입력 설계기법을 이용한 유연구조물의 다중모드 제어기법 연구

황재혁,권오훈,이혜진 한국항공대학교 항공우주산업기술연구소 2002 航空宇宙産業技術硏究所 硏究誌 Vol.12 No.-

본 논문에서는 유연 구조물의 전류 진동을 제거하기 위한 방법으로 다중모드를 고려하여 제어하는 방법을 연구하고 실험을 하였다. 시간 영역에서의 ZVD-ZVD방법과 주파수 영역에서 근사 시간지연 기법을 시스템의 2차 모드까지 고려하여 입력을 설계하고, 그 설계된 입력을 실험에 적용하여 그 결과를 1차 모드만을 고려하였을 때와 비교하였다. 실험장치는 AC서보 모터에 허브를 달고, 그 허브에 유연한 구조물을 부착하여 구성하였다. 실험에 앞서 시뮬레이션을 위해 실험을 하고자 하는 모델을 모델링하고 운동방정식을 유도한 후, 그 구조물의 회전 시 발생하는 잔류진동을 제거하기 위해 다중모드를 고려하여 입력설계를 하였다. 그리고 시뮬레이션을 통해 얻어진 설계된 입력을 실제 실험장치를 통해 적용을 하였다. 제어 알고리즘은 C언어 프로그램을 이용하여 제작하였고, 실험장치에서 나온 결과값은 스트레인 게이지를 통해 얻어 그 결과를 나타내었다. 본 연구에서는 다중모드를 고려하여 입력을 설계한 경우, 1차 모드만을 제어하였을 때보다 유연구조물에 발생하는 잔류진동을 억제하는데 있어서 더 효과적인 방법임을 시뮬레이션과 실험을 통해 확인하였다. This paper includes our research and experiment on control method in consideration of multi mode to attenuate residual vibration of flexible structure. At first, Input has been shaped taking 2nd mode of system into consideration suing ZVD-ZVD method in a time domain and user selected Time-delay method in a frequency domain. Then, The Result has been obtained by appling the shaped input to the testing equipment. The comparison was made between the above acquired result and the result made when only 1st mode was considered. This paper confirms by simulation and experiment that application of the input shaped by taking multi mode into consideration is more effective method to attenuate residual vibration of flexible structure than when only 1st mode is controlled and No controlled.

항공기 노즈 랜딩기어의 쉬미 해석

황재혁,김두만,남창호,임경호 한국항공대학교 1993 論文集 Vol.31 No.-

본 연구를 통하여 항공기 노즈 랜딩기어의 동안정성을 지배하는 운동방정식을 유도하고, 이를 수치적으로 해석하는 프로그램을 개발하였다. 개발된 프로그램은 어떠한 초기조건 및 파라메타의 변화가 착륙장치의 동안정성에 미치는 영향을 해석하는데 매우 유용한다. 노즈 랜딩기어의 운동 방정식을 해석한 결과, 동적 불안정을 유발시키는 중요한 파라메타를 결정하였고, 이 파라메타들을 적적히 조절하면 지배장정식은 안정된 해를 갖게 된다. 그 중 대표적인 파라메타는 K?,K₃,C이다. 해의 두번째 특징으로 발산하지 않는 해 가운데서 쉬미(shimmy)현상을 나타내는 해가 있다. 쉬미현상은 비선형 시스템에서 나타나는 리미트사이클로서 고정된 진폭과 주파수를 갖고 진동하는 해를 뜻한다. 이러한 쉬미현상을 해석한 결과, 조향계통의 프리플레이(free play)가 쉬미 발생에 결정적인 원인이 됨을 확인 하였다. In this study, the equations of motion of an nose landing gear system for shimmy analysis has been derived and then the equations have been solved by numerical method. The developed program in this study is useful to evaluate the effect of the initial conditions and parameters of the nose landing gear on the its dynamic stability. It has been found that the parameters such as K?K₃,C? play the most prominent role on the dynamic stability of the nose landing gear. Shimmy is a kind of limit cycle which can be occurred in the nonlinear dynamic systems. Shimmy has been analyzed numerically in this paper. It turns out that the free play in the steering system is the most important factor to generate shimmy.

