• 한국안전학회지
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• 제11권4호
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• pp.3-9
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• 1996

In this study, comparison of theoretical solutions with experimental results is examined through fracture conditions for the case of float glasses subjected static loading. The range of fracture generation limits and critical penetration energies are solved according to the impactor mass under the high velocity, and analytical method of fracture strength and penetration strength are presented. Also, fracture patterns are investigated according to impact velocities. The results obtained from this study are as follows ; 1) Radial cracks are generated from the loading point regardless of plate thickness in the case of the plate subjected to the static loading. In the case of high-speed impact, dimensions of ring cracks become to smaller and length of radial cracks becomes shorter with the rapidity of impact velocity. 2) Kinetic change volume of collision after/before is constant regardless of velocities over the range of critical penetration velocity. 3) Although the same impact energy is working, the critical penetration energy is increased with the shorter of impactor mass. 4) Although the same impact energy is working, the penetration fracture of lighter Impactor mass is generated more than that of heavier impactor mass, and the impulse of lighter impacter mass appear more than that of heavier impactor mass. Therefore, the penetration fracture in the case of greater impulse is generated earlier regardless of the of the dimensions of Impact loading.

• 해양환경안전학회지
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• 제3권1호
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• pp.1-14
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• 1997

This paper describes a series of numerical simulations of colision between a 310, 000 DWT double hull VLCC (struck ship) and three 35, 000, 70, 000 and 105, 000 DWT tankers (striking ships) using LS/DYNA3D. Collisions are assumed to occur at the middle of the VLCC with the striking ships moving at right angle to the VLCC centerline. Striking ship speeds are varied to find a critical speed without failure of inner side shell, and the informations of collision force and absorption energy of each case are also reported. The validation of LS/DYNA3D in this study was made by comparing the result of numerical simulation of LS/DYNA3D with that of double hull tanker grounding experiment by the Carderock Division of Navla Surface Warfare Center (CDNSWC).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.101-104
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• 2000

Nowadays, the issue of congestion control in high-speed communication networks becomes critical in view of the bandwidth-delay products for efficient data flow. In particular, the fact that the congestion is often accompanied by the data flow from the high-speed link to low-speed link is important with respect to the stability of closed-loop congestion control. The Virtual-Connection Network (VCN) in Gigabit Ethernet networks is a packet-switching based network capable of implementing cell- based connection, link-by-link flow-controlled connection, and single- or multi-destination virtual connections. VCN described herein differ from the virtual channel in ATM literature in that VCN have link-by-link flow control and can be of multi-destination. VCNs support both connection-oriented and connectionless data link layer traffic. Therefore, the worst collision scenario in Ethernet CSMA/CD with virtual collision brings about end-to-end delay. Gigabit Ethernet networks based on CSMA/CD results in non-deterministic behavior because its media access rules are based on random probability. Hence, it is difficult to obtain any sound mathematical formulation for congestion control without employing random processes or fluid-flow models. In this paper, an analytical method for the design of a congestion control scheme is proposed based on Smith＇s principle to overcome instability accompanied with the increase of end-to-end delays as well as to avoid cell losses. To this end, mathematical analysis is provided such that the proposed control scheme guarantees the performance improvement with respect to bandwidth and latency for selected network links with different propagation delays. In addition, guaranteed bandwidth is to be implemented by allowing individual stations to burst several frames at a time without intervening round-trip idle time.

• Journal of Trauma and Injury
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• 제33권2호
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• pp.128-133
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• 2020

Traumatic abdominal wall hernias (TAWHs) are uncommon and the incidence of this, which is rarely encountered in clinical practice, has been estimated at 1%. Furthermore, blunt transection of the entire abdominal wall musculature caused by seatbelt is a very rare complication. We report a case of adult with a complete disruption of the entire anterolateral abdominal wall muscle following the seatbelt injury. A 32-year-old male was wearing a seat belt in a high speed motor vehicle collision. Abdominal computed tomography (CT) scan revealed the complete disruption of bilateral abdominal wall musculatures including TAWH without visceral injury. However, injuries of small bowel and sigmoid colon were observed in the intra-operative field. The patient underwent the repair by primary closure of the defect with absorbable monofilament sutures. This case suggests that especially in TAWH patients, even if a CT scan is normal, clinicians should keep the possibility of bowel injury in mind, and choose a treatment based on the clinical findings.

