• Communications of the Korean Mathematical Society
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• v.29 no.1
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• pp.97-108
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• 2014

In the theory of special functions, it is important to study some formulae describing hypergeometric functions with other hypergeometric functions. In this paper, we give some methods to obtain a lot of decomposition formulae for generalized hypergeometric functions.

• Journal of the Korean Mathematical Society
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• v.40 no.4
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• pp.629-639
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• 2003

We give results describing behavior of regions of holomorphic extension of CR functions near boundary points of their domain of definition.

• Journal of the Chungcheong Mathematical Society
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• v.25 no.3
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• pp.475-489
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• 2012

A plateau in a Motzkin path is a sequence of three steps: an up step, a horizontal step, then a down step. We find three different forms for the bivariate generating function for plateaus in Motzkin paths, then generalize to longer plateaus. We conclude by describing a further generalization: a continued fraction form from which one can easily derive new multivariate generating functions for various kinds of path statistics. Several examples of generating functions are given using this technique.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.146.4-146
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• 2001

Various methods have been proposed for the time series prediction. Most of the conventional methods only optimize parameters of mathematical models, but to construct an appropriate functional form of the model is more difficult in the first place. We employ the Genetic Programming (GP) to construct the functional form of prediction models. Our method is distinguished because the model parameters are optimized by using Back-Propagation (BP)-like method and the prediction model includes discontinuous functions, such as if and max, as node functions for describing complicated phenomena. The above-mentioned functions are non-differentiable, but the BP method requires derivative. To solve this problem, we develop ...

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1741-1747
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• 2011

Though various techniques have been studied as a way of adjusting parameters of PID controllers, no perfect method of determining parameters is available to date. This paper proposes a new method for enhancing performance of PID controllers by using the characteristics of dual-input describing function (DIDF). In other words, if nonlinear elements with two inputs (DIDF) are connected in series to the plant, the critical point (-1+j0) for Nyquist stability theory can be moved to a position arbitrarily selected on the complex plane by determining necessary coefficients of the DIDF appropriately. This makes the application of the existing conventional PID parameter tuning methods a lot easier, and stability and robustness of the system are improved simultaneously due to the DIDF inserted.

• Journal of Information Science Theory and Practice
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• v.9 no.4
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• pp.1-14
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• 2021

Library communities face many problems and limitations in describing alternative format materials based on the traditional MAchine Readable Cataloging (MARC) structure. To address these problems, this research proposes an XML-based descriptive metadata framework that establishes general but fundamental bibliographic aspects of various alternative format materials by providing core elements that are essential in describing these materials. Different from existing bibliographic structures, the proposed metadata framework can represent a fundamental descriptive structure by establishing four upper-level categories, 17 core elements, and 10 sub-elements in a hierarchical structure optimized to alternative format materials. By using this principal descriptive structure, the proposed metadata framework can guide different institutions in the creation of bibliographic records for these materials in a consistent way. It is also expected to address the difficulties in describing alternative format materials in library communities and enhance the information accessibility of individuals with various types of disabilities. In addition, the proposed metadata framework is an alternative approach which functions as a mediator between heterogeneous characteristics of alternative format materials and the existing bibliographic structures in library communities.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.747-757
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• 2005

A physical variable is customarily thought of as a function. Another way of describing a physical variable is to specify it as a functional, whose special type is called a distribution. It turns out that the distribution concept provide a better mechanism for analyzing certain physical phenomena than does the function concept. By using wavelets with high regularity we give a resolution of functions with slow growth.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.229-234
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• 1998

We study on a terrain contour matching algorithm using Radial Basis Functions(RBFs) for aided inertial navigation system for position fixing aircraft, cruise missiles or re-entry vehicles. The parameter optimization technique is used for updating the parameters describing the characteristics of an area with modified Gaussian least square differential correction algorithm and the step size limitation filter according to the amount of updates. We have applied the algorithm for matching a sampled area with a target area supposed that the area data are available from Radar Terrain Sensor(RTS) and Reference Altitude Sensor(RAS)

• International Journal of Control, Automation, and Systems
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• v.6 no.3
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• pp.394-400
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• 2008

A known nonlinear compensator design approach is adapted to allow design of nonlinear lead and/or lag compensators, and a number of MATLAB functions are developed that automate the compensator design procedure. With this design tool, control engineers would be able to rapidly design nonlinear lead and/or lag compensators. An example of a tutorial nature is presented.

• Journal of Power Electronics
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• v.17 no.4
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• pp.884-891
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• 2017

The improved transfer functions of the modified Sheppard-Taylor (MS-T) converter, which is capable of regulating output voltage under a wide range of input voltage and load variations, negligible current ripple, and fewer components in comparison to the Sheppard-Taylor (S-T) converter, operating in continuous conduction mode (CCM) are investigated in this study. Its DC equilibrium point, small signal model, and transfer functions are derived and analyzed. Then, the voltage controller is applied for this MS-T converter. The comparisons between the derived model and the existing model are presented. The hardware circuit is designed and the circuit experiments are provided for validation. The results show that the improved transfer functions of the MS-T converter are more effective and general than the previous ones for describing its real characteristics.