• The Journal of Bigdata
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• v.2 no.2
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• pp.129-140
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• 2017

Weather acts through low visibility, precipitation, high winds, and temperature extremes to affect driver capabilities, vehicle performance (i.e., traction, stability and maneuverability), pavement friction, roadway infrastructure, crash risk, traffic flow, and agency productivity. Recently a variety of road weather big data sources such as CCTV, road sensor/systems, car sensor have been developed to solve the weather-related problems, This study identifies and defines the types and characteristics of these sources to suggest how to utilize them for car safety and efficiency as well as road management through analyzing domestic and oversea cases of road weather big data applications.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.3
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• pp.17-25
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• 1999

This paper proposes a new bit-serial multiplier/divider architecture to reduce the hardware complexity significantly and to maintain the same number of cycles compared with existing architectures. Since the proposed bit-serial multiplier/divider architecture does not extend the number of bits in registers and an adde $r_tractor to calculate a partial product or a partial remainder, the hardware overhead can be greatly reduced. In addition, the proposed architecture can perform an additio $n_traction and a shift operation in parallel and the number of cycles for $\textit{N}$-bit multiplication and division for the proposed circuits is $\textit{N}$ and $\textit{N}$ + 2, repectively. Thus, the number of cycles for multiplication and division is the same compared with existing architectures. The SliM Image Processor employs the proposed multiplier/divider architecture and proves the performance of the proposed architecture.cture.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.204-209
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• 1998

The acceleration of the performance of machine tools influences the development of the semi-conductor and optical technology as the development of NC and measurement technology. We can mention that a traction role of the acceleration for the development like that depends on the development of the measurement technics Stylus instrument method, STM, SEM, Laser interferometer method which are used for measuring the quasi-static error of machine tools. Because the measurement has been done to unload condition without considering of mechanical stiffness in the case of machining center as we measure the quasi-static error of machine tools on general studies, people who works on the spot has many problems on the data value. Therefor we will help working more accurately on the spot by measuring, analyzing, displaying the deflection of the table and support shaft when we load on the table and the support shaft of machining center using laser interferometer. Also we try to settle new conception of the measurement method and more accurate grasp of the deflection tendency by verifing the tendency of the error measured through the comparison of the simulated error using ANSYS, a common finite element analysis program, which is able to measure heat deformation, material deformation, and error resulted form this study.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.3
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• pp.368-386
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• 1994

The primary purpose of this study was to identify the diversity and embellishment of American Indian clothing and relationship between culture and clothing in American Indian Culture Areas. After the introduction of European material culture, change in American Indian clothing was conducted. The result of the Study as follows: 1. The most influential factors affecting the diversity of American Indian clothing were environmental factors. Climates and geographical features, Raw material were reflected in clothing style and clothing material in each culture Area. 2. Economic situation and life style were shown to be influential to clothing development. The best known instance of this was greatly elaborated clothing and personal adornment of the Plains who had higher stand of life and nomadic life style. 3. Religious concepts were important factors influencing American Indian clothing. Indian tribes had different ritual performance they used particular motifs in clothing. Clothing, such as "ghost shirt", Apache medicine shirt and Pueblo ceremonial clothing, served hidden pur- poses. 4. Techenology was another factor identified in this study as influencing American Indian clothing. Especially, weaving skills of Southwest played a great role in textile development. Pueblo "manta" and Navaho "bil" were famous for Indian costume. 5. European material culture allowed great change of traditional native Indian clothing. American Indian had new material, new styles, new concept of clothing. 6. American Indian, although Indian applicated European trade goods, was actually quite conservative in retaining traditional designs and modes of decoration. Asthetics and traction of American Indian were reflected in American Indian clothing.d in American Indian clothing.

• Earthquakes and Structures
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• v.11 no.5
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• pp.841-859
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• 2016

Bridge bearings are important connection elements between bridge superstructures and substructures, whose health states directly affect the performance of the bridges. This paper systematacially presents a new method to identify the bridge bearing damage based on the neural network theory. Firstly, based on the analysis of different damage types, a description of the bearing damage is introduced, and a uniform description for all the damage types is given. Then, the feasibility and sensitivity of identifying the bearing damage with bridge vibration modes are investigated. After that, a Radial Basis Function Neural Network (RBFNN) is built, whose input and output are the beam modal information and the damage information, respectively. Finally, trained by plenty of data samples formed by the numerical method, the network is employed to identify the bearing damage. Results show that the bridge bearing damage can be clearly reflected by the modal information of the bridge beam, which validates the effectiveness of the proposed method.

