• Journal of Digital Convergence
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• v.18 no.6
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• pp.495-500
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• 2020

This study was intended to quantify the acceleration and deceleration information measured in the competition by using GPS device for the national women's field hockey players and to identify the difference in movement by classifying them by position. For this study, 308 acceleration and deceleration data were collected from 16 women's field hockey players measured at international competitions. According to research results, the frequency of acceleration was in the order of midfield > defender > striker, acceleration distance was midfield > striker > defender. The frequency of deceleration appeared in the order of midfield > defender > striker, deceleration distance was defender > striker > defender. Based on the results of this study, can be used as basic data when setting the strength and amount of training for field hockey players.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.11-16
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• 2016

Silicon carbide (SiC) has received significant attention over the past decade because of its high-voltage, high-frequency and high-thermal reliability in devices compared to silicon. Especially, a SiC Schottky barrier diode (SBD) is most often used in low-voltage switching and low on-resistance power applications. However, electric field crowding at the contact edge of SBDs induces early breakdown and limits their performance. To overcome this problem, several edge termination techniques have been proposed. This paper proposes an improvement in the breakdown voltage using a double-field-plate structure in SiC SBDs, and we design, simulate, fabricate, and characterize the proposed structure. The measurement results of the proposed structure, demonstrate that the breakdown voltage can be improved by 38% while maintaining its forward characteristics without any change in the size of the anode contact junction region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.973-978
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• 2014

This study focused on the design of the reflecting layer of a light trapping system fora thin film solar cell using topology optimization based on the phase field method. Therefore, incident light was caused to propagate in the desired direction by reflecting it from this layer, which is the design domain. The same method was applied to the conceptual design of an infrared stealth structure in near infrared range. The results using the phase field method were compared with those using the density method. The design objective was to maximize the Poynting vector value representing the energy flux, which was measured in a measuring domain to control the reflected wave direction. A finite element analysis and optimization process were performed using the commercial package COMSOL combined with the MATLAB programming.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.242-253
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• 2006

This paper presents and analyzes field test results of E-VSB(Enhanced-VSB) system proposed by Zenith/ATl and adopted ATSC standard. In the field test, according to types of antennas we measured reception possibility, noise margin, ease of reception to analyze performance improvement of E-VSB system at each outdoor/indoor test point. Also, we verify a backward compatibility between E-VSB and conventional 8-VSB system and check selection of test point, and configuration of transmitter and test vehicle. By the field test results, E-VSB system did not only outperform over 8-VSB system at severe multipath environment such as indoor reception, but also verified backward compatibility with it.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.372-384
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• 2014

DTV field tests have been performed to measure field strength and to check reception ratio on indoor and outdoor sites. They use an antenna of 9m to measure DTV signal in case of outdoor measurement on the road. Modern skyscrapers require the analysis of vertical-directional wave propagation by measuring vertical-directional DTV signal. Even if the field strength is above the reception threshold of $43dB{\mu}V/m$, the reception is impossible in case of strong multi-path or high impulse noise. So, vertical-directional field measurement is essential in environment of tall buildings. In this paper, we developed an octo type multi-copter to measure vertical-directional DTV signal level. A compact and portable DTV signal level meter, an antenna, a microwave transmitter for data transmission, and a recording equipment are equipped in the multi-copter. Three different sites are selected to test the measurement system. Developed measurement system using the multi-copter is very useful in measuring vertical-directional DTV signal, especially in apartments, non-accessible area by vehicles, and forbidden areas.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.977-985
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• 2011

Airborne separation assurance is a key requirement for Free Flight Airspace operations, This paper study the feasibility of airborne separation assurance for free flight Airspaces operations by evaluating the efficiency measurement models. Three qualitatively different methods are utilized; one based Ground and Air conflict probability model, other based Dynamic Density model. the other based Direct operating cost model. The evaluation is Direct Operating Cost model and Two metrics are utilized for the efficiency measurements; airborne separation assurance performed quite well in the Free Flight evaluation; (1) 2 scenario of the conflict situations are resolved; (2) The MD-80 flight peformed separation assurance and efficiency, Not only appling for geometric method algorithm is more efficiently than potential method, but also the most efficiently geometric combined method.

• Journal of the Korean Data and Information Science Society
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• v.20 no.4
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• pp.661-672
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• 2009

This study was conducted to investigate whether mat exercise and field exercise have effectiveness on the balance and gait in older adults. Thirty subjects were participated in this study. And they were all randomly divided into mat exercise and field exercise group. To evaluate the effects of mat and field exercise, subjects were evaluated by using One Leg Stand test which was static balance test, and Berg Balance test which was dynamic balance test. Finally Gait pattern was assessed by using 3-dimensional gait analysis system. The assessment parameters were evaluated before, after 3 weeks, and after 6 weeks treatments. And we received a consent form from all subjects. The results of repeated measures analysis of variance showed that One Leg Stand, Berg Balance, Stride length, Cadence, Velocity were significantly increased after than before exercise in both groups. So we conclude that therapeutic exercise that is mat and field exercise has effectiveness on the balance and gait in older adults.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.89-94
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• 2020

The purpose of this study was to investigate the correlation between visual analogue scale(VAS) of the waist and Oswestry Disability Index(ODI) and the muscle strength of the waist for male field hockey athletes. The VAS and ODI were conducted by self-written evaluation, and muscle strength was measured by using DAVID. Pearson correlation was used for data analysis, and the statistical significance level was set to α = .05. The VAS of the waist of male field hockey athletes and the ODI were statistically significant. However, other VAS and the ODI did not correlate to the strength of the lower back. Therefore, there is a need to develop a new exercise program for the rather than strength training during the waist rehabilitation exercise. It is thought that these studies will serve as basic data useful for the development of treatment and exercise programs for athletes in the future.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.672-684
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• 2020

Restoring a low resolution and motion blurred light field has become essential due to the growing works on parallax-based image processing. These tasks are known as light-field enhancement process. Unfortunately, only a few state-of-the-art methods are introduced to solve the multiple problems jointly. In this work, we design a framework that jointly solves light field spatial super-resolution and motion deblurring tasks. Particularly, we generate a straight-forward neural network that is trained under low-resolution and 6-degree-of-freedom (6-DOF) motion-blurred light field dataset. Furthermore, we propose the strategy of local region optimization on the adversarial network to boost the performance. We evaluate our method through both quantitative and qualitative measurements and exhibit superior performance compared to the state-of-the-art methods.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.280-282
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• 2003

본 연구에서는 HFC망에서 음성 통화품질에 영향을 주는 파라미터들에 대한 분석과 측정을 통해 VoIP의 특성을 파악하여 향후 본격적으로 이루어질 인터넷을 통한 음성 서비스 제공에 대비하였다 특히, VoIP QoS 기준의 정의는 QoS 파라미터의 분석을 토대로 한 lab 테스트와 HFC VoIP 서비스의 필드 측정을 병행하여 연구 결과에 대한 실질적 서비스 적용에 따르는 신뢰성을 높였다.