• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.37.1-37.1
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• 2021

For the first time in Korea, we are developing technology for gravitational wave (GW) detectors as a major R&D program. Our main research target is quantum noise reduction technology which can enhance the sensitivity of a GW detector beyond its limit by classical physics. Technology of generating squeezed vacuum state of light (SQZ) can suppress quantum noise (shot noise at higher frequencies and radiation pressure noise at lower frequencies) of laser interferometer type GW detectors. Squeezing technology has recently started being used for GW detectors and becoming necessary and key components. Our ultimate goal is to participate and make contribution to international collaborations for upgrade of existing GW detectors and construction of next generation GW detectors. This presentation will summarize our results in 2020 and plan for the upcoming years. Technical details will be presented in other family talks.

• Steel and Composite Structures
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• v.51 no.5
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• pp.499-507
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• 2024

The paper delves into an emerging paradigm shift in architectural design, focusing on the development of a cutting-edge methodological framework for the artistic enhancement of nanocomposite brick facades in building construction. This innovative approach represents a fusion of art and science, harnessing the potential of advanced nanotechnology to redefine the aesthetic and functional properties of building exteriors. Central to this new methodology is the integration of state-of-the-art materials and fabrication techniques, aimed at not only elevating the visual appeal of architectural structures but also enhancing their structural robustness and environmental sustainability. By leveraging the unique characteristics of nanocomposite materials, the proposed method opens up new possibilities for pushing the boundaries of traditional brick facade design. Through a meticulous exploration of the intricacies involved in implementing this novel approach, the paper elucidates the transformative impact it can have on the architectural landscape. By marrying creativity with technical precision, the method environment for art design of nanocomposite brick facades promises to usher in a new era of sustainable, visually captivating, and structurally resilient building facades that are poised to redefine the very essence of architectural aesthetics.

• Steel and Composite Structures
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• v.21 no.2
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• pp.343-356
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• 2016

As the common cast-in-place construction works fails to meet the enormous construction demand under rapid economic growth, the development of prefabricated structure instead becomes increasingly promising in China. For the prefabricated structure, its load carrying connection joint play a key role in maintaining the structural integrity. Therefore, a novel end plate bolt connecting joint between fully prefabricated pre-stressed concrete beam and high-strength reinforcement-confined concrete column was proposed. Under action of low cycle repeated horizontal loadings, comparative tests are conducted on 6 prefabricated pre-stressed intermediate joint specimens and 1 cast-in-place joint specimen to obtain the specimen failure modes, hysteresis curves, skeleton curves, ductility factor, stiffness degradation and energy dissipation capacity and other seismic indicators, and the seismic characteristics of the new-type prefabricated beam-column connecting joint are determined. The test results show that all the specimens for end plate bolt connecting joint between fully prefabricated pre-stressed concrete beam and high-strength reinforcement-confined concrete column have realized the design objectives of strong column weak beam. The hysteretic curves for specimens are good, indicating desirable ductility and energy dissipation capacity and seismic performances, and the research results provide theoretical basis and technical support for the promotion and application of prefabricated assembly frames in the earthquake zone.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.143-151
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• 2020

Recently, research on self-healing concrete has been actively conducted, and various methods have been attempted for use in the maintenance of structures. However, contrary to the technical development of self-healing concrete, the method for evaluating the performance is insufficient. Although surface observation and permeability experiments are widely used to observe the healing of cracks, microscopic observation of surface may be insufficient to assess the overall performance. Also, permeation experiments should consider the losses caused by the dissolution of self-healed product and viscosity of water. Although a gas diffusion experiment have been proposed to overcome the shortcomings of these two test methods, verification has not been made on specimens with actual healing. Therefore, in this study, gas diffusion experiments were performed on the mortar specimens that had healed, and the adequacy of self-healing evaluation by the gas diffusion experiment was verified.

• Smart Structures and Systems
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• v.20 no.4
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• pp.483-498
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• 2017

Real-Time Hybrid Simulation (RTHS) is a powerful and cost-effective dynamic experimental technique. To implement a stable and accurate RTHS, time delay present in the experiment loop needs to be compensated. This delay is mostly introduced by servo-hydraulic actuator dynamics and can be reduced by applying appropriate compensators. Existing compensators have demonstrated effective performance in achieving good tracking performance. Most of them have been focused on their application in cases where the structure under investigation is subjected to inputs with relatively low frequency bandwidth such as earthquake excitations. To advance RTHS as an attractive technique for other engineering applications with broader excitation frequency, a discrete-time feedforward compensator is developed herein via various optimization techniques to enhance the performance of RTHS. The proposed compensator is unique as a discrete-time, model-based feedforward compensator. The feedforward control is chosen because it can substantially improve the reference tracking performance and speed when the plant dynamics is well-understood and modeled. The discrete-time formulation enables the use of inherently stable digital filters for compensator development, and avoids the error induced by continuous-time to discrete-time conversion during the compensator implementation in digital computer. This paper discusses the technical challenges in designing a discrete-time compensator, and proposes several optimal solutions to resolve these challenges. The effectiveness of compensators obtained via these optimal solutions is demonstrated through both numerical and experimental studies. Then, the proposed compensators have been successfully applied to RTHS tests. By comparing these results to results obtained using several existing feedforward compensators, the proposed compensator demonstrates superior performance in both time delay and Root-Mean-Square (RMS) error.

