• 한국통신학회논문지
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• 제8권3호
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• pp.83-90
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• 1983

N-Path SC追跡濾波器를 可聽周波數이상에서 硏究하였다. 먼저 전체 SC濾波器의 特性을 決定지우는 Filter Cell에 대한 解析으로 電荷方程式과 差等方程式에 의한 解析을 수행하고 커패시터와 스위치만으로 構成된 4-path와 8-path SC濾波器를 提示하였다. 다음 실제로 SC濾波器블록과 PLL블록의 構成으로 4-path와 8-path SC追跡濾波器를 각각 構成하였으며 最大應答의 移動, 커패시터比와 path數에 따른 Q와 利得(dB)의 變動, 追跡範圍등을 考察하였다.

• 로봇학회논문지
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• 제5권2호
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• pp.120-126
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• 2010

This paper presents to study the path tracking method of AGV(autonomous guided vehicle) which has a laser guidance system. An existing automatic guided vehicles(AGVs) which were able to drive on wired line only had a automatic guidance system. However, the automatic guidance systems that those used had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the laser guidance system which is consisted of a laser navigation and gyro, encoder. That is robust against noise, and flexible according to working environment through sensor fusion. The laser guidance system can do a perfect autonomous driving. However, the commercialization of perfect autonomous driving system is difficult, because the perfect autonomous driving system must recognize the whole environment of working space. Hence, this paper studied the path tracking of AGV using laser guidance system without wired line. The path tracking method is consisted of virtual path generation method and driving control method. To experiment, we use the fork-type AGV which is made by ourselves, and do a path tracking experiments repeatedly on same experimental environment. In result, we verified that proposed system is efficient and stable for actual fork-type AGV.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권1호
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• pp.87-99
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• 2015

In recent years, the development of autonomous surface vehicles has been a field of increasing research interest. There are two major areas in this field: control theory and path planning. This study focuses on path planning, and two objectives are discussed: path planning for Unmanned Surface Vehicles (USVs) and implementation of path planning in a real map. In this paper, satellite thermal images are converted into binary images which are used as the maps for the Finite Angle $A^*$ algorithm ($FAA^*$), an advanced $A^*$ algorithm that is used to determine safer and suboptimal paths for USVs. To plan a collision-free path, the algorithm proposed in this article considers the dimensions of surface vehicles. Furthermore, the turning ability of a surface vehicle is also considered, and a constraint condition is introduced to improve the quality of the path planning algorithm, which makes the traveled path smoother. This study also shows a path planning experiment performed on a real satellite thermal image, and the path planning results can be used by an USV.

• 한국컴퓨터정보학회논문지
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• 제12권6호
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• pp.131-137
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• 2007

전파가 미치지 않는 3차원 지형에서의 음영공간을 항공기가 안전하게 목적지까지 비행하는 최단 경로를 구하고자 하는 것이다. 여기서 비교적 넓은 음영공간을 다각형 형태의 볼록 다각형으로 분할하고, 분할된 볼록 다각형 내에서는 가중치 값에 따라 중간목적지까지의 경로를 찾고, 그 중간목적지를 시작점으로 하여 인접한 다각형에서 다시 목적지를 찾아가는 과정을 분할된 다각형 내에서 반복해서 최종 목적지까지의 최단 경로를 찾아가는 방법을 제안하였다. 구현은 3차원 실지형 상에서 전파가 미치지 않는 음영공간상에 Graph Growth 알고리즘의 임계값을 적용한 수정된 알고리즘을 이용하여 최단 경로를 탐색하였다. 실험에 의해 본 논문에서 제안한 방법이 효과적인 비행 궤적을 생성하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.25-29
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• 1997

