• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.111-122
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• 2012

There has been a strong demand for providing diverse services to drivers utilizing existing ITS infrastructure. To this end, this study is aiming at improving the accuracy of a variable speed limit system by determining recommended speeds for the system utilizing the information from Urban Traffic Information System(UTIS) and Weather Information System(WIS). In order to determine appropriate speed limits under inclement weather conditions for the variable speed limit system, this study examined three methods: i) the method utilizing the information from WIS, ii) the method utilizing the information from UTIS, and iii) the method which combines the information from WIS and UTIS using different weights for diverse weather conditions. Finally, this study selected the third method which determines an appropriate speed limit using the relationship between the vehicle operating speed and the minimum stopping distance which is estimated using the existing speed limit, surface coefficient of friction and superelevation.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2065-2069
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• 2004

This paper presents an adaptive equalizer using finite impulse response (FIR) filter and least-mean square (LMS) algorithm. Herein, the variable step-size technique (VSLMS) for compensating the amplitude of chrominance signal is utilized. The proposed equalizer can be enhanced and compressed the chrominance signal at color subcarrier. The LMS algorithm employed in simplicity structure but gives slow convergence speed. Thus, the variable step-size is very attractive algorithm due to its computational efficiencies and the speed of convergence is improved. In addition, experimental results are carried out by using the modulated 20T sine squared test signal. It is shown here that the adaptive equalizer can be equalized the amplitude chrominance distortion in color television transmission without relative delay distortion.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.325-339
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• 2018

In this paper, we propose a joint adaptive combining and variable tap-length multiuser detector (MUD) for amplify-and-forward (AF) underwater acoustic cooperative interleave-division multiple access (IDMA) communication system. The proposed MUD jointly realizes tap-length adjustment, adaptive combining, and multiuser detection. In contrast to the existing methods, the proposed detector can adaptively combine the received signals from different nodes at destination, and does not need the assumption that full and perfect channel state information (CSI) of all the links at the receiver is known. Moreover, the proposed detector can adaptively adjust the tap coefficient vector and tap-length of each branch according to the specific channel profile of each branch. Simulation results validate the feasibility and show the advantages of the proposed detector against existing counterparts.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.361-362
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• 2007

This paper presents the Traffic information system that based on an embedded WinCE board which has GPS and HSDPA. This system is able to overcome the limit of area using the Internet service which other systems can't provide. When the embedded board receives data about the geometric and vehicle speed information, it transmits to the server via HSDPA/the Internet. The server receives and processes it for the path services. And also we present the path guidance algorithm which is based on the speed information. These algorithm responses to the dynamical traffic condition through updating traffic information. Especially, we suggest a Traffic Status Variable in each branch which represents each road's traffic status. This Traffic Status Variable contains speed, road grade; we separate the road three groups as speed limitation; and past speed data - for example, week day rush hour of each road. In addition, the data of cross about left-turn or right-turn can update. Those elements is consisted Traffic Status Variable.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.135-146
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• 2021

VMP(Variable Message Protocol) is bit-based variable message processing protocol that enables the sharing situation information in real time as a tactical datalink protocol for Korean Army. System A is currently under development and will be operated as an army system when its development is completed. In system A, the VMP processing terminal is mounted and the VMP is utilized for exchanging tactical information. System A can acquire situation information from mounted situation information acquisition system and share situation information with other system A by the VMP. In this paper, we propose a method of sharing situation information with system A and speed improvement methods of sharing situation information using VMP. As speed improvement methods of sharing situation information, this paper studied 'Removing Process of Sending VMP Observation Report', 'Adopting One-time Situation Information Send Button When Sharing A System Situation Information By VMP', 'Combination of Many VMP Messages Using Repeat Function Of Application Header'. And we conducted the experiment, the result was that the transmission speed of equipment to which the research method was applied was improved by 76.8% compared to the existing equipment.

