• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2724-2731
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• 2014

As the future national defense plan of government focus on advanced weapon system, military maintenance facility becomes more important. However, military maintenance facility has been managed by director's experience and simple mathematical calculation until now. Thus, the optimization for the management of military maintenance facility is suggested by more scientistic and logical methods in this study. The study follows the procedure below. First, simulation is designed according to the analysis of military maintenance facility. Second, independent variable and dependent variable are defined for optimization. Independent Variable includes the number of maintenance machine, transportation machine, worker in the details of military maintenance facility operation, and dependent variable involves total maintenance time affected by independent variable. Third, warmup analysis is performed to get warmup period, based on the simulation model. Fourth, the optimal combination is computed with evolution strategy, meta-heuristic, to enhance military maintenance management. By the optimal combination, the management of military maintenance facility can gain the biggest effect against the limited cost. In the future, the multipurpose study, to analyze the military maintenance facility covering various weapon system equipments, will be performed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.68-76
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• 2006

We propose a low noise broadband light source (BLS) and investigate a cost-effective wavelength division multiplexing-passive optical network (WDM-PON) for the convergence of broadcasting and data service. The proposed BLS is used for an injection light of wavelength-locked Fabry-Perot laser diodes (F-P LD) and helps the color-free operation of dense WDM-PON (DWDM-PON). In addition, we apply this BLS to a optical source for overlay of digital broadcasting channel on the WDM-PON.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.343-352
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• 2020

Purpose: This study identifies the impact on composition of the firefighting organization, fire command ability, and public opinion operation on organizational citizenship behavior for fire officials to respond to the earthquake disaster, and provides practical implications as basic data for firefighting organizations to cope with the earthquake disaster. Method: Questionnaire survey was performed for 159 fire officials, and the surveyed data was statistically analyzed by using SPSS 22.0 program. Result: First, the results of the verification of the hypothesis showed that the composition of the fire organization, firefield command ability and public opinion operation have a positive impact on organizational citizenship behavior. Second, the relative contribution of independent variables to the dependent variables was identified in the order of composition of fire organization, fire command ability and public opinion operation. Conclusion: The implications of this study suggested from a practical perspective that the government needs to organize firefighting organizations, develop firefield command ability and operate public opinion in advance in order to respond to earthquakes.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.3
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• pp.29-34
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• 2003

This paper describes the effects of sewage amount, temperature, and years in operation on the infiltration rate of a sewage disposal system. The self-purifying sewage disposal system, which is typically used in rural areas, consists of reeds and fine gravel. Water plants are planted on the gravel bed which provides the habitat for microbes. The basic process is that the gravel bed filters incoming sewage. Thus this system requires the smooth flow of sewage through the gravel. However, the efficiency of the disposal system will be lowered if the gravel bed is clogged with sewage sludge. A three year study shows that infiltration rate slows down significantly until the 7th day, depending on the sewage amount and the temperature. After the 7th day, the infiltration rate remains almost constant. In addition, the infiltration rate decreases as the temperature falls. It also decreases as the number of years in operation increase. But there is no significant change in the infiltration rate after the 7th day, independent of the temperature, the sewage amount, and years in operation. In order to take advantage of high infiltration rate, which improves the efficiency of the disposal system in its early stages, having two gravel beds and using them alternatively will be efficient. This operation method is called intermittent load and makes the disposal system last longer. The water plant roots above the gravel bed make the effective filtration possible because they delay accumulation of the sewage sludge and stabilize the filtration ability.

• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.183-192
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• 1992

An advanced load-follow operation mode, Mode K, is presented for the Korean Standardized Nuclear Power Plants. The Mode K utilizes a heavy worth bank dedicated to axial shape control independent of the existing regulating banks. In Mode K, the heavy bank provides a wide range of axial shape control and a monotonic relationship between its motion and the axial shape change, which makes it easy to automate axial shape control. The achievement of full automatic reactor power control both for the reactivity and power shape would reduce the burden due to load-follow operation on the operator. Also, it can accommodate the frequen-cy control, which requires the plant to respond to the unexpected demand. The Mode K design concepts were tested using simulation responses of Yonggwang Units 3&4, the reference plants for the Korean Standardized Nuclear Power Plants. The results illustrate that the Mode K is an adequate operation mode to provide practical load-follow capabilities for the Korean Standardized Nuclear Power Plants.

