• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.290-301
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• 2019

The proposed algorithm deals with a detection problem of target echo for narrow-band continuous-wave active sonar in the underwater environment in this paper. In the active sonar systems, ping signal emitted for target detection produces a signal that consists of multiple reflections by many scatterers around, which is called reverberation. The proposed algorithm aims to detect the low-Doppler target echo in the reverberant environment. The proposed algorithm estimates the bearing, frequency, and temporal bases based on beamspace-domain multichannel nonnegative matrix factorization. In particular, the bases are divided into two basis groups - the reverberation group and the echo group, then the basis groups are estimated independently. In order to evaluate the proposed algorithm, a simulation with synthesized reverberation was performed. The results show that the proposed algorithm has enhanced performance than the conventional algorithms.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.43-50
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• 2021

As the frequency of earthquakes in some regions including Pohang City has increased in recent years, the need for countermeasures against earthquakes in Korea is demanded from various aspects. Liquefaction occurred after the earthquake, and local residents' anxiety increased due to the lack of preparation for and coping with the earthquake. In order to cope with these phenomena and relieve the anxiety of local residents, we analyze the limitations of the existing earthquake response system and come up with a method to solve them. Therefore, we propose, implement, and prove the possibility of a one-stop mobile support diffusion system capable of expressing and spreading evaluation-based earthquake information that can actively cope with disaster situations.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.350-353
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• 2020

The validity of the calculation method based on the local mode in hydrogen-bonded water molecules was investigated by comparing the frequencies of the local and normal modes of OH stretching vibration in water molecules. By calculating a monomer, dimer, and trimer of water molecules using a quantum chemical ab initio theory, we examined how the frequencies of the local and normal modes and the anharmonicity of local modes vary with molecular cluster size. It was shown that, as the number of molecules increases from monomer to trimer, the anharmonicity of OH bonds increases and the difference between local and normal mode frequencies decreases. This confirms that local-mode-based calculations that can easily handle the anharmonicity can be appropriate for the calculation of the OH stretching frequency of water molecules in the condensed phase.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.161-170
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• 2008

Despite the recent growth in size and frequency of damages caused by illegal information breaches, current business counter-measures and precautionary systems are greatly limited. Some major companies have developed Information Security Management Systems (ISMS) to safeguard their vital information; however, such measures are largely based on the ISO27001 and lacks in many aspects to grasp the holistic corporate security level and reinforce precautionary measures. The information protection level evaluation model introduced in this paper is a pragmatic evaluative tool that can be utilized to devise effective corporate information security precautionary measures and countermeasures, based on the BSC (Balanced ScoreCard) method for an actual and realistic corporate information security level evaluation possible.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.35-44
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• 2002

In this paper, an implementation method of RSA exponentiator based on Radix-$2^k$ modular multiplication algorithm is presented and verified. We use Booth receding algorithm to implement Radix-$2^k$ modular multiplication and implement radix-16 modular multiplier using 2K-byte memory and CSA(carry-save adder) array - with two full adder and three half adder delays. For high speed final addition we use a reduced carry generation and propagation scheme called pseudo carry look-ahead adder. Furthermore, the optimum value of the radix is presented through the trade-off between the operating frequency and the throughput for given Silicon technology. We have verified 1,024-bit RSA processor using Altera FPGA EP2K1500E device and Samsung 0.3$\mu\textrm{m}$ technology. In case of the radix-16 modular multiplication algorithm, (n+4+1)/4 clock cycles are needed and the 1,024-bit modular exponentiation is performed in 5.38ms at 50MHz.

• Journal of Sport and Applied Science
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• v.5 no.2
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• pp.63-71
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• 2021

Purpose: The purpose of this study, we will evaluate and analyze the importance and performance of Seongnam Football Club visitors using IPA analysis to present new marketing strategies and improvement plans based on the basis of the audience's perception of the team's priority, low priority, and excessive effort. Research design, data, and methodology: In order to achieve the purpose of the study, the survey was conducted on 120 home spectators of Seongnam Football Club, and the analysis of the data was conducted using SPSS Window Version 21.0. Data were analyzed via frequency analysis, exploratory factor analysis, corresponding sample t-test, and IPA analysis. Findings are as follows. Results: First, the first quadrant showed 'The convenience of access to the stadium', 'Parking lot convenience', 'Tournament schedule guidance', 'Providing information about player', 'Providing information about the team', 'Ticket reservation method'. Second, the second quadrant showed 'Players' fan service', 'Cleanliness of toilets', 'A player's level of performance', 'Team's level of play', 'A match against a rival team'. Third, the third quadrant showed 'Indication of facility guidance', 'Seat comfort', 'Team's Star Player Possession', 'Various participation events', 'Gift recommendation'. Fourth, the fourth quadrant showed 'Player-related promotion through media', 'Promote match schedules through media', 'Entrance convenience', 'Ticket Price'. Conclusions: Based on these findings, Factor in first quadrant, fourth quadrant should be kept. On the other hand, factors in second quadrant should be improved as soon as possible while factors in third quadrant can be improved through new marketing strategies in the future. Future implications were discussed.

