• 한국철도학회논문집
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• 제15권1호
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• pp.9-16
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• 2012

철도차량의 탈선은 발생 시 대형사고로 이어질 수 있어, 철도차량의 주행안전 확보 문제는 철도운영기관 및 시설기관의 주요 현안 사항이다. 현재 대차의 동적 안정성 특성 시험은 대차 주행시험대라는 시험설비를 이용하여 시험을 하고 있다. 그러나 실물을 대상으로 한 실물규모의 주행시험대상에서의 동특성 시험은 시험 준비와 관련된 시험비용 및 시험소요 시간의 증가, 다양한 시험조건 설정 측면에서 어려움이 있다. 이러한 단점을 극복하고자 시험 편의성 측면에서 축소형 주행시험대를 활용하고 있으나 국내에서는 아직까지 축소대차, 축소트랙 등의 기초적인 수준의 연구가 진행되고 있다. 본 연구에서는 철도차량의 동적 거동을 예측하는 방법으로서 소형탈선시뮬레이터를 이용하여 상사기법이 적용된 1/5 축소대차의 주행안정성 시험에 대한 연구를 수행하였다. 또한, 시험데이터와 해석데이터를 비교·검증하기 위하여 상용해석프로그램을 이용하여 해석모델을 구현하고, 이를 이용하여 도향상에 따른 1/5 축소대차의 동적특성을 확인하였다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2004년도 하계종합학술발표회논문초록집
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• pp.388-388
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• 2004

• 한국전자통신학회논문지
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• 제13권4호
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• pp.827-836
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• 2018

본 연구에서는 기동 순찰대 오토바이 가상훈련 시스템 구현의 개발 기술을 바탕으로 PC를 기반으로 한 모터사이클 시뮬레이터를 개발하였다. 이 시뮬레이터는 초보의 운전교육을 비롯하여 운전자 인자연구, 그리고 고급 모델에서나 볼 수 있는 ABS와 같은 시스템 개발 등 다양한 분야에 응용될 수 있도록 개발하였다. 기동 순찰대에서 운영하고 있는 오토바이의 중량이 400Kg 이상으로 사전 연습이 없이는 업무 특성상 많은 위험을 내재하고 있어 이에 대한 최적의 시뮬레이터의 개발과 구성에 대한 연구 필요성에 따라 주의 분산, 상시 출동태세 유지에 따른 정신적 육체적 스트레스, 비상 출동 상황에서의 시간적 압박 등을 극복할 수 있는 가상훈련 시스템 구현하고 그 활용성에 대한 연구를 수행하였다. 모터사이클 시뮬레이터를 현실감 있게 직접 운전하고 있다는 느낌을 받도록 하기 위해서는 운전자와 시뮬레이터 사이에서 상호 신뢰성 있는 신호의 전달 및 조작 느낌이 중요하다. 이를 위해서 실차와 동일한 조작 느낌을 생성하기 위하여 실차의 각 서브시스템이 모터사이클 시뮬레이터에 그대로 적용될 수 있는 방법에 대한 연구를 수행하여 시스템을 구축하였으며, 이러한 결과를 바탕으로 운전자에게 현실감 있는 조작 느낌을 제공할 수 있는 피드백 큐 생성 방법을 개발하였다.

• 한국멀티미디어학회논문지
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• 제11권8호
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• pp.1146-1159
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• 2008