有限要素法에 의한 大變形問題의 彈塑性 解析

황평,채영석,이택순,황재석,김동섭 영남대학교 공업기술연구소 1984 연구보고 Vol.12 No.1

The nonlinear analysis must be carried out when the deflection is large enough to cause non-linear behavior of the plate and the results of stress distributions are significantly different from those of ordinary small deflection theory. In present study, the nonlinear analysis of stiffened plate has been done based on von Karman's non-linear plate equations for isotropic plate using Lagrangian description finite element method. In this method, it is shown that the small deflection theory to the plate is applicable when the deflection of the plate is less than about a half of the plate thickness and above this range, large deformation theory is adequate. For the case of perforated rectangular plate with clamped boundary condition, it is found that the stress intensity of the edge reduces but that of the hole tip increases. In that case, doubler decreases the stress intensity at the tip, while stiffener decreases stress intensity at the tip and edge. It is also found that the maxinmum load carrying capacity of perforated stiffened plate increases 5 times as much as in the perforated plate. This method would be applied and extended to solve both geometrical nonlinearity and material nonlinearity problems and be useful to save computation time in engineering sense.

통신프로토콜의 적합성시험열 생성을 위한 경로 탐색 방법

황익순,장민석,이상배,이재용 延世大學校 電波通信共同硏究所 1996 電波通信論文誌 Vol.2 No.1

본 논문에서는 적합성 시험에서 EFSM(Extend Finite State Machine) 모델에 대한 데이타부분 시험열을 효율적으로 생성시켜 주는 탐색 방법에 대해 제안하였다. 이 탐색 방법에서는 depth-first search와 같은 기존의 탐색 방법과는 달리 탐색 초기에 다양한 경로가 찾아진다. 이미 제안된 시험열 생성 방법인 데이타 값을 바탕으로 하여 시험열을 생성하는 방법에서 이 탐색 방법을 이용하였을 경우 기존의 탐색방법을 이용하는 것보다 효율적으로 시험열을 생성할 수 있다. 본 논문에서는 Inres 프로토콜에 이 탐색 방법과 기존의 탐색 방법인 depth-first search를 각각 적용하여 시험열을 생성, 비교하여 보았으며, 제안된 탐색 방법을 이용하면 같은 시험 범주를 가지면서도 짧은 길이를 갖는 시험열을 효율적으로 생성할 수 있음을 알 수 있다. In this paper we proposed a searching algorithm for generating test cases, which can test data part of EFSM model in conformance test. In a different way to existing algorithm like depth-first search algorithm, this one can find various paths in the early stage of searching. When it is used in readily proposed test case generation method which is based on the value of variables and parameters it can generate test cases efficiently than in the case of depth-first search algorithm being used. We generated test cases for Inres protocol using each of proposed and depth-first search algorithm, and compared these two methods. proposed algorithm can generate much shorter test sequences efficiently than existing one.

뉴-라운드를 고려한 ISO 14000시스템 구축에 관한 연구

황상호,조재립 경희대학교 산학협력기술연구원 2000 산학협력기술연구논문집 Vol.6 No.-

After the failure of the WTO talks in Seattle, the European Union and the United States are likely to become increasingly protective, making it important to bolster competitiveness in all sectors in order to survive globalization. Korea will have to prepare for the changes in the international economic environment. New trade issues - Environment, Labor, Investment, Competitive Policy, E-Commerce...- stand out in bold relief. Like our country that depend on exports for their economic growth, this nation has not given up hope on the need for the liberalizing international trade rules. Surely, some hypothetical case studies must be designed as preparatory training for bankers, major corporations government officials. Sectors with low competitiveness must try to find ways to boost it. Trade friction in the auto, steel, pharmaceutical and ship building industries can be reduced by softening domestic regulations. Challenges lie ahead for Korea in New Round. The primary objective this study is to provide the basis of environmental quality management policies by reviewing previous studies on ISO 14000 and its case studies.

C_3 및 C_7위치에 치환된 새로운 세파로스포린 化合物의 合成과 抗菌活性(Ⅰ)

황화영,하재천,김영수,고옥현,강형룡 조선대학교 약학연구소 1994 藥學硏究誌 Vol.16 No.1

The synthesis and antimicrobial activity of cephalosporin having (Z)-2-(2-aminothiazol-4-yl)-2-trityloxyiminoacetamido group and 5-(2-chlorophenyl)-4-phenyl-4H-1, 2, 4-triazol-3-thiomethyl group on the C_3 and C_7 position of the cephem ring, respectively are descrived. This compound was tested for antimicrobial activity in vitro against Candida albicans ATCC 10231, Bacillus subtilis ATCC 6633, Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 6538P, Mycobacterium phlei IIP-IPH, Escherichia coli KCTC 1039, Escherichia coli ESS, Klebisiella pneumoniae KCTC 1560, Salmonella typhymurium TV-119, Pseudomonas aeruginosa IFO 13130. The antimicrobial activity of synthetic compound was better as compare with cefotaxime and cefazoline against Micrococcus luteus ATCC 9341 & Escherichia coli KCTC ESS.

