• Structural Engineering and Mechanics
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• v.25 no.1
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• pp.21-37
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• 2007

In this study a stochastic approach for linear viscous dampers design adopted for seismic protection of buildings is developed. Devices optimal placement into the main structure and their mechanical parameters are attained by means of a reliability-based optimum design criterion, in which an objective function (O.F.) is minimized, subject to a stochastic constraint. The seismic input is modelled by a non stationary modulated Kanai Tajimi filtered stochastic process. Building is represented by means of a plane shear type frame model. The selected criterion for the optimization searches the minimum of the O.F., here assumed to be the cost of the seismic protection, i.e., assumed proportional to the sum of added dampings of each device. The stochastic constraint limits a suitable approximated measure of the structure failure probability, here associated to the maximum interstorey drift crossing over a given threshold limit, related, according with modern Technical Codes, to the required damage control.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.748-750
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• 2005

This paper approaches a methodology for deciding the optimal reliability criteria for an optimal composite power system expansion planning considering generation and transmission systems simultaneously. A probabilisticreliability criterion, $LOLE_R$(Loss of Load Expectation), is used in this study. The optimalreliability criterion $LOLE_R*$ is decided at minimum cost point of total cost curve which is the sum of the utility cost associated with construction cost and the customer outage cost associated with supply interruptions for load considering forced outage rates of elements(generators and lines) in long term forecasting. The characteristicsand effectiveness of this methodology are illustrated by the case study using MRBTS size system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.7
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• pp.997-1004
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• 1990

In this paper, a design method of a robust adaptive regulator with feedfoward path based on the explicit criterion minimization is proposed. The convergence speed of parameter estimation is improved by using the stochastic Newton minimization method in the criterion minimization algorithm, and sensitivity derivatives are used in the regulator calculation for improving the robustness of the control system. Trh proposed adaptive regulator is applied to the stable minimum-phase and nonminimum-phase system, the results are shown that control performance and disturbance compensation ability of the regulator are improved. And the choosing method of input penalty is proposed.

• Journal of the Korean Statistical Society
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• v.30 no.3
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• pp.453-465
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• 2001

It is often the case that one wants to estimate parameters of the distribution which follows certain parametric model, while the dta are contaminated. it is well known that the maximum likelihood estimators are not robust to contamination. Basuet al.(1998) proposed a robust method called the minimum density power divergence estimation. In this paper, we investigate data-driven selection of the tuning parameter $\alpha$ in the minimum density power divergence estimation. A criterion is proposed and its performance is studied through the simulation. The simulation includes three cases of estimation problem.

• Journal of Plant Biology
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• v.37 no.4
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• pp.403-410
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• 1994

The taxonomic criterion between Erythroglossum and Sorella was reappraised based on Korean plants of E. minimum Okamura and S. repens (Okamura) Hollenberg. Development of the reproductive organs was observed from field collected plants as well as cultured plants. The Polyneura-tuype procarp which comprised one group of sterile cells and two carpogonial branches arising from a supporting cell was observed in both species. Distribution of tetrasporangial sori was irregular in both species, so it is not relevant to distinguish Sorella from Erythroglossum by the characteristic of tetrasporangial distribution. E. minimum and S. repens were very similar in vegetative form, but were reproductively isolated. Chromosome numbers were given as n=ca. 30 in S. repens and n=ca. 41 in E. minimum, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.209-214
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• 2003

Multi-mode coding method is a reliable DC-suppression method. There are two ways to improve the DC-suppression performance. One is improving scrambler's performance, and the other is improving selection criteria. The latter uses the MRDS(minimum running digital sum) criterion. It is easy to calculate, but its performance goes down when the length of codeword is getting longer. The MSW(mean squared weight) criterion that is known as the best so far regardless of the length of codeword has the high complexity. In this paper, we present the new selection criteria, MPRDS(minimum peak RDS) and A BSRDS(absolute RDS). Their performance are close to the MSW, implementation is simple. And also we present the SC(sign change) that has a subsidiary role with the original selection criteria and improve the capacity.

