• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.29-35
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• 2007

In accordance with Madrid and Kyoto Protocols, a 10kw wind turbine installed about 625m away from the King Sejong Station in the Antarctica has been in operation successfully. The current location of the wind turbine has different geographic surroundings from the previous candidate site considered in 2005 and that makes re-evaluation of wind resource at the current site including geographic effects necessary. Especially, strong wind flow derived by steep and complex terrain is dominant in the Antarctica so that computational flow analysis is required. The wind rose measured at the previous and current installation location are identical with strong meteorological correlation but prevailing directions of wind power density are different because of local wind acceleration due to complex terrain. Numerical analysis explains which effects brings this discordance between the two sites, and a design guideline required for additional wind turbine installation has been secured.

• 천문학회보
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• 제37권1호
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• pp.69.1-69.1
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• 2012

Monte Carlo codes for extensive air shower (EAS) simulate the development of EASs initiated in the Earth's atmosphere by ultra-high energy cosmic rays (UHECRs) with energy exceeding - $10^{18}$ eV. Here, we compare EAS simulations with two different codes, CORSIKA and COSMOS, presenting quantities including the longitudinal distribution of particles, depth of shower maximum, kinetic energy distribution of particle at the ground, and calorimetric energy. In addition, the lateral distribution of local energy density far from the EAS core has been known as an important quantity to estimate the energy of UHECRs. We also present the lateral distribution function obtained from GEANT4 simulations for detector response.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.269-269
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• 2013

Usingvan der Waals (vdW) energy-corrected density-functional theory without or with self-consistent screening (SCS) effects, we calculate the adsorption energy of acetylene, ethylene and benzene on Si(100). We find that vdW interactions without SCS effects increase the adsorption energy by 0.23, 0.30, and 0.64 eV for adsorbed $C_2H_2$, $C_2H_4$, and $C_6H_6$ on Si(100), respectively. However, if SCS effects are included, this increase of the adsorption energy is reduced as 0.19, 0.24, and 0.54 eV for the three adsorption systems, respectively. The resulting adsorption energy for each system is between the values computed using the local-density approximation and the generalized-gradient approximation.

• Asian Journal of Atmospheric Environment
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• 제1권1호
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• pp.14-18
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• 2007

The Korean government enacted the "Special Law for Improving Air Quality of Metropolitan Area" in 2003. According to this plan, Korean government plan to lower the concentrations of $PM_{10}$ and $NO_x$ to $40{\mu}g/m^3$ and 22 ppb, respectively, by 2014. In this study, we analyze emission reduction strategies to lower their concentration. Emission reduction for the supply of mass energy and regenerative energy are compared with several scenarios. According to the results, 713 t/y of $NO_x$ and 165 t/y of $PM_{10}$ will be reduced by enhancing the number of households supplied by local heating and air conditioning. And also 5 t/y of $PM_{10}$ and 312 t/y of $NO_x$ will be reduced by replacing conventional energy with solar energy by 2014.

• 대한기계학회논문집A
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• 제30권12호
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• pp.1603-1610
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• 2006

In this paper compressive characteristics of composite egg-box panels were investigated and energy absorption was calculated from the nominal stress-strain relations obtained by the compressive tests. Several different stacking sequences and number of plies were introduced for investigation of static compression characteristics and the energy absorption rates of composite egg-box panels. The compressive stress-strain relation and energy absorption of various composite egg-box panels were compared with those of aluminium egg-box panels. From the test results it was found that the fracture behavior of composite egg-box panel was affected by stacking angle causing different local deformation, during lay-up and draping processes and types of prepreg; that is, plain weave carbon/epoxy and 4-harness satin glass/epoxy. The energy absorption capacity of composite egg-box panels were proved to be higher than that of aluminium egg-box panels with low mass.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권1호
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• pp.80-84
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• 2010

한 소스로부터 다수의 싱크로의 데이터 멀티캐스팅은 통신 비용 절약 뿐 아니라 효율적인 에너지의 사용을 위해 이루어진다. 무선 센서 네트워크에서, 지금까지의 멀티캐스팅 위한 방안들은 대부분 하나의 소스와 다수의 고정적인 싱크들 사이의 최적화된 멀티캐스트 트리로 만들어진다. 하지만 전쟁 지역에서의 적군 감지 시스템, 재난지역 구조 시스템 등의 실질적인 응용들에서, 싱크는 자신의 미션을 수행하기 위해 이동성을 가지고 센서 네트워크를 돌아다닐 것이다. 불행히도 싱크의 이동성은 전체 멀티캐스트 트리의 빈번한 재구성을 초래하고 이것은 제한된 배터리를 가진 센서들의 에너지 고갈을 야기시킨다. 그러므로, 우리는 지역적인 멀티캐스트 트리의 재구성을 통해 다수의 이동 싱크를 지원하는 에너지 효율적인 멀티캐스트 프로토콜을 제안한다. 또한 시뮬레이션을 통해 제안된 방안이 기존 연구들 보다 에너지 자원 관리 측면에서 더 효과적임을 보인다.

