• 오토저널
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• 제13권4호
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• pp.76-84
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• 1991

The off-road tractive performance of tracked vehicles can be evaluated in terms of soil thrust, motion resistance and drawbar pull. The ability to predict accurately ground pressure distribution under track is of importance since the vehicle sinkage and motion resistance are closely related to it. While the formulation of the method for predicting ground pressure distribution follows closely in spirit the ideas outlined for the terrain with linear pressure- sinkage relation case by Garber and Wong, the analysis of various terrain stiffness is magnified by numerical implementation procedure. The effects of soil parameters on tractive forces can be introduced through the terrain-track interaction such as pressure-sinkage and shearing characteristics. It is illustrated by determining the drawber pull-slip relation and corresponding ground pressure distribution for the terrains typically chosen and by comparing the results with the conventional ones based on normal ground pressure. The factorial experiment method is finally adopted for checking the sensitivity of the values of soil parameters on the drawbar pull.

• 제어로봇시스템학회논문지
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• 제15권4호
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• pp.372-378
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• 2009

For effective mobility control of unmanned ground vehicles in outdoor off-road environments, terrain cover classification technology using passive sensors is vital. This paper presents a novel method far terrain classification based on color and texture information of off-road images. It uses a neural network classifier and wavelet features. We exploit the wavelet mean and energy features extracted from multi-channel wavelet transformed images and also utilize the terrain class spatial coordinates of images to include additional features. By comparing the classification performance according to applied features, the experimental results show that the proposed algorithm has a promising result and potential possibilities for autonomous navigation.

• 산업기술연구
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• 제30권B호
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• pp.75-81
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• 2010

This paper presents the development of LED street light lamp which is controled by central command system. This system includes a lamp unit controller, data repeater and command repeater as well as the LED lamps. These devices enable the individual power control and partial on/off control of the LED lamps by the control repeater through full duplex communication line. Also, they have the ability to control the brightness and period of on/off timing by detecting the car's existence. As a result of this development, it is founded that the performances of the system have been satisfied to apply for the actual road test.

• International Journal of Precision Engineering and Manufacturing
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• 제8권3호
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• pp.3-7
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• 2007

There have been numerous studies directed toward the development of driving mechanisms for off-road mobility and rescue robots. To achieve surveillance, reconnaissance, and rescue, it is necessary for robots to have a driving mechanism that can handle off-road environments, We propose a new type of single-track driving mechanism with a variable geometry for a rescue robot, This mechanism has a symmetric configuration so that the robot can advance in two directions and also remain operable when overturned. By transforming its geometry, the robot can reduce energy consumption in steering and rotating as well as maximize its ability to climb obstacles such as stairs. The robot is also designed to have a compact size and low center of gravity to facilitate driving when on a set of stairs. In this paper, we analyzed the design parameters of the robot for the four phases of climbing stairs and determined the specifications needed to enhance its adaptability.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.343-346
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• 2005

In this paper a power conditioning system suitable for the fuel cell powered off-road vehicle is proposed. The proposed system employs a Proton Exchange Membrane Fuel Cell stack combined with boost converter, a super capacitor module combined with hi-directional buck-boost converter, a 4-quadrant DC chopper and a permanent magnet DC motor. The momentary overload condition occurring during the motor starting is handled by the energy stored in the supercapacitor module. Also, the regenerative energy can be stored in the supercapacitor module by operating the system in either buck or boost mode. This capability gives the system designer the higher flexibility in designing the system and assures the lower cost of the system. The validity and feasibility of the proposed system is proven by the computer simulation.

• 한국ITS학회 논문지
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• 제8권5호
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• pp.114-120
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• 2009

In outdoor visible light communication channels and LED road illumination communications for the intelligent transport systems (ITS), inter symbol interference (ISI) due to multipath propagation prevents high data rate transmission. Indoor wireless optical communication systems utilizing white LED lights and on the road illumination have been studying about it. Generally, plural lights are installed in room and considered to the traffic information system using existing LED traffic lights. Therefore, their optical path difference must be considered. In this paper, the influence of an optical path difference has been investigated and two approaches against this problem are introduced. One uses on-off keying, return-to-zero (OOK-RZ) coding and the other uses optical orthogonal frequency division multiplexing(OFDM).

• 한국자동차공학회논문집
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• 제2권3호
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• pp.105-112
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• 1994

A computer program was developed for the simulation of mobility and tractive performance of tracked off-road vehicles. Input parameters for the simulation involve those characterizing track and power drive line of a vehicle and soil conditions upon which the vehicle operates. The simulation predicts tractive performance in terms of soil thrust and motion resistance of track device and mobility performance in terms of the maximum speed, time-distance and time-speed relation that a vehicle can obtain under the given soil conditions. It also determines whether or not the vehicle can move in those conditions. An example of performing simulation was presented and its results showed that the performance prediction was reasonably in a good agreement with the published data.

• 한국군사과학기술학회지
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• 제25권6호
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• pp.606-616
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• 2022

Semantic segmentation in autonomous driving for unstructured environments is challenging due to the presence of uneven terrains, unstructured class boundaries, irregular features and strong textures. Current off-road datasets exhibit difficulties like class imbalance and understanding of varying environmental topography. To overcome these issues, we propose a deep learning framework for semantic segmentation that involves a pooled class semantic segmentation with five classes. The evaluation of the framework is carried out on two off-road driving datasets, RUGD and TAS500. The results show that our proposed method achieves high accuracy and real-time performance.

• 정보보호학회논문지
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• 제31권4호
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• pp.715-729
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• 2021

비트코인은 분산되고 투명하며 강력한 암호화를 통해 데이터 수정이 불가능한 암호화폐 중 하나이다. 그러나 익명성으로 인해 다크웹 등에서 불법 거래를 위한 지불 수단으로 사용되기도 한다. 이 문제를 해결하기 위해 비트코인 트랜잭션의 특성을 기반으로 하는 클러스터링 기법이 제안되었으나 기존 휴리스틱 기법에서는 여전히 클러스터링 되지 못하고 있는 경우가 존재한다. 이러한 거짓 부정을 줄이기 위해 비트코인 트랜잭션의 특성뿐만 아니라 오프체인 데이터를 이용한 휴리스틱을 제안한다. 우리는 오프체인 데이터를 수집하고 활용하기 위해 Silk Road 4의 리뷰 데이터를 분석하여 리뷰 데이터의 31.68%가 실제 비트코인 트랜잭션으로 매치시킬 수 있음을 발견했고 수집된 데이터에 대해 91.7%까지 거짓 부정을 줄일 수 있었다.

• 드라이브 ㆍ 컨트롤
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• 제16권3호
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• pp.94-102
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• 2019