• Communications for Statistical Applications and Methods
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• v.16 no.1
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• pp.195-208
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• 2009

A conventional single design optimality criterion has been used to select an efficient experimental design. But, since an experimental design is constructed with respect to an optimality criterion pre specified by investigators, an experimental design obtained from one optimality criterion which is superior to other designs may perform poorly when the design is evaluated by another optimality criterion. In other words, none of these is entirely satisfactory and even there is no guarantee that a design which is constructed from using a certain design optimality criterion is also optimal to the other design optimality criteria. Thus, it is necessary to develop certain special types of experimental designs that satisfy multiple design optimality criteria simultaneously because these multi-optimal designs (MODs) reflect the needs of the experimenters more adequately. In this article, we present a heuristic approach to construct second-order response surface designs which are more flexible and potentially very useful than the designs generated from a single design optimality criterion in many real experimental situations when several competing design optimality criteria are of interest. In this paper, over cuboidal design region for $3\;{\leq}\;k\;{\leq}\;5$ variables, we construct multi-optimal designs (MODs) that might moderately satisfy two famous alphabetic design optimality criteria, G- and IV-optimality criteria using a GA which considers a certain amount of randomness. The minimum, average and maximum scaled prediction variances for the generated response surface designs are provided. Based on the average and maximum scaled prediction variances for k = 3, 4 and 5 design variables, the MODs from a genetic algorithm (GA) have better statistical property than does the theoretically optimal designs and the MODs are more flexible and useful than single-criterion optimal designs.

• Proceedings of the KIEE Conference
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• 1979.08a
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• pp.158-159
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• 1979

Based on minimum-mean-sqare error criterion, a noise filtering algorithm for the reconstruction of an image function from noisy projection data is suggested. The filter is constructed with a few projection data. This algorithm requires less computational time compared with other noise filtering algorithm.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.371-379
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• 2017

Modelling of a crack propagating through a finite element mesh under mixed mode conditions is of prime importance in fracture mechanics. In this paper, two crack growth criteria and the respective crack paths prediction in functionally graded materials (FGM) are compared. The maximum tangential stress criterion (${\sigma}_{\theta}-criterion$) and the minimum strain energy density criterion (S-criterion) are investigated using advanced finite element technique. Using Ansys Parametric Design Language (APDL), the variation continues in the material properties are incorporated into the model by specifying the material parameters at the centroid of each finite element. In this paper, the displacement extrapolation technique (DET) proposed for homogeneous materials is modified and investigated, to obtain the stress intensity factors (SIFs) at crack-tip in FGMs. Several examples are modeled to evaluate the accuracy and effectiveness of the combined procedure. The effect of the defects on the crack propagation in FGMs was highlighted.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2565-2571
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• 2020

Background: Understanding the behaviour of nuclear fuel claddings by conducting burst test on single cladding tube under simulated loss-of-coolant accident conditions and developing theoretical cum empirical predictive computer codes have been the focus of several investigations. The developed burst criterion (a) assumes symmetrical deformation of cladding tube in contrast to experimental observation (b) interpolates the properties of Zircaloy-4 cladding in mixed α+β phase (c) does not account for azimuthal temperature variations. In order to overcome all these drawbacks of burst criterion, it is reasoned that artificial intelligence technique may be a better option to predict the burst parameters. Methods: Artificial neural network models based on feedforward backpropagation algorithm with logsig transfer function are developed. Results: Neural network architecture of 2-4-4-3, that is model with two hidden layers having four nodes in each layer is found to be the most suitable. The mean, maximum, and minimum prediction errors for this optimised model are 0.82%, 19.62%, and 0.004%, respectively. Conclusion: The burst stress, burst temperature, and burst strain obtained from burst criterion have average deviation of 19%, 12%, and 53% respectively whereas the developed neural network model predicted these parameters with average deviation of 6%, 2%, and 8%, respectively.