• Bulletin of the Korean Mathematical Society
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• v.61 no.1
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• pp.135-145
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• 2024

We consider a function-field analogue of Dirichlet series associated with the Goldbach counting function, and prove that it can, or cannot, be continued meromorphically to the whole plane. When it cannot, we further prove the existence of the natural boundary of it.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.3
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• pp.258-261
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• 2005

The Preisach model needs a distribution function or Everett function to simulate the hysteresis phenomena. To obtain these functions, many experimental data obtained from the first order transition curves are usually required. In this paper, a simple procedure to determine the Preisach density function using the Gaussian distribution function and genetic algorithm is proposed. The Preisach density function for the interaction field axis is known to have Gaussian distribution. To determine the density and distribution, genetic algorithm is adopted to decide the Gaussian parameters. With this method, just basic data like the initial magnetization curve or saturation curves are enough to get the agreeable density function. The results are compared with experimental data and we got good agreements comparing the simulation results with the experiment ones.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.503-508
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• 2004

This paper proposes an efficient computation method for fixed and mixed polarity Reed -Muller function vector over Galois field GF(p). Function vectors of fixed polarity Heed Muller function with single variable can be generated by proposed method. The n-variable function vectors can be calculated by means of the Kronecker product of a single variable function vector corresponding to each variable. Thus, all fixed and mixed polarity Reed-Muller function vectors are calculated directly without using a polarity function vector table or polarity coefficient matrix.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.56-58
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• 1996

The Preisach model needs a density function to simulate the hysteresis phenomena. To obtain this function, many experimental data obtained from the first order transition curves are required to get accurate density function. However, it is difficult to perform this procedure, especially for the hard magnetic materials. In this paper, we compare the density function obtained from the experimental data with that computed from the mathematical function like the Gaussian function, and propose a simple technique to get mathematical equation of the density function or Everett function which is obtained from the initial curve, major and minor loop.

• Korean Management Science Review
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• v.20 no.2
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• pp.179-196
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• 2003

Function point model is the international standard method to measure the software size which is one of the most important factors to determine the software development cost. Function point model can successfully be applied only when the detailed specification of users' requirements is available. In the domestic public sector, however, the budgeting for software projects is carried out before the requirements of softwares ere specified in detail. Therefore, an efficient function point estimation method is required to apply function point model at the early stage of software development projects. The purpose of this paper is to compare various function point estimation methods and analyse their accuracies in domestic software projects. We consider four methods : NESMA model, ISBSG model, the simplified function point model and the backfiring method. The methods are applied to about one hundred of domestic projects, and their estimation errors are compared. The results can used as a criterion to select an adequate estimation model for function point counts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.20-24
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• 2008

A bid-based pool(BBP) model is representative of energy market structure in a number of restructured electricity markets. Supply function equilibrium(SFE) models of interaction better match what is explicitly required in the bid formats of typical BBP markets. Many of the results in the SFE literature involve restrictive parametrization of the bid cost functions. In the SFE models, two parameters, intercept and slope, are available for strategic bidding. This paper addresses the realistic competition format that players can choose both parameters arbitrarily. In a fixed demand function, equilibrium conditions for generation company's profit maximization have a degree of freedom, which induces multi-equilibrium. So it is hard to choose a convergent equilibrium. However, consideration of stochastic demand function makes the equilibrium conditions independent each other based on the amount of variance of stochastic demand function. This variance provides the bidding players with incentives to change the slope parameter from an equilibrium for a fixed demand function until the slope parameter equilibrium.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1060-1065
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• 1990

In general it is difficult to determine a Liapunov function for a given asymptotically stable, nonlinear differential equations system. But, in the system with control inputs, it is feasible to make a given positive function, except for a small area, globally satisfy the conditions of the Liapunov function for the system. We call such a positive function a Liapunov-like function, and propose a method of nonlinear optimal regulator using this Liapunov-like function. We also use the periodic Liapuitov-like friction that suits the system whose equilibrium points exist periodically. The relationship between the Liapunov function and cost function which this nonlinear regulator minimizes is considered using inverse optimal method.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.93-98
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• 2006

The paper describes a method o( user feedback in order to enhance the retrieval system effectiveness. The existing fuzzification function adapting fuzzy technique has difficulty that 4 type graph is made each time user select components. In this paper, to overcome this weak point of feedback, we proposed the interaction function using gaussian function that gives different learning rate according to choice of components with same function. We suggest the most efficient dynamic interaction function based on comparison of retrieval performance according to parameter of function. And then, we will construct the efficient retrieval system.

• Journal of the Korean Mathematical Society
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• v.48 no.3
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• pp.655-667
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• 2011

A class of functions involving divided differences of the psi and tri-gamma functions and originating from Kershaw's double inequality are proved to be completely monotonic. As applications of these results, the monotonicity and convexity of a function involving the ratio of two gamma functions and originating from the establishment of the best upper and lower bounds in Kershaw's double inequality are derived, two sharp double inequalities involving ratios of double factorials are recovered, the probability integral or error function is estimated, a double inequality for ratio of the volumes of the unit balls in $\mathbb{R}^{n-1}$ and $\mathbb{R}^n$ respectively is deduced, and a symmetrical upper and lower bounds for the gamma function in terms of the psi function is generalized.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.16-16
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• 2000

This paper describes a new structure re create a pseudo Gaussian function network (PGFN). The activation function of hidden layer does not necessarily have to be symmetric with respect to center. To give the flexibility of the network, the deviation of pseudo Gaussian function is changed according to a direction of given input. This property helps that given function can be described effectively with a minimum number of center by PGFN, The distribution of deviation is represented by level set method and also the loaming of deviation is adjusted based on it. To demonstrate the performance of the proposed network, general problem of function estimation is treated here. The representation problem of continuous functions defined over two-dimensional input space is solved.