• Journal of the Korean School Mathematics Society
• /
• v.2 no.1
• /
• pp.219-229
• /
• 1999

Nowadays the use of computer has a tendency to be being increased in classroom. Also, Many mathematics teachers are attempting to use computer efficiently in classroom. Computer has unique functions such as graphic, animation, and error correction. As graphic and animation can make the content of mathematics visible and make it easy for learners to study mathematics, it is desirable to develop the computer educational program and use it in teaching and learning mathematics. Especially, before concepts study on the unit of Figure or Function, the use of graphic or animation is efficient by being able to understand easily the content. The purpose of this thesis is to produce the computer program on the Movement of Figure in the unit of Equation of Figure which is in mathematics curriculum for the first grade of high school. In teaching and learning mathematics by use of this program, the educational effects are expected as follows: 1. It is expected that this program will stimulate the interest of learners by using animation and acoustic (sound) effect and so learners' voluntary and active thinking activity will be shown. 2. It will be helpful to form exact concept because it is possible to understand intuitively the basic concepts on the Movement of Figure by using graphic and animation. 3. It is expected that the repeated study of this program already designed will remove the fear of incomplete parts and help review them. 4. It is possible to change from teacher-centered instruction, which is the blind point of recent mathematics education, to the learner-centered instruction. However, it is necessary to realize that using the educational engineering (computer) in mathematics education cannot always cause learners to study mathematics very well and that computer cannot take the place of mathematics teacher. Accordingly, computer will be treated as aids which help learners study difficult part.

• School Mathematics
• /
• v.10 no.3
• /
• pp.443-461
• /
• 2008

The purpose of this study was to provide teachers with suggestions on how to teach the unit of finding the area of plane figure by analyzing students' different solution methods. The solution methods were analyzed according to how the original area of the given figure was kept: partition, transformation, and elimination. The partition method was most used. With regard to transformation, students seemed to find it easy to use the area of rectangle. With regard to elimination, students were successful using elimination to find the area of a given figure but had difficulty in producing a formula from the method. The teacher played a key role to encourage students to employ different solution methods, and gave them opportunities to compare and contrast various methods. A cautionary note is that, with too much emphasis on 'variety', the mathematical efficiency may be lost in the process. It suggests that a teacher should be careful to establish appropriate sociomathe- matical norms with students in order that they can make their own judgment on which solution method is mathematically worth and efficient.

• Korean Chemical Engineering Research
• /
• v.53 no.2
• /
• pp.174-180
• /
• 2015

The flow pattern and the solid-liquid mass transfer coefficient in figure-eight shaking vessels were observed by experimental method. The flow patterns, mixing time, power consumption and mass transfer coefficient in the figureeight shaking vessels changed irregularly with increase in the shaking frequency. Any frequency, even in the Fr = 0.095 or more became clear experimentally. The region of the optimum operating condition of the figure-eight shaking was larger than that of the reciprocal shaking. The solid-liquid mass transfer coefficient was correlated with the same correlation as that of the rotary shaking vessel of existing. The gas-liquid mass transfer coefficient of the figure-eight shaking vessel was also correlated with the same type of correlation as that of the rotary shaking vessel of existing.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1783-1785
• /
• 1999

In this paper, we apply V-Q Lissajoucs' figure for observation of a V-Q (Voltage-Charge) hysteresis loop at interface between phosphor and insulation layer in P-ELDz which are a simple structure and the back lighting of LCDs (Liquid Crystal Display). In V-Q Lissajous' figure, we measured a change of hysteresis loop according to the thickness of Insulation and phosphor layer. From experiment result, we will be obtained a optimum thickness of insulation with comparing the correlation of a V-L (Voltage-Luminance) and V-Q hysteresis loop.

• Journal of electromagnetic engineering and science
• /
• v.16 no.4
• /
• pp.241-247
• /
• 2016

This paper proposes the design and measurement of a 6-18 GHz front-end receiver module that has been combined into a one- channel output from a two-channel input for electronic warfare support measures (ESM) applications. This module includes a limiter, high-pass filter (HPF), power combiner, equalizer and amplifier. This paper focuses on the design aspects of reducing the noise figure (NF) and matching the phase and amplitude. The NF, linear equalizer, power divider, and HPF were considered in the design. A broadband receiver based on a combined configuration used to obtain low NF. We verify that our receiver module improves the noise figure by as much as 0.78 dB over measured data with a maximum of 5.54 dB over a 6-18 GHz bandwidth; the difference value of phase matching is within $7^{\circ}$ between ports.

• Korean Journal of Optics and Photonics
• /
• v.13 no.2
• /
• pp.89-91
• /
• 2002

A test method that can measure the parallelism and the surface figure of an nontransparent plate using visible light is proposed. The testing system consists of a Twyman-Green interferometer. In addition, test results for the IR filter of IR MTF measuring system are described.

• Journal of the Korean Magnetics Society
• /
• v.4 no.3
• /
• pp.249-255
• /
• 1994

Magneto-optical disks with dielectric layers for optical tunning are useful for maximizing the SNR. We have developed a computer program based on characteristic matrix to investigate the best combination of the film thicknesses. We have optimized the thicknesses of the multilayers which were composed of TbFeCo, dielectric, and AI layers at the wavelengh of 830nm. The criterion for the optimization of the film thickness was to maximize the figure of merit with maintaining the low ellipticity and rmre than 10% reflectivity.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.311-315
• /
• 2001

This paper presents the result of basic study about corrective polishing for arbitrary surface figure. In this study, we researched polishing characteristics on the working condition of optical glass. The abrasive size, relative velocity and working pressure were selected major factors that affect polishing process. The Preston's equation which is the representative model of polishing process was used to model the unit removal shape. The Preston's coefficient and unit removal function were calculated from the polished surface. Applying these results, we have shown that the systematic corrective polishing of arbitary figure is feasible through experiments and analysis.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2000.11a
• /
• pp.216-219
• /
• 2000

A Ka Band 3-stage MMIC (Monolithic Microwave Integrated Circuits) LNA(Low Noise Amplifiers) has been designed. The MMIC LNA consists of two single-ended type amplication stapes and one balanced type amplication stage to satisfy noise figure characteristics and high gain and amplitude linearity. The 0.15um pHEMT has been used to provide a ultra low noise figure and high gain amplification. Series and Shunt feedback circuits were inserted to ensure high stability over frequency range of DC to 80 GHz. The size of designed MMIC LNA is 3100mm ${\times}$ 2400um(7.44$\textrm{mm}^2$). The on wafer measured noise figure of the MMIC LNA is less than 2.0 dB over frequency range of 22 GHz to 30 GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2002.11a
• /
• pp.209-212
• /
• 2002

본 논문에서는 위성방송 수신용 광대역 저잡음 증폭기를 설계 및 구현하였다. 전산모의 실험용 소프트웨어를 사용하여 저잡음 증폭기를 설계하였고, 제작된 저잡음 증폭기의 전기적 특성을 네트워크 분석기와 Noise Figure 분석기를 사용하여 측정하였다. LNA단의 Noise Figure에 중점을 두고 샘플을 제작하여 측정한 길과 전산모의실험에서 나온 데이터는 0.46㏈이하였고 전체 시스템에서 측정된 Noise figure는 0.6㏈정도의 좋은 길과를 나타내었지만, 반면에 이득과 반사손실의 결과가 약간 떨어짐을 보였다 위성 인터넷 등 위성을 이용하는 통신 인구의 급격한 증가와 더불어 구현된 저잡음 증폭기를 사용한 LNB(Low Noise Block down converter)가 널리 응용될 것으로 기대된다.