• 한국컴퓨터정보학회논문지
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• 제20권10호
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• pp.7-13
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• 2015

Wearable device, next generation smart device, is consistently growing. The flexible display will be a kind of display in the wearable device. The flexible display technology is now evolving with end-user requirement such as portability and easy installation. Previous wearable display products still have some difficulties in manufacturing and in flexibility whole device. But it can be a flexible display with LED device and utilized in commercial area. In this paper, we propose a driver to control the LED display and implement a flexible LED display system.

• ETRI Journal
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• 제38권4호
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• pp.645-653
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• 2016

This paper demonstrates the performance of a metal-substrate power module with multiple fabricated chips for a high current electrical application, and evaluates the proposed module using a 1.5-kW sinusoidal brushless direct current (BLDC) motor. Specifically, the power module has a hybrid structure employing a single-layer heat-sink extensible metal board (Al board). A fabricated motor driver IC and trench gate DMOSFET (TDMOSFET) are implemented on the Al board, and the proper heat-sink size was designed under the operating conditions. The fabricated motor driver IC mainly operates as a speed controller under various load conditions, and as a multi-phase gate driver using an N-ch silicon MOSFET high-side drive scheme. A fabricated power TDMOSFET is also included in the fabricated power module for three-phase inverter operation. Using this proposed module, a BLDC motor is operated and evaluated under various pulse load tests, and our module is compared with a commercial MOSFET module in terms of the system efficiency and input current.

• ETRI Journal
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• 제31권3호
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• pp.247-253
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• 2009

We propose a Ku-band driver and high-power amplifier monolithic microwave integrated circuits (MMICs) employing a compensating gate bias circuit using a commercial 0.5 ${\mu}m$ GaAs pHEMT technology. The integrated gate bias circuit provides compensation for the threshold voltage and temperature variations as well as independence of the supply voltage variations. A fabricated two-stage Ku-band driver amplifier MMIC exhibits a typical output power of 30.5 dBm and power-added efficiency (PAE) of 37% over a 13.5 GHz to 15.0 GHz frequency band, while a fabricated three-stage Ku-band high-power amplifier MMIC exhibits a maximum saturated output power of 39.25 dBm (8.4 W) and PAE of 22.7% at 14.5 GHz.

• 한국도로학회논문집
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• 제11권3호
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• pp.85-95
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• 2009

2007년 경찰청 통계자료에 따르면 사업용 차량(시내, 시외, 기타버스)의 교통사고 건수는 당 해 교통사고 건수의 3.5%에 해당하지만 사업용 차량의 경우 운전자 외 다수 승객의 안전을 책임져야 하므로 더욱 심각한 사회적, 경제적 문제를 초래한다. 이러한 사업용 차량의 교통사고 감소 및 안전운전에 대한 사회적 요구에 부흥하기 위하여 디지털 주행기록계, 차량용 블랙박스 등 다양한 형태의 시스템이 사용되고 있으나, 이러한 시스템은 사고 후 차량데이터를 기반으로 위험운전여부를 분석하여 운전자를 관리하기 때문에 실시간으로 운전자를 관리하기에는 큰 한계가 있다. 또한 현재 운영되고 있는 주행기록계는 운전자에게 경고 정보를 제공하지만 실제 위험운전 여부와 상관없이 차량의 속도와 RPM정보만을 이용하여 운전자에게 경고를 제공하고 있어 효율이 매우 떨어지는 실정이다. 이에 본 연구의 선행연구에서는 차량 운전자의 운전행태에 따른 차량 동역학 데이터를 저장?판단하여 운전자에게 실시간으로 경고정보를 제공해 줄 수 있는 위험운전 판단장치를 개발하였으며, 개발된 위험운전 판단장치에서 운전자의 안전운전을 향상 시킬 수 있는 위험운전 유형에 따른 임계값을 개발하였다.

