• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.4
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• pp.29-36
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• 2010

To investigate the cyclic characteristics of exterior joints in RC frame buildings which are typically used after 1988, 70% scaled T-shaped beam-column subassemblies were designed and tested with a displacement control that is composed of 9 steps, until 3.5% story drift was reached. Axial forces are applied to columns during the experiment to simulate a real situation. The results show that the non-seismic detailed specimens failed before reaching 0.85% story drift, and their strengths are less than 0.85 times the nominal flexural strength which beam or columns should reach. The relationship of principal stress and story drift of exterior joints is similar to the one that Priestly proposed.

• Structural Engineering and Mechanics
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• v.13 no.4
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• pp.369-385
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• 2002

Ductility capacity is comprehensively studied for steel moment-resisting frames. Local, story and global ductility are being considered. An appropriate measure of global ductility is suggested. A time domain nonlinear seismic response algorithm is used to evaluate several definitions of ductility. It is observed that for one-story structures, resembling a single degree of freedom (SDOF) system, all definitions of global ductility seem to give reasonable values. However, for complex structures it may give unreasonable values. It indicates that using SDOF systems to estimate the ductility capacity may be a very crude approximation. For multi degree of freedom (MDOF) systems some definitions may not be appropriate, even though they are used in the profession. Results also indicate that the structural global ductility of 4, commonly used for moment-resisting steel frames, cannot be justified based on this study. The ductility of MDOF structural systems and the corresponding equivalent SDOF systems is studied. The global ductility values are very different for the two representations. The ductility reduction factor $F_{\mu}$ is also estimated. For a given frame, the values of the $F_{\mu}$ parameter significantly vary from one earthquake to another, even though the maximum deformation in terms of the interstory displacement is roughly the same for all earthquakes. This is because the $F_{\mu}$ values depend on the amount of dissipated energy, which in turn depends on the plastic mechanism, formed in the frames as well as on the loading, unloading and reloading process at plastic hinges. Based on the results of this study, the Newmark and Hall procedure to relate the ductility reduction factor and the ductility parameter cannot be justified. The reason for this is that SDOF systems were used to model real frames in these studies. Higher mode effects were neglected and energy dissipation was not explicitly considered. In addition, it is not possible to observe the formation of a collapse mechanism in the equivalent SDOF systems. Therefore, the ductility parameter and the force reduction factor should be estimated by using the MDOF representation.

• Earthquakes and Structures
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• v.26 no.3
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• pp.175-189
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• 2024

Aiming at studying the plastic hinge (PH) evolution regularities and failure mode of rocking wall moment frame (RWMF) structure in earthquakes, the whole-working history analysis of seismic performance state of RWMF structure based on co-operation performance and PH evolution was carried out. Building upon the theoretical analysis of the elastic internal forces and deformations of RWMF structures, nonlinear finite element analysis (FEA) methods were employed to perform both Pushover analysis and seismic response time history analysis under different seismic coefficients (δ). The relationships among PH occurrence ratios (R_ph), inter-story drifts and δ were established. Based on the plotted curve of the seismic performance states, evaluation limits for the R_ph and inter-story drifts were provided for different performance states of RWMF structures. The results indicate that the R_ph of RWMF structures exhibits a nonlinear evolution trend of "fast at first, then slow" with the increasing of δ. The general pattern is characterized by the initial development of beam hinges in the middle stories, followed by the development towards the top and bottom stories until the beam hinges are fully formed. Subsequently, the development of column hinges shifts from the bottom and top stories towards the middle stories of the structure, ultimately leading to the loss of seismic lateral capacity with a failure mode of partial beam yield, demonstrating a global yielding pattern. Moreover, the limits for the R_ph and inter-story drifts effectively evaluate the five different performance states of RWMF structures.

• Earthquakes and Structures
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• v.18 no.2
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• pp.171-184
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• 2020

The potential of using the roof water tanks as a mitigation measure to minimize the required separation gap and induced pounding forces due to collisions is investigated. The investigation is carried out using nonlinear dynamic analysis for two adjacent 3-story buildings with different dynamic characteristics under two real earthquake motions. For such analysis, nonlinear viscoelastic model is used to simulate forces due to impact. The sloshing force due to water movement is modelled in terms of width of the water tank and the instantaneous wave heights at the end wall. The effect of roof water tanks on the story's responses, separation gap, and magnitude and number of induced pounding forces are investigated. The influence of structural stiffness and storey mass are investigated as well. It is found that pounding causes instantaneous acceleration pulses in the colliding buildings, but the existence of roof water tanks eliminates such acceleration pulses. At the same time the water tanks effectively reduce the number of collisions as well as the magnitude of the induced impact forces. Moreover, buildings without constructed water tanks require wider separation gap to prevent pounding as compared to those with water tanks attached to top floor under seismic excitations.

