멀티미디어 기법을 이용한 의학교육자료의 제작 및 재생 시스템

차은종(Eun Jong Cha),이태수(Tae Soo Lee),황영일(Young Il Hwang),구용숙(Yong Sook Goo),이현무(Hyun Moo Lee),김원재(Wun Jae Kim) 한국의학교육학회 1994 Korean journal of medical education Vol.6 No.1

Medical education and research require various forms of information, which form multimedia data. While traditional computer can only deal with numeric and coded data, modern computer technology enabl es intergrated management of multimedia data. The present system was designed to perform convenient, acquisition, processing and analysis, and efficient presentation of medical multimedia data. APC-486 DX2 system epuipped with 8MB DRAM and 250 MB HDD provided fast enough computation speed, and image quality guaranteed by 17-inch SVGA color monitor. Both sound and image data are simultaneously acquired through a condenser microphone and audiocard, and respectively, in a video signal format. Printed pictures are digitized by a color scanner. Data transmission is also possible through a local area network (LAN). Acquired media data are structured in a hierarchy with the image data as apex. A variety of image processing and analysis algorithms were implemented and the media data can be reproduced simultaneously. Furthermore, simple and dynamic image animation can be performed to enhance data editing and authoring capability. Selected data sets can be reproduced in a user defined sequence, enabling multimedia slide presentation . User interface was made in Windows format and all application programs were written in Borland C++ for future flexibility and extension. The present system will be of convenient use to acquire, manage, and present multimedia data for medical education and research.

속도계측형 호흡기류센서에서 상승시간을 고려한 최고호기유량의 교정 기법

차은종(Eun-Jong Cha),이인광(In-Kwang Lee),김성식(Seong-Sik Kim),김완석(Wan-Suk Kim),박경순(Kyung-Soon Park),김원재(Wun-Jae Kim),김경아(Kyung-Ah Kim) 대한전기학회 2009 전기학회논문지 Vol.58 No.4

Peak expiratory flow rate(PEF) is one of the most important diagnostic parameters in spirometry. PEF occurs in a very short duration during the forced expiratory maneuver, which could lead to measurement error due to non-ideal dynamic characteristic of the transducer. In such case the initial slope of the flow rate signal determines the accuracy of the measured PEF. The present study considered this initial slope as a parameter to compensate PEF. The 26 standard flow rate signals recommended by the American Thoracic Society(ATS) were flown through the air flow transducer followed by simultaneous measurements of PEF and maximum transducer output(NPEF). NPEF-PEF satisfied a quadratic equation in general, however, two signals(ATS #2 and #26) having large initial slopes deviated from the fitting equation to a significant degree. The relative error was found to be in a linear relationship with the initial slope, thus, NPEF was appropriately compensated to provide accurate PEF with mean relative error less than only 1%. The 99% confidence interval of the mean relative error was less than a half of the error limit of 5% recommended by ATS. Therefore, PEF can be very accurately determined by compensating the transducer output based on the initial slope, which should be a useful technique for air flow transducer calibration.

전자제어 밸브용 통합 개발 장치 설계 및 구현

차은종(CHA Eun Jong),김태호(KIM Tae Ho),박찬식(PARK Chansik) 한국통신학회 2015 한국통신학회 학술대회논문집 Vol.2015 No.1

노력성 폐활량검사시 호흡기류센서의 보정기법

차은종(Cha, Eun-Jong),이인광(Lee, In-Kwang),장종찬(Jang, Jong-Chan),김성식(Kim, Sung-Shick),이수옥(Lee, Su-Ok),정재관(Jung, Jae-Kwan),박경순(Park, Kyung-Soon),김경아(Kim, Kyung-Ah) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.5

