• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.113-116
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• 2015

Generally, in the railway vehicle the driving force of gravity happens by the high-speed running and the repetitive impulse cause the degradation and the malfunction phenomenon shows differently because the durability of each component changes according to the internal and external causes. The maintenance of propulsion control device which is played the very important role as to the stable service of the railway vehicle is greatly important among them. Therefore maintenance training propulsion control device simulator is needed to maximize learning through repetition and improve the maintenance practical skills training. This paper designed the railway vehicle running device with a miniature for the railway vehicle maintenance training and developed a propulsion control device simulator equipped the imitation steering wheel.

• 한국정밀공학회지
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• 제20권9호
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• pp.100-108
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• 2003

This paper proposes a flywheel hybrid vehicle to solve the energy crisis problem by the exhaustion of a fossil fuel and air pollution for the conservation of environment. The proposed flywheel hybrid vehicle is composed of an accumulator and a flywheel as the energy generation and storage component and three variable displacement hydraulic pump/motors as the energy transfer devices. Flywheel has the characteristics of high energy density and easy energy absorption and consumption. The effectiveness of the energy-saving of the proposed flywheel hybrid vehicle is verified by simulation using Matlab/simulink. First of ail, analytical modeling for the flywheel hybrid vehicle is presented and simulations are performed based on the experimental efficiency data of a variable displacement pump/motor. The results of the simulation show that the effect of energy savings is realized by the proposed hybrid vehicle in 3 different city driving patterns.

• 한국지능시스템학회논문지
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• 제19권3호
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• pp.375-380
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• 2009

본 논문에서는 자계기반 무인주행 차량을 위한 조향장치를 설계하고 개발하였다. 자계기반 무인주행 시스템에서 가장 중요한 것은 자계도로를 따라 주행할 때 차량의 방향을 제어하는 조향장치이다. 본 논문에서는 조향각 제어를 위해 조향제어장치의 메커니즘을 설계하고 스텝모터의 속도 제어를 위해 새로운 속도 추종 주파수 제어 방법을 적용하였다. 개발된 조향장치의 실용성을 입증하기 위하여 개발된 시스템을 자계기반 무인주행 차량에 적용하고 주행실험을 수행하고 분석하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.613-616
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• 2012

A multi body simulation (MBS) model is developed for predicting the impact harshness of the vehicle. Impact harshness is the vehicle performance to evaluate the impulsive vibration behavior during driving over an obstacle of the road. Thus, the approach is simulated on the time domain for considering the transient behavior of the vehicle. The validity of vehicle component modeling of bushes, dampers and structure flexibilities is verified. The simulations are compared with the test results in both of vertical and longitudinal directions. In particular, the vertical vibration of the vehicle is significantly affected by the body flexibility. Through the sensitivity analysis, main factors for the impact harshness performance are investigated.

• 자동차안전학회지
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• 제5권2호
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• pp.51-56
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• 2013

In vehicle's door wiring harness (W/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. An opening/closing member of a vehicle is attached to a vehicle by a hinge in a manner enabling easy opening and closing of the opening/closing member. Such members include doors, such as side-doors and rear doors, and other opening/closing members, such as trunk lids. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness(W/H) in vehicle's door structures for durability problem. The Finite elements analysis for door wiring harness(W/H) is used for residual stresses and dimensional stability with bending flexible. Durability test data for slam test specimens were compared with the numerical predicted fatigue life for verification. The final testing of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.519-527
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• 2020

Dynamic analysis of a vehicle-track coupling system is important to structural design, damage detection and condition assessment of the structural system. Deterministic analysis of the vehicle-track coupling system has been extensively studied in the past, however, the structural parameters of the coupling system have uncertainties in engineering practices. It is essential to treat the parameters of the vehicle-track coupling system with consideration of uncertainties. In this paper, a method for predicting the bounds of the vehicle-track coupling system responses with uncertain parameters is presented. The uncertain system parameters are modeled as fuzzy variables instead of conventional random variables with known probability distributions. Then, the dynamic response functions of the coupling system are transformed into a component function based on the high dimensional representation approximation. The Lagrange interpolation method is used to approximate the component function. Finally, the bounds of the system's dynamic responses can be predicted by using Monte Carlo method for the interpolation polynomials of the Lagrange interpolation function. A numerical example is introduced to illustrate the ability of the proposed method to predict the bounds of the system's dynamic responses, and the results are compared with the direct Monte Carlo method. The results show that the proposed method is effective and efficient to predict the bounds of the system's dynamic responses with fuzzy variables.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.235-242
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• 2021

