시간지연을 갖는 적분 시스템의 PID 제어기 동조법

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.

Mutation of K-ras Oncogene in Thyroid Tumor Tissue

Lee, Jai Hak,Lee, Jong Seo,Kim, Seung Nam,Chang, Suk Kyun,Yoo, Seung Jin,Song, Young Tack,Cho, Won Il,Choo, Sang Yong CATHOLIC MEDICAL CENTER 1993 Bulletin of the Clinical Research Institute Vol.21 No.1

Point mutation of oncogene, one of the genetic alteration in cancer development, has been found in many malignant tumor tissues, Among those malignant tumors, the incidence of point mutation of K-ras oncogene was reported over 90% in pancreatic cancers, 40-50% in colotectal cancer, 25-30% in lung cancers and less than 10% in urogenital, breast or cervical cancers. Several investigators have reported the incidence of point mutation of ras oncogene was 30-50% in benign thyroid tumors and 50-80% in malignant thyroid tumors with some difference by tumor cell differentiation. Also some reports suggested ras mutation may constitute early steps in thyroid tumorigenesis. But there if few report about relation between point mutation and characteristics of mutation. In order to find out the incidence of k-ras oncogene point mutation and relation with characteristics of mutation in thyroid tumors, authors isolated DNA from each 10 normal tissue and benign and malignant tumor tissues. And then, point mutations of K-ras oncogene (four characteristics of codon 12 and one characteristic of codon 13) were detected by paired PCR with mutation-specific primer and agarose gel electrophoresis methods. The resets are as follows; 1. Any mutation was not detected in normal thyroid tissues. While point mutations were detected 7/10 cases (70%) of benign thyroid tumor tissues and in 9/10 cases (90%) of malignant tumor tissues. 2. The incidence of GGT-AGT mutation was highest in benign thyroid tumors (60%) and lowest in malignant thyroid tumors (30%). The incidences of GGT-GAT, TGT-GTT and GGC-GAC mutations were high in malignant tumors (60%). 3. There were 8/9 cases (89%) in malignant tumors and 5/7 cases (71%) in benign tumors of positive mutations over two Hinds of mutation. And also 5/9 cases (56%) of malignant tumors and 4/7 case (51%) of benign tumors expressed positive mutations over 3 kinds. Moreover two cases of each benign and malignant turners expressed all of five mutations. With above result, authors proposed that high incidence of point mutation of k-ras oncogene was detected in benign (70%) and malignant (90%) thyroid turners, and especially high incidence of GGT-AGT mutation (60%,) in benign tumors while high incidence of GGT-GAT, TGT, GTT and GGC-GAC mutations(60%) in malignant turners were noted. Also authors suggested that the point mutation may constitute early steps of thyroid tumorigenesis.

Changes of Hepatic Function and Structure in Experimental Panperitonitis of Rat

Lee, Chul,Song, Young Tack,Lee, Yong Kak CATHOLIC MEDICAL CENTER 1983 Bulletin of the Clinical Research Institute Vol.11 No.1

For the purpose of evaluating the effects of panperitonitis on hepatic function and structure, the experimental animals were sacrificed at 36 hours after operation to check the blood chemistry, aerobic and anaerobic bacterial culture, liver biopsy for light and electron microscopic examination. The results were as follows; 1. In experimental panperitonitis, the causative aerobic bacteria were Escherichia coli (65%), Protons (25%), Staphylococcus aureus (25%), and Peptostaphy-lococcus (95%) was causative annaerobic bacteria. 2. The blood urea nitrogen (BUN), SGOT, SGPT were significantly increased and blood sugar, total protein, serum albumin were significantly decreased in group Ⅱ compare to group Ⅰ(p<0.01). 3. The light microscopic examination showed marked Kupffer cell hyperplasia (95%), portal triaditis (80%), hydropic changes of the hepatic cell (80%), congestion of the vein and sinusoid (75%), capsulitis (60%) in group Ⅱ. 4. The elctron microscopic examination showed mitochondrial swelling, dilated bile canaliculi, decreased and flattening of the microvilli in the bile canaliculi, increased lipocytes, fatty infiltration in the hepatic cell, irregular nuclear surface, segregated nucleoli in group Ⅱ.