본 연구에서는 복셀(voxel) 단위로 물체의 햅틱 거동을 모사하는 햅틱 모델에 물리적 속성을 결정하기 위한 방법과 이를 이용한 햅틱 렌더링 구조(framework)를 제안한다. 또한 본 연구에서는 햅틱 모델에 물리적 속성을 결정하기 위해 탄성영상을 이용한다. 제안하는 방법과 기존 방법의 가장 큰 차이점은 제안하는 방법을 이용하면 원하는 물체의 물리적 속성을 쉽게 햅틱 모델에 적용하여 실제적인 햅틱 거동을 모사할 수 있다는 것이다. 본 연구에서는 또한 제안하는 방법을 평가하기 위하여 간단한 실시간 촉진 훈련 시뮬레이터를 구축한다. 구축한 시뮬레이터에서, 사용자에게 되돌려지는 힘은 제안한 방법으로 적용된 대상 물체의 물리적 속성과 상호작용 양에 따라 계산된다. 본 연구에서, 시뮬레이션 대상으로는 사람의 간을 선택하였고 간 모델은 실시간 햅틱 렌더링을 위하여 Shape-retaining Chain Linked Model(S-chain 모델)로 모델링하였다. 또한, 제안한 방법과 구축된 시스템을 이용하여 사용자가 물체를 촉진할 때 이상부분을 손쉽게 찾을 수 있는지에 대한 실험을 수행하였다. 본 연구의 실험 결과로부터, 제안하는 방법은 사용자에게 실시간으로 구별 가능한 힘을 전달해 줌을 알 수 있었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.359-365
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• 1999

We have evaluated the performance and some physical properties of 25 automotive engine oils (21 domestic and 5 imported products) which are purchased on the market to verify the API(American Petroleum Institute) or ILSAC(International Lubricant Standardization and Approval Committee) certification marks attached on the products and to determine the necessity of the quality control of the engine oils on the market. 12 test items are chosen according to API engine oil specification, which are flash point, pour point, cold cranking simulator apparent viscosity, pumping viscosity, gelation index, HTHS(High Temperature High Shear viscosity), foam, high temperature foam, filterability, volatility, high temperature deposit(TEOST), phosphorus content. We have found one product which did not meet the API specification on gelation index, one on HTHS, four on foam, and one on volatility, which implies that the quality control system is in need to check the fidelity of the certification marks attached on the engine oils being marketed. In addition, this works raises the necessity of the upgrade of the present Korean engine oil specification.

• 대한인간공학회지
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• 제30권2호
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• pp.285-290
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• 2011

Due to the ageing-related degradation in physical and cognitive abilities, the elderly have difficulty in car driving and this is related to the high rate of car accidents among them. This study investigated the kinematic characteristics of old drivers' steering in right turning at intersections by comparing with young drivers. Thirteen old(60~70) and thirteen young(20~30) drivers who participated in the experiment turned their cars right side at intersections in a driving simulator. As results, the completion time of right turning at intersection of old drivers was larger than that of young drivers. The speeds of vehicle at the beginning and ending point of the right turning area of old drivers were smaller than those of young drivers, and also the steering angle at the ending point of the turning area of the former was smaller than that of the latter. The normalized jerk of old driver's steering was significantly larger than that of young drivers. These results indicate that old drivers modify their steering movement repeatedly and take the driving strategy of avoiding risks due to their reduced physical capabilities.

• Journal of Multimedia Information System
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• 제5권1호
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• pp.47-52
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• 2018

We have developed an electromagnetic generator to bury in subcutaneous area or abdominal cavity of the birds. As we can't use a solar battery, it is extremely difficult to supply a power for subcutaneous implantation such as biosensors under the skin due to the darkness environment. We are aiming to test the antigen-antibody reaction to confirm an avian influenza. One solution is a very small generator with the electromagnetic induction coil. We attached the developed coil to chickens and pheasants and recorded the electric potential generated as the chicken walked and the pheasant flew. The electric potential generated with physical simulator is equal to or exceeds the 7 V peak-to-peak at maximum by 560/min of flapping of wings. Even if we account for the junction voltage of the diode (200 mV), efficient charging of the double-layer capacitor is possible with the voltage doubler rectifier. If we increase the voltage, other problems arise, including the high-voltage insulation of the double-layer capacitor. For this reason, we believe the power generated to be sufficient for subcutaneous area of birds. The efficiency, magnetic 2 mm in length and coil 15mm in length, if axial direction is rectified, the magnetic flux density given to the coil could calculated to 7.1 % and generated power average 0.47mW. The improvements in size and wire insulation are expected in the future.

