• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.707-708
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• 2008

본 논문에서는 초전도 플라이휠 에너지 저장장치 (Superconductor Flywheel Energy Storage System : SFES)의 에너지 변환을 위해 사용된 영구 자석형 전동 발전기(Permanent Magnet Synchronous Motor/Generator : PMSM/G)가 SFES의 에너지 저장효율에 미치는 영향을 평가하였다. SFES 시스템은 YBCO 벌크 초전도체를 이용한 저어널 타입(journal type)의 초전도 베어링을 사용하였으며, 슬롯리스 형 PMSM/G를 사용하였다. PMSM/G의 고정자 코어, 누설 자속 및 감겨진 코일에 의한 저장 에너지 손실을 측정하였다. 사용된 코어의 크기, 누설자속, 및 코일의 적절한 선정을 통하여 저장된 에너지의 손실을 상당히 줄일 수 있음을 확인하였다. 또한 영구자석과 코어가 동시에 회전하는 회전 코어형 전동발전기를 적용하여 에너지 손실을 매우 감소시킬 수 있음을 확인하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.316-316
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• 2007

리튬폴리머 전지용 정극활물질인 $LiFePO_4$를 수열법으로 합성하였다. 제조한 정극활물질 $LiFePO_4$는 X-ray 회절분석을 통하여 olivine 구조임을 확인하였다. 전극 제조 시 첨가된 도전재의 종류에 따른 전기화학적 특성변화를 알기 위하여, Acetylene Black, Super-Black, Multi-Walled Carbon Nanotube(MWCNT), SP270을 도전재로 제조된 정극활물질과 PVDF를 결합제로 사용하였다. 셀은 제조된 정극과 고체전해질 $25PVDFLiCIO_4EC_{10}PC_{10}$를 사용하고, 부극은 금속리튬으로 coin 타입의 cell을 조립하여 충방전을 진행하였다. 충방전 진행결과, Multi-Walled Carbon Nanotube(MWCNT)를 도전재로 사용하였을 경우, 초기 방전용량은 94mAh/g, 100cycle 후에는 약 93mAh/g인 기타 도전재를 사용하였을 때보다 안정하고 높은 방전용량을 나타내었다. 이때의 충방전 전류밀도는 0.1mAh/g이고 전압범위 는 2.5~4.3V이었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.174-175
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• 2019

Recently, due to air pollution caused by fine dust, it is considered as a social problem. Increasing fine dust has intensified air pollution, causing many diseases and damages. This year, Seoul, South Korea, reached a severe level of fine dust pollution worldwide. The Ministry of Environment has strengthened the environmental standard for fine dust (PM2.5) from $50{\mu}g/m^3$ to $35{\mu}g/m^3$ since March 2018. When fine dust enters the human body, it causes bronchial or skin elongation such as respiratory allergies, irritable pneumonia, asthma and atopy. In this study, $TiO_2$ rutile with photocatalytic activity was used, and materials prepared by rutile sulfuric acid method were used. The photocatalytic activity rate is 95% or more and the density is $4.1g/cm^3$. The matrix was based on cement, and the substitution rate of $TiO_2$ was 0, 5, 10, 15, 20 (%). The test item is flexural strength and compressive strength.

• Journal of Platform Technology
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• v.12 no.1
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• pp.77-84
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• 2024

With the recent increase in the use of artificial intelligence, AI TRiSM data management within organizations has become important, and thus securing data reliability has emerged as an essential requirement for data-based decision-making. Digital content is transmitted through the unreliable Internet to the cloud where the digital content storage is located, then used in various applications. When detecting anomaly of data, it is difficult to provide a function to check content modification due to its damage in digital content systems. In this paper, we design a technique to guarantee the reliability of video data by expanding the function of data annotation. The designed annotation technique constitutes a prototype based on gRPC to handle a request and a response in a webUI that generates classification label and Merkle tree of given video data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.236-242
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• 2019

Recently, scanning projects have been carried out in various construction and construction fields for maintenance purposes. The point cloud generated by the scan results is composed of a number of points representing the object to be scanned. The process of extracting the necessary information, including dimensions, from such scan data is called paradox. The reverse engineering process of modeling a point cloud as BIM involves considerable manual work. Owing to the time-consuming reverse engineering nature of the work, the costs increase exponentially when rework requests are made, such as design changes. Reverse engineering automation technology can help improve these problems. On the other hand, the reverse design product is variable depending on the use, and the kind and detail level of the product may be different. This paper proposes the G2BM (Geometry-to-BIM mapping) rule definition method that automatically maps a BIM object from a primitive geometry to a BIM object. G2BM proposes a process definition and a customization method for reverse engineering BIM objects that consider the use case variability.

