• 제목/요약/키워드: remaining service life

검색결과 96건 처리시간 0.021초

궤도 유지보수 주기 예측을 위한 구간 특성에 따른 궤도틀림 표준편차 진전정도 분석 (Study for Progress Rate of Standard Deviation of Irregularity Based on Track Properties for the Railway Track Maintenance Cycle Analysis)

  • 정민철;김정훈;이지하;강윤석;공정식
    • 한국구조물진단유지관리공학회 논문집
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    • 제16권3호
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    • pp.31-40
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    • 2012
  • 궤도틀림은 열차의 주행안전 및 승차감에 미치는 영향이 크고, 소음 진동의 주요원인으로 작용한다. 따라서 현장에서 발생하는 궤도의 틀림을 체계적으로 분석함으로써 이를 저감할 수 있도록 차량운행 조건과 선로선형 및 궤도구조를 설계하는 것은 중요한 과제이다. 현재 국내에서 EM-120에 의해 검측된 틀림 데이터는 매우 불규칙적인 형태를 나타내며 데이터 분석 시 다양한 문제점을 가지고 있다. 본 연구에서는 궤도의 효율적인 유지관리를 위해 검측된 틀림데이터의 효율적인 처리 기법을 개발하고, 정제된 데이터를 이용해 선로를 구성하고 있는 이음매, 도상, 노반, 체결구 등의 요소를 고려하여 레일 궤도 틀림의 진전 정도를 정량화 하였다. 또한 축적된 검측 데이터로부터 궤도의 건전도를 평가할 수 있는 방법을 정립하고 잔존수명을 예측하여 효율적 유지관리를 실현하기 위하여 검측 데이터의 확률론적 수명 산정 기법 개발 및 데이터를 이용한 구간 특성에 따른 궤도틀림 표준편차의 틀림 진전 정도에 대한 통계 및 확률적 분석을 수행하였다.

형성층 활동 기간을 활용한 일본잎갈나무 식재 및 벌채 적기 추정 (Estimation of the Optimal Periods for Planting and Felling Larix kaempferi Based on the Period of Its Cambial Activity)

  • YOO, Hye-Ji;JU, Jeong-Deuk;PARK, Jun-Hui;SHIN, Chang-Seob;EOM, Chang-Deuk;SEO, Jeong-Wook
    • Journal of the Korean Wood Science and Technology
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    • 제49권5호
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    • pp.399-415
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    • 2021
  • 본 연구는 우리나라 주요 조림수종인 일본잎갈나무 형성층 활동 시기를 모니터링 하여 적절한 식재 및 벌채시기를 제시하기 위해 수행되었다. 또한, 각 지역 일본잎갈나무의 형성층 활동을 유도하는 적산온도도 함께 조사하였다. 연구지는 충청북도에 위치한 월악산과 미동산이다. 월악산과 미동산에서 일본잎갈나무 5본씩을 선발한 후, 월악산에서는 2017년 4월 7일 ~ 10월 6일, 미동산에서는 2017년 4월 7일 ~ 9월 29일까지 직경 2 mm 미니 생장추(trephor)로 형성층 시료를 채취하였다. 채취된 형성층 시료는 PEG2000에 임베딩 한 후, 마이크로톰을 이용하여 두께 10-15 ㎛로 박편 제작을 하였다. 상해세포간구 발생으로 정확한 형성층 활동 모니터링이 불가능한 월악산 일본잎갈나무 1본과 미동산 일본잎갈나무 1본은 연구에서 제외하였다. 현미경으로 월악산과 미동산 일본잎갈나무의 형성층 개시 일을 관찰한 결과, 4월 28일에 월악산에서 2본, 미동산에서 3본이 개시하였다. 나머지인 월악산 2본과 미동산 1본은 일주일 후인 5월 4일에 개시하였다. 형성층 활동 개시를 유도한 적산온도는 월악산의 경우 196.4-271.8이었으며, 미동산은 204.7-277.3로 유사하였다. 형성층 활동 종료는 월악산 8월 4일 ~ 8월 25일, 미동산 8월 4일 ~ 9월 1일이었다. 이상의 결과를 근거로 월악산과 미동산에 적합한 일본잎갈나무 식재 시기는 형성층 활동 약 한 달 전인 4월 이전이며, 벌채 시기는 형성층 활동이 완전히 종료되는 10월부터로 확인되었다.