In this thesis, we construct the microrobot succor system and navigate the real-time path planning and visual tracking of each robot. The system consists robots, vision system and a host computer. Because the robots are free-ranging mobile robot, it is needed to make and gallow the path. The path is planned and controlled by a host computer, ie. Supervisory control system. In path planning, we suggest a cost function which consists of three terms. One is the smoothness of the path, another is the total distance or time, and the last one is to avoid obstacles. To minimize the cost function, we choose the parametric cubic spline and update the coefficients in real time. We perform the simulation for the path planing and obstacle avoidance and real experiment for visual tracking

• 정보처리학회논문지A
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• 제8A권2호
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• pp.179-188
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• 2001

We analyze the property of candidate node set in the network graph, and propose an algorithm to decrease shortest path-finding computation time by using multiple dynamic-range queue(MDRQ) structure. This MDRQ structure is newly created for effective management of the candidate node set. The MDRQ algorithm is the shortest path-finding algorithm that varies range and size of queue to be used in managing candidate node set, in considering the properties that distribution of candidate node set is constant and size of candidate node set rapidly change. This algorithm belongs to label-correcting algorithm class. Nevertheless, because re-entering of candidate node can be decreased, the shortest path-finding computation time is noticeably decreased. Through the experiment, the MDRQ algorithm is same or superior to the other label-correcting algorithms in the graph which re-entering of candidate node didn’t frequently happened. Moreover the MDRQ algorithm is superior to the other label-correcting algorithms and is about 20 percent superior to the other label-setting algorithms in the graph which re-entering of candidate node frequently happened.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.157-163
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• 1995

This paper presents an algorithm to deternine the tool path height for rough machining of sculptured surface. To minimize rough machining of sculptured surface, it is necessary to determine the tool path heights of contour planes. the proposed algorithm searches for the height at which maximum metal removal rate is obtained. This bisection method is accomplished until all shoulder heights are within roughing tolerance. The machining experiment demonstrates the superiority of the algorithm presented in this thesis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.763-767
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• 1994

The measured vibration on a machine or a structure is shaped by the excitation waveform and the path transfer function. Mechanism diagnostics tends to focus on retrieving source featurce by minimzing the effects of the structural path, while in structural diagnostics we are more interested in minimizing source effects and retrieving path parameters. In structural diagnostics, therefore, there are experimental issues of gathering data that are independent source effects and finding a transfer function signature that reveals structural defects. This paper describes how the transfer function can be obtained more accurately by experiment using the compatibility relationship which is newly discovered.

• 한국국방경영분석학회지
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• 제26권2호
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• pp.120-130
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• 2000

The purpose of this study is to present a method for determining the k most vital arcs in shortest path problem using an evolutionary algorithm. The problem of finding the k most vital arcs in shortest path problem is to find a set of k arcs whose simultaneous removal from the network causes the greatest increase in the total length of shortest path. Generally, the problem determining the k most vital arcs in shortest path problem has known as NP-hard. Therefore, in order to deal with the problem of real world the heuristic algorithm is needed. In this study we propose to the method of finding the k most vital arcs in shortest path problem using an evolutionary algorithm which known as the most efficient algorithm among heuristics. The method presented in this study is developed using the library of the evolutionary algorithm framework and then the performance of algorithm is analyzed through the computer experiment.

• 융합보안논문지
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• 제19권3호
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• pp.3-12
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• 2019

인터넷 상의 사용자가 목적지 시스템으로 정보를 전송할 수 있도록 라우팅 정보를 서로 교환하여 라우팅 테이블을 생성하고 변화된 정보를 업데이트 해주는 라우팅 프로토콜 중 가장 중요한 프로토콜이 BGP 이다. 본 논문은 현재 사용되고 있는 BGPv4의 취약성을 이용하여 악의적인 공격과 네트워크 관리자의 실수로 발생할 수 있는 문제점을 사전에 차단하는 방법과 BGP의 대표적인 보안 취약점에 대한 공격기법인 AS-PATH 공격에 대한 실제 공격실험을 수행하여 공격기법들을 분석하고, AS-PATH 공격을 식별하는 알고리즘을 제안하였다.