• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.487-491
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• 2010

In this paper we propose a new single-query path planning algorithm for working well in high-dimensional configuration space. With the notice of the similarity between single-query algorithms with exploration algorithms, we propose a new path planning algorithm, which applies the Remembering Exploration method, which is one of exploration algorithms, to a path-planning problem by selecting a node from a roadmap, finding out the neighbor nodes from the node, and then inserting the neighbor nodes into the roadmap, recursively. For the performance comparison, we had experiments in 2D and 3D environments and compared the time to find out the path. In the results our algorithm shows the superior performance than other path planning algorithms.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.219-222
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• 2002

본 논문에서는 미지의 환경에서 이동로봇의 자율 주행이 가능하도록 비전 시스템과 퍼지규칙을 이용한 경로 설정과 장애물 회피를 위한 알고리즘을 소개 하고자 한다. 한편 원격지에서도 로봇의 움직임을 파악할 수 있도록 인터넷을 통한 원격운용 기능을 추가함으로써 로봇의 효율적인 운용이 가능하도록 하였다. 소벨 연산자를 이용한 장애물의 윤곽선 추출과 퍼지규칙을 이용하여 경로 계획과 장애물 회피를 위한 알고리즘을 생성하였으며, 컴퓨터 시뮬레이션으로 그 효율성을 검증하였다. 또한 실제 이동 로봇을 제작하여 실험한 결과에서도 제안된 알고리즘이 우수한 성능을 발휘함을 확인할 수 있었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.3
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• pp.157-164
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• 2022

In this paper, we describe how to implement the mountainous terrain, radar, and air defense network for UAV path planning in a 3-D environment, and perform path planning and re-planning using the PRM algorithm, a sampling-based path planning algorithm. In the case of the original PRM algorithm, the calculation to check whether there is an obstacle between the nodes is performed 1:1 between nodes and is performed continuously, so the amount of calculation is greatly affected by the number of nodes or the linked distance between nodes. To improve this part, the proposed LineGridMask method simplifies the method of checking whether obstacles exist, and reduces the calculation time of the path planning through parallelization. Finally, comparing performance with existing PRM algorithms confirmed that computational time was reduced by up to 88% in path planning and up to 94% in re-planning.

• The Journal of the Acoustical Society of Korea
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• v.34 no.5
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• pp.377-384
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• 2015

An active noise control (ANC) algorithm for noise canceling headphone is proposed. In this study, the feedback ANC operated with the filtered-x least mean square algorithm (FxLMS) algorithm is used to attenuate the undesired noise. Also an adaptive residual music canceller (RMC) is proposed for enhancing the accuracy of the reference signal of the feedback ANC. Simulation results show that a high quality of music sound can be consistently achieved in a time-varying secondary path situation.

• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.4
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• pp.27-35
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• 1998

Navigation is a method to direct a mobile robot without collision when traversing the environment. This is to reach a destination without getting lost. In this paper, global and local path planning in fixed obstacle and moving obstacle using genetic algorithm are presented. First, mobile robot searches optimal global path using genetic algorithm without falling into local minima. Then if it finds a unknown obstacle, it searches new path without crashing obstacle. Also if there is a moving obstacle, mobile robot searches new optimal path without colliding with the obstacles. Various simulation results show the proposed algorithm can search a shortest path effectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.11
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• pp.809-817
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• 2022

The development of unmanned robots and UAVs has increased the need for path planning methods such as RRT^* algorithm. It mostly works well in various environments and is utilized in many fields. A lot of research has been conducted to obtain a better path in terms of efficiency through various modifications to the RRT^* algorithm, and the performance of the algorithm is continuously improved thanks to these efforts. In this study, a method using the limitation of sampling range is proposed as an extension of these efforts. Based on the idea that a path passing close to obstacles is similar to the optimal path in obstacle environments, nodes are produced around the obstacle. Also, rewiring algorithm is modified to quickly obtain the path. The performance of the proposed algorithm is validated by comparative analysis of the previous basic algorithm and the generated path is tracked by a UAV's kinematic model for further verification.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.10
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• pp.29-38
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• 1999

This paper presents a new algorithm RICP(Redundancy Identification using Critical-pair Paths) to identify untestable faults in combinational logic circuits. In a combinational logic circuit, untestable faults occurred by redundancy of circuits. The redundancy of a circuit can be detected by analyzing areas of fanout stem and reconvergent gates. The untestable faults are identified by analyzing stem area using Critical-Pair path which is an extended concept of critical path. It is showed that RICP is better than FIRE(Fault Independent REdundancy identification) algorithm in efficiency. The performance of both algorithms was compared using ISCAS85 bench mark testing circuits.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.632-635
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• 2015

Proposal algorithm in this thesis introduced cells, units of router group, for distributed processing of previous genetic algorithm. This thesis presented ways to reduce search delay time of overall network through cell-based genetic algorithm. As a result of performance analysis comparing with existing genetic algorithm through experiments, the proposal algorithm was found superior in terms of costs and delay time. Furthermore, time for routing an alternative path was reduced in proposal algorithm, in case that a network was damaged in existing optimal path algorithm, Dijkstra algorithm, and the proposal algorithm was designed to route an alternative path faster than Dijkstra algorithm, as it has a 2nd shortest path in cells of the damaged network. The study showed that the proposal algorithm can support routing of alternative path, if Dijkstra algorithm is damaged in a network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2B
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• pp.21-26
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• 2005

A routing algorithm using the Hopfield Neural Netork (HNN) is proposed in this paper. The proposed algorithm modifies the energy function for achieving the optimality of the solution and higher convergence rate. Experimental results show that the proposed algorithm outperforms convensional methods both in optimality and convergence.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.417-419
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• 2010

본 논문에서는 최적화 문제를 해결하는 기법의 하나인 유전자 알고리즘을 이용하여 모든 노드를 탐색하여 최적의 경로를 도출하는 최적화 경로 탐색 알고리즘을 제안한다. 경로를 도출하기 위해 중간 경로 노드로부터 출발지 노드 및 도착지 노드까지의 거리를 측정하여 개체를 생성한다. 출력 노드들을 도출하기 위해 생성된 개체를 적합도 함수에 적용하여 적합도를 계산한다. 계산된 적합도 값에 따라 교배를 할 노드 및 교배 지점(비트단위)을 선택한다. 선택되어진 교배와 교배 지점을 이용하여 개체들을 교배한다. 교배를 통해 새로운 개체를 생성한다. 새로운 개체가 적합도 조건(이전 개체 중 최대값 $^*\;2$)에 만족한다면 출력 노드로 도출하고, 다음 출력 노드를 도출할 때의 출발지 노드로 선택되어진다. 이러한 과정을 반복하여 모든 출력 노드를 도출한다. 제안된 방법을 실험한 결과, 순차 방식과 난수를 이용한 경우보다 제안된 방법이 효율적인 것을 확인하였다.