• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.1-15
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• 2008

The purpose of this study is to propose a procedure that will be able to find the most efficient sets of weight coefficients for the Geum-River basin in Korea. The result obtained from multi-objective optimization model is inherently sensitive to the weight coefficient on each objective. In multi-objective reservoir operation problems, the coefficient setting may be more complicated because of the natural variation of inflow. Therefore, for multi-objective reservoir operation problems, it may be important for modelers to provide reservoir operators with appropriate sets of weight coefficients considering the inflow variation. This study presents a procedure to find an appropriate set of weight coefficients under the situation that has inflow variation. The proposed procedure uses GA-CoMOM to provide a set of weight coefficient sets. A DEA-window analysis and a cross efficiency analysis are then performed in order to evaluate and rank the sets of weight coefficients for various inflow scenarios. This proposed procedure might be able to find the most efficient sets of weight coefficients for the Geum-River basin in Korea.

• Journal of Chest Surgery
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• v.39 no.10 s.267
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• pp.765-769
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• 2006

Background: Nuss procedure is a minimally invasive technique for correcting the pectus excavatum. But there are some limitations of correcting the complex anomaly or grown-up patients. Material and Method: we retrospectively reviewed 135 consecutive patients who underwent repair of pectus excavatum by the Nuss procedure and its modifications between November 1999 and December 2004. We analyzed the computed tomography, age on operation, operative technique, and complications. Result: We operated 135 patients of pectus excavatum during 62 months. Total number of operations about Nuss procedure is 216, including bar removal procedure of 64 cases, redo Nuss procedures of 47 cases. We modified the point of bar insertion to the hinge point, made a shoulder in the bar to prevent a displacement. And then we changed the fixation material from Vicryl to steel wire. If the patients are old, we retract the sternum during bar rotation and fixation. Until 2002, the number of redo Nuss operations were 17, complications were 23. but, after modifications, the number of redo Nuss operation were 0, complications were 2. Conclusion: This result indicates that our modifications of Nuss operation is effective, and could decrease the number of redo Nuss operation and complications.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.72-75
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• 2004

The Fontan operation is commonly practiced for the physiologic correction of univentricular heart diseases. However, for the patients who have risk factors against this operation, it is recommended to take the initial palliative operation rather than going to the Fontan operation at once. The proper timing to the Fontan operation after palliation is decided by assessing several factors such as patient's age and other risks of maintaining palliative state, etc. Usually, the Fontan operation is done relatively early after palliation stage. Here, we report a 36 years old-adult-female with univentricular heart disease who underwent the successful Fontan operation at 17 years after unidirectional Glenn procedure.

• Journal of the Ergonomics Society of Korea
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• v.7 no.2
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• pp.31-44
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• 1988

If an error occurs in the automatic mode when the advanced teleoperator system performs a task in hostile environment then the automatic mode changes into the manual mode. The operation by the control program and the operation by a human recover the error in the manual mode. The system resumes the automatic mode and continues the given task. It is necessary to improve the manual mode in order to make the best use of a man-robot system, as a part of the human interface technique. Therefore, the error recovery task is performed by combining the operation by the control program representing autonomy of a robot and the operation by a human representing versatility of a human operator effectively in the view point of human factors engineering. The geometric inverse kinematics is used for the calculation of the robot joint values in the operation by the control program. The singularity operation error and the parameter operation error often occur in this procedure. These two operation errors increase the movement time of the robot and the coordinate reading time, during the error recovery task. A singularity algorithm, parameter algorithm and fuzzy control are studied so as to remove the disadvantages of geometric inverse kinematics. And the geometric straight line motion is studied so as to improve the disadvantages of the operation by a human.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.292-297
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• 2016

Since continuous descent operations (CDO) is one of several tools available to aircraft operators and air navigation service providers (ANSPs) to increase safety, flight predictability, and airspace capacity while reducing noise, controller-pilot communications, fuel burn and emissions, widespread implementation of CDO would result in significant reductions in the environmental impact and aircraft operation costs in south korea as well. After analyzing each procedure from standard terminal arrival routes used for the Incheon international airport, it can be noticed that one of the procedures has a relatively high altitude constraint at initial approach fix than others, which lead the pilots to use unnecessary drag device in certain situations. Therefore we came to a conclusion that some arrival procedures need to be revised, so unnecessary procedure required during approach can be minimized, thereby reducing fuel consumption, noise and emissions compared to current approach procedures. And it is going to increase the safety margin significantly during approach phase due to reduced workload.

