• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.916-918
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• 1995

This paper has researched designing methods and characteristics of the indoor two-way CATV amplifier to amplify the weak signals and to separate the signals in the forward and the reverse channels in the cable system. It consists of diplex filters, equalizers, attenuators and amplifier modules. With the experimental results for frequency response, gain and slope controls, noise figures, return losses, distortion characteristics, we concluded that the operating capabilities of the amplifier developed in this research satisfy the design conditions.

• Korean Journal of Construction Engineering and Management
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• v.21 no.4
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• pp.100-107
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• 2020

In this paper, a study was conducted on the method of establishing the master plan standard for rational decision-making about utility tunnel construction in the existing urban. In the previous study, the optimal route was selected by the feasibility assessment. However, in order to increase the objectivity of the installation conditions of the utility tunnel in the master plan standard, comprehensive evaluation of the results by feasibility and economics analysis calculates the overall ranking for all sections analyzed. In addition, based on the results of the comprehensive evaluation, a method for establishing a mid·long term investment plan was introduced after reviewing the project to be conducted in the region. Additionally, in order to review the establishment of the standard suggested in the paper, an analysis was conducted by applying the master plan procedure to the northwestern urban zone of seoul.

• Architectural research
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• v.11 no.2
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• pp.27-34
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• 2009

The purpose of this study is to investigate the problem of crack repair materials and methods in existing concrete structure and to propose the effective injection method on crack repair by packer type. The result of this study is as follows. It is investigated that the crack width in the inner matrix of concrete structure is decreased about 30-40% than that in the surface of the concrete structure. Also it is showed that the possibility which could be monolithic with injection part became higher if the injection part is installed near to surface of concrete on the punching method to vertical direction against crack area. The injection of repair material can be poured smoothly under about $10N/mm^2$ pressure on the condition that cracks are monolithic with injection part without dust by drill. The method which is effective injection for a repair material is the punching method in compliance with coredrill. But, the research continuously is necessary about minimum injection pressure.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.1
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• pp.43-51
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• 2013

In this paper, analytical models for reinforced concrete shear wall systems designed based on Korean Building Code (KBC2009) are proposed, which have special and semi-special seismic details and are compared with experimental results for a verification of analytical models. In addition, semi-special seismic details aimed to improve constructability and enhance economic efficiency were proposed and evaluated. The analytical models were performed based on nonlinear static and dynamic analysis. Through the nonlinear analyses, two seismic details showed the similar seismic behavior from the cyclic test and the analytical models for the two different seismic details represented the behavior in terms of the initial stiffness, maximum strength and strength degradation. And newly proposed seismic details(semi-special) provided with similar hysterestic behavior as well as the maximum drift.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.4
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• pp.181-191
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• 2014

This research presents the nonlinear analysis model for reinforced concrete shear wall systems with special boundary elements as proposed by the Korean Building Code (KBC, 2009). In order to verify the analysis model, analytical results were compared with the experimental results obtained from previous studies. Established analytical model was used to perform nonlinear static and dynamic analyses. Analytical results showed that the semi-special shear wall improved significantly the performance in terms of ductility and energy dissipation as expected based on previous test results. Furthermore, nonlinear incremental dynamic analysis was performed using 20 ground motions. Based on computer analytical results, the ordinary shear wall, special shear wall and newly proposed semi-special shear wall systems were evaluated based on the methods in FEMA P965. The results based on the probabilistic approaches accounting for inherent uncertainties showed that the semi-special shear wall systems provide a high capacity/demand (ACMR) ratio owing to their details, which provide enough capacity to sustain large inelastic deformations.

