Ryul Kim

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It is well known that Stickelberger-Swan theorem is very important for determining reducibility of polynomials over a binary field. Using this theorem it was determined the parity of the number of irreducible factors for some kinds of polynomials over a binary field, for instance, trinomials, tetranomials, self-reciprocal polynomials and so on. We discuss(More)
Various results on parity of the number of irreducible factors of given polynomials over finite fields have been obtained in the recent literature. Those are mainly based on Swan's theorem in which discriminants of poly-nomials over a finite field or the integral ring Z play an important role. In this paper we consider discriminants of the composition of(More)
Stiff-person syndrome (SPS) is a rare disorder, characterized by progressive fluctuating muscular rigidity and spasms. Glutamic acid decarboxylase (GAD) antibody is primarily involved in the pathogenesis of SPS and SPS is strongly associated with other autoimmune disease. Here we report three cases of patients with classical SPS finally confirmed by high(More)
Dear Editor, Prosopometamorphopsia (PM) is the visual distortion of face perception, which is generally accompanied by other types of visual illusions. It is mainly associated with the fusiform face area and the adjacent occipital face area. There are rare reports of PM in patients with stroke, epilepsy, tumor, and migraine, and also in patients with eye(More)
A. Silverberg (IEEE Trans. Inform. Theory 49, 2003) proposed a question on the equivalence of identifiable parent property and traceability property for Reed-Solomon code family. Earlier studies on Silverberg's problem motivate us to think of the stronger version of the question on equivalence of separation and traceability properties. Both, however, still(More)
Numerous results on self-reciprocal polynomials over finite fields have been studied. In this paper we generalize some of these to a-self reciprocal polynomials defined in [4]. We consider the properties for the divisibility of a-reciprocal polynomials, estimate the number of all nontrivial a-self reciprocal irreducible monic polynomials and characterize(More)
In this paper we investigate the separation properties and related bounds of some codes. We tried to obtain a new existence result for $(w_1, w_2)$-separating codes and discuss the"optimality"of the upper bounds. Next we tried to study some interesting relationship between separation and existence of non-trivial subspace subcodes for Reed-Solomon codes.