• Journal of the Korean Home Economics Association
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• v.51 no.2
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• pp.195-206
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• 2013

This study was conducted in order to investigate the variables that relate and affect the internalizing and externalizing problems of multicultural children. 159 multicultural children in the $3^{rd}{\sim}6^{th}$grade were selected from elementary schools in Gwangju and the Jeollanamdo area. The data was analyzed by using the frequency, Cronbach's ${\alpha}$, t-test, ANOVA, Pearson's correlation and hierarchical regression by SPSS 12.0 program. The results were as follows: first, the internalizing problems were different according to the socio-demographic variable: (gender, subjective economic level), multicultural characteristic variable: (mother's communication ability, likability of mother's nationality, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Further, the externalizing problems were different according to the socio-demographic variable: (gender), multicultural characteristic variable: (mother's nationality, mother's communication ability, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Second, the influential variables regarding the internalizing problems were children's stress from cultural adaptability and the likability of the mother's nationality of the multicultural characteristic variable group, peer support of the social support variable group and the subjective economic-level of the socio-demographic variable group. Moreover, the influential variable on the externalizing problems was children's stress from the cultural adaptability of the multicultural characteristic variable group. The most influential variable of such variables was children's stress from cultural adaptability of the multicultural characteristic variable group. The results of this study will provide information for the development of educational and therapeutic intervention program for multicultural children.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.649-653
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• 2014

Although many reliability analysis and reliability-based design optimization (RBDO) methods have been developed to estimate system reliability, many studies assume the uncertainty of the design variable to be constant. In practice, because uncertainty varies with the design variable's value, this assumption results in inaccurate conclusions about the reliability of the optimum design. Therefore, uncertainty should be considered variable in RBDO. In this paper, we propose an RBDO method considering variable uncertainty. Variable uncertainty can modify uncertainty for each design point, resulting in accurate reliability estimation. Finally, a notable optimum design is obtained using the proposed method with variable uncertainty. A mathematical example and an engine cradle design are illustrated to verify the proposed method.

• Journal of Drive and Control
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• v.15 no.2
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• pp.9-21
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• 2018

The aim of this study was to develop and test a model of an auto-sensing hydraulic breaker that can automatically change its 4-step impact mode according to the rock strength using SimulationX. The auto-sensing hydraulic breaker with a 4-step variable impact mode has the advantage of obtaining optimal impact energy and impact frequency under various rock conditions compared to an auto-sensing hydraulic breaker with a 2-step variable impact mode, which has already been developed overseas. Several steps were necessary to conduct this study. First, the operation principle of the auto-sensing hydraulic breaker with the 2-step variable impact mode was analyzed. Based on the findings, an analysis model of the auto-sensing hydraulic breaker with the 4-step variable impact mode was developed (and compared with the 2-step variable impact mode) Finally, an analysis of the results established that the stepwise variable of the impact mode was implemented according to the rock strength and the difference of each impact mode was confirmed. This study is expected to contribute to the development of auto-sensing hydraulic breakers that are superior to those developed by advanced companies in foreign countries.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.197-213
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• 2008

This study is for the quality factors of University Information Systems (UIS) that affect students' satisfaction level. We used the quality factors as an independent variable, information systems' satisfaction level as a parameter variable, and students' satisfaction toward a university as a dependent variable. User characteristics, such as region, grade, major, and gender, were used to investigate to see if these demographic variables make mediating effects in the model. We also present an implication for better way to operate or build a university information systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.245-251
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• 2017

The proposed variable pawer divider in this paper is composed of one equal power 2-way Wilkinson power divider, two variable phase shifters with 90-degree phase variation to be connected two output paths of the 2-way power divider, and one branchline coupler to combine output signals of two variable phase shifter. The proposed variable power divider can theoretically have an arbitrary power division ratio ranging from ${\infty}:1$ to ${\infty}:1$ due to 90-degrees phase variation of two phase shifter. The proposed power divider circuit fabricates on laminated TLX-9(h=20 mil, er=2.5; Taconic) with a center frequency of 1.7 GHz. The power division ratio of the fabricated prototype varies from about 1:100 to 200:1, with an input reflection characteristic(S11) of below -16 dB, an insertion loss of about -1.0 dB, and an isolation characteristic of below -17 dB between two output ports in the range 1.65-1.75 GHz.