• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.91-94
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• 1996

A simulation procedure was developed for identifying Yungnam unit 2 excitation model parameters to improve the accuracy of stability simulation of KEPCO. First, generator model parameters are derived by using modified load rejection technique from measured load rejection test. For identifying excitation model parameters, switch was changed from MVR mode to AVR mode in Yungnam unit 2 excitation system instead of applying to a small step to the voltage reference($V_{ref}$) because of saving time and efforts, assuming the test result would show coincided result with applying to a small step to the $V_{ref}$. However, it was found that the response of switching from MVR to AVR is greatly different from it of applying small signal to the $V_{ref}$. A simulation procedure was needed to take into accounts of real AVR component status before and after switching from MVR to AVR. This paper reports the procedure which duplicated the measured response and addresses the merits of this test on conventional AVR step test.

• Transactions on Electrical and Electronic Materials
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• v.13 no.1
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• pp.10-15
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• 2012

In conventional, skin detection methods using for skin color definitions is based on prior knowledge. By experimentation, the threshold value for dividing the background from the skin region is determined subjectively. A drawback of such techniques is that their performance is dependent on a threshold value which is estimated from repeated experiments. To overcome this, the present paper introduces a skin region detection method. This method uses a histogram approximation based on the mean shift algorithm. This proposed method applies the mean shift procedure to a histogram of a skin map of the input image. It is generated by comparing with the standard skin colors in the $C_bC_r$ color space. It divides the background from the skin region by selecting the maximum value according to the brightness level. As the histogram has the form of a discontinuous function. It is accumulated according to the brightness values of the pixels. It is then, approximated by a Gaussian mixture model (GMM) using the Bezier curve technique. Thus, the proposed method detects the skin region using the mean shift procedure to determine a maximum value. Rather than using a manually selected threshold value, as in existing techniques this becomes the dividing point. Experiments confirm that the new procedure effectively detects the skin region.

• Smart Structures and Systems
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• v.7 no.4
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• pp.289-302
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• 2011

In marine clay deposits, naturally formed or artificially reclaimed, the evaluation and monitoring of the consolidation process has been a critical issue in civil engineering practices due to the time frame required for completing the consolidation process, which range from several days to several years. While complementing the conventional iconographic method suggested by Casagrande and recently developed in-situ techniques that measure the shear wave, this study suggests an alternative experimental procedure that can be used to evaluate the consolidation state of marine clay deposits using the shear wave velocity. A laboratory consolidation testing apparatus was implemented with bimorph-type piezoelectric bender elements to determine the effective stress-shear wave velocity (${\sigma}^{\prime}-V_s$) relationship with the marine clays of interest. The in-situ consolidation state was then evaluated by comparing the in-situ shear wave velocity data with the effective stress-shear wave velocity relationships obtained from laboratory experiments. The suggested methodology was applied and verified at three different sites in South Korea, i.e., a foreshore site in Incheon, a submarine deposit in Busan, and an estuary delta deposit in Busan. It is found that the shear wave-based experimental procedure presented in this paper can be effectively and reliably used to evaluate the consolidation state of marine clay deposits.

• Clinical Endoscopy
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• v.56 no.6
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• pp.769-777
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• 2023

Background/Aims: Endoscopic submucosal dissection (ESD) for superficial non-ampullary duodenal tumors (SNADETs) is associated with a high rate of en bloc resection. However, the technique for ESD remains challenging. Recent studies have demonstrated the effectiveness of S-O clips in colonic and gastric ESD. We evaluated the efficacy and safety of duodenal ESD using an S-O clip for SNADETs. Methods: Consecutive patients who underwent ESD for SNADETs between January 2011 and December 2021 were retrospectively enrolled. Propensity score matching analysis was used to compare patients who underwent duodenal ESD with the S-O clip (S-O group) and those who underwent conventional ESD (control group). Intraoperative perforation rate was the primary outcome, while procedure time and R0 resection rate were the secondary outcomes. Results: After propensity score matching, 16 pairs were created: 43 and 17 in the S-O and control groups, respectively. The intraoperative perforation rate in the S-O group was significantly lower than that in the control group (p=0.033). A significant difference was observed in the procedure time between the S-O and control groups (39±9 vs. 82±30 minutes, respectively; p=0.003). Conclusions: The S-O clip reduced the intraoperative perforation rate and procedure time, which may be useful and effective in duodenal ESD.