• 한국전문물리치료학회지
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• 제10권2호
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• pp.1-10
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• 2003

This study was carried out to help the comprehensive rehabilitation of spinal cord injuries by measuring propulsion force and endurance exerted on wheelchair handrims, and predicting the differences among three different rear axle positions. The BTE (Baltimore Therapeutic Exerciser) work simulator was used on 9 paraplegia to test the force and endurance during wheelchair propulsion. The 141 large wheel of the BTE work simulator and a standard wheelchair with removed handrims were used for simulating wheelchair propulsion. The neurological and demographical characteristics of the patients were collected by personal interviews and direct examinations. The Kruskal-Wallis test was used to compare force and endurance among the groups. The strongest maximum isometric strength was produced when the rear axle of the wheelchair and the acromion process were on the same coronal plane. Although there were no significant differences statistically, moving the rear axle forward did result in greater isotonic strength. The research suggests that better functional activity of persons with paraplegia is possible when the rear axle of the wheelchair is appropriately adjusted.

• Wind and Structures
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• 제11권2호
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• pp.75-96
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• 2008

A better understanding of tornado-induced wind loads is needed to improve the design of typical structures to resist these winds. An accurate understanding of the loads requires knowledge of near-ground tornado winds, but observations in this region are lacking. The first goal of this study was to verify how well a CFD model, when driven by far field radar observations and laboratory measurements, could capture the flow characteristics of both full scale and laboratory-simulated tornadoes. A second goal was to use the model to examine the sensitivity of the simulations to various parameters that might affect the laboratory simulator tornado. An understanding of near-ground winds in tornadoes will require coordinated efforts in both computational and physical simulation. The sensitivity of computational simulations of a tornado to geometric parameters and surface roughness within a domain based on the Iowa State University laboratory tornado simulator was investigated. In this study, CFD simulations of the flow field in a model domain that represents a laboratory tornado simulator were conducted using Doppler radar and laboratory velocity measurements as boundary conditions. The tornado was found to be sensitive to a variety of geometric parameters used in the numerical model. Increased surface roughness was found to reduce the tangential speed in the vortex near the ground and enlarge the core radius of the vortex. The core radius was a function of the swirl ratio while the peak tangential flow was a function of the magnitude of the total inflow velocity. The CFD simulations showed that it is possible to numerically simulate the surface winds of a tornado and control certain parameters of the laboratory simulator to influence the tornado characteristics of interest to engineers and match those of the field.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.444-448
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• 2005

This paper presents a developing procedure of the CAN-based real-time simulator for car body control, aiming at replacing the actual W/H (Wiring Harness) and J/B(Junction Box) couple eventually. The CAN protocol, as one kind of field-bus communication, defines the lowest 2 layers of the ISO/OSI standard, namely, the physical layer(PL) and the data link layer(DLL), for which the CSMA/NBA protocol is generally adopted. For CPU, two PIC18Fxx8x's are used because of their built-in integration of CAN controller, large internal FLASH memory (48K or 64K), and their costs. To control J/B's and actuators, 2 controller boards are separately implemented, between which CAN lines communicate through CAN transceivers MCP255. A power motor for washing windshield, 1 door lock motor, and 6 blink lamps are chosen for actuators of the simulator for the first stage. For the software architecture, a polling method is used for the fast global response time despite its slow individual response time. To improve the individual response time and to escape from some eventual trapped-function loops, High/Low ports of the CPU are simply used, which increases the stability of the actuator modules. The experimental test shows generally satisfactory results in normal transmitting / receiving function and message trace function. This simulator based on CAN shows a promising usefulness of lighter, more reliable and intelligent distributed body control approach than the conventional W/H and J/B couple. Another advantage of this approach lies in the distributed control itself, which gives better performance in hard real-time computing than centralized one, and in the ability of integrating different modules through CAN.