• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.29-40
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• 2001

Steel frames are increasingly used in commercial buildings. and most steel frames are designed to achieve composite action with the concrete floor slab. The advantages of 'composite construction' are now well understood in terms of structural economy. good performance in service. and ease of construction. But. these conventional composite construction system are difficult to apply steel framed apartment due to their large depth. So. in this study we developed Semi Slim Floor system which could reduce the overall depth of composite beam. Semi Slim Floor system is a method of steel frame multi-story building construction in which the structural depth of each floor is minimised by incorporating the steel floor beams within the depth of the concrete floor slab. Twelve composite slab specimens with different deck-type. slab width. with or without stud bault and concrete topping thickness were tested to evaluate the flexural capacity.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.587-598
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• 2004

In this study, an experiment was conducted on the Slim Floor system, using a hollow core PC slab, which could reduce the over-all depth of a composite beam. The Slim Floor system is a method used in steel frame multi-story building construction, in which the structural depth of each floor is minimized after incorporating the steel floor beams within the depth of the concrete floor slab. This experimental study focused on the flexural behavior of the partially connected Slim Floor system with asymmetric steel beams encased in hollow core PC slabs. Ten full-scale specimens were constructed and tested in this study, with different steel beam heights, hollow core PC slabs, slab widths, and PC slab bearings. Observations made in line with the experiments indicated that the degree of shear connection without additional shear connection was 0.48-0.98 times more than that of the full shear connection, due to inherent mechanical and chemical bond stress.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.455-473
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• 2016

Methods for the seismic demands evaluation of structures require iterative procedures. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformations and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the Performance-Based Seismic Design (PBSD) through Capacity-Spectrum Method (CSM). For instance, the Modal Pushover Analysis (MPA) has been proved to provide accurate results for inelastic buildings to a similar degree of accuracy than the Response Spectrum Analysis (RSA) in estimating peak response for elastic buildings. In this paper, a simplified nonlinear procedure for evaluation of the seismic demand of structures is proposed with its applicability to multi-degree-of-freedom (MDOF) systems. The basic concept is to write the equation of motion of (MDOF) system into series of normal modes based on an inelastic modal decomposition in terms of ductility factor. The accuracy of the proposed procedure is verified against the Nonlinear Time History Analysis (NL-THA) results and Uncoupled Modal Response History Analysis (UMRHA) of a 9-story steel building subjected to El-Centro 1940 (N/S) as a first application. The comparison shows that the new theoretical approach is capable to provide accurate peak response with those obtained when using the NL-THA analysis. After that, a simplified nonlinear spectral analysis is proposed and illustrated by examples in order to describe inelastic response spectra and to relate it to the capacity curve (Pushover curve) by a new parameter of control, called normalized yield strength coefficient (${\eta}$). In the second application, the proposed procedure is verified against the NL-THA analysis results of two buildings for 80 selected real ground motions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.6
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• pp.301-308
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• 2018

This paper presents an optimal design method of a hybrid structural control system considering multi-hazard. Unlike a typical structural control system in which one system is designed for one specific type of hazard, a simultaneous optimal design method for both active and passive control systems is proposed for the mitigation of seismic and wind induced vibration responses of structures. As a numerical example, an optimal design problem is illustrated for a hybrid mass damper(HMD) and 30 viscous dampers which are installed on a 30 story building structure. In order to solve the optimization problem, a self-adaptive Harmony Search(HS) algorithm is adopted. Harmony Search algorithm is one of the meta-heuristic evolutionary methods for the global optimization, which mimics the human player's tuning process of musical instruments. A self-adaptive, dynamic parameter adjustment algorithm is also utilized for the purpose of broad search and fast convergence. The optimization results shows that the performance and effectiveness of the proposed system is superior with respect to a reference hybrid system in which the active and passive systems are independently optimized.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.7
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• pp.81-88
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• 2019

