• Title/Summary/Keyword: arbitrary reflection

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Wave propagation in an Inhomogeneous Anisotropic Medium through Variational Finite Element Method (변분 유한요소법에 의한 비균질 비등방성 매질에서의 전파특성)

  • 김현준;홍용인;김두경;김정기
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.3 no.1
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    • pp.33-41
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    • 1992
  • In this paper the propagation problems of waves nomally incident upon an anisotropic medium with arbitrary permittivity tensors are analyzed through the variational finite element method. First, a variational equation is derived from the new approach basd on the induction theorm, reactions, and reciprocity. Next, by using the finite element method, the propagation problems are solved from the obtained functional. Specially, the reflection and transmission coefficient and axis ratio are obtained on the case of normally incident upon a homogeneous and inhomogeneous anisotropic medium such as cold mgnetoplasma slab and showed agreement with those of the previous method.

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LED simulation analysis using optical system of reflex (반사 광학계를 이용한 LED Simulation 분석)

  • Yoon, Chul-Yong;Noh, Myeong-Jae;Kim, Byoung-Man;Jeong, Byoung-Jo;Roh, Yong-Gi
    • Proceedings of the KAIS Fall Conference
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    • 2010.11a
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    • pp.159-162
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    • 2010
  • There are some limitations to advance technology glaring and luminous Intensity uniformity known as the weak point of existing LED lamp. To improve the two weak points, there have been no special alternative methods so far. Instead, one method which is being used such as the twisting secondary lens or arbitrary structure to remove glaring and improve luminous Intensity uniformity. Based on this academic background, it is necessary to be examined on Technology of Optical System to solve the two weak points by using not complicated but simple methods. This paper will examine the angle of reflection in order to improve luminous intensity uniformity. Also, this research will present the method using lighting analysis program to verify a hypothesis. Through the analysis program, we could understand the simulation analysis method and got some problems about the analysis result. After analysis of causes through reinterpretation of problems, we have reached a conclusion that was changed according to reflectivity and the shape of aspherics by main cause which effected luminous Intensity uniformity and glaring.

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Study on the Promotion Method based on the Scenario of Scientification of Korean Medicine (한의학 과학화의 시나리오에 따른 추진방법 연구)

  • Chi, Gyoo Yong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.33 no.6
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    • pp.334-340
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    • 2019
  • In order to promote scientification of Korean medicine, two hypothetical scenarios were proposed methodologically. Firstly, the scientification of Korean medicine requires a comprehensive understanding of the process and reality, and new logical procedures and the methods of observation and experiment. Secondly, transformation to revised Korean medicine is to replace traditional Korean medicine with biochemistry-based Western medicine, that is a method of reconstructing the recognition foundation describing symptoms and diseases using anatomical platforms and analytical tools. But there are areas of human training and practice that are not subject to scientification, and there are incommensurable parts as for the methodology between western medicine too. And additionally arbitrary rejection by uniform science with a political reason was done. So these various backgrounds and factors should be considered for the scientification of Korean medicine. And before that, reflection and agreement on the understanding and attitude of the method of scientification within the Korean medical community is necessary.

Possibility & Limitation of 1D Nano Scale Electron Shielder (나노 구조물을 이용한 전자선 차폐 가능성과 한계)

  • Ahn, Sung-Jun;Lee, Bum-Su;Kim, Chong-Yeal;Yang, O-Bong;Shin, Hyung-Sik
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11a
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    • pp.301-306
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    • 2005
  • The possibility and limitation of one dimensional nano scale electron shielder is briefly discussed. A Nano scale electron shielder will reduce the weight and size of shielding materials. However, practical application still requires further research. In this work, we discuss general problems related to nano scale electron shielder, by taking an arbitrary one dimensional potential barrier as an example.

