그리드지도의 방향확률을 이용한 직선선분의 추출

강승균,임종환,강철웅 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.1

The paper presents an efficient method for extracting the line segments in a local map of a robot's surroundings. The local map is composed of 2-D grids that have both the occupancy and orientation probabilities from sonar information. To find the shape of an object in a local map from orientation information, the orientations are clustered into several groups according to their values. The line segment is ,then, extracted from the clusters based on Hough transform. The proposed technique is illustrated by experiments in an indoor environment.

생쥐 2-세포기 수정란의 초급속동결

강만종,이철상,한용만,유대열,이경광 제주대학교 농과대학 제주도축산문제연구소 1991 畜産論叢 Vol.6 No.1

This study was carried out in order to investigate eggects of cryoprotectant concentration and equilibration time on survival of ultrarapidly frozen 2-cell mouse embryos Mouse 2-cell embryos. fol-lowing dehydration by exposure to DMSO and sucrose. were directly immersed into liquid nitrogen and thawed in 37℃ water. Viability was defined by development rate to the blastocyst stage after in vitro culture for 72 hours. The results are summarized as follows ; 1. When 0.25M of sucrose was added into the freezing medium a t various concentrations of DMSO and dilution medium, higher development rate of embryo was obtained in 3.0M DMSO conentrations (82.6%). However, When sucrose concentrations of 0.25 and 0.5M were added to the freezing medium with 3.0M DMSO and dilution medium, development rate of embryos were 81.7% and 24.1%, respectively. 2. In the equilibration time at room temperature, higher development rate was attained after short period of time(2.5min) in 3.0M DMSO +0.25M sucrose(85.9%). 3. The development rate of embryos at in vitro 2-celL in vivo 2-celL solution control and untreated control was 84.6%, 90.9%, 89.9%. and 89.7%. respectively.

풍력발전기의 설비이용률 계산을 위한 확률밀도함수의 비교

강택근,허종철,좌종근 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.1

The Weibull probability density function and the Rayleigh function are compared by analyzing the capacity factors which are computed using the probability density functions with different mean wind speeds. For this analysis, the wind speed means of arithmetic, root mean square, cubic mean cuberoot, and standard deviations are computed from the measured wind speed data of a specific site, and the coefficients of probability density functions are calculated. The capacity factors for Vestas 850[kW] wind turbine are calculated and analyzed. The results show that the wind speed frequency curve by Rayleigh function is more close to the actual curve than by Weibull function. The more the wind speed frequency curve is close to the actual one, the more the capacity factors become large values.

말기신부전 환자에서 혈액투석 전후의 QT간격분산 비교

강대웅,정지용,윤나라,안치용,김종오,신병철,정종훈,김현리 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.2

Background: Some cases of QT interval, corrected QT interval (QTc), QT dispersion (QTd) and corrected QT dispersion (QTcd) have been reported in ESRD, but these results are variable and the influence of a hemodialysis is still controversial, In this study, we investigated the effect of hemodialysis on QT and QTc interval and QT and QTc dispersion in patients with ESRD 15 min before and 15 minute after each hemodialysis. Methods: Sixty-seven patients with ESRD (men 33 & women 34) on three-times stable hemodialysis (>3 months) were randomly enrolled. Fifty control subjects with a similar age and normal renal function were enrolled from this hospital. Routine biochemical studies were measured pre- and post dialysis, at the time of the ECG. Plasma Na+, K+, BUN, creatinine, ionized calcium and phosphate were checked. Twelve-lead electrocardiographs were performed at 10㎜/mv and 50㎜/s using a HewIett-Packard Pagewriter 100, before and after a single hemodialysis session.The QT interval was measured from the onset of the QRS complex to the end of the T wave. If the end of the T wave was not clear in a particular lead then it was excluded from analysis. When U waves were present, the end of the T wave was taken as the nadir between the T and U waves. Each QT interval was corrected for heart rate using Bazett's formula (QTc==QT/√(RR)) (ms). The difference between maximal and minimal QT interval duration was defined as QT dispersion (QTd) in each of the 12 leads. Result: This study demonstrates that QT, QTd, QTcd is higher in hemodialysis patients compared with control subjects, and QT and QTd rise postdialysis to levels comparable to those seen acutely following myocardial infarction, when patients are at greatly increased risk of potentially fatal ventricular arrhythmias, Conclusions: QT interval and QT dispersion, markers of risk for arrhythmias and sudden death, are elevated in hemodialysis patients, and rise postdialysis. QT interval and QT dispersion is an easily obtainable, noninvasive, simple, inexpensive, and widely available method of risk stratification in uremic patients receiving chronic dialysis. Additional studies are needed to clarity whether increased postdialysis QT dispersion results in an increased occurrence of arrhythmias.

CFD를 이용한 광촉매 정수장치모듈의 최적구조 국문제목

강한용,최병철,김종호 한국공업화학회 2004 응용화학 Vol.8 No.1

The flow fields inside the photo-catalytic module for water treatment system were studied. The fluid flow inside the module was visualized mainly by CFD (computer fluid dynamics) analysis, and the numerical analysis was authorized by PIV(particle image velocimetry) measurement. The flow patterns in the module for 3 types of innards and 6 kinds of flow rate were analyzed by CFD. Model 1 had better performance below 0.1 L/s of the flow rate, and model 2 over 0.2 L/s of the flow rate with the homogeneous flow field innards of photo-catalytic module.