전립선 비대증에 대한 뜸치료의 효과 : 체계적 문헌고찰과 메타분석 (Moxibustion for Benign Prostatic Hyperplasia: A Systematic Review and Meta-analysis)

  • 배고은;이승환;홍진우;이인;김소연;최준용;한창우;윤영주;박성하;권정남
    • 대한한방내과학회지
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    • 제39권3호
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    • pp.372-388
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    • 2018
  • Objective: This study evaluates the effectiveness and safety of moxibustion for benign prostatic hyperplasia (BPH). Methods: Using the keywords "benign prostatic hyperplasia", "benign prostatic hypertrophy", "benign prostatic enlargement", "prostatic hyperplasia", and "moxibustion", we searched papers in numerous databases, including National Discovery for Science Leaders (NDSL), Korean Traditional Knowledge Portal (KTKP), Oriental Medicine Advanced Searching Integrated System (OASIS), Research Information Sharing Service (RISS), PubMed, Embase, and CENTRAL. The search range included randomized controlled trials (RCTs). Papers not matched with inclusion criteria were excluded. The methodological quality of each RCT was assessed using the Cochrane risk-of-bias tool. Where appropriate, meta-analyses were performed. Results: Initially, 77 studies were found. Of these, 11 duplicate studies were removed and 27 were excluded following title and abstract screening. After the remaining 39 papers were scanned, 13 RCTs were selected and analyzed. Among these 13 RCTs, five compared moxibustion therapy and oral medication, seven compared moxibustion plus acupuncture therapy and oral medication, and one compared moxibustion plus acupuncture therapy and sham-moxibustion. The meta-analysis showed positive results for the use of moxibustion therapy in terms of International Prostate Symptom Score (IPSS), Quality Of Life (QOL), Maximum Flow Rate (Qmax), Prostate Volume (PV), and the efficacy rate. The meta-analysis showed positive results for the use of moxibustion plus acupuncture therapy in terms of IPSS, QOL, and the efficacy rate. Conclusions: This meta-analysis of clinical trials suggests that moxibustion is effective intreating BPH patients. The results of this study could be applied to clinical treatment of BPH. However, additional large-scale clinical researches should be conducted.

우리나라 단독가구의 실태에 관한 소고 (A Study on One Person Households in Korea)

  • 배화옥
    • 한국인구학
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    • 제16권2호
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    • pp.125-139
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    • 1993
  • Korea has successfully achieved a lowered fertility level owing to the strong population control policy and effective family planning program. Along with fertility decline and decreased number of children in family, average number of household members has decreased and nontraditional households such as one person household and households composed of unrelated individuals have prolifirated, even though the absolute number of them are found minimal in Korea. However in recent years several data and survey results suggest that one person households are gradually in the increasing trend. The study aimed at investigating the real state of one person households in Korea and next analyzing the proportional distribution of one person households by a few socioeconomic characteristics, thus providing basic for eatablishing far-singhted population and social welfare policy in the future. Korea has experienced high growth rate of economy through government-led development plans starting from the 1960s. During the past three decades, Korea has shifted from the agricultural state to the industrialized one. In compliance with the economic growth, urbanization and industrialization have brought about rural-to-urban migration and a great bulk of young population migrated to urban areas, who are seeking for educational and job opportunities. Korean society has also been under drastic change in every aspect of life involving norms, tradition, and attitude, etc. Therefore, in spite of the prejudice on 'living alone' still remaining, young people gradually leave parents and home, and further form nontraditional households in urban areas. Current increase in the number of one person households is partly attributable to the increase in high female educational attainment and female participation in economic activities. As the industrial structure in Korea changes from primary into secondary and tertiary industries, job opportunities for service/sales and manufacturing are opened to young female labor force in the process of industrialization. Contrary to the formation of one person households by young people, the aged single households are composed when children in family leave one by one because of marriage, education, employment. In particular, a higher proportion of aged female single households occur in rural areas due to the mortality difference by sex. Based on the data released form the 1990 Population and Housing Census and National Fertility and Family Health Survey in 1985 and 1991, the study tried to examine the state of one person households in Korea. According to Census data, the number of one person households increased to 1, 021, 000 in 1990, comprising 9.0 percent of total households. And the survey reveal that among total 11, 540 households, 8.0 percent, 923 households, are composed of one person households. Generally, the proportion of female single households is greater than that of male ones, and a big proportion of one person households is concentrated in the 25-34 age bracket in urban areas and 65 years and more in rural areas. It is shown than one person householders in urban areas have higher educational attainment with 59.2 percent high schooling and over in 1991, Job seeking proved to be the main reason for leaving home and forming one person households. The number of young female single households with higher education and economic self-reliance are found nil and the study did not allow to analyze the causal realtionship between female education and employment and one person household formation. However more research and deep analysis on the causal facors on one person household formation using statistical method are believed to be necessary.

