• Nuclear Engineering and Technology
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• 제29권4호
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• pp.299-309
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• 1997

The neutronic feasibility of typical Korean three-loop 900MWe class PWR core loaded with mixed oxide fuels for both annual and 18-month cycle strategies has been investigated as a means for spent fuel management. For this study, a method of determining equivalent plutonium content was developed under the equivalence concept which gives the same cycle length as uranium fuel. Optimal plutonium zoning within the MOX assembly was also designed with the aim of minimizing the peak md power. Conceptual core designs hate hen developed for equilibrium cycle with the following variations: annual and 18-month cycle, 1/3 and full MOX loading schemes, and typical and high moderation lattice. The analysis of key core physics parameters shows that in all cases considered satisfactory core designs seem to be feasible, though addition of control rod system and change in Technical Specification for soluble boron concentration are required for full MOX loading in order to meet the current design requirements.

• Journal of applied mathematics & informatics
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• 제5권1호
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• pp.73-90
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• 1998

In this paper we introduce and study a number of new classes of quasi variational inequalities. using essentially the projection technique and its variant forms we prove that the gen-eralized set-valued mixed quasivariational inequalities are equivalent to the fixed point problem and the Wiener-Hopf equations(normal maps). This equivalence enables us to suggest a number of iterative algorithms solving the generalized variational inequalities. As a special case of the generalized set-valued mixed quasi variational in-equalities we obtain a class of quasi variational inequalities studied by Siddiqi Husain and Kazmi [35] but there are several inaccuracies in their formulation of the problem the statement and the proofs of the problem the statement and the proofs of their results. We have removed these inaccuracies. The correct formulation of thir results can be obtained as special cases from our main results.

• 대한수학회논문집
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• 제22권2호
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• pp.247-258
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• 2007

In this paper a new class of system of generalized nonlinear variational inequalities involving strongly monotone, relaxed co coercive and relaxed generalized monotone mappings in Hilbert spaces is introduced and studied. Based on the projection method, an equivalence between the system of generalized nonlinear variational inequalities and the fixed point problem is established, which is used to suggest some new iterative algorithms for computing approximate solutions of the system of generalized nonlinear variational inequalities. A few sufficient conditions which ensure the existence and uniqueness of solution of the system of generalized nonlinear variational inequalities are given, and the convergence analysis of iterative sequences generated by the algorithms are also discussed.

• 대한수학회지
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• 제32권2호
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• pp.351-361
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• 1995

Let M be a complete open Riemannian manifold. When the sectional curvature $K_M$ of M is nonpositive, Gromov has defined, in his lectures [3], the ideal boundary of M, and used it to study the geometric structure of M. In a Hadamard manifold, a simply connected manifold with nonpositive sectional curvature, a point at infinity can be defined as an equivalence class of rays. He proved many interesting theorems using this definition of ideal boundary and the so-called Tit's metric on it. He also suggested a counterpart to this for nonnegative curvature case. This idea has been taken up by Kasue to study the structure of complete open manifolds with asympttically nonnegative curvature [14]. Motivated by these works, we will define an idela boundary of a general noncompact manifold M, and study its structure.

• 산업경영시스템학회지
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• 제34권2호
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• pp.30-34
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• 2011

Variable precision rough set models have been successfully applied to problems whose domains are discrete values. However, there are many situations where discrete data is not available. When it comes to the problems with interval values, no variable precision rough set model has been proposed. In this paper, we propose a variable precision rough set model for interval values in which classification errors are allowed in determining if two intervals are same. To build the model, we define equivalence class, upper approximation, lower approximation, and boundary region. Then, we check if each of 11 characteristics on approximation that works in Pawlak's rough set model is valid for the proposed model or not.

• Kyungpook Mathematical Journal
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• 제61권2호
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• pp.223-237
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• 2021

Let n be a fixed natural number. Menger algebras of rank n can be regarded as a canonical generalization of arbitrary semigroups. This paper is concerned with studying algebraic properties of Menger algebras of rank n by first defining a special class of full n-place functions, the so-called a left translation, which possess necessary and sufficient conditions for an (n + 1)-groupoid to be a Menger algebra of rank n. The isomorphism parts begin with introducing the concept of homomorphisms, and congruences in Menger algebras of rank n. These lead us to establish a quotient structure consisting a nonempty set factored by such congruences together with an operation defined on its equivalence classes. Finally, the fundamental homomorphism theorem and isomorphism theorems for Menger algebras of rank n are given. As a consequence, our results are significant in the study of algebraic theoretical Menger algebras of rank n. Furthermore, we extend the usual notions of ordinary semigroups in a natural way.

