• 한국생산제조학회지
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• 제8권3호
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• pp.66-75
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• 1999

This paper is concerned with a analysis of noise by inverse problem available for analyzing the two and three-dimensional acoustic field problems. The noise of analysis considered in this study can be reduced to an optimum problem to find the optimal set of parameters defining the vibrating state of noise source surfaces. The optimal set of parameters are searched by the standard optimization procedure minimizing the square sum of the residuals between the measured and computed quantities of sound pressure at some points in the acoustic field. Computation is carried out for typical examples in which the noise sources are located on the infinite plane. It is demonstrated that the noise of analysis can be effectively made by using the sensitive reference data.

• East Asian mathematical journal
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• 제29권2호
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• pp.207-239
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• 2013

This research is a study on student's understanding fundamental concepts of mathematical curriculum, especially in geometry domain. The goal of researching is to analyze student's concepts about that domain and get the mathematical teaching methods. We developed various questions of descriptive assessment. Then we set up the term, procedure of research for the understanding student's knowledge of geometric figures. And we analyze the student's understanding extent through investigating questions of descriptive assessment. In this research, we concluded that most of students are having difficulty with defining the fundamental concepts of mathematics, especially in geometry. Almost all the students defined the fundamental conceptions of mathematics obscurely and sometimes even missed indispensable properties. And they can't distinguish between concept definition and concept image. Prior to this study, we couldn't identify this problem. Here are some suggestions. First, take time to reflect on your previous mathematics method. And then compile some well-selected questions of descriptive assessment that tell us more about student's understanding in geometric concepts.

• 한국기계가공학회지
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• 제3권4호
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• pp.7-12
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• 2004

Inspection and analysis are essential process to determine whether a completed product is in given specification or not. Analysis of products with very complicated shape is difficult to carry out direct comparison between inspected coordinate and designed coordinates. So process called as matching or registrations is needed to solve this problem. By defining error between two coordinates and minimizing the error, registration is done. Registration consists of translation, rotation and scale transformations. Error must be defined to express feature of inspected product. In this paper, registration algorithm is developed to determine pose of sub-frame at assembly with body of automobile by defining error between two coordinates considering geometric feature of sub-frame.

• Journal of applied mathematics & informatics
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• 제5권3호
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• pp.585-596
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• 1998

Some new problems of the theory of the finite automata are considered. Applying the finite automata in various tasks of the formal languages theory is observed. Special proof of Kleene's theorem is obtained. This proof is used for the defining the star-height of the finite automaton. The proper-ties of the last object are considered. The star-height of the finite automaton is used for reformulating the star-height problem of regular expression for finite automata. The method of the reduction of the star-height problem to the task of making special finite automaton is obtained. This reformulating can help to solve the star-height problem by new way.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.399-409
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• 2007

In this paper we use iterative dynamic programming in the discrete case to solve a wide range of the nonlinear equations systems. First, by defining an error function, we transform the problem to an optimal control problem in discrete case. In using iterative dynamic programming to solve optimal control problems up to now, we have broken up the problem into a number of stages and assumed that the performance index could always be expressed explicitly in terms of the state variables at the last stage. This provided a scheme where we could proceed backwards in a systematic way, carrying out optimization at each stage. Suppose that the performance index can not be expressed in terms of the variables at the last stage only. In other words, suppose the performance index is also a function of controls and variables at the other stages. Then we have a nonseparable optimal control problem. Furthermore, we obtain the path from the initial point up to the approximate solution.

• International Journal of Automotive Technology
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• 제8권1호
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• pp.39-48
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• 2007

This paper addresses the problem of period and priority assignment in networked control systems (NCSs) using a fixed priority scheduler. The problem of assigning periods and priorities to tasks and messages is formulated as an optimization problem to allow for a systematic approach. The temporal characteristics of an NCS should be considered by defining an appropriate performance index (PI) which represents the temporal behavior of the NCS. In this study, the sum of the end-to-end response times required to process all I/Os with precedence relationships is defined as a PI. Constraints are derived from the task and message deadline requirements to guarantee schedulability. Genetic algorithms are used to solve this constrained optimization problem because the optimization formulation is discrete and nonlinear. By considering the effects of communication, an optimum set of periods and priorities can be holistically derived.