• 한국농공학회논문집
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• 제50권3호
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• pp.105-112
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• 2008

Solar energy, which is one of renewable energy, would be the most useful resources that can be applied to making energy recycling villages without using fossil energy. This study analyzed energy potential on solar energy considering weather condition in three traditional villages and compared with energy consumption surveyed. A photovoltaic system having 3.0kWp capacity of unit module can generate 182.5%, 96.1% and 170.9% of the yearly mean consumption of electric power in Makhyun, Boojang, and Soso, respectively. A flat-plate solar collector having $2.64m^2$ area of unit module can generate warm water of $142{\ell}$/day, $89{\ell}$/day, and $173{\ell}$/day, respectively in three study villages. In Makhyun and Soso, photovoltaic power and warm water produced by solar energy were sufficient to supply required amount of electric power and warm water. However, both electric power and warm water produced by unit solar module were not sufficient in Boojang area, and so it is required to increase the module area by more than 50%. According to the results of this study, the appropriate combination of energy resources can be applied to rural green-village planning if the characteristic of energy potential for each local area is considered.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.655-663
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• 2016

최근, 전 세계적으로 온실 가스 증가에 따른 기후 변화에 대한 문제가 논의되고 있다. 그중, 건축물에서의 에너지 소비량은 전체 에너지 소비량의 40%까지 증가할 것으로 예상된다. 따라서 건축물에서의 에너지 소비량 절감에 대한 노력이 필요한 실정이다. 본 연구에서는, 건물에너지 절감에 효과적으로 기여하는 재료 중 하나인 목재를 이용하여, 목질 제품 구성에 따른 중부지방과 남부지방의 난방에너지 요구량에 대하여 시뮬레이션을 통해 분석하였다. 시뮬레이션 도구는 미국 에너지부(Department of Energy)가 BLAST와 DOE-2의 장점을 결합해 만든 동적 에너지 해석 엔진인 EnergyPlus를 이용하였다. EnergyPlus는 다양한 건물 및 HVAC 시스템 구성요소(Object)에 대한 입력항목(Field)을 가지고 있으며, 특히 건물, 공조시스템, 열원기기 사이의 피드백을 통해 통합된 동시계산을 수행하며, ASHRAE Standard 140-2007 표준에 따라 상용 프로그램 간의 비교를 통해 검증된 프로그램이다. 시뮬레이션을 위한 기상데이터는 EnergyPlus에서 제공하는 IWEC 인천 지역과 광주 지역의 epw 형식 기상데이터를 이용하였다. 대상 모델은 한국농어촌공사에서 제시한 2012년 농 어촌주택 표준설계도면 중 '농림-12-26-가' 유형을 이용하였으며 총 10개의 실로 구성되어 있다. 시뮬레이션 분석 결과, 중부지방과 남부지방 별 목질 제품의 적용 범위를 실내마감재, 실외마감재, 창호, 목구조로 단계적으로 변경해 지역에 따라 각각 16 Case의 시뮬레이션을 수행한 결과 실내외의 마감재로 목재를 사용한 것만으로도 에너지 성능이 향상된 것을 확인할 수 있었다.

• 대한기계학회논문집A
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• 제21권10호
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• pp.1598-1608
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• 1997

Based on the application of te theory of conjugate approximations and the Loubignac's iterative method in a local region, a method to improve the stress filed in a displacement-formulated finite element solution has been proposed. The validity of the proposed method has been tested through two examples : a thick cylinder under internal pressure loading and an infinite plate with a central circular hole subjected to uniaxial tension. As a result of analysis of the examples, it was found that the stress field obtained for the local region model by the proposed method approximates well for the whole domain model. In addition, it was found that because of a significant decrease in the computing time to obtain the improved stress field, the proposed method is efficient and useful for the detailed stress analysis in local regions.

• Nuclear Engineering and Technology
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• 제38권2호
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• pp.139-146
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• 2006

An experimental study was performed to evaluate the effects of surface coating and an enhanced insulation structure on the downward facing boiling process and the critical heat flux on the outer surface of a hemispherical vessel. Steady-state boiling tests were conducted in the Subscale Boundary Layer Boiling (SBLB) facility using an enhanced vessel/insulation design for the cases with and without vessel coatings. Based on the boiling data, CHF correlations were obtained for both plain and coated vessels. It was found that the nucleate boiling rates and the local CHF limits for the case with micro-porous layer coating were consistently higher than those values for a plain vessel at the same angular location. The enhancement in the local CHF limits and nucleate boiling rates was mainly due to the micro-porous layer coating that increased the local liquid supply rate toward the vaporization sites on the vessel surface. For the case with thermal insulation, the local CHF limit tended to increase from the bottom center at first, then decrease toward the minimum gap location, and finally increase toward the equator. This non-monotonic behavior, which differed significantly from the case without thermal insulation, was evidently due to the local variation of the two-phase motions in the annular channel between the test vessel and the insulation structure.