폐회로 디젤기관의 모니터링 및 제어를 위한 시뮬레이션 기법에 관한 연구

유춘식 호남대학교 산업기술연구소 1996 산업기술연구논문집 Vol.3 No.-

이 논문에서는 수중 동력용 폐회로 추진시스템에 있어서 산소와 비열비를 모니터량 및 제어하기 위해서 마이크로프로세서를 사용한 하드웨어를 설계하였으며 최적의 제어소프트웨어를 사용한 시뮬레이션기법을 검토하였다. In this paper, a hardware using microprocessors has been designed in order to monitor and control the oxygen and ratio of specific heat in the closed-cycle propulsion system for underwater powerplants. The author examined the simulation technique which imposes an optimal control software.

디지털 도서관을 위한 분산색인 기법에 대한 연구

유춘식,이종득,김용성,Yu, Chun-Sik,Lee, Jong-Deuk,Kim, Yong-Seong 한국정보처리학회 1999 정보처리논문지 Vol.6 No.2

Indexing techniques for distributed resources have much effect on an information service system based on distributed environment like digital library. There is a centralized indexing technique, a distributed technique, and a mixed technique for distributed indexing techniques. In this paper, we propose new distributed indexing technique using EIF(extended Inverted File) structure that mix the centralized technique and t도 distributed technique. And we propose management techniques using EIF structure and retrieval technique using EIF structure. This distributed indexing technique proposed is able to fast process retrieval request and reduce network overload and select servers relevant to query terms. This paper investigated performance of a proposed distributed indexing technique.

재순환 사이클 디젤추진시스템의 모니터링 및 제어를 위한 수학적 모델림에 관한 연구

유춘식 호남대학교 산업기술연구소 1995 산업기술연구논문집 Vol.2 No.-

재순환 사이클 디젤추진시스템은 재래식 디젤기관 추진시스템에서 흡기와 배기 및 이들의 제어에 따르는 문제들을 해결하여 대기로부터 완전히 차단된 환경상태에서 작동되는 시스템이다. 본 연구에서는 5∼50kw, 개방사이클 소형 디젤기관을 대상으로 하고, 주기관, 배기냉각기, CO₂흡수기, O₂혼합기 등으로 부시스템을 구성한 다음 이들의 모니터링 및 제어를 위한 수학적 모델을 도출하였으며, 아울러 각 부시스템에 대한 마이크로프로세서 제어모델을 구성하여 시뮬레이션을 실시하였다. The RDPS is free of the problem of the intake air, exhaust gas and their control that are associated with the conventional diesel propulsion system. It operates in an environment that is shut off from the atmosphere. In this study we looked into a small open cycle diesel engine of 5∼50kw range. We composed the sub-systems of a main engine, an exhaust cooler, a CO₂ scrubber, and a O₂ mixing chamber. Next, we derived a mathematical model for their monitoring and control, Also, we conducted a simulation of the system using a microprocessor control model for each sub-system.

$\mu$-processor를 이용한 폐쇄사이클 디젤추진시스템의 모니터링 및 제어모델에 관한 연구

유춘식 한국마린엔지니어링학회 2004 한국마린엔지니어링학회지 Vol.28 No.6

The closed cycle diesel propulsion system is free from the problem of the intake air, exhaust gas and their control that are associated with the conventional diesel propulsion system. The system is composed of a main engine, an exhaust cooler. a $CO_2$ scrubber and a $O_2$ mixer. In this paper, a hardware using microprocessor is proposed in order to monitor and control the oxygen and ratio of specific heat for underwater diesel propulsion system. Also simulation is carried out to ascertain the performance of proposed system.

유도전동기의 무정류자 크레머형 슬립전력회수 시스템의 최적설계 및 특성에 관한 연구

유춘식,송순일,이형기,노창주 대한전자공학회 1987 대한전자공학회 학술대회 Vol.1987 No.7

X-선(線) 조사(照射)가 Ehrlich 암세포(癌細胞)의 용적(容積), 단백양(蛋白量) 및 수종(數種) Sulfhydryl 기(基)에 미치는 영향(影響)에 관(關)하여

유춘식,주영은,Yu, Choon-Shik,Choo, Young-Eun 대한생리학회 1969 대한생리학회지 Vol.3 No.2

It is well known that a number of -SH and -SS containing substances afford a certain measure of protection against radiation effects in many biological systems, and it is conceivable that inherent -SH levels in Ehrlich ascites tumour (ELD)cells may be of decisive improtance with respect to the development of cellular radiation injury. So far, little effort has been directed to elucidate the changes in levels of different -SH and -SS groups in ELD cells when the tumour-bearing whole animal was subjected to the sublethal dose of X-irradiation. The present study was designed to bring some lights in the possible changes of and relationship between various sulfhydryl levels, such as P-SH, NP-SH and NP-SS, as well as the content of protein and cell volume of ELD cells, after subjecting the ELD mice to 1,200 r of X-irradiation. The animals used in this experiment were all mixed bred mice of $20{\sim}25\;gm$ in body weight (approximately 2 months old) irrespective of sex. 12 mice in one experiment were inoculated intraperitoneally with 0.2 ml of ascites tumour cells $(2{\times}10^6\;cells)$, and on the 7th day of the tumour growth, they were X-irradiated with 1,200 r, using the conventional X-ray machine under the following conditions: 200 Kv at 15 mA, 0.5 mm Cu filter, target-skin distance: 50 cm. Radiation dose was measured with the the Philip integrating dosimeter. At 24, 36, 48 and 60 hours after the X-irradiation, the mice were killed by cervical dislocation, and the tumours were taken out. Freshly withdrawn ascites tumours were placed in ice, and immediately the cell concentration was measured with the Coulter Cell Counter (Model B), and the hematocrit of the tumour cells were also determined. Cell volume was thus calculated by the cell concentration and hematocrit value. P-SH content of ELD cells was measured potentiometrically according to the method of Calcutt & Doxey, and NP-SH and NP-SS contents were measured spectrophotometrically by the method described by Ellman. Protein content of ELD cells was determined with the Folin phenol reagent by Lowry et al. Altogether, 48 experimental mice were used, and 12 mice with the only exception of X-irradiation were used as the control. Results obtained indicate that the contents of all the cellular sulfhydryl groups as well as cell volume and protein content of the ELD cells increase significantly as time progresses after the sub-lethal X-ray dose of 1,200 r was given and that all the increase is in a lineal fashion. The regression lines of the relative values, (i. e., taking each control value as 1) of all the values obtained, and the regression lines of cell volume, protein and NP-SH are identical, whereas those of NP-SS and P-SH appear to be widely seperated. However, the difference of those two lines (NP-SS & P-SH) were found to be not significant statistically (p>0.05). Therefore, it can be concluded from the above results that all the values examined increase in a lineal fashion with no statistically significant difference among them. Also, with the radiation dose of 1,200 r, the ELD cell becomes enlarged and swollen progressively up to 60 hours post-irradiation and it becomes more than two times of the original normal size at 60 hours after the irradiation, and up to this stage, it seems apparent that the cell division has been slow due to the X-irradiation applied in this experiment. It is well understandable that the contents of NP-SH, NP-SS, P-SH and protein of the ELD cells increase in parallel with the increase of the cell volume by the X-ray does used, but it also seems interesting to note that all the cellular substances tested show no appreciable difference in the pattern of increase.

삼상유도전동기의 결상시 전류 및 회전력특성에 관한 연구

유춘식,노창주 한국마린엔지니어링학회 1982 한국마린엔지니어링학회지 Vol.6 No.1

The characteristics of the stator current and torque of a small three- phase squirrel cage induction motor and studied experimentally under the situation of a single-phase operation due to various causes. Through the experiments, the torque-slip and current-slip curve of single-phase circuit as well as three-phase circuit are obtained and the needed constants are determined. The stator current and torque are calculated by the current and torque equations derived by the unbalanced circuit theory. The numerical values obtained from the above methods are compared with the experimental values under the same conditions. The results of the study are summerized as follow; 1) The values computed by the unbalanced circuit theory generally come to approach the values recorded through experiments. 2) Near the rated load, speed drop is less than 1.2 per cent of the speed of three-phase induction motor and torque reduces less than 3 per cent of it of three-phase induction motor when three-phase induction motor is run under a single-phase. On the other hand, the stator current in a single-phase circuit is more than 1.9 times of it in three-phase circuit. 3) The stalling torque in a single-phase circuit is reduced to about 41 per cent of it in three-phase circuit while the corresponding slip is moved toward the synchroneous speed and the corresponding stator current is increased.

유도전동기의 무정류자 크레므형 슬립전력회수 시스템의 적정설계 및 고효율화 운전에 관한 연구

유춘식,홍순일,노창주,이형기 한국마린엔지니어링학회 1987 한국마린엔지니어링학회지 Vol.11 No.4

In this dissertation, a complete model of commutatorless static Kramer type slip power recovery system of 3.phi. induction motor has been designed and tested in the laboratory, and the experimental results are compared with the numerical values. The main results of this study are summerized as follows. (1) Maintenance and repair of the mechanical commutator is obviated by adopting a thyristor commutator in place of the mechanical commutator in the conventional Kramer system. (2) The experimental results of developed torque, and stator current are generally coincided with the numerical values obtained by the derived equation, proving their validity. (3) This system is simulated and the following operational characteristics are obtained with suitable design values : (a) The speed control range of 7:1 is obtained when the turn ratio of induction motor is lowered to about 3:1 to 4:1 and the generating constant of auxiliary synchronous motor is increased to 120-175 range. (b) Its efficiency can be increased to 75-85%, the range for static Scherbius system and its power factor takes values in the range of 65-85%, which is twice of the range for static Scherbius system.

계획정비제도의 개요 ( The Outline of Planned Maintenance System )

유춘식,이의호 한국마린엔지니어링학회 1986 한국마린엔지니어링학회지 Vol.10 No.4

인터넷상에서의 자동차 정보서비스 시스템의 설계 및 구현

유춘식,우선미,김용성,Yu, Chun-Sik,U, Seon-Mi,Kim, Yong-Seong 한국정보처리학회 1999 정보처리학회논문지 Vol.6 No.11

Currently, car information service systems are lack of providing retrieval service, because most of them aim for buying and selling. Thus, in this paper, we design and implement CISS(Car Information Service System on Internet) to provide efficient retrieval for car information. In CISS, we collect information of cars on Internet and construct the lattice structure for efficient retrieval. And we provide retrieval convenience by implementing of Car Browser that permits gradual refinement of the index term by browsing through lattice graph and that permits keyword-based retrieval.