• KIEAE Journal
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• v.14 no.2
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• pp.61-68
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• 2014

This study aims at proposing a sound and sustainable development direction of an residential environment by analyzing testimonies of residents who lived in Park Hill flats or their surround at Sheffield City in the United Kingdom. The results are obtained through the analysis on a residential environment of Park Hill flats, opinions of the residents on its refurbishment, and effects of the building on the residential environment. The block of Park Hill flats was a community with a strong unity and solidarity, but that became increasingly a slum by the decline of the physical and social environment since the 1980s. In particular, it was identified that the deterioration of the social environment than that of the physical environment was a major cause of the decline. Nevertheless, it was found that "streets in the sky", the concept applied in Park Hill, played a key role in activating the community in the apartment complex. However, that street system in the complex has caused noise, poor security, and invasion of privacy. If such problems are solved, the streets in the sky will be a meaningful alternative for community activation and then ensuring sustainability in Korean residential environments that lost the function of the community.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1068-1074
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• 2009

The progress is widely used as a critical index for successful construction project management. In spite of the importance of progress measurement, the excessive management effort to collect and maintain detailed data has been highlighted as a major barrier to measurement of highly accurate progress. In order to reduce the required workload and to enhance accuracy, several researches have been conducted. These researches can be categorized into two groups. First group focuses on automated data collection utilizing advanced technologies only for limited construction tasks. The second group is a research area where the standard progress measurement methodologies encompassing entire construction tasks are investigated. Topics include the adjusting the level of details, standardizing work processes, and applying flexible WBS. However, the techniques for automated data collection are not fully investigated yet in the second group. Combining these two research areas can provide a solution for more effective progress management in terms of enhancing accuracy and optimizing workload. However, there has been no comprehensive research addressing these two research groups in an integrated manner. In this context, the purpose of this paper is to propose a methodology that identifies the most suitable measurement method and data acquisition technology (e.g., GPS, RFID, etc.) for entire construction tasks of a project. The proposed methodology in this paper will be able to facilitate the selection process of data acquisition technologies for entire construction tasks of a project and to support the overall enhancement of automated progress management.

• Journal of Environmental Science International
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• v.17 no.3
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• pp.343-350
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• 2008

The fate of two cyclic ethers, THF(Tetrahydrofuran) and 1,4-Dioxane, in conventional biological wastewater treatment plants was investigated using sequential activated sludge process. Removal efficiency of THF were about 86% in average, which was greater than that of 1,4-Dioxane, 30%. However, it was not clear whether the removal of cyclic ethers in biological system was caused by microbial activity or not. Thus treatability tests were conducted by batch experiments. The effects of mixing, aeration and the addition of activated sludge on the removal of cyclic ethers were investigated in batch experiments. THF was totally removed by mixing and aeration in 24 hours while removal ratio of 1,4-Dioxane was at most 30% for the same period. This results could be ascribed to the differences in Henry's law constants between the two chemicals. In addition, biological degradation including biosorption was not obviously observed in these batch tests.

• Korean Institute of Interior Design Journal
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• v.13 no.5
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• pp.48-55
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• 2004

The remodeling of apartment that improves the improves the life level is going to be in the market because of lots of old apartment buildings. Until now, the research of remodeling is mainly restricted to the laws and financial funding, however, the needs in the trend of remodeling. This research, first, through the examples of remodeling in the country, this study draws remodeling factors that can be applied. Secondly, this study targets the study of remodeling to apartments and analyzes the type of housings made by the Korea National Housing Corporation. Thirdly the study analyzes the features that appear in housing units and draws out factors of remodeling This research's result Is arranged as follows. \circled1Need Remodeling thorough study of space expanded, grant between artificer and active performance improvement direction such as building equipment expansion along with Remodeling concept of unit repair. \circled2When apartments are newly built, systematic construction is necessary that considers future efficiency improvement from the design stage. \circled3This study, which applied the characteristic factors appearing after the 1990s to remodeling factors, show that they can be applied when remodeling the worn out wall-slab type apartments.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.86-94
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• 2023

This study was conducted with the purpose of preparing an alternative to improving the safety of civil pressure regulators installed instead of gas governors to supply city gas to apartment houses. First, problems were derived and solutions were presented by investigating the safety standards and installation status of domestic pressure regulators. In addition, using the DNV Phast-Safeti program, a quantitative risk assessment solution, risks such as gas leakage contained in pressure regulators installed in apartment houses and surrounding gas facilities were evaluated in terms of individual risks and societal risks, and measures were derived to reduce the risks in the installation and management of the pressure regulators.