• Journal of applied mathematics & informatics
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• 제27권3_4호
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• pp.673-683
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• 2009

We point out: to make Hermtian matrices A and B satisfy Styan matrix inequality, the condition "positive definite property" demanded in the present literatures is not necessary. Furthermore, on the premise of abandoning positive definite property, we derive Styan matrix inequality of Hadamard product for inverse Hermitian matrices and the sufficient and necessary conditions that the equation holds in our paper.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권2호
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• pp.141-148
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• 2009

The article discusses roles of analysis in problem solving, especially the problem posing. The author shows the procedure of analysis like the presentation of the hypothesis, the reasoning for the necessary conditions and the sufficient condition. Finally the author suggests that the analysis should be reviewed in the school mathematics.

• 대한수학회지
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• 제46권5호
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• pp.1087-1103
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• 2009

Given a system of s independent 1-forms on a smooth manifold M of dimension m, we study the existence of integral manifolds by means of various generalized versions of the Frobenius theorem. In particular, we present necessary and sufficient conditions for there to exist s'-parameter (s' < s) family of integral manifolds of dimension p := m-s, and a necessary and sufficient condition for there to exist integral manifolds of dimension p', p' $\leq$ p. We also present examples and applications to complex analysis in several variables.

• 방사성폐기물학회지
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• 제16권2호
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• pp.203-209
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• 2018

중성자 수송방정식으로 기술되는 중성자 거동을 중성자 확산방정식으로 계산하기 위해서는 수송경계조건에 대한 정확한 확산근사가 필요하다. 본 연구에서는 수송이론의 반사 및 진공경계조건에 대한 근사로 확산계산에서 광범위하게 사용되는 영중성자류, Marshak 및 Mark, 영중성자속, Albedo 조건 등에 대하여 수송이론의 확산근사 관점에서 유도 분석하여 각 조건의 수학적, 물리적 의미를 이해하고 서로의 상관관계를 보였다. 이러한 경계조건을 갖는 대상 문제를 서로 다른 확산경계조건을 사용하여 풀어 결과를 비교하였고 이들이 수송 경계조건을 비교적 정확히 기술함을 보였다.

• 한국물환경학회지
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• 제34권3호
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• pp.339-345
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• 2018

The integrated environmental permit system is currently in operation online. It carries out various functions of postmanagement such as the submission of annual reports containing operations management data onto integrated management workplaces, the operation and management of emission facilities and prevention facilities, and the disclosure of information on the integrated permission. On the other hand, the integrated environmental permit system needs to perform various roles in order to stably manage and smoothly perform the permitting work. It is necessary to utilize this system to establish policies by using diverse operations management data onto integrated management workplaces collected in the integrated environmental permit system. This system can also play a role in improving the post-management system and user convenience after the permission review and approval processes. The integrated environmental permit system can be effectively used to set up the BAT-AEL because it collects all of the cross-media data and identifies the overall status of the workplace. In order to establish a post management system after the approval, it is necessary to provide performance management and performance evaluation functions as conditions of the permit after approval. In addition, a variety of support functions should be provided to enable the permission authority and the environmental expert examination agency to facilitate the review of permits. It will be necessary to provide an evaluation system and a proactive diagnostic function to determine whether permission conditions and permit emission standards will change in the future. Also, it is important to adopt an information exchange platform that can be used to collect the status data onto the workplaces; the platform can also be used as an information exchange site for technical working groups (TWG), and for collecting field experts' opinions.

• 대한안전경영과학회지
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• 제17권4호
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• pp.381-396
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• 2015

The study proposes multiple TRIZ contradiction solution strategies for addressing PC (Physical Contradiction) and TC (Technical Contradiction) by implementing TRIZ cause-and-effect tree. The problem associated with TC of the ends is solved by PC of means which employs a causal relationship between causes and effects. The TRIZ contradiction solution strategies demonstrated in this research are classified into 3 types of combined strategy as follows: 1. To-Be PC and AS-Is PC, 2.To-Be PC and As-Is TC, 3.As-Is PC and To-Be TC. The combined strategy of To-Be PC and As-Is PC is similar to a divide-and-conquer technique. This strategy adopts parallel strategies using 4 separation principles in time, in space, between parts and the whole, and upon condition of two reversed-PCs. Moreover, its application elucidates the conflict relationship of two TCs from the study. The integrated 4 separation principles and 40 inventive principles present an effective synergy effect from the combination, and further addresses the problems in the TRIZ contradiction resolution strategies. Combined strategy of To-Be PC and As-Is TC implements the 40 inventive principles that To-Be PC of the means resolves the As-Is TC of the ends. Combined strategy of As-Is PC and To-Be TC also uses inventive principles to the As-Is PC of the means to solve the To-Be TC of the ends. In addition, propositional and logical relationship of necessary and sufficient conditions between TC and PC is used to support the validity of 3 TRIZ contradiction solution strategies. In addition, 3 other strategies of necessary and sufficient conditions validate the contraposition relationship of the truth table. This study discusses TRIZ case studies from National Quality Circle Contest from the years between 2011 and 2014 to provide the usage guidelines of TRIZ contradiction solutions for quality purposes. Examining analysis from the case studies and investigating combined strategies allows the users to obtain comprehensive understanding.

• 소성∙가공
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• 제11권6호
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• pp.513-518
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• 2002

The equivalent boundary conditions have been applied to the front door panel forming process, in order to demonstrate its reliability and validity. The elongation in the bead forming process is applied to the binder wrap process as the equivalent displacement boundary condition and the restraining force in the drawing process is applied to stamping process as the equivalent force boundary condition. The result calculated with the equivalent boundary conditions shows closer coincidence with the experimental result than simulation with different boundary conditions. The numerical result fully demonstrates that drawbead forming simulation for calculation of equivalent boundary conditions is necessary and effective.

• 대한수학회보
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• 제44권3호
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• pp.537-545
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• 2007

Necessary conditions for the existence of common fixed points for noncommuting mappings satisfying generalized contractive conditions in the setup of certain metrizable topological vector spaces are obtained. As applications, related results on best approximation are derived. Our results extend, generalize and unify various known results in the literature.

• 대한수학회지
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• 제52권3호
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• pp.567-586
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• 2015

In this paper, we study optimal control problems for parabolic hemivariational inequalities of dynamic elasticity and investigate the continuity of the solution mapping from the given initial value and control data to trajectories. We show the existence of an optimal control which minimizes the quadratic cost function and establish the necessary conditions of optimality of an optimal control for various observation cases.

• Journal of applied mathematics & informatics
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• 제31권1_2호
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• pp.285-297
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• 2013

This paper deals with parabolic equations coupled via nonstandard growth sources, subject to homogeneous Dirichlet boundary conditions. Three kinds of necessary and sufficient conditions are obtained, which determine the complete classifications for non-simultaneous and simultaneous blowup phenomena. Moreover, blowup rates are given.