• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.452-455
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• 2005

Today the tastes of consumers change rapidly and the kinds of the products become diverse. Therefore the product life cycle becomes shorter and shorter. Moreover the save of resources and the recycling for the environmental preservation are the essential theme. On this the necessary information for the product development increases enormously. For the right use of the information the design process should be supported by the proper design tool. For this the 'design catalogue system for recycling' is suggested here. This system consists of four parts, that is, 'the existing automobile system database', 'working principle database', 'assessment system of the ease of disassembly' and 'one's own product development database' By the use of this system the product development period could be reduced about 30% drastically.

• 한국IT서비스학회지
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• 제21권6호
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• pp.91-116
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• 2022

This research shows how the perception of digital shadow work varies depending on the user's period of use of digital services in applications, which are key areas of digital services. The purpose of this research is to investigate how the digital shadow work type changes over time. This research adopted a qualitative research method for location-based service "help application" users and examined the change in perception from the app service acceptance stage to the app service continuous use stage with two-times interviews of ten users by a longitudinal research design. This study conducted a longitudinal analysis focusing on how digital shadow work occurs in the application subscription process, exploring phenomenologically how the type changes throughout the process over time.

• 대한안전경영과학회지
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• 제12권1호
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• pp.63-69
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• 2010

This study is to find out why drivers used to put pseudo-petroleum in their cars and to fundamentally remove any accidents from the misuse. Questionnaire survey has been made in Gimpo area where many drivers can use it comparatively easily outside of Seoul. And they are analyzed statistically using SPSS 12.0 package program. Correlation factor is shown with 0.683, very high relationship between using frequency and use period of cars. It is shown that important factor to give impact to consumer attitude has been produced as car-using period, education level. The longer the cars have been used, the more pseudo petroleum has been used, it is found.

• 한국지반환경공학회 논문집
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• 제20권12호
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• pp.33-39
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• 2019

The upsurge of population, internal migration, economic activities and developmental works has brought significant land use and land cover (LULC) change over the period of 1990 and 2010 in the Bagmati basin of Nepal. Along with alteration on various other ecosystem services like water yield, water quality, soil loss etc. carbon sequestration is also altered. This study thus primary deals with evaluation of LULC change and its impact on the soil carbon storage for the period 1990 to 2010. For the evaluation, InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Carbon model is used. Residential and several other infrastructural development activities were prevalent on the study period and as a result in 2010 major soil carbon reserve like forest area is decreased by 7.17% of its original coverage in 1990. This decrement has brought about a subsequent decrement of 1.39 million tons of carbon in the basin. Conversion from barren land, water bodies and built up areas to higher carbon reserve like forest and agriculture land has slightly increased soil carbon storage but still, net reduction is higher. Thus, the spatial output of the model in the form of maps is expected to help in decision making for future land use planning and for restoration policies.

• 한국농공학회논문집
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• 제51권3호
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• pp.25-35
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• 2009

Climate change due to global warming possibly effects the agricultural water use in terms of evapotranspiration. Thus, to estimate rice evapotranspiration under the climate change, future climate data including precipitation, minimum and maximum temperatures for 90 years ($2011{\sim}2100$), were forecasted using LARS-WG. Observed 30 years ($1971{\sim}2000$) climate data and climate change scenario based on SRES A2 were prepared to operate the LARS-WG model. Using these data and FAO Blaney-Criddle method, reference evapotranspiration and rice evapotranspiration were estimated for 9 different regions in South Korea and rice evapotranspiration of 10 year return period was estimated using frequency analysis. As the results of this study, rice evapotranspiration of 10 year return period increased 1.56%, 5.99% and 10.68% for each 30 years during $2011{\sim}2100$ (2025s; $2011{\sim}2040$, 2055s; $2041{\sim}2070$, 2085s; $2071{\sim}2100$) demonstrating that the increased temperature from the climate change increases the consumptive use of crops and agricultural water use.

• Journal of the Korean Data and Information Science Society
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• 제25권1호
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• pp.11-18
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• 2014

연구의 목적은 인터넷 설문조사에서 자료의 정확성을 데이터베이스의 자료와 설문조사 자료의 비교를 통해 검정하는 것이다. 설문조사는 2012년 8월 한국과학기술정보연구원의 NDSL 원문이용자를 대상으로 실시하였으며, 검증에 이용된 변수는 나이, 소속기관의 인구통계적 변수와 이용빈도, 이용기간의 행동 변수이다 1차 검정결과 불일치 비율은 나이가 7.5%, 소속기관 15%, 이용빈도 92%, 이용기간 55%로 높게 나타났다. 상세검정을 통해 나이에 대한 불일치 비율을 비관적으로 3%, 낙관적으로 1%로, 소속기관에 대한 불일치 비율을 비관적으로 4.5%, 낙관적으로 2%로 추정할 수 있었다. 불일치비율을 1/4 이하로 대폭 축소시켰다. 이용빈도와 이용기간은 측정오차와 응답자의 기억력 문제, 인터넷 이용행태 등으로 불일치 비율이 높게 나타났다. 이러한 현상은 전통적 설문조사에도 간접적으로 적용될 수 있을 것이다. 본 연구의 결과는 인터넷 설문조사가 믿을만한 자료라는 점을 시사하고 있으며, 보다 정확한 검증을 위해 많은 후속 연구가 필요하다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.217-223
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• 1998

