Cardiovascular diseases include not only ailment of cardiovascular organs, but also various symptoms resulting from cardiovascular malfunctions, such as hypertension, angina, myocardial infarction, and strokes. Since cardiovascular diseases are correlated with many other geriatric symptoms, they should be researched more seriously on the ground of promoting national health and well-being.

Standing L-spine AP 검사에서 Single Grid와 Multi Grid의 선량 변화 및 영상의 화질 평가

채경식(Kyung-Sik Chae),박남이(Nam-Yee Park),진덕은(Duk-Eun Jin),임재식(Jae-Sik Lim),강성호(Sung-Ho Kang) 대한영상의학기술학회 2012 대한영상의학기술학회 논문지 Vol.2012 No.-

목적: Single grid와 multi grid를 각각 사용한 L-spine standing AP 검사에서 표면선량과 유효선량 및 영상의 화질을 비교 평가하여 single grid에 비교한 multi grid의 유용성을 평가하고자 하였다. 대상 및 방법: X-선 발생장치는 GE사의 DEFINIUM 8000을 사용하였다. 복부 phantom을 이용하여 MITAYA사의 MS X-RAY GRID 100cm single grid와 130cm mid range grid(multi grid)를 각각 Source to Image Distance (SID) 100cm에서 부터 10cm 간격으로 180cm까지 80 kV, 500 mA, 100msec, 50 mAs, 조사야 크기 16X16 조건으로 10회씩 exposure 하였다. Unfors Patient Skin Dosimeter (PSD) 선량계를 이용하여 표면선량을 측정하고 그 유효선량 값을 구하였다. 영상의 진단적 가치 평가로는 영상의 물리적 특성의 변화를 감지하는 Peak Signal to Noise Ratio(PSNR)측정의 방법을 통해 객관적 평가를 실시하였다. 결과: 실험 결과 SID가 증가하면서 두 종류의 grid 모두 표면선량과 유효선량이 감소하였 다. 특히 single grid보다 multi grid를 사용하여 실험 측정 하였을 때 각 구간에서의 표면 선량 값이 평균 2.7% 더 낮게 측정되었다. 표면선량을 바탕으로 계산하여 얻은 유효선량 또한 SID가 증가할수록 감소 한다는 사실을 알 수 있었다. 객관적 평가를 실시 하고자 얻은 PSNR 값은 single grid를 사용하였을 때, SID 110cm 부터 150cm 까지 30 dB 이상이었 으나, SID 160cm 이상부터는 30 dB 이하로 측정 되었다. 이에 반해 multi grid를 이용하여 얻은 영상은 SID 110cm부터 180cm까지 모두 30dB 이상으로 측정되었다. 결론: 검사 종류와 빈도가 많은 일반촬영 검사에서 각 검사마다 실시하는 grid 교체 문제는 검사의 빠른 진행에 있어서 중요한 요소이다. 본 연구에서는 single grid에 비해 촬영 거리가 100cm에서부터 180cm까지 비교적 제한이 적은 multi grid를 사용하여 진단적 가치는 동일한 영상을 획득하면서 환자 피폭을 감소 시킬 수 있는 사실을 확인할 수 있었으며, 검사 시간 단축을 통해 대기시간을 상당 부분 감소시킬 수 있게 되어 standing L-spine AP 검사시 유용한 방법이라 생각된다. rface dose, effective dose and image quality of L-spine AP examination used single and multi grid each. Materials and Methods: X-ray unit was used for GE s DEFINIUM 8000. We using the phantom s abdomen MITAYA MS X-RAY GRID 100cm single grid and 130cm mid range grid (multi grid), respectively, source to image distance (SID) 100cm to 180cm from the 10cm intervals 80 kV, 500 mA, 100msec, 50 mAs, field size, the size (16X16) conditions, exposure times were 10. Unfors Patient Skin Dosimeter (PSD) dosimeter to measure the surface dose and effective dose values that were obtained. We used single and multi grid each. We evaluated value of image diagnosis with Peak Signal to Noise Ratio (PSNR) measurement which detects a variation of image physical specific. Results: According to increase of SID, both surface dose and effective dose decreased with single grid and multi grid both. Especially surface dose using multi grid at each section is measured average 2.7% lower than single grid. It is same to effective dose which is calculated from surface dose. The PSNR value with single grid is measured 30 dB over at SID from 110cm to 150cm, but 30 dB under at SID 160cm over. Generally the image of 30 dB under PSNR value is not proper to diagnosis. Because 30 dB under PSNR value indicate image quality lowering. Comparatively the PSNR value with multi grid is measured 30 dB over at SID from 110cm to 180cm. Conclusion: It is an important factor grid replacement problem in flat examination. Because flat examination has a large number of examination variety and frequency. This study can confirm the fact that multi grid examination lower limited SID from 100cm to 180cm can reduce patient s dose with acquiring same image about diagnostic value. Besides it can reduce waiting time through reducing examination ime, so multi grid examination is regarded to useful method in L-spine standing AP examination compared with single grid examination.