• Electronics and Telecommunications Trends
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• v.13 no.1 s.49
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• pp.52-62
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• 1998

본 고에서는 도서관의 문헌제공 서비스 차원에서 연구되고 있는 프로젝트와 전자 문헌전달 시스템의 프로토타입을 조사, 분석하였다. 전자 문헌전달 시스템이란 출판사나 도서관에서 기존의 인쇄물 출판 및 배포를 낭가하는 전자적인 방법, 즉 비디오텍스, 전자우편, 온라인 네트워크 및 CD-ROM 등을 통해 이용자에게 필요한 정보를 전달하는 시스템을 뜻한다. 현재 활용가능한 전자 문헌전달 시스템을 중심으로 그 이용 및 접속방법, 제공가능한 문헌의 형태, 서비스 제공에 필요한 기술적 장비와 네트워크에 관련된 요구사항 그리고 주제분야 및 비용 등에 관한 사항들을 중점적으로 조사하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3C
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• pp.271-280
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• 2008

M channel near-perfect-reconstruction(NPR) pseudo-QMF banks are a hybrid of conventional pseudo-QMF design and spectral factorization approach where the analysis and synthesis filters are cosine-modulated versions of the prototype-lowpass filter(p-LPF). However, p-LPF H(z) does not have linear-phase symmetry as well as magnitude-distortion optimization since it is obtained by spectral factorization of $2M^{-th}$ band filter $G(z)=z^{-(N-1)}H(z^{-1})H(z)$. A fair amount of attention, therefore, has been focused on the design of filter banks for reducing only alias-cancellation distortion without reconstructed-amplitude distortion. In this paper, we propose a new method for designing linear-phase p-LPF in NPR pseudo-QMF banks, which is based on Maxflat(maximally flat) FIR filters with closed-form transfer function. In addition, p-LPF H(z) is optimized in this approach so that the 2M-channel overall distortion response represented with $G(z)=H^2(z)$ approximately becomes an unit magnitude response. Through several examples of NPR pseudo-QMF banks, it is shown that the peek ripple of the overall magnitude distortion is less than $3.5{\times}10^{-4}\;({\simeq}-70dB)$ and analysis/synthesis filters have the sharp monotone-stopband attenuation exceeding 100 dB.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.853-859
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• 2011

We developed and investigated sugar-soaked black soybean snack (SSBSS) to increase the availability of black soybean. The most desirable moisture contents and texture properties of hardness and gumminess in preparing SSBSS were obtained at a sugar concentration of $40^{\circ}brix$ for the first sugar soaking step and $50^{\circ}brix$ for the second sugar soaking process. Sensory evaluation also showed that SSBSS prepared with $40^{\circ}brix$ for first sugar soaking step and $50^{\circ}brix$ for the second sugar soaking process was graded higher than the other samples in all questionnaires. Prepared SSBSS had a final moisture content of $5.50{\pm}0.39%$, crude protein content of $16.25{\pm}0.07%$, and crude lipid content of $34.26{\pm}3.95%$. The ash and carbohydrate contents of SSBSS were $0.51{\pm}0.05%$ and $43.48{\pm}0.01%$, respectively, and the final glucose content was $10.20{\pm}0.10^{\circ}brix$. GABA concentration was $15.24{\pm}1.47\;mg$/g and the contents of daidzein, genistein, daidzin, and genistin were $695.7{\pm}6.08\;{\mu}g$/g, $810.6{\pm}3.9\;{\mu}g$/g, $755.8{\pm}39.6\;{\mu}g$/g, and $1640.7{\pm}390.8\;{\mu}g$/g, respectively. In addition, the phenolic compound and flavonoid contents in SSBSS were $0.16{\pm}0.01$ and $2.33{\pm}0.40\;mg$/g, respectively.

• Information Systems Review
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• v.8 no.1
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• pp.181-201
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• 2006

As the Internet spreads, many people have interests in e-CRM and product recommender systems, one of e-CRM applications. Among various approaches for recommendation, collaborative filtering and content-based approaches have been investigated and applied widely. Despite their popularity, traditional recommendation approaches have some limitations. They require at least one purchase transaction per user. In addition, they don't utilize much information such as demographic and specific personal profile information. This study suggests new hybrid recommendation model using two data mining techniques, association rule and classification, as well as intelligent agent to overcome these limitations. To validate the usefulness of the model, it was applied to the real case and the prototype web site was developed. We assessed the usefulness of the suggested recommendation model through online survey. The result of the survey showed that the information of the recommendation was generally useful to the survey participants.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.83-87
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• 2012

Activated carbon fiber (ACF) was used to remove four kinds of trihalomethanes(THMs) from tap water which were remained as by-products during the chlorination of water. Adsorption capacity was investigated as a function of THMs concentration and solution temperature, and adsorption mechanism was studied in relating to the surface characteristics of ACF. All the four kinds of THMs were rapidly adsorbed on the surface of ACF by physical adsorption due to the enormous surface micropores and chemical adsorption due to the hydrogen bonds, showing a Langmuir type adsorption isotherm. Langmuir type is especially profitable for the adsorption of low level adsorptives. ACF was very effective for the removal of THMs from tap water because the THMs concentration is below $30{\mu}g/L$ in tap water. The adsorption amount of THMs on ACF increased in order of the number of brom atom; chloroform, bromodichloromethane, dibromochloromethane, and bromoform. The adsorption capacity increased as increasing the number of brom atom due to the decrease of polarity in solution. The adsorption capacity of THMs on ACF can be enhanced by proper surface treatment of ACF.