• 한국산학기술학회논문지
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• 제20권2호
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• pp.492-497
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• 2019

본 연구에서는 빅데이터 시대에 주목을 받고 있는 온라인 맞춤형 광고를 활성화시킬 목적으로 기존 연구들에서 분명하게 규명되지 않았던 '개인 정보'와 '행태정보'의 의미를 명확히 하기 위해 '개인 정보'에 대한 법적 개념을 분석하였다. 분석 대상으로는 '개인정보보호법' 및 동법 시행령에 근거하여 마련된 '개인 정보 침해 요인 평가 지침'과 '개인 정보 비식별 조치 가이드라인'을 선정하였다. 결과에 의하면, '개인 정보'란, (1)살아 있는 개인(단체, 법인, 사물 등은 해당되지 않음)에 관한 모든 종류의 정보로서, (2)개인을 알아볼 수 있는 정보(식별자)이며 개인을 알아보기 어려운 것은 해당되지 않으며, (3)해당 정보 자체로는 개인을 알아볼 수 없어도 다른 정보와 쉽게 결합(결합 대상 정보의 입수 가능성, 결합 가능성이 있어야 함)하여 알아볼 수 있는 정보(속성자)를 포함한다. 보다 구체적으로, 개인 정보에는 기본정보, 고유식별정보, 민감정보, 기타 개인정보 등이 포함된다. 그리고 향후의 연구 방향으로서 기술 발달에 따른 '개인 정보' 개념에 대한 지속적인 연구, '온라인 맞춤형 광고 개인 정보 보호 가이드라인'의 실효성에 대한 연구, 이용자는 물론 사업자의 시각에서 본 개인 정보 보호의 법리에 대한 연구 및 개인 정보와 행태 정보의 명확한 구분을 전제로 한 온라인 맞춤형 광고 연구의 필요성 등을 제안하였다.

• 대한수학회보
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• 제21권2호
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• pp.67-75
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• 1984

Let X be a topological space. We consider a groupoid G over X and the quotient groupoid G/N for any normal subgroupoid N of G. The concept of groupoid (topological groupoid) is a natural generalization of the group(topological group). An useful example of a groupoid over X is the foundamental groupoid .pi.X whose object group at x.mem.X is the fundamental group .pi.(X, x). It is known [5] that if X is locally simply connected, then the topology of X determines a topology on .pi.X so that is becomes a topological groupoid over X, and a covering space of the product space X*X. In this paper the concept of the locally simple connectivity of a topological space X is applied to the groupoid G over X. That concept is defined as a term '1-connected local subgroupoid' of G. Using this concept we topologize the groupoid G so that it becomes a topological groupoid over X. With this topology the connected groupoid G is a covering space of the product space X*X. Further-more, if ob(.overbar.G)=.overbar.X is a covering space of X, then the groupoid .overbar.G is also a covering space of the groupoid G. Since the fundamental groupoid .pi.X of X satisfying a certain condition has an 1-connected local subgroupoid, .pi.X can always be topologized. In this case the topology on .pi.X is the same as that of [5]. In section 4 the results on the groupoid G are generalized to the quotient groupoid G/N. For any topological groupoid G over X and normal subgroupoid N of G, the abstract quotient groupoid G/N can be given the identification topology, but with this topology G/N need not be a topological groupoid over X [4]. However the induced topology (H) on G makes G/N (with the identification topology) a topological groupoid over X. A final section is related to the covering morphism. Let G$_{1}$ and G$_{2}$ be groupoids over the sets X$_{1}$ and X$_{2}$, respectively, and .phi.:G$_{1}$.rarw.G$_{2}$ be a covering spimorphism. If X$_{2}$ is a topological space and G$_{2}$ has an 1-connected local subgroupoid, then we can topologize X$_{1}$ so that ob(.phi.):X$_{1}$.rarw.X$_{2}$ is a covering map and .phi.: G$_{1}$.rarw.G$_{2}$ is a topological covering morphism.

