• 한국수학사학회지
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• 제30권1호
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• pp.17-29
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• 2017

This paper is concerned with the $Ces{\grave{a}}ro$ summability of Fourier series. Many authors have studied on the summability of Fourier series up to now. Also, G. H. Hardy and J. E. Littlewood [5], Gaylord M. Merriman [18], L. S. Bosanquet [1], Fu Traing Wang [24] and others had studied the $Ces{\grave{a}}ro$ summability of Fourier series until the first half of the 20th century. In the section 2, we reintroduce Ernesto $Ces{\grave{a}}ro^{\prime}s$ life and the meaning of mathematical history for $Ces{\grave{a}}ro^{\prime}s$ work. In the section 3, we investigate the classical results of summability for Fourier series from 1897 to the mid-twentieth century. In conclusion, we restate the important classical results of several theorems of $Ces{\grave{a}}ro$ summability for Fourier series. Also, we present the research minor lineage of $Ces{\grave{a}}ro$ summability for Fourier series.

• 센서학회지
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• 제28권3호
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• pp.182-186
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• 2019

When a camera is employed for 3D sensing, accurate camera calibration is vital as it is a prerequisite for the subsequent steps of the sensing process. Camera calibration is usually performed by complex mathematical modeling and geometric analysis. On the other contrary, data learning using an artificial neural network can establish a transformation relation between the 3D space and the 2D camera image without explicit camera modeling. However, a neural network requires a large amount of accurate data for its learning. A significantly large amount of time and work using a precise system setup is needed to collect extensive data accurately in practice. In this study, we propose a two-step neural calibration method that is effective when only a small amount of learning data is available. In the first step, the camera projection transformation matrix is determined using the limited available data. In the second step, the transformation matrix is used for generating a large amount of synthetic data, and the neural network is trained using the generated data. Results of simulation study have shown that the proposed method as valid and effective.

• 과학교육연구지
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• 제44권3호
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• pp.331-344
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• 2020

본 연구는 한국과 캐나다의 수학 교과서 중 수와 연산 영역을 초등학교 5, 6학년을 중심으로 비교·분석하여 한국 초등학교 수학교육과정 및 교과서 개발에 의미 있는 시사점을 찾는 데 목적이 있다. 이를 위해 한국과 캐나다 초등학교 수학과 교육과정 및 수학 교과서의 교과서 구성 체제를 비교·분석하고, 수학 교과서 수와 연산 영역의 학년별 도입 시기 및 초등학교 5, 6학년 수와 연산 영역의 학습 내용을 비교·분석하였다. 본 연구의 결론은 다음과 같다. 첫째, 학습한 수학적 개념과 연산을 사칙연산의 종류나 수학 영역에 구애받지 않고, 실생활과 밀접하게 연관된 문제 상황 속에서 자연스럽게 도입하여 통합적으로 문제를 해결할 수 있는 교과서 구성이 필요하다. 둘째, 실제 사진과 수학, 과학, 기술, 공학, 예술 등의 소재를 사용한 문항 구성 및 읽을 거리로 수학의 필요성과 유용성을 느낄 수 있도록 하는 교과서 구성이 필요하다. 셋째, 다양한 실제 교구 및 수학 모델의 사용을 통한 충분한 수학 원리 학습, 공학 도구를 사용하여 문제해결 전략에 초점을 맞춘 교과서 구성이 필요하다. 넷째, 분수와 소수 학습에 대한 학습 지도 시기나 학습 내용 구성 및 전개 방법에 대한 깊이 있는 논의가 필요하다.