• 대한전자공학회논문지TC
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• 제43권5호
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• pp.137-146
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• 2006

IP 주소 검색 구조는 라우터 시스템에서 고속 네트워크 기술의 중요한 이슈가 되고 있으며 패킷 전달의 성능을 좌우하는 주요한 문제 요소로 지적되고 있다. 본 논문에서는 복수 해슁의 적응적인 적용과 프리픽스 그룹화를 이용하여 효율적인 고속 IP 주소 검색 구조를 제안한다. 여러 라우팅 데이터의 엔트리 분포를 분석하여 프리픽스를 그룹화하고 그룹별로 적용되는 해쉬함수의 개수를 적응적으로 적용하여 해슁에 의한 충돌(collision)을 줄일 수 있었으며 이를 통해 테이블의 수를 최적화하고 메모리 효율을 높일 수 있었다. 또한 제안하는 구조는 단 한 번의 메모리 접근만으로 포워딩 테이블의 구성 및 검색 과정을 수행할 수 있는 고속 구조이다.

• 한국시뮬레이션학회논문지
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• 제29권3호
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• pp.1-8
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• 2020

적 무인기가 거대 도시지역에 침투 시 다양한 형태의 대공화기들이 넓은 지역에 배치되어 대응한다. 대공무기의 특징상 다량으로 비행체에 대해서 사격함으로 명중탄을 제외한 잔여탄은 자체 폭발 후 다양한 크기의 파편으로 낙하한다. 파편이 지상으로 낙하하면서 인명에게 피해를 줄 수 있는 임계속도, 파편질량, 파편 초기속도, 물체충돌 속도 등 4가지 요소를 도출하여 대공포와 유도무기로 구분하여 피해율을 분석하였다. 앞으로 북은 비대칭전력인 무인기를 활동하여 수도서울에 대한 침투가 예상됨으로 대응 간 인명 피해 최소화를 위해 사전 피탄지역과 사격제한지역을 설정해 둠으로서 피해를 최소화 할 수 있을 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권2호
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• pp.692-712
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• 2022

Buoys used for Aid to Navigation systems are widely used to guide the sea paths and are powered by batteries, requiring continuous battery replacement. However, since human labor is required to replace the batteries, humans can be exposed to dangerous situation, including even collision with shipping vessels. In addition, Maritime sensors are installed on the route signs, so that these are often damaged by collisions with small and medium-sized ships, resulting in significant financial loss. In order to prevent these accidents, maritime object detection technology is essential to alert ships approaching buoys. Existing studies apply a number of filters to eliminate noise and to detect objects within the sea image. For this process, most studies directly access the pixels and process the images. However, this approach typically takes a long time to process because of its complexity and the requirements of significant amounts of computational power. In an emergent situation, it is important to alarm the vessel's rapid approach to buoys in real time to avoid collisions between vessels and route signs, therefore minimizing computation and speeding up processes are critical operations. Therefore, we propose Fast Connected Component Labeling (FCCL) which can reduce computation to minimize the processing time of filter applications, while maintaining the detection performance of existing methods. The results show that the detection performance of the FCCL is close to 30 FPS - approximately 2-5 times faster, when compared to the existing methods - while the average throughput is the same as existing methods.

