• 대기
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• 제13권2호
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• pp.47-68
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• 2003

Recent advances in the studies on the interaction between Asian monsoon and ENSO cycle are reviewed in this paper. Through the recent studies, the East Asian summer monsoon circulation system and the East Asian climate system have proposed. Moreover, different responses of the (winter and summer) monsoon circulation and summer rainfall anomalies in East Asia to ENSO cycle during its different stages have been understood further. Recently, the studies on the dynamical effect of East Asian monsoon on the thermal variability of the tropical western Pacific and ENSO cycle have been greatly advanced. These studies demonstrated further that ENSO cycle originates from the tropical western Pacific, and pointed out that the dynamical effect of East Asian winter and summer monsoons on ENSO cycle may be through the atmospheric circulation and zonal wind anomalies over the tropical western Pacific, which can excite the oceanic Kelvin wave and Rossby waves in the equatorial Pacific. Besides, the scientific problems in the interaction between Asian monsoon and ENSO cycle, which should be studied further in the near future, are also pointed out in this paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.170-174
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• 2001

In this paper, CFD technique has been used at design stage to predict space air distribution in a cycle stadium with air circulation system. An air circulation flow of 0.67 rev./min was observed at computed results in the stadium space with and without air circulation system. Comparing the thermal comfort of the two models with or without air circulation system showed that the thermal environment in the former was superior in the latter. Energy savings could be achieved for the model with air circulation due to its lower air inflow temperature.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.103-108
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• 2005

For more accurately describing the durations of the light and the dark phases of micro-algal cells over the whole light-dark cycle, and probing into the relationship between the liquid circulation time or velocity, the aeration rate and cell density, a series of experiments was carried out in 10 cm light-path flat plate photobioreactors. The results indicated that the liquid flow in the flat plate photobioreactor could be described by liquid dynamic equations, and a high biomass output, higher content and productivity of arachidonic acid, $70.10\;gm^{-2}d^{-1},\;9.62\%$ and 510.3 mg/L, respectively, were obtained under the optimal culture conditions.

• 순환기질환의공학회:학술대회논문집
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• 순환기질환의공학회 2004년도 제4회 학술대회 초록집
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• pp.26-27
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• 2004

• KIEAE Journal
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• 제15권4호
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• pp.37-43
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• 2015

Purpose : The study applied control strategy to reduce through optimal control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. The study has the purpose to review validity of control on variable speed as ESMs(Energy Saving Measures) and establish the control technology on variable speed pump. The study performed reduction analysis of building energy and economic evaluation of pump through energy effectiveness control strategy of HVAC system. Method: The study sought possible reduction through energy control strategy which can provide proper flow fitting to building load by applying control on variable speed pump. The study applied control strategy to reduce through pressure differential set-point control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. Result : The results showed that about 16-35% of pump energy could be saved by using these optimal control strategies. In the result of analysis on 10 years life cycle cost of analysis on payback period of initial investment pump, variable speed pump control showed 5.1 years.

• 한국환경과학회지
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• 제29권4호
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• pp.339-349
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• 2020

This study aims to identify participating resident awareness of the improvements to forest carbon cycle villages created by the Korea Forest Service by introducing a system for district heating basedon forest biomass in mountainous areas. Hwacheon Forest Carbon Circulation village was established in Paroho-neureup village in Yuchon-ri, Hwacheon-gun between 2011 and 2013. However, its operation has not been smooth due to the increasing number of households rapidly leaving the district heating system. This study surveyed 76 households that participated in the district heating system using forest biomass in the early stages of the project. This includes households participating in the district heating system(participating households) and households not currently participating in the district heating system(withdrawal households) from September 2019. Surveys focused on the process of participating in forest carbon cycle village projects, and satisfaction in local heating and policy requirements. Of the 67 households, excepting those not allowed to participate in the survey due to death or having moved elsewhere, 36 households participated and 31 households the were in the process of leaving the village were also included. As a result, there was a significant difference between participating and exiting households in the motivation and satisfaction level of district heating. The results of this study are expects to reflect the importance of awareness of residents in the operation of the forest carbon cycle village. This will be utilized as an important dataset for improvement as a means to promote the re-entry if outgoing households. It will also help set the direction of the forest town revitalization project, utilizing forest biomass in the future.

