• 대한수학교육학회지:학교수학
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• 제11권2호
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• pp.243-260
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• 2009

이 연구에서는 예비중등교사들이 수학화를 실제적으로 경험하도록 일반화된 피보나치수열의 일반항을 구하는데 유용한 공식을 찾고, 연속하는 두 항의 비율에 대한 극한을 탐구하는 교수단원을 설계한다. 예비중등교사들은 이 교수단원을 통해 자연수 n의 Fm형 k-분할의 수 F(n, m; k)를 조합으로 표현하는 과정을 탐구함으로써 일반화된 피보나치수열의 각 항을 구하는 공식을 찾을 수 있다. 이러한 공식을 CAS형 그래핑 계산기에 직접 넣어 구체적인 피보나치수를 구할 수 있고, 일반화된 피보나치수열의 연속하는 두 항의 비율로 얻어지는 수열이 수렴한다는 추측을 할 수 있게 해 준다. 이러한 사실을 바탕으로 일반형의 피보나치수열의 연속하는 항의 비율로 만든 수열의 극한에 대해 논한다. 이 교수단원을 통해 예비중등교사들은 중복조합, 조합, 포함과 배제의 원리, 연속함수의 중간값의 정리, 이차방정식 및 삼차방정식의 해법을 되새기고 이를 활용하여 수학을 발명하는 경험을 할 수 있다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제5권1호
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• pp.21-39
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• 2001

This study is to develop assessment framework, test items and questionnaire for the National Assessment of Educational Achievement(NAEA), which administered in the elementary and secondary schools across the country in this year(2000). According to the first year study result of the NAEA, the test was administered in two core subjects, Mathematics and Social Studies. In this study, test items and sets of questionnaire and administered pretest were developed in the last year. In this year, the NAEA was administered with the adjusted test items and questionnaires and the results was analyzed and would be reported to the public. NAEA was developed on the basis of national curriculum, especially of the nature and objectives of subject curriculum in Mathematics (and also Social Studies). In the framework of assessment, we set up four differentiated levels of student achievement:‘under basic’,‘basic’,‘intermediary’, and ‘advanced’. Here ‘the intermediary level’means the level of educational achievement in which students can understand average content of subject curriculum. ‘Advanced level ’indicates the level of educational achievement in which students master all the content of subject curriculum and apply basic concepts and principles to a variety of situations. ‘The basic level’means the level of educational achievement in which students do not achieve the intermediary level. Students who do not understand average content of subject curriculum are classified as belonging to the basic level. Finally, this study would explain how to administer and analyze the test int he future. The test result was analyzed to report students’s educational achievement according to regions, content area, behavioral characteristics, and etc. This study would show how to report test results and how to set up student’s academic achievement.

• 한국수소및신에너지학회논문집
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• 제19권5호
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• pp.403-409
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• 2008

Polymer electrolyte membrane fuel cell (PEMFC) is very interesting power source due to high power density, simple construction and operation at low temperature. But it has problems such as high cost, improvement of performance, effect of temperature and initial start at low temperature. These problems can be approached to be solved by using experiment and mathematical method which are general principles for analysis and optimization of control system for heat and hydrogen detecting management. In this paper, insulation vessel and control system for stable operation of fuel cell at low temperature were developed for experiment. The constant temperature capability and the heating time at sub-zero temperatures with insulation control system were studied by using a heating bar of 60W class. PEMFC stack which was made by 4 cells with $50\;mc^2$ active area in each cell is a thermal source. Times which take to reach constant temperature by the state of insulation vacuum were measured at variable environment temperatures. The test was performed at two conditions: heating mode and cooling mode. Constant temperature capability was better at lower environment temperature and vacuum pressure. The results of this experiment could be used as basis data about stable operation of fuel cell stack in low temperature zone.

• 수산경영론집
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• 제34권1호
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• pp.137-156
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• 2003

