• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.315-319
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• 2008

We investigate theoretically the power consumption of a notch filter using a thermo-optic long-period grating, which is induced by a heater array consisting of periodic heaters and pads made of metal thin-film. Since the power consumed by the heater array is converted to joule heat that generates the thermo-optic long-period grating, the characteristics of the notch filter are dynamically controlled by adjusting it. The power necessary for appropriate coupling efficiency depends on the parameters of the heater array, which are the width and length of a heater, pad width, and the thickness of the thin-film. We explain an approximate method of analyzing the influence of the parameters on the consumed power. Using the analysis method, we simulate the change of the power depending on the parameters. From the simulation, we suggest a few guidelines on the parameters required to reduce the power.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.322-329
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• 2000

Current seismic design codes for building structures are based on the methods which can provide enough capacity to satisfy objected performance level and exactly evaluate the seismic performance of buildings. Pushover analysis of fast becoming an accepted method for the seismic evaluation of building structures. The popularity of this approximate, nonlinear static analysis method is due to its conceptual simplicity and ability to graphically describe a capacity and demand of structure. However, some of the shortcomings of the pushover analysis, especially for longer period and irregular buildings, is the inability of method to identify failure mechanisms due to effects of higher modes. In this paper proposed lateral load pattern which includes the contribution of higher modes of vibration for irregular building structure and compared to seismic response obtained by time history.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.375-382
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• 2005

In this paper, a practical control method of wind-induced vibration of high-rise buildings is presented in the form of resizing algorithm. In the structural design process for high-rise buildings, the lateral load resisting system for the building is more often determined by serviceability design criteria including wind-induced vibration level. Even though many drift method have been developed in various forms, no practical design method for wind induced vibration has been developed so far. Structural engineers rely upon heuristic or experience in designing wind induced vibration. The performance of the proposed method is evaluated by comparing wind-induced vibration levels estimated both from approximate techniques and wind tunnel test.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.1
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• pp.9-17
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• 2006

This paper deals with a discrete simulation optimization method for designing a complex probabilistic discrete event simulation. The developed algorithm uses the configuration algorithm that can change decision variables and the stopping algorithm that can end simulation in order to satisfy the given objective value during single run. It tries to estimate an auto-regressive model for evaluating correctly the objective function obtained by a small amount of output data. We apply the proposed algorithm to M/M/s model, (s, S) inventory model, and known-function problem. The proposed algorithm can't always guarantee the optimal solution but the method gives an approximate feasible solution in a relatively short time period. We, therefore, show the proposed algorithm can be used as an initial feasible solution of existing optimization methods that need multiple simulation run to search an optimal solution.

• Journal of Korean Society for Quality Management
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• v.23 no.4
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• pp.74-89
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• 1995

In recent years, the safety of customers and the demand for rights to be protected from the risk have become stronger than ever day by day, and the function concerning product liability(PL) and quality assurance(QA) has been emphasized. Basically these functions can be obtained by inspection and there is the single rectifying sampling inspection for attribute (KSA-3105) as an existing method. But we can not say this method is good enough because of limitations in the range of applications and the approximate design of inspection methods which can not meet the rapidity and accuracy of quality information transfer according to the maturity of information period. Therefore, in this paper, a new algorithm is developed which can design the accurate inspection method by using the linear cost function that has not been considered in the existing inspection methods. Also in addition to this, a optimal rectifying sampling inspection plan, contributing to minimize the total costs, can be developed by programming the algorithm developed in this study and it can be applied to any field having many processes almost limitlessly.

• Transactions of the Korean Society of Mechanical Engineers
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• v.1 no.3
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• pp.141-145
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• 1977

In this paper, approximate solutions of the von Karman equations for the free flexural vibration of a transversely isotropic thin rectangular plate with two simply supported edges and two clamped edges are obtained. Applying one term Ritz-Galerkin procedure, the spatial dependent part of the equation is separated and time dependent function is found to be the Duffing's equation. Then the relation between nonlinear period and amplitude of the vibration is obtained by using averaging method which is a method of the perturbation procedure. It can be seen that averaging method is easy and agrees well with prior results.

• Journal of Pharmaceutical Investigation
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• v.34 no.5
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• pp.379-383
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• 2004

Statistical interpretations in a bioequivalence trial are considered and studied when the missing observations occurred in $2\;{\times}\;2$ crossover experiment. Patel (1985) suggested the approximate test procedures for carryover effect and drug effect in $2\;{\times}\;2$ crossover design when some of data are missing in the second period. A modified Patel method is newly proposed to the bioequivalence trial and it is compared with the current method through the simulation study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.88-93
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• 2015

Among other various aspects of safety culture, this research has considered safety culture from the view of aviation. A tool to examine aviation safety culture has been developed on the basis of Global Aviation Safety Network's safety culture survey. Using this tool, the degree of perception of Korean national carriers' pilots in safety culture has been examined three times for the period from 2002 to 2015. Compared to an initial result of the survey in 2002, results in 2008 and 2015 demonstrate that safety culture among pilots has rapidly changed from negative and bureaucratic to positive. Hence, it is expected that positive index of safety culture will increase 28% (total approximate 90%) in 2020.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.397-400
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• 2007

In an open reduction of the mandibular angle fracture, it is crucial to approximate each fracture segment as closer as possible for the reduction of the healing period. In this case report, we proposed a new technique for the mandibular angle fracture. This was designed to minimize the gap between two separated segments using mini-implants and surgical wires. Mini-implants were placed around the fracture line, followed by wire ligation to minimize the fracture gap. And then internal fixation was easily employed with plates and screws. The advantages of this technique were reduced time for operation, the promotion of healing, rapid functional recovery, and few complications.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.225-228
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• 1992

The purpose of this project is the presentation of new method for selection of a scalar control of linear time-periodic system. The approach has been proposed by Radziszewski and Zaleski [4] and utilizes the quadratic form of Lyapunov function. The system under consideration is assigned either in closed-loop state or in modal variables as in Calico, Wiesel [1]. The case of scalar control is considered, the gain matrix being assumed to be at worst periodic with the system period T, each element being represented by a Fourier series. As the optimal gain matrix we consider the matrix ensuring the minimum value of the larger real part of the two Poincare exponents of the system. The method, based on two-step optimization procedure, allows to find the approximate optimal gain matrix. At present state of art determination of the gain matrix for this case has been done by systematic numerical search procedure, at each step of which the Floquet solution must be found.