Unmanned Aerial Vehicles (UAVs), which were used for military purposes, are gradually expanding their application fields under the influence of electrification and digitalization. Starting from the field of aerial imaging and Intelligence Surveillance and Reconnaissance (ISR) mission, nowadays the possibility of Urban Air Mobility (UAM), which transports passengers and cargo with drones, is widely under discussion. In order to occupy the rapidly growing global unmanned aerial vehicle market in advance, it is necessary to secure core technologies and develop key UAVs components based on the new technologies. In the navigation field, it is necessary to secure a precise position with guaranteed reliability and continuity, unrelated to the operating environments. The reliability and continuity should be secured in the algorithm level and in the H/W component levels also. In order to achieve this technical goal, the Ministry of Science and ICT has launched the 'Unmanned Vehicle Core Technology Research and Development Program' in 2019 to support the R&D on the unmanned vehicle technologies. In this paper, authors introduce the unmanned vehicle core technology research and development program to the related researchers. The authors summarize the backgrounds of the program and show the technological tasks and objectives on the sub-programs in the unmanned vehicle navigation program. We present the program schedules especially focused on the test and evaluation of the developed technologies and components.

• 한국정보전자통신기술학회논문지
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• 제6권1호
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• pp.6-17
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• 2013

최근 들어 기존의 녹색 바탕의 차량 번호판에서, 흰색 바탕의 신 차량 번호판으로 교체되고 있다. 하지만, 아직 기존의 차량 번호판이 신 차량 번호판으로 전면 교체 되지 않아 두 번호판 모두 사용되고 있기 때문에 주차 관리 시스템, 속도위반, 신호 위반 등 무인 카메라를 이용한 시스템에서, 기존 차량 번호판과 신 차량 번호판 특징에 맞는 인식 시스템이 요구된다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 기존의 녹색 번호판과 흰색 번호판 모두를 추출하고 인식 할 수 있는 알고리즘에 관한 연구를 수행하였다. 다양한 환경에서 획득한 차량 영상으로부터 번호판 영역을 추출하기 위하여 형태학적 특징을 이용하였고, 추출된 번호판 영역의 수평, 수직 히스토그램과 문자의 상대적 위치 정보를 이용하여, 문자를 분리하였다. 최종적으로, 분리된 문자를 인식하기 위해 주성분 분석법(PCA : Principal Component Analysis)과 선형 판별 분석법(LDA : Linear Discriminant Analysis)을 적용하여 인식 시스템을 구성하였다. 실험 결과, 불규칙한 조명 상태에서도 상대적으로 높은 추출률과 문자 인식률을 나타내었다.

• 한국임상수의학회지
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• 제33권5호
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• pp.278-285
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• 2016

Epidemiological studies have shown the association between transportation of live animals and the potential transmission of infectious disease between premises. This finding was also observed in the 2014-2015 foot-and-mouth disease (FMD) outbreak in Korea. Furthermore, slaughterhouses played a key role in the global spread of the FMD virus during the epidemic. In this context, in-depth knowledge of the structure of direct and indirect contact between slaughterhouses is paramount for understanding the dynamics of FMD transmission. But the social network structure of vehicle movements to slaughterhouses in Korea remains unclear. Hence, the aim of this study was to configure a social network topology of vehicle movements between slaughterhouses for a better understanding of how they are potentially connected, and to explore whether FMD outbreaks can be explained by the network properties constructed in the study. We created five monthly directed networks based on the frequency and chronology of on- and off-slaughterhouse vehicle movements. For the monthly network, a node represented a slaughterhouse, and an edge (or link) denoted vehicle movement between two slaughterhouses. Movement data were retrieved from the national Korean Animal Health Integrated System (KAHIS) database, which tracks the routes of individual vehicle movements using a global positioning system (GPS). Electronic registration of livestock movements has been a mandatory requirement since 2013 to ensure traceability of such movements. For each of the five studied networks, the network structures were characterized by small-world properties, with a short mean distance, a high clustering coefficient, and a short diameter. In addition, a strongly connected component was observed in each of the created networks, and this giant component included 94.4% to 100% of all network nodes. The characteristic hub-and-spoke type of structure was not identified. Such a structural vulnerability in the network suggests that once an infectious disease (such as FMD) is introduced in a random slaughterhouse within the cohesive component, it can spread to every other slaughterhouse in the component. From an epidemiological perspective, for disease management, empirically derived small-world networks could inform decision-makers on the higher potential for a large FMD epidemic within the livestock industry, and could provide insights into the rapid-transmission dynamics of the disease across long distances, despite a standstill of animal movements during the epidemic, given a single incursion of infection in any slaughterhouse in the country.

• 한국항해항만학회지
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• 제35권3호
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• pp.197-204
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• 2011

회류수조에서의 대각도 정적(static) 모형실험을 통해 Manta형 무인잠수체에 작용하는 동유체력을 측정하였으며, 동유체력에 미치는 Reynolds수의 영향을 고찰하였다. 이를 위해 동유체력을 cross-flow drag과 양력(lift force)으로 성분 분석을 하였으며, 양력 성분에는 Reynolds수의 영향을 무시하고, cross-flow drag 성분에만 Reynolds수의 영향을 고려하였다. 그 후 이들 두 성분을 다시 합성함으로써 실물 무인잠수정에 작용하는 동유체력의 추정 기법을 제시하였다.