노력성 폐활량(FVC) 검사시 호식기류의 최대값인 최고호기유량(PEF)은 호흡기능의 평가에 매우 중요하게 활용되는 진단 매개변수이다. PEF는 검사 초기에 매우 짧은 순간에 크게 증가하는 양상을 띠기 때문에 호흡기류센서의 동특성이 충분하지 않은 경우 측정오차가 발생한다. 본 연구에서는 노력성 호식기류 상의 초기 상승속도 (Sr)를 산출하고 Sr 값에 기초하여 센서 출력값을 보정하는 새로운 기법을 제안하였다. 미국 흉부학회(ATS)에서 제공하는 표준 기류신호 파형 26개를 생성하여(F) 속도계측형 호흡기류센서로 통과시키며 센서 출력신호(N)를 축적하였다. F의 최대값인 PEF와 N의 최대 값인 NPEF 간에는 당초 예상했던 대로 2차함수 관계가 성립하였으나(상관계수 0.9997), ATS파형 #2 및 26은 상당한 이탈을 보였다(상대오차>10%). NPEF의 상대오차와 Sr 간의 관계를 분석하여 상호 선형적인 관계를 얻었으므로, 이를 이용하여 보정한 결과 PEF 상대오차의 99% 신뢰구간이 약 2.5% 이었다. 이는 국제 표준인 ATS의 오차한계인 10%의 1/4 이내로써 매우 정확한 보정이 이루어졌다. 따라서 본 연구에서 제안하는 보정기법은 호흡기류센서 교정시 매우 유용하리라 판단된다. Peak expiratory flow rate(PEF) is a very important diagnostic parameter obtained from the forced vital capacity(FVC) test. The expiratory flow rate increases during the short initial time period and may cause measurement error in PEF particularly due to non-ideal dynamic characteristic of the transducer. The present study evaluated the initial rise slope(Sr) on the flow rate signal to compensate the transducer output data. The 26 standard signals recommended by the American Thoracic Society(ATS) were generated and flown through the velocity-type respiratory air flow transducer with simultaneously acquiring the transducer output signal. Most PEF and the corresponding output(NPEF) were well fitted into a quadratic equation with a high enough correlation coefficient of 0.9997. But only two(ATS#2 and 26) signals resulted significant deviation of NPEF with relative errors>10%. The relationship between the relative error in NPEF and Sr was found to be linear, based on which NPEF data were compensated. As a result, the 99% confidence interval of PEF error was turned out to be approximately 2.5%, which was less than a quarter of the upper limit of 10% recommended by ATS. Therefore, the present compensation technique was proved to be very accurate, complying the international standards of ATS, which would be useful to calibrate respiratory air flow transducers.

무선 요속계 시스템 구현

차은종(Eun-Jong Cha),최성수(Seong-Su Choi),이인광(In-Kwang Lee),김도경(Do-Kyung Kim),한순화(Soon-Wha Han),김경아(Kyung-Ah Kim) 대한전기학회 2010 전기학회논문지 Vol.59 No.12

Benign prostatic hyperplasia (BPH) significantly deteriorates the quality of life in aged men. Uroflowmetry is a convenient non-invasive clinical test to diagnose BPH. However, the test is usually performed in the presence of a technician, which may affect the way of urination for the lack of privacy. The present study developed a wireless uroflowmeter to provide the best privacy with a user program on PC evaluating the diagnostic parameters. Pilot experiment was followed to test clinical applicability.

가정용 무선 호흡기류 및 요속신호 계측 시스템 개발

차은종(Eun-Jong Cha),이인광(In-Kwang Lee),이유미(You-Mi Lee),한순화(Soon-Wha Han),한정수(Jeong-Su Han),서재원(Jae-Won Suh),박찬식(Chan-Sik Park),김경아(Kyung-Ah Kim) 대한전기학회 2012 전기학회논문지 Vol.61 No.9

Medical system for personal health management recently changes its paradigm from hospital service to self home care based on ubiquitous technology for healthcare anywhere at any time. The present study developed a wireless bio-signal measurement system for patients to self manage pulmonary disease and benign prostate hyperplasia(BPH), both of which are chronic diseases with increasing frequency in modern society. Velocity-type respiratory air flow transducer adapted to develop respiratory module for pulmonary disease management was simplified in structure to measure uni-directional flow since most important diagnostic parameters are evaluated on the expiratory flow signal only. Standard weight measurement technique was introduced to obtain urinary flow signal for BPH management. Three load cell signals were acquired for averaging to minimize noise, followed by accuracy evaluation. Transmission and receiver modules were also developed with user program for wireless communication. Averaged relative errors were 2.05 and 1.02% for respiratory volume and maximal flow rate, respectively, and the relative error was 2.17% for urinary volume, demonstrating that both modules enabled very accurate measurements. Wireless communication distance was verified within 15m, long enough for home care application. The present system allows the user to select a necessary measurement module on a particular health demand and to immediately provide the self-test results, thus better quality health care would be possible.