• 농업과학연구
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• 제43권3호
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• pp.450-458
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• 2016

High performance small and mid-sized tractors are required for dryland and orchard operations. A power transmission system is the most important issue for the design of high performance tractors. Many operations, such as loading and lifting, use hydraulic power. In the present study, a hydraulic power transmission system for the 3-point hitch of a 50 kW narrow tractor was developed and its performance was evaluated. First, major components were designed based on target design parameters. Target operations were spraying, weeding, and transportation. Main design parameters were determined through mathematical calculation and computer simulation. The capacity of the hydraulic cylinder was calculated taking the lifting force required for the weight of the implements into consideration. Then, a prototype was fabricated. Major components were the lifting valve, hydraulic cylinder, and 3-point hitch. Finally, performance was evaluated through laboratory tests. Tests were conducted using load weights, lift arm sensor, and lift arm height from the ground. Test results showed that the lifting force was in the range of 23.5 - 29.4 kN. This force was greater than lifting forces of competing foreign tractors by 3.9 - 4.9 kN. These results satisfied the design target value of 20.6 kN, determined by survey of advanced foreign products. The prototype will be commercialized after revision based on various field tests. Improvement of reliability should be also achieved.

• 한국초등과학교육학회지:초등과학교육
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• 제33권3호
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• pp.439-452
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• 2014

The purpose of this study is to find out the effect of STEAM program on the scientific communication skills and the learning flow of elementary gifted students. The main findings of this study are as follows: First, STEAM program that mathematical, technical, engineering and art factors were combined based on basic concepts of science were developed. Seconds, the change in the scientific communication skills of experimental group applying STEAM program had statistically meaningful difference (p<.05). Third, the flow of experimental class improved, but it had no meaningful difference statistically (p>.05). But it is expected that continuing level adjusted STEAM program might have positive effect on improving the flow with the following three reasons: 1) The gifted students' flow level on learning before experiment was rather too high to expect short term effect. 2) It was hard for them to achieve flow experience because topic difficulties and students' capacities were not balanced. 3) topic commitments and autotelic behaviors of gifted students were observed during classes. Fourth, by the result of the student satisfaction questionnaire survey on this program, students actively participated in the STEAM program with interest and curiosity. As achieved self-directed problem solving, versatile communication activities and success experiences, their class satisfaction was high. Based on such results, it was expected that the gifted class applied of STEAM program could enhance scientific communication capacity of the elementary gifted students and would further positively influence flow of learning as well. In addition, it was considered to have integrated approach value to elementary gifted and talented education in the aspect that it could satisfy various educational demands of gifted students.

• 대한수학교육학회지:학교수학
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• 제18권1호
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• pp.143-157
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• 2016

본 연구에서는 개정 전후 교과서인 2009년과 2013년 북한 초급중학교 1학년 수학교과서를 대상으로 하여 내용 조직, 내용 전개, 내용 구성 방식 등의 변화방향을 분석하였다. 연구결과는 다음과 같다. 첫째, 내용 조직과 관련하여 대단원이 1단원 감소하였지만 중단원의 수는 그대로이며 소단원의 수는 4단원 증가하였다. 둘째, 내용 전개에 상당한 변화가 나타났다. 학생의 참여를 독려하고 학생에게 친근한 형태의 전개를 추구하는 경향이 확인되었다. 셋째, 내용 영역 구성과 관련하여, 분명한 변화가 나타났다. 수와 연산, 문자와 식 영역의 비율이 절반 가까이 줄어드는 대신 규칙성, 기하, 함수, 확률과 통계, 도형의 방정식, 집합과 명제 영역에 새로운 내용이 추가되었다. 이상과 같이 초급중학교 1학년 수학교과서의 내용 조직, 내용 전개, 내용 구성에 나타난 변화는 남한의 수학교과서와 비교할 때 여전히 큰 차이를 보이지만 과거에 비해 간격이 좁혀지고 있음을 시사한다. 결론적으로 2012년에 이루어진 북한의 수학교육과정 개정과 그에 따른 수학교과서는 남한에서 추구하는 수학교육의 기본 방향과 부합되는 측면이 증가되는 방향으로 변화하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.400-410
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• 2010