독립모달공간 제어기법에서 작동기의 수 및 최적위치 선정

황재혁,백승호 한국 항공대학교 항공산업기술연구소 1994 航空宇宙産業技術硏究所 硏究誌 Vol.4 No.-

In this study, a new formulation of independent modal space control is developed to handle the attitude and vibration control problem for large flexible structures. The main advantage of this method is that one can obtain an analytical solution for the optimal control law for very large order systems. The fundamentaal limitation of previous works, the requirement of one actuator for each mode to be controlled, is relaxed in the new formulation. The closed-loop design is obtained while independently assuring stability and the design may be iterated to improve the closed-loop dynamic characteristics. The ease of control law generation by this method is seen to be obtained at the expense of the ability to adjust directly the penalties on the actuator efforts. Since actuator optimal placement is of fundamental importance, three methods which are simple to use for determination of optimal actuator locations have been suggested.

環境條件이 다른 두 湖水에 있어서 植物成 Plankton 群集의 特性에 關한 硏究 : II. 植物性 Plankton 群集의 種構性 變動 Ⅱ. Seasonal changes in phytoplankton

黃淳珍,玄在善 서울大學校 農科大學 1986 서울대농학연구지 Vol.11 No.1

A study was made to examine some of the community characteristics of phytoplankton in two reservoirs, having different environmental conditions, on the outskirts of Suwon city, Kyonggi province. Monthly samples were taken from September, 1984, to August 1985, using Kemmlerer, except December, 1984. Total identified species of phytoplankton were 142 in 66 genera, and the numbers of species were 96 in 52 genera for Ilweol reservoir, and 117 species in 60 genera for Ucheon reservoir. The average densities of the phytoplankton were much greater in Ilweol reservoir than in Ucheon reservoir, and the differences were greater at the time of blooms. The blooms of phytoplankton were in May, July and September for Ilweol reservoir while they were in April, July and September for Ucheon reservoir. The dominant taxonomic groups were Oscillatoria, Anabaena, Microcystis, Merismopedia, Scenedesmus. Micractinium, Ankistrodesmus, Golenkinia and Cyclotela for Ilweol Reservoir. While they were Synedra, Fragilaria, Tabellaria, Staurastrum Characium, Pleurotaenium, Asterococcus, Chlorella, and Oscillatoria for Ucheon reservoir, depending on the Seasons. The dominance indices of phytoplankton were greater throughout the year at Ilweol reservoir, while species diversity components, Shanno-Weaver, evenness, and variety indices, were greater in Ucheon reservoir. From the results of the biological indicators in the phytoplankton species, Ilweol reservoir seemed to be already eutrophicated and Ucheon reservoir seemed to be on the way to the mesotrophic state.

코스틱스법에 의한 순수 전단장치 평가에 관한 연구

황재석,김원현,서정희 嶺南大學校 工業技術硏究所 1998 工業技術硏究所論文集 Vol.26 No.1

There are many experimental devices for pure shear test such as off-axis tension test pure shear test for Iosipescu conceptions. Arcan circular disk for Arcan conceptions and the general pure shear test and Hawong Iosipescu shear test(H.I.S.T.) etc.. Hawong Iosipescu shear test(H.I.S.T.) device is analyzed through caustics. It is assured that H.I.S.T. device is more effective than Iosipescu shear test(I.S.T.) device for the measurement of stress intensity factor from causic. It is known that H.I.S.T. device without notch is most effective as pure shear test device, between H.I.S.T. device and I.S.T. device for caustics, but H.I.S.T .device and I.S.T. devices are can be used ad pure shear test device

중년 여성에서 발생한 집합관 신세포암 1 예

황인성;정재현;유지형;성락희;노충희;정재용;김현정 인제대학교 2011 仁濟醫學 Vol.32 No.-

Collecting duct renal cell carcinoma (CDRCC) or Bellini duct carcinoma is a rare type of renal cell carcinoma (RCC), accounting for 0.4% to 1.8% of all RCC. CDRCC is considered to originate from the collecting duct of the kidney and it has a poor prognosis. However, the clinical features of CDRCC remain poorly understood, mainly because only studies with a small series or case reports have been published to date. We experienced a case of CDRCC of kidney.