HPLC-ECD를 이용한 흰쥐 뇌의 선조체 중 신경전달물질의 동시분석시 최적 조건

강종성,문민선,신형선,이순철 충남대학교 약학대학 의약품개발연구소 1995 藥學論文集 Vol.11 No.-

흰쥐 뇌의 선조체로부터 catecholamine, indoleamine 및 대사산물을 동시분석할 수 있는 간편한 방법을 제시하였다. 기기는 ECD를 장착한 HPCL를 사용하였고, 고정상인 C_18 컬럼에서, 이동상은 10mM citric acid, 0.13mM Na_4EDTA, 0.58mM SOS를 함유하는 35mM sodium acetate buffer(pH 3.4) : MeOH=85:15가 최적이었다. 이 때 컬럼온도는 30℃였다. 이 조건으로 dopamine(DA), 3, 4 -dihydroxyphenyl acetic acid(DOPAC), homovanilic acid(HVA), 5-hydroxyindole acetic acid(5-HIAA), serotonin(5-HT) 및 noradrenaline(NA)을 미량까지 분석할 수 있었고, 검출한계는 각 성분에 대해 1회 주입당 2~10pg이었다. 이 방법으로 흰쥐의 주령 및 성별에 따른 선조체내 생체아민과 대사산물의 함량을 비교하였다. 7주령 쥐에서 암컷은 수컷보다 DA와 5-HT의 함량이 유의성 있게 높은 것으로 나타났으며, 주령이 증가함에 따라 암컷에서 DOPAC의 함량이 유의적으로 증가하였다. A simple, efficient and sensitive method was described for the simultaneous determination of catecholamine, indoleamine and related metabolites from the homogenates of the rat brain striatum by HPLC-ECD. The optimum mobile phase on a reverse phase C_18 column was 35mM sodium acetate buffer(included 10mM citric acid, 0.13mM Na_4EDTA, 0.58mM SOS, pH 3·4):MeOH=85:15. The column temperature was 30℃. Dopamine(DA), 3, 4-dihydroxyphenyl acetic acid(DOPAC), homovanilic acid(HVA), 5-hydroxyindole acetic acid(5-HIAA), serotonin(5-HT) and noradrenaline(NA) could be separated and analysed to very small amount. The detection limits of this method were 2~10pg per injection for all components. The effects of age and sex of rat on the contents of the catecholamines and their metabolites in rat brain striatum were studied. The levels of DA and 5-HT contents of the 7 week old female rats were higher than those of the 7 week old male rats. As the age of rat increases, the contents of DOPAC increased significantly.

풍력 발전 시스템의 피치제어

강상수,강승균,임종환,허종철 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.1

Wind turbine system converts wind energy into electric energy. Since the velocity of wind is random in nature, control of the angular velocity of the blade is necessary in order to generate high quality electric power. The control of the blade can be divided into the stall regulation type and the pitch control type. The stall regulation type which utilizes an aerodynamic stall is simple and cheap, but it suffers from fluctuation of the resulting power. On the contrary, pitch control type is based on the fact that the torque of the blade can be changed by varying the pitch angle of the blade. It is mechanically and mathematically complicated, but the control performance is better than that of the stall regulation type. This paper derives a mathematical modeling of the wind turbine system, and suggests a pitch control algorithm. The validity of the algorithm is demonstrated with the results produced through sets of experiments.

자율이동로봇을 위한 직선선분 기반 지도 작성

강승균,임종환,강철웅 제주대학교 공과대학 첨단기술연구소 2004 尖端技術硏究所論文集 Vol.15 No.1

The paper presents an efficient method of extracting line segment in a local map of robot's surroundings. The local map is composed of 2-D grids that have both the occupancy and orientation probabilities based on the bayesian map building model. The local map is continuously updated while the robot explorers its unknown environment and the orientations of all grids in the local map are clustered into several groups according to their values. The line segments are then extracted from the clusters based on least square methods. A merging method that reconstructs lines and corners is developed to build a topological map. The proposed technique is illustrated by experiments in an indoor environment.

RC 서보모튤을 이용한 식사지원 로봇

강철웅,임종환 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.1

We succeeded to build a cost effective assistance robotic arm with a compact and lightweight body. The robotics arm has three joints, and the tip of robotic arm to install tools consists of a closed link mechanism, which consisted of two actuators and several links. The robotic arm has been mad possible by the use of actuators typically used in radio-control servo-modules. The controller of the robotic arm consist of a single chip PIC only. The robotic arm has a friendly user interface, as the operators are aged and disabled in most cases. The operator can manipulate the robotic arm by voice commands of or pressing a push button. The robotic arm has been successfully portotyped and tested on an elderly patient to assist with eating. the results of field test were satisfactory.

자동 이착륙 시스템을 갖춘 모형 헬리콥터 시스템

강철웅,임종환 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.1

In this paper, we introduce an autonomous flying for takeoff and landing a model helicopter with a vision system. A feature of the helicopter is that automatic flying for takeoff and landing is realized by a vision system. Owing to this vision system, the model helicopter is able to takeoff and landing without any human assistance. The vision system is composed of a CCD camera mounted on the helicopter and an image processor on the ground. We first introduce the configuration of the helicopter system, which has a vision sensor, a clinometer and an azimuth sensor. To determine the 3-D position and posture of helicopter, a technique of image recognition using a monocular image is used. Finally we give an experiment result which we obtained in takeoff and landing test with our vision system. This result shows the effectiveness of the vision system in the model helicopter