• 한국경영과학회지
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• 제30권2호
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• pp.41-61
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• 2005

The concept of revenue management (RM) has been used widely in the air-transportation industry, and proven as a good system for managing perishable assets. While the airlines are the oldest and most sophisticated users of RM, these practices have been an enormously important innovation in other service industries such as the travel, the railway, the internet and the manufacturing industries. In this paper, reviewing several studies on RM, we introduce the fundamental concepts and the major models of RM covering seat allocation with multiple fare classes and overbooking. Future research directions also are suggested.

• Journal of Korean Neurosurgical Society
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• 제54권6호
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• pp.525-527
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• 2013

Upward migration of the peritoneal catheter of a subgaleo-peritoneal (SP) shunt and coiling into the subgaleal space is an extremely rare complication of a SP shunt. A 32-year-old male patient visited our hospital presenting with a large skull defect due to a prior craniectomy performed elsewhere. The patient underwent a cranioplasty with methylmetacrylate, but subsequently developed progressive pseudomeningocele and subgaleal cerebrospinal fluid (CSF) collection. The patient underwent CSF diversion via a SP shunt. After SP shunting, the pseudomeningocele disappeared completely. Six months later, the patient presented with progressive scalp swelling. Skull X-ray showed migration and coiling of the distal catheter of the SP shunt. The patient was treated by removing the entire shunt catheter and the dura was covered with a subgaleal flap. We would like to report our experience with a very rare complication of subgaleo-peritoneal shunting.

• Journal of Trauma and Injury
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• 제30권2호
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• pp.55-58
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• 2017

Standard open procedures for resection of the first rib in thoracic outlet syndrome can prove to be quite difficult with extensive incisions. A minimal invasive procedure can also be painstaking, but provides an attractive alternative to the more radical open procedures. We report the details of the technique with direct video footage of the procedure performed in a 41-year-old man with thoracic outlet syndrome done entirely by thoracoscopic methods.

• 한국항공운항학회지
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• 제25권3호
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• pp.81-88
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• 2017

Aircraft maintenance failure doesn't only threaten flight safety but also causes significant economic losses such as flight delays, flight cancellations, air turn backs and diversion and so on. Therefore, the efforts should be made to detect the contributing factors that cause such maintenance failure and eliminate them. In this study, by analyzing factors contributing to system failure using the Maintenance Error Decision Aid (MEDA) model based on stochastic relations between the contribution factors, system failure and events, we will draw a improvement plan to aircraft maintenance defects.

• 한국농공학회지
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• 제32권3호
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• pp.67-78
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• 1990

A decision support system, Daily Irrigation Network Operation Simulation model (DINOPS) was developed that can adequately describe the physical behavior of an irrigation system. The model is to depict the physical features of complex water allocation schemes of the irrigation system and to simulate the response of the system to different irrigation schemes. The model was validated on the Banweol irrigation district by comparing the simulated canal discharges and paddy water levels with the field data. The operation of the DINOPS model was demonstrated on the irrigation district where several irrigation management practices were evaluated with computing irrigation efficiencies and rainfall effectiveness respectively. The model sensitivity with respect to heights of bund and block diversion rates were analyzed and discussed.

• 유통과학연구
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• 제14권5호
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• pp.27-37
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• 2016

Purpose - Prior theories expect a lower marginal value of cash for weak governance firms. To test this hypothesis, we examine the relationship between corporate governance structures and marginal cash values in Korean retail firms. Research design, data, and methodology - We estimate marginal cash values based on the model of Faulkender & Wang (2006). The retail firms listed in Korean Stock Exchange from 2005 to 2013 are analyzed. Corporate governance scores are provided by Korean Corporate Governance Services. Results - We show a higher marginal value of cash for the weak governance retail firms in terms of total governance score. Our analysis on a detailed set of governance scores generally confirms this tendency. Yet, a higher marginal cash value is obtained for the firms with better board structures and dividend policies. Conclusions - Our findings argue against the agency view of cash policy predicting a negative relationship between corporate governance scores and marginal cash values. A low marginal value of cash, widely observed in the sample firms, also supports severe resource diversion problem in Korean corporations.

• Journal of Korean Neurosurgical Society
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• 제55권6호
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• pp.375-378
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• 2014

Hydranencephaly is a rare congenital disease defined as an absence of cerebral hemispheres with an intact thalamus, brain stem, and cerebellum. Generally, patients with hydranencephaly require cerebro-spinal fluid diversion due to progressive hydrocephalus. An excellent view of the choroid plexus and advancement of the neurosurgical endoscope were possible, leading to easy coagulation of the choroid plexus to balance cerebro-spinal fluid production without the use of a shunt device. We present this rare case and good treatment outcome from endoscopic coagulation of the choroid plexus.

• 유통과학연구
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• 제10권12호
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• pp.13-17
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• 2012

Purpose - The Asia-Pacific Economic Cooperation (APEC) forum has evolved and is actively facilitating free and open trade. It is debated whether APEC has effectively reduced trade barriers in a preferential manner to encourage liberalized trade and whether increased trade between member countries has reduced trade with nonmember countries. Research designs, data, methodology -This paper empirically tests whether APEC creates or diverts trade, using an extended gravity model with tariff rates, exchange rates, and dummy variables to analyze how APEC affects intra-trade between members.The model utilizes the annual panel data between 1990 and 2007 of 16 selected APEC members and nonmembers. Results - Results reveal the changing role of APEC only between 2002 and 2007 has it created trade, fostering increased trade among trading partners and between members and nonmembers. Conclusion - APEC can be expected to demonstrate a stronger trade creating effect once its advanced and developing members complete tariff reductions by 2010 and 2020, respectively.

• 한국관개배수논문집
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• 제18권2호
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• pp.142-160
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• 2011

This study was performed to apply the preventive management technique that is known for more economic and preventive for disaster than corrective technique to Repair & Improvement(R&I) Project policy of irrigational facilities. The appropriate periods of R&I Project had been driven to 40yrs, 24yrs, 27yrs, and 29yrs for reservoir, Pumping and drainage pumping station, Diversion weir and Irrigation & drainage canal respectively. The cost of R&I Project for 10 years had been estimated as 616.9 billion won per year including the 85 billion won for the project of 'Disaster prevention and Function continuity'. After the period of 'Improvement all at once', about 30yrs, 421.8 billion won was requested for 'Function continuity'.

• Journal of Chest Surgery
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• 제27권7호
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• pp.598-602
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• 1994

We have experinced 20 cases of esophageal perforation from April, 1987 to August, 1993 at ourdivision of Thoracic and Cardiovascular Surgery, Korea University, Gu Ro Hospital. Here we investgates the causes of disease, symptoms and sign, locations, time lag from onset, treatment of perforation and the results.The ratio between male and female patients was 12: 8, and age ranged from 4 years to 70 years old.The cause of esophageal perforation were instrumental trauma 7 cases, stab wound 4 cases, foreign body 4 cases, spontaneous perforations 3 cases, and others 1 cases. The middle and lower portions of esophagus was frequently involved portion in our cases [11 cases of 20].The common complications after perforation were mediastinitis [6 cases] and empyema [2 cases].The method of treatment were as follows, primary repair of perforation, simple drainge techniques including simple cervical drainage and closed thoracostomy, diversion and two-staged operations during several months. There was no mortality in our cases.