http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
고속도로 ADAS 주행차량을 위한 종방향 자율주행 지원 시스템 시뮬레이터 개발
옥민환(Min-Hwan Ok) 한국정보기술학회 2019 한국정보기술학회논문지 Vol.17 No.11
Current ADAS technology has a shortcoming that the driver should assign target speeds manually to ACC when the vehicle is a leading vehicle being driven with ADAS. This work proposes a guidance system provides target speeds for leading vehicles being driven with ADAS. A framework is designed for the system functions pursuing partially autonomous driving(SAE Level 2) through V2I communication, and expected functionality with related conditions is evaluated through simulation. The proposed system conducted lowering speed range in average 6 seconds at 50% lane usage, and average 11 seconds at 80% lane usage in the simulation.
고속도로 주행차량 데이터 준실시간 처리를 위한 분산 서버 시스템의 부하이동 시뮬레이터 개발
옥민환(Min-Hwan Ok) 한국정보기술학회 2015 한국정보기술학회논문지 Vol.13 No.12
The technology progresses continuously toward an advent of future driving to pursue sharing vehicle information between vehicles and between vehicles and roadside infrastructure for driving safety. Compared to devised diverse means of driving safety through V2V communication, those through V2I communication are rare, however these have various advantages in informationizing and utilizing the entire vehicles states. A new system model is proposed to provide overall running vehicles information to all the vehicles every second via each information server, and to announce speed ranges along lanes to the vehicles constituent of the lane usage. By simulating a system of the model with sorts of parameters, the systems influence is evaluated. The simulation result shows the models applicability through marginal distances according to the vehicle speeds, and through average times available for shifting the lane according to the lane usages.
A Central Navigation of the Autonomous Vehicles in Zone-based Tessellations with Target Velocities
Min-Hwan Ok(옥민환) 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.12
The autonomous vehicles are more adaptable to traffic congestion if they join with each other in propagating the situation of traffic around, and have a potential to avoid the traffic jam if they all drive along scheduled routes given from one centralized navigation system. This work presents a central navigation for autonomous vehicles travel through a number of tessellated zones. Routes are scheduled every area, and they could be partially altered by traffic situations. Each vehicles compliance with its scheduled route is checked for every route scheduling, and the vehicle positions should be accurate in the traversal through the zone. The vehicle position is estimated with its velocity calculated by imitating autonomous driving, especially for use in the situation of unavailable communication. The estimation technique does not adopt an inertial measuring unit and the accelerometer, differently from previous works in estimating the position of a moving entity. The velocity calculated by imitating autonomous driving has the lower deviation range of errors than that by linear interpolation at a feasible reporting interval through the simulation.
초고속주행 하이퍼루프 포드의 정밀 위치측정 장치 구현 및 성능평가
옥민환(Min-Hwan Ok),최수용(Su-Yong Choi),최재헌(Jae-Heon Choe),이관섭(Kwan-Sup Lee) 한국정보전자통신기술학회 2020 한국정보전자통신기술학회논문지 Vol.13 No.5
하이퍼루프는 튜브 내를 부상한 상태로 초고속주행하는 미래형 이동 시스템으로 제안되었다. 하이퍼루프에서 달리는 포드 차량은 선형 동기모터 상에서 주행하기에 위치측정이 근본적 중요성을 가진다. 1000km/h 이상의 속도로 주행하는 포드 차량의 가속과 감속에 정밀한 위치측정이 요구되며 또한 차량간 거리 유지를 위한 속도 조절에도 요구된다. 본 논문은 laser surface velocimeter를 개량하여 새로운 범위조건의 위치측정을 시도한다. 높은 정밀도로 초고속 이동체의 위치를 측정해야 하기에 지나가는 타일의 레이저 반사율 차이 검출로 변위를 계산하는 상대위치 측정장치를 구현하여 성능시험으로 평가하였다. 500km/h 미만의 포드 속도에서 cm 단위의 정밀도로 정확한 위치 측정을 보였으며, 500km/h 이상의 포드 속도에서도 0.1% 미만의 매우 낮은 오차율로 위치측정 결과를 보여주었다. 향후 500km/h 이상에서의 오차율도 0에 수렴하도록 연구를 진행해야 한다. A futuristic locomotion system called Hyperloop is projected for driving at ulta-high speed, levitated in the tube. In hyperloop localization of pods on the linear synchronous motor is essential for pod driving. precision localization is required for acceleration and deceleration of pods driving at speed above 1,000km/h, and also required for adjusting the pod speed driving at this very-high speed to maintain inter-vehicle distance. In this work, a new scale of localization is challenged by modified laser surface velocimeter. In acceleration the speed of a virtual pod is calculated along its displacement measured by laser reflection. Under the requirement of precise localization of the pod driving at ultra-high speed, a displacement measurement device, which detects the difference in reflections from tiles passing by the pod, is developed and evaluated through performance test. Tests of pod speeds below 500km/h have showed exact localization results of the precision in centimeters, and tests of pod speeds above 500km/h have showed localization with very low error rates under 0.1%. For the measurement above 500km/h, future works would pursue the error rate converges to zero.