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무회분 석탄 생산을 위한 온순조건 용매추출 공정의 경제성 분석 (An Economic Analysis of Solvent Extraction Process under Mild Condition for Production of Ash-Free Coal)

  • 최호경;김상도;유지호;전동혁;임정환;임영준;이시훈
    • Korean Chemical Engineering Research
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    • 제50권3호
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    • pp.449-454
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    • 2012
  • 본 연구에서는 석탄의 연화온도보다 낮은 온도에서의 무회분 석탄 제조공정인 온순조건 용매추출 공정의 경제성을 분석하였다. 이를 위해 인도네시아 석탄 산지에 6,000 톤/일 규모의 온순조건 용매추출 플랜트를 건설하는 것으로 가정하였으며, 이 설비에 대하여 $96백만의 투자비용과, 내용년수 15년에 대한 IRR, B/C ratio, NPV, DPP를 계산하였다. 계산 결과 이 플랜트의 IRR은 31%, NPV는 $87백만, B/C ratio는 1.08, DPP는 3.9년인 것으로 계산되었으며, 이를 통해 석탄의 온순조건 용매추출 플랜트는 충분한 경제성이 있는 것으로 판단하였다. 민감도 분석 결과 무회분 석탄의 판매가격보다는 원료탄의 구입가격과 고품위 잔탄의 판매가격이 온순조건 용매추출 플랜트의 경제성을 크게 좌우하였다.

Genotypes of commercial sweet corn F1 hybrids

  • Kang, Minjeong;Wang, Seunghyun;Chung, Jong-Wook;So, Yoon-Sup
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.107-107
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    • 2017
  • Sweet corns are enjoyed worldwide as processed products and fresh ears. Types of sweet corn are based on the gene(s) involved. The oldest sweet corn type has a gene called "sugary (su)". Sugary-based sweet corn was typically named "sweet corn". With its relatively short shelf life and the discovery of a complementary gene, "sugary enhanced (se)", the sweet corn (su only) was rapidly replaced with another type of sweet corns, sugary enhanced sweet corn, which has recessive homozygous su/su, se/se genotype. With the incorporation of se/se genotype into existing su/su genotype, sugary enhanced sweet corn has better shelf life and increased sweetness while maintaining its creamy texture due to high level of water soluble polysaccharide, phytoglycogen. Super sweet corn as the name implies has higher level of sweetness and better shelf life than sugary enhanced sweet corn due to "shrunken2 (sh2)" gene although there's no creamy texture of su-based sweet corns. Distinction between sh2/sh2 and su/su genotypes in seeds is phenotypically possible. The Involvement of se/se genotype under su/su genotype, however, is visually impossible. The genotype sh2/sh2 is also phenotypically epistatic to su/su genotype when both genotypes are present in an individual, meaning the seed shape for double recessive sh2/sh2 su/su genotype is much the same as sh2/sh2 +/+ genotype. Hence, identifying the double and triple recessive homozygous genotypes from su, se and sh2 genes involves a testcross to single recessive genotype, chemical analysis or DNA-based marker development. For these reasons, sweetcorn breeders were hastened to put them together into one cultivar. This, however, appears to be no longer the case. Sweet corn companies began to sell their sweet corn hybrids with different combinations of abovementioned three genes under a few different trademarks or genetic codes, i.g. Sweet $Breed^{TM}$, Sweet $Gene^{TM}$, Synergistic corn, Augmented Supersweet corn. A total of 49 commercial sweet corn F1 hybrids with B73 as a check were genotyped using DNA-based markers. The genotype of field corn inbred B73 was +/+ +/+ +/+ for su, se and sh2 as expected. All twelve sugary enhanced sweet corn hybrids had the genotype of su/su se/se +/+. Of sixteen synergistic hybrids, thirteen cultivars had su/su se/se sh2/+ genotype while the genotype of two hybrids and the remaining one hybrid was su/su se/+ sh2/+, and su/su +/+ sh2/+, respectively. The synergistic hybrids all were recessive homozygous for su gene and heterozygous for sh2 gene. Among the fifteen augmented supersweet hybrids, only one hybrid was triple recessive homozygous (su/su se/se sh2/sh2). All the other hybrids had su/su se/+ sh2/sh2 for one hybrid, su/su +/+ sh2/sh2 for three hybrids, su/+ se/se sh2/sh2 for three hybrids, su/+ se/+ sh2/sh2 for four hybrids, and su/+ +/+ sh2/sh2 for three hybrids, respectively. What was believed to be a classic super sweet corn hybrids also had various genotypic combination. There were only two hybrids that turned out to be single recessive sh2 homozygous (+/+ +/+ sh2/sh2) while all the other five hybrids could be classified as one of augmented supersweet genotypes. Implication of the results for extension service and sweet corn breeding will be discussed.

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