Increasingly, leisure time is being used for outdoor recreational activities, and fishing is one of the principal forms of marine recreation. Marine recreational fishing is a popular activity in Korea and this activity has led to the development of a sector of substantial social and economic value. Also it is considered as one of the important outdoor leisure industries in Korea. With rising of income level and development of marine outdoor leisure industries, social, economic demand increase of marine recreational fishing are showing us new advance ability of marine aquatic bio-industry. However the recreational use of fish stocks has become an important consideration in the public and environmental economic analysis of management aspect of fishing, having grown considerably over recent years to reach a level in Korea where the fish stocks and coastal ecosystem has become a significant management problem. we are inevitably facing marine environmental deterioration and overfishing in marine recreational fishing. In this study, not only resources and environmental problems which are occurred by recreational fishers, but also illegal fishing behaviors and other problems such as market's failure are going to analyze basic management theories and methods of recreational fishing through mathematical principals and economic rents which maximize net social benefits. In view of the likelihood of marine recreational fishers adopting high rates of discount, the conservation of fish resources would appear to require continual public surveillance and control of the physical yield and condition of the fish stocks and the optimal use level. The institutional management of recreational fisheries is the way of escaping the collapse of recreational fisheries just like as the situation of management's failure of commercial fisheries worldwide. One of the effective management measure is a license system. In this system, optimal fee is paid by recreational fishers, which prevent them from overfishing, environmental problems to some extents and carry out the optimal number of outings. And money obtained by license fee should be spent for more improvement fishing culture and welfare for marine recreational fishing. Marine recreational fishing is to be promoted under sound conservation and management principles.

• Structural Engineering and Mechanics
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• 제53권2호
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• pp.205-226
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• 2015

Finite element method (FEM) is an effective quantitative method to solve complex engineering problems. The basic idea of FEM for a complex problem is to be able to find a solution by reducing the problem made simple. If mathematical tools are inadequate to obtain precise result, even approximate result, FEM is the only method that can be used for structural analyses. In FEM, the domain is divided into a large number of simple, small and interconnected sub-regions called finite elements. FEM has been used commonly for linear and nonlinear analyses of different types of structures to give us accurate results of plane stress and plane strain problems in civil engineering area. In this paper, FEM is used to investigate stress analysis of a shear wall which is subjected to concentrated loads and fundamental principles of stress analysis of the shear wall are presented by using matrix displacement method in this paper. This study is consisting of two parts. In the first part, the shear wall is discretized with constant strain triangular finite elements and stiffness matrix and load vector which is attained from external effects are calculated for each of finite elements using matrix displacement method. As to second part of the study, finite element analysis of the shear wall is made by ANSYS software program. Results obtained in the second part are presented with tables and graphics, also results of each part is compared with each other, so the performance of the matrix displacement method is demonstrated. The solutions obtained by using the proposed method show excellent agreements with the results of ANSYS. The results show that this method is effective and preferable for the stress analysis of shell structures. Further studies should be carried out to be able to prove the efficiency of the matrix displacement method on the solution of plane stress problems using different types of structures.

• 한국학교수학회논문집
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• 제4권1호
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• pp.91-101
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• 2001

Nowadays the number of students that is losing their interest as well as learning desire in mathematics is increasing because of lack of logical thought creative power and abstract expression that present-day mathematics requires by reason of discrepancy of extreme scholastic ability by speciality of mathematics. In these conditions, we reduce the number of learning depression by bringing about learning desire or learning interest on mathematics, and students learn effective learning methods to be voluntary learning of discovery themselves that studies basic concepts, principles, rules through logical thought of students to solve difference of scholastic ability, thus we assumed that debate studies through small group activities in ability group would be one of ways to improve learning power, so the results of our research are as follows; 1. Debate studies through small group activities were very effective because of reinforcing the achivement level of students. 2. By this learning method, an individual or cooperrative learning was fostered, and lively discussions were accomplished. And learning attitudes of students were changed by the extension of cooperative learning abilities through advices or by themselves. 3. A personal opinion is payed regard by accepting an individual idea in the process of making questions. Learners can correct wrong concepts in the process of correcting wrong answers. So if we apply above-mentioned studies with easy contents from the lower grades, the effectiveness would increase as learners go to the higher grade. According to the results of various researches as follows; "The teaching-learning method oriented coopperative debate studies is effective to find solutions to mathematical problems." If small group activities are applied in the educational situation to search the course of a desirable cooperation learning through small group activities to improve scholastic abilities for a discoverable problem-solving power. I think that the teaching-learning method oriented cooperative debate studies is one of the most desirable methods to increase the problem-solving ability.