The purpose of this study is to investigate the relations between brick and stone brick pagodas in all classes of pagoda with their construction and shape. Research objects of this study are brick and stone brick pagodas of National Treasure and Treasure and masonry pagodas that are similar to brick and stone brick pagoda. This study includes checking preceding researches, drawing questions from these preceding researches, and finding answers from these questions. The results of this study are as follows. First, pagoda of Bunhwangsa Temple, the first pagoda in the Silla Dynasty, was built as a masonry pagoda, not a stone brick pagoda. Second, roofs of stone brick pagoda barrows from brick pagoda's techniques for performance of material and ease construction. Third, brick or stone brick pagodas' base have Type II that has low and extensive foundation with soil and stones usually. Forth, Korean pagodas are categorized by their materials, construction methods, and shapes. Wooden pagodas, stone pagodas, and brick pagodas are categorized by materials, post-and lintel pagodas and masonry stone pagodas are categorized by construction methods, and pitched roof pagodas and terraced roof pagodas are categorized by shapes. Fifth, masonry pagodas of Buddhism that have shape of multi-story building were developed from Doltap, traditional stone stack, and they advanced with brick pagodas and stone pagodas to terraced roof stone pagodas and post-and lintel base brick pagodas.

• Wind and Structures
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• v.37 no.6
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• pp.445-460
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• 2023

Accurate estimation of modal parameters (i.e., natural frequency, damping ratio) of tall buildings is of great importance to their structural design, structural health monitoring, vibration control, and state assessment. Based on the combination of variational mode decomposition, smoothed discrete energy separation algorithm-1, and Half-cycle energy operator (VMD-SH), this paper presents a method for structural modal parameter estimation. The variational mode decomposition is proved to be effective and reliable for decomposing the mixed-signal with low frequencies and damping ratios, and the validity of both smoothed discrete energy separation algorithm-1 and Half-cycle energy operator in the modal identification of a single modal system is verified. By incorporating these techniques, the VMD-SH method is able to accurately identify and extract the various modes present in a signal, providing improved insights into its underlying structure and behavior. Subsequently, a numerical study of a four-story frame structure is conducted using the Newmark-β method, and it is found that the relative errors of natural frequency and damping ratio estimated by the presented method are much smaller than those by traditional methods, validating the effectiveness and accuracy of the combined method for the modal identification of the multi-modal system. Furthermore, the presented method is employed to estimate modal parameters of a full-scale tall building utilizing acceleration responses. The identified results verify the applicability and accuracy of the presented VMD-SH method in field measurements. The study demonstrates the effectiveness and robustness of the proposed VMD-SH method in accurately estimating modal parameters of tall buildings from acceleration response data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.65-72
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• 2022

Recently, damage to buildings due to earthquakes in Korea occurred mainly in school buildings and Piloti-type multi-family houses, highlighting the need for seismic retrofit for buildings of the same type. In the early days of the seismic retrofit project for school facilities, various patented methods using dampers as a ductile seismic retrofit method were applied without sufficient verification procedures. However, in 「School Facility Seismic Performance Evaluation and Retrofit Manual, 2021」, when the patented method is applied, it must be applied through a separate strict verification procedure, and instead, the strength/stiffness retrofit method was induced as a general method. In practice,when evaluating seismic performance for retrofit by infilled steel frame with brace, the analysis model is constructed by directly connecting only the steel brace to the existing RC member. However, if the frame is removed from the analysis model of the infilled steel frame with brace, the force reduction occurring on the existing RC member near the retrofit is considered to be very large, and this is judged to affect the review of whether to retrofit the foundation or not. Therefore, in this study, preliminary analysis with variables such as whether or not steel frame is taken into account and frame link method for the analysis model of RC school building retrofitted by infilled steel frame with brace and nonlinear analysis for actual 3-story school building was performed, and basic data for rational analysis model setting were presented by comparing preliminary analysis and pushover analysis results for each variable.

• Archives of design research
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• v.18 no.4 s.62
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• pp.53-64
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• 2005

