• International Journal of Highway Engineering
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• v.19 no.5
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• pp.107-115
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• 2017

PURPOSES : The piezoelectric energy road analysis technology using a three-dimensional finite element method was developed to investigate pavement behaviors when piezoelectric energy harvesters and a new polyurethane surface layer were installed in field conditions. The main purpose of this study is to predict the long-term performance of the piezoelectric energy road through the proposed analytical steps. METHODS : To predict the stresses and strains of the piezoelectric energy road, the developed energy harvesters were embedded into the polyurethane surface layer (50 mm from the top surface). The typical type of triaxial dump truck loading was applied to the top of each energy harvester. In this paper, a general purpose finite element analysis program called ABAQUS was used and it was assumed that a harvester is installed in the cross section of a typical asphalt pavement structure. RESULTS : The maximum tensile stress of the polyurethane surface layer in the initial fatigue model occurred up to 0.035 MPa in the transverse direction when the truck tire load was loaded on the top of each harvester. The maximum tensile stresses were 0.025 MPa in the intermediate fatigue model and 0.013 MPa in the final fatigue model, which were 72% and 37% lower than that of the initial stage model, respectively. CONCLUSIONS : The main critical damage locations can be estimated between the base layer and the surface layer. If the crack propagates, bottom-up cracking from the base layer is the main cracking pattern where the tensile stress is higher than in other locations. It is also considered that the possibility of cracking in the top-down direction at the edge of energy harvester is more likely to occur because the material strength of the energy harvester is much higher and plays a role in the supporting points. In terms of long-term performance, all tensile stresses in the energy harvester and polyurethane layer are less than 1% of the maximum tensile strength and the possibility of fatigue damage was very low. Since the harvester is embedded in the surface layer of the polyurethane, which has higher tensile strength and toughness, it can assure a good, long-term performance.

• KIEAE Journal
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• v.13 no.2
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• pp.13-20
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• 2013

Today, the world energy consumption in buildings occupies more than 30%. In our country, the energy consumption in buildings also occupies 25% of the entire national energy consumption. With the increasing demand of energy saving in architectural fields, there is a more interest in low-energy construction. For these low-energy housings, our country is planning to apply the energy-saving design standards at the level of passive houses in 2017. However, there is still a limitation in energy saving only with the standards on the performance of envelope in buildings. This means that unless a building is airtight even though it was well-insulated, cooling and heating energy consumption will increase due to the infiltration and leakage. Therefore, this study aims to make a comparative analysis of airtight performance by conducting a blower door test on the housings applied with passive designs, analyze the reasons why most houses fall short of the airtightness standards, and complement the airtightness problems in the inadequate parts of the buildings in order to save building energy.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.196-201
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• 2011

The energy used in Korea is strongly dependent on that produced by foreign countries. Accordingly, saving energy is more important than ever, because of the rise of international oil prices and depletion of oil resources. The development of energy efficient buildings is required especially for public buildings in Korea. In this study, the energy use of public buildings is identify. Then, the analysis of energy usage through regional offices in Busan City offers energy performance for public buildings.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.191-198
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• 2009

Many Countries are making nationwide efforts to reduce the energy consumption which causes greenhouse gas emissions and global warming problems. Energy performance assessments and certification systems have been in force to save energy consumption of residential buildings, and are anticipated to have strong effects through the systems. Korean Building Energy Efficiency Rating System is in its early stages and is considered that the additional upgrade is needed for the accurate assessment. Thus, in this study, the assessment methods of the Building Energy Efficiency Rating System of Korea and the SAP2005 of UK were compared and energy requirements of an actual residential building were calculated with two assessment methods, respectively. The strengths and shortcomings of two systems were analyzed and a way of improving Korean system was suggested.