• Journal of Chest Surgery
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• v.46 no.2
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• pp.117-123
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• 2013

Background: We examined perioperative predictors of sustained sinus rhythm (SR) in patients undergoing the Cox maze operation and concomitant cardiac surgery for structural heart disease. Materials and Methods: From October 1999 to December 2008, 90 patients with atrial fibrillation (AF) underwent the Cox maze operation and other concomitant cardiac surgery. Eighty-nine patients, all except for one postoperative death, were followed-up with serial electrocardiographic studies, 24-hour Holter monitoring tests, and regular echocardiographic studies. Results: Eighty-nine patients undergoing the maze operation were divided into two groups according to the presence of SR. At the time of last follow-up (mean follow-up period, $51.0{\pm}30.8$ months), 79 patients (88.8%) showed SR (SR group) and 10 patients (11.2%) had recurrent AF (AF group). Factors predictive of sustained SR were the immediate postoperative conversion to SR (odds ratio, 97.2; p=0.001) and the presence of SR at the 6th month postoperatively (odds ratio, 155.7; p=0.002). Duration of AF, mitral valve surgery, number of valves undergoing surgery, left atrial dimension, and perioperative left ventricular dimensions and ejection fractions were not predictors of postoperative maintenance of SR. Conclusion: Immediate postoperative SR conversion and the presence of SR at the 6th postoperative month were independent predictors of sustained SR after the maze operation.

• Journal of Korean Neurosurgical Society
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• v.43 no.3
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• pp.143-148
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• 2008

Objective: Postoperative delirium (POD) is characterized by an acute change in cognitive function and can result in longer hospital stays, higher morbidity rates, and more frequent discharges to long-term care facilities. In this study, we investigated the incidence and risk factors of POD in 224 patients older than 70 years of age, who had undergone a neurosurgical operation in the last two years. Methods: Data related to preoperative factors (male gender, >70 years, previous dementia or delirium, alcohol abuse, serum levels of sodium, potassium and glucose, and co-morbidities), perioperative factors (type of surgery and anesthesia, and duration of surgery) and postoperative data (length of stay in recovery room, severity of pain and use of opioid analgesics) were retrospectively collected and statistically analyzed. Results: POD appeared in 48 patients (21.4%) by postoperative day 3. When we excluded 26 patients with previous dementia or delirium, 17 spontaneously recovered by postoperative day 14, while 5 patients recovered by postoperative 2 months with medication, among 22 patients with newly developed POD. The univariate risk factors for POD included previously dementic or delirious patients, abnormal preoperative serum glucose level, pre-existent diabetes, the use of local anesthesia for the operation, longer operation time (>3.2 hr) or recovery room stay (>90 mini, and severe pain (VAS>6.8) requiring opioid treatment (p<0.05). Backward regression analysis revealed that previously dementic patients with diabetes, the operation being performed under local anesthesia, and severe postoperative pain treated with opioids were independent risk factors for POD. Conclusion: Our study shows that control of blood glucose levels and management of pain during local anesthesia and in the immediate postoperative period can reduce unexpected POD and help preventing unexpected medicolegal problems and economic burdens.