• 대한수학회보
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• 제54권6호
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• pp.2107-2117
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• 2017

We study the quasi-commutativity in relation with powers of coefficients of polynomials. In the procedure we introduce the concept of ${\pi}$-quasi-commutative ring as a generalization of quasi-commutative rings. We show first that every ${\pi}$-quasi-commutative ring is Abelian and that a locally finite Abelian ring is ${\pi}$-quasi-commutative. The role of these facts are essential to our study in this note. The structures of various sorts of ${\pi}$-quasi-commutative rings are investigated to answer the questions raised naturally in the process, in relation to the structure of Jacobson and nil radicals.

• 대한수학교육학회지:학교수학
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• 제18권3호
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• pp.647-666
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• 2016

본 연구는 수학적 표현이 개념적 이해를 형성하는 수단이라는 관점을 토대로 예비교사들의 무리수 개념과 표현 방식에 대한 이해 정도를 조사하여 무리수 개념 지도를 위한 교수학적 시사점을 도출하고자 하였다. 이에 무리수 개념과 표현, 다양한 표현, 표현간 번역 항목을 조사하는 검사도구를 예비교사 48명을 대상으로 적용하였다. 체계적인 분석을 위해 무리수 표현을 비(非)분수, 소수, 기호, 기하, 수직선, 함숫값 표현으로 범주화하여 활용하였다. 분석 결과, 예비교사들은 무리수 정의의 비(非)분수 표현에 내포된 통약불가능성을 명확하게 인식하지 못하였으며, 무리수의 다양한 표현 중에서 기호 표현에 집중 경향을 나타냈고, 다른 표현들을 상대적으로 간과하는 현상을 나타내었다. 특히 규칙성이 있는 비순환 무한소수에 대한 제한된 이해와 무한소수에 대한 일관성 있는 이해의 결여를 확인할 수 있었다. 또한 기호 표현 $\sqrt{5}$에 비해 ${\pi}$를 다른 표현으로 번역하는데 더 큰 어려움을 나타냈으며, ${\pi}$를 번역하는 과정에서 가무한의 관점이 드러나기도 하였다. 이상의 연구결과를 종합하여 무리수 개념 지도는 무리수 정의와 표현의 관계, 다양한 무리수 표현의 이해, 무리수 표현간의 번역에 중점을 두어 지도되어야 함을 주장하였다.

• 대한수학교육학회지:수학교육학연구
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• 제27권4호
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• pp.811-831
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• 2017

본 연구의 목적은 원주율과 관련되는 조선산학의 내용을 교수학적 차원에서 분석하는 것이며, 분석 내용을 바탕으로 원주율에 대한 심화된 이해를 돕는 교수 학습활동을 조직화하는 것이다. 이를 위해 먼저 조선산학서 <묵사집산법>, <구수략>, <구일집>에 대한 상세 분석을 수행하였다. 분석 결과, 조선에서 사용한 고법, 휘율, 밀률을 비롯한 다양한 원주율의 근삿값이 지름과 원주의 비라는 원주율의 의미가 잘 드러나는 형태로 제시되었다는 것과 문제의 상황에 맞게 원주율을 적절히 선택하게 함으로써 계산의 정확도를 조정할 수 있었다는 것을 확인하였다. 이상의 분석 결과를 종합하여, 원주율에 대한 심화학습 자료로 활용 가능한 구체적인 교수 학습활동으로 조직화하였다. 교수 학습활동은 원주율의 뜻과 원주율의 근삿값 설명하기, 원주 또는 원의 넓이 계산 방법에 대해서 교과서 방법과 비교 설명하기, 원의 넓이와 정사각형의 넓이의 비의 관계 설명하기 등 총 4가지 활동으로 구성하여 제시하였다.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제18권1호
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• pp.1-29
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• 2014

When taught the precise definition of ${\pi}$, students may be simply asked to memorize its approximate value without developing a rigorous understanding of the underlying reason of why it is a constant. Measuring the circumferences and diameters of various circles and calculating their ratios might just represent an attempt to verify that ${\pi}$ has an approximate value of 3.14, and will not necessarily result in an adequate understanding about the constant nor formally proves that it is a constant. In this study, we aim to investigate prospective teachers' conceptual understanding of ${\pi}$, and as a constant and whether they can provide a proof of its constant property. The findings show that prospective teachers lack a holistic understanding of the constant nature of ${\pi}$, and reveal how they teach students about this property in an inappropriate approach through a proving activity. We conclude our findings with a suggestion on how to improve the situation.

