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Feature Extraction for Bearing Prognostics based on Frequency Energy (베어링 잔존 수명 예측을 위한 주파수 에너지 기반 특징신호 추출)

  • Kim, Seokgoo;Choi, Joo-Ho;An, Dawn
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.16 no.2
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    • pp.128-139
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    • 2017
  • Railway is one of the public transportation systems along with shipping and aviation. With the recent introduction of high speed train, its proportion is increasing rapidly, which results in the higher risk of catastrophic failures. The wheel bearing to support the train is one of the important components requiring higher reliability and safety in this aspect. Recently, many studies have been made under the name of prognostics and health management (PHM), for the purpose of fault diagnosis and failure prognosis of the bearing under operation. Among them, the most important step is to extract a feature that represents the fault status properly and is useful for accurate remaining life prediction. However, the conventional features have shown some limitations that make them less useful since they fluctuate over time even after the signal de-noising or do not show a distinct pattern of degradation which lack the monotonic trend over the cycles. In this study, a new method for feature extraction is proposed based on the observation of relative frequency energy shifting over the cycles, which is then converted into the feature using the information entropy. In order to demonstrate the method, traditional and new features are generated and compared using the bearing data named FEMTO which was provided by the FEMTO-ST institute for IEEE 2012 PHM Data Challenge competition.

The Impact of Outside Directors' Characteristics on Performance: Focused on KOSDAQ and NASDAQ IPO Firms (사외이사 특성과 주식성과 : KOSDAQ, NASDAQ IPO기업을 중심으로)

  • Jeon, Ho-Jin
    • Management & Information Systems Review
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    • v.29 no.1
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    • pp.1-23
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    • 2010
  • This study examines the impacts of outside directors' characteristics and compensation on stock performances of KOSDAQ and NASDAQ IPO firms. The results of this study indicated the following interesting results. First, there is no significant relation between outside directors' age and CARs on KOSDAQ firms. while significant positive relation between outside directors' age and CARs on NASDAQ firms. And the elder age group shows a more positive impact on performances compared with the younger age group. Second, there is no relation between outside directors' academic background and CARs for KOSDAQ firms. But We find a significantly positive one for NASDAQ firms. Third, In Relation to outside directors' careers, their professional or CEO careers group have more positive impact on stock performances than gray directors' careers group. Lastly, there is an insignificant negative relation between the outside directors' compensation and CARs for KOSDAQ firms. while there is a positive relative for NASDAQ firms. In particular, there is a significant positive relative between value of stock options and CARs for NASDAQ firms. from the result, I could find out the stock option for outside' directors have a positive influence on firm value.

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A Study on the Types and Management of Old Maps Collected by Library and Museum in Korea (우리나라 도서관.박물관 소장 고지도의 유형 및 관리 실태 연구)

  • Kim, Ki-Hyuk
    • Journal of the Korean Geographical Society
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    • v.41 no.6 s.117
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    • pp.714-739
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    • 2006
  • This study is to analyze the types and management of old maps collected by library and museum in Korea. About 1,200 items of old maps are collected in 39 institutes. This distribution is due to the scatter during late Joseon period through Japanese imperialism period. Half and half of old maps are reserved in museum and library. Atlas of county maps are reserved mainly in Gyujanggak, the National Library of Korea and Library of Korea University There are 10 copies of $\lceil$cheonggu-do(靑邱圖)$\rfloor$ and 25 copies of $\lceil$Daedongyeo-jido(大東輿地圖)$\rfloor$ put in together in all instutes. Forms of those maps in terms of size, picture and place names recorded are different between each other. Methods of management of those maps are different between library and museum. Old maps are treated as rare old books in library, but as traditional old picture in museum. Methods and levels of opening to public of maps are also different in each institute. More serious thing is that there is no specialist in old maps in most institutes.

