상호상관 함수를 이용한 지중선로 고장점 추정

朴星完,林泳範,鄭州桓,成洛煥,金喆煥,申明徹 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.2

This paper is intended as an investigation of fault location for underground line. Over the past few decades a considerable number of studies have been made on protection of underground line. However, these approaches require the interruption of electric power supply from source for fault location estimation. Therefore, we proposed fault location algorithm for underground line protection without interruption of electric power supply. Cross correlation function is used in this algorithm. Also, EMTP data is used to demonstrate the capability of the proposed fault location algorithm.

데이터 연관 필터를 이용한 자율이동로봇의 환경지도 작성

임종환,이유철,강철웅 제주대학교 공과대학 첨단기술연구소 2005 尖端技術硏究所論文集 Vol.16 No.2

This paper describes a method of building the probability grid map for an autonomous mobile robot using the ultrasonic DAF(data association filter). The DAF, which evaluates the association of each datum with the rest and removes the data affected by the specular reflection effect, can improve the reliability of the data for the probability grid map. This method is based on the evaluation of possibility that the acquired data are all from the same object. Namely, the data from specular reflection have very few possibilities of detecting the same object, so that they are excluded from the data cluster during the process of the DAF. Therefore, the uncertain data corrupted by the specular reflection and/or multi-path effect, are not used to update the probability map, and hence building a good quality of a grid map is possible even in a specular environment. In order to verify the effectiveness of the DAF, it was applied to the Bayesian model and the orientation probability model which are the typical ones of a grid map. We demonstrate the experimental results using an real mobile robot in a real world.

복식전자궁적출술 후 경막외 통증 관리시 0.1% Bupivacaine/Morphine과 0.1% Ropivacaine/Morphine의 비교

임일환,문철준,반종석,민병우 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.5

Background: Local anesthetics combined with an opioid are frequently used as a postoperative epidural analgesia, to minimize individual doses and to reduce unwanted side effects. The aims of this study were to compare analgesic effectiveness, occurrence of motor block and other side effects of a 48 hr postoperative continuous epidural infusion of 0.1% bupivacaine/morphine or 0.1% repivacaine/morphine. Methods: Forty female patients scheduled for an elective total abdominal hysterectomy under general anesthesia were randomized in a double-blind fashion to receive either 0.1% bupivacaine with 0.02 mg/ml morphine or 0.1% ropivacaine with 0.02 mg/ml morphine using a continuous epidural analgesia pump at a rate of 4 ml/hr during the postoperative 48 hours. After toe operation, we assessed the blood pressure, heart rate, visual analog scale (VAS), side effects, additional analgesic requirement and time to ambulation for 48 hours in 12-hour intervals. Results: There were no significant differences in VAS on rest and cough between the groups, but VAS on deep breathing and position change were significantly lower in the bupivacaine group compared to the ropivacaine group. Side effects were similar in both groups except paresthesia. Time to ambulation was earlier in the ropivacaine troup compared to the bupivacaine group. Conclusions: Both the postoperative continuous epidural infusion of 0.1% bupivacaine with morphine and 0.1% ropivacaine with morphine provided similar pain relief and side effects. However, earlier recovery of ambulation in patients receiving ropivacaine/morphine will improve outcome after abdominal surgery. (Korean J Anesthesiol 2002; 43: 633~639)

그리드 연관성을 이용한 지능로봇용 환경 지도 형상의 신뢰성 향상에 관한 연구

임종환,이세진,강철웅 제주대학교 공과대학 첨단기술연구소 2005 尖端技術硏究所論文集 Vol.16 No.2

This paper addresses a new feature map building method that can minimizes the appearance of phantom features by using only sparse sonar data. The approach is composed of extraction of features and building a probability grid map using only the footprint of sparse sonar data, estimation of position uncertainty of the feature, and evaluation of the reliable features. A virtual circle association frame model has been developed, which associates two sonar footprints into a virtual circle frame. Using this model, geometric primitives such as line, point, or arc features are separately extracted. While extracting the feature, a grid map is also built using the orientation probability approach. Position uncertainty of each extracted feature is, then, estimated by considering both the position uncertainty of the robot and the measurement uncertainty of the sonar sensor. Finally, the reliable features among all extracted ones are evaluated from grid association method. The proposed methods have been tested in a real home environment with a mobile robot.