• 수산해양기술연구
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• 제45권3호
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• pp.165-176
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• 2009

The process of berthing/deberthing operations for entering/leaving vessels in Busan northern harbor was analyzed and evaluated by using an integrated VTS(vessel traffic service) system installed in the ship training center of Pukyong National University, Busan, Korea. The integrated VTS system used in this study was consisted of ARPA radar, ECDIS(electronic chart display and information system), backup(recording) system, CCTV(closed-circuit television) camera system, gyro-compass, differential GPS receiver, anemometer, AIS(automatic identification system), VHF(very high frequency) communication system, etc. The network of these systems was designed to communicate with each other automatically and to exchange the critical information about the course, speed, position and intended routes of other traffic vessels in the navigational channel and Busan northern harbor. To evaluate quantitatively the overall dynamic situation such as maneuvering motions for target vessel and its tugboats while in transit to and from the berth structure inside a harbor, all traffic information in Busan northern harbor was automatically acquired, displayed, evaluated and recorded. The results obtained in this study suggest that the real-time tracking information of traffic vessels acquired by using an integrated VTS system can be used as a useful reference data in evaluating and analyzing exactly the dynamic situation such as the collision between ship and berth structure, in the process of berthing/deberthing operations for entering/leaving vessels in the confined waters and harbor.

• 한국통신학회논문지
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• 제31권5B호
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• pp.378-389
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• 2006

IP 주소 검색 구조는 IPv6 주소체계의 도래와 함께 더욱 고속 네트워크 기술의 중요한 이슈가 되고 있다. 본 논문에서는 차세대 인터넷 라우터를 위한 새로운 글로벌 IPv6 유니캐스트 주소 검색 구조를 제안한다. 제안하는 구조는 적절한 프리픽스 그룹화를 수행하고 각 그룹별로 가변적으로 복수 해슁을 수행한다. 이를 통해 적절한 개수의 포워딩 테이블에서 해슁의 충돌(collision)을 효율적으로 분산함으로서 오버플로우를 최소화하였으며 포워딩 테이블 구성을 위해 필요한 메모리 크기를 줄였다. 또한 단 한 번의 메모리 접근만으로 포워딩 테이블 구성 및 검색이 가능한 고속 주소 검색 구조이며 추가적 업데이트가 용이한 구조이다. 실제 6bone 테스트 라우팅 CERNET 데이터를 이용하여 균일한 복수 해슁을 이용한 구조와 제안한 구조를 비교, 실험하였으며 동일한 8개의 테이블에서 약 15%의 포워딩 테이블을 위한 메모리 절약과 약 50%의 오버플로우 감소를 확인하였다.

• 대한토목학회논문집
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• 제39권3호
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• pp.391-398
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• 2019

일반적으로 화물차 사고는 일반 승용차 사고 대비 심각도가 높은 것으로 알려져 있으며, 최근 국내 화물차 사고 발생건수 및 사망률은 지속적으로 증가하고 있는 추세이다. 그러나 국내 화물차 사고 심각도 관련 연구는 매우 제한적으로 수행되었다. 이러한 배경 하에 본 연구는 국내 고속도로에서 과거 6년간 발생한 화물차 사고 심각도를 분석하여 화물차 사고 심각도에 영향을 미치는 인자를 도출하고자 한다. 분석을 위해 순서형 프로빗 모형이 적용되었으며 총 10개의 주요 인자가 도출되었다. 이중 8개 인자(나이가 많을수록, 졸음운전의 경우, 추돌 사고의 경우, 사고 후 전도나 전복이 된 경우, 사고 후 화재가 발생한 경우, 사고에 포함된 차량 수가 많을수록, 충돌 속도가 높을수록, 야간주행(0-6시)에 발생한 사고의 경우)는 사고 심각도가 높아지는 것으로, 2개 인자(눈이 오는 경우, 단독차량사고의 경우)는 감소시키는 것으로 나타났다. 본 연구 결과는 국내 고속도로 화물차 사고 심각도를 낮추기 위한 정책 수립 시 기반 자료로 활용할 수 있을 것으로 기대된다.