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.

생산시스템과 생산전략유형의 적합성 : 개념적 모형 A Concepual Model

林錫賢,鄭燦鎔 釜山 大學校 經營 經濟 硏究所 1994 經營 經濟 硏究 Vol.13 No.1

생산전략과 생산시스템 사이에는 일정한 연계가 있으며 양자간의 적합여부는 기업성과에 큰 영향을 미치는 것으로 생각되고 있다. 이 논문에서는 몇 가지 전략변수를 매개로 하 하여 생산시스템과 생산전략의 적합관계를 결정하는 상황론적 통합모델을 구성하였다. 이를 위하여 생산시스템은 공정유연성과 제품집중성, 생산전략은 제품수량, 제품다양성, 혁신성을 기준으로 하여 각각 여섯 가지로 분류하였다. 이와 같은 적합성모델은 생산시스템과 생산전략의 대응관계가 기업성과에 미치는 영향을 알아보기 위한 실증연구의 개념적 틀을 제공할 수 있을 것이다.

NiTi Rotary Instrumentation이 근관만곡도 변화에 미치는 영향

임형태,홍찬의,조용범 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

During cleaning and shaping of narrow and curved canals, it is very difficult or nearly impossible to maintain the original canal shape. Procedural accidents such as, ledge, zipping, perforation, and instrument breakage are frequently occurred and even may lead to failure of endodontic therapy. To prevent these kinds of accidents, various instrumentation techniques and materials have been introduced. Recently some nickel titanium (NiTi) files are introduced and it is reported that These NiTi files created rounder preparations with less transportation than conventional instruments in curved canals. This study compared the change of the canal curvature and procedural accidents after instrumentation produced by stainless steel K-flexo file, and NiTi rotary files (Profile 29 and Quantec 2000). Thirty narrow and curved canals (25-45 degree) of extracted human molars were randomly divided into three groups. In group 1, canals were instrumented using a step-back and watch-winding/pull motion with K-flexo files. In group 2, canals were prepared with Profile 29. Group 3, canals were prepared with Quantec 2000 files. Before and after preparation of canals, periapical radiographs were taken and scanned. The change of canal curvature were measured using Photoshop 4.0 program and the incidence of procedural accidents were also evaluated. The results were as follows : 1. All group showed some loss of canal curvature after instrumentation. 2. Average loss of canal curvature was 6.70±5.31 degree for group 1, 3.80±2.57 degree for group 2, and 5.40±4.83 degree for group 3. All group There was significant change in curvature between before and after instrumentation (p<0.05). But there was no statistical difference amoung 3 groups. 3. In group 1, there were no procedural accidents, such as ledging, perforation, or instrument fracture. In group 2, two cases of ledge and one case of instrument fracture were produced. Goup 3, each one case of ledge, perforation and instrument fracture were occurred. Whthin the limits of above results, It seems that NiTi rotary instrumentation is not All Mighty and if we use uncarefully, it is more dangerous to produce some procedural accidents than conventional hand files. But more studies should be taken to evaluate the exact effects of NiTi rotary instrumentations.

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

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.

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.

Thermafil 충전법의 근관폐쇄성에 관한 연구

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

주방환기 시스템의 공기 급기구의 위치에 따른 성능평가

임경빈,송시영,이찬호 한밭대학교 생산기반기술연구소 2003 생산기반기술연구소 논문집 Vol.3 No.1

The purpose of this study is to investigate the performance evaluation of indoor diffusion rate of surplus heat generated from gas range and concentration distribution of combustion gas by position change of air- diffuser and range-hood with separating plate. A numerical analysis is performed with four cases of this ventilation system for kitchen. The results showed that thermal and flow distribution can be more effective, when air supply diffuser is located at middle position. Also, Comparisons of Indoor Air Quality(IAQ) are made between using separating plate and not using, IAQ was improved in case of using separating plate and also, kitchen exhaust hood concentration distribution was improved about 30%

배전 네트워크의 정전복구를 위한 휴리스틱 분할기법에 관한 연구

임찬호 경주대학교 정보전자기술연구소 2003 情報電子技術論叢 Vol.2 No.-

Comparing with transmission networks, the faults in distribution networks more often occurs because of the complicated structure and the adjacency to customers. Moreover the faults give direct damage to customers. So fault diagnosis and blackout restoration in distribution networks are very important elements to reduce the damage of customers and to maintain the stability. The restoration problem of distribution networks is subject to time. The restoration process has to be accomplished through several switching. This paper proposes the efficient heuristic division method in distribution networks. The proposed method minimized the time to divide the blackout regions. The proposed system is applied to the sample networks, and the results showed a promising possibility.

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.