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이윤형(Yun-Hyung Lee),안종갑(Jong-Kap Ahn),소명옥(Myung-Ok So),이준탁(Jun-Tack Lee) 한국마린엔지니어링학회 2007 한국마린엔지니어링학회 학술대회 논문집 Vol.2007 No.-
A simple tuning methods of PI, PD and PID controller are proposed for an integrating process with time delay. This is based on matching the coefficients of corresponding powers of s in the numerator and that in the denominator of the closed-loop transfer function. For set-point tracking problem, the derived controller is found to be a PD controller which is shown by Lee's tuning rule based on minimizing the performance indexes (lSE, IAE, ITAE) using a real-coded genetic algorithm. A method can be also proposed PI, PID controllers according to tuning parameter lambda (A) similar to IMC method. Simulation example is given to illustrate the set-point tracking performance of the proposed method.
Lee, Hyun-Woo,Lee, Ki-Tack,Lee, Bang-Yong The Korean Society of Oceanography 2008 Ocean science journal Vol.43 No.4
This paper evaluates whether a thermodynamic ocean-carbon model can be used to predict the monthly mean global fields of the surface-water partial pressure of $CO_2$ ($pCO_{2SEA}$) from sea surface salinity (SSS), temperature (SST), and/or nitrate ($NO_3$) concentration using previously published regional total inorganic carbon ($C_T$) and total alkalinity ($A_T$) algorithms. The obtained $pCO_{2SEA}$ values and their amplitudes of seasonal variability are in good agreement with multi-year observations undertaken at the sites of the Bermuda Atlantic Timeseries Study (BATS) ($31^{\circ}50'N$, $60^{\circ}10'W$) and the Hawaiian Ocean Time-series (HOT) ($22^{\circ}45'N$, $158^{\circ}00'W$). By contrast, the empirical models predicted $C_T$ less accurately at the Kyodo western North Pacific Ocean Time-series (KNOT) site ($44^{\circ}N$, $155^{\circ}E$) than at the BATS and HOT sites, resulting in greater uncertainties in $pCO_{2SEA}$ predictions. Our analysis indicates that the previously published empirical $C_T$ and $A_T$ models provide reasonable predictions of seasonal variations in surface-water $pCO_{2SEA}$ within the (sub) tropical oceans based on changes in SSS and SST; however, in high-latitude oceans where ocean biology affects $C_T$ to a significant degree, improved $C_T$ algorithms are required to capture the full biological effect on $C_T$ with greater accuracy and in turn improve the accuracy of predictions of $pCO_{2SEA}$.
Lee, Hyun-Woo,Lee, Ki-Tack,Kaown, Duk-In The Korean Society of Oceanography 2008 Ocean science journal Vol.43 No.1
Over a period of 5 days between August 12 and 17, 2005, we performed a gas exchange experiment using the dual tracer method in a tidal coastal ocean located off the southern coast of Korea. The gas exchange rate was determined from temporal changes in the ratio of $^3He$ to $SF_6$ measured daily in the surface mixed layer. The measured gas exchange rate($k_{CO_2}$), normalized to a Schmidt number of 600 for $CO_2$ in fresh water at $20^{\circ}C$, was approximately $5.0\;cm\;h^{-1}$ at a mean wind speed of $3.9\;ms^{-1}$ during the study period. This value is significantly less than those obtained from floating chamber-based experiments performed previously in estuarine environments, but is similar in magnitude to values obtained using the dual tracer method in river and tidal coastal waters and values predicted on the basis of the relationship between the gas exchange rate and wind speed (Wanninkhof 1992), which is generally applicable to the open ocean. Our result is also consistent with the relationship of Raymond and Cole (2001), which was derived from experiments carried out in estuarine environments using $^{222}Rn$ and chlorofluorocarbons along with measurements undertaken in the Hudson River, Canada, using $SF_6$ and $^3He$. Our results indicate that tidal action in a microtidal region did not discernibly enhance the measured $k_{CO_2}$ value.
The Dissecting Aneurysm of the Posterior Inferior Cerebellar Artery with Unusual Clinical Course
Lee, Hyoung-Soo,Lee, Sang-Youl,Rhee, Woo-Tack,Jang, Yeon-Gyu The Korean Neurosurgical Society 2006 Journal of Korean neurosurgical society Vol.40 No.5
The dissecting aneurysms of the posterior cerebral circulation arise most commonly from the vertebral artery and occasionally extend to the posterior inferior cerebellar artery[PICA]. The dissecting aneurysm localized in the PICA without involving the vertebral artery is rare. We present a PICA dissecting aneurysm that had kaleidoscopic clinical course of bleeding, occlusion, and recanalization before the surgery. The patient had serial follow-up angiograms based on significant changes of clinical status. The patient successfully underwent microsurgical trapping with clips for the dissecting aneurysm and showed neurological improvement.