• Journal of Gastric Cancer
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• v.11 no.1
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• pp.38-45
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• 2011

Purpose: Bone metastasis from stomach cancer occurs only rarely and it is known to have a very poor prognosis. This study examined the clinical characteristics and prognosis of patients who were diagnosed with stomach cancer and bone metastasis. Materials and Methods: The subjects were 19 patients who were diagnosed with stomach cancer at Hanyang University Medical Center from June 1992 to August 2010 and they also had bone metastasis. The survival rate according to many clinicopathologic factors was retrospectively analyzed. Results: 11 patients out of 18 patients (61%) who received an operation were in stage IV and the most common bone metastasis location was the spine. Bone scintigraphy was mostly used for diagnosing bone metastasis and PET-CT and magnetic resonance imaging were used singly or together. The serum alkaline phosphatase at the time of diagnosis had increased in 12 cases and there were clinical symptoms (bone pain) in 16 cases. Treatment was given to 14 cases and it was mostly radiotherapy. There were 2 cases of discovering bone metastasis at the time of diagnosing stomach cancer. The interval after operation to the time of diagnosing bone metastasis for the 18 cases that received a stomach cancer operation was on average $14.9{\pm}17.3$ months and the period until death after the diagnosis of bone metastasis was on average $3.8{\pm}2.6$ months. As a result of univariate survival rate analysis, the group that was treated for bone metastasis had a significantly better survival period when the bone metastasis was singular rather than multiple, as compared to the non-treatment group, yet both factors were not independent prognosis factors on multivariate survival analysis. Conclusions: An examination to confirm the status of bone metastasis when conducting a radio-tracer test after the initial diagnosis and also after an operation is needed for stomach cancer patients, and bone scintigraphy is the most helpfully modality. Making the diagnosis at the early stage and suitable treatments are expected to enhance the survival rate and improve the quality of life even for the patients with bone metastasis.

• Journal of the Korean Society of Costume
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• v.64 no.5
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• pp.62-75
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• 2014

The importance of VMD operation strategies in fashion business is growing, and this study analyzed the difference in consumers' VMD cognition of the two VMD operation systems: VMD specialist employment system and VMD outsourcing system. Two SPA brands were selected as the representative cases of the two VMD operation systems. A statistical analysis was performed using data collected from a total of 206 university and graduate students from an experimental study. Paired t-test and independent t-test were used for the analysis. The results are as follow: First, consumers' VMD cognition of the two VMD operating systems were different, and the VMD specialist employment system was valued higher than the VMD outsourcing system in all cognition dimensions. Second, the VMD specialist employment system was valued generally higher than the VMD outsourcing system regardless of gender, clothing involvement, and VMD interest of consumers. Third, the VMD specialist employment system was valued higher than the VMD outsourcing system in the following aesthetic aspects: harmony, attractiveness, and fashionable dimensions by the male, low involvement, and the VMD interested consumers. Fourth, the VMD outsourcing system was valued higher than the VMD specialist employment system in the appropriateness and the functionality dimensions by females and the high-involvement consumers, It also scored higher in the fashionable and attractive dimensions by the VMD interested consumers.

• Health Policy and Management
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• v.8 no.1
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• pp.1-14
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• 1998

Analysis of practice variations has been one of important issues in trying to contain costs as well as to manage quality in health care. This study was conducted to provide statistical model for analysing variations in inpatient costs by type of hospitals. Four K-DRGs including Cesarean section, appendectomy, cataract extraction, and pediatric pneumonia with CC class 0 were selected, and means and dispersions of inpatient procedure and operation costs were simultaneously compared between type of hospitals. The results indicated that joint modelling of means and dispersions by gamma distribution was a very useful analytic tool for identifying factors which might have relationship with variations in inpatient costs. This model can be expanded to test the significance of several independent variables in analysing cost variations. In surgical conditions, means and unit variations of procedure and operation costs showed consistent pattern which was tertiarty hospital, general hospital, and hospital in descending order. Different findings were identified in pediatric pneumonia, from which mean and unit variation of procedure and operation cost was the highest in general hospital. The practical implication of this difference could not be drawn from this study. It will be done by further sophisticated researches. In order to develop health policy for cost containment and quality management in Korea, it is essential to find out manageable factors affecting variations in practice patterns which include characteristics of population, providers, regions, and so on. The statistical model presented in this study will give health services researchers useful insights for future investigations in analysing cost variations.