• 한국자기학회지
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• 제5권5호
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• pp.548-551
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• 1995

The effect of Cu substitution on the properties of NiZn ferrites sintered at low temperature with composition is investigated. The densification of NiCuZn ferrite in dependent upon Cu content in the composition of (N/sub 0.5-x/Cu/sub x/ Zn/sub 0.5/O)(Fe/sub 2/O/sub 3/)/sub 0.98/. Electrical resistivity is maximum at x=0.2. Dispersion characteristics of complex permeability of (Ni/sub 0.5-x/ Cu/sub x/Zn/sub 0.5/O)(Fe/sub 2/O/sub 3)/sub 0.98/ is observed above x=0.3 and relaxation frequency increases with higher temperature. The magnetic loss of NiCuZn ferrite is occurred above the Cu content x=0.3 at a low frequency.

• International Journal of Internet, Broadcasting and Communication
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• 제14권4호
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• pp.52-57
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• 2022

In this study, keywords from representative online portal sites such as Naver, Google, and Youtube were collected based on text mining analysis technique using Textom to check the changes in metqaverse after COVID-19. before Corona, it was confirmed that social media platforms such as Kakao Talk, Facebook, and Twitter were mentioned, and among the four metaverse, consumer awareness was still concentrated in the field of life logging. However, after Corona, keywords from Roblox, Fortnite, and Geppetto appeared, and keywords such as Universe, Space, Meta, and the world appeared, so Metaverse was recognized as a virtual world. As a result, it was confirmed that consumer perception changed from the life logging of Metaverse to the mirror world. Third, keywords such as cryptocurrency, cryptocurrency, coin, and exchange appeared before Corona, and the word frequency ranking for blockchain, which is an underlying technology, was high, but after Corona, the word frequency ranking fell significantly as mentioned above.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.213-217
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• 2002

Recently the subject of "wavelet analysis" has be drawn by both mathematical and engineering application fields such as Signal Processing, Compression/Decomposition, Wavelet-Neural Network, Statistics and etc. Even though its similar to courier analysis, wavelet is a versatile tool with much mathematical content and great potential for applications. Especially, wavelet transform uses localizable various mother wavelet functions in time-frequency domain. Therefore, wavelet transform has good time-analysis ability for high frequency component, and has good frequency-analysis ability for low frequency component. Using the discriminative ability is more easy method than other conventional techniques. In this paper, Morlet wavelet transform was applied to discriminate the kind of line fault by acquired data from real power transformation network. The experimental result presented that Morlet wavelet transform is easier, and more useful method than the FFW (Fast courier Transform).ransform).

• 한국인터넷방송통신학회논문지
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• 제11권2호
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• pp.189-196
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• 2011

디지털 콘텐츠는 IT 산업의 핵심적인 콘텐츠로 인터넷의 발전과 더불어 다양한 분야에서 개발되고 있다. 사용자의 멀티미디어 장비가 다양해지고 성능이 향상되어 감에 따라 디지털 콘텐츠 보호는 더욱 복잡해지고 다양한 보호 시스템 개발을 요구한다. DRM(Digital Rghts Management)은 대표적인 콘텐츠 보호 시스템이며 이 기술 기반으로 다양한 콘텐츠 보호 기법이 등장하고 있다. 그러나 콘텐츠와 배포형태에 따른 다수의 기술을 적용해야하는 문제점과 "analog hole" 문제 및 키 분배 방식의 비효율성으로 인해 안전하게 보호하기 어렵다. 본 논문에서는 이러한 문제점을 해결하기 위해서 RFID(Radio Frequency Identification) 기술을 이용한 콘텐츠의 인증 및 보호 시스템 제안하고 스마트 홈 환경에서 자유로운 콘텐츠의 복제 및 효율적인 콘텐츠관리가 가능함을 보인다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.389-394
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• 2005

In this study we carried out to evaluate the salinity concentration and volumetric water content of unsaturated soil column using frequency domain Reflectometry with vector network analyzer (FDR-V) measurement system. All of experiments were considered to the effect of temperature which ranges from l0$^{\circ}C$ to 50$^{\circ}C$ increasing the interval of l0$^{\circ}C$ controlled by the constant temperature container. From the results the responses of complex dielectric constant which consist of the real part and imaginary parts have the effect of volumetric water content and concentration of salinity at 1GHz. Use of derived equations (1) and (2) can be calculated the physical parameters such as volumetric water content and salinity concentration of unsaturated media by the responses of complex dielectric constant.