神經回路網 필터를 利用한 系統周波數 偏移의 推定에 관한 硏究

임영범,김철환 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

A power system disturbance or operating abnormality, can produce a severe generation and load imbalance, resulting in a rapid frequency decline. Therefore, in order to monitor and control power system effectively, it is imperative to estimate frequency accurately. The DFT filter is effective to estimate power system frequency. This paper presents three type of neural network DFT filter to estimate power system frequency. The proposed NN filters are three layer perceptron model using Back-Propagation voltage signal, the NN filters extract the real and imaginary component of it and then the frequency deviation and the frequency of the power system are calculated. This paper compares the result of recursive DFT filter with that of NN filter in estimation of power system frequency.

확장칼만필터 기반 무인잠수정 항법의 성능평가

임종환,강철웅 제주대학교 공과대학 첨단기술연구소 2004 尖端技術硏究所論文集 Vol.15 No.2

This paper presents extended Kalman filter based navigation performances of an autonomous underwater vehicle(AUV). The system is composed of a mother ship (small unmanned marine prober) on the surface of the water and an unmanned underwater vehicle in the water. The mother ship is equipped with a digital compass and a GPS for position information, and extended Kalman filter is used for position estimation. For the localization of the AUV, we used only non-inertial sensors such as a digital compass, a pressure sensor, a clinometer and ultrasonic sensors. From the orientation and velocity information, a priori position of the AUV is estimated by applying the dead reckoning method. A posteriori position of the AUV is, then, updated by using the distance between the AUV and a mother ship on the surface of the water together with the depth information from the pressure sensor. The performances of the navigation system has been estimated in various situations through sets of simulations.

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

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.

조기 및 진행성 위선암종에서 염증반응에 대한 면역조직화학적 그리고 전자현미경적 연구

김환정,임성철,서재홍 조선대학교 2003 The Medical Journal of Chosun University Vol.28 No.1

Background and Object : Solid tumors progressively develop in parallel with a tumor stroma composed of new blood vessels, inflammatory cells and fibrosis Macrophages are a central component of this inflammatory reaction, and they can interact with the neoplastic as well as the stromal components of tumor tissue The "crophage balance' hypothesis was introduced to depict the ambivalent relationship between tumor and macrophages Macrophages might influence neoplastic growth and progression in opposite direction, with a prevailing protumor activity in the absence of therapeutic intervention in many neoplasms. Macrophages, when appropriately activated, are able to eliminate neoplastic target cells in vitro The killing of tumor cells by macrophages requires cell-to-cell contact, but little is known about the mechanisms by which tumor infiltrating macrophages exert their postulated effects in vivo The authors investigated the tumor-infiltrating cells in early gastric carcinoma and advanced gastric carcinoma and described the ultrastructural features and interactions of macrophages with tumor cells and other inflammatory cells Methods : Sections from 20 early gastric carcinomas and 56 advanced gastric carcinomas were stained by immunohistochemical methods for CD4, CD8, CD20, CD45 and CD68 Results : In all of the tumors, CD68-positive macrophages accounted for most tumor-infiltrating cells, followed by CD45-positive T lymphocytes, CD8-positive T lymphocytes &D4-positiveT lymphocytes in order of frequence The authors founded only a few CD20-positive B lymphocytes. Electron microscopy revealed macrophages with phagocytic vesicles and cellular debris The tumor cells in contact with macrophages showed no cymiddleathic changes Contacts among macrophages and other inflammatory cells formed a recurrent ultrastructural hallmark and suggest communication among various inflammatory cell types during the some host response to gastric carcinoma

응집공정에 적합한 In-Line 정적혼화기를 이용한 혼화공정의 개선

정철우,강민수,최시환,정수일,손인식,강임석 대한상하수도학회 2003 상하수도학회지 Vol.17 No.3

The rapid mixing process for coagulation is a critical component in a water treatment plant. However, at the present time a detailed understanding of the rapid mixing by in-line mixer or generally accepted criteria for the design of in-line static mixer are not available. The aim of this work is therefore to improve the understanding of how the in-line static mixer works and how to better utilize it in coagulation process in water treatment. To investigate the performance of static mixer, coagulation experiments were conducted to compare the static mixer to the traditional backmixer under several coagulation conditions. Experiments were also performed to compare the coagulation efficiency of different mixing type of static mixer which were made using different flow rates and the number of elements equipped in a pipe. The static mixer performed better than the backmixer for all coagulation and mixing conditions tested. Especially, the static mixer was very effective in the surface charge neutralization, as showing higher reduction of negative charge with increasing mixing intensity. However, little difference was observed in the performance of the static mixer equipped with 2, 3, and 5 elements. Also, in a series of bench-scale studies of rapid mixing, the in-line static mixer performed better than the traditional backmixer for both adsorption and charge neutralization (A/N) mechanism and sweep coagulation mechanisms. Especially, the static mixer was more efficient at producing A/N mechanism conditions as a result of its fast and uniform dispersion of the coagulant.