• 한국기계연구소 소보
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• s.9
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• pp.141-151
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• 1982

An iterative procedure for the calculation of the thick axisymmetric boundary layer and wake near the stern of a body of revolution is presented. Procedure consists of the potential flow calculation by a method of the integral equation of first kind and the calculation of boundary layer and wake by a differential me¬thod of the boundary layer theory. Additionally, higher order terms are included in the conventional momentum equations and continuity equation for the consider¬ation of the characteristics of axisymmetric flow different from the one of two dimentional flow and the thick boundary layer. These solutions are matched at the edge of boundary layer and wake. The results obtained by the present me¬thod are compared with the experimental data and it is found that the nominal wake distribution at the propeller plane of a axisymmetric body is in good agree¬ment with the experiment.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.367-374
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• 1997

In panel surveys it is necessary to manage both sampling frame and sample units across time. When sample is updated according to the change of its frame, it should be incorporated in the estimation procedure. This paper derives the bias of the conventional estimator caused by neglecting the change of sample, and provides a bias-adjusted estimator with its variance.

• Journal of Korean Dental Science
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• v.8 no.1
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• pp.41-47
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• 2015

Even though a conventional metal ceramic restoration is widely in use, its laboratory procedure is still technique-sensitive, complex, and time-consuming. A ceramic-pressed-to-metal restoration (PTM) can be a reliable alternative. However, simplified laboratory procedure for a PTM is still necessary. The article is to propose a technique that reduces time and effort to fabricate a PTM with the aid of computer-aided design, computer-aided manufacturing and selective laser sintering technologies.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.49-60
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• 1990

Between Jan. 1962 and Dec. 1988 380 cases of palliative operations were done in 357 patients for congenital heart disease. These includes 55 cases of classic Blalock-Taussig shunt, 212 cases of modified Blalock-Taussig shunt, 17 cases of Glenn shunt, 26 cases of Waterston shunt, 3 cases of Brock procedure, 33 cases of pulmonary artery banding, 6 cases of transpulmonary valvotomy, 4 cases of unifocalization, and 10 cases of open atrial septectomy. We divided the operative procedures into the conventional and the unconventional. Under the unconventional procedures, the cases since April, 1986 were only included. The number of patients who died within the early 30 days after operation is the following: 40 in systemic-pulmonary shunts, 2 in Brock procedure, 12 in PAB, 15 in unconventional procedures. The age of the patients who need palliative operation is lowering more and more and their characteristics of the disease is being transferred to the more complexities. So the role of palliative surgery in the congenital heart disease is changing.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.60-64
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• 2001

In this paper, a new learning methodology for Kernel Methods is suggested that results in a sparse representation of kernel space from the training patterns for classification problems. Among the traditional algorithms of linear discriminant function(perceptron, relaxation, LMS(least mean squared), pseudoinverse), this paper shows that the relaxation procedure can obtain the maximum margin separating hyperplane of linearly separable pattern classification problem as SVM(Support Vector Machine) classifier does. The original relaxation method gives only the necessary condition of SV patterns. We suggest the sufficient condition to identify the SV patterns in the learning epochs. Experiment results show the new methods have the higher or equivalent performance compared to the conventional approach.

• Industrial Engineering and Management Systems
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• v.7 no.2
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• pp.182-188
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• 2008

Automated parking systems, which automatically park and retrieve vehicles, have been steadily replacing conventional parking systems. The spiral parking system is a type of automated parking systems that has cylindrical parking tower. We develop an economic design model of spiral parking system based on a recursive optimization and simulation procedure in which the dynamic nature of the parking system can be integrated into the mathematical programming model. The optimal values of design parameters are found that gives the minimum total cost while complying with the desired performance of the system.