• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.417-426
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• 1999

The some papers which deal with the dynamic instability for shell-like structures under the step load have been published, but there are few papers which treat the essential phenomenon of the dynamic buckling using the phase plane for investigating occurrence of chaos. In nonlinear dynamics, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and the indirect snap-buckling of shallow arches considering geometrical nonlinearity are investigated numerically and compared with the static critical load.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.6
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• pp.279-291
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• 2013

The seismic damage of non-structural components, such as communication facilities, causes direct economic losses as well as indirect losses which result from social chaos occurring with downtime of communication and financial management network systems. The current Korean seismic code, KBC2009, prescribes the design criteria and requirements of non-structural components based on their elastic response. However, it is difficult for KBC to reflect the dynamic characteristics of structures where non-structural components exist. In this study, both linear and nonlinear time history analyses of structures with various analysis parameters were carried out and floor acceleration spectra obtained from analyses were compared with both ground acceleration spectra used for input records of the analyses and the design floor acceleration spectrum proposed by National Radio Research Agency. Also, this study investigates to find out the influence of structural dynamic characteristics on the floor acceleration spectra. The analysis results show that the acceleration amplification is observed due to the resonance phenomenon and such amplification increases with the increase of building heights and with the decrease of structure's energy dissipation capacities.

• Journal of Korean Society of Steel Construction
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• v.13 no.5
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• pp.599-608
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• 2001

Many papers which deal with the dynamic instability of shell-like structures under the STEP load has been published but there have been few papers related to the dynamic instability of hybrid cable domes. And also there are a few researches which treat the essential phenomenon of the dynamic buckling using the phase for investigating occurrence of chaos. In this study the indirect buckling of hybrid cable domes considering geometric nonlinearity are investigated numerically and compared it with the static critical load The dynamic critical loads are determined by the numerical integration of the geometric nonlinear equation of motion and the mechanism of the indirect buckling is examined by using the phase curves.

• Journal of Korean Medical classics
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• v.20 no.3
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• pp.79-99
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• 2007

Basic summary of the medical administration : Due to Qing dynasty being the last of the dynastic era, it revealed overall extreme political traits in politics, economy, phenomenon, and cultural aspects. Few emperors of the early Qing dynasty adopted appeasement policy that mitigated ironies to a certain extent and showed growth in various business related fields. Even the medical administration had freshness during that period. United medical administrative system was generally formed, chicken pox was effectively prevented, shamanistic treatment was banned, medical journals were complied by the government, medical relief was more intensely done. However, actions on restoring Ming dynasty and against Qing dynasty as well as the reform power grew against Qing government threatening it. The drastically grown forces from the western region damaged Qing dynasty that the governors had to adopt despotic measures in politics, economy and culture. Social chaos began to arise, economy stagnated and weakened that the medical field also dwindled to the point where it could not be restored to the original point. The era of Qing dynasty was the period that had scientific culture at its fast growing pace, but for Chinese medicine, by contrary, due to autocracy and other factors, was faced with barriers in the medical development.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.185-190
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• 1995

In recent years, many researcher have been interested in the stability of a thin beam. Among them, Pai and Nayfeh[1] had investigated the nonplanar motion of the cantilever beam under lateral base excitation and chaotic motion, but this study is associated with internal resonance, i.e. one to one resonance. Also Cusumano[2] had made an experiment on a thin beam, called Elastica, under bending loads. In this experiment, he had shown that there exists out-of-plane motion, involving the bending and the torsional mode. Pak et al.[3] verified the validity of Cusumano's experimental works theoretically and defined the existence of Non-Local Mode(NLM), which is came out due to the instability of torsional mode and the corresponding aspect of motions by using the Normal Modes. Lee[4] studied on a thin beam under bending loads and investigated the routes to chaos by using forcing amplitude as a control parameter. In this paper, we are interested in the motion of a thin beam under torsional loads. Here the form of force based on the natural forcing function is used. Consequently, it is found that small torsional loads result in instability and in case that the forcing amplitude is increasing gradually, the motion appears in the form of dynamic double potential well, finally leads to complex motion. This phenomenon is investigated through the poincare map and time response. We also check that Harmonic Balance Method(H.B.M.) is a suitable tool to calculate the bifurcated modes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.8
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• pp.817-825
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• 2007

