• Journal of the Korean Statistical Society
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• v.16 no.2
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• pp.80-91
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• 1987

Minimum $L_i$ norm estimation is a robust procedure ins the sense that it leads to an estimator which has greater statistical eficiency than the least squares estimator in the presence of outliers. And the $L_1$ norm estimator has some desirable statistical properties. In this paper a new computational procedure for $L_1$ norm estimation is proposed which combines the idea of reweighted least squares method and the linear programming approach. A modification of the projective transformation method is employed to solve the linear programming problem instead of the simplex method. It is proved that the proposed algorithm terminates in a finite number of iterations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.1
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• pp.1-10
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• 1995

A graphic user interface for effectively browsing object-oriented databases in complex applications is designed and implemented. The rationale behind our design lies in enabling the users of various levels and needs to investigate the database according to their respective interests and desired depths. A novel idea in our design is the introduction of zooming techniques from a logical view, which vidualize the backbone abstraction concepts of the object-oriented data model. These objectives are verified by evaluating the results of its implementation.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.236-241
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• 1988

This note considers the class of controllers with integral action which arise directly from appropriate system models. Via internal model principle approach, a corresponding class of self-tuning controller is shown to have both integral action in controller and offset removal in the tuning algorithm. The key idea is to constrain the estimator in each step in order to ensure that dc gain of feedforward and feedback polynomial of adaptive controller are always equal, thus allowing the loop integrator to work properly.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.195-205
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• 2004

To the unconstrained programme of non-convex function, this article give a modified BFGS algorithm. The idea of the algorithm is to modify the approximate Hessian matrix for obtaining the descent direction and guaranteeing the efficacious of the quasi-Newton iteration pattern. We prove the global convergence properties of the algorithm associating with the general form of line search, and prove the quadratic convergence rate of the algorithm under some conditions.

• Communications for Statistical Applications and Methods
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• v.9 no.2
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• pp.325-335
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• 2002

In this paper we introduce some adaptive M-estimators using selector statistics to estimate the center of symmetric and continuous underlying distributions. This selector statistics is based on the idea of Hogg(1983) and Hogg et. al. (1988) who used averages of some order statistics to discriminate underlying distributions. In this paper, we use the functions of sample quantiles as selector statistics and determine the suitable quantile points based on maximizing the distance index to discriminate distributions under consideration. In Monte Carlo study, this robust estimation method works pretty good in wide range of underlying distributions.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.97-100
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• 2005

A new model-based clustering algorithm is proposed. The idea starts from the assumption that observations are realizations of Gaussian processes and so are correlated. With a special covariance structure, the posterior probability that an observation belongs to each cluster is computed using the ECM algorithm. A preliminary result of small-scale simulation study is given to compare with the k-means clustering algorithms.

• Proceedings of the Safety Management and Science Conference
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• 2000.11a
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• pp.203-216
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• 2000

In this paper, we Investigate rationales for feedback adjustment using some techniques associated with automatic process control based on some nonstatioary disturbance models. Feedback-control schemes are often operated so that the nature of the disturbance that is being compensated is concealed and unusual deviations from the target cannot be taken account of. In this connection feedback control schemes is useful to extend the idea of common causes and special causes to such systems. Minimum-cost feedback schemes are discussed for some simple ,but practically interesting ,models.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.211-214
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• 2005

The analytical model capable of predicting stress vs. strain relations for circular FRP-confined concrete in a rational manner is proposed. The underlying idea is that the volumetric expansion due to progressive microcracking is an important measure of the extent of damage in the material microstructure. Various existing analytical models including the proposed were also investigated, and compared each other and with test results.

• Structural Engineering and Mechanics
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• v.20 no.1
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• pp.111-121
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• 2005

The dynamic interaction of vehicle-bridge is studied by using transfer matrix method in this paper. The vehicle model is simplified as a spring-damping-mass system. By adopting the idea of Newmark-${\beta}$ method, the partial differential equation of structure vibration is transformed into a differential equation irrelevant to time. Then, this differential equation is solved by transfer matrix method. The prospective application of this method in real engineering is finally demonstrated by several examples.

• The Mathematical Education
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• v.44 no.1 s.108
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• pp.87-101
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• 2005

The purpose of this paper is to propose a teaching method which is focused on the mathematical thinking skills such as the use of induction, counter example, analogy, and so on mathematicians use when they explore their research fields. Many have indicated that students have learned mathematics exploring to use very different methods mathematicians have done and suggested students explore as they do. In the first part of the paper, the plausible whole processes from the beginning time they get a rough idea to a refined mathematical truth. In the second part, an example with Euler characteristic of 1. In the third, explaining the same processes with ${\pi}$, a model modified from the processes is designed. It is hoped that the suggested model, focused on a variety of mathematical thinking, helps students learn mathematics with understanding and with the association of exploring entertainment.