웹 서버 클러스터에서 Cyber Foraging 응용을 위한 비주기적 부하 갱신을 통한 부하 분산 기법
최원일,강정훈,옥민환,박명순,Choi, Won-Il,Kang, Jung-Hun,Ok, Min-Hwan,Park, Myong-Soon 한국정보처리학회 2007 정보처리학회논문지 A Vol.14 No.1
본 논문에서 웹 서버 클러스터 환경에서 웹 요청들의 분산을 위한 부하 분산 기법을 제안한다. 전통적인 주기적 부하 정보 갱신 기반의 부하 분산 기법에서는 동기화된 부하 정보와 동적 페이지에 포함된 스크립트들의 갱신 정보 때문에 Cyber Foraging 서비스 같은 동적 웹 응용프로그램에서는 적합하지 않다. 이를 해결하기 위해 Update-on-Finish 부하 분산 알고리즘은 비주기적인 부하 갱신 방법을 사용하고 있다. 웹 스위치는 비주기적인 부하 리포팅 후, 서버들의 실제 부하 정보를 알 수 있다. 그런후 실제 정보에 따라 부하 분산 스케줄을 재배열한다. 하지만 Update-on-Finish 알고리즘의 경우 부하 정보를 유지하기 위한 통신 부하가 크다는 문제점을 가진다. 본 논문에서는 각 서버가 K%의 작업을 마친 후 비주기적 부하 정보 보고를 통하여 부하 감소시킨 방법을 제안한다. 또한 서버의 처리능력이 다른 환경을 고려하여 서로 다른 threshold Ti값을 적용함으로써, 다양한 처리 능력을 가진 서버들을 위한 로드 밸런싱 알고리즘으로 확장하여 제안하고 있다. 시뮬레이션 결과에서 제안된 K-Percent-Finish Reporting 방법은 Update-on-Finish 방법보다 최소 50% 이상의 통신 부하를 감소시키면서, 기존 주기적 부하정보 갱신 기반의 관련 연구들보다 향상된 시스템 처리 능력을 보여주고 있다. This paper introduces a load-balancing algorithm focusing on distributing web requests evenly into the web cluster servers. The load-balancing algorithms based on conventional periodic load-information update mechanism are not suitable for dynamic page applications, which are common in Cyber Foraging services, due to the problems caused by periodic synchronized load-information updating and the difficulties of work load estimation caused by embedded executing scripts of dynamic pages. Update-on-Finish algorithm solves this problem by using non-periodic load-update mechanism, and the web switch knows the servers' real load information only after their reporting and then distributes new loads according to the new load-information table, however it results in much communication overhead. Our proposed mechanism improve update-on-finish algorithm by using K-Percents-Finish mechanism and thus largely reduce the communication overhead. Furthermore, we consider the different capabilities of servers with a threshold Ti value and propose a load-balancing algorithm for servers with various capabilities. Simulation results show that the proposed K-Percents-Finish Reporting mechanism can at least reduce 50% communication overhead than update-on-finish approach while sustaining better load balancing performance than periodic mechanisms in related work.
가상현실기술을 이용한 차량 및 인적사고 시뮬레이터 설계
전현규(Jun Hyun Kyu),양도철(Yang Doh Chul),옥민환(Ok Min Hwan) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-
There are always chances to make wrong decisions when personnels are suddenly exposed to unexpected accidents which can cause heavy casualties. For this reason, the technology for reproducing the accident condition to find better and effective solutions is necessary. A simulator technology based on virtual reality is regarded as an appropriate tool to reproduce accidents in safe environment. In this research, we did research on making scenarios to cope with possible accidents in urban transit, and suggested a design strategy of a simulator for analyzing and training on the accidents by visualizing them in immersive virtual environment. By using the simulator, we expect to find more effective way to handle the emergency conditions