• Composites Research
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• v.36 no.1
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• pp.59-67
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• 2023

Damage caused by impact on a vehicle composed of CFRP(carbon fiber reinforced plastic) composite to reduce weight in the aerospace industries is related to the safety of passengers. Therefore, it is important to understand the damage behavior of materials that is invisible in impact situations, and research through the FEM(finite element model) is needed to simulate this. In this study, FEM suitable for predicting damage behavior was constructed for impact analysis of unidirectional laminated composite. The calibration parameters of the MAT_54 Enhanced Composite Damage material model in LS-DYNA were acquired by inverse estimation through ANN(artificial neural network) model. The reliability was verified by comparing the result of experiment with the results of the ANN model for the obtained parameter. It was confirmed that accuracy of FEM can be improved through optimization of calibration parameters.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.223-233
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• 2023

Gauss Sieve is an algorithm for solving SVP and requires exponential time and space complexity. The terminationcondition of the Sieve is determined by the size of the constructed list and the number of collisions related to space complexity. The term 'collision' refers to the state in which the sampled vector is reduced to the vector that is already inthe list. if collisions occur more than a certain number of times, the algorithm terminates. When executing previous algorithms, we noticed that unnecessary operations continued even after the shortest vector was found. This means that the existing termination condition is set larger than necessary. In this paper, after identifying the point where unnecessary operations are repeated, optimization is performed on the number of operations required. The tests are conducted by adjusting the threshold of the collision that becomes the termination condition and the distribution in whichthe sample vector is generated. According to the experiments, the operation that occupies the largest proportion decreased by62.6%. The space and time complexity also decreased by 4.3 and 1.6%, respectively.

• The Journal of Bigdata
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• v.7 no.1
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• pp.89-97
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• 2022

Various efforts are needed to prevent accidents because ship collisions can cause various negative situations such as economic losses and casualties. Therefore, research to prevent accidents is being actively conducted, and in this study, new leading indicators for preventing ship collision accidents is proposed. In previous studies, the risk of collision was expressed in consideration of the distance between ships in a specific sea area, but there is a disadvantage that a new model needs to be developed to apply this to other sea areas. In this study, the density-based ship domain DESD (Density-based Empirical Ship Domain) including the environment and operating characteristics of the sea area was defined using AIS (Automatic Identification System) data, which is ship operation information. Deep clustering is applied to two-dimensional DESDs created for each sea area to cluster the seas with similar operating environments. Through the analysis of the relationship between clustered sea areas and ship collision accidents, it was statistically tested that the occurrence of accidents varies by characteristic of each sea area, and it was proved that DESD can be used as a leading indicator of accidents.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.61-74
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• 2005

This study is to investigate the effects of driving anger and traffic congestion on drivers' behaviors. Driving anger is the propensity to become angry while driving, and people differ in the tendency to get angry when encountering frustration and provocation on the road. Individual differences of the propensity contribute to anger on the road and aggressive driving leading traffic vaiolations and accidents. In the experiment three traffic conditions (an open road condition, a bumper-to-bumper traffic condition and a being stuck behind a slower driver condition) were simulated and driving behaviors were collected with RTSA-DS(Road Traffic Safety Authority-Driving Simulator). The results were as follows: Most of high anger drives drove at higher speeds in an open road condition, and in the bumper-to-bumper condition they drove faster and had an higher crash rate, which suggests they did aggressive driving, and risky and unsafe behaviors.

• Journal of Navigation and Port Research
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• v.37 no.4
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• pp.401-407
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• 2013

In parallel with the development of ship equipment, bridge systems have been improved, but marine accidents due to human error have not been reduced. Recently, research in nautical bridge equipment has focused on suitable ergonomic designs in order to reduce these errors due to human factors. In a bridge of a ship, there are numerous auditory signals that deliver important information clearly to the sailors. However, only a few studies have been conducted related to the human recognition of these auditory signals. There are three types of auditory signals: voice alarms, abstract sounds, and auditory icons. This study was conducted in order to design more appropriate auditory icons using a sensibility evaluation method. The auditory icons were rated to have five warning situations (engine failure, fire, steering failure, low power, and collision) using the Semantic Differential Method. It is expected that the results of this study will be used as basic data for auditory displays inside bridges and for integrated bridge alarm systems.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.337-339
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• 2005

무선 링크를 사용하는 모바일 기기는 모바일 기기의 이동 혹은 무선 링크의 충돌, 부족한 대역폭등 모바일 기기의 외적 환경 변화에 의해 잦은 단절과 실패를 겪게 된다. 이러한 환경 변화를 예측할 수 있다면, 모바일 기기 내의 어플리케이션이 상황에 따른 적절한 대응을 할 수 있다. 본 논문에서는 어플리케이션이 링크의 환경 변화에 적응할 수 있도록, 링크의 상태 정보를 이용하여 상태를 예측할 수 있는 가중치 알고리즘과 상태 변화의 정도를 추정할 수 있는 기울기 값을 이용한 Watermark 기반의 링크 상태 추적 알고리즘을 제안한다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.556-561
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• 2003

선박에 의한 해난사고의 대부분을 차지하고 있는 충돌과 좌초를 예방하고 안전항행환경을 확보하기 위해서는 선박들의 교통량 정보 및 위치정보, 해상환경정보를 얻지 않으면 안 된다. 본 연구에서는 인공위성데이터를 통해 얻어진 선박정보를 추출하는 방법에 대해서 조사하고, 다시 얻어진 선박정보를 이용해서 장래위치에 있어서의 해상교통환경 시뮬레이션을 했다. 즉, 장래 해상교통상황을 정량화 된 값으로 표현하여 자동차용 교통신호와 비슷한 선박들의 교통제어신호를 제공함으로써 해상교통안전을 확보할 수 있는 시스템의 기초적 연구결과를 제시했다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.71-72
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• 2001

최근 연근해 어선에서는 소형 레이더 장치를 항해 및 어로장치와 함께 탑재하고 있으나, 소형 레이더에 있어서는 타선의 진운동정보(진침로, 진속력)나 충돌회피정보(CPA, TCPA), 또한, 주위의 상황변화에 대한 다양한 물표정보(진운동벡터표시, 실시간 추적정보)를 제공할 수 없는 문제가 있다. (중략)

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.116-118
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• 2018

본 연구의 목적은 선박조종시뮬레이터(Ship Handling Simulator)를 이용하여 해기사 SRK(Skill-, Rule-, Knowledge) 기반 행동 측정을 하고자 하는 것이다. SRK 행동은 Rasmussen에 의해 제안된 행동 이론이며, 인적오류로 인한 사고는 매년 발생하고 있고, 인적오류로 인한 해양사고를 줄이고자 하는 연구가 필요하다. 우선 해기사 SRK 행동을 정의하고, 선박조종시뮬레이터를 이용하고 다양한 시나리오를 통해 해양사고 중 충돌상황에 대하여 측정 방법을 연구하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.48-49
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• 2020

자율운항선박의 운항과 관련된 각종 센서들에 대한 정확한 분류 및 평가는 항해·충돌방지 자율운항 선박 개발에 있어서 중요한 역할을 한다. 이 연구에서는 원격 모니터링 설계를 위한 모니터링 대상의 개념, 구성 및 연관 기능에 대하여 분석하고 시나리오 기반의 평가방법에 대하여 연구 하였다.