• 한국통신학회논문지
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• 제36권3B호
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• pp.248-253
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• 2011

선박의 충돌회피 알고리즘은 인적 요인에 의한 해난사고를 방지하고, 보다 효과적이고 안전한 운항을 위해 개발되어 왔다. 본 논문에서는 충돌사고의 위험성을 줄이고, 안전운항을 지원하기 위하여, 베이지안 추정 이론을 이용하여 충돌 위험도를 추정하는 알고리즘을 고안한다. 기존의 선박 충돌 회피를 시스템보다 안전한 충돌 회피를 위해서 베이지안 추정 이론을 이용하여 충돌 위험도를 계산하고 일정 시간 이후에 타선들의 위치 및 속도정보와 자선의 위치 및 속도정보를 이용하여 충돌 위험도를 예측함으로써 보다 안전하고 효율적인 충돌 위험도를 결정한다. 본 논문에서 타선박의 항해정보는 AIS 정보를 가정하였고, 기존의 DCPA와 TCPA를 이용한 퍼지 추론 방법보다 효율적으로 충돌 위험도를 추정할 수 있다.

• 한국정보통신학회논문지
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• 제19권4호
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• pp.807-812
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• 2015

RFID 시스템에서 리더의 식별영역 내에 있는 태그들이 동시에 응답하면 충돌이 발생한다. 이러한 충돌을 해결하기 위한 방법이 충돌 방지 알고리즘이다. Auto-ID 센터에서는 13.56MHz RFID 시스템에서 다중 태그를 식별하기 위한 충돌 방지 알고리즘으로 STAC 프로토콜을 제안하였다. PS 알고리즘은 리더의 송신 전력을 점진적으로 증가시키면서 리더의 식별 영역 내에 있는 태그들을 그룹화 하여 식별하는 기법이다. 본 논문에서는 STAC 프로토콜에 PS 알고리즘을 적용한 STAC/PS 알고리즘을 제안하고, 이에 대한 성능을 분석한다. 시뮬레이션을 통한 성능분석의 결과, 제안한 기법은 충돌률이 STAC 프로토콜에 비하여 50% 정도 낮으므로 태그 식별 시간이 짧음을 알 수 있었다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1996년도 추계학술대회 학술발표 논문집
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• pp.279-282
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• 1996

Collision avoidance is a method to direct a mobile robot without collision when traversing the environment. This kind of navigation is to reach a destination without getting lost. In this paper, we use a genetic algorithm for the path planning and collision avoidance. Genetic algorithm searches for path in the entire, continuous free space and unifies global path planning and local path planning. It is a efficient and effective method when compared with traditional collision avoidance algorithm.

• 대한조선학회논문집
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• 제56권1호
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• pp.75-81
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• 2019

This study presents an automatic collision avoidance algorithm for autonomous navigation of unmanned surface vessels. The performance of the collision avoidance algorithm is heavily dependent on the estimation quality of the course and speed of traffic ships because collision avoidance maneuvers should be determined based on the predicted motions of the traffic ships and their trajectory uncertainties. In this study, the collision avoidance algorithm is implemented based on the Probabilistic Velocity Obstacle (PVO) approach considering the maritime collision regulations (COLREGs). In order to demonstrate the performance of the proposed algorithm, an extensive set of simulations was conducted and the results are discussed.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.233-247
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• 1999

Traffic accidents are normally caused by late or faulty judgements due to the driver's inaccurate estimation of the distance, velocity, and acceleration from the surrounding vehicles as well as his carelessness or inattention. Thus, the development of collision avoidance systems is motivated by their great potential for increased vehicle safety. A typical collision avoidance system consists of the forward-looking sensor, the criteria for activation of collision warming and avoidance, the collision avoidance maneuvers, and the user interface. This thesis is concerned with the development of a collision warning algorithm in which the driver is warned of approaching collision with the visual and/or the audible signals . The warning algorithm based on fuzzy logic is presented here based on new warning criteria. It has been newly derived from the conventional warning equation by adding a new input variable of the required deceleration to avoid collision. The algorithm is also able to adapt to the individual driver's taste along with the different road conditions by externally controlling the warning intensity. Finally , the proposed algorithm has been validated using computer simulation.