• 한국초등수학교육학회지
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• 제15권3호
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• pp.579-598
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• 2011

본 연구에서는 2007 초등학교 수학과 교육과정과 2011 초등학교 수학과 교육과정을 비교 분석하였다. 첫째로, 2011 교육과정에서 취급하지 않게 된 학습 내용에 관해 비판적으로 논의했다. 둘째로, 2011 교육과정의 학습 내용에서 찾을 수 있는 두드러진 특정을 찾았다. 차기 교육과정의 개발에 도움이 될 수 있도록, 이러한 결과로부터 얻을 수 있었던 다음의 세 가지를 결론으로 제시하였다. 첫째, 교육과정 개발 절차를 보완할 필요가 있다. 공청회 시안 개발 및 최종 교육과정 개발 과정은 어디에도 드러나 있지 않다. 교육과정의 개발과 연구를 위해서는 이 과정을 잘 정리하여 공개할 필요가 있다. 둘째, 교육과정에서의 진술 방식을 수정 보완하는 것이 필요하다. 의미가 충분히 확립되지 않은 표현이나 모호한 표현은 어느 정도 규정하고 사용하는 것이 필요하다. 셋째, 학습 내용별 성취 기준의 진술이 일관적일 필요가 있다. 성취 기준 진술의 원칙을 설정하는 것이 필요하다. 넷째, 초등학교 교육과정과 중학교 교육과정 사이의 연계가 잘 이루어지고 있는지 검토하는 것이 필요하다.

• 한국정보처리학회논문지
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• 제3권3호
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• pp.449-459
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• 1996

본 논문의 퍼지 수리 형태학의 새로운 정의와 신경망을 이용한 이의 구현을 소개 함에 주 목적을 두고 있다. 이 새로운 정의에는 generalized-mean연산자가 중요한 역할을 하고 있다. 본 정의는 신경망을 이용한 구현에 매우 적합할. 연결자 공유 (shared-weight) 신경망의 전반부는 수리 형태적 연산을 수행하기에 적합한 구조를 가 지고 있다. 이 연결자 공유 신경망은 퍼지 수리형태학적 연산을 이용하여 추출 된 특성 정보를 근거로 하여 형태 분류를 수행한다. 따라서, 본 퍼지 정의의 파라 미터들은 신경망의 학습기법을 이용하여 최적화를 기할수 있다. 구조소들(structuring gelements), membership의 값, 그리고 가중 요소(weighting factor)들을 결정하기 위한 학습방법 (learning rule)들이 자세히 열거되어 있다. 적용 예로서 필기체 숫자 인식 문제에 응용한 결과, 퍼지수리 형태학을 이용한 신경망은 이 문제에 있어 현존하는 최고의 결과들과 충분히 견줄만한 결과를 보여주고 있다.

• 대한조선학회논문집
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• 제59권3호
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• pp.173-182
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• 2022

The present study suggests a procedure of establishing a ship dynamics modeling by regression of free-running model test results. The hydrodynamic force and moment of the whole model ship is derived from the low-pass filtered acceleration in the turning circle and zigzag maneuver tests. Force and moment of the propeller and rudder are separated from that of the whole ship to acquire the hull force and moment terms, based on the principles of the component model. The low-pass filter frequency is verified in prior to dynamics modeling, to find the threshold frequency of 2.5 Hz. The dynamics modeling of the hull is compared with the component modeling by captive model tests. Because of strong correlation between sway velocity, yaw angular velocity, and heel angle, each maneuvering coefficient is not able to be validated, but the whole modeling shows good agreement with the captive model tests.

• 정보보호학회논문지
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• 제33권2호
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• pp.183-191
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• 2023

암호 알고리즘은 많은 연산 자원을 요구하며 복잡한 수학적 원리를 통해 보안성을 가진다. 하지만 대부분의 사물인터넷 기기는 가용 자원이 한정적이며 그에 따라 연산 성능이 부족하다. 따라서 연산량을 적게 사용하는 경량암호가 등장하였다. 미국 국립표준기술연구소는 경량암호 표준화 공모전을 개최하여 경량암호의 원활한 보급을 꾀했다. 공모전의 알고리즘 중 하나인 TinyJAMBU는 순열 기반의 알고리즘이다. TinyJAMBU는 키 스케줄을 거치지 않는 대신 많은 순열 연산을 반복하며, 이때 시프트 연산이 주로 사용된다. 본 논문에서는 8-bit AVR 프로세서상에서 경량암호 TinyJAMBU를 고속 최적 구현하였다. 제안 기법은 시프트 연산을 반대 방향으로 하여 시프트 횟수를 최소화한 리버스 시프트 기법과 키와 논스가 고정인 환경에서 일부 연산을 사전 연산한 기법이다. 제안 기법은 순열연산에서 최대 7.03배, TinyJAMBU 알고리즘에 적용 시 최대 5.87배 성능 향상을 보였다. 키와 논스가 고정인 환경에서는 TinyJAMBU의 알고리즘이 최대 9.19배만큼 성능이 향상되었다.