• 대한안전경영과학회지
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• 제12권1호
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• pp.199-205
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• 2010

The research proposes the three-factor random measurement models for estimating the precision about operator, part, tool, and various measurement environments. The combined model with crossed and nested factors is developed to analyze the approximate F test by degrees of freedom given by Satterthwaite and point estimation of precisions from expected mean square. The model developed in this paper can be extended to the three useful models according to the type of nested designs. The study also provides the three-step procedures to evaluate the measurement precisions using three indexes such as SNR(Signal-To-Noise Ratio), R&R TR(Reproducibility&Repeatability-To-Total Precision Ratio), and PTR(Precision-To-Tolerance Ratio), The procedures include the identification of resolution, the improvement of R&R reduction, and the evaluation of precision effect.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권10호
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• pp.1751-1768
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• 2011

Falls are one of the most concerned accidents for elderly people and often result in serious physical and psychological consequences. Many researchers have studied fall detection techniques in various domain, however none released to a commercial product satisfying user requirements. We present a systematic modeling and evaluating procedure for best classification performance and then do experiments for comparing the performance of six procedures to get a statistical classifier based wrist-type fall detector to prevent dangerous consequences from falls. Even though the wrist may be the most difficult measurement location on the body to discern a fall event, the proposed feature deduction process and fall classification procedures shows positive results by using data sets of fall and general activity as two classes.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.181-206
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• 2022

This paper presents experimental modal analysis and static load testing results to validate the accuracy of dynamic parameters-based damage locating indices in RC structures. The study investigates the accuracy of different dynamic-based damage locating indices compared to observed crack patterns from static load tests and how different damage levels and scenarios impact them. The damage locating indices based on mode shape curvature and mode shape fourth derivate in their original forms were found to show anomalies along the beam length and at the supports. The modified forms of these indices show higher sensitivity in locating single and multi-cracks at different damage scenarios. The proposed stiffness reduction index shows good sensitivity in detecting single and multi-cracks. The proposed anomalies elimination procedure helps to remove the anomalies along the beam length. Also, the adoption of the proposed weighting method averaging procedure and normalization procedure help to draw the overall crack pattern based on the adopted set of modes.

• Journal of Oral Medicine and Pain
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• 제42권2호
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• pp.44-48
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• 2017

Chronic temporomandibular joint dislocation is defined as an acute dislocation that cannot be reduced or that recurs for more than one month. The management of dislocation depends on patient status and the duration of dislocation and ranges from conservative reduction to a surgical approach. In the present cases, a 64-year-old male was referred to our department for treatment of chronic dislocation for 6 weeks. The dislocation might be occurred by endotracheal intubation. A 70-year-old female was referred to our department with repeat right condyle dislocation after reduction of dislocation at a local clinic. When she visited for later treatment of new dentures, her condyle had been dislocated again for several weeks. In both cases, we tried to treat the dislocation with several manipulations, which were unsuccessful. Finally, chronic dislocation was successfully treated by surgical traction under general anesthesia without relapse. Surgical traction is a simple, effective option with the lowest morbidity of surgical procedures for chronic dislocation when conservative reduction is unsuccessful.

• 대한두개안면성형외과학회지
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• 제9권1호
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• pp.8-11
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• 2008

Purpose: The majority of nasal bone fractures have been managed by routine procedure of closed reduction, intranasal packing or intranasal Kirschner wire (K-wire) splinting. But it leaves rooms for many complaints from patients such as pain, rhinorrhea and nasal obstructioon. Another option is, of course, no packing at all. The study was initiated to assess the necessity to pack or splint the nasal bone after routine closed reduction. Methods: We analysed the medical records of 35 patients with nasal bone fracture who were operated by closed reduction in the last 2 years. We evaluated the postoperative CT scan scores and external deviation criterias 1 month after the operation. Results: The postoperative deviation criteria and postoperative CT scan score were favorable and there were no serious complications using this technique. Conclusion: The present study demonstrates that the use of packing or splinting need not be routine in the majority of cases. The risks and discomforts associated with these procedures can often be avoided.

• 대한두개안면성형외과학회지
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• 제13권2호
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• pp.119-124
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• 2012

Purpose: Closed reduction and nasal packings for 3-7 days is usual procedures in managing nasal bone fracture. Most patients experience several discomfort owing to lack of nasal breathing. There are many reports concerning how to reduce patient's discomforts or complications. But it is obvious that the duration of nasal packing is 3-7 days. The aim of this study is evaluate the effect of half day nasal packing in results of nasal bone fracture. Methods: The study was performed on 97 nasal bone fracture patients who had simple nasal bone fractures from January to June 2012. The incidence, cause, patient's discomfort and satisfaction with half day nasal packing are analyzed according to patient's medical records and questionnaire at each nasal packing removal, postoperative 4 weeks. Results: Young male patients, especially the teenagers and the twenties were the common age group, and physical violence was most common cause of injury. A total of 78 out of 97 patients were male. In 92 cases, closed reduction were applied. Approximately, 87% of the patients were satisfied with the outcomes. Conclusion: Half day nasal packing is considered as an effective method to minimize patient's discomfort owing to prolonged absence of nasal breathing with maintenance of stability.