• Korean Institute of Interior Design Journal
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• v.19 no.2
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• pp.107-116
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• 2010

In Europe, traditionally the low-rised buildings for public art museum have been constructed since the 18th century like any other buildings and these are because of the technical issue for construction difficulty. Even if the low-rised art museum buildings are still continued for it's construction, gradually the high-rised art museum buildings begin to be build due to the development of contemporary technology in high-dense modern urban space. This tendency of high-rised art museum building in recent years is expected to affect on the interior space of it and most of all the spatial change in conjunction with circulation system variation is remarkable. Because the circulation system in art museum means tourist's spatial experience and it normally controls the experience of knowledge in art museum. This study is to understand how the multi-floored art museums in Europe affect to the spatial structure and how this is related to the circulation system. And also the study raised an issue on what it's social meaning is. Through these analysis the study can provide the meaning of multi-floored art museum and basic indication in art museum planning. To understand this, the study calculated the number of stories, number of vertical circulation and number of ring-structure space. Also the study tired to use space syntax tools, which are connectivity, integration value, integration value in major space, integration value in vertical circulation and intelligibility value. those tools alculated topological transfiguration of the whole space.Throughout the study, it was concluded that the influence of high-rised art museum in Europe changed the spatial structure and circulation system. The topological center of art museum that has been the grand space since 18th century changed to the vertical circulation due to the it's roll of distributing visitors to each floor. It became a starting point of spatial deployment and experience in art museum.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.1
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• pp.22-30
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• 2014

"ImwonGyeongjeji" is recognized the value which is unparalleled encyclopedia in the world, but that is only evaluate about variously handled with subject area and massive content and also most scholarly research was focusing agriculture which is the domestic situation of published period and "ImwonGyeongjeji" judged as a simple agriculture book. Therefore, this research focus to theory and technique of traditional landscape architecture from science of landscape architecture perspective and it is from "ImwonGyeongjeji" which is known as encyclopedia written by Seo Yu-gu in 19th century Joseon period. For such a contents, "ImwonGyeongjeji" can find a importance that it have value and status for represent of Korea 'landscape architecture statement' which compared with other East Asia in those aspects; 'professional about landscape architecture', 'superiority of composition system', indigenousness suitable for Korea' and 'enhance to superiority value of environmental factor for writing'.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.5
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• pp.26-38
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• 2000

The purpose of this study is to perform a comparative analysis on landscape ordinances between Korea and U.S.A to find out some useful implications for remedial devices on Korean landscape ordinances in terms of their legislation, contents, and operating procedure. The results of this study are as follows; 1) Technical issues addressed by the U.S.A landscape ordinances may be divided broadly into five items(landscaping, planting, facilities, land use, preservation and protection) and subdivided diversely by each item. 2) The thirty four landscape ordinances of U.S.A., collected for this study, were made up of the nineteen comprehensive landscape ordinances(56%), the nine tree ordinances(26%) and the six post construction landscape ordinances(18%) s a result classifying into three types(comprehensive, post-construction, and tree ordinances) of landscape ordinances. 3) The differences in the view of the legislation, contents and practical process in the Korea and the U.S.A. landscape ordinances were to be analyzed comparatively. 4) Whether or not of applying the thirty four landscape ordinances of U.S.A. to the domestic ordinances were reviewed, we found that the twenty eight cases are applicable after study(82%), the four cases are applicable(12%) and the two cases are not applicable(6%) to Korean system. The result of this study will be source materials for the application of the correct regulations in the field of domestic landscape ordinances providing the theoretical system for the legislation of the landscape ordinances which are characterized as the harmonization between the development and the conservation breaking from the existing uniform and the developmental landscape ordinances.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.3
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• pp.180-192
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• 2013

Recently, the development of the information-communications industry has created a new paradigm of the ubiquitous and the smart environments. An USN is a typical technology for constructing a ubiquitous environments. But the USN technologies applied in practice have a lot of problems and to solve these problems that this study was to build a test bed. For the creation of the needs of USN technology, we suggest a method and service of monitoring of road hazards combining the USN and the Geographic Information System(GIS). We conduct making the USN equipment relevant provisions surveys, making installation guidelines, construction system and real-time testing. This study is capable of the management of public facilities, real-time monitoring of accident and the environment data and is expected to be expanded to a 3D facility management combineded with BIM in the future.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.347-352
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• 2001

Midtown redevelopment project is intended for restoration of city's declining function and promoting the utilization of land, but several factors such as participants of different nature in the project, different expectation level from them, high land value accompanied by geographical location as a city and the demand for high density development, nature of business that requires long duration to complete and vast amount of fund contribute to complication of feasibility study. Due to these characteristics of midtown redevelopment project, consideration of various factors involved with it and reliable analysis are required but suggested complication of feasibility study is causing halt in project, preventing from launching it and delaying it. So, this study was undertaken to be a help to feasibility study of midtown redevelopment project by suggesting main elements that need to be dealt with analysing questionnaire survey result attained from related expert in this area and arranging total 45 factors essential to feasibility study for midtown redevelopment project that can be classified into 5 main category such as economic/financial factors, legal/institutional factors, market related factors, technical factors and conflict related factors through documental investigation, case study and interview with specialist concerned.