• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.121-128
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• 2021

In this paper, we propose a path generation and tracking algorithm of an unmanned air vehicle in a two-dimensional plane given the initial and final points. The path generation algorithm using the Dubins curve proposed in this work has the advantage that it can be applied in real time to an unmanned air vehicle. The path tracking algorithm is an algorithm similar to the line-of-sight induction algorithm. In order to efficiently control the direction angle, a gain related to the look ahead distance concept is introduced. Most of UAVs have the limited maximum curvature due to the structural constraints. A numerical simulation is conducted to follow the path generated by the sliding mode controller considering the angular velocity limit. The path generation and tracking performance is verified by comparing the suggested controller with conventional control techniques.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.187-191
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• 2012

This paper deals with a safe climbing path planning for unmanned automatic vehicles. Unlike the existing path planning schemes, the safety is the highest priority for our approach. To achieve this, the global potential field which includes a dangerous zone as well a given terrain information is generated, and the way-points are determined by using image processing such as the erosion operation. The proposed method can reduce the computation effort and the amount of information, and provide the safe climbing path which is similar to human's intuition.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.2
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• pp.1-8
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• 2019

Optimal path planning refers to find the safe route to the destination at a low cost, is a major problem with regard to autonomous navigation. Sampling Based Planning(SBP) approaches, such as Rapidly-exploring Random Tree Star($RRT^*$), are the most influential algorithm in path planning due to their relatively small calculations and scalability to high-dimensional problems. $RRT^*$-Smart introduced path optimization and biased sampling techniques into $RRT^*$ to increase convergent rate. This paper presents an improvement plan that has changed the biased sampling method to increase the initial convergent rate of the $RRT^*$-Smart, which is specified as m$RRT^*$-Smart. With comparison among $RRT^*$, $RRT^*$-Smart and m$RRT^*$-Smart in 2 & 3-D environments, m$RRT^*$-Smart showed similar or increased initial convergent rate than $RRT^*$ and $RRT^*$-Smart.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5464-5488
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• 2019

The multi-population genetic algorithm in multi-target paths coverage has become a top choice for many test engineers. Also, information sharing strategy can improve the efficiency of multi-population genetic algorithm to generate multi-target test data; however, there is still space for some improvements in several aspects, which will affect the effectiveness of covering the target path set. Therefore, a multi-target paths coverage strategy is proposed by improving multi-population genetic algorithm based on individual information sharing among populations. It primarily contains three aspects. Firstly, the behavior of the sub-population covering corresponding target path is improved, so that it can continue to try to cover other sub-paths after covering the current target path, so as to take full advantage of population resources; Secondly, the populations initialized are prioritized according to the matching process, so that those sub-populations with better path coverage rate are executed firstly. Thirdly, for difficultly-covered paths, the individual chromosome features which can cover the difficultly-covered paths are extracted by utilizing the data generated, so as to screen those individuals who can cover the difficultly-covered paths. In the experiments, several benchmark programs were employed to verify the accuracy of the method from different aspects and also compare with similar methods. The experimental results show that it takes less time to cover target paths by our approach than the similar ones, and achieves more efficient test case generation process. Finally, a plug-in prototype is given to implement the approach proposed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10b
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• pp.60-64
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• 2000

This examination of vegetation is conducted from lune to Oct. 1999 through on the spot survey, centering on the habitat of Abies koreana around Imgeolryeong, langteomok, and Jeseokbong in Mt Jiri and Yeongsil path and Seongpanak path in Mt. Halla. Species composition tables of the Abies koreana community by altitude and slope in Mt. Jiri and Mt. Halla are made based on the community composition tables examined in quadrat. The Abies koreana-Saso quelpaertensis community in a west slope of Mt. Halla is found that Abies koreana of 4-6m in height forms subtree layer and that of 8-9m in height the tree layer and it reflects a difference between community structure by slope and main composition species. While the tree layer of Abies koreana community is 12-14 in height around the area of 1, 290-1, 560m above the sea of Imgeolryong and path from Baekmudong to Jangteomok, it is 8-12m in height in the area of 1, 680-1, 780m above the sea of path from Jangteomok to Jeseokbong. It means that community structure depends on area and attitude. This study finds out that commonly appearing composition species similar to coverage and presence are Lepisorus thunberianus, Quercus mongolica, Soidago virga-aurea var. asiatica, Ligularia fischeri, Carex lanceolata, Clintonia udensis, Magnolia sieboldii, Betula ermani, Acer Pseudo-sieboldianum, As soil environment of surveyed area, pH of surveyed spots is similar in Mt. Jiri and Mt. Halla, electrical conductvity is higher in Mt Jiri, and contents of organic matter is relatively higher in a west slope of Mt. Jiri and Mt. Halla and lower in their south and west slopes. Contents of organic matter and total nitrogen show that the area of 1, 550m above the sea in a west slope of Mt. Halla is some higher. For pH and contents of total nitrogen and organic matter, Mt. Halla is higher than Mt. Jiri but for electrical conductivity , Mt. Jiri is relatively higher than Mt. Halla.

