• Journal of applied mathematics & informatics
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• v.40 no.3_4
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• pp.765-767
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• 2022

The inverse Galois problem concerns whether or not every finite group appears as the Galois group of some Galois extension of the rational numbers. This problem, first posed in the early 19th century, is unsolved. In other words, we consider a pair - the group G and the field K. The question is whether there is an extension field L of K such that G is the Galois group of L. In this paper we present the proof that any group G is a Galois group of any field extension. In other words, we only consider the group G. And we present the solution to the inverse Galois problem.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1149-1157
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• 2017

The satisfiability problem is always a core problem in artificial intelligence (AI). And how to improve the efficiency of algorithms solving the satisfiability problem is widely concerned. Algorithm IER (Improved Extension Rule) is based on extension rule. The number of atoms and the number of clauses affect the efficiency of the algorithm IER. DPLL rules are helpful to reduce these numbers. Then a complete algorithm CIER based on splitting rule and extension rule is proposed in this paper in order to improve the efficiency. At first, the algorithm CIER (Complete Improved Extension Rule) reduces the scale of a clause set with DPLL rules. Then, the clause set is split into a group of small clause sets. In the end, the satisfiability of the clause set is got from these small clause sets'. A strategy MOAMD (maximum occurrences and maximum difference) for the algorithm CIER is given. With this strategy, a better arrangement of atoms could be got. This arrangement could make the number of small clause sets fewer and the scale of these sets smaller. So, the algorithm CIER will be more efficient.

• Journal of the Korean Mathematical Society
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• v.38 no.3
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• pp.633-644
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• 2001

Revenel computed the Adams spectral sequence converging to BP(Ω$^2$S(sup)2n+1) and got the E(sub)$\infty$-term. Then he gave the conjecture about the extension. Here we prove that there should be non-trivial extension. We also study the BP(sub)*BP comodule structures on the polynomial algebras which are related with BP(sub)*(Ω$^2$S(sup)2n+1).

• Bulletin of the Korean Mathematical Society
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• v.47 no.6
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• pp.1131-1138
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• 2010

In the present paper, we evaluate an analytic formula as a solution of Susceptible Infective (SI) model problem for communicable disease in which the daily contact rate (C(N)) is supposed to be varied linearly with population size N(t) that is large so that it is considered as a continuous variable of time t. Again, we introduce some Lie group of operators to make an extension of above analytic formula of the determin-istic epidemics model problem. Finally, we discuss some of its particular cases.

• Journal of Welding and Joining
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• v.31 no.3
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• pp.39-43
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• 2013

It is difficult to feed welding wire stably, when the distance between welding wire feeder and welding torch is far enough. In order to solve this problem, arranging a extension wire feeder between them could be one of useful methods. However, the welding wire could be twisted up in the extension cable between extension and terminal wire feeders in the case that RPM of extension wire feeding motor is higher than that of terminal motor. In this study, feeding problem of normal push-pull wire feeding system occurred at low welding current range less than 250A. In order to solve the problem, two new wire feeding systems of push-pull type were introduced. Welding wire feeding tests were preformed in the range of 150A to 400A with the developed push-pull feeding system. In addition, weldability test was performed at the welding current of 200A, 300A, and 400A. The welding wire twisting problem that was observed in the normal feeding system did not occur in the new push-pull wire feeding system.

• Journal of Agricultural Extension & Community Development
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• v.5 no.1
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• pp.123-132
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• 1998

After late 1980s, new approach is needed for satisfying with people's various information needs and better quality of life on Korean extension service. The United States began modern extension service at first and has influenced many countries. Cooperative extension service has helped people practically by searching into people's problem and developing various channel to diffuse. Cooperative extension adopts changes in extension service environment and puts them to use. Based on the extension service in the United States, following recommendations were suggested; 1) carrying out extension service to meet the changing needs of people, 2) strengthening the extension function of agricultural Colleges, 3) review of cooperative agricultural research and extension, 4) developing programs and management, 5) accumulation agricultural information and utilizing them.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1359-1367
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• 2003

Through the historical and logical methodology, The historical development and extension of diagnostic concepts as chi(氣), shue(血), yin(陰), yang(陽) is analyzed. This study suggests the analystic methodology of diagnostic concepts, introduce the justification problem of oriental medical diagnosis, and is concluded with the problem of diagnostic concepts which should be modified and.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.1
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• pp.1-14
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• 2009

The efficiency of transportation requests fulfillment can be increased through extending the problem of vehicle routing and scheduling by the possibility of subcontracting a part of the requests to external carriers. This problem extension transforms the usual vehicle routing and scheduling problems to the more general integrated operational transportation problems. In this contribution, we analyze the motivation, the chances, the realization, and the challenges of the integrated operational planning and report on experiments for extending the plain Vehicle Routing Problem to a corresponding problem combining vehicle routing and request forwarding by means of different sub-contraction types. The extended problem is formalized as a mixed integer linear programming model and solved by a commercial mathematical programming solver. The computational results show tremendous costs savings even for small problem instances by allowing subcontracting. Additionally, the performed experiments for the operational transportation planning are used for an analysis of the decision on the optimal fleet size for own vehicles and regularly hired vehicles.

• Journal of the Korean School Mathematics Society
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• v.4 no.1
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• pp.125-136
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• 2001

This research is about how the adapted learning of descriptive assessment problems influence on the extension of the ability of the students. As a result, adapted learning of descriptive assessment problems totally led to positive effect, and according to the analyses of behavioral objectives divided into knowledge, comprehension and problem solving, they had more effect on the ability of students' problem solving. Learning attitude of the students were changed into self-centered learning attitude and interest on the subject of mathematics were highly increased since the research had started. If we adapt this research to the learning of mathematics after we develop various problems that can develop creativity, I'm sure that it will be a effective way for both extension of the ability and problem solving ability of the students.

• Communications of the Korean Mathematical Society
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• v.35 no.1
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• pp.137-149
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• 2020

Let γ⁽ⁿ⁾ ≡ {γ_ij} (0 ≤ i+j ≤ 2n, |i-j| ≤ n) be a sequence in the complex number set ℂ and let E (n) be the Embry truncated moment matrices corresponding from γ⁽ⁿ⁾. For an odd number n, it is known that γ⁽ⁿ⁾ has a rank E (n)-atomic representing measure if and only if E(n) ≥ 0 and E(n) admits a flat extension E(n + 1). In this paper we suggest a related problem: if E(n) is positive and nonsingular, does E(n) have a flat extension E(n + 1)? and give a negative answer in the case of E(3). And we obtain some necessary conditions for positive and nonsingular matrix E (3), and also its sufficient conditions.