• Journal of Chest Surgery
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• v.46 no.2
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• pp.98-103
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• 2013

Background: Atrial fibrillation (AF) is a common complication in elderly patients with atrial septal defect (ASD). The purpose of this study was to examine the efficacy of the maze procedure in these patients. Materials and Methods: Between February 2000 and May 2011, 46 patients underwent the maze procedure as a concomitant operation with ASD closure. Three patients who underwent a right-sided maze were excluded, and one patient was lost to follow-up. The mean follow-up duration was $3.2{\pm}2.5$ years. Electrocardiography was performed 1 month, 3 months, 6 months, and 1 year after surgery, and checked annually after that. Results: AF persisted in 4 patients after surgery. One year after surgery, among 38 patients, 55.3% remained in sinus rhythm without antiarrhythmic drugs. However, when including the patients who took antiarrhythmic drugs, 92.1% were in sinus rhythm. Freedom from AF recurrence at 3 months, 6 months, 1 year, 2 years, 3 years, and 5 years after surgery were $97.4{\pm}2.6$, $94.4{\pm}3.8$, $91.2{\pm}4.9$, $87.8{\pm}5.8$, $79.5{\pm}7.6$, and $68.2{\pm}12.4$, respectively. There was no early mortality after operation. Conclusion: Concomitant treatment with the maze procedure and ASD closure is safe and effective for restoring the sinus rhythm.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.3
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• pp.200-210
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• 2019

High-speed planing craft is generally smaller than commercial vessels, for which not only the roll motion but also the pitch and heave motions are relatively large during operation However, if seakeeping performance of high-speed planing craft is evaluated by assessment methods of commercial vessels considering roll damping only, it would get unreasonable results due to excessive magnitudes of motion. This research aims at developing a procedure to evaluate seakeeping performance of high-speed planing craft reasonably well by considering responses of roll, heave and pitch motions. In addition, we tried to combine advantages of the potential flow method and CFD in this procedure, a so-called hybrid method, which uses the 3D panel method for the analysis of seakeeping performance, and tunes the damping coefficient using CFD analysis at a specific frequency. Finally, we evaluated seakeeping performance of coastal rescue boat in operation by applying the proposed procedure, and analyzed the results referring to the seakeeping criteria.

• Journal of Chest Surgery
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• v.12 no.1
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• pp.67-74
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• 1979

Esophagocardiomyotomy [modified Heller procedure] is a widely accepted operation for relief of dysphagia in patient with esophageal achalasia. But patients with advanced achalasia were more likely to get poorer results from a modified Heller myotomy because of the dependent pouch that creates an angulation at the junction of thick-walled dilated esophagus with the thin wailed aganglionic segment and hinders complete emptying. Thorbjarnarson[1975] proposed the method including truncal vagectomy and pyloroplasty. Vagectomy and pyloroplasty should lesson the severity of acid-peptic esophagitis, if reflux should occur postoperatively. Here we presented 4 cases esophageal achalasia treated by modified Heller operation of 3 cases and one case of Thorbjarnarson method. All postoperative results are good.

• Journal of Chest Surgery
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• v.27 no.9
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• pp.808-811
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• 1994

We reported a successful right pneumonectomy using video assisted thoracoscopy for endobronchial tuberculosis. Thoracoscopic surgery has many advantages in spite of its technical difficulties. These advantages include good cosmetic effects, short hospital stay, decreased postoperative morbidity, and good postoperative pulmonary function.The patient was young unmarried female, and her right lung was nearly total obstructed by endobronchial tuberculous dissemination and secondary pulmonary infection. The procedure was a little complicated by inadequate placements of the thoracoscopic ports and 5cm length utility thoracotomy incision. Minimal pain killer was needed only two days after operation and scar of operative wound was very satisfying. Postoperative course was unusual and the patient was discharged 7 days after operation.

• Journal of Chest Surgery
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• v.20 no.4
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• pp.829-838
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• 1987

Bronchopulmonary sequestration is a rare congenital malformation of the lung, concerning about the abnormal feeding systemic artery, may happen a serious complication of heeding during operation if not recognized before operation. High index of suspicion of sequestration is the key to successful operative procedure with the aid of characteristic recurrent and long-standing symptoms, its location, and invasive or non-invasive diagnostic tools. We report 2 cases of intralobar type of bronchopulmonary sequestration and review 10 articles about the subject, totaling of 21 cases.