척추경 나사못의 디자인이 고정력 및 구동 토크에 미치는 영향 분석: 이중 나사 및 이중 피치 나사

최선각,차은종,김경아,안윤호,Choi, Sun-Gak,Cha, Eun-Jong,Kim, Kyung-Ah,Ahn, Yoon-Ho 대한의용생체공학회 2018 의공학회지 Vol.39 No.3

One of the most common problems with pedicle screw system is pullout of the screw. This study was performed to evaluate the pullout strength and driving torque of newly designed pedicle screws. The design of three type screws were standard pedicle screw, which had single lead threaded and single pitched design (Type A), single pitched and dual lead threaded pedicle screw (Type B), dual pitched and dual lead threaded pedicle screw (Type C), respectively. The tests were performed in accordance with the ASTM standards using polyurethane (PU) foam blocks. There was no significant difference in pullout strength among three types of screw. Type B and Type C exhibited higher insertion torque and removal torque than Type A, respectively (p<0.05). Pedicle screws newly developed with dual pitched and dual lead threaded design showed higher driving torque without decrease in pullout strength compared to the standard pedicle screw and could be inserted more rapidly with the same number of revolutions.

CDMA망 기반 3채널 심전도 모니터링 시스템의 평가

홍주현,차은종,이태수,Hong, Joo-Hyun,Cha, Eun-Jong,Lee, Tae-Soo 대한의용생체공학회 2008 의공학회지 Vol.29 No.4

A wireless 3 channel ECG monitoring system was developed so that it could monitor the health and movement state during subject's daily life. The developed system consists of a wireless biomedical signal acquisition device, a personal healthcare server, and a remote medical server. Three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and commercial reference device during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during five types of motion in daily life, the accuracy of data transmission to remote server using CDMA network was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. In addition, PDA-phone based wireless system enabled subject to be monitored without any constraints. Therefore, the developed system is expected to be applicable for monitoring the aged and chronic diseased people and giving first-aid in emergency.

에러그리드를 사용한 대체부위 혈당검사의 유용성 검증

박경순,차은종,Park, Kyung-Soon,Cha, Eun-Jong 대한의용생체공학회 2011 의공학회지 Vol.32 No.1

Blood glucose information is important for self regulation in daily life, but the frequency of self test remains to be only 17%(9 tests/month) in Korea, mainly due to pain during blood sampling. The present study tried to validate the clinical efficacy of the forearm as an alternative sampling site with minimized pain. Capillary blood was sampled both on the index finger($G_F$) and the forearm($G_A$), immediately followed by glucose measurements in 531 subjects, 25 who visited the Health Enhancement Center of C University Hospital, then venous blood($G_V$) was sampled for glucose test. The blood glucose concentration measured on the forearm was closer to the venous glucose than on the finger. The mean difference between $G_V$and $G_F$ was only 10 mg/dL well within the internationally accepted error limit. Error grid analyses of $G_F-G_V$, $G_A-G_V$ and $G_A-G_F$ revealed that the number of data points in regions A and B took 100%, 99.8%, and 97.9%, respectively. These results demonstrate the forearm blood glucose test is not only accurate but also clinically valid. Therefore, the forearm blood glucose test can be a useful way of self managing the chronic diabetes with minimized sampling pain.

음영분석에 의한 내시경 영상의 3차원 형체 추정에 관한 연구

이태수,차은종,윤세진,Lee, Tae-Su,Cha, Eun-Jong,Yun, Se-Jin 대한의용생체공학회 1995 의공학회지 Vol.16 No.4

위내시경 영상의 음영을 분석하여 내부 벽면의 3차원적인 형체를 추정하는 새로운 기법을 제안하였다. 이를 위해 우선 내시경의 기기적인 특성을 분석한 다음, 진단 대상이 되는 위벽면 자체의 특성으로 인해 내시경 영상의 특성을 분석하였다. 이를 사전정보로 하고, Horn의 변분법을 도입하여 반복적인 음영분석 알고리즘을 구현하였다. 알고리즘의 타당성 여부를 증명하기 위하여 위모형에서 획득한 $512{\times}512$ 영상 중에서 $256{\times}320$을 대상으로 해서, 시뮬레이션을 수행하였다. 이때 Lagraniginan multiplier의 값이 0.3일 경우 알고리즘의 수렴성 및 전체오차 특성이 가장 좋았으며, 가장 정확한 위벽면의 재구성이 이루어짐을 보였다. A new numerical method estimated three dimensional shape of the internal surface of the stomach by analyzing the shading data of endoscopic image. First analyzed was the inherent instrumentational characteristics of the endoscope system, followed by the analysis of the stomach surface properties, both of which affected the imaging properties. We employed these prior informations to implement the iterative algorithm of shading analysis based on Hom's variational approach. The present algorithm was validated by performing simulation on a $256{\times}320$ image data chosen from original $512{\times}512$ image of the stomach surface model. The best 3-dimensional estimation of the surface was achieved with the Lagrangian multiplier, of 0.3, when the algorithm best converged showing minimal estimation error.