• Korean journal of applied entomology
• /
• v.32 no.2
• /
• pp.208-217
• /
• 1993

Feeding behavior fo female brown planthoppers, Nilaparvata lugens Stal, was examined with an electrical recording technique using DC amplifier and through anatomical observation of stylet ovement in the rice plat with electrical recordings. There was six feeding patterns, type P, S, SB, O, X and Ph with the brown planthopper. Type P was a probing pattern during searching the proper feeding site. Type S appeared to be associated with the initial penetration and changing direction through the tissues, and from this type type SB pattern could be distinguished by the regularity of the large potential drops seen, and might be associated with penetration of the phloem sheath and/or salivation in the phloem sheath. The type O pattern shows none of the large voltage drops which were believed to occur when cell walls were being broken down and passes through a relatively thin layer of cells into an air space. The very constant waveform of the type X pattern could be seen during ingestion within the xylem bundle sheath area. The Ph pattern always followed an SB pattern and was associated with a marked negative voltage drop. When this pattern was seen, the brown planthopper might be ingested plant sap from phloem sheath area.

• Korean journal of applied entomology
• /
• v.44 no.3 s.140
• /
• pp.177-187
• /
• 2005

For the comparison of feeding behavior of Nilaparvata lugens among different rice varieties, electrical penetration graph (EPG) technique was used. Ten rice varieties were selected from national-widely recommended rice varieties cultivating in Chungnam province. The correlation between feeding duration and honeydew amount excreted was investigated, and the types of EPG pattern were analyzed among rice varieties. The EPG patterns divided into 6 types according to electrical specific feature, respectively. Type 1 pattern was a searching feeding sites, resting or wandering on a rice plant. Type 2 pattern was appeared when the insect untaken from phloem sieve element. Type 3 pattern was observed when the insect piercing into the rice plant. Type 4 pattern was observed when the insect salivating in rice plant. Type 5 pattern was observed when the insect ingesting from the xylem. Type 6 pattern was observed when the stylet moving in cell. Feeding duration time on Gum-nam was significantly shorter than Dong-jin, Dae-ahn, Dong-ahn, Dae-san. Also, on Gun-nam, it was shown that the brown planthopper did not penetrate the cuticle for a long time. The total number of excreted honeydew droplets by the brown planthopper was the greatest in Dong-jin variety and the least in Gum-nam variety. In proportion to phloem feeding time, the number of honeydew droplets had been increased. According to the results of EPG patterns and honeydew droplets analysis, N. lugens seems to prefer Dong-jin, Dong-ahn, Dae-san, and Dae-ahn to Gum-nam, Da-san, and Nam-chun rice plant variety.

• Journal of electromagnetic engineering and science
• /
• v.18 no.2
• /
• pp.129-135
• /
• 2018

This paper proposes a design of small controlled reception pattern antenna (CRPA) arrays using circular microstrip loops with frequency-insensitive characteristics. The proposed array consists of seven identical upper and lower circular loops that are electromagnetically coupled, which results in a frequency-insensitive behavior. To demonstrate the feasibility of the proposed feeding mechanism, the proposed array is fabricated, and its antenna characteristics are measured in a full-anechoic chamber. The operating principle of the proposed feeding mechanism is then interpreted using an equivalent circuit model, and the effectiveness of the circular loop shape is demonstrated by calculating near electromagnetic fields in proximity to the radiator. The results confirm that the proposed feeding mechanism is suitable to have frequency-insensitive behavior and induces strong electric and magnetic field strengths for higher radiation gain in extremely small antenna arrays.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.1
• /
• pp.55-64
• /
• 2016

The development of high-speed rail (HSR) has had a major impact on the power supply grid. Based on the monitored waveforms of HSR, a pattern recognition approach is proposed for the first time in this paper to identify the operating conditions. To reduce the data dimensions for monitored waveforms, the principal component analysis (PCA) algorithm was used to extract the characteristics and their waveforms from the monitored waveforms data. The dynamic time wrapping (DTW) algorithm was then used to identify the operating conditions of the HSR. Cases studies show that the proposed approach is effective and feasible, and that it is possible to identify the real-time operating conditions based on the monitored waveforms.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2005.11a
• /
• pp.367-370
• /
• 2005

In this paper, we made a Singly Fed patch which is the fittest at the feeding part. And we found out return loss and radiation pattern about dielectric rod array antenna which has six's passive element to shape FTEP(Flat-topped element pattern) after we analyzed the characters of singly dielectric rod antenna. We show the conclusion that has the optimum return loss and more flat radiation pattern.