• 대한수학회논문집
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• 제39권2호
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• pp.345-352
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• 2024

We introduce a new class of bi-partition function c_k(n), which counts the number of bi-color partitions of n in which the second color only appears at the parts that are multiples of k. We consider two partitions to be the same if they can be obtained by switching the color of parts that are congruent to zero modulo k. We show that the generating function for c_k(n) involves the partial theta function and obtain the following congruences: c₂(27n + 26) ≡ 0 (mod 3) and c₃(4n + 2) ≡ 0 (mod 2).

• 정보관리연구
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• 제28권3호
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• pp.46-73
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• 1997

정보검색 시스템의 검색효율성을 높이기 위해 많은 나라에서 시소러스를 구축하여 이용하고 있다. 그러나 시소러스 구축에는 많은 시간과 비용은 물론 전문성이 요구된다. 그러므로 외국의 시소러스를 번역하여 자국어 시소러스를 구축하는 사례를 빈번하게 찾아 볼 수 있다. 이 방법을 채택하는 경우 짧은 시간에 시소러스를 구축할 수 있다는 장점은 있으나 언어적, 문화적 차이 때문에 의미상의 등가성과 의미관계를 나타내는 계층관계와 연관관계가 상호 일치하지 않는 부분이 있을 것으로 여겨진다. 그러므로 본 연구에서는 1977년에 발행된 "Thesaurus of ERIC descriptors(7th ed. 1977)" 제 7판과 이것을 대역하여 한국 교육개발원에서 발행한 "KEDI 교육시소러스(1981)"의 디스크립터들을 비교 연구하여 번역 시소러스의 구축방법에 대한 문제점을 규명하고자 하였다.

• 한국추진공학회지
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• 제14권6호
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• pp.69-78
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• 2010

고농도 과산화수소를 이용하는 1,200 N 급 이원추진제 로켓 엔진 개발을 위한 선행 연구의 일환으로 이원추진제 엔진 요소를 설계하고 실험적으로 연구하였다. 공급된 과산화수소의 분해 성능을 비교하기 위해, $MnO_2$와 Pb가 첨가된 $MnO_2$ 촉매들에 대한 실험을 하였다. 실험결과를 바탕으로, 촉매 반응기를 설계하였으며, 97.2%의 분해 효율을 얻었다. 별도의 점화원이 없이 자연점화를 이용하기 위해, 다양한 당량비에 대해 자연점화 실험을 수행하였다. 모든 실험조건에서 자연 점화를 확인하였으며, $C^*$ 효율은 90% 혹은 그 이상을 보였다. 추력측정 결과, 가장 높은 추력은 830 N을 보였으며, $C^*$ 효율과 $I_{sp}$ 효율을 같다고 가정했을 때, 진공 추력 1,035 N으로 계산되었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.156-164
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• 2010

고농도 과산화수소를 이용하는 1,200 N 급 이원추진제 로켓 엔진 개발을 위한 선행 연구의 일환으로 이원추진제 엔진 요소를 설계하고 실험적으로 연구하였다. 공급된 과산화수소의 분해 성능을 비교하기 위해, $MnO_2$와 Pb가 첨가된 $MnO_2$ 촉매들에 대한 실험을 하였다. 실험결과를 바탕으로, 촉매 반응기를 설계하였으며, 97.2%의 분해 효율을 얻었다. 별도의 점화원이 없이 자연점화를 이용하기 위해, 다양한 당량비에 대해 자연점화 실험을 수행하였다. 모든 실험조건에서 자연 점화를 확인하였으며, $C^*$ 효율은 90% 혹은 그 이상을 보였다. 추력측정 결과, 가장 높은 추력은 830 N을 보였으며, 94.1% 이론 비추력을 적용했을 경우, 진공 추력 1,035 N으로 계산되었다.