The Incidence of Aneurysmal Subarachnoid Hemorrhage in Youngdong District, Korea
Lee, Hyoung-Soo,Kim, Young-June,You, Seung-Hoon,Jang, Yeon-Gyu,Rhee, Woo-Tack,Lee, Sang-Youl The Korean Neurosurgical Society 2007 Journal of Korean neurosurgical society Vol.42 No.4
Objective : The purpose of this study is to investigate the incidence of aneurysmal subarachnoid hemorrhage (SAH) in Youngdong district for 10 years. Methods : From Jan. 1997 to Dec. 2006, 732 patients (327 males, 405 females, mean age: $54.8{\pm}13.1$ years) with spontaneous SAH were admitted to our hospital. We reviewed the medical records and radiological findings regarding to the ictus of SAH, location and size of the ruptured aneurysms, Hunt-Hess grade and Fisher grade on admission, personal details such as address, age, and sex, and previous history of medical diseases. Results : In these 732 patients, 672 cases were confirmed as aneurysmal SAH. Among them, 611 patients (262 males, 349 females, mean age: $54.9{\pm}13.2$ years) came from Youngdong district. The average crude annual incidence of aneurysmal SAH for men, women, and both sexes combined in Youngdong district was $7.8{\pm}1.7$, $10.5{\pm}2.7$, and $9.1{\pm}2.1$ per 100,000 population, respectively. Because of the problems related to the observation period and geographical confinement, it was suspected that the representative incidence of aneurysmal SAH in Youngdong district should be made during the later eight years in six coastal regions. Therefore, the average age-adjusted annual incidence for men, women, and both sexes combined was $8.8{\pm}1.4$, $11.2{\pm}1.3$ and $10.0{\pm}1.0$, respectively in the coastal regions of Youngdong district from 1999 to 2006. Conclusion : In overall, our results on the incidence of aneurysmal SAH was not very different from previous observations from other studies.
Lee, Yeon-Mi,Kim, Kyung-Tack,Bae, Hye-Min,Lee, Young-Chul,Choi, Sang-Yoon The Korean Society of Ginseng 2010 Journal of Ginseng Research Vol.34 No.2
This study investigated the antioxidant effects of ginseng coffee in L6 muscle cells. Ginseng coffee was prepared by coating and digesting coffee beans with ginseng concentrate. The ginseng coffee water extract potently protected against hydrogen peroxide-induced L6 cell death and adenosine triphosphate reduction in a dose-dependent manner; in fact, these cytoprotective effects were significantly greater than those of normal coffee. However, ginseng coffee did not exhibit significant radical scavenging or catalase-like activity. These results suggest that ginseng coffee might act as a cytoprotective agent in muscles, but that the protective effects are not due to a direct radical-reduction property but rather to another intracellular signaling factor.
적응 뉴로-퍼지 제어기를 이용한 비선형 시스템의 안정화 제어
Lee, In-Yong,Tack, Han-Ho,Lee, Sang-Bae,Park, Boo-Gue 한국정보통신학회 2001 한국정보통신학회논문지 Vol.5 No.4
본 논문에서는 적응 뉴로-퍼지 제어기를 이용하여 비선형 복합시스템 모델의 안정화 제어 방법에 적용한다. 제안된 적응 뉴로-퍼지 제어기는 언어적 퍼지추론, 프로세스의 입출력 데이터를 이용하는 신경회로망, 최적이론 등이 포함된 인공지능을 시스템구조와 파라메터 검증에 필요한 도구로 이용한다. 그 결과 제안된 방법이 이전에 연구되었던 다른 방법보다 아주 높은 인공지능 모델을 제시하였다. In this paper, an stabilization control method using adaptive neuro-fuzzy controller(ANFC) is proposed for modeling of nonlinear complex systems. The proposed adaptive neuro-fuzzy controller implements system structure and parameter identification using the intelligent schemes together with optimization theory, linguistic fuzzy implication rules, and neural networks from input and output data of processes. The results show that the proposed method can produce the intelligence model with higher accuracy than other works achieved previously.