• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.943-953
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• 2007

In this paper, we propose a Cassegrain antenna with a scalar feed horn opt rating in Ka-band. For an effective EM simulation of the Cassegrain antenna, the near-field of the feed hone is used ai the equivalent source of the Cassegrain antenna using the surface equivalent theorem. A corrugated circular horn operating with $HE_{11}$ mode is used as the feed horn. The angle and feed center of the main and sub reflectors are optimized to achieve maximum antenna efficiency. The designed feed horn shows the gain of 19dBi, the side-lobe level of less than -25dB and the half power beam width of $20^{\circ}$ at 33 GHz. The Cassegrain antenna shows the gain of 41dBi, the efficiency of 60%, the side-lobe level of less than -20dB and the half power beam width of $1.2^{\circ}$.

• The Plant Pathology Journal
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• v.16 no.6
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• pp.297-305
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• 2000

Weeds are widely grown in the field and are infected by many viruses. A survey was conducted to identify viruses infecting weeds in Korea. Virus-infected weed samples including Rorippa indica (L.) Hiern, R. islandica (Oed.) Bord, Crepidiastrum denticulatum (Houtt.) Pak & Kawanno, Achyranthes japonica (Miq.) Nakai, and Chrysanthemum boreale (Makino) Makino were collected in Kyonggi Province. These weeds were grown in the greenhouse and were isolated on 10 test plants. Several virus isolates were isolated fron infected tissues and were further studied by host range assay, serological test, electron microscopy (EM), reverse transcription-polymerase chain reaction (RT-PCR) and sequencing. Each isolated virus strain was mechanically transmitted to weeds and various hosts including Nicotiana spp., Brassica spp., Vigna unguiculata, Capsicum annuum, and Cucumis sativus and showed systemic mosaic, vein clearing, necrosis, mottle, malformation, chlorosis, and/or death of host plants in some cases. Each virus was then purified using infected leaves and observed by EM. From these results three viruses were isolated and identified as Turnip mosaic virus (TuMV), Broad bean wilt virus (BBWV), and Cucumber mosaic virus (CMV). RT-PCR using virus-specific oligonucleotide primers and the cloning were conducted to determine the nucleotide sequences of coat proteins of the three viruses their amino acid sequence were deduced. The amino acid sequence homologies were about 92.7 to 99.7%, 96.2 to 97.7%, and 93.9 to 98.6% to other reported TuMV, BBWV, and CMV strains, respectively. These results suggest that many weeds may serve as primary inoculum source of diseases caused by TuMV, BBWV, CMV and that the management of these viral diseases can be achieved through weed control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.131-139
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• 2018

Many ship researches have been carried out in connection with the fourth revolution, one of which focuses on EMS(energy management system). The EMS is referred to as systems for managing the energy of ships and include various systems. In this paper, we analyze the energy saving field in ship and propose a ship power energy management system including individual load control systems that can save energy in the engine room. EMS includes individual load control systems of PCS (Pump Control System), ERFCS (Engine Room Fan Control System), LCS (Load Control System), HVACS (Heating, Ventilation, Air conditioning Control System). Proposed EMS primarily conserves energy in the individual load systems of the engine room. Secondly, the integrated monitoring and control system is used to control the power generation system and the power load system to save energy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1155-1163
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• 2011

In this paper, we propose a new pre-processing algorithm applied to depth map to improve the coding efficiency. Now, 3DV/FTV group in the MPEG is working for standard of 3DVC(3D video coding), but compression method for depth map images are not confirmed yet. In the proposed algorithm, after dividing the histogram distribution of a given depth map by EM clustering method based on GMM, we classify the depth map into several layered images. Then, we apply different mean shift filter to each classified image according to the existence of background or foreground in it. In other words, we try to maximize the coding efficiency while keeping the boundary of each object and taking average operation toward inner field of the boundary. The experiments are performed with many test images and the results show that the proposed algorithm achieves bits reduction of 19% ~ 20% and computation time is also reduced.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.43-50
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• 2020

The Doam Lake watershed is one of the non-point source management areas announced by the Ministry of Environment, and is a constant problem for the stream ecosystem dut to Storm water. In this study, a total of 48(rainfall) and 47(non-rainfall) sites were investigated for the entire watershed (Samyangcheon, Chahangcheon, Hoenggyecheon, Yongpyeongcheon, Songcheon, Lake Doam) on August 15, 2019 and on October 18, 2019 to estimate the source of turbid water in the Doam Lake watershed. Subsequently, water quality analysis was performed on Suspended Soild (SS), Turbidity, Total Phosphorus (TP), Total Nitrogen (TN), and Biochemical Oxygen Demands (BOD) and correlation among water quality parameters was analyzed based on the analyzed samples. As a result, most of the turbid water generated during rainfall was in highland fields. During rainfall, Hoengyecheon had the highest average SS concentration among all streams, and during non-rainfall, the average SS concentration was highest in Yongpyeongcheon, so the two stream were selected as vulnerable areas. However, since Yongpyeongcheon may be a temporary phenomenon due to river construction, additional continuous monitoring is required. Therefore, in the Doam Lake watershed, intensive management is required for vulnerable areas.

• International Journal of Railway
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• v.2 no.2
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• pp.93-97
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• 2009

The experiments for aerodynamic characteristics of railway acoustic screen are performed using 1/61 scaled-down moving model rig facility which employs an axis symmetry and one wire guidance method. The launching mechanism is an air-gun type. The train model for the experiment is the high speed train (Korea Train Express: KTX) and the tested speed is about 300 km/h. The tested train length is 61 em which is corresponding to two units of KTX train. The cross sectional area and weight of train model are 0.00264 $m^2$ and 287 g, respectively. The Reynolds number based on the model train length is $1.2{\times}10^7$. The strength of pressure wave is measured using piezo typed pressure sensor. The measured pick value of pressure was as high as 365 Pa in the shortest gap between the acoustic screen and model train. The measured pressure is well compared with the field test data of mc 779-1 [2] values. However, the experimental data were slightly lower than the mc 779-1 values. The results show the model test can be used as a substitute for the field test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.812-819
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• 2007

Acoustic Target Strength (TS) is a major parameter of the active sonar equation, which indicates the ratio of the radiated intensity from the source to the re-radiated intensity by a target. This research provides the time pattern of TS in time domain, which is applicable to pulse modulated acoustic pressure field. If the time pattern of TS is predicted by using TS equation in frequency domain, it takes long time and difficult since time function pulsed acoustic wave may be decomposed into their frequency domain components. But TS equation in time domain has a convenience. If the expression for pulsed acoustic field has been obtained, the problem can be solved. Furthermore this paper introduces about mathematical equivalence quantities between EM wave and Acoustic Wave.

• Animal Systematics, Evolution and Diversity
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• v.21 no.1
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• pp.21-30
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• 2005

The morphogenesis of the marine ciliate, Pelagostrobilidium simile Song and Bradbury, 1998, was investigated using pyridine silver carbonate impregnation. The morphogenesis of P. simile is of hypoapokinetal mode. The oral primordium of P. simile commