• 한국유체기계학회 논문집
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• 제12권5호
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• pp.7-12
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• 2009

A nuclear fuel test loop(after below, FTL) is installed in the IRI of an irradiation hole in HANARO for testing the neutron irradiation characteristics and thermo hydraulic characteristics of a fuel loaded in a light water power reactor or a heavy water power reactor. There is an in-pile section(IPS) and an out-pile section(OPS) in this test loop. When HANARO is operated normally, the fuel loaded into the IPS has a nuclear reaction heat generated by a neutron irradiation. To remove the generated heat and to maintain the operation conditions of the test fuel, a main cooling water system(MCWS) is installed in the OPS of the FTL. The MCWS is composed of a main cooler, a pressurizer, two circulation pumps, a main heater, an interconnection pipe line and instruments. The interconnection pipeline is a closed loop which is connected to an inlet and an outlet of the IPS respectively. The MCWS is under a cold function test during a start-up period. This paper describes the system flow network analysis results of the flow control of a main cooling water system in the HANARO fuel test loop. It was confirmed through the results that the flow was met the system design requirements.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.462-466
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• 1997

Proportional directional control valves (PDCVl adjust the amount of flow as well as flow direction in response to an electrical signal. This valves includes direct operated valves with or without spool position feedback. This paper investigates if it is possible to control pressure of fluids by means of the PDCV. A pressure signal is feed back to the Proportional-Integral (PI) controller, which is based upon a personal computer (PC). The PI control algorithm is implemented in a graphical programming language of LabVIEW. The results of experiments show the PDCV can be used a multi function valve of pressure control as well as direction control.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제22권3호
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• pp.145-150
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• 2016

프로그램 내에서 오류의 정확한 위치를 찾아내는 것은 많은 시간과 노력을 필요로 하는 작업이다. 이러한 문제를 해결하기 위하여 프로그램의 제어 흐름을 이용한 자동화된 오류 위치 추정 기법이 오랫동안 연구되어 왔으나, 데이터 흐름 기반 언어로 작성된 프로그램에 대해서는 적용될 수 없다는 한계가 있다. 최근 개발된 뮤테이션(mutation) 기반 오류 위치 추정 기법의 경우 프로그램의 제어 흐름 대신 뮤턴트(mutant)라 불리는 인공 오류를 활용하기 때문에 데이터 흐름 기반 언어로 구현된 프로그램에 대해서도 활용될 수 있을 것으로 기대되나, 오류 위치 추정 효과성에 대한 연구는 이루어지지 않았다. 본 연구는 데이터 흐름 기반 언어인 Function Block Diagram (FBD)로 구현된 프로그램을 대상으로 뮤테이션 기반 오류 위치 추정 기법이 실제 오류의 위치를 얼마나 정확하게 추정할 수 있는지에 대한 사례 연구를 수행한다. 실제 원자로 보호 시스템 대상 초기 버전에 사용되었던 FBD 프로그램에서 발견된 오류들을 수집하고, 각 오류별 위치 추정의 효과성을 분석한다.

• Journal of Communications and Networks
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• 제11권3호
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• pp.297-305
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• 2009

Multiprotocol label switching (MPLS) networks require dynamic flow admission control to guarantee end-to-end quality of service (QoS) for each Internet protocol (IP) traffic flow. In this paper, we propose to tackle the joint routing and admission control problem for the IP traffic flows in MPLS networks without rerouting already admitted flows. We propose two mathematical programming models for this problem. The first model includes end-to-end delay constraints and the second one, end-to-end packet loss constraints. These end-to-end QoS constraints are imposed not only for the new traffic flow, but also for all already admitted flows in the network. The objective function of both models is to minimize the end-to-end delay for the new flow. Numerical results show that considering end-to-end delay (or packet loss) constraints for all flows has a small impact on the flow blocking rate. Moreover, we reduces significantly the mean end-to-end delay (or the mean packet loss rate) and the proposed approach is able to make its decision within 250 msec.

