• 대한기계학회논문집A
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• 제34권1호
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• pp.1-9
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• 2010

본 연구의 목적은 저속충돌에서 승용차량의 범퍼체결구조를 분석하기 위한 것이다. 차량의 손상성-수리성 향상 연구를 위해 범퍼체결구조가 서로 상이한 3개 차종에 대해 RCAR(세계자동차 수리기술위원회)의 저속충돌시험(전,후면 40% 오프셋 충돌시험) 기준을 적용하였다. 시험결과 충격흡수능력은 직사각형 단면형상을 가지고 그 부분이 범퍼레일에 삽입되는 크래시박스식의 범퍼스테이가 대부분의 차량에 적용되고 있는 다른 두 유형의 범퍼체결구조에 비해 우수하게 나타났다. 우수하게 설계된 직사각형 단면형상을 가지는 범퍼체결구조가 저속충돌사고 시 차량의 손상성-수리성을 향상시킴으로써 승객의 안전성도 강화시킬뿐만 아니라 수리비 절감에도 기여할 수 있다는 것이 본 연구에서 입증되었다.

• 대한교통학회지
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• 제32권4호
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• pp.369-379
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• 2014

전통적인 사고예측모형은 통계적 회귀분석에 주로 의존하였으나, 이는 자료 분포 및 함수 형태에 대한 가정에 따른 한계를 가지고 있다. 이에 따라 일부 연구는 신경망 등의 비모수적 기법을 모형 구축에 활용하였으나, 이는 독립변수와 종속변수 간의 직접적인 관계 규명이 어렵다는 한계가 있다. 유전자 프로그래밍 기법은 모형 개발에 특별한 가정이 필요없고, 사고요인 규명이 가능하다는 장점이 있다. 따라서 본 연구에서는 고속도로의 사고예측에 유전자 프로그래밍 기법을 적용함으로써 이러한 한계를 극복하고자 하였다. 이를 위하여 경부고속도로에서 최근 3년간(2010-2012년) 구득된 자료를 활용하였으며, 보다 세밀한 사고 특성 규명을 위해 고속도로 구간을 직선 구간과 곡선 구간으로 구분하였다. 사고 발생에 중요한 영향을 미치는 변수를 선택하기 위하여 랜덤 포레스트 기법을 이용하였으며, 최종 선택된 변수들을 활용하여 사고예측을 위한 유전자 프로그래밍 모형을 구축하였다. 구축된 모형의 예측 성능을 평가하기 위해 음이항 회귀모형과 비교해본 결과, 유전자 프로그래밍 모형의 예측 성능이 더 우수한 것으로 나타났다.

• 한국도로학회논문집
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• 제15권5호
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• pp.203-215
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• 2013

PURPOSES : This study deals with first traffic violations occurred by novice drivers, which may be associated with traffic accidents. The objective of this study is to identify what kinds of drivers' characteristics influence on duration till the first traffic violation. METHODS : For the study, Survival Analysis and Cox proportional hazard model, that are usually used in the medical field, were employed. Survival Analysis was conducted to investigate whether there exist differences in survival duration by each covariate, whereas Cox proportional hazard model was used to identify significant factors that affect survival duration till novice drivers violate traffic regulations for the first time after getting a driver license. RESULTS : The results of Survival Analysis indicate that female, age (less than 21), low-frequency examinee of written exam, and non-crash involved drivers have longer duration till the first violation compared to male, greater than 21 years old, high-frequency examinee of written exam, and crash involved drivers, respectively. For the Cox proportional hazard model, license class 1 acquisitor was found to increase the survival duration till the first traffic violation was made, while male, age of 21-24, age of 25-34, age of 45-54, and crash involved drivers were more likely to reduce the survival duration. CONCLUSIONS : Absolutely, traffic violation is closely related to traffic accidents and all of the drivers should keep the traffic regulations to enhance highway safety. The results of this study might provide some insights to construct safe road environments by controlling the factors that reduce the traffic violation duration of novice drivers.

• Wind and Structures
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• 제20권5호
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• pp.643-660
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• 2015

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.437-439
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• 2006

Actually, The present traffic accident detection system is subsisting limitation of accurate distinction under the crowded condition at intersection because the system defend upon mainly the image information at intersection and digital image processing techniques nearly all. To complement this insufficiency, this article aims to estimate the level of present technology and a realistic possibility by analyzing the acoustic characteristic of crash sound that we have to investigate for improvement of traffic accident detection rate at intersection. The skid sound of traffic accident is showed the special pattern at 1[kHz])${\sim}$3[kHz] bandwidth when vehicles are almost never operated in and around intersection. Also, the frequency bandwidth of vehicle crash sound is showed sound pressure difference oyer 30[dB] higher than when there is no occurrence of traffic accident below 500[Hz].

• Journal of Chest Surgery
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• 제27권12호
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• pp.1023-1026
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• 1994

We reviewed 10 cases of traumatic diaphragmatic injuries at Soonchunhyang University Gumi Hospital from January 1990 through April 1993. seven patients were male and three patients were female. The age distribution was ranged from 25 to 79 years, predominant 4th decades occurred in male. The traumatic diaphragmatic injuries were due to blunt trauma in 9 cases (traffic accident 7 and crash injury 2) and penetrating wound in 1 case (stab wound). The common symptom were dyspnea (60%), chest pain and abdominal pain in order frequency. In the blunt trauma and crash injury, te rupture site was all located in the left(9 cases). In the penetrating wound, the rupture site was located in the right(1 case). The surgical repair of 10 cases were performed with transthoracic approach in 9 cases and thoracoabodominal approach in 1 case. The postoperative mortality was 10% (1/10). The cause of death was multiple organ failure with pulmonary edema.

