• Steel and Composite Structures
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• v.43 no.2
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• pp.153-164
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• 2022

In this study, a series of cyclic loading tests were performed on viscoelastic dampers (VED) composed of viscoelastic polymer composite material and thin steel plates to observe the variation of the mechanical properties under different loading conditions. A mathematical model was developed based on the Kelvin-Voigt and Bouc-Wen models to formulate the nonlinear force-displacement relationship of the viscoelastic damper. The accuracy of the proposed mathematical model was verified using the data obtained from the tests. The mathematical model was applied to analyze a reinforced concrete framed structure retrofitted with viscoelastic dampers. Nonlinear dynamic analysis results showed that the average maximum inter-story drift ratios of the retrofitted structure met the target limit state after installing the VED. In addition, both the maximum and residual displacements were significantly reduced after the installation of the VED.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.12
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• pp.1090-1097
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• 2000

Predicting building energy use can be useful to evaluate its energy performance. This study proposed empirical approach for predicting building energy use with regression analysis. For the empirical analysis, simple regression models were developed based on the historical energy consumption data as a function of daily outside temperature, the predicting equations were derived for different operational modes and day types, then the equations were applied for predicting energy use in a building. BY selecting a real building as a case study, the feasibilities of the empirical approach for predicting building energy use were examined. The results showed that empirical approach with regression analysis was fairly reliable by demonstrating prediction accuracy of $pm10%$ compared with the actual energy consumption data. It was also verified that the prediction by regression models could be simple and fairly accurate. Thus, it is anticipated that the empirical approach will be useful and reliable tool for many purposes: retrofit savings analysis by estimating energy usage in an existing building or the diagnosis of the building operational problems with real time analysis.

• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.11-18
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• 2016

Under the Renewable Heat Obligation (RHO) public buildings in the Republic of Korea larger than $10,000m^2$ must achieve an 11% overall reduction to thermal energy consumption. Well intended solutions have been proposed. However, not all option is evaluated on the same basis, potentially resulting in incomplete or sub-optimal solutions. What's more once projects are implemented, there are inconsistencies in the methods used to measure and evaluate operating performance of the post-retrofit case. The RETScreen decision tools and methodology can be used by decision makers, policy developers, architects, engineers and community leaders to evaluate and select the most effective solutions for Korea's RHO needs.

• KIEAE Journal
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• v.12 no.6
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• pp.63-68
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• 2012

The aim of this study is to evaluate current policies and suggest the way of overcome financial impediments to the energy efficiency function of residential buildings. Based on this analysis the paper enumerates policy recommendations for enhancing how energy efficiency is addressed in building codes and other policies for residential buildings. For achieving this goal, this study conducts the cost-benefit analysis to measure total energy savings and associated total cost. The results of study shows that the cost is greater than the benefit from 1st to 4th year but the benefit will be greater than the cost for the rest of the year. In addition, this study designs a financial support method and an implementation mechanism. Investment from the capital market will take place with the government's interest subsidy. Home retrofit will be undertaken with low interest rate with 2.5% and the return will be paid by a monthly energy bill. The results of this study provides some useful insights for the policy design, including the importance of developing information tools for providing appropriate information to households.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.149-161
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• 2012

The use of seismic energy-dissipative devices for passive control is increasing exponentially in the recent years for both new and existing buildings. Use of these devices started in and has been somewhat limited to developed countries. One of the current challenges is to promote the use of seismic dampers in earthquake-prone developing countries by lowering the cost of the devices. This paper proposed a new type of seismic damper based on yielding of a cantilever type metallic element for seismic retrofit of existing and new building structures. The hysteretic behavior and energy dissipation capacity of the proposed damper was investigated using component tests under cyclic loads. The experimental results indicated that the damping device had stable restoring force characteristics and a high energy dissipation capacity. Based on these results, a simple hysteretic model for predicting the load-displacement curve of the seismic damper was proposed.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.61-68
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• 2021