• Plant Resources
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• v.3 no.2
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• pp.138-147
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• 2000

This examination of vegetation is conducted from June to Oct. 1999 through on the spot survey, centering on the habitat of Abies koreana around Imgeolryeong, Jangteomok, and Jeseokbong in Mt Jiri and Yeongsil path and Seongpanak path in Mt. Halla. Species composition tables of the Abies koreana community by altitude and slope in Mt. Jiri and Mt. Halla are made based on the community composition tables examined in quadrat. The Abies koreana-Saso quelpaertensis community in a west slope of Mt. Halla is found that Abies koreana of 4-6m in height forms subtree layer and that of 8-9m in height the tree layer and it reflects a difference between community structure by slope and main composition species. While the tree layer of Abies koreana community is 12-14 in height around the area of 1,290-1,560m above the sea of Imgeolryong and path from Baekmudong to Jangteomok, it is 8-12m in height in the area of 1,680-1,780m above the sea of path from Jangteomok to Jeseokbong. It means that community structure depends on area and attitude. This study finds out that commonly appearing composition species similar to coverage and presence are Lepisorus thunberianus, Quercus mongolica, Solidago virga-aurea var. asiatica, Ligularia fischeri, Carex lanceolata, Clintonia udensis, Magnolia sieboldii, Betula ermani, Acer pseudo-sieboldianum. As soil environment of surveyed area, pH of surveyed spots is similar in Mt. Jiri and Mt. Halla, electrical conductivity is higher in Mt Jiri, and contents of organic matter is relatively higher in a west slope of Mt. Jiri and Mt. Halla and lower in their south and west slopes. Contents of organic matter and total nitrogen show that the area of 1,550m above the sea in a west slope of Mt. Halla is some higher. For pH and contents of total nitrogen and organic matter, Mt. Halla is higher than Mt. Jiri but for electrical conductivity, Mt. Jiri is relatively higher than Mt. Halla.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1216-1223
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• 2018

As field of application of AMI, AMR uses the power line as the primary means of communication. PLC has a big merit without installation of the new network for communication in a field using the power line which is the existing equipment. However, there is a serious obstacle in commercialization for the instability by noise and communication environment. Therefore, the technical method for maintaining the communication state which overcome such demerit and was stabilized is required essentially. PLC routing technology is applied with the alternative plan now. The routing technology currently managed by field includes many problems by applying the algorithm of an elementary level. PLC routing path search problem can be modeled with the problem of searching for optimal solution as similar to such as optimal routing problem and TSP(Travelling salesman problem). In this paper, in order to search for a PLC routing path efficiently and to choose the optimal path, GA(Genetic Algorithm) was applied. Although PLC was similar in optimal solution search as compared with typical GA, it also has a difference point by the characteristic of communication, and presented the new methodology over this. Moreover, the validity of application technology was verified by showing the experimental result to which GA is applied and analyzing as compared with the existing algorithm.

• 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 Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.143-149
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• 2011

In this paper, IIR structures are proposed to reduce the computation complexity of the secondary-pass estimation in active noise control(ANC) systems. However, there are stability problems of using IIR models to reduce the computation complexity in ANC systems. To overcome these problems, we propose a stabilizing procedure of recursive least mean squares (RLMS) algorithms for eatimating the parameters of IIR models of the secondary path transfer functions. The multichannel ANC systems are implemented by using the TMS320C6713 DSP board to test the performance of computation complexity and stability of the proposed methods. Comparing the IIR filters with the FIR filters, the IIR filters can reduce 50[%] of the computation and obtain similar noise reduction result.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.3
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• pp.17-26
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• 1998

Shortest path problem in road network with turn penalties and prohibitions frequently arises from various transportation optimization models. In this paper, we propose a new algorithm for the shortest Path problem with turn prohibitions and delays. The proposed algorithm maintains distance labels of arcs, which is similar to labels of nodes of Dijkstra's algorithm. Fibonacci heap implementation of the proposed algorithm solves the problem in O(mn ＋ mlogm). We provide a new insight in transforming network with turn penalties and prohibitions into another network in which turn penalties and prohibitions are implicitly considered. The proposed algorithm is implemented using new data structure and compared with Ziliaskopoulos' algorithm. Computational results show that the proposed algorithm is very efficient.