• Communications for Statistical Applications and Methods
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• 제19권2호
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• pp.225-235
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• 2012

다양한 이유로 인하여 발생하는 영상 잡음은 영상의 화질을 악화시키므로 발생한 잡음을 제거, 감소하는 것이 영상처리 분야에서 매우 중요한 문제이다. 이러한 문제를 해결하는데 가장 근본적인 어려움은 영상 정보에서 제거해야할 잡음과 보존해야 할 신호를 구별하는 것이 쉽지 않다는 것이다. 단순평활법과 같은 잡음 제거과정은 영상을 개선하는데 사용되는 기초적이고 중요한 방법이지만 영상을 오염시키는 잡음의 크기를 고려하지 않는 결점이 있다. 즉, 이러한 방법을 사용하면 잡음을 감소시키는 효과와 함께 잡음이 적거나 없는 부분까지도 열화되어 영상이 흐릿해지는 단점을 보이게 된다. 본 연구에서는 입력 영상에서 신호와 잡음을 효과적으로 구별하여 잡음의 상대적인 크기에 따라 적응적으로 잡음을 제거할 수 있는 방법을 블록 방법을 이용하여 제안한다. 모의실험 결과, 본 연구에서 제안하는 알고리즘에 의해 적응적으로 잡음을 제거함으로써 전체적인 영상의 질이 개선되는 것을 확인하였다.

• 한국해양공학회지
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• 제35권6호
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• pp.393-402
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• 2021

As greenhouse gas emissions from maritime transport are increasing, the International Maritime Organization is continuously working to strengthen emission regulations. Liquefied natural gas (LNG) fuel is less advantageous as a point of CO₂ reduction due to the methane leakage that occurs during the bunkering and operation of marine engines. In this study, greenhouse gas emissions from an LNG-fueled ship were analyzed from the perspective of the life cycle. The amount ofmethane emission during the bunkering and operation procedures with various boil-off gas (BOG) treatment methods and gas engine specifications was analyzed by dynamic simulation. The results were also compared with those of other liquid fuel engines. As a result, small LNG-fueled ships without a BOG treatment facility emitted 32% more greenhouse gas than ships utilizing marine gas oil or heavy fuel oil. To achieve a greenhouse gas reduction via a BOG treatment method, a gas combustion unit or re-liquefaction system must be mounted, which results in a greenhouse gas reduction effect of about 25% and 30%. As a result of comparing the amount of greenhouse gas generated according to the BOG treatment method used with each tank size from the perspective of the operating cycle with the amounts from using existing marine fuels, the BOG treatment method showed superior effects of greenhouse gas reduction.

• 대한방사선기술학회지:방사선기술과학
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• 제39권3호
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• pp.323-328
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• 2016

두경부 질환의 인터벤션 시술 시 시술자가 받는 피폭선량의 평가 및 감소연구를 위한 선행 연구로써, 이온 전리함을 이용하여 인터벤션 시술 시 시술자의 위치하는 공간선량 분포를 측정하였다. Bi-plane 인터벤션 시술 장비를 대상으로 4개 구역(45, 135, 225 그리고 315도)으로 나누어 가상의 시술자가 있다는 가정아래에 시술자의 결정장기위치에서 거리(80, 100, 120, 그리고 140 cm)에 따라 조사선량을 측정하였으며, 방사선발생장치의 위치를 변화시켜 선량변화를 분석하였다. 시술자의 대부분이 위치하는 225도의 구역의 조사선량은 가장 가까운 거리인 80 cm에서 시술자 눈의 높이에서 114.5 mR/h, 가슴의 높이는 143.1 mR/h, 그리고 생식기위치는 147 mR/h이었다. 그리고 방사선 발생장치의 위치를 시술자 가까이로 변화시켰을 경우, 평균적으로 $18.1{\pm}10.5%$의 선량이 증가하였다. 본 연구에서 인터벤션 시술 동안 시술자가 위치할 수 있는 곳의 공간선량분포를 확인하였으며, 본 연구 결과를 통하여 시술자의 방사선 방어에 대하여 구체적인 계획을 수립할 수 있을 것이라 사료된다.

• 대한소아치과학회지
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• 제29권4호
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• pp.519-528
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• 2002

임상에서 설비의 노후나 고장 등으로 인해 고속 핸드피스의 물 분사에 의한 냉각이 종종 불완전하게 일어날 수 있다. 또한 성인에 비해 치료에 관한 공포가 심하여 비협조적인 소아환자의 경우에는 물의 분사나 고속 흡인기의 사용을 거부하거나 지극히 혐오하는 경우도 드물지 않다. 이처럼 냉각이 충분히 이뤄지지 않은 상황에서 시행되는 다양한 술식은 치수조직에 치명적인 손상을 가할 수 있다. 본 연구의 목적은 임상 수복 술식을 시행하는 동안 각 치아표면에서 발생되는 열이 치수 내부로 전달되는 양상을 조사하기 위함이었다. 석고 블록에 식립된 90개의 하악 제2유구치를 대상으로 수종의 수복 술식을 시행하였고, 해당 치아표면에서 발생되는 열의 온도를 적외선 카메라와 thermography를 이용하여 측정하고, 이를 토대로 유한요소 분석을 통한 치질내 열전도에 관한 평가를 시행하였다. 본 연구에서 시행된 임상 술식의 주수 하 최고 표면 온도는 $30.8^{\circ}C{\sim}43.6^{\circ}C$, 비 주수 하에서는 $51.2^{\circ}C{\sim}103.4^{\circ}C$의 범위를 보였다. 술식 중에서는 치관 형성과정이 가장 높은 온도를, 아말감 제거 과정이 가장 낮은 표면온도를 보였다. 동일 술식 내에서의 주수와 비 주수 조건간에는 모든 술식이 유의한 차를 나타냈다(p<0.05). 유한요소 분석에서 나타난 치수각의 온도변화는 모든 비 주수 조건에서는 큰 폭으로 상승한 반면, 주수 하에서는 전반적으로 미약한 변화를 보였다. 이상의 결과는 고속 절삭기를 사용한 수복 과정에 주수에 의한 충분한 냉각이 치수 생활력의 유지를 위해서 필수적임을 시사해준다. 향후 보다 다양한 술식과 조건을 부여한 유사 분야의 연구가 추천된다.