기능성 식이섬유 소재의 생산기술

  • 김종태
    • Proceedings of the Korean Journal of Food and Nutrition Conference
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    • 2000.05a
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    • pp.5-7
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    • 2000
  • 국내에서의 식이섬유의 이용은 대부분 저분자량의 수용성 식이섬유를 이용한 음료형태가 주류를 이루고 있으며, 밀기울, 귀리, 옥수수 껍질 등으로 부터 얻는 불용성 식이섬유는 제과 및 제빵등에 이용되어 오고 있다. 수용성 식이섬유는 혈중 콜레스테롤을 저하시키며, 불용성 식이섬유는 변비예방과 장기능 증진효과가 탁월한 것으로 알려져 있다. 그러므로, 대장암과 변비같은 장질환 환자가 날로 증가하고 있는 상황에서 국내산 미이용 자원으로부터 불용성 식이섬유의 기능성 향상과 활용기술을 개발하는 것은 식품산업적 가치가 크다고 할 수 있다. 또한, 국내에서 소비되고 있는 폴리덱스트로스와 올리고당과 같은 기능성 당류의 대부분이 외국에서 수입하여 국내에 보급되고 있기 때문에 큰 외화지출이 되고 있다. 따라서 본고에서는 국내산 미곡 부산물인 밀기울 식이섬유 세포벽의 불용성 구조를 수용성으로 변화시킬 수 있는 변형기술과 얻어진 수용성 식이섬유 소재의 특성을 소개하고자 한다. 즉, 밀기울 세포벽의 수용화를 위한 가공처리는 압출성형 공정에 의하여 실시하였으며, 수용화가 수반되는 압출성형 조건에 따른 식이섬유 소재의 이화학적 특성과 수용화가 일어난 세포벽 성분의 분해기작에 대한 연구결과를 정리하였다. 그리고, 현행 올리고당과 식이섬유의 산업적 생산공정에서 문제점으로 대두되고 있는 효소처리, 산성하에서의 감압가열, 고점도 원료물질의 이송, 생물공학적 공정제어, 반응시간, 잔여 효소의 불활성화 및 재활용, 제조원가 상승 등과 같은 것을 해결하거나 개선할 수 있는 효율적인 압출반응공정의 조건과 생산된 소재 glucooligosaccharide, fructooligosaccharide, galactooligosaccharide 등의 특성에 대하여 논하여 보기로 한다.경우가 많지 않다. 또한 그 발생 경위나 원인요소에 대해서는 일반에게 공개되지 않고 있어, 우리가 실천하여 식중독을 예방할 수 있는 정보가 함께 제시되지 못하는 형편이다. 따라서 본 고에서는 최근 수년간 외국에서 학교급식을 비롯한 집단급식 등에서 발생한 식중독 사례를 중심으로 고찰, 분석하였다. 이로부터 식중독 발생에 기여한 주요 원인을 찾아내고 여기서 얻어지는 교훈을 토대로 식중독 발생을 예방 및 최소화할 수 있는 실천적 대처 방안을 모색해 보고자 한다.중의 E. coli O157:H7이 연관되어있다는 보고도 있다. 목장 방문시 원유를 마신 어린이에서 HUS가 유발하였고, 균분리 결과, 농장의 소와 어린이에서 유사한 E. coli O157:H7이 분리된 바 있다. 본 연자들은 베로톡신 유형, plasmid profiles, RFLP 분석, phage type을 기초로하여 소에서 분리된 E. coli O157:H7이 사람유래주와 매우 유사함을 확인하였다.mm 및 2-6mm 난포에서의 101개(67.8%) 및 47개(50.0%) 보다 매우 낮게 나타났다. 전체 회수 난포란수도 4등급이 59.1%(149/252)로써 1, 2, 3등급의 0.4% (1/252), 7.6%(19/252) 및 32.9%(83/252)보다 높게 나타났다. 1회 평균 회수 난포란은 $\leq$2mm 난포에서 4.8$\pm$3.7개로써 2-6mm(3.0$\pm$3.4개) 및 $\geq$6mm (0.3$\pm$0.6개)보다 높았으며, 1회당 평균 8.1$\pm$5.1개의 난포란을 회수하였다. investigation can be separated into sa