• Structural Engineering and Mechanics
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• v.48 no.5
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• pp.681-695
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• 2013

Performance-based seismic design allows a structure to develop inelastic response during earthquakes. This modern seismic design requires more clearly defined levels of inelastic response. The ultimate deformation of a structure without total collapse (target displacement) is used to obtain the inelastic deformation capacity (inelastic performance). The inelastic performance of a structure indicates its performance under excitation. In this study, a new energy-based method to obtain the target displacement for reinforced concrete frames under cyclic loading is proposed. Concrete structures were analyzed using nonlinear static (pushover) analysis and cyclic loading. Failure of structures under cyclic loading was controlled and the new method was tested to obtain target displacement. In this method, the capacity energy absorption of the structures for both pushover and cyclic analyses were considered to be equal. The results were compared with FEMA-356, which confirmed the accuracy of the proposed method.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.63-70
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• 2003

It is very important to improve the insulation performance of curtain wall anchoring unit since it is composed of materials with high thermal conductivity, such as aluminium, steel and so on. This study aims to evaluate the heating energy performance and economical efficiency of various alternatives which are different in position and material of insulation. As results, alternative of inserting the urethane washer & pad and coating the anchoring unit with urethane foam can improve the heating energy performance and L.C.C(Life Cycle Cost) by 6.33% and 0.95%, respectively, as compared with the existing case.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.73-79
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• 2006

The integration of PV modules into building facades or roof could raise PV module temperature that results in the reduction of electrical power generation. Lowering operating temperature of PV module is important in this respect, and PV module temperature should be considered more accurately, for building-integrated PV(BIPV) systems in predicting their performance. This paper describes a BIPV solar roof design and verifies its performance through experiment In relation to the effect of ventilation in space between PV module and roof surface. The results showed that the ventilation in the space had a positive effect in lowering the module temperature of the BIPV solar roof that enhanced the performance of its electricity generation.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.65-71
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• 2010

The hydrologic performance characteristics of small hydro power(SHP) sites located in four major river systems have been studied. The model, which can predict flow duration characteristic of stream, was developed to analyze the variation of inflow caused from rainfall condition. And another model to predict hydrologic performance for SHP plants is established. Monthly inflow data measured at Andong dam for 32 years were analyzed. The predicted results from the developed models in this study showed that the data were in good agreement with measured results of long term inflow at Andong dam. The results from hydrologic performance analysis for SHP sites located on five major river systems based on the models developed in this study show that the specific design flowrate and specific output of SHP site have large difference between the river systems.

• Journal of The Korea Institute of Healthcare Architecture
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• v.25 no.3
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• pp.7-14
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• 2019

Purpose: The purpose of this research is to find out week and strong aspects in LEED categories based on achieved scores earned by LEED-HC(Healthcare) v.2009. Methods: The LEED-HC scorecards of 88 healthcare projects are analyzed. The analysis are focused on relationship between achieved scores, LEED categories and achieved levels. This relationship was presented by graphs and charts. Results: 1) Compare to LEED-NC, in LEED-HC, sub-categories related to public health are added. The scores are added in Energy Atmosphere and Indoor Environmental Quality. 2) Achieve scores in Sustainable Site are high and one in Energy Atmosphere and Indoor Environmental Quality are low at all levels. 3) Scores which was lost in Energy Atmosphere are recovered in Material Resource and Sustainable Site in order to keep its level. 4) Since most of scores in Energy Atmosphere are under EAc1 Optimize energy performance sub-categories, it is important to achieve more score in Optimize Energy Performance Sub-Categories to gain a higher level. Even if LEED-HC has more score in Energy Atmosphere, this is a hard to achieve scores in that categories. It is important to review Energy Atmosphere categories and its points for improvement. Implications: This study will provide basic database in order to establish Korean green building rating system for hospital.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.371-378
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• 2001

To enhance seismic performance of a structure ATC-40 and FEMA-273 propose technical strategies such as increasing strength, altering stiffness, and reducing demand by employing base isolation and energy dissipation devices. Specifically the energy dissipation devices directly increase the ability of the structure to dampen earthquake response. However nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this study a simple and straightforward procedure is developed using effective damping ratio to obtain the required amount of viscoelastic dampers in order to meet given performance objectives. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the analysis results, earthquake demand and required damping ratio were reduced by installing viscoelastic dampers. The results also show that with the addition of the supplemental damping evaluted by the proposed method the performance of the model structures are well restrained within the target point.