• Earthquakes and Structures
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• v.22 no.6
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• pp.609-623
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• 2022

To study the empirical seismic fragility of a reinforced concrete girder bridge, based on the theory of numerical analysis and probability modelling, a regression fragility method of a rapid fragility prediction model (Gaussian first-order regression probability model) considering empirical seismic damage is proposed. A total of 1,069 reinforced concrete girder bridges of 22 highways were used to verify the model, and the vulnerability function, plane, surface and curve model of reinforced concrete girder bridges (simple supported girder bridges and continuous girder bridges) considering the number of samples in multiple intensity regions were established. The new empirical seismic damage probability matrix and curve models of observation frequency and damage exceeding probability are developed in multiple intensity regions. A comparative vulnerability analysis between simple supported girder bridges and continuous girder bridges is provided. Depending on the theory of the regional mean seismic damage index matrix model, the empirical seismic damage prediction probability matrix is embedded in the multidimensional mean seismic damage index matrix model, and the regional rapid prediction matrix and curve of reinforced concrete girder bridges, simple supported girder bridges and continuous girder bridges in multiple intensity regions based on mean seismic damage index parameters are developed. The established multidimensional group bridge vulnerability model can be used to quantify and predict the fragility of bridges in multiple intensity regions and the fragility assessment of regional group reinforced concrete girder bridges in the future.

• The Journal of the Acoustical Society of Korea
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• v.40 no.2
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• pp.161-168
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• 2021

In this paper, a Silent Speech Interface (SSI) technology was proposed in which Doppler frequency shifts of the reflected signal were used to synthesize the speech signals when 40kHz ultrasonic signal was incident to speaker's mouth region. In SSI, the mapping rules from the features derived from non-speech signals to those from audible speech signals was constructed, the speech signals are synthesized from non-speech signals using the constructed mapping rules. The mapping rules were built by minimizing the overall errors between the estimated and true speech parameters in the conventional SSI methods. In the present study, the mapping rules were constructed so that the distribution of the estimated parameters is similar to that of the true parameters by using Generative Adversarial Networks (GAN). The experimental result using 60 Korean words showed that, both objectively and subjectively, the performance of the proposed method was superior to that of the conventional neural networks-based methods.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.85-97
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• 2021

In this paper, in order to support rapid and effective decision-making and response in disaster situations, we identified the author's organization of academic research papers and conducted a collaborative relationship analysis study based on this. For this purpose, 2,308 papers in 69 Korean academic journals classified by disaster and safety type were selected for analysis and experimental data were constructed based on the Korea Science Citation Database (KSCD) and institutional identification data provided by KISTI. Collaborative relationship analysis was conducted for each of the four units (Institution, Institution type, Institution region and University department type). First, statistical status such as frequency of appearance was compared, and basic properties and main centrality index of each co-occurrence network were calculated and analyzed using Social Network Analysis Method. In addition, a visualization map was created and presented for each network so that the collaborative relationship could be viewed and understood as a whole. The results of this study are expected to contribute to the search activities of institutions and cooperative groups that support effective disaster response and to lay the foundation for the information service system.

• Journal of Fashion Business
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• v.26 no.2
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• pp.15-27
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• 2022

The purpose of this study is to perform research of ecology concepts expressed in fashion and to propose a new ecology fashion design based on the results. As a specific research method, first, to determine the concept of ecology, the contents related to ecology were extracted and organized through literature research, and then a fashion collection research was conducted to acquire basic design data, such as silhouettes, materials, details, and colors. From WGSN, and a total of 57 images were selected and used as basic data for the design suggestions. As a result of collecting the collection images, it was found that cotton or denim fabrics were mainly used, and in particular, the frequency of use was high mainly for bright tones. The use of chambray, lace, and wrinkles, was also frequent, and the use of expression techniques using burn-out, bleach, and bleaching effects or parts, or entire dyeing was often noticeable. The colors showed neutral and pastel-toned characteristics, and the silhouette was mainly composed of long silhouettes centered on maxi, such as a top or calf based on the knee, rather than a mini. Fabrics for the final designs were linen and sappan wood, and they were used for the dye and red was used as the overall color. The silhouettes were simplified, and care was taken to prevent unnecessary waste, such as paper or materials, from being generated during the production stage. We tried to achieve the purpose of eco-logy by refraining from excessive trimming, except for essential subsidiary materials, such as zippers.