The emergence of new communication media, digital, is something of a wonder, as well as a cultural tension. The industrial technologies that dramatically expand human abilities are being developed much faster than the speed of adaptation by humans. Without an exception, it creates new contents and form of the culture by shaking the very foundation of the notion about human beings. Korean broadcasting environment has stepped into the era of multi-media, multi-channel as the digital technology separated the media into network, cable, satellite and internet. In this digital culture, broadcasting, as a medium of information delivering and communication, has bigger influence than ever. Such changes in broadcasting environment turned the TV viewers into new consumers who participate and play the main role in active communication by choosing and using the media. This study is trying to systemize the question about the core identity of broadcasting through brand as the consumers stand in the center of broadcasting with the power to select channel. The story schema theory can be applied as a cognitive psychological tool to approach the active consumers in order to explain the cognitive processes that are related to information processing. It is a design with stories, which comes up as a case of a brand's story telling. The range of this study covers the current issue and educational programs in network TV during the period of May and August of year 2005. The cases of Korean and foreign programs were compared by the station each program is broadcasted. This study concludes that it is important to take the channel identity into the consideration in the brand strategy of each program. Especially, the leading programs of a station must not be treated as a separate program that has nothing to do with the station's identity. They must be treated to include the contents and form that builds the identity of the channel. Also, this study reconfirmed that building a brand of the anchor person can play as an important factor in the identity of the program's brand.

• Journal of architectural history
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• v.5 no.1 s.9
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• pp.50-72
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• 1996

The typical Japanese house has the characteristics of open dwellings to make them cool in the hot and humid summer. And then the traditional town house 'Machiya', being built very closely to each other and walled up both sides, it has taken the open-oriented characteristics in itself. The purpose of this study is to clarify that the open-oriented of traditional 'Machiya' has been succeeded to the new 'Machiya' in the latest. The new 'Machiya' shows the open-oriented, taking the ventilative 'Huki-nuke' space of traditional 'Machiya' as the new spatial formal elements, in the changes such as scale material space organization. The characteristics of 'Huki-nuke' space are represented as follows ; 1. The facade of the traditional 'Machiya', which has taken on a semitransparent qualty, has been generally changed to the closing qualty except for the open parts of shop and garage. This facade of the new 'Machiya' has been taken to be in keeping with the existing town as much as possible. 2. A series of three rooms, composed of shop/living dining kitchen/room from the road, have been dispersed to every floors in a building with a very extensive scale. But this serial and linear type remains as the loosefit space, and the long dwellings of the upper stories are divided by type each dwelling unit. 3. 'Tori-niwa', which is a consecutive and penetrating space, connects the road with the rooms of dwelling and functions as the circulation of man thing energy, The new 'Machiya' changed to the multi-story, the corridor and the stair have been fumed up as the elements in the place of 'Tori-niwa' The 'Huki-nuke' space was locted in the hall, stairwell, living dining kitchen room, and so on. 4. The small court yard 'Tsubo-niwa' and back yard 'Ura-niwa' at the both ends of living spaces would be made a hole in a series of rooms and enclosed by the neighboring 'Machiya'. On the contrary the new 'Machiya' at present takes in the private and closing organization enclosing the innercourt. 5. The open-oriented ${\ulcorner}$In${\lrcorner}$ or ${\ulcorner}$Out${\lrcorner}$ is not brought out because of the delicate spatial formal configuration in the traditional 'Machiya'. But the open-oriented ${\ulcorner}$In${\lrcorner}$, all sides being closed by walls, is well brought out in the new 'Machiya'.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.1-9
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• 2024

This study proposes a multi-scale template matching technique with image pyramids (TMI) to measure structural dynamic displacement using a vision sensor under atmospheric turbulence conditions and evaluates its displacement measurement performance. To evaluate displacement measurement performance according to distance, the three-story shear structure was designed, and an FHD camera was prepared to measure structural response. The initial measurement distance was set at 10m, and increased with an increment of 10m up to 40m. The atmospheric disturbance was generated using a heating plate under indoor illuminance condition, and the image was distorted by the optical turbulence. Through preliminary experiments, the feasibility of displacement measurement of the feature point-based displacement measurement method and the proposed method during atmospheric disturbances were compared and verified, and the verification results showed a low measurement error rate of the proposed method. As a result of evaluating displacement measurement performance in an atmospheric disturbance environment, there was no significant difference in displacement measurement performance for TMI using an artificial target depending on the presence or absence of atmospheric disturbance. However, when natural targets were used, RMSE increased significantly at shooting distances of 20 m or more, showing the operating limitations of the proposed technique. This indicates that the resolution of the natural target decreases as the shooting distance increases, and image distortion due to atmospheric disturbance causes errors in template image estimation, resulting in a high displacement measurement error.