• Transactions of the KSME C: Technology and Education
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• v.5 no.2
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• pp.115-126
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• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1018-1024
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• 2011

For the driving of the sinusoidal type permanent magnet synchronous motor with a maximum continuous torque, the 1200 delayed three phase sinusoidal current inputs which matched with the absolute rotor position are needed at the stator coil. Therefore, the detection of a absolute rotor position is required inevitably. And the right angle relationship between stator magnetic field and rotor magnetic field has to be preserved at a stator by this commutation action. The detection of a absolute position for the commutation can be made generally by the output signal analysis of the encoder attached at a motor shaft. The purposes of this study are to design signal processing logic circuits which could detect the absolute position of motor with a modern encoder system and generate the three reference wave for making sinusoidal current input at a stator coil.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.8-15
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• 2007

Freeway corridors consist of urban freeways and parallel arterials that drivers can use alternatively. Ramp metering in freeways and signal control in arterials are contemporary traffic control methods that have been developed and applied in order to improve traffic conditions of freeway corridors. However, most of the existing studies have focused on either optimal ramp metering in freeways, or progression signal strategies between arterial intersections. There have been no traffic control systems in Korea that integrates the freeway ramp metering and arterial signal control. The effective control strategies for freeway operations may cause negative effects on arterial traffic. On the other hand, traffic congestion and bottleneck phenomenon of arterials due to the increasing peak-hour travel demand and ineffective signal operation may generate an accessibility problem to freeway ramps. Thus, the main function of the freeway which is the through-traffic process has not been successful. The purpose of this study is to develop an integrated control model that connects freeway ramp metering systems and signal control systems in arterial intersections. And Optimization of integrated control model which consists of ramp metering and signal control is another purpose. The design of experiment, neural network, and simulated annealing are used for optimization.

• Journal of the Society of Disaster Information
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• v.9 no.2
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• pp.188-194
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• 2013

As the high speed railroad line increases, researches on developing a more economic high speed railroad bridge system have been actively conducted. In this paper, a new type of prestressed concrete girder based on the bi-prestressing technique, which can introduce additional prestress, is presented. The additional prestress can be introduced using a wedge-shaped pin bar into the upper part of the girder section. The applicability of the new girder technique to the high speed railroad bridge is verified via the dynamic stability analysis. Dynamic moving load analyses using the KTX train load are conducted on bridge systems with the span lengths of 30m, 35m, and 40m, respectively. The results of the analysis show that all bridge systems satisfy the limits prescribed in the design specifications to ensure structural stability, driving safety, and ride quality.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.135-140
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• 2019

In this paper, a frequency split type broadband drive amplifier operating in the L, S and C bands was designed and fabricated. Transistor is difficult to efficiently use when the fractional bandwidth of the drive amplifier is more than 100%, In particular, the characteristics of the driving amplifier are important for operating the power amplifier in which the characteristics of the output power and the efficiency are sensitively changed according to the frequency band. A frequency split methods was applied to maximize the bandwidth of a drive amplifier and to divide the output of the drive amplifier into low band and high band so that the transistor of the power amplifier located at the rear of the drive amplifier can be efficiently used. The designed drive amplifier was fabricated in GaAs HBT technology and 9-layer SiP, and verified by the measurements. The fabricated drive amplifier shows a gain of more than 8 dB and an output power of more than 15 dBm in the operating frequency range.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.221-223
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• 2016

Currently in the automobile market, models with many convenient functions combined with IT have been released. This change has a strength that there could be many convenient and useful functions related to driving while flaws of vehicles caused by malfunctions of these electronic equipments could trigger serious incidents. Among them, the sudden unintended acceleration considered as the most serious is a serious flaw that could threaten driver's life. However, the causes for sudden acceleration incidents have not been clearly investigated with no coping measures. As manufacturers shift the responsibility to drivers' carelessness, drivers' burden is continuously increasing. Thus, this paper designed the system to cope with sudden acceleration incidents by changing conditions of controlling parts like accelerator and brake, and internal image of the driver's seat into data through the integrated module.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.1
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• pp.75-80
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• 2021

Positioning technology is performing important functions in augmented reality, smart factory, and autonomous driving. Among the positioning techniques, the positioning method using beacons has been considered a challenging task due to the deviation of the RSSI value. In this study, the position of a moving object is predicted by training a neural network that takes the RSSI value of the receiver as an input and the distance as the target value. To do this, the measured distance versus RSSI was collected. A neural network was introduced to create synthetic data from the collected actual data. Based on this neural network, the RSSI value versus distance was predicted. The real value of RSSI was obtained as a neural network for generating synthetic data, and based on this value, the coordinates of the object were estimated by learning a neural network that tracks the location of a terminal in a virtual environment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.40-46
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• 2021

An automatic transmission of automobiles enables comfortable driving experience with lower transmission shifting jerks. However, the assembly structure is more complicated and requires additional components with lower efficiency than the manual transmission system. Extensive research has been conducted to improve the overall transmission efficiency by optimizing each component of the automatic transmission assembly. This study focuses on enhancing the friction torque of double angular contact ball bearings used in automatic transmission. The friction torque of the bearing varies with the operating conditions such as the operational load and rotating speed. Since reducing the friction torque of the bearing tends to deteriorate the durability of the bearing, it is necessary to design the bearing having a minimum required friction torque by determining the durability life of an automatic transmission assembly, In this study, the theoretical life and friction torque of conventional and newly-developed bearings are calculated. The difference in the friction torque between the new and existing bearings are also evaluated.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.266-283
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• 2022

With the rapid development of autonomous vehicle technology, unexpected accidents are occurring. Therefore, it is necessary to minimize user accident damage through the development of autonomous traffic safety education. Since edge cases, accident type, and risk factor analysis are important for realistic education, overseas case studies and demonstrations were carried out, and based on this, two curriculum for service providers and general users were developed. The service provider curriculum consisted of OEDR, sudden stop, cut-in, take-over, defensive driving, system malfunction, policy and information security education, and the general user curriculum consisted of attention duty, take-over, operating design domain, accidents type, laws, functions, information security education.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.371-374
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• 2021

자율주행 기술이 급속도로 발전하고 있지만, 자율주행 레이싱 기술과 관련 산업은 전세계적으로 아직 걸음마 수준이다. 본 연구팀은 국내 자율주행차 대표기업인 (주)언맨드솔루션에서 지원하는 플랫폼을 사용하여 자율주행 레이싱 제어 모델 프레임워크를 설계하고 기초 실험을 진행하였다. 제안된 자율주행 레이싱 제어 모델은 GPS 신호처리부, LiDAR 신호처리부, 영상처리부, 차량제어부, 추월/회피 제어부, 컨트롤러 통신부 등으로 구성된다. 실험을 통해 각 구성요소에 대한 기본 성능을 검증하였고, 레이싱에 최적화된 인공지능(AI) 기반 추월/회피 제어 알고리즘 개발을 위한 중요한 토대를 마련하였다. 본 연구를 바탕으로 2021년 11월에 국내 최초로 개최되는 세계 AI 로보카레이스 대회에 출전하여 제안된 자율주행 레이싱 제어 모델 프레임워크의 성능을 검증할 계획이다.