• Korean Journal of Child Studies
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• v.33 no.3
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• pp.149-175
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• 2012

This study is designed to positively transform a teacher's emotional state whilst teaching their classes and be able to create happier lessons for preschool children. To do this, a teacher needs to reflect upon current problems and take steps to deal with them. The data for this study was collected from participatory observation and in-depth interviews, making use of photos, a reflective teacher's journal and interview records from Mar. 28, 2011 through Oct. 7, 2011. The problems identified were, (1) teacher centered classes, (2) a daily routine filled with large group activities, (3) disruptive students, and (4) repetitiveness. The routes to greater classroom "happiness" are (1) rearranging seats, (2) "story sharing activities" in small groups, (3) making a separate "story sharing activity" area, (4) using small groups instead of large groups, (5) changing the daily routine. The role of the teacher in finding greater "happiness" are (1) meaningful, 'real observation', (2) discovering genuine change from small points, (3) power sharing, and (4) growing and developing with children.

• Cartoon and Animation Studies
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• s.24
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• pp.173-197
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• 2011

Through a story, the audience moves between fiction and reality. A story is an emotional experience that appeals to human feeling. The rational function of a story is to convey knowledge and information, and its emotional function is to touch the audience. Moreover, these aspects of a story are linked to its language, text, and imagery. This paper focuses on the emotional function of a story. In a experiential story, the audience's emotional response is a result of maximum dramatic communication between them and the characters. Through psychological and mental communion with the characters, the audience becomes immersed in the story when they emotionally identify with the characters, and dramatic communication is achieved. However, dramatic communication is mostly achieved instantaneously. The elements of a film need to be realized to sustain dramatic communication such that the audience continues to be immersed in the story. The audience can identify with the characters who are placed in real-life situations by considering the characters' external and internal aspects. External search pertains to the tangible aspects of the character such as its background, life, and conversation. Through the audience's external search, the characters communicate with the audience. Internal search deals with aspects of the characters' personality such as their self-concept, desires, and internal conflicts. Through internal search, the audience understands the inner side of the characters. In this process, a film director should ensure that the acting depicts the inner side of the characters. In other words, the director should perfectly depict the internal and external elements of a human on screen. Appropriate visualization can lead to dramatic communication with the characters and thereby create the audience's emotional response. Considering these techniques, this paper focuses on the scenes of the film "Poetry" in which dramatic communication with the characters creates the audience's emotional response. Accordingly, the audience plays a role in sustaining dramatic communication for the physical screen time of a film.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.189-194
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• 2007

An experimental real-time hybrid method, which implements the wind response control of a building structure with only a two-way TLMD, is proposed and verified through a shaking table test. The building structure is divided into the upper experimental TLMD and the lower numerical structural part. The shaking table vibrates the TLMD with the response calculated from the numerical substructure, which is subjected to the excitations of the measured interface control force at its top story and an wind-load input at its base. The results show that the conventional method can be replaced by the proposed methodology with a simple installation and accuracy for evaluating the control performance of a TLMD.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.2
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• pp.302-318
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• 2011

The object of this study is to provide easily-understandable mathematics class to highschool students, who usually take no interest in mathematics, by apply teaching strategy based on storytelling to real lessons. The approaching methods for the mathematics education are emphasizing the mathematical education during making storytelling-studying plans, inducing the interest of the students by applying the mathematical situations in the story. The effects of the storytelling such as induction of the interest, persistency, perception of the practicality, smooth communication between teachers and students coincides with the way national mathematical education orients. This study contains the definition of the storytelling based on education, and applicability to the students, and application to the real lessons, and verification of the effects by focus-group interview with the students and observing teachers. I made the lesson plan based on storytelling for achievements to the object of the highschool mathematical study, and searched the best way to apply the lesson plan to the real lessons. I studied designing lesson strategy based on dissertations and books and reports directly related this study, and did focus-group interview to find advantages and disadvantages of the strategy. And finally I could make the well-applicable lesson plan.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.485-495
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• 2008

An experimental real-time hybrid method, which implements the vibration control of a building structure with only a two-way TLMD, is proposed and verified through a shaking table test. The building structure is divided into the upper experimental TLMD and the lower numerical structural part. The shaking table vibrates the TLMD with the response calculated from the numerical substructure, which is subjected to the excitations of the measured interface control force at its top story and sinusoidal waves input at its base. The results show that the conventional method can be replaced by the proposed methodology with a simple installation and accuracy for evaluating the control performance of a TLMD.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.174-182
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• 2014

To monitor the wind-induced responses of buildings, conventional real-time kinematic (RTK) methods based on two global positioning system (GPS) receivers (e.g., a reference and a rover) are widely applied. However, these methods can encounter problems such as difficulty in securing and maintaining a space for a reference station. With the recently developed virtual reference station (VRS)-RTK approach, the position of a structure can be measured using only a rover receiver. In this study, to evaluate the applicability of VRS-RTK methods in monitoring the lateral structural responses of frame structures, we performed free vibration tests on a one-story frame model (the first natural frequency of 1 Hz) and a three-story frame model (the first natural frequency of 0.85 Hz). To assess the reliability of the displacement and acceleration responses measured by the GPS, we performed a concurrent measurement using laser displacement sensors and an accelerometer. The accelerometer results were consistent with the GPS measurements in terms of the time history and frequency content. Furthermore, to derive an appropriate sampling rate for the continuous monitoring of buildings, the errors in the displacement responses were evaluated at different GPS sampling rates (5, 10, 20 Hz). The results indicate that as the sampling rate increased, the errors in the displacement responses decreased. In addition, in the three-story model, all modal components (first, second, and third modes) could be recorded at a sampling rate of 20 Hz.