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The Present Situation of Patented Technology on Tufgrass Cultivar in Domestic and Foreign (국내외 잔디 특허기술 및 품종 특허의 현황 I)

  • Youn Seong-Ho;Lee Jae Pil;Kim Doo Hwan
    • Asian Journal of Turfgrass Science
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    • v.19 no.2
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    • pp.141-149
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    • 2005
  • This study was carried out to assess the present condition of domestic and foreign patented technologies in turfsrass cultivar area. Patented technologies about turfsrass were analyzed by web site(www.kipris.or.kr) from 1948 to 2005. The results are summarized as follows; 1. Number of patents on turfgrass fertilizer(866) was more than the other patents on turfgrass. 2. Total number of Japan's patents on turfgrass was 1,565. This is more than America's. The foreign patents are mostly on cultivar, sod, seed, disease, construction, and management. 3. Number of patents from company(2,328) was the most and the others are private individuals, research institutes, university professors. However commercialization rate of patants was low. 4. Turfgrass cultivars patented in Korea are 'Konwoo', 'Senock' 'Anyanjungji', etc., and in foreign countries 'Zenith', 'Miyako', etc. Among them 'Zenith', 'Miyako' and 'Konhee' were commercialized.

Optimal Channel Power Allocation by Exploiting Packet Semantics for Real-time Wireless Multimedia Communication (실시간 멀티미디어 통신을 위한 의미 기반 채널 파워 할당 기법)

  • Hong, Sung-Woo;Won, You-Jip
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.47 no.1
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    • pp.171-184
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    • 2010
  • In this work, we develop a novel channel power allocation method for the real-time multimedia over the wireless network environment. Since each frame has different effect on the user perceivable QoS, improving packet loss does not necessarily coincide with perceivable improvements in QoS. A new channel power control scheme is suggested based on the quantified importance of each frame in terms of user perceivable QoS. Dynamic programming formulation is used to obtain optimal transmit power which minimizes power consumption and maximizes user perceivable QoS simultaneously. The experiment is performed by using publicly available video clips. The performance is evaluated using network simulator version 2 (NS 2) and decoding engine is embedded at the client node, and calculated PSNR over the every frame transmitted. Through the semantics aware power allocation (SAPA) scheme, significant improvement on the QoS has been verified, which is the result of unequal protection to more important packets. SAPA scheme reduced the loss of I frame by upto 27% and reduced power consumption by upto 19% without degradation on the user perceivable QoS.

Conceptualization of Defense Industrial Security in Relation to National Security (국가 안보와 연계한 방위산업 보안 개념 정립)

  • Go, Hee-Jae;Lee, Yong-Joon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.265-270
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    • 2019
  • In order to protect the advancement of defense technology that has a tremendous e?ect on both the national security and the economy, the Republic of Korea established the Defense Technology Security Act in 2015. As the new enactment brought changes to the landscape of the defense industry and defense industrial security, a new examination of the concept of the defense industrial security has now become necessary. Even after taking into consideration the undisclosed nature of defense industrial security research, and the fact that only the limited number of firms participates in the subject matter, scientific studies related to the topic have not been active. However, with the new enactment of the Defense Technology Security Act, it is necessary to expand the scope of security and to redefine the concept of defense industrial security. In this paper, we analyzed the research works on related technology protection policies and our environment of the defense industry in order to conceptualize defense industrial security. The established concepts are expected to provide a systematic way to protect the confidential and defense technology.