• 연구논문집
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• s.26
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• pp.5-14
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• 1996

Test results of electromagnetic suspension (EMS) type urban transit maglev system are reported. Electromagnetic levitation system is a transportation system taking advantage of the attraction of normal conducting electromagnets to support and guide the train in combination with the linear induction traction motors. Urban Transit Maglev (UTM) Which is being developed by the maglev team in KIMM and the Hyundai Precision Company since 1995 consists of three bogies. In the first year, two types of Bogies are developed. Bogie I uses an analog controller for levitation and guidance control and is driven by two linear induction motors (LIM) mounted on the right and left side of module. Bogie II uses a digital controller and is driven by one LIM mounted along the center line of the bogie. Test results reported in this paper are those obtained with Bogie II with a digital controller. Also included in this paper is a brief explanation of the electromagnetic suspension levitation system which is being developed by the maglev team in KIMM.

• Journal of Power Electronics
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• v.16 no.2
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• pp.542-552
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• 2016

Central 60° synchronous modulation is an easy pulse-width modulation (PWM) method to implement for the traction inverters of urban rail trains at a very low switching frequency. Unfortunately, its switching patterns are determined by a Fourier analysis of assumed steady-state voltages. As a result, its transient responses are not very good with over-currents and high instantaneous torque pulses. In the proposed solution, the switching patterns of the conventional central 60° modulation are modified according to the dynamic error between the target and actual stator flux. Then, the specific trajectory of the stator flux and current vector can be guaranteed, which leads to better system transients. In addition, stator flux control is introduced to get smooth mode switching between the central 60° modulation and the other PWMs in this paper. A detailed flow chart of the control signal transmission is given. The target flux is obtained by an integral of the target voltage. The actual PMSM flux is estimated by a minimum order flux state observer based on the extended flux model. Based on a two-level inverter model, improved rules in the α-β stationary coordinate system and equations of the switching patterns amendment are proposed. The proposed method is verified by simulation and experimental results.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.125-133
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• 2011

The wear of rubber track being in contact with the road surface is an important subject because it decreases the traction performance and the operating efficiency of tracked vehicle. For the above reasons, many attempts have been made to quantitatively calculate the rubber track. However, it depends on the experimental methods which are highly time- and cost-consuming. Therefore, the numerical simulation approach is highly desirable, but it needs to model the complex geometry and the material behavior in details as well as the interaction with the road surface. In this study, the rubber track and its material behavior are elaborately modeled since these factors are very important in the prediction of the wear rate of the rubber track. Accordingly to the studies on the rubber wear by previous investigations, it has been found that the wear is greatly influenced by the frictional energy. The frictional energy of rubber track is computed by utilizing the 3D finite element analysis of the rubber track, and the wear rate is evaluated making use of the frictional energy and a wear model.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1209-1212
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• 2008

The high-speed EMU is assembled with distributed EMI sources. Therefore, it contains more electromagnetic sources nearby the distributed victims than the existing concentrated traction system. The electromagnetic sources and victims are identified in this research, and the methodology how to handle EMI/EMS/EMC of the high-speed EMU will be developed for safer operation. It includes measurement method, safety standards of control units and others, and performance evaluations of the firstly developed trial products for the EMU. Also influences by modern telecommunication equipments and effect of PLD(power line disturbance) are to be surveyed in this research.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.7
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• pp.500-508
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• 2000

Basic design for single-phase active power filter, which aims at railway application provided with PWM-controlled converters, is comprehensively studied and its performance is presented in this paper. Active power filters are used to compensate railway signaling and public telecommunication interference due to the high-order harmonic currents generated in railway traction locomotives. A type of hybrid digital filter which is composed of low pass filter and high pass filter is proposed so that the desired harmonic reference current with accurate magnitude and phase shift can be extracted from catenary line current. A design criteria to determine input inductor L and output capacitor C is also described, considering voltage, current, PWM pattern, and switching frequency of the main converters. Finally, computer simulation and DSP-based experiments resulted from laboratory test are presented.