• International Journal of Highway Engineering
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• v.12 no.1
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• pp.39-46
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• 2010

Delineator is a useful device to support driver's safer maneuver. Effective placement and operation of the delineator would lead to prevent traffic accidents on the roads. This study evaluates the effectiveness of parameters associated with delineator placement and operation, which include spacing, height and size, from the point of user's satisfaction. Also, this study devises a methodology for determining such parameters using binary logistic regression technique. The proposed model is capable of producing probabilistic measure of user's satisfaction according to the various parameters. The outcome of this study would be useful fundamentals for more effective placement and operation of delineators.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.82-88
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• 2013

It is important to give lightning warning prior to a cloud-to-ground (CG) discharge within an Area of Concern (AOC) because most of lightning damage and victim are usually occurred by the first lightning in the AOC. The aim of this study is to find the optimal operation conditions of the automated lightning warning systems in order to make the best use of the available data. In this paper, the test-operated results of the automated lightning alert and risk management system (ALARM) based on detections of CG discharge and eletrostatic field and optimized at probability of lightning have been described. It was possible to obtain the following warning performance parameters: probability of detection (POD), false alarm ratio (FAR), probability of lightning (POL) and failure-to-warn rate (FTW). The data obtained from trial operation for 5months were not sufficient but the first analysis of domestic lightning warning was carried out. We have observed that the evaluated statistical results through trial operation depend on the various factors such as analysis methods and criteria, topographical conditions, etc. Also we suggest some methods for improvement of POL and POD including the finding of the optimal electric field threshold level to be used, based on the high values of FAR and FTW found in this work.

• Journal of Navigation and Port Research
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• v.40 no.4
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• pp.165-171
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• 2016

SEEMP (Ship Energy Efficiency Management Plan) has entered into force since 2013 for the reduction of GHG emission of operating ships. SEEMP guidelines include the hardware modification or installation of energy-saving device on ship. It also includes software based energy-saving technology such as optimum routing, speed optimization, etc. Hardware based technologies are not easy to apply to ongoing vessel due to the operational restriction. Therefore, IT based energy-saving technology was applied and its energy efficiency was evaluated using before and after energy-saving system applied voyage data. SEEMP advises a voluntary participation of EEOI (Ship Energy Efficiency Operation Indicator) use as an indicator of ship energy efficiency operation, and those results were also shown to evaluate the improvement efficiency of energy-saving system.

• 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.

• Advances in pediatric surgery
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• v.17 no.1
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• pp.35-44
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• 2011

Thyroglossal duct cysts (TGDC) are the most common type of congenital developmental anomaly encountered in the anterior midline of the neck in childhood. The aim of the study was to evaluate the clinical characteristics of TGDC and identify any factors that could be related to recurrence after surgery. This study consisted of a retrospective chart review of 45 patients treated at Kyungpook National University Hospital for TGDC between 1990 and 2008. All records were reviewed for age and sex, length of history, presentation, diagnostic methods, sizes and locations of cyst, surgical management, histopathology of the lesion and recurrences. The statistical analysis of risk factors for recurrence was made using the Fisher's exact test with a significance level of p (0.05. The male to female ratio was 2.2:1 with a male preponderance. The mean age at operation was 5 years and 2 months (4 months - 17 years). The most common presenting symptom was a nontender cervical mass (78 %). Most TGDC were found in the midline position. Twenty four were infrahyold, 17 were hyoid, and 4 were suprahyoid level. Forty one (91 %) patients received the Sistrunk operation, and 4(9 %) patients received Cyst excision. Postoperative a seroma developed in six patients in the early postoperative days. There were a total of 3(6.6 %) recurrences, 2 in patients who had excision only and in one patient who had the Sistrunk operation. Univariate analysis for risk factors with recurrence showed that there was no statistical relationship between the presence of preoperative infection and the development of recurrence. The removal of hyoid bone along with TGDC was a statistically significant risk factor for recurrent disease. This study suggests that the Sistrunk operation Is the treatment of choice for TGDC in order to reduce recurrence.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.2
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• pp.125-130
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• 2009

For many years, intermaxillary fixation using arch bar has been operated in treatment of mandibular fracture patients. But it has many complications including injury of operators and assistants cause by wire, inflammation of periodontium. For that reasons alternatives are required; osteosynthesis technique using mini plate, intermaxillary fixation using IMF screws have been available. Treatment by arch bar fixation, however, is still valuable to treat craniomaxillary fracture patients. The purpose of this study is to know effect arch bar on periodontium and influence gingival gel on periodontium applied by arch bar. 40 mandibular fracture patients are monitored. 30 patients were applied by arch bar, 10 patients were not. And the former were classified by 3 categories; Nano vitamin and Mastic gel were applied to 10 patients respectively and any gingival gel was not used to 10 patients. Clinical attachment level, bleeding on probing and periodontal depth of each group were measured and compared before operation and on 2 weeks and 6 weeks after operation. Mann-Whitney U test was used to analyze result which leads to this conclusion. 1. Whether arch bar is applied or not, treatment of mandlbular fracture gave rise to gingivitis, but 6 weeks after operation, gingivitis is restored to the same level as the state before operation. 2. More severe gingivitis appeared when arch bar is applied to mandibular fracture than when it is not. 3. Both gingival gel used in this study can reduce gingivitis which can be caused by arch bar. 4. In this study, Mastic gel is more effective for prevent gingival inflammation cause by arch bar than nano vitamin. In regard to this result, gingivitis is considered to be available because it is reversible and does not induce periodontal disease. Gingival gel is regarded to be helpful for patients applied by arch bar to feel less discomfort.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.364-367
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• 2013

In this paper, we propose a method about reducing facial blemishes using Morphological Operation. First, we detect skin region using pixel data of RGB's each channel image. we create histogram of skin region R, G, B channel and save 3 pixel values that are high frequency pixel value in each channel. After than, we find facial blemishes using Black-hat operation. The pixel value of facial blemishes changes average of its pixel value, 8-neighborhood pixel value and high frequency pixel values. And the facial blemishes pixel is blurred with median filter. The result of this test with facial pictures that have facial blemishes, we prove that this system that correct the face skin using reduction facial Blemishes is more efficient method than correct the face skin just using lighting up.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.171-177
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• 2012

In this paper, we proposed a algorithm and an operation boundary for fault detection of a onboard GNSS receiver. After aircraft exchange corrections computed by an aircraft receiver, a faulty aircraft receiver is detected by checking consistency of correction. For this purpose, PRC residual is used as the test statistic for fault detection of the onboard GNSS receiver. And operation boundaries are set by using DGPS position error increase with respect to the distance from a reference station. If the fault detection is performed by using aircraft only in operation boundary, the more accurate fault detection can be possible.

• Journal of Welding and Joining
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• v.28 no.1
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• pp.41-46
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• 2010

The low alloy-steel material(1.0Cr-0.5Mo, SA213T12), which has widely been used for the waterwall tube in the conventional power plant, do not have enough creep rupture strength for waterwall tubes of the Ultra-supercritical(USC) boilers. According to this reason, the high-strength low alloy-steel(2.25Cr-1.0Mo, SA213T22) has newly been adopted for the waterwall tube in the USC boilers. This paper presents failure analysis on weld-joint of the waterwall tubes in USC boilers. Visual inspections were performed to find out the characteristics of the fracture. Additionally both microscopic characteristics and hardness test were carried out on failed tube samples. Failures seem to happen mainly because the welding process has not been conducted strictly.(preheating, P.W.H.T and so forth). Thus, this paper has the purpose to describe the main cause of the poor welding process and to explain how to prevent similar failures in those weld-joints.