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Implementation of a Labview Based Time-Frequency Domain Reflectometry Real Time System for the Load Impedance Measurement (부하 임피던스 측정을 위한 랩뷰기반 시간-주파수 영역 반사파 실시간 시스템 구현)

  • Park, Tae-Geun;Kwak, Ki-Seok;Park, Jin-Bae;Yoon, Tae-Sung
    • Proceedings of the KIEE Conference
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    • 2006.07d
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    • pp.1803-1804
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    • 2006
  • The purpose of this paper is to implement a Labview based TFDR Real Time system through the instruments of Pci eXtensions for Instrumentation(PXI). The proposed load impedance measurement algorithm was verified by experiments via the implemented real time system. The TFDR real time system consisted of the reference signal design, signal generation, signal acquisition, algorithm execution and results display parts. To implement real time system, all of the parts wore programmed by the Labview which is one of graphical programming languages. In the application software implemented by the Labview we were able to design a suitable reference signal according to the length and frequency attenuation characteristics of the target cable and controled the arbitrary waveform generator(ZT500PXI) of the signal generation part and the digital storage oscilloscope(ZT430PXI) of the signal acquisition part. By using the TFDR real time system with the terminal resistor on the target cable, we applied to the load impedance measurements. In the proposed load impedance algorithm a normalized time-frequency cross correlation function and a cross time-frequency distribution function was employed to calculate the reflection coefficient and phase difference between the input and the reflected signals.

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NUMERICAL SIMULATION OF TWO-DIMENSIONAL FREE-SURFACE FLOW AND WAVE TRANSFORMATION OVER CONSTANT-SLOPE BOTTOM TOPOGRAPHY

  • DIMAKOPOULOS AGGELOS S;DIMAS ATHANASSIOS A
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.09b
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    • pp.842-845
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    • 2005
  • A method for the numerical simulation of two-dimensional free-surface flow resulting from the propagation of regular gravity waves over topography with arbitrary bottom shape is presented. The method is based on the numerical solution of the Euler equations subject to the fully nonlinear free-surface boundary conditions and the appropriate bottom, inflow and outflow conditions using a hybrid finite-differences and spectral-method scheme. The formulation includes a boundary-fitted transformation, and is suitable for extension to incorporate large-eddy simulation (LES) and large-wave simulation (LWS) terms for turbulence and breaking wave modeling, respectively. Results are presented for the simulation of the free-surface flow over two different bottom topographies, with constant slope values of 1:10 and 1:20, two different inflow wave lengths and two different inflow wave heights. An absorption outflow zone is utilized and the results indicate minimum wave reflection from the outflow boundary. Over the bottom slope, lengths of waves in the linear regime are modified according to linear theory dispersion, while wave heights remain more or less unchanged. For waves in the nonlinear regime, wave lengths are becoming shorter, while the free surface elevation deviates from its initial sinusoidal shape.

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Model-Based Prediction of Pulsed Eddy Current Testing Signals from Stratified Conductive Structures

  • Zhang, Jian-Hai;Song, Sung-Jin;Kim, Woong-Ji;Kim, Hak-Joon;Chung, Jong-Duk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.6
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    • pp.609-615
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    • 2011
  • Excitation and propagation of electromagnetic field of a cylindrical coil above an arbitrary number of conductive plates for pulsed eddy current testing(PECT) are very complex problems due to their complicated physical properties. In this paper, analytical modeling of PECT is established by Fourier series based on truncated region eigenfunction expansion(TREE) method for a single air-cored coil above stratified conductive structures(SCS) to investigate their integrity. From the presented expression of PECT, the coil impedance due to SCS is calculated based on analytical approach using the generalized reflection coefficient in series form. Then the multilayered structures manufactured by non-ferromagnetic (STS301L) and ferromagnetic materials (SS400) are investigated by the developed PECT model. Good prediction of analytical model of PECT not only contributes to the development of an efficient solver but also can be applied to optimize the conditions of experimental setup in PECT.