• 전기의세계
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• 제30권2호
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• pp.101-111
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• 1981

This paper describes two methods which generate all the prime implicants (PI's) quickly by using the directions of adjacency tavle (DA-table) that gives the knowledge of adjacency relations among the given minterms. One is a graphical method that enables us to generate PI's by hand, the other is a checking method that determines the existance of PI's quickly when it is programmed on a digital computer. And a fast minimization algorithm will be shown in this paper that can be implemented with reduced computational effort by selecting essential prime implicants (EPI's) first of all and using the concept of the integration of the PI identification and selection procedure. The procedure, proposed in this paper, has all the advantage of Karnaugh mapping, so the procedure is simple and easy.

• 설비공학논문집
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• 제13권4호
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• pp.233-241
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• 2001

In the present study, various experiments were performed to investigate the capacity modulation and transient response control using a variable speed compressor and electronic expansion valve(EEV). Based on the experimental results, the operation control algorithm and real time digital control system were constructed to adjust the superheat at the inlet of the compressor. Superheat control was fulfilled using both the PI feedback controller and PI controller combined with a feedforward concept. As a result, the tracking performance of the latter was better than that of former.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2000년도 추계학술대회 논문집
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• pp.98-104
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• 2000

The conventional model did not take momentum conservation into consideration when the electron absorbs and emits the photons. II-ray provides momentum conservations on any directions of the entering photons, and also the electrons have radial momentum conservations and fully elastic bouncing between two atoms, in the new atom model. Conventional atom model must be criticized on the following four points. (1) Natural motions between positive and negative entities are not circular motions but linear going and returning ones, for examples sexual motion, tidal motion, day and night etc. Because the radius of hydrogen atom's electron orbit is the order of 10$^{-11}$ m and the radia of the nucleons in the nucleus are the order of 10$^{-14}$ m and then the converging $\pi$-gamma rays to the nucleus have so great circular momentum, the electron can not have a circular motion. We can say without doubt that any elementary mass particle can have only linear motion, because of the $\pi$-rays'hindrances, nearthenucleus. (2) Potential energy generation was neglected when electron changes its orbit from outer one to inner one. The h v is the kinetic energy of the photo-electron. The total energy difference between orbits comprises kinetic and potential energies. (3) The structure of the space must be taken into consideration because the properties of the electron do not change during the transition from outer orbit to inner one even though it produces photon. (4) Total energy conservation law applies to the energy flow between mind and matter because we daily experiences a interconnection between mind and body. Conventional Concept of Electric Field must be extended in the case of the direct and alternating current. Conventional concept is based on coulomb's force while the electric potential in the direct and alternating current is from Gibb's free energy. And also conventional concept has not any consciousness with human being but the latters has a conscious sensibility. The cell emf is from the kinetic energy of the open $\pi$-rays flow through the conducting wire. The electric potential in alternating current is from that the trans-orbital moving of the induced change of magnetic field in the wire produces flows of open $\pi$-rays, which push the rotating electrons on the orbital and then make the current flow. Human consciousness can induce a resonance with the sensibility of the open $\pi$-rays in the electric measuring equipment. Specially treated acupunctures with Nasucon is for sending an acupunctural effect from one place to another via space by someone's will power.

• Journal of Power Electronics
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• 제18권3호
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• pp.766-777
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• 2018

In this paper, a sliding mode and proportional plus integral (SM-PI) control combined with self-sustained phase shift modulation (SSPSM) for LLC resonant converters is presented. The proposed control scheme improves the transient response while preserving good steady-state performance. An averaged large signal model of an LLC converter with the ZVS modulation technique is developed for the SM control design. The sliding surface is obtained based on the input-output linearization concept. A system identification method is adopted to obtain the transform function of the LLC resonant converter, which is used to design the PI control. In order to reduce the inherent chattering problem in the steady state, the combined SM-PI control strategy is derived with fuzzy control, where the SM control is responsive during the transient state while the PI control prevails in the steady state. The combination of SSPSM and the SM-PI control provides ZVS operation, robustness and a fast transient response against step load variations. Simulation and experimental results validate the theoretical analysis and the attractive features of the proposed scheme.