The application of renewable energies such as wind and solar has become an inevitable choice for many countries in order to achieve the reduction of greenhouse gases and healthy economic development. However, due to the intermittent characteristics of renewable energy, the issue with integrating a larger proportion of renewable energy into the grid becomes more prominent. A complex energy system, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply. Compared with the power system, control and optimization of the complex energy system become more difficult in terms of modeling, operation, and planning. The main purpose of the complex energy system retrofit for samado island with microgrid system is to coordinate the operation with various distributed energy resources, energy storage systems, and power grids to ensure its reliability, while reducing the operating costs and achieving the optimal economic benefits. This paper suggests the improved complex energy system of samado island with optimal microgrid system. The results of test operation show about 12% lower SOC variation band of ESS, elimination of operation limit in PV and reduction of operation time in diesel generator.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.5
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• pp.575-582
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• 1988

This paper presents an energy analysis on the VAV system of 10-story building in Seoul using DOE-2 program and Modified Bin Method. The use of VAV system is an excellent means of saving energy in new buildings and/or retrofit. The fan control techniques considered are cycling, discharge dampers, inlet vanes, and motor speed control. The monthly and annual energy consumption is calculated for fan control techniques, components, and chiller types. The results of annual fan electricity use are compared using DOE-2 and Modified Bin Method, and show fairly good agreement. In addition, factors affecting energy consumption are also described.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.64-72
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• 2022

In this study, in order to confirm the seismic performance of reinforced concrete frames retrofitted with Wall Friction Damper(WFD), the test was conducted by setting two-story Reinforced concrete frames (reference specimen, OMF-N and specimen retrofitted with internal H-shaped steel frame and WFD, OMF-ALL(H)) as main variables. The WFD Seismic Retrofit Method is a mixture of strength improvement and energy dissipation methods. To prevent the pre-destruction of existing structure by friction force before sufficient energy dissipation of WFD, the internal H-shaped steel frame and chemical anchor that penetrates the side of the beam were used to install WFD. According to the test results, the OMF-N specimen showed an brittle failure pattern caused by the shear force of the R/C column after the maximum strength was expressed. The OMF-ALL(H) specimen showed that the reduction of pinching effect and the failure of the RC column occurred. Also, the maximum strength, cumulative energy dissipation and ductility of OMF-ALL(H) increased 3.01 times, 7.2 times and 1.72 times for OMF-N. As a results, test results revealed that the WFD Seismic Retrofit Method installed on Reinforced concrete structure improves the seismic performance and the strengthening effect is valid.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.616-622
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• 2012

Earthquake damage of viaduct bridge of railroad may give rise to social loss due to transport restrictions greater than cost of structural recovery. Therefore, viaduct bridge of railroad should have ensure adequate seismic performance. But, results of seismic performance evaluation, many of seismic retrofit was required. In this study, five scale models of columns were made and four of them were reinforced by HT-A(HyperTex & perforate Aluminum) which is improved than existing method. Testing the columns by constant axial load and cyclic lateral displacements, seismic performance of columns has been verified from the result of evaluating the stiffness, ductility and energy dissipation capacity.

• Journal of Construction Engineering and Project Management
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• v.5 no.4
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• pp.16-22
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• 2015

This paper presents an automated computer vision-based system to update BIM data by leveraging multi-modal visual data collected from existing buildings under inspection. Currently, visual inspections are conducted for building envelopes or mechanical systems, and auditors analyze energy-related contextual information to examine if their performance is maintained as expected by the design. By translating 3D surface thermal profiles into energy performance metrics such as actual R-values at point-level and by mapping such properties to the associated BIM elements using XML Document Object Model (DOM), the proposed method shortens the energy performance modeling gap between the architectural information in the as-designed BIM and the as-is building condition, which improve the reliability of building energy analysis. Several case studies were conducted to experimentally evaluate their impact on BIM-based energy analysis to calculate energy load. The experimental results on existing buildings show that (1) the point-level thermography-based thermal resistance measurement can be automatically matched with the associated BIM elements; and (2) their corresponding thermal properties are automatically updated in gbXML schema. This paper provides practitioners with insight to uncover the fundamentals of how multi-modal visual data can be used to improve the accuracy of building energy modeling for retrofit analysis. Open research challenges and lessons learned from real-world case studies are discussed in detail.