• Journal of Chest Surgery
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• 제27권12호
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• pp.1027-1030
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• 1994

We reviewed 10 cases of traumatic diaphragmatic injuries at Soonchunhyang University Gumi Hospital from January 1990 through April 1993. Seven patients were male and three patients were female. The age distribution was ranged from 25 to 79 years, predominant 4th decades occurred in male. The traumatic diaphragmatic injuries were due to blunt trauma in 9 cases[traffic accident 7 and crash injury 2] and penetrating wound in 1 case[stab wound]. The common symptoms were dyspnea[60%], chest pain and abdominal pain in order frequency. In the blunt trauma and crash injury, the rupture site was all located in the left[ 9 cases ]. In the penetrating wound, the rupture site was located in the right[1 case]. The surgical repair of 10 cases were performed with transthoracic approach in 9 cases and thoracoabdominal approach in 1 case. The postoperative mortality was 10%[1/10]. The cause of death was multiple organ failure with pulmonary edema.

• 한국ITS학회 논문지
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• 제23권1호
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• pp.134-145
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• 2024

본 연구의 목적은 조건부 운전면허 발급에 필요한 평가 시나리오 개발 프레임워크를 제안하는 것이다. 이를 위해 프레임워크는 5단계로 구성하였다. 1단계에서는 고령 운전자에 의한 충돌사고의 주요 요인을 사고빈도와 심각도 측면에서 교통사고 특성에 대한 문헌을 검토하였다. 2단계는 도로교통공단 교통사고분석시스템 사고 자료를 활용하여 비고령, 초기 고령, 후기 고령 집단별 교통사고 특성에 대한 분석을 수행하였다. 이를 통해 고령 운전자 등 고위험군 교통사고 유형을 도출하였다. 3단계는 고위험군 교통사고 유형에 해당하는 블랙박스 영상을 분석하여 사고가 발생한 상황에 대해 기술한 교통사고 스토리를 도출하였다. 4단계는 다양한 시나리오 개발을 위해 도출된 사고 스토리의 유형을 분류하여 여러 가지 사고 상황을 구분하였다. 5단계는 최근 다양한 자율주행차량 평가 시나리오 개발에 활용되고 있는 PEGASUS 5-Layer 형식을 적용하여 시나리오를 제시하였다. 본 연구의 결과는 향후 조건부 운전면허 발급을 위한 운전능력 평가시나리오 개발의 기반으로 활용될 것으로 기대된다.

• 한국정보통신학회논문지
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• 제9권2호
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• pp.237-241
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• 2005

기존의 블루투스 버전 1.0에서의 주파수 호핑방식은 하나의 피코넷에서 특정한 주파수를 사용하여, 디바이스의 클럭과 주소의 특정한 영역의 정보를 참조하여 결정되는 알고리즘을 가지고 있었다. 기본적인 호핑 패턴은 ISM 밴드의 79개의 주파수를 pseudo-random 방식으로 나열하는 것이었다. 이때 발생하는 문제점은 주위에 같은 호핑 주파수를 사용하는 다른 무선 디바이스가 있는 경우 하나의 주주파수 호핑(adaptive frequency hopping) 방식은 이러한 문제점을 해결하여 두 가지 이상의 무선 디바이스가 공존하여 채널을 사용할 수 있도록 한다. 제안된 방식은 HDL로 구현되어 자동합성되었으며, 자동 레이아웃 되어 검증되었다. 제안된 방식은 구현의 주체가 될 블루투스 디바이스 주파수인 24MHz에서 정상적으로 동작하였다.

• Journal of Preventive Medicine and Public Health
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• 제50권3호
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• pp.158-164
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• 2017

Objectives: To identify bacterial contamination rates of laryngoscope blades and handles stored in emergency crash carts by hospital and area according to the frequency of intubation attempts. Methods: One hundred forty-eight handles and 71 blades deemed ready for patient use from two tertiary hospitals were sampled with sterile swabs using a standardized rolling technique. Samples were considered negative (not contaminated) if no colonies were present on the blood agar plate after an 18-hour incubation period. Samples were stratified by hospital and according to the frequency of intubation attempts (10 attempts per year) using the ${\chi}^2-test$ and Fisher exact test. Results: One or more species of bacteria were isolated from 4 (5.6%) handle tops, 20 (28.2%) handles with knurled surfaces, and 27 (18.2%) blades. No significant differences were found in microbial contamination levels on the handle tops and blades between the two hospitals and two areas according to the frequency of intubation attempts. However, significant differences were found between the two hospitals and two areas in the level of microbial contamination on the handles with knurled surfaces (p<0.05). Conclusions: Protocols and policies must be reviewed to standardize procedures to clean and disinfect laryngoscope blades and handles; handles should be re-designed to eliminate points of contact with the blade; and single-use, one-piece laryngoscopes should be introduced.