극 배치 기법을 이용한 표면 부착형 영구자석 동기 전동기의 고속 토크 제어

박효성(Hyo-Seong Park),임재식(Jae-Sik Lim),한정호(Jung-ho Han),송중호(Joong-Ho Song),이영일(Young-Il Lee) 제어로봇시스템학회 2013 제어·로봇·시스템학회 논문지 Vol.19 No.12

In this paper we propose a novel torque control method for permanent magnet synchronous motors using the SVPWM (Space Vector PWM). The control law is described in the rotating d-q frame and is devised to track a given reference flux with which the reference torque is generated. The key feature of the proposed control is that it provides uniform dynamics with desired closed-loop poles independent of the rotating speed and the desired poles can be selected to yield a fast response with only a small amount of torque ripple.

지뢰 탐지시스템의 구동장치 제어 연구

박민수(Minsu Park),임재식(Jae-Sik Lim),김민수(Minsu Kim),김상욱(Sanguk Kim),최종성(Jongsung Choi),송정일(Jungil Song) 한국해군과학기술학회 2023 Journal of the KNST Vol.6 No.1

관전압 제어 software의 Automatic 과 semi-Automatic 기능에 관한 연구

이혜진(Hye Jin Lee),김홍식(Hong Sik Kim),임기빈(Ki Bin Lim),강성호(Sung Ho Kang),임재식(Jae Sik Lim) 대한CT영상기술학회 2014 대한CT영상기술학회지 Vol.16 No.2

Purpose : When using Automatic Tube Voltage Selection (ATVS), the comparative analysis of the phantom study by the quality of the images and dose at each step of automatic and semi-automatic functions, will be examined for differences Materials and methods : The sample mixed with contrast medium and saline is positioned between the thorax and abdomen phantom so that HU (Hounsfield unit), Noise and SNR can be measured by changing the set value of Ref. kV in the 1, 3, 5, 7, 9, 11 stages with the following cases whether the automatic and semi-automatic functions in ATCM and ATVS are used or not. After Phantom scanning for dosimetry, the value of CTDIDLP(dose length production) displayed on the device was used to measure it. Result : Noise was increased in stages from the group using the Automatic ATVS and ATCM. It was similar to the distributions measured value of 100kVp after using 120 ref. kV setting and 100kVp, 120kVp after use when it was set 140 ref. kV in group using Semi-automatic. In the value of HU and SNR, all groups showed different distributions. In the group using the Automatic ATVS and ATCM, doses were reduced as the level increases. In the group using Semi-automatic ATVS, doses were decreased at 100kVp after using 120 ref. kV setting and 100kVp, 120kVp after it was set to 140 ref. kV. Conclusion : In terms of using ATVS software, a more cautious approach is needed in order to obtain the quality of images and dose-reduction effects, that the inspector had expected. Also, changing the value of Ref. kV setting and the function of a Semi-automatic have to be considered to use cautiously. 목적 : 관전압의 제어(Automatic tube voltage selection, 이하 ATVS)사용에 있어 Automatic 과 semi-Automatic 기능의 단계 별 선량과 영상의 질을 팬텀 연구를 통해 비교분석 하여 그 차이에 대해 알아보고자 한다. 대상 및 방법 : 조영제와 saline을 혼합한 Sample을 흉부와 복부 phantom사이에 위치시켜 관전류제어(Automatic tube current modulation,이하 ATCM)와 ATVS를 사용하지 않았을 때와 ATCM와 ATVS의 Automatic과 semi-Automatic 기능을 사용한 1, 3, 5, 7, 9, 11 단계에서 Ref. kV 설정값을 변화하여 HU(Hounsfield unit), Noise, SNR을 측정하였다. 선량 측정을 위하여 Phantom scan 후 장비에 표시된 CTDIDLP(dose length production) 값을 이용하여 측정하였다. 결과 : Nois는 Automatic ATVS와 ATCM을 사용한 그룹에서 단계별로 차츰 높아졌는데 이와 비슷한 분포는 Semi-Automatic ATVS를 사용한 그룹에서 120 ref. kV설정 시 100 kVp사용 후와 140 ref. kV 설정 시는 100kVp, 120kVp사용 후 측정치의 분포였다. HU값과 SNR은 모든 그룹이 Automatic ATVS와 ATCM을 사용한 그룹과 다른 분포를 보였다. 선량은 Automatic ATVS와 ATCM을 사용한 그룹은 단계가 높을수록 선량이 감소하였으며 Semi-Automatic ATVS를 사용한 그룹에서 120 ref. kV설정 시 100 kVp사용 후와 140 ref. kV 설정 시는 100kVp, 120kVp사용 후 단계별 선량이 감소하였다. 결론 : ATVS 사용시 검사자가 기대했던 영상의 질과 선량감소 효과를 얻기 위해선 보다 신중한 접근이 필요하며 Ref. kV 설정값의 변경과 Semi-Automatic 기능은 주의 깊게 사용해야 될 것으로 사료된다.