• International Journal of Automotive Technology
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• 제7권2호
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• pp.145-154
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• 2006

In the companion paper, the composition and structure of the MATDYMO (Multi-Agent for Traffic Simulation with Vehicle Dynamic Model) were proposed. MATDYMO consists of the road management system, the vehicle motion control system, the driver management system, and the integration control system. Among these systems, the road management system and the integration control system were discussed In the companion paper. In this paper, the vehicle motion control system and the driver management system are discussed. The driver management system constructs the driver agent capable of having different driving styles ranging from slow and careful driving to fast and aggressive driving through the yielding index and passing index. According to these indices, the agents pass or yield their lane for other vehicles; the driver management system constructs the vehicle agents capable of representing the physical vehicle itself. A vehicle agent shows its behavior according to its dynamic characteristics. The vehicle agent contains the nonlinear subcomponents of engine, torque converter, automatic transmission, and wheels. The simulation is conducted for an interrupted flow model and its results are verified by comparison with the results from a commercial software, TRANSYT-7F. The interrupted flow model simulation is implemented for three cases. The first case analyzes the agents' behaviors in the interrupted flow model and it confirms that the agent's behavior could characterize the diversity of human behavior and vehicle well through every rule and communication frameworks. The second case analyzes the traffic signals changed at different intervals and as the acceleration rate changed. The third case analyzes the effects of the traffic signals and traffic volume. The results of these analyses showed that the change of the traffic state was closely related with the vehicle acceleration rate, traffic volume, and the traffic signal interval between intersections. These simulations confirmed that MATDYMO can represent the real traffic condition of the interrupted flow model. At the current stage of development, MATDYMO shows great promise and has significant implications on future traffic state forecasting research.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.25-34
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• 2006

For decades, simulation technique has been well validated in areas such as computer and communication systems. Recently, the technique has been much used in the area of transportation and traffic forecasting. Several methods have been proposed for investigating complex traffic flows. However, the dynamics of vehicles and diversities of driver characteristics have never been considered sufficiently in these methods, although they are considered important factors in traffic flow analysis. In this paper, we propose a traffic simulation tool called Multi-Agent for Traffic Simulation with Vehicle Dynamics Model (MATDYMO). Road transport consultants, traffic engineers and urban traffic control center managers are expected to use MATDYMO to efficiently simulate traffic flow. MATDYMO has four sub systems: the road management system, the vehicle motion control system, the driver management system, and the integration control system. The road management system simulates traffic flow for various traffic environments (e.g., multi-lane roads, nodes, virtual lanes, and signals); the vehicle motion control system constructs the vehicle agent by using various vehicle dynamic models; the driver management system constructs the driver agent capable of having different driving styles; and lastly, the integrated control system regulates the MATDYMO as a whole and observes the agents running in the system. The vehicle motion control system and driver management system are described in the companion paper. An interrupted and uninterrupted flow model were simulated, and the simulation results were verified by comparing them with the results from a commercial software, TRANSYT-7F. The simulation result of the uninterrupted flow model showed that the driver agent displayed human-like behavior ranging from slow and careful driving to fast and aggressive driving. The simulation of the interrupted flow model was implemented as two cases. The first case analyzed traffic flow as the traffic signals changed at different intervals and as the turning traffic volume changed. Second case analyzed the traffic flow as the traffic signals changed at different intervals and as the road length changed. The simulation results of the interrupted flow model showed that the close relationship between traffic state change and traffic signal interval.

• 대한인간공학회지
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• 제34권3호
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• pp.247-264
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• 2015

Objective: The purpose of this study is to determine the priority of information presentation and the effective menu type to be placed in the center of a gauge cluster display for commercial trucks and to present a set of ergonomic designs for the gauge cluster display. Background: An effective ergonomic design is specifically needed for the development of the gauge cluster display for the commercial trucks, because more diverse and heavier information is delivered to truck drivers, compared to the information to passenger car drivers. Method: First, all the information that must be shown on the commercial truck display was collected. Then, the severity, frequency of use, and display design parameters were evaluated for those information by commercial truck drivers. Next, an analysis on the information attributes and the heuristic evaluation utilizing the display design principles were carried out. According to the results, a design alternative of the main screen to be displayed was constructed by priority. A comparative analysis between the alternative and existing main screens was also conducted to see the efficacy of the designs. Lastly, we conducted an experiment for the selection of menu type. The experiment was conducted using the driving simulator with an eye-tracking device. The independent variables were four types of the menu reflecting the commercial truck characteristics such as grid type, icon type, list type, and flow type. We measured preference, total execution time, the total duration of fixation on the gauge cluster area, and the total number of fixation on the gauge cluster area as dependent variables. Results: Four types of driver convenience information and six types of driver assistance information were selected as the information to be placed primarily on the main screen of the gauge cluster. The Grid type was the most effective among the menu types. Conclusion: In this study, the information that appears on the main screen of the display, the division of the display and the design of the menu type for commercial truck drivers were suggested. Application: This study is expected to be utilized as guidelines on the ergonomic design of a gauge cluster display for commercial trucks.

