• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.89-94
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• 2009

The purpose of this study is to provide a fundamental data for reducing energy consumption and greenhouse gas emission of detached houses by investigating the energy consumption characteristic of detached houses in Daegu. Although the ratio of the detached houses decreases, the detached houses are common dwelling form next to apartments. Nevertheless the study about the energy consumption of detached houses has been insufficient compared apartments. There is a necessity which will investigate the energy consumption characteristic of detached houses. Because that with the building quality which is various form is different from apartments. This study investigate construction and equipment conditions and analyzing effective factors on energy consumption of detached houses. And this study draw up the energy consumption unit and emission factors unit for greenhouse gas of detached houses. This study represent a basic report for energy consumption reduction and helps effective use of energy.

• Journal of The Korean Association For Science Education
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• v.37 no.5
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• pp.799-812
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• 2017

Energy as a powerful and unifying concept to understand natural world has been regarded as one of the key concepts of the science curricula in many countries. However, concerning learning and teaching of energy, various difficulties have been reported widely. This study aimed at analyzing and comparing science curricula of Korea, the U.S., England, and Singapore regarding energy to identify the potential issues for energy curriculum in the future. 2015 revised Korean science curriculum, Next Generation Science Standards of the U.S., Science programmes of study of England, and the Science syllabus of Singapore were compared based on six basic elements of the concept of energy: energy form, energy resource, energy transfer, energy transformation, energy conservation, and energy dissipation. Achievement criteria that include energy were extracted from all curricula and categorized into the six elements. The frequency and distribution of the six elements in the four curricula were compared in terms of school levels and disciplinary areas. Contents of six energy elements were also compared. Though all curricula emphasized energy as a key science concept, we found many differences in the degree of emphasis of basic ideas and specific contents and approaches. Korean curriculum is characterized by 1) high frequency concerning energy form among the elements of the concept of energy, 2) introducing energy forms of unclear meaning, which are not linked with other physical quantities, 3) emphasis on energy conversion in comparison of energy transfer, 4) focusing on mechanical energy conservation instead of more general energy conservation, and 5) absence of the concept of 'system' concerning energy. Issues for energy curriculum development were discussed.

• Geomechanics and Engineering
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• v.16 no.5
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• pp.503-512
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• 2018

Globally there is an increasing need to reduce the greenhouse gas emissions and increase the use of renewable sources of energy. The storage of solar thermal energy is a crucial aspect for implementing the solar energy for space heating in high latitudes, where solar insolation is high in summer and almost negligible in winter when the domestic heating demand is high. To use the solar heating during winter thermal energy storage is required. In this paper, equations representing the single U-tube heat exchanger are implemented in weak form edge elements in COMSOL Multiphysics(R) to speed up the calculation process for modelling of a borehole storage layout. Multiple borehole seasonal solar thermal energy storage scenarios are successfully simulated. After 5 years of operation, the most efficient simulated borehole pattern containing 168 borehole heat exchangers recovers 69% of the stored seasonal thermal energy and provides 971 MWh of thermal energy for heating in winter.

• International Journal of High-Rise Buildings
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• v.6 no.2
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• pp.177-185
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• 2017

This research suggests the most effective way for improving energy efficiency in tall buildings is a "fabric-first" approach. This involves optimizing the performance of the building form and envelope as a first priority, with additional technologies a secondary consideration. The paper explores a specific fabric-first energy standard known as "Passivhaus". Buildings that meet this standard typically use 75% less heating and cooling. The results show tall buildings have an intrinsic advantage in achieving Passivhaus performance, as compared to low-rise buildings, due to their compact form, minimizing heat loss. This means high-rises can meet Passivhaus energy standards with double-glazing and moderate levels of insulation, as compared to other typologies where triple-glazing and super-insulation are commonplace. However, the author also suggests that designers need to develop strategies to minimize overheating in Passivhaus high-rises, and reduce the quantity of glazing typical in high-rise residential buildings, to improve their energy efficiency.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.483-488
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• 1998

A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development.

• Journal of Korean Association for Spatial Structures
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• v.24 no.1
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• pp.65-72
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• 2024

This paper aims to advance our understanding of extensible beams with multiple cracks by presenting a crack energy and motion equation, and mathematically justifying the energy functions of axial and bending deformations caused by cracks. Utilizing an extended form of Hamilton's principle, we derive a normalized governing equation for the motion of the extensible beam, taking into account crack energy. To achieve a closed-form solution of the beam equation, we employ a simple approach that incorporates the crack's patching condition into the eigenvalue problem associated with the linear part of the governing equation. This methodology not only yields a valuable eigenmode function but also significantly enhances our understanding of the dynamics of cracked extensible beams. Furthermore, we derive a governing equation that is an ordinary differential equation concerning time, based on orthogonal eigenmodes. This research lays the foundation for further studies, including experimental validations, applications, and the study of damage estimation and detection in the presence of cracks.

