A Study on the Design of Power System Stabilizer Using DeadBeat Control

Lim, Chan-Ho 慶州大學校 2005 論文集 Vol.18 No.2

데드비트제어는 리플이 없는 출려응답을 얻을 수 있고, 정해진 샘플링 주기 후에 오차 없는 정상상태에 도달하는 특성을 가지고 있다. 본 논문에서는 이러한 특성을 가진 데드비트 제어기를 전력계통 안정화 제어기에 적용하여, 전력시스템의 저주파 진동현상을 제어하기 위한 방안을 제안하였다 제안된 데드비트제어기는 적분제어기와 상태관측기 및 영차홀드로 구성하여 설계하였으며, 성능 검증을 위하여 최적 제어기와 비교 시뮬레이션을 수행하였다. 시뮬레이션 결과 초기상태에 의한 출력응답의 경우에 있어서 최적제어기 보다 1.5배 빠르게 정상상태에 도달하였고, 리플이 없는 응답을 보였다.

가변 광도 중합에 따른 복합레진의 중합수축에 관한 연구

임미영,조경모,홍찬의 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.1

본 연구는 광중합형 복합레진 중합 시 기존의 중합법과 가변광도 중합형인 soft start 중합법 및 exponential 중합법 간의 중합수축효과를 비교하고자 하였다. 본 연구를 위해 3종의 복합레진 (Synergy Duo Shade, Z250, Filtek Supreme) 및 3종의 광조사기 (Spectrum 800, Elipar Highlight, Elipar Trilight)를 사용하였다. 총 중합시간은 40초로 일정하게 유지하였으며, 선형 중합수축률의 측정은 linometer를 이용하였으며, 90초간의 선형 수축률을 0.5초 간격으로 측정하였다. 재료별로 각 중합 방법별 시간에 따른 중합수축률을 one-way ANOVA test로 분석하여 최종 중합수축률에 도달하는 시간을 산출하였고, 90초 후 최종 선형 중합수축률을 two-way ANOVA test를 이용하여 재료, 광조사 방법, 재료 및 광조사 방법의 교호작용이 중합수축에 미치는 영향이 있는지를 검증하였다. 또한 90초까지의 선형 중합수축률에 대한 20초까지의 선형 중합수축률의 비를 two-way ANOVA로 비교하고, 각각의 통계치를 95% Scheffe test로 검증하였는바, 다음과 같은 결과를 얻었다. 1. Supreme을 제외한 다른 군에서는 재료 및 광조사 방법에 관계없이 대부분의 중합 수축이 광조사 후 20초 이내에 이루어졌다 (p < 0.05). 2. 90초 후, 최종 중합수축률은 재료 (p = 0.000)와 광조사 방법 (p = 0.003) 모두 유의성 있는 영향을 끼쳤으나, 재료와 광조사 방법 상호간의 작용은 영향이 없었다. 3. 90초 후 최종 중합수축률은 총 광에너지가 가장 낮은 exponential 중합법에서 유의성 있게 낮았다 (p < 0.05). 4. 20초까지의 초기 수축률은 soft start와 exponential 중합법 등 가변광도 중합이 conventional 중합법에 비하여 유의성 있게 낮은 수축률을 보였다 (p < 0.05). 본 실험 결과만을 토대로 볼 때, 가변광도 중합법은 초기 중합수축 속도를 감소시켜 수축응력을 감소시킨다고 볼 수 있다. 그러나 총 조사 광에너지의 차이로 인해 그 물리적 성질에 영향이 있을 수 있으므로 향후 이에 대한 더 많은 고찰이 필요할 것으로 사료된다. The purpose of this study was to compare the effect of exponential curing method with conventional curing and soft start curing method on polymerization shrinkage of composite resins. Three brands of composite resins (Synergy Duo Shade, Z250, Filtek Supreme) and three brands of light curing units (Spectrum 800, Elipar Highlight, Elipar Trilight) were used. 40 seconds curing time was given. The shrinkage was measured using linometer for 90 seconds. The effect of time on polymerization shrinkage was analysed by one-way ANOVA and the effect of curing modes and materials on polymerization shrinkage at the time of 90s were analysed by two-way ANOVA. The shrinkage ratios at the time of 20s to 90s were taken and analysed the same way. The results were as follows: 1. All the groups except Supreme shrank almost within 20s. Supreme cured by soft start and exponential curing had no further shrinkage after 30s (p < 0.05). 2. Statistical analysis revealed that polymerization shrinkage varied among materials (p = 0.000) and curing modes (p = 0.003). There was no significant interaction between material and curing mode. 3. The groups cured by exponential curing showed the statistically lower polymerization shrinkage at 90s than the groups cured by conventional curing and soft start curing (p < 0.05). 4. The initial shrinkage ratios of soft start and exponential curing were statistically lower than conventional curing (p < 0.05). From this study, the use of low initial light intensities may reduce the polymerization rate and, as a result, reduce the stress of polymerization shrinkage.

