• Journal of Positioning, Navigation, and Timing
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• 제12권3호
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• pp.289-294
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• 2023

As technologies such as cameras, Laser Imaging, Detection, and Ranging (LiDAR), and Global Navigation Satellite Systems (GNSS) become more sophisticated and common, their use in autonomous driving technologies is being explored in various fields. In the maritime area, technologies related to collision avoidance between ships are being developed to evaluate and avoid the risk of collision between ships by setting various scenarios. However, the position of each vessel used in the process of developing collision avoidance technology between vessels uses data obtained through GNSS, and may include a position error of 10 m or more depending on the situation. In this paper, a study on the dynamic safety navigation range including the positional inaccuracy of the ship is conducted. By combining the concept of the protection level obtained using GNSS raw data with a conventional safe navigation range, a safer navigation range can be calculated for dynamic navigation. The calculated range is verified using data obtained while sailing in an actual sea environment.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.245-250
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• 2007

We have proposed Fuzzy-CBR to find a solution from past knowledge retrieved from the database and adapted to a new situation. However, ontology is needed in identifying concepts, relations and instances that are involved in a situation in order to improve and facilitate the efficient retrieval of similar cases from the CBR database. This paper proposes the way to apply ontology fur identifying the concepts involved in a new case, used as inputs, for a ship collision avoidance support system and in solving for similarity through document articulation and abstraction levels. These ontologies will be used to build a conceptual model of a maneuvering situation.

• 한국통신학회논문지
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• 제39C권5호
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• pp.425-432
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• 2014

IEEE 802.11e EDCA(Enhanced Distributed Channel Access)는 서로 다른 AC(Access Category)에 따라서 CW(Contention Window)를 이용하여 Quality-of-Service(QoS)를 지원한다. 그러나 무선 네트워크 환경이 혼잡 (Congested)할 경우 패킷의 충돌 발생 확률을 높일 수 있다는 문제점이 여전히 존재한다. 이를 해결하기 위해 여러 방법들이 제시되었으나 혼잡 네트워크상에서는 동일 우선순위를 가지는 패킷 전송을 위해서 전송 채널을 이용하는 경쟁 과정에서 패킷 충돌(Collision)이 발생할 확률이 여전히 존재한다. 따라서 본 논문에서는 EDCA 포화 상태에서 전송 효율을 높이는 APCA(Advanced Priority Collision Avoidance) 알고리즘을 제안한다. 제안된 알고리즘은 IEEE 802.11e 표준을 기반으로 RTS/CTS (Request to Send / Clear to Send)를 이용하여 패킷 전송 FC(Frame Control) 필드의 예약된 필드(Reserved Field) 비트를 이용하여 데이터 패킷 충돌을 회피하는 것이다. 시뮬레이션의 결과로 제안된 알고리즘이 기존의 EDCA에 비해 패킷 전송 실패율이 감소했음을 보였다. Jain's fairness index를 이용하여 제안된 APCA 알고리즘이 네트워크 혼잡 상황에서 EDCA 방식 보다 공정성을 유지하는 것을 확인하였다.

• 한국지능시스템학회논문지
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• 제16권5호
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• pp.635-641
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning (CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and infer the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
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• pp.39-44
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning(CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and index the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• 한국멀티미디어학회논문지
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• 제15권7호
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• pp.931-940
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• 2012

급속도로 확산되는 소셜 네트워크 서비스는 인터넷이나 모바일을 이용하여 사람들이 상호 관계를 활용하는 시스템이다. SNS는 인간 중심의 네트워크 시스템이다. 본 논문에서는 로봇이 소셜 네트워크 서비스의 일원이 되기 위해서 필요한 구성 요소에 대해서 연구하였다. 통신 기능과 센싱을 가진 로봇이 현재의 상태나 위험 상황 또는 특수 상황들을 공유할 수 있도록 하기 위해서는 로봇의 자율주행, 충돌회피 방법과 통신프로토콜이 필요하다. SNS를 위해 필요한 센서를 조사하고, 로봇의 충돌회피 방법을 연구하고 SNS를 위한 로봇의 프로토콜을 정의한 후 이를 구현하였다. 그리고 유무선 통합 통신 방식을 제안하고 구현하였다.

• 한국항해학회지
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• 제17권1호
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• pp.1-15
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• 1993

According to careful study on the COLREGS, 1972, we can easily find out a main point that is to eliminate risk of collision at sea through exercising due regard to all danger of navigation and collision and to any special circumstances including the limitation of the vessels involved, or precaution which may be required by the ordinary practice of seamen. This paper, therefore, aims to clarify legal concept concerning the risk of collision so as to easier assimilate and understand by all mariner before being presented with a situation of danger in realty. After such a forethought and understanding the mariner will be in a position timely to implement the due regard or precaution to avoid collision by himself. For the purpose of good guidance, comprehensive legal practices of collision avoidance are adequately summarized by foreign and domestic cases.

• 한국항공운항학회지
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• 제18권3호
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• pp.27-33
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• 2010

The goal for the CD&R system is to predict that a conflict is going to occur in the future, communicate the detected conflict to a human operator, and, in some cases, assist in the resolution of the conflict situation. To provide insight into different methods of conflict detection and resolution, a literature review of previous research models and current developmental and operational systems was performed. This paper focuses only on the specific attributes of each model, not on the depth to which a model has been analyzed, validated, or accepted. Thus, care should be taken to remember that a model that seems to be simple according to our categorization scheme may be significantly more viable than an apparently sophisticated model.

• 한국산학기술학회논문지
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• 제9권2호
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• pp.388-394
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• 2008

본 논문에서는 IEEE 802.11 WLAN(Wireless LAN)의 MAC(Medium Access Control)인 DCF(Distributed Coordination Function)의 성능을 개선하는 알고리즘을 제안하고 이를 시뮬레이션으로 분석한다. IEEE 802.11 WLAN의 MAC에서는 데이터 전송을 제어하기 위한 방법으로 DCF와 PCF(Point Coordination Function)를 사용하며, DCF의 경우 CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance)를 기반으로 한다. DCF는 경쟁 스테이션이 적은 상황에서는 비교적 우수한 성능을 보이나 경쟁 스테이션의 수가 많은 경우 처리율, 지연 관점에서 성능이 저하되는 문제점이 있다. 본 논문에서는 패킷 전송 후 충돌이 발생하면 윈도우 값을 최대 CW로 증가시키고 패킷의 정상적인 전송 후에는 윈도우 값을 서서히 감소함으로써 현재 WLAN의 망 상태정보를 계속 활용함으로써 패킷 충돌 확률을 낮추는 알고리즘을 제안한다. 제안하는 알고리즘의 효율성을 입증하기 위해 시뮬레이션을 수행하여 그 타당성을 제시하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.327-330
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• 1995

If a mobile robot is used in a real situation, robot must face a moving obstacles. In that case, the collision avoidance algorithm for moving obstacle is a indispensible element in mobile robot control. We csrried out a research to find and evaluate the advanced algorithm for mobile robot. At first we generate the continous path for mobi;e robot. Then by creating a curved path for avoidance, the mobile robot can change its path smoothly. Smoothed path made the robot adapt more effectively to the changing of path. Under time-varying condition, computer simulation was performed to show the validation of proposed algorithm.