• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.16 no.2
• /
• pp.171-179
• /
• 2017

In this paper, microstrip antenna using multi-layer and folded structure for GPS application is presented for aircraft loading. Existing microstrip patch antenna used dielectric of high specific inductive capacity to miniaturize that cause smaller bandwidth and decline of efficiency due to dielectric loss. To compensate the existing flaws, Rogers TMM 10i(dielectric constant=9.8, loss tangent=0.002) is used for multi-layer dielectric miniaturization, and we construct folded radiating element on the surface of the dielectric applying perturbation effect. The antenna is designed in the bandwidth of GPS $L_1$ band, and the size of the antenna's radiating element is $20.3mm{\times}19.93mm$, and it gets 94.2% miniaturized characteristic of basic ${\lambda}/2$ microstrip patch antenna. Also the measured -10 dB bandwidth is 32.3 MHz(2.05%), 3 dB axial ratio bandwidth is 6.7 MHz(0.43%). Measured radiation patterns was maximum gain of 0.56 dBi at x axis polarization, 1.23 dBi at y axis polarization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.1
• /
• pp.80-83
• /
• 2017

In this paper, the X-band reconfigurable frequency selective surface having flexible geometry was proposed. The proposed RFSS is composed of patterns of cross-shaped loop with inductive stub, which can control the frequency response for C-Band and X-band by ON/OFF state of PIN diode. To minimize the parasitic effect and to obtain the high level of isolation between the unit cell of FSS and the bias circuit, we designed the grid type bias line on bottom layer through via hole. The measured transmission characteristics show good agreement with the simulation results and good stability of frequency response for different incident angles and curvatures of surface.

• Journal of Korean Elementary Science Education
• /
• v.25 no.3
• /
• pp.307-317
• /
• 2006

Those students with ability and interest in science should be supported to develop their potential and to reach high levels of achievement in science and technology. In order to ensure that gifted pupils are able to enhance their creativity as well as research abilities, appropriate learning programs and environments are essential. One of the various teaching and learning models for the gifted in science is the discovery learning model based on inductive science activities. There is a clear line of continuity between knowledge discovery at the forefront of research and student's learning activities. If students receive excellent training in organizing scientific concepts for themselves, they will be able to skillfully apply appropriate scientific concepts and solve problems when facing unfamiliar situations. It is very important to offer an appropriate learning environment to maximize the learning effect whilst, at the same time, understanding individual student's characteristics. In this study, the authors took great pains to research effective learning environments for gifted science students. Firstly, appropriate classroom learning environments thought by the teacher to offer the most potential were investigated. 3 different classes in which a revised teaching and learning environment was applied in sequence were examined. Inquiries were conducted into students' activities and achievement through observation, interviews, and examination of students' worksheets. A Science Education expert and 5 elementary school teachers specializing in gifted education also observed the class to examine the specific character of gifted science students. A number of suggestions in discovery learning classes for elementary students gifted in science are possible; 1) Readiness is essential in attitudes related to the inquiry. 2) The interaction between students should be developed. A permissive atmosphere is needed in small group activities. 3) Students require training in listening to others. In a whole class discussion, a permissive atmosphere needs to be restricted somewhat in order to promote full and inclusive discussion. 4) Students should have a chance to practice induction and abduction methods in solving problems.

• BMB Reports
• /
• v.32 no.1
• /
• pp.51-59
• /
• 1999

The Korean radish cationic peroxidase (KRCP) promoter, comprising nucleotides -471 to +704 relative to the transcriptional initiation site, was fused to the GUS gene and transformed to tobacco BY-2 cells. We examined how auxin (2,4-dichlorophenoxyacetic acid, 2,4-D), cytokinin (6-benzylaminopurine, BAP), gibberellic acid ($GA_3$), abscisic acid (ABA), methyl jasmonate (MeJA), and phosphatidic acid (PA) affect the GUS expression in the presence or absence of 2,4-D in a modified LS medium. Exogenous 2,4-D or BAP greatly decreased the GUS expression regulated by the KRCP promoter in a modified LS medium containing 0.2 mg/l 2,4-D. $GA_3$ increased the GUS expression and ABA completely reduced the inductive effect of $GA_3$. The GUS expression was also increased dose-dependently by plant defense regulators, MeJA and PA. In contrast to the above results, auxin deprivation from the modified LS medium increased the GUS expression after treatment with exogenous 2,4-D whereas BAP still greatly decreased the GUS expression dose-dependently. $GA_3$ or MeJA slightly decreased the GUS expression. The data suggest that auxin deprivation changes the sensitivity of the suspension cells to exogenous chemicals and that the regulation of the KRCP promoter by 2,4-D, $GA_3$, and MeJA is dependent on auxin, whereas the regulation by BAP is not. This study will be valuable for understanding the function and expression mode of the Korean radish cationic peroxidase in Korean radish.

• Journal of the Korean School Mathematics Society
• /
• v.10 no.1
• /
• pp.91-111
• /
• 2007

This study investigated how high school students predict the rule, the sum of sequence for the concept of sequence, for the given patterns based on inductive approach using computers that provide dynamic functions and materials that are visual. Students for themselves were able to induce the formula without using the given formula in the textbook. Furthermore, this study examined how these technology and materials affect students' understanding of the concept of actual infinity for those who have the concept of the potential infinity which is the misconception of infinity in a infinity series. This study shows that students made a progress from the concept of potential infinity to that of actual infinity with technology and materials used I this study. Students also became interested in the use of computer and the visualized materials, further there was a change in their attitude toward mathematics.