쌍대단체법의 효율적인 구현을 위한 기법

임성묵,박찬규,김우제,박순달 한국경영과학회 1999 經營 科學 Vol.16 No.1

The purpose of this paper is to develope efficient techniques for implementing the dual simplex method in this paper we proposed one artificial row technique to get an initial dual feasible basic solution, a dual steepest-edge method coupled with a dropping row selection rule, and an anti-degeneracy technique which resembles the EXPAND procedure for the primal simplex method the efficiency of the above techniques is shown by experiments Finally, the dual simplex method is shown to be superior to the primal simplex method when it is used in the integer programming

Thermafil 충전법의 근관폐쇄성에 관한 연구

임성삼,여인호,박찬제 大韓齒科保存學會 1996 Restorative Dentistry & Endodontics Vol.21 No.2

京畿西部地域 乳牛의 牛白血病 抗體陽性率에 대한 調査硏究

林贊燮,金泰鍾 건국대학교 동물자원연구센터 1992 動物資源硏究誌 Vol.17 No.-

This survey was carried out to detect the bovine leukosis virus antibody from 223 dairy cattle rearing in Western Kyeonggi area by the agar gel immunodiffusion test using bovine leukosis virus(BLV) glyco-protein antigens. Lymphocytes rates for total white blood cell(WBC) in the BLV antibody positive cattle were also determined with the blood cell analyzer and blood smear stained with Giemsa's standing. The results obtained from this survey were as follows : 1. The overall positive rate was 15.70% in 223 heads surveyed. 2. The infection rate was various depending on the surveyed area, 7.50% (3 heads out of 40 heads surveyed) in Incheon, 4.84%(3 heads out of 62 heads surveyed) in Northern Kimpo, 22.97%(17 heads out of 74 heads surveyed) in Southern Kimpo and 25.53%(12 heads out of 47 heads surveyed) in Siheung area. 3. In the hematological findings, lymphocytes rate(above 70%) for total WBC in the 35 BLV antibody positive cattle was observed at 11 heads(31.43%).

전자 렌즈에서 초점 거리와 프르브 전류의 관계

임선종,이찬홍 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

The focal length decreases as the current increase. The focal length increases at higher accelerating voltages for the same lens excitation since the velocity of the electrons increases with increasing beam voltage. If the focal length is short, probe current is small because the most part of electrons connect on aperture. In this paper, we analysis the relation between focal length and probe current. In the measurement of probe current, faraday cup is used for it and it does not allow the backscattered and secondary electrons generated by the incident beam to escape.

퍼지 제어기의 비선형 특성 향상을 위한 계수동조 기법에 관한 연구

임찬호 경주대학교 2001 論文集 Vol.14 No.-

The fuzzy theory has been applied to the control systems due to its excellent properties on the nonlinear systems. But the design process of fuzzy controller requires empirical and heuristic knowledge of human experts as well as many trial-and-errors in general. This process is time consuming task. The simulated annealing is the optimization algorithm which guarantee the global optimum. This paper presents an parameters tuning method of the fuzzy controller using the simulated annealing. The proposed tuning method is applied to the fuzzy controller for the low frequency oscillation of a synchronous generator. Through the comparative simulation with linear controller under various operating conditions, the robustness of fuzzy controller is verified. And the efficiency of the proposed tuning method is verified.

변전소 상태추정을 위한 실시간 위상구조 처리기에 관한 연구

임찬호 경주대학교 정보전자기술연구소 2007 情報電子技術論叢 Vol.6 No.-

State estimation is the function for an error correction of an analog data measured in EMS (Energy Management System) or SCADA system. Topology processing is indispensable basic function in order to generate a system matrix for state estimation of substation. This paper propose an expert system to generate system matrix automatically using artificial intelligence technology and it is applied to 154kV distribution substations. This expert system will be applied to state estimation systems and contribute to improving reliability of a substation automation system.

지역급전 분소에서의 통합 고장진단을 위한 퍼지 전문가 시스템에 관한 연구

임찬호 경주대학교 정보전자기술연구소 2005 情報電子技術論叢 Vol.4 No.-

During the last decade, a lot of expert systems have been proposed to cope with various problems in power system to make toward the eventual dream of fully automated reliable power system, This paper presents a practical fuzzy expert system to diagnose various faults occurred in local power systems. This integrated system can diagnose all faults occurred in a transmission network and substations. In this paper, the fuzzy reasoning of the diagnostic process is discussed in detail. The discrimination of false operations and non-operations of protective devices as well as the fault identification scheme are also analyzed together with the fuzzy inference process. The efficiency of the proposed fuzzy expert system is verified through the several case studies.

중앙심벽형댐의 응력전이에 관한 연구

임희대,임찬수,이성용 忠南大學校 産業技術硏究所 1995 산업기술연구논문집 Vol.10 No.2

Various modes of load transfer may exist in rockfill dams. If the core is softer than the shells, load is transferred from the core onto the shells as a result of greater downward displacement of the core with respect to the shells. But if the core is stiffer than the shells, load transfer occurs from the shells onto the core. In this study, the mechanisms of load transfer in rockfill dams have been outlined and load transfer of Juam main and regulation dam with central core are evaluated by load transfer ratio. The load transfer ratio is defined as the ratio of computed values of major principal stresses in the core to the core overburden stresses. The vertical stresses are determined by the FEM, which use hyperbolic model and incremental method to simulate placement of successive layers of fill. The hyperbolic paramaters for the core was estimated from a series of conventional triaxial tests carried out during construction. From the results of this analyses and its comparison with the values measured by soil pressure meters, it has been shown that significant load transfer from the core to the shells was observed in two dams and that the load transfer ratios predicted are higher than the values measured.