• Journal of Power System Engineering
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• v.18 no.1
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• pp.45-50
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• 2014

This study focuses on the analysis of the cooling and heating load in accordance with apartment houses arrangement type using Ecotect Analysis. Korea have to reduce energy consumption part of building except in industry and transport because the rate of dependence on imports amounts to 94%, Apartment houses built in various forms in order to reduce energy are modelled in each window area ratio, shape, orientation, and climate through simulation. Through this study, we can analyze the cooling and heating load by form, window area ratio, orientation, and climate change and know the optimal elements by the form. In particular, although there have been done research on the window area ratio and the arrangement form, the research of the regional climate characteristics and the direction are hardly carried out. To supplement those problem, adding to seven direction and climatic element of southern region is characteristic(L Type, Y Type, - Type) of this study. The form of apartment houses built 10 years ago is modelled for simulation.

• KIEAE Journal
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• v.15 no.5
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• pp.113-118
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• 2015

Purpose: In Korea, buildings make up 20.5% (2012) of the gross national energy consumption, so they are a major target for greenhouse gas reduction. In particular, energy consumption in multihousing represents approximately 32.6% of the entire building sector. With improving energy performance being the focus, efforts are continuously being made to reinforce standards and systems in greenhouse gas reduction. This study investigated the current status of multihousing in Korea in terms of energy performance as described in the performance evaluation reports submitted (to an institution that specializes in reviewing the performance evaluation of green homes) based on the construction criteria and performance codes for green homes and examined if the evaluation criteria using related methodologies were appropriate. The results will provide helpful information for reviewing the future directions of operations and amendments to the systems. Method: The overall characteristics of the system were examined using the evaluation methodologies (and current state of revisions) of the performance codes for green homes and comparing them with similar systems. Also, the current state of application and energy performance (conducted according to the evaluation methodologies) were compared by the evaluation institution for multihousing neighborhoods that were assessed for five years from 2010 to 2014. Result: It has been confirmed that the performance codes for green homes are different from other similar systems in evaluating performances of multihousing in that they allow both quantitative and qualitative methods of evaluation, and they consider both energy and sustainability simultaneously in the evaluation. Furthermore, regarding the adoption rate of the forms for the two evaluation methods (Form 1 - quantitative and Form 2 - qualitative), the rate preferring Form 2 increased gradually in time to reach 55.3% in 2014. In analyzing the rate of overall energy reduction (submitted in Form 1) and the coefficient of thermal transmission for each part (submitted in Form 2), it was observed that the deviation between the performance submitted and the criteria decreased in line with the level of reinforcement.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.5
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• pp.455-459
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• 1997

Fifteen intact male Jamunapari goats, average body weight $22.0{\pm}1.18kg$ were divided into three groups of 5 animals in each to investigate the effects of feeding leucaena on energy retention and distribution of retained energy. Leucaena leaves and twigs provided 0%, 25% and 50% of CP in the rations of animals in $L_1$ (control), $L_2$ and $L_3$ groups, respectively. Energy balances were determined in an open circuit respiration chamber from gaseous exchange and nitrogen carbon balances. Energy retentions calculated from gaseous exchange data were 181.6, 190.0 and 172.8 kJ/kg $W^{0.75}/d$ and from carbon-nitrogen balances were 178.2, 199.5 and 171.1 kJ/kg $W^{0.75}/d$ in $L_1$, $L_2$ and $L_3$ groups, respectively. No significant difference was observed among the groups in both the methods. The retention of nitrogen and energy in the form of protein was similar in different treatment groups. Similarly, no significant effect was observed on energy retention in the form of fat and total energy retention due to incorporation of leucaena in the diets.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.92-97
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• 2006

Hull forms of a high speed small boat have been developed through numerical studies. A round bilge type hull form has been drived form a using chine hull form with HCAD, a hull form variation software. Wave resistance and the flow fields around the ships have been computed using well-known software, WAVIS. This software employs Rankine source method with non-linear tree surface condition as well as dry transom boundary conditions. The round bilge hull form showed better resistance performance than to the chine hull form for the whole speed range. However, considering the building and labor costs of the small shipyard, the chine hull form has been selected and its wave resistance characteristics has been improved by modifying the bow regions and applying the stem wedge. It is found that the effect of stem wedge is quite satisfactory to improve the resistance characteristics of high speed chine hull form.