• Journal of the Korean Society for Railway
• /
• v.13 no.5
• /
• pp.504-508
• /
• 2010

The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO (Gate Turnoff Thyristor) technology. The IGBT combines the advantages of a power MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) and a bipolar power transistor. The change of electrical characteristics for IGBT is mainly coming from the change of characteristics of MOSFET at the input gate and the PNP transistors at the output. The change of threshold voltage, which is one of the important design parameters, is brought by charge trapping at the gate oxide under the environment that radiation exists. The energy loss will be also studied as the inductance values are changed. In this paper, the electrical characteristics are simulated by SPICE, and compared for variation of inductance and threshold voltage based on IGBT.

• Korean Journal of Plant Tissue Culture
• /
• v.26 no.3
• /
• pp.211-217
• /
• 1999

The effect of auxins and cytokinins on the formation of adventitious shoots, adventitious roots, trichomes, and calli in MS basal medium was investigated in leaf segments from ecotype Columbia of Arabidopsis thaliana. Adventitious shoots, adventitious roots, trichome, and calli were formed from leaf segments by a wide range of hormone concentrations and combinations. Adventitious shoots were formed respectively in treatment with 0.1mg/L IAA and 10 mg/L BA. Adventitious roots were formed in treatments with low concentration of IAA and NAA. Trichomes and calli were formed by increasing the concentration of IAA and NAA. The optimal combination was 0.5mg/L NAA and 0.1mg/L BA for trichome formation, 10mg/L NAA and 10mg/L BA for calli formation. When NAA was treated alone in culture media, adventitious roots were formed in 0.1mg/L, trichomes were formed in 2.0mg/L, and calli were formed in 10mg/L. Inductive time for formation of adventitious roots, trichomes and calli were determined at 6,7 and 18 days respectively by periodical transfer of leaf segments from NAA containing medium to NAA free medium.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.11a
• /
• pp.171-171
• /
• 2012

In this study, we fabricated the high-brightness AlGaInP-based red light emitting diodes (LED)s using by direct printing technique and inductive coupled plasma (ICP) reactive ion etching (RIE). In general, surface roughening was fabricated by wet etching process to improve the light extraction efficiency of AlGaInP-based red LED. However, a structure of the surface roughening, which was fabricated by wet etching, was tiled cone-shape after wet etching process due to crystal structure of AlGaInP materials, which was used as top-layer of red LED. This tilted cone-shape of surface roughening can improve the light extraction of LED, but it caused a loss of the light extraction efficiency of LED. So, in this study, we fabricated perfectly cone shaped pattern using direct printing and dry etching process to maximize the light extraction efficiency of LED. Both submicron pattern and micron pattern was formed on the surface of red LED to compare the enhancement effect of light extraction efficiency of LEDs according to the diameter of sapphire patterns.After patterning process using direct printing and ICP-RIE proceeded on the red LED, light output was enhanced up to 10 % than that of red LED with wet etched structure. This enhancement of light extraction of red LED was maintained after packaging process. And as a result of analyze of current-voltage characteristic, there is no electrical degradation of LED.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.5
• /
• pp.452-461
• /
• 1997

In this paper, we present a computer-aided design(CAD) technique for minimizing the phase shift in microstrip PIN diode attenuators due to the junction capacitance in the equivalent circuit model of PIN diode. Microstrip PIN diode attenuators use the characteristics which the reactance of microstrip line changes from inductive to capacitive as the frequency sweeps across the band. Microstrip PIN diode attenuator designed utilizes the quarter-wavelength transmission line terminating with the half-moon radial stub, which is designed for negligible phase shifting effect over the intersted bandwidth. The attenuator has similar phase shift at 0 dB and 10 dB of attenuation within average $1.27^{\circ}$ between 1.2GHz and 1.9GHz. The input and output return losses between 1.4 GHz and 1.9 GHz are less than 10 dB over the attenuation range of 0 dB and 10 dB.

• Lingua Humanitatis
• /
• v.1 no.1
• /
• pp.13-31
• /
• 2001

This essay seeks new possibilities in experimental thinking and to find ways in which philosophy can aid humanistic imagination. In emphasizing logical precision, philosophy has so far ignored the role of imagination in philosophical logic and limited itself to deductive logic. Despite the obvious fact that no degree of logical precision can fully account for, nor provide complete expression for, the vast range of human thought, other modes of thinking have suffered in the shadow of deductive logic. But these non-deductive models of thinking can in many cases better explain the emotive, aesthetic logic of the humanities. The kinds of models (deductive and non-deductive) in humanistic thinking include dialectic, abductive, analogic, pragmatic, inductive, and deductive logic. Each mode of logical thinking may be assigned a color that represents its emotive characteristics: red for dialectics (opposition): blue for abduction (transcendence); yellow for analogy (flexibility); green for pragmatics (peace); violet/purple for induction (fantasy); and finally orange for deduction (trust). And each mode can also be keyed to major areas in humanistic thought, making up the following connections: dialectic-red-history; abduction-blue-literature; analogy-yellow-philosophy ; pragmatics-green-religion ; induction-violet/purple-arts; and deduction-orange-science. These connections serve to illustrate the interrelationship between emotion and intelligence, leading us toward considerations of emotional intelligence and intelligent emotion. The former is increasingly gaining attention, as the effect of 'mood space' on intelligence is being scrutinized. That the rate of suicide among mathematicians is very high points to the need for careful study of the reverse relationship between emotion and intelligence, intelligent emotion. The need for the latter is all the more pressing, as the emergence of new technology is allowing, even forcing, us more and more to experience the world intellectually (i.e., sans emotive experience) through a new virtual space called cyberspace.