• 한국경영과학회지
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• 제22권3호
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• pp.59-80
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• 1997

Designing highly survivable interoffice telecommunication networks is considered. The problem is formulated as a minimum-cost network design problem with three node connectivity constraints. These valid and facet-defining inequalities for the convex hull of the solution are presented. A branch and cut algorithm is proposed based on the inequalities to obtain the optimal solution. With the lower bound by the cutting plane algorithm, a delete-ink heuristic is proposed to otain a good upper bound in the branch and bound procedure. The effeciveness of the branch and cut algorithm is demonstrated with computational results for a variety of problem sets : different lower bounds, two types of link costs and large number of links. The cutting plane procedure based on the three inequalities provides excellent lower bounds to the optimal solutions.

• 한국학교수학회논문집
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• 제18권4호
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• pp.371-385
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• 2015

현행 수학과 교육과정이나 교과서에서는 도형의 넓이와 부피가 무엇을 의미하는 용어인지 명료하게 정의하지 않으며, 넓이와 부피 측정에 어떤 공리가 전제되어 있는지 파악하기도 어렵다. 본고에서는 도형의 넓이와 부피 개념에 전제된 공리가 무엇인지 살펴보고, 이들 공리의 관점에서 학교수학에서의 넓이 및 부피 관련 내용 중 특히 삼각형의 넓이와 삼각뿔의 부피 공식에 대한 설명 방식의 차이점을 힐베르트의 세 번째 문제와 관련지어 논의한다.

• International Journal of Advanced Culture Technology
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• 제9권1호
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• pp.162-167
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• 2021

The aim of this paper is to analyze the development of effective online Problem-Based Learning (PBL) and Project-Based Learning (PjBL). The collaborative PBL/PjBL become one of the hot issues with the rapid growth of online learning in the era of COVID-19. Educators try to get innovative to continue instruction without sacrificing student engagement, thus adopting an instructional model of PBL/PjBL. The PBL process involves clarifying terms, defining complex problems, brainstorming, structuring and hypothesis while PjBL includes project-planning, implementation, communicating the results of a project in a presentation and evaluations with immediate individually tailored feedback within a predetermined period. Despite the differences between online and offline learning, the benefits of learning online or offline are practically the same if enough bidirectional interactions between instructors and students are possible. We argue that online qualifications are just the same as those of offline ones in PBL/PjBL models, therefore, the standards of online/offline learning are identical since education is a two-way communication.

• 한국정책학회보
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• 제21권4호
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• pp.199-228
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• 2012

정책문제는 정책과정에 참여하는 이해관계자들의 다양성 때문에 복잡성을 띄게 된다. 그러나 문제해결의 첫 단추로서 정책문제의 정확한 정의에 대한 중요성에도 불구하고, 실증주의적 접근에 따라 크게 부각되지 못한 것이 사실이다. 이에 따라 본 연구는 다양한 정책이해관계자들이 존재하며, 최근 정책문제로서 다양한 해석이 나오고 있는 IT 정책분야를 대상으로 문제구조화를 통한 정책문제 경계분석을 실시하였다. 이를 위하여 이명박 정부 출범이후부터 올해 7월까지 IT 전문 신문과 두 개의 일간지를 자료수집 대상으로 IT 산업정책 관련 모든 기사를 검색하여, 이 중 특정 인물이 IT 산업관련 정책문제를 언급한 것을 분석함으로서 IT 정책문제의 경계를 분석하였다. 분석결과 총 1908명의 이해 관계자로부터 총 2614개의 문제가 도출되었고, 이중 겹치지 않는 문제의 수(정책문제의 경계)는 369개로 나타났고, 이는 323명 정도의 이해관계자로부터 문제를 도출하면 정책 문제가 포화함을 의미한다. 세분화된 IT 산업관련 정책문제 중 가장 높은 비중을 차지하였던 것은 정부정책관련이었으며, 특히 현 정부의 IT 산업정책의 실패 및 제도적인 측면(컨트롤 타워의 부재) 등이 가장 핵심적인 정책문제로 부각되었다. 한편 이러한 IT 산업 정책문제구조화를 통한 정책문제 경계분석 결과를 기존의 논의들과 비교분석한 결과 현정부 이전부터 지속되어왔던 정책문제들이 아직까지 해결되지 못하고 지속되고 있음을 알 수 있었다. 그러나 도출된 정책문제를 세부적으로 살펴보았을 때, 정부의 문제만은 아니고, 시장에서의 기업들에 의한 정책문제의 심각성 역시 매우 큰 것으로 나타났다. 따라서 정책문제 경계에 따른 정책문제를 분석할 때, 전반적인 차원에서 문제의 경중에 따라 정책문제를 단순화시켜버리면 또 다른 제3종 오류가 범해질 수 있음을 명심해야 할 것이다.