• 전기학회논문지
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• 제58권4호
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• pp.671-678
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• 2009

This paper presents target operation voltage guidelines of each voltage control area considering both voltage stability and economical efficiency in real power system. EMS(Energy Management System) data, Real-time simulator, shows not only voltage level but lots of information about real power system. Also this paper performs optimal power flow calculation of three objective functions to propose the best target operation voltage. objective function of interchange power flow maximum and active power loss minimization stand for economical efficiency index and reactive power reserve maximum objective unction represents stability index. Then through simulation result using optimazation technique, the most effective objective function is chosen. To sum up, this paper divides voltage control area into twelve considering electric distance characteristics and estimate or voltage level by the passage of time of EMS peak data. And through optimization technique target operation voltage of each voltage control area is estimated and compare heir result. Then it is proposed that the best scenario to keep up voltage stability and maximize economical efficiency in real power system.

• Journal of Chest Surgery
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• 제22권4호
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• pp.580-588
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• 1989

The potential for enhancing myocardial protection by adding high-energy phosphate to cardioplegic solutions [St. Thomas Hospital solution] was investigated in a rat heart model of cardiopulmonary bypass and ischemic arrest. Creatine phosphate was evaluated as an additive to the St. Thomas Hospital cardioplegic solution. Creatine phosphate 10.0 mmol/L as the optimal concentration which improved recovery of aortic flow and cardiac output after a 30 minute period of normothermic [37oC] ischemic arrest. In comparing mechanical function in both groups the mean postischemic recoveries of aortic flow, cardiac output, stroke volume and stroke work [expressed as a percentage of its preischemic control] were significantly greater in STH-CP group than in CP- free control group. In addition to improving function and decreasing CK release, CP reduced reperfusion arrhythmias significantly decreasing the time between cross-clamp removal and return to regular rhythm from 81.8 * 13.9 [sec] in CP-free group to 35.9 * 6.8 [sec] in CP group [P< 0.05] so, exogenous CP exerts potent protective and antiarrhythmic effects when added to the St. Thomas Hospital cardioplegic solution. However, the mechanism of action remains to be elucidated.

• 혜화의학회지
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• 제15권2호
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• pp.263-272
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• 2006

Purpose Brain vessles have autoregulation function, so even when perfusion pressure drops, cerebral blood flow remain stable by vasodilation. Latest research on this reserve of cerebral vessels is being done using TCD, which measures the reserve of the vessels. We did a research comparing cerebral vessel and peripheral vessel reserve between Taeumin, who are more likely to suffer CVA, and the normal. We observed blood flow of Internal carotid artery siphon and radial indicis artery of the two group with TCD. Method We picked 20 people out of patients diagnosed as cerebral infarction at Cheon-An Oriental hospital of Daejeon University. They were diagnosed as Taeumin with QSCCII questionnaire and constitutional differentiation. Using TCD, we measured highest blood flow rate, mean blood flow and asymmetric counting blood flow of Internal carotid artery siphon and radial indicis artery at rest. And then we measured again after stimulating cerebral vessels, by triggering hypercapnia by self apnea and peripheral vessels by palm heating. Result At rest, mean blood flow rate of Internal carotid artery siphon showed significant decrease compared to control group. Blood flow rate of Internal carotid artery siphon after hypercapnia showed significant decline in highest blood flow rate and mean blood flow compared to control group. Cerebral vessel reaction after the hypercapnia induction showed great change in experiment group than the control group. Peripheral vessel reaction after palm heating showed significant decline in experiment group compared to control group. Conclusion In conclusion, measuring the alteration of blood flow used in diagnosing cerebral infarction, is more sensitive when vessel stimulation is done. Non-invasive TCD is effective especially in case of Taeumin who are more likely to suffer vascular disorder than others.