• Journal of electromagnetic engineering and science
• /
• v.8 no.1
• /
• pp.1-5
• /
• 2008

In this paper, a biconical type antenna is proposed for EMI test site validation above 1 GHz. To achieve broadband and omni-directional radiation patterns required by international standard(CISPR), the proposed antenna consists of general bicones with cylindrical loads and adopts side feeding method to minimize the influence on H-plane pattern due to feeding cable, balun, and connector. The radiation patterns of the fabricated antenna are measured and the results are compared with CISPR criteria and commercial antenna in our interest frequencies. Although the proposed antenna has a few problems in frequency range of 1 GHz to 2 GHz, it has relatively better performance than commercial antenna.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.4
• /
• pp.634-639
• /
• 2015

In order to understand phenomenon of the electric railway power feeding system in the construction planning step, analysis of the overall system including electric characteristic of electric railway power feeding system, train running characteristic and power consumption pattern and train operation plan and gradients of railroad and curve radius is required. This paper study the feeder system by analysis of comprehensive system according to train operation plans, line impedance, running characteristic of train, electrical properties of the feeder system. In order to understand phenomenon to the feeder system of tram exactly regarding export of the field railroad preceeding actively recently.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.5
• /
• pp.355-365
• /
• 2017

In this paper, we propose the design of a dual-band GPS antenna using in-direct feeding pads. The antenna consists of an upper patch for the GPS L1 band, a lower patch for the GPS L2 band, and two pads on the middle layer for feeding the two radiating patches. A hybrid chip coupler with a phase difference of $90^{\circ}$ is employed at the two feeding ports for achieving a broad circular polarization (CP) bandwidth. The proposed antenna shows bore-sight gains of 3.0 dBic(L1) and 5.1 dBic(L2), and axial ratios of 3.3 dB(L1) and 0.3 dB(L2) by measurement. The active element patterns of the fabricated array with 7 elements show bore-sight gains of -0.4 dBic (L1) and -2.4 dBic(L2), respectively. It proves that the proposed antenna structure is suitable for use in GPS array applications.

• Korean journal of applied entomology
• /
• v.44 no.4 s.141
• /
• pp.271-276
• /
• 2005

To investigate feeding behaviour of the greenpeach aphid (Myzus persicae) on several plants, DC electrical penetration graph (EPG) technique was used. We chose 5 plants including pepper, melon, cabbage, radish, and eggplant which were known as major host Plants of this species. This study was focused whether feeding patterns of the aphid were different and which plants would be the most preferable among 5 host plants. The time from initial proboscis contact with a each leaf until the first electrical contact, as a measure of the time taken for the stylet penetration, the time from electrical contact to the first potential drop as a time consumed until intracellular sampling, the number of potential drops per an hour during periods of regular intercellular pathway probing, and the time from electrical contact to tile first phloem specific pattern indicating the time taken to reach and attempt to feed upon the phloem were analysed. As a result, except the number of potential drop, there was no significant differency of feeding patterns among 5 plants. However, the feeding patterns related on host acceptability were observed more frequently from Pepper, radish, and e99r1an1 than melon and cabbage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.2
• /
• pp.140-147
• /
• 2011

In this paper, we propose a novel feeding method that uses a windshield ground in a vehicle. The feeding method enables for various antennas to integrate easily in a vehicle windshield. To connect a coaxial feeding cable directly to the windshield ground, we inserted a coaxial-to-ground adapter between the cable and the ground, and reflection coefficients using the proposed feeding method were compared to that using a conventional feeding method. The size and position of the windshield ground were optimized in order to achieve a high radiation gain in the azimuth direction. Then the triangular WiBro patch antenna, incorporating the proposed feeding method, was designed and installed on a rear windshield of a commercial sedan. The antenna using the proposed feeding method shows a similar reflection coefficient, and it shows 2 dB increased average azimuth radiation gain compared to that using a conventional sash ground method. These results demonstrate that the proposed feeding method can be applicable for integrating multiple antennas in a rear windshield.