• Journal of the Chungcheong Mathematical Society
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• v.26 no.1
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• pp.161-166
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• 2013

In this paper we study the infiniteness of the Hilbert 3-class field tower of imaginary cubic function fields.

• Communications of the Korean Mathematical Society
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• v.27 no.2
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• pp.223-231
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• 2012

We obtain some density results for the 4-ranks of class groups of quadratic extensions of quadratic function fields analogous to those results of F. Gerth in the classical case.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.224-229
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• 1993

The robot has spread remarkably, is used not only in manufacturing but also in various other fields, and is becoming more popular in everyday life. At the same time, the functional demands for all manner of robots have been diversified. Education regarding robots has been developing in the computer, mechanism, sensor and artificial intelligence fields. Technical education which integrates all of the above is necessary and in great demand. We have developed an educational robot so that it can be used in education in fields including structure, sensory and brain function and can also organically integrate those.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.7
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• pp.57-66
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• 2005

The Hydrological Simulation Program - FORTRAN (HSPF) was modified to simulate nonpoint pollutant loadings from paddy fields using a field experimental data collected during 2001-2002. The concept of a 'dike height' was added in a modified HSPF code, named HSPF-Paddy, to consider the function of retaining water by a weir at the field outlet. The effect of fertilization on the variances of nutrients on the soil surface and shallow soil layer was described mathematically with a Dirac delta function (or first-order kinetics). As confirmed through model verification, the HSPF-Paddy modifications were shown to represent the function of retaining water, varied ponded water, and surface runoff by forced drain during both rainy and non-rainy seasons and reasonably predicted the water balance and nutrients behavior in paddy fields. It is a distributed watershed model which, with the paddy modifications, can now simulate nonpoint pollutant loadings where paddy fields are dominant, and it can be used to evaluate the effects of paddy fields on the water quality at a basin scale, and assess the impacts of proposed BMPs applied to paddy fields.

• Bulletin of the Korean Mathematical Society
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• v.48 no.6
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• pp.1219-1224
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• 2011

In this paper we give a determinant formula for congruent zeta functions of real Abelian function fields. We also give some example of congruent zeta functions when the conductor of real Abelian function field is monic irreducible.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1965-1970
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• 2011

This paper proposes the method of switching function implementation using switching function extraction based on graph over finite fields. After we deduce the matrix equation from path number of directional graph, we propose the switching function circuit algorithm, also we propose the code assignment algorithm for nodes which is satisfied the directional graph characteristics with designed circuits. We can implement more optimal switching function compare with former algorithm, also we can design the switching function circuit which have any natural number path through the proposed switching function circuit implementation algorithms. Also the proposed switching function implementation using graph theory over finite fields have decrement number of input-output, circuit construction simplification, increment arithmetic speed and decrement cost etc.

• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.417-426
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• 2017

We explicitly determine fundamental units and regulators of an infinite family of cyclic quartic function fields $L_h$ of unit rank 3 with a parameter h in a polynomial ring $\mathbb{F}_q[t]$, where $\mathbb{F}_q$ is the finite field of order q with characteristic not equal to 2. This result resolves the second part of Lehmer's project for the function field case.

• Journal of the Chungcheong Mathematical Society
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• v.23 no.4
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• pp.699-704
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• 2010

In this paper, we prove that the Hilbert 2-class field tower of an imaginary quadratic function field $F=k({\sqrt{D})$ is infinite if $r_2({\mathcal{C}}(F))=4$ and exactly one monic irreducible divisor of D is of odd degree, except for one type of $R{\acute{e}}dei$ matrix of F. We also compute the density of such imaginary quadratic function fields F.

• Bulletin of the Korean Mathematical Society
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• v.29 no.1
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• pp.153-163
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• 1992

Carlitz module is used to study abelian extensions of K=$F_{q}$(T). In number theory every abelian etension of Q is contained in a cyclotomic field. Similarly every abelian extension of $F_{q}$(T) with some condition on .inf. is contained in a cyclotomic function field. Hence the study of cyclotomic function fields in analogy with cyclotomic fields is an important subject in number theory. Much are known in this direction such as ring of integers, class groups and units ([G], [G-R]). In this article we are concerned with the ring of integers in a cyclotomic function field. In [G], it is shown that the ring of integers is generated by a primitive root of the Carlitz module using the ramification theory and localization. Here we will give another proof, which is rather elementary and explicit, of this fact following the methods in [W].[W].

• Communications of the Korean Mathematical Society
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• v.12 no.1
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• pp.37-43
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• 1997

Some formulas of the genus numbers and the ambiguous ideal class numbers of function fields are given and these numbers are shown to be the same when the extension is cyclic.