• 한국산학기술학회논문지
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• 제18권11호
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• pp.697-704
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• 2017

본 연구는 영업운행 중인 고속열차의 진동 문제를 고찰하고, 이를 개선하기 위하여 진행되었다. 먼저 고속열차의 진동 수준을 알기 위하여 차체 진동가속도에 대한 측정이 수행되었다. 측정결과 운전실이 객차보다 진동이 크며, 열차 후미로 갈수록 진동이 더 커졌다. 운전실 및 객차 모두 수직방향 진동이 횡방향 진동에 비해서 크며, 콘크리트 구간에 비해 자갈궤도에서 진동의 최대값이 크다. KTX-산천 진동 경향과 개선점을 도출하기 위하여 동역학 해석을 수행하였다. 해석결과는 시험 결과와 유사하였으며, 객차 양 끝단의 단부객차 상부와 동력차량의 진동을 저감시킬 필요가 있었다. 객차의 진동을 저감하기 위하여 KTX-호남(200호대) 차량은 4가지 개선 설계를 수행하였고, 이 중 KTX-산천에 적용할 수 있는 방법을 해석에 적용하였을 때, 정상구간에서는 2.2%, 분기기구간에서는 11% 정도 진동이 감소할 것으로 예상되었다. 동력차량의 진동 저감을 위해 2차 코일스프링의 강성을 감소시키고, 2차 수직댐퍼의 댐핑계수를 증가시키는 방안을 제안하였다. 현가장치의 불량, 오조립 등 성능저하가 차체 및 대차의 진동을 증가시키는 것을 시운전 결과와 해석결과를 통하여 살펴보았으며, 현가장치 올바른 유지보수가 차량 진동을 저감시킴을 알 수 있었다. 차륜 마모에 대한 적절한 관리는 운행 효율 및 차체 진동저감에 중요한 역할을 하며, 현재 차륜 프로파일을 변경하여 차륜 삭정간의 주행거리를 늘리려는 연구가 진행 중이다.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.180-187
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• 2007

This paper presents a mathematical vehicle model that is designed to analyze the dynamic performance and to develop various safety control systems. Wheel slip controllers for ABS is also formulated to improve the vehicle response and to increase the safety on slippery road. Validation of the model and controller is performed by comparison with a commercial software package, CarSim. The result shows that performances of developed vehicle model are in good accordance with those of the CarSim on various driving conditions. Developed ABS controller is applied to the vehicle model and CarSim model, and it achieves good control performance. ABS controller improves lateral stability as well as longitudinal one when a vehicle is in turning maneuver on slippery road. A driver model is also designed to control steer angle of the vehicle model. It also shows good performance because the vehicle tracks the desired lane very well.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2579-2585
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• 2009

컴퓨터시스템을 중단 없이 정상적으로 동작 시키는 것은 중요한 문제중의 하나이다. 이와 같이 컴퓨터 시스템이 중단없이 동작하도록 하기 위하여 여러 가지 고장 감내 기법들이 개발 및 상용화되어 사용되고 있다. 대부분의 고장 감내 기법은 많은 경비가 소요된다. 본 논문은 리눅스 운영체제에서 동적 모듈(DLM : Dynamic Linking Module)을 이용하여 USB 디바이스를 연결할 경우USB 디바이스 사용에 대해 발생할 수 있는 커널 PANIC 현상을 줄이는 커널 하드닝 기법을 제안한다. 제안된 기법이 제대로 동작되는지를 실험하였다. 실험 결과 DLM기능을 이용한 USB 드라이버의 동작이 정상 동작됨을 확인할 수 있었다.