• KIEE International Transaction on Systems and Control
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• 제2D권2호
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• pp.78-91
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• 2002

In the thermal power plant, there are six manipulated variables: main steam flow, feedwater flow, fuel flow, air flow, spray flow, and gas recirculation flow. There are five controlled variables: generator output, main steam pressure, main steam temperature, exhaust gas density, and reheater steam temperature. Therefore, the thermal power plant control system is a multinput and output system. In the control system, the main steam temperature is typically regulated by the fuel flow rate and the spray flow rate, and the reheater steam temperature is regulated by the gas recirculation flow rate. However, strict control of the steam temperature must be maintained to avoid thermal stress. Maintaining the steam temperature can be difficult due to heating value variation to the fuel source, time delay changes in the main steam temperature versus changes in fuel flow rate, difficulty of control of the main steam temperature control and the reheater steam temperature control system owing to the dynamic response characteristics of changes in steam temperature and the reheater steam temperature, and the fluctuation of inner fluid water and steam flow rates during the load-following operation. Up to the present time, the Proportional-Integral-Derivative Controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper focuses on the characteristic comparison of the PID controller and the modified 2-DOF PID Controller (Two-Degrees-Freedom Proportional-Integral-Derivative) on the DCS (Distributed Control System). The method is to design an optimal controller that can be operated on the thermal generating plant in Seoul, Korea. The modified 2-DOF PID controller is designed to enable parameters to fit into the thermal plant during disturbances. To attain an optimal control method, transfer function and operating data from start-up, running, and stop procedures of the thermal plant have been acquired. Through this research, the stable range of a 2-DOF parameter for only this system could be found for the start-up procedure and this parameter could be used for the tuning problem. Also, this paper addressed whether an intelligent tuning method based on immune network algorithms can be used effectively in tuning these controllers.

• 한국정보통신학회논문지
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• 제4권2호
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• pp.313-322
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• 2000

최근 ATM Forum은 ABR 트래픽 관리를 위한 흐름제어 메커니즘에 중점을 두고 있다. 이 연구의 목적은 통신 링크를 최적화하기 위해 잔여 대역폭을 효율적으로 관리하고 경쟁하는 ABR VC들 사이에 공정하게 분산시키기 위한 것이다. ABR 트래픽은 가변적이고 버스트한 특성 때문에 트래픽의 형태를 예측하기 어렵고 또한 지연에는 민감하지 않지만 손실에 민감하다. 이러한 특성은 네트워크의 UPC 기능을 어렵게 만들고 스위치에서 폭주를 유발하여 성능을 감소시킨다. 이러한 문제를 해결하기 위해 ATM Forum에서 다양한 흐름제어 메커니즘이 연구되었다. 특히, 속도 기반 방식이 ABR 트래픽에 대하여 표준화되었고, EFCI, ER, VS/VDdhk 같은 다양한 흐름제어 메커니즘이 연구되고 있다. VS/VD는 서로 다른 네트워크를 격리함으로써 기존의 ER 방식보다 성능이 더 우수하다. 본 논문에서는 확장된 VS/VD 흐름제어 알고리즘을 제안하고 기존의 큐임계값 방식을 적용한 VS/VD 흐름제어 알고리즘과 비교한다. 시뮬레이션 결과로 지연과 공정성 측면에서 문제점을 개선하는 것을 보인다.

• 국제물리치료학회지
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• 제2권2호
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• pp.301-307
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• 2011

The purpose of this study was an determine whether elastic band on treadmill training might effect the chest expansion and pulmonary function of the 20's men. 40 subjects with experimental group(male: 20) and control group(male: 20) was participated in experiment. During four weeks, each group participated thirty minutes for three times per week. Subjects were assessed using pre-value and post-value measurement chest length(chest length for resting, chest expansion) and pulmonary function(forced vital capacity, forced expiratory volume at one second, FEV1/FVC, peak expiratory flow, vital capacity, tidal volume, expiratory reserve volume, inspiratory reserve volume) by the CardioTouch 3000S(BIONET, USA). These findings suggest that experimental group can be used to improve chest expansion, pulmonary function than control group. In comparison of both groups, post-test was more improved in experimental group. In conclusion, experimental group helped improving function of pulmonary volume and respiratory muscle, and thus it indicates that the functions will be more improved through the continued respiratory exercise program.