• Journal of information and communication convergence engineering
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• 제6권1호
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• pp.24-28
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• 2008

In RFID System, when multiple tags respond simultaneously, a collision can occur. A method that solves this collision is referred to anti-collision algorithm. Among the existing anti-collision algorithms, static framed slot allocation algorithm is very simple. But when the number of tags is variable, its performance degrades because of the fixed frame size. This paper proposes an optimal frame size allocation scheme that determines the frame size. The proposed scheme is based on the number of collision slots at every frame. According to the simulation results, the tag identification time is faster that of SFSA.

• 한국정밀공학회지
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• 제14권1호
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• pp.158-167
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• 1997

For the use of a mobile robot in dynamic environment, a collision-avoidance algorithm with moving obsta- cle is necessary. In this paper, a collsion-avoidance algorithm of a mobile robot is presented, when a mobile robot detects the collision with moving obstacle on the navigational path. Using reported positions of moving obstacle with sensors, the mobile robot predicts the next position of moving obstacle with possibility of collision. The velocity of moving obstacle is modeled as random walk process with Gaussian distribution. The optimal collision-avoidance path in which turning motion of the mobile robot is considered is generated with relative velocity between the mobile robot and moving obstacle. For the safety of collision-avoidance path, attractive potential with the safety factor is suggested. The simulation results using this algorithm show the mobile robot avoids collision with moving obstacle in many cases.

• 한국통신학회논문지
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• 제31권4A호
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• pp.431-439
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• 2006

RFID 다중 태그 인식이란 하나의 RFID 리더 영역 내에 있는 다수의 태그를 태그 간의 통신 간섭에 의한 충돌을 피하며 고속으로 인식하는 기술이다. 다중 태그 인식 기술은 RFID 시스템의 성능과 안정성을 결정하는 핵심 기술로 중요성이 높다. 논문은 대표적 다중 태그 인식 기술인 QT(Query Tree) 알고리즘의 충돌 비트 위치를 활용하여 개선된 QT-CBP(Query Tree with Collision-Bit Positioning) 알고리즘을 제안한다. 시뮬레이션을 통한 검증 결과 QT-CBP는 태그 정보 비트의 중복성이 높고, 태그 수가 많을 때 QT에 비해 뚜렷한 성능 개선이 있었다.

• 한국통신학회논문지
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• 제33권8A호
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• pp.805-814
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• 2008

Both EPCglobal Generation-2 (Gen2) for passive RFID systems and Intelleflex for semi-passive RFID systems use probabilistic slotted ALOHA with Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. A better tag anti-collision algorithm can reduce collisions so as to increase the efficiency of tag identification. In this paper, we introduce and analyze the estimation methods of the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose two new tag anti-collision algorithms, which are Chebyshev's inequality (CHI) algorithm and hybrid Q algorithm, and compare them with the conventional Q algorithm and adaptive adjustable framed Q (AAFQ) algorithm, which is mentioned in Part I. The simulation results show that AAFQ performs the best in Gen2 scenario. However, in Intelleflex scenario the proposed hybrid Q algorithm is the best. That is, hybrid Q provides the minimum identification time, shows the more consistent collision ratio, and maximizes throughput and system efficiency in Intelleflex scenario.

• 자동차안전학회지
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• 제5권1호
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• pp.5-10
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• 2013

This paper describes a Forward Collision Warning (FCW) system based on the radar driven fusion with camera. The objective of FCW system is to provide an appropriate alert with satisfying the evaluation scenarios of US-NCAP and a driver acceptance. For this purpose, this paper proposed a data fusion algorithm and a collision warning algorithm. The data fusion algorithm generates information of fusion target depending on the confidence of camera sensor. The collision warning algorithm calculates indexes and determines an appropriate alert-timing by using analysis results of manual driving data. The FCW system with the proposed data fusion and collision warning algorithm was investigated via scenarios of US-NCAP and a real-road driving. It is shown that the proposed FCW system can improve the accuracy of an alarm-timing and reduce the false alarm in real roads.