• 한국콘텐츠학회논문지
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• 제9권1호
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• pp.131-138
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• 2009

본 논문은 유비쿼터스 환경의 핵심 기술인 RFID(Radio Frequency IDentification) 기술과 이동통신 기술의 접목을 통해 도래하게 될 모바일 RFID 서비스 환경에서의 성인 인증에 관한 것으로, 기존의 인터 넷에서 행하고 있는 단순한 성인 인증의 단점을 극복하기 위하여, 콘텐츠의 내용에 기반한 등급 분류 체계를 갖추고, 이를 통한 성인 인증 시스템을 제안한 것이다. 우선 기존의 성인 인증 방법에 대하여 설명하고, 청소년들에게 유해 정보가 노출되는 것을 막기 위한 콘텐츠 내용에 기반한 등급 분류 기준에 대하여 알아본다. 그리고, 제안하는 모바일 RFID 성인 인증 데이터의 구성을 살펴본 후, 모바일 RFID 성인 인증 시스템을 제안하고 결론을 맺는다.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.207-214
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• 2002

Food preference of children may be determined by various lifestyle and environmental factors. This study evaluated the effect of rural or urban inhabitance, cooking methods, and frequency of exposure to vegetable dishes on the acceptance of vegetables by 452 fifth grade children. The subjects were students utilizing meal service in public elementary schools in Boryeoung-city, Chungcheong-nam-do (urban); Cheolwon-gun, Gangwondo (rural); or Pocheon-gun, Kyeonggi-do (suburban). A survey was used to determine the preference of students for 59 foods containing vegetables as a primary ingredient, and categorized by fat content (high, low, or intermediate). Children with working mothers and those living in urban areas tended to have less preference for vegetables than their counterparts in rural areas or with mothers who remained at home. Preference for vegetable foods was correlated with the frequency that vegetable foods were prepared by mothers. Vegetable dishes with a high fat content were preferred over those with low or intermediate fat content, except far soup. This study suggests that children who live in urban areas and whose mothers work outside of the home may be predisposed to nutritional deficiencies due to poor acceptance of vegetable foods, and that all children may be at risk for over-consumption of dietary fat, due to a preference for high fat foods.

• 한국컴퓨터정보학회논문지
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• 제20권8호
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• pp.7-13
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• 2015

Recently, there are serviced user customized advertisement of various type using smart device. Representative services are advertisement service using light of smart TV screen or audible sound of smart TV to transmit advertisement information. However, those services have to do a specific action of smart device user for advertisement information or need audible audio information of TV contents. To overcome those weakness, therefore, we propose an advertisement method using inaudible sound of speaker based on smart device. This method supports the transfer of advertising content to the smart device user with no additional action or TV audio signal required to access that content. The proposed method used two high frequencies among 18kHz ~ 22kHz of audible frequency range which smart TV can send out. And it generates those frequencies synthesized with audio of TV contents as trigger signal which can send advertisements to smart device. Next, smart device analysis the trigger signal and request advertisement contents related to the signal to server. After then, smart device can show the downloaded contents to user. Because the proposed method uses the high frequencies of sound signals via the inner speaker of the smart device, its main advantage is that it does not affect the audio signal of TV content. To evaluate the efficacy of the proposed method, we developed an application to implement it and subsequently carried out an advertisement transmission experiment. The success rate of the transmission experiment was approximately 97%. Based on this result, we believe the proposed method will be a useful technique in introducing a customized user advertising service.

• 한국육종학회지
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• 제43권1호
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• pp.14-22
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• 2011

In this study, 15 simple sequence repeat (SSR) markers were used to analyze the population structure of 55 mungbean accessions (34 from South Asia, 20 from West Asia, 1 sample from East Asia). A total of 56 alleles were detected, with an average of 3.73 per locus. The mean of major allele frequency, expected heterozygosity and polymorphic information content for 15 SSR loci were 0.72, 0.07 and 0.33 respectively. The mean of major allele frequency was 0.79 for South Asia, and 0.74 for West Asia. The mean of genetic diversity and polymorphic information content were almost similar for South Asian and West Asian accessions (genetic diversity 0.35 and polymorphic information content 0.29). Model-based structure analysis revealed the presence of three clusters based on genetic distance. Accessions were clearly assigned to a single cluster in which >70% of their inferred ancestry was derived from one of the model-based populations. 47 accessions (85.56%) showed membership with the clusters and 8 accessions (14.54%) were categorized as admixture. The results could be used to understanding the genetic structure of mungbean cultivars from these regions and to support effective breeding programs to broaden the genetic basis of mungbean varieties.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.780-791
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• 2023

To study oscillation characteristic of steam and non-condensable gas direct contact condensation through multi-hole sparger at low mass flux, a series of experiments of pure steam and mixture gas condensation have been carried out under the conditions of steam mass flux of 20-120kg/m²s, water temperature of 20-95 ℃ and mass fraction of non-condensable gas of 0-5%. The regime map of pure steam condensation through multi-hole sparger is divided into steam chugging, separated bubble, aggregated bubble and escaping aggregated bubble. The bubbles behavior of synchronization in the same hole columns and desynchronized excitation between different hole columns can be found. The coalescence effect of mixture bubbles increases with water temperature and non-condensable gas content increasing. Pressure oscillation intensity of pure steam condensation first increases and then decreases with water temperature increasing, and increases with steam mass flux increasing. Pressure oscillation intensity of mixture gas condensation decreases with water temperature and non-condensable gas content increasing, which is significantly weaker than that of pure steam condensation. The oscillation dominant frequency decreases with the rise of water temperature and non-condensable gas content. The correlations for oscillation intensity and dominant frequency respectively are developed in pure steam and mixture gas condensation at low mass flux.