Progress and Prospect of Research on Old Maps in Korea (우리나라 고지도의 연구 동향과 과제)

  • Kim, Ki-Hyuk
    • Journal of the Korean association of regional geographers
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    • v.13 no.3
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    • pp.301-320
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    • 2007
  • In Korean academic societies, old maps has not yet been properly investigated in terms of their genealogy, classification, detailed place names, historical backgrounds and the other aspects. With publication of the bibliographies and papers on old maps reserved in museum and library, the scope of research enlarged gradually its scope from 1970s. In 1980s, with the development of theoretical geography, scientific analysis were applied to investigate the projection method of Daedongyeo-jido. The 1990s proved a prominent decade for researches. The photo-copies of old maps enabled researchers to investigate the in-depth comparative study. The more important thing is that old maps became to be powerful instrument in the research of historical geography, such as territorial disputes and marine name(東海). And county old maps compiled by region became to be regional-cultural contents of local areas. Important issues in old map research in Korean academic societies are about Cheonha-do which is unique old world map in Korea, grid-system projection in old county maps and the genealogy of Daedongyeo-jido(manuscript and block print edition). This study shows that bibliography of all old maps preserved in each library and museum should be standardized. This could enable the exchange of information of old maps between institutes. The more important thing is that conciliation of human, social and natural sciences should be applied in the research of old maps.

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A Study on the Utilization Method through the Analysis of the Women Leaders Database (여성 인재 데이터베이스 분석을 통한 활용 방안에 관한 연구)

  • Hong, Hee-Jeong
    • Journal of Digital Convergence
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    • v.18 no.2
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    • pp.37-46
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    • 2020
  • The purpose of the study is to look at the status of the women's leaders databases designed to expand women's participation in the public sector, and to come up with measures for the utilization of the women's leaders databases. For this purpose, this study analyzed the current status of the women's leaders databases that have been established and managed by the Ministry of Gender Equality and Family and Incheon Metropolitan Government. And In order to find ways to utilize the database of women leaders, the results of a survey conducted by the Incheon Metropolitan Government were analyzed and policy implications were drawn. The policy implications for utilizing the women's leaders database are as follows: First, systematic management such as the reorganization of the women's leaders database and the updating of the latest information are necessary. Second, it is necessary to disclose the current status of women's leaders and trends in utilization through the website. Third, the follow-up is needed through active monitoring at the national level. And if possible, the results need to be reflected in the agency performance assessment. Fourth, regular and long-term public relations strategies are needed so that the women's leaders database can be used not only for career-breaking women but also for emerging talent. Based on this study, further research on how women who entered the society through the women's leaders database will be representative as social minorities will be needed.

Molecular Identification of Pooideae, Poaceae in Korea (국내 농경지에 발생하는 포아풀아과 잡초의 분자생물학적 동정)

  • Lee, Jeongran;Kim, Chang-Seok;Lee, In-Yong
    • Weed & Turfgrass Science
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    • v.4 no.1
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    • pp.18-25
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    • 2015
  • A universal DNA barcoding for agricultural noxious weeds is a powerful technique for species identification without morphological knowledge, by using short sections of DNA from a specific region of the genome. Two standard barcode markers, chloroplast rbcL and matK, and a supplementary nuclear ribosomal Internal Transcribed Spacer (ITS) region were used to examine the effectiveness of the markers for Pooideae barcoding using 163 individuals of 29 taxa across 16 genera of Korean Pooideae. The rbcL and ITS revealed a good level of amplification and sequencing success while matK did not. Barcode gaps were 78.6% for rbcL, 96.2% for matK, and 91.7% for ITS, respectively. Resolving powers were 89.3% for rbcL, 92.3% for matK, and 79.1% for ITS. The matK obtained the best both barcode gap and resolving power. However, it should be considered not to employ matK for Pooideae barcode because of low rate of PCR amplification and sequencing success. As a single DNA marker, rbcL and ITS were reasonable for Pooideae barcode. Barcode gap and resolving power were increased when ITS was incorporated into the rbcL. The barcode sequences were deposited to the National Center for Biotechnology Information (NCBI) database for public use.