• International Journal of Control, Automation, and Systems
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• 제1권1호
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• pp.35-42
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• 2003

This paper proposes a simple, robust, nonlinear controller based on Lyapunov stability for tracking the reference welding path and velocity of a two-wheeled welding mobile robot (WMR). The system has three degrees of freedom including two wheels and one torch slider. Torch slider motion is used for faster tracking because the welding speed is very slow. Control law is obtained from the Lyapunov control function to ensure the asymptotical stability of the system. The controller has three free parameters for adjusting the performance of the controlled system. A simple way of measuring the errors using two potentiometers is introduced. The effectiveness of the proposed controller is shown through simulation results.

• 융합신호처리학회논문지
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• 제6권4호
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• pp.182-190
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• 2005

본 논문에서는 차량을 자동으로 주차시키기 위한 시스템을 구현하고 이 시스템을 구동시키기 위한 방법론을 제시한다. 차량이 자동으로 주차하기 위해서는 첫째, 차량의 위치와 주차위치, 장애물의 위치를 파악하고 둘째, 장애물을 피하여 정확한 주차위치에 도달할 수 있는 차량의 이동 경로 산출하고 셋째, 생성된 경로를 따라 차량이 이동할 수 있도록 핸들을 제어해야 한다. 차량의 위치와 주차위치, 장애물의 위치를 판단하기 위하여 카메라로부터 입력 받은 영상의 변환을 통해 평면 지도를 생성하는 기법과 차량의 이동 모델을 통해 차량의 속도와 조향각도를 이용하여 이동한 차량의 위치를 판단하는 관성 항법 기법을 이용하였다. 차량의 이동 경로 산출에 있어서는 차량의 회전 반경을 고려한 Simple path method와 Bezier spline을 이용한 경로 수정 방법을 이용하였다. 또한, Divided arc method를 이용하여 장애물을 피하는 다양한 이동 경로를 생성하였다. 생성된 경로 중 다양한 목적함수를 만족시키는 제일 좋은 경로를 선택하기 위한 방법을 적용하여 하나의 경로를 선택하였다. 차량의 이동 경로 상에 장애물을 피해 정확한 위치에 차량을 위치시킬 수 있는 방법을 테스트 하였다. 생성된 경로를 따라 차량이 움직이기 위한 제어 기법으로는 Virtual road method을 이용하여 기계적인 시간 지연 등의 문제점을 해결하였다.

• ETRI Journal
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• 제15권3_4호
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• pp.27-34
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• 1994

There have been traditional approaches to model radio propagation path loss mechanism both theoretically ad empirically. Theoretical approach is simple to explain and effective in certain cases. Empirical approach accommodates the terrain configuration and distance between base station and mobile unit along the propagation path only. In other words, it does not accommodate natural terrain configuration over a specific area. In this paper, we propose a spatial prediction technique for the mobile radio propagation path loss accommodating complete natural terrain configuration over a specific area. Statistical uncertainty analysis is also considered.

• 대한산업공학회지
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• 제19권2호
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• pp.43-51
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• 1993

This paper describes the flow path design of unidirectional automated guided vehicle systems. The objective is to find the flow path which will minimize total travel time of unloaded as well as loaded vehicles. The allocation of unloaded vehicles is determined by applying the transportation simplex method. The problem is solved using a branch-and-bound technique. A simple illustrative example is discussed to demonstrate the procedure.

• 대한수학회논문집
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• 제29권1호
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• pp.213-218
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• 2014

J. Malkevitch defined the coded path in r-valent polytopal graphs of uniform face structure and showed many interesting properties of the coded paths. In this paper, we study the simplicity of coded paths in an m-valent planar multigraph which is not a polytopal graph.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.723-728
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• 1999

In this paper, we designed a Circular Path Built-In Self Test circuit and embedded it into a simple 8-bit microprocessor. Register cells of the microprocessor have been modified into Circular Path register cells and each register cells have been connected to form a scan chain. A BIST controller has been designed for controlling BIST operations and its operation has been verified through simulation. The BIST circuit described in this paper has increased size overhead of the microprocessor by 29.8% and delay time in the longest delay path from clock input to output by 2.9㎱.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1998년도 The Korea Society for Simulation 98 춘계학술대회 논문집
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• pp.11-16
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• 1998

The classical algorithm for solving liner network flow problems are primal cost improvement method, including simplex method, which iteratively improve the primal cost by moving flow around simple cycles, which iteratively improve the dual cost by changing the prices of a subset of nodes by equal amounts. Typical iteration/shortest path algorithm is used to improve flow problem of liner network structure. In this paper we stdudied about the implemental method of shortest path which is a practical computational aspects. This method can minimize the best neighbor node and also implement the typical iteration which is $\varepsilon$-CS satisfaction using the auction algorithm of linear network flow problem

• 한국컴퓨터정보학회논문지
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• 제14권7호
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• pp.97-103
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• 2009

본 논문의 무선 센서네트워크에서 사용할 수 있는 효율적인 라우팅 방법인 MP-DD (MultiPath-Direct Diffusion) 알고리즘을 제안한다. 기존의 DD(Directed Diffusion)에서는 하나의 경로만을 강화하여 사용하는 것과 달리 제안한 알고리즘은 다중 경로를 강화하면서, 해당 경로에 높여 있는 센서 노드의 남은 에너지 등급을 고려하여 에너지 레벨이 높은 경로에 따라 가중치를 부여하고, 몇 개의 다중경로를 이용하여 사용함으로써 에너지 소모를 감소시키고 동시에 네트워크에 전체적으로 에너지를 골고루 사용하게 할 수 있다. 시뮬레이션 결과에서는 이러한 센서 네트워크를 위한 단순한 라우팅 방법의 가능성을 증명하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.249-251
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• 2005

In this paper, an algorithm of path planning and obstacle avoidance for mobile robot is proposed. We call the proposed method Random Access Sequence(RAS) method. In the proposed method, a small region is set first and numbers are assigned to its neighbors. By processing assigned numbers all regions are covered and then the path from start to destination is selected by these numbers. The RAS has an advantage of fast planning because of simple operations. This implies that new path selection may be possible within a short time and helps a robot to avoid obstacles in any direction. The algorithm can be applied to unknown environments. When moving obstacles appear, a mobile robot avoids obstacles reactively. then new path is selected by RAS.

• 한국시뮬레이션학회논문지
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• 제8권3호
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• pp.17-28
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• 1999

Recently studies have shown that conditional branches can be accurately predicted by recording the path leading up to the branch. But path predictors are more complex and uncompatible with existing pattern branch predictors. In order to solve these problems, we propose a simple path branch predictor(SPBP) that hashes together two most recent branch instruction addresses. In addition, we propose a pattern/path hybrid branch predictor composed of the SPBP and existing pattern branch predictors. Through the trace-driven simulation of six benchmark programs, the performance improvement by the proposed pattern/path hybrid branch prediction is analysed and validated. The proposed predictor can improve the prediction accuracy from 94.21% to 95.03%.