• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.496-498
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• 2005

This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also by using the power series, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs).

• Structural Engineering and Mechanics
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• v.31 no.3
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• pp.315-331
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• 2009

Mechanical connections are recognized as extremely important elements in the aspect of strength and structural safety. However, classical structural model does not consider the connection stiffness properties, and are based on models with pinned or rigid joints only. In fact, mechanical connections are deformable and behave not linearly, affecting the whole structure and inducing nonlinear behavior as well. The quantification of this effect, however, depends on the description of the working of the connectors and the wood response under embedment. The theoretical modeling of wood structures with semi-rigid connections involves not only the structural analysis, but also the modeling of both single and grouped moment resisting connectors and the study of the wood properties under embedment. The proposal of this paper is to approach these aspects, and to quantitatively study the influence of the moment resistant connection in wooden framed structures. Comparisons between rigid and semi-rigid connections and between linear and nonlinear analysis lead to quantitative results.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.1
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• pp.121-128
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• 2005

This paper proposes the heuristic approach for the generalized GT(Group Technology) problem to consider the restrictions which are given the number of cell, maximum number of machines and minimum number of machines. This approach is classified into two stages. In the first stage, we use the similarity coefficient method which is proposed and calculate the similarity values about each pair of all machines and align these values in descending order. If two machines which is selected is possible to link the each other on the edge of machine cell and they don't have zero similarity value, then we assign the machines to the machine cell. In the second stage, it is the course to form part families using proposed grouping efficacy. Finally, machine-part incidence matrix is realigned to block diagonal structure. The results of using the proposed approach are compared to the Modified p-median model.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.135-140
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• 1998

The concept of dissipativity and passivity are of interest to us from a theoretical as well as a practical point of view. It is well known that the Riccati equation is derived from the dissipation inequality which expresses the fact that the system is dissipative; the energy stored inside the system doesn't exceed the amount of supply which flows into the system. The pencil model is regarded as a representation based on behavioral approach introduced by J.C. Willems. It has first order in the internal variable and zeroth order in the external variable. In general, any matrix pencil is transformed into a canonical form which is consist of several kind of sub-pencils, One of them has row full rank for $^\forall S\;\in\;\mathds{C}\;\bigcup{\infty}$, we call it under-determined mode of the model. In our opinion, most important properties of dynamical system lay in the mode. According to the properties of canonical form for pencil, it is shown that the storage function which characterizes the dissipativity of the system can be written as a LMI for the under-determined mode, if the system doesn't include impulse mode.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.1
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• pp.13-21
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• 2005

This paper presents a fuzzy model-based approach for synchronization of time-delay chaotic system with input saturation. Time-delay chaotic drive and response system is respectively represented by Takagi-Sugeno (T-S) fuzzy model. Specially, the response system contains input saturation. Using the unidirectional linear error feedback and the parallel distributed compensation (PDC) scheme, we design fuzzy chaotic synchronization system and analyze local stability for synchronization error dynamics. Since time-delay in the transmission channel always exists, we also take it into consideration. The sufficient condition for the local stability of the fuzzy synchronization system with input saturation and time-delay is derived by applying Lyapunov-Krasovskii theory and solving linear matrix inequalities (LMI's) problem. A numerical example is given to demonstrate the validity of the proposed approach.

• Computers and Concrete
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• v.20 no.2
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• pp.229-246
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• 2017

The dynamic bending response of single walled carbon nanotube reinforced composite (SWCNTRC) plates subjected to hygro-thermo-mechanical loading are investigated in this paper. The mechanical load is considered as wind pressure for dynamic bending responses of SWCNTRC plate. The dynamic version of the High Order shear deformation Theory (HSDT) for a composite plate with Matrix and SWCNTRC plate is first formulated. Distribution of fibers through the thickness of the SWCNTRC plate could be uniform or functionally graded (FG). The dynamic displacement response is predicted by using Nemarck integration method. The effective material properties of SWCNTRC are estimated by using micromechanics based modeling approach. The effect of different environmental condition, volume fraction of SWCNT, Width-to-thickness ratio, wind pressure, different SWCNTRC-FG plates, boundary condition, E1/E2 ratio, different temperature on dynamic displacement response is investigated. The dynamic displacement response is compared with the available literature and it shows good agreement.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.8
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• pp.710-716
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• 2010

This note represents a new disturbance observer to reduce effects of external disturbances. In case of conventional disturbance observers, additional stabilizing filters, so-called Q-filter, should be used because the conventional ones don't guarantee stability. But, the proposed one doesn't need the stabilizing filter, which is a fundamentally different research result from previous methods. Experimental verifications show this approach is realizable and valid to enhance precise positioning.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1492-1495
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• 2005

This paper presents a new linear-matrix-inequality-based intelligent digital redesign (LMI-based IDR) technique to match the states of the analog and the digital T-S fuzzy control systems at the intersampling instants as well as the sampling ones. The main features of the proposed technique are: 1) the affine control scheme is employed to increase the degree of freedom; 2) the fuzzy-model-based periodic control is employed; and the control input is changed n times during one sampling period; 3) The proposed IDR technique is based on the approximately discretized version of the T-S fuzzy system; but its discretization error vanishes as n approaches the infinity. 4) some sufficient conditions involved in the state matching and the stability of the closed-loop discrete-time system can be formulated in the LMIs format.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.227-230
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• 1998

In this paper, we propose the design method of fuzzy robust H$\infty$ controller for the uncertain nonlinear discete-time systems with time delay. First, we represent a nonlinear plant with a modified T-S(Takagi-Sugeno) fuzzy model. Then design method utilizing the concept of PDC (parallel distributed compensation) is employed. For the modified T-S fuzzy model with uncertainty and delay, the sufficient condition of the quadratic stabilization with an H$\infty$ norm bound is presented in terms of Lyapunov stability theory and fuzzy robust H$\infty$ controller design method is given by LMI(linear matrix inequality) approach. Also an illustrative example is given to demonstrate the result of the proposed method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.3
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• pp.115-121
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• 2014

HVAC&R system costs can often be one of the most expensive components, representing approximately 15% of the total construction cost for office buildings. Despite their significant importance, there is a lack of a consistent and homogeneous framework to approximate the estimate research. This research deals with the prediction methodology of HVAC&R system cost with the aim of establishing a common idea for the analysis of the construction cost estimate. Our approach deals with the concept of an HVAC&R set that is composed of subsystems. The matrix combination analysis is examined, and total 960 HVAC&R system cost estimation can be implemented to large scale office buildings.