• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.176.5-176
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• 2001

This paper presents a fuzzy dynamic output feedback controller design method for Parallel Distributed Compensation (PDC)-type Takagi-Sugeno (T-S) model based fuzzy dynamic system with H$\infty$ performance and additional constraints on the closed pole placement. Design condition for these controller is obtained in terms of the linear matrix inequalities (LMIs). The proposed fuzzy controller satisfies the disturbance rejection performance and the desired transient response. The design method is verified by this method for an inverted pendulum with a cart using the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.63.4-63
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• 2002

$\textbullet$ Closed System Identification for inherently unstable systems $\textbullet$ Application of Observer/controller Identification (OCID) algorithm to those systems $\textbullet$ An open-loop system model with corresponding controller and observer gains are identified using OCID $\textbullet$ Experimental example of the OCID algorithm for an inverted pendulum system operating in closed-loop $\textbullet$ Modal analysis and time response to the added distrubance are presented to evaluate the performance of the OCID algorithm.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.53-62
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• 2004

In this paper the overstrength factors, ductility factors, and response modification factors of ordinary concentric braced frames designed in accordance with a current seismic design code are determined by performing pushover analysis. According to the analysis results, the overstrength and the response modification factors turn out to be larger than the values regulated in the codes in most model structures. However if the braces are reinforced by BRB or zipper columns, the overstrength factors and response modification factors turn out to increase significantly.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.5
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• pp.203-216
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• 2021

Analyzing various wave interactions with oscillating wave surge converters (OWSC) is essential because they must be operated efficiently under a wide range of wave conditions and designed to extract optimal wave energy. In the conceptual design and development stage of OWSC, numerical analysis can be a good alternative as a design tool. This study performed a numerical analysis on the behavioral characteristics of the inverted triangle flap against the incident waves using open source CFD to examine the essential behavioral attributes of OWSC. Specifically, the behavioral characteristics of the structure were studied by calculating the free water surface displacement and the flap rotation angle near the inverted triangular flap according to the change of the period under the regular wave conditions. By comparing and examining the numerical analysis results with the hydraulic model experiments, the validity of the analysis performed and the applicability in analyzing the wave-structure interactions related to OWSC was verified. The numerical analysis result confirmed that the hydrodynamic behavior characteristic due to the interactions of the wave and the inverted triangle flap was well reproduced.

• The Korean Journal of Zoology
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• v.26 no.3
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• pp.193-202
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• 1983

Inversion at variable time of the uncleaved eggs of Rana nigromaculata and Rana dybowskii was emplyed to study the mechanisms of early embryogenesis. The response to inversion varied between those two spcies. If the eggs were inverted at early time it was possible to change the site of the first cleavage furrow of Rana nigromaculata-it appeared on the original vegetal hemisphere (OpG side). However, the first cleavage furrow of Rana dybowskii was not changed at all no matter what its inversin time was-it always appeared on the original animal hemisphere (G. side). In the inverted Rana nigromaculata embryos the size of the blastomeres on the vegetal hemisphere was always smaller than those of animal hemisphere. On the ocntrary, the cleavage pattern of Rana dybowskii was not altered. Results of the histological works for the inverted eggs suggest that the different responses to inversion might be caused by the fact that the extent to which the redistribution of the egg components such as cleavage nuclei and yolk platelets are different.

• Earthquakes and Structures
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• v.8 no.5
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• pp.1191-1214
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• 2015

The Theory of Plastic Mechanism Control (TPMC) has been recently extended to the case of Eccentrically Braced Frames (EBFs) with inverted Y-scheme, i.e., EBFs with vertical links. In this paper a further validation of the design procedure, based on TPMC, is provided by means of Incremental Dynamic Analyses (IDA) pointing out the fulfilment of the design goal, i.e., the development of a pattern of yielding consistent with the collapse mechanism of global type where all the links are yielded and all the beams are yielded at their ends while all the columns and the diagonal braces remain in elastic range with the only exception of the base sections of first storey columns. In particular, a study case is designed according to both TPMC and Eurocode 8 provisions and the corresponding seismic performances are investigated by both push-over and IDA analyses. The results show the different performances obtained in terms of pattern of yielding, maximum interstorey drift, link plastic rotation demand and sharing of the seismic base shear between the moment-resisting part and the bracing part of the structural system. The seismic performance improvement obtained by means of TPMC, compared to Eurocode 8 provisions, is pointed out.

• Structural Engineering and Mechanics
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• v.50 no.1
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• pp.1-17
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• 2014

In this paper, overstrength, ductility and response modification factors are calculated for frames braced with a different type of buckling restrained braces, called reduced yielding segment BRB (Buckling Restrained Brace) in which the length of its yielding part is reduced and placed in one end of the brace element in comparison with conventional BRBs. Forthermore, these factors are calculated for ordinary BRBF and the results are compared. In this regard incremental dynamic analysis (IDA) method is used for studying 17 records of the most known earthquakes happened in the world. To do that, the considered buildings have different stories and two bracing configurations: diagonal and inverted V chevron, the most ordinary configurations of BRBFs. Static pushover analysis, nonlinear incremental dynamic analysis and linear dynamic analysis have been performed using OpenSees software. Considering the results, it can be seen that, overstrength, ductility and response modification factors of this type of BRBF(Buckling Restrained Braced Frame) is greater than those of conventional types and it shows better seismic performance and also eliminates some of conventional BRBF's disadvantages such as low post-yield stiffness.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.29-37
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• 2004

The overstrength factor and the ductility factor are the two important factors that determine response modification factors used in current seismic codes, In this paper the overstrength and ductility factors of special concentric braced frames are determined by performing pushover analysis of model structures with various stories and span lengths. and by using those factors the response modification factors are obtained. According to the analysis results. the overstrength and the ductility factors are larger than the values proposed by the codes in low-rise structures. and the opposite is true in medium to high-rise structures, It is also found that the factors increase as the height of structures decreases and the span length increases.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.5
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• pp.393-398
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• 2001

This paper presents a new method with time-varying boundary layer and input gain, variated by Fuzzy Logic Control(FLC) by means of the system state in Sliding Mode Control (SMC). In addition to the time-varying boundary layer, the time-varying range of the fuzzy membership function has an effect on not only chattering reduction but also fast response characteristics. On the basis of SMC with time-varying boundary and FLC with time-varying input and output range, a computer simulation for inverted pendulum results in elimination of the chattering phenomenon and fast response.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.1
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• pp.27-33
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• 2009

Human postural responses appeared to have stereotyped modality, such as ankle mode, knee mode and hip mode in response to various perturbations. We examined whether human postural control gain of full-state feedback could be decoupled along with the eigenvector. To verify the model, postural responses subjected to fast backward perturbation were used. Upright posture was modeled as 3-segment inverted pendulum incorporated with feedback control, and joint torques were calculated using inverse dynamics. Postural modalities such as ankle, knee and hip mode were obtained from eigenvectors of biomechanical model. As oppose to the full-state feedback control, independent eigenvector control assumes that modal control input is determined by the linear combination of corresponding modality. We used optimization method to obtain and compare the feedback gains for both independent eigenvector control and full-state feedback control. As a result, we found that simulation result of eigenvector feedback was not competitive in comparison with that of full-state feedback control. This implies that the CNS would make use of full-state body information to generate compensative joint torques.