• KOREAN POULTRY JOURNAL
• /
• v.54 no.4
• /
• pp.116-120
• /
• 2022

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.28 no.1
• /
• pp.63-69
• /
• 2015

In this paper, infrared reflector design targeting infrared stealth effect is presented using structural optimization based on the phase field method. The analysis model was determined to accomplish the design that an incident infrared wave was reflected to a desired direction. The design process was to maximize the objective value at the measuring domain located in a target region and the design objective was set to the Poynting vector value which represents the energy flux. Optimization results were obtained according to the variation of some parameter values related to the phase field method. The model with a maximum objective value was selected as the final optimal model. The optimal model was modified to eliminate the gray scale using the cut-off method and it confirmed improved performance. In addition, to check the desired effect in the middle wave infrared range(MWIR), the analysis was performed by changing the input wavelength. The finite element analysis and optimization process were performed by using the commercial package COMSOL combined with the Matlab programming.

• Journal of Digital Convergence
• /
• v.16 no.9
• /
• pp.489-495
• /
• 2018

The purpose of this study was to investigate the effect of fouls on performance in field hockey games. A total of 33 matches and 2101 fouls from 10 teams participated in the 2017 World League SEMI-FINAL tournament were analysed by region, race, type, and cause. The total data that is analysed by SportsCode and SPSS(correlation analysis & chi-square test)have showed that the top ranked countries had a higher foul frequency than the lower ranked nations. According to the situation that has showed the result of the analysis, it showed that there was no difference between the results analysed on the foul type and the attacking and defence situation but it has indicated that area, game situation and the cause of fouls showed there was a significant difference. On these results, it is hoped to use fouls as one of the tactical means in women's field hockey games.

• Journal of Digital Convergence
• /
• v.18 no.6
• /
• pp.495-500
• /
• 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
• /
• v.53 no.7
• /
• pp.11-16
• /
• 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.

• Journal of the Korea Convergence Society
• /
• v.6 no.4
• /
• pp.47-54
• /
• 2015

This study was conducted an convergence research on 210 mothers in order to examine the effect of golf on subjective happiness of mothers who have children with disabilities. The factors were conducted surveys using SPSS WIN 18.0 program. Firstly, were mostly 40s, college graduates, Buddhists or had no religion, had housekeeping as occupation, had average household income, and most of them were healthy. In addition, descriptive statistics on their years of experience in golf, golf strokes, field, practice frequency, and practice hours were all above average. Secondly, significant correlations were suggested between experience in golf, golf strokes, field, practice frequency, silence during practice hours, and in the subjective happiness of negative correlation as a result of analysing the correlations between the factors. Thirdly, the field, practice frequency, and practice hours affected the subjective happiness.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.11 no.1
• /
• pp.1-11
• /
• 2018

This paper provides field test results to confirm and compare the receiving characteristics of digital radio in various environments. HD Radio and DRM+ was used for the in-band method, while DAB/DAB+/T-DMB were used for the out-of-band method. To run field tests for digital radio, a transceiver test bed was constructed in a region in Korea selected as suitable for the testing, and indoor and outdoor reception tests were conducted by selecting 16 test points with different levels of multipath. Not only was the receivability tested at the test point, but ATT margin was also applied, in order to derive the minimum reception level. Through various analyses, the findings obtained through the field tests can aid in the setting of a standard for determining the method of digital radio transmission to ensure a smooth reception environment for consumers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.05a
• /
• pp.704-711
• /
• 2003

Recently, the demands for real-time service and multimedia data are rapidly increasing. There are significant redundancies between header fields both within the same packet header and in consecutive packets belonging to the same packet stream. But there are many overheads in using the current UDP/IP protocol. Header compression is considered to enhance the transmission efficiency for small size of payload. By sending the static field information only once initially and by utilizing dependencies and predictability for other fields, the header size can be significantly reduced for most packets. This work describes an implementation for header compression of the headers of U/UDP protocols to reduce overhead on Ethernet network. Typical UDP/IP Header packets can be compressed down to 7 bytes and the header compression system is designed and implemented on the Linux environment. Using the designed Header compression system between a server and a client have the advantage of effective data throughput in network.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.9
• /
• pp.973-978
• /
• 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
• /
• v.11 no.2 s.31
• /
• pp.242-253
• /
• 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.