In an identity-based threshold broadcast encryption (IDTHBE) scheme, a broadcaster chooses a set of n recipients and a threshold value t, and the plaintext can be recovered only if at least t receivers cooperate. IDTHBE scheme is different from the standard threshold public key encryption schemes, where the set of receivers and the threshold value are decided from the beginning. This kind of scheme has wide applications in ad hoc networks. Previously proposed IDTHBE schemes have ciphertexts which contain at least n elements. In addition, the security of theses schemes relies on the random oracles. In this paper, we introduce two new constructions of IDTHBE for ad hoc networks. Our first scheme achieves S-size private keys while the modified scheme achieves constant size private keys. Both schemes achieve approximately (n-t)-size ciphertexts. Furthermore, we also show that they are provablesecurity under the decision bilinear Diffie-Hellman Exponent (BDHE) assumption in the standard model.

• 감성과학
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• 제5권1호
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• pp.17-24
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• 2002

본 연구는 객관적인 생리신호로부터 인간의 감성을 추론할 수 있는 감성평가 전문가 시스템을 개발하기 위한 첫 번째 단계로 측정된 생리신호를 이용하여 인간의 긴장도를 판단하는 알고리즘의 개발을 목표로 한다. 감성평가와 관련된 애매함을 수리적으로 취급하기 위해 퍼지이론을 적용하여 임의의 감성영역에 속하는 정도를 소속함수로 정량화함으로써 감성평가를 가능하게 하고자 하였다. 소속함수의 결정은 상상을 통해 유발된 긴장/이완의 생리신호 데이터베이스 결과를 사용하였다. 그리고 두 가지 이상의 생리신호 측정결과와 각 생리신호의 소속함수로부터 하나의 최종결과(긴장도)를 유추하기 위해서 Dempster-Shafer증거합 법칙을 적용하였고, 이를 통해 최종적인 긴장도를 도출할 수 있도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4153-4169
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• 2014

To recognize F5-like (such as F5 and nsF5) steganographic algorithm from multi-class stego images, a recognition algorithm based on the identifiable statistical feature (IDSF) of F5-like steganography is proposed in this paper. First, this paper analyzes the special modification ways of F5-like steganography to image data, as well as the special changes of statistical properties of image data caused by the modifications. And then, by constructing appropriate feature extraction sources, the IDSF of F5-like steganography distinguished from others is extracted. Lastly, based on the extracted IDSFs and combined with the training of SVM (Support Vector Machine) classifier, a recognition algorithm is presented to recognize F5-like stego images from images set consisting of a large number of multi-class stego images. A series of experimental results based on the detection of five types of typical JPEG steganography (namely F5, nsF5, JSteg, Steghide and Outguess) indicate that, the proposed algorithm can distinguish F5-like stego images reliably from multi-class stego images generated by the steganography mentioned above. Furthermore, even if the types of some detected stego images are unknown, the proposed algorithm can still recognize F5-like stego images correctly with high accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3554-3570
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• 2021

With the rapid development of the Chinese water project, the safety monitoring of dams is urgently needed. Many drawbacks exist in dams, such as high monitoring costs, a limited equipment service life, long-term monitoring difficulties. MEMS sensors have the advantages of low cost, high precision, easy installation, and simplicity, so they have broad application prospects in engineering measurements. This paper designs intelligent monitoring based on the collaborative measurement of dual MEMS sensors. The system first determines the endpoint coordinates of the sensor array by the coordinate transformation relationship in the monitoring system and then obtains the dam settlement according to the endpoint coordinates. Next, this paper proposes a dual-MEMS sensor collaborative measurement algorithm that builds a mathematical model of the dual-sensor measurement. The monitoring system realizes mutual compensation between sensor measurement data by calculating the motion constraint matrix between the two sensors. Compared with the single-sensor measurement, the dual-sensor measurement algorithm is more accurate and can improve the reliability of long-term monitoring data. Finally, the experimental results show that the dam subsidence monitoring system proposed in this paper fully meets the engineering monitoring accuracy needs, and the dual-sensor collaborative measurement system is more stable than the single-sensor monitoring system.