The Water Wave Scattering by the Marine Structure of Arbitrary Shape (임의 형태의 해양구조물에 의한 해수파의 산란)

  • 신승호;이중우
    • Journal of the Korean Institute of Navigation
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    • v.17 no.1
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    • pp.61-78
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    • 1993
  • Large offshore structure are to be considered for oil storage facilities , marine terminals, power plants, offshore airports, industrial complexes and recreational facilities. Some of them have already been constructed. Some of the envisioned structures will be of the artificial-island type, in which the bulk of structures may act as significant barriers to normal waves and the prediction of the wave intensity will be of importance for design of structure. The present study deals wave scattering problem combining reflection and diffraction of waves due to the shape of the impermeable rigid upright structure, subject to the excitation of a plane simple harmonic wave coming from infinity. In this study, a finite difference technique for the numerical solution is applied to the boundary integral equation obtained for wave potential. The numerical solution is verified with the analytic solution. The model is applied to various structures, such as the detached breakwater (3L${\times}$0.1L), bird-type breakwater(318L${\times}$0.17L), cylinder-type and crescent -type structure (2.89L${\times}$0.6L, 0.8L${\times}$0.26L).The result are presented in wave height amplification factors and wave height diagram. Also, the amplification factors across the structure or 1 or 2 wavelengths away from the structure are compared with each given case. From the numerical simulation for the various boundary types of structure, we could figure out the transformation pattern of waves and predict the waves and predict the wave intensity in the vicinity of large artificial structures.

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A study of measurement of the unknown load impedance using sectioned transmission line (${\lambda}/4$ 전송선로를 이용한 부하단 임피던스 측정방법에 관한 연구)

  • Hwang, Soo-Sul;Hong, Sung-Yong
    • Journal of Satellite, Information and Communications
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    • v.6 no.2
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    • pp.91-96
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    • 2011
  • In this paper, we present measurement method of the unknown load impedance. Load impedance is continuously varied by external environment conditions. This arbitrarily varied load impedance can be calculated using 3-point voltage measurement on ${\lambda}/4$ sectioned transmission line. We derived several numerical formulas from 3-point voltage measurement results and drew load impedance selection algorithm from calculated load impedance results. These numerical formulas and load impedance selection algorithm are verified by ADS simulation. Simulation results showed that arbitrary load impedance can be correctly measured using above mentioned formulas and selection algorithm.

'Inventing' Religion and Pseudo-religion in the 2022 National Curriculum on Religions (2022년 종교 교육과정 - 종교인 만들기와 '유사종교' 발명 교육 -)

  • Ko Byoung-chul
    • Journal of the Daesoon Academy of Sciences
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    • v.46
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    • pp.1-32
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    • 2023
  • The purpose of this article is to critically reflect on the 2022 national curriculum on religions. The perspective of this reflection is that since the religious curriculum is meant to be a national curriculum, it should be applicable to all high school students, be shareable, and function as a place for meta-reflection regarding the proper use of the category of religion. For this purpose, I reviewed the form and content of the 2022 curriculum on religions in Section 2. The form of the 2022 curriculum on religions looks similar to the previously utilized curriculum. However, the main change is that the subject of religions was arbitrarily placed into the category of 'subjects for choosing a career.' And the 2022 curriculum on religions has two characteristics in terms of content: the orientation of 'making religious people (spiritual formation)' and the reemergence of the concept of 'pseudo-religion.' In Section 3, I delved into the orientation of 'making religious people through religious reflection' among the characteristics of the 2022 curriculum on religions. In this process, I discovered that the concept of 'reflection as a metacognitive technology,' which was the core of the prior curriculum and school education, was transformed into the concept of 'religious reflection,' and the concepts of spirituality and religiosity were also added. In Section 4, I delved into the dichotomy of 'religion and pseudo-religion.' 'Pseudo-religion' is a new focus in the 2022 curriculum on religions. In this process, I revealed that the concept of 'pseudo-religion' is a combination of an outdated administrative term of the Japanese Government-General of Korea during Japan's occupation of Korea, and as such, the term is inherently value-laden and harmful. I also revealed that determining 'pseudo-religion' in school education regenerates the colonial Japanese Government-General's biased attitudes toward Korean religions and forces teachers to 'invent' (detect or personally appraise) modern day pseudo-religions through arbitrary judgements. The 'curriculum to emphasize religious reflection and detect pseudo-religions in order to create religious people' can distort the subject of religion in the national curriculum as into a 'subject for religion (promotion or degradation).' If this distortion continues, the appropriateness of curriculum on religions existing within the national curriculum will eventually become a subject of debate.