Control of Flexible Joint Robot Using Direct Adaptive Neural Networks Controller

Lee, In-Yong,Tack, Han-Ho,Lee, Sang-Bae,Park, Boo-Kwi Korean Institute of Intelligent Systems 2001 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.1 No.1

This paper is devoted to investigating direct adaptive neural control of nonlinear systems with uncertain or unknown dynamic models. In the direct adaptive neural networks control area, theoretical issues of the existing backpropagation-based adaptive neural networks control schemes. The major contribution is proposing the variable index control approach, which is of great significance in the control field, and applying it to derive new stable robust adaptive neural network control schemes. This new schemes possess inherent robustness to system model uncertainty, which is not required to satisfy any matching condition. To demonstrate the feasibility of the proposed leaning algorithms and direct adaptive neural networks control schemes, intensive computer simulations were conducted based on the flexible joint robot systems and functions.

Prediction of Cement Volume for Vertebroplasty Based on Imaging and Biomechanical Results

Lee, Sung-Jae,Tack, Gye-Rae,Lee, Seung-Yong,Jun, Bong-Jae,Lim, Do-Hyung,Shin, Jung-Woog,Kim, Jeong-Koo,Shin, Kyu-Chul The Korean Society of Mechanical Engineers 2001 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.15 No.7

Control of bone cement volume (PMMA) may be critical for preventing complications in vertebroplasty, the percutaneous injection of PMMA into vertebra. The purpose of this study was to predict the optimal volume of PMMA injection based on CT images. For this, correlation between PMMA volume and textural features of CT images was examined before and after surgery to evaluate the appropriate PMMA amount. The gray level run length analysis was used to determine the textural features of the trabecular bone. Extimation of PMMA volume was done using 3D visualization with semi-automatic segmentation on postoperative CT images. Then, finite element (FE) models were constructed based on the CT image data of patients and PMMA volume. Appropriate material properties for the trabecular bone were assigned by converting BMD to elastic modulus. Structural reinforcement due to the changes in PMMA volume and BMD was assessed in terms of axial displacement of the superior endplate. A strong correlation was found between the injected PMMA volume and the area of the intertrabecular space and that of trabecular bone calculated from the CT images (r=0.90 and -0.90, respectively). FE results suggested that vertebroplasty could effectively reinforce the osteoporotic vertebra regardless of BMD or PMMA volume. Effectiveness of additional PMMA injection tended to decrease. For patients with BMD well lower than 50mg/ml, injection of up to 30% volume of the vertebral body is recommended. However, less than 30% is recommended otherwise to avoid any complications from excessive PMMA because the strength has already reached the normal level.

Changes of Hepatic Function and Structure in Experimental Panperitonitis of Rat

Lee, Chul,Song, Young-Tack,Lee, Yong-Kak Catholic Medical Center 1983 Bulletin of the Clinical Research Institute Vol.11 No.-

Panaxydol Derived from <i>Panax ginseng</i> Inhibits G₁ Cell Cycle Progression in Non-small Cell Lung Cancer <i>via</i> Upregulation of Intracellular Ca²⁺ Levels

Lee, Jeong-Hun,Leem, Dong Gyu,Chung, Kyung-Sook,Kim, Kyung-Tack,Choi, Sang Yoon,Lee, Kyung-Tae Pharmaceutical Society of Japan 2018 Biological & pharmaceutical bulletin Vol.41 No.11

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.

Gas Exchange Rates Measured Using a Dual-Tracer ($SF_6$ and $^3He$) Method in the Coastal Waters of Korea

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.

Prediction of Surface Ocean $pCO_2$ from Observations of Salinity, Temperature and Nitrate: the Empirical Model Perspective

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 $pCO_{2SEA}$.