During thirty years, deterministic chaos has moved center stage in many areas of applied mathematics. One important stimulus for this, particularly in the early 1970s, was work on nonlinear aspects of the dynamics of plant and animal populations. There are many situations, at least to a crude first approximation, by a simple first-order difference equation. Past studies have shown that such equations, even though simple and deterministic, can exhibit a surprising array of dynamical behavior, from stable points, to a bifurcating hierarchy of stable cycles, to apparently random fluctuations. But higher-order spectral analyses of such behavior are usually not considered. Higher-order spectra of a signal contain important information that is not present in its power spectrum. So, if we find the spectral pattern and get information from it, it will be able to be used effectively in so many fields. Hence, this paper uses auto bicoherence and bicoherence residue which are sort of bispectrum. Applying these to behavior of logistic difference equation, which is typical chaotic signal, the phenomenon of phase coupling and the appearance of frequency band can be analyzed. Such information means that bispectral analysis is useful to detect nonlinearity of signal.

• Archives of design research
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• v.15 no.1
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• pp.5-14
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• 2002

Fractal which was named by Mandelbrot in 1975 and its theory have been taken notice of many fields of scholarship, namely mathematics, physics, geography, architecture, art, philosophy and so on. If we approach Fractal on the basis of the designing cogitation, it can be used not only as one of materials to take a crease thinking in design, also as a due of the methods to assess the design problem with a new point of view. Based on above background, in this study, it was studied on the graphic artist, Morits Collelius Escher who has been well known as the great artist of illusion," and on the attributes of Fractal which were contained in his various work\ulcorner As a reset, the four attributes, namey ′fractal dimension′, ′self-similarity, ′recursiveness′and ′infinity were founded in his works. Also, it was founded that Escher had employed the attributes of Fractal in his almost works for "the representation of the condition of unified-duality," that is to say, for the union of two different dimensions. After this, it is expected that this study shoed be extended to the development of the principle of Fractal-Design on the basis of ′Fractal which can be defined as the phenomenon of repetitious pattern between chaos and order and′the formative beauty of Fractal′.

• Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.167-174
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• 2006

Two typical responses have been documented for flatfish when they encounter the ground gear of bottom trawls: herding response and falling back response. These two responses were analyzed from video recordings of fish and were characterized by time sequences for four parameters: swimming speed, angular velocity, acceleration, and distance between the fish and the ground gear. When flatfish displayed the falling-back response, absolute values of the three swimming parameters and their deviations were significantly higher than those during the herding response. However, the swimming parameters were not dependent on the distance between the flatfish and the ground gear, regardless of which response occurred. The dominant periods for most of the movement parameters ranged from 2.0 to 3.7 s, except that no periodicity was observed for swimming speed or angular velocity during the falling-back response. However, variations in the four parameters during the falling -back response revealed greater irregularity in periodicity and higher amplitudes. This complex behavior is best described as a chaos phenomenon' and is discussed as the building block for a model predicting the responses of flatfish to ground gear as part of the general understanding of the fish capture process.

• Journal of Korean Association for Spatial Structures
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• v.10 no.1
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• pp.119-126
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• 2010

The some papers which deal with the dynamic instability for shell-like structures under the dynamic excitation have been published, but there are few papers which treat the essential phenomenon of the dynamic buckling using the phase plane for investigating occurrence of chaos. In nonlinear dynamic, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and indirect snapping of shallow EP shell considering geometrical nonlinearity are investigated by Galerkin method numerically. This finding out the characteristic of the dynamic instability through the phases curves and running response spectrum.

• The Journal of Dong Guk Oriental Medicine
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• v.10
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• pp.98-118
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• 2008

Basic summary of the medical administration : Due to Qing dynasty being the last of the dynastic era, it revealed overall extreme political traits in politics, economy, phenomenon, and cultural aspects. Few emperors of the early Qing dynasty adopted appeasement policy that mitigated ironies to a certain extent and showed growth in various business related fields. Even the medical administration had freshness during that period. United medical administrative system was generally formed, chicken pox was effectively prevented, shamanistic treatment was banned, medical journals were complied by the government, medical relief was more intensely done. However, actions on restoring Ming dynasty and against Qing dynasty as well as the reform power grew against Qing government threatening it. The drastically grown forces from the western region dan1aged Qing dynasty that the governors had to adopt despotic measures in politics, economy and culture. Social chaos began to arise, economy stagnated and weakened that the medical field also dwindled to the point where it could not be restored to the original point. The era of Qing dynasty was the period that had scientific culture at its fast growing pace, but for Chinese medicine, by contrary, due to autocracy and other factors, was faced with barriers in the medical development.