• 한국가스학회지
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• 제22권4호
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• pp.63-73
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• 2018

잉여전력 등을 활용한 에너지저장시스템 분야에 기술에 관심이 집중되고 혁신적인 기술진보가 이루어지고 있다. 다양한 에너지저장시스템 분야 중 가스액화 방식을 활용한 액화공기에너지저장 시스템은 상당히 성숙된 기술로 알려져 있고, 높은 단위 에너지 밀도와 설치에 따른 지형적 제약이 거의 없으며 수명이 긴 저장 시스템이라는 많은 장점에도 불구하고, 단일공정 (공기액화-재기화 사이클)의 낮은 사이클 효율로 인해 상업화에 한계가 있었다. 본 연구에서는 낮은 사이클 효율을 개선하고자 2종류의 냉매(R-600a 와 메탄올)을 이용한 냉매사이클을 공기 액화 공정에 활용하여 사이클 효율을 향상시키고, 공기 압축시 발생하는 압축열을 열매체유 순환 사이클에 이용하여 이를 액화공기 재기화 공정의 터빈 입구 온도를 높이는데 활용하여 전력생산량을 추가적으로 증가시킴으로써 사이클 효율을 획기적으로 향상시킬 수 있는 가능성을 Aspen HYSYS 공정 모사 프로그램을 활용하여 확인하였다.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 1996년도 정기학술강연회 발표논문 초록집
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• pp.7-9
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• 1996

A simple two-and -half-layer model is used to study the circulation of South China Sea( SCS ). The model is coming from the reduced gravity model of Hurbult and Thompson, with the assumption of rigid surface. It shows there is no distinct branch of the Kuroshio into the SCS. Both the upper and lower pycnocline height anomaly show that the main feature of the circulation of SCS is a cyclone, which is generated by the transportion of the vorticity from the Kuroshio. Aftr generated, the cyclone moves westward due to the beta effect, then dissipates near the west boundary due to the viscosity. After an old one dissipates, a new one appears again. The life cycle of the cyclone is about 160 days.

• 지식경영연구
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• 제3권2호
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• pp.31-48
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• 2002

Recent trend of business is characterized by a recognition of importance of knowledge asset. Especially, this phenomenon is receiving more momentum as our society goes digital rapidly. However, most of literature on knowledge management is based on knowledge circulation from the corporate point of view, not from individual viewpoint. In this regard, this paper is concerned with proposing knowledge circulation process and its efficiency from the individual perspective. We adopted structural equation model or SEM to prove the statistical validity of our research framework. Eight hypotheses were built and tested empirically, leading to the fact that the knowledge utilization and sharing of individuals have a positive impact on the knowledge management efficiency.

• Current Research on Agriculture and Life Sciences
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• 제30권2호
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• pp.97-104
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• 2012

Over the last century, drainage systems have become an integral component of agriculture. Climate observations and experiments using General circulation models suggest an intensification of the hydrologic cycle due to climate change. This study presents hydrologic simulations assessing the potential impact of climate change on subsurface drainage in Daegu, Republic of Korea. Historical and Long Ashton Research Station weather generator perturbed future climate data from 15 general circulation models for a field in Daegu were ran into a water management simulation model, DRAINMOD. The trends and variability in rainfall and Soil Excess Water ($SEW_{30}$) were assessed from 1960 to 2100. Rainfall amount and intensity were predicted to increase in the future. The predicted annual subsurface drainage flow varied from -35 to 40 % of the baseline value while the $SEW_{30}$ varied from -50 to 100%. The expected increases in subsurface drainage outflow require that more attention be given to soil and water conservation practices.