This study was performed to figure out water consumption of the twisted sweet pepper in a greenhouse. Obtained results are as follows; 1. The ambient temperature was nearly same as the normal year, while the average air temperature and the relative humidity in the green house were little bit higher than those of the outside condition. The transparency of the greenhouse roof was approximately 50%. The total amount of rainfall during the irrigation period was 1,040㎜ which is 350㎜ higher than 1997 during the same period. 2. In case of pot cultivation, as the saturation ratio was increased, the aeaf area and plant height and yield were also increased. The yield from the field cultivation was higher than the average yield from the pot cultivations which are treated by three levels of saturation ratio. 3. The variation of daily consumptive use of the twisted sweet pepper was very large in it's range. In case of the pot cultivation, as the saturation was increased, the daily and the total consumptive use were increased. 4. The daily consumptive use was strongly correlated with the ambient temperature, while it was weakly correlated with the relative humidity and solar radiation. 5. There were close correlation between plant environment; leaf area, plant height and yield, and consumptive use. As the saturation ratio was increased, the correlation between those plant factors and consumptive use was getting stronger.

• 한국환경생태학회지
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• 제23권3호
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• pp.250-257
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• 2009

2006년부터 2008년까지 월동기(10월$\sim$3월)동안 한강하구에 도래하는 재두루미의 서식지 이용현황을 조사하였다. 월동개체군은 평균 106.6개체(SD=27)가 관찰되었으며, 2008년 1월초에 최대 140개체가 관찰되었다. 재두루미는 농경지와 갯벌을 같이 이용하였으며, 월동기 동안농경지와 갯벌의 이용율에 유의한 차이를 보이지 않았다(Mann-Whitney test. p=0.4). 시기별 이용율은 월동초기에는 농경지의 이용율이 높았으며, 월동후기에는 갯벌의 이용율이 높았다(Maul-Whitney test. 월동초기: p<0.01, 월동후기: p<0.01). 월동중기에는 농경지와 갯벌의 이용율에 차이가 없었다. 농경지는 홍도평, 평동, 이화동, 장항논을 모두 이용하였으며, 홍도평의 이용율이 높았다. 각 농경지간 이용율은 월동초기와 중기에 유의한 차이를 보였다(Kruskal-wallis test. p<0.05). 갯벌은 김포대교$\sim$누산리 구간을 이용하였으며, 김포대교$\sim$일산대교 상류구간의 이용율이 높았다. 각 구간별 이용율은 시기별로 유의한 차이가 있었다(Kruskal-wallis test. p<0.01).

• Journal of applied mathematics & informatics
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• 제36권5_6호
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• pp.491-504
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• 2018

In this article, we consider a fourth order nonlinear difference system. By making use of the critical point theory, we obtain some new existence theorems of at least one periodic solution with minimal period. Our main approach used in this article is the variational technique and the Saddle Point Theorem.

• 분석과학
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• 제35권6호
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• pp.267-273
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• 2022

본 연구에서는 어묵의 유통기한을 소비기한으로 변경하기 위해 품질평가를 진행하였다. 제품 품질 평가를 위해 보관 조건은 5, 10, 15 ℃로 설정하고 pH, 산가, 휘발성염기질소, 세균수, 대장균군 등 5가지 항목에 대한 실험을 진행하였다. 실험결과 어묵의 품질유지한계기간은 5 ℃에서 43일, 10 ℃에서 30일, 15 ℃에서 7일이었다. 품질평가에 사용된 5가지 시험항목 중 품질한계지표가 있는 항목은 산가, 세균수, 대장균군이었다. 그리고 3가지 보관조건에서 품질유지한계기간을 결정하는 지표는 세균수였다. 본 실험에 사용된 어묵의 유통기한은 10일이나 품질평가를 통해 10 ℃에서의 소비기한은 28.5일로, 품질유지한계기간인 30일에 안전계수 0.95를 곱한 값이다. 그러나 본 연구는 1개 업체의 어묵 1품목에 대한 품질평가를 수행하였기에, 본 연구에서 설정한 품질유지한계기간 및 소비기한을 보편적으로 사용하기에는 무리가 있다. 유통기한을 소비기한으로 변경하기 위해서는 다양한 제품에 대한 광범위한 품질 연구가 필요하다. 이 제도가 잘 갖춰진다면 올바른 음식물 섭취를 통해 음식물폐기물을 줄이는 데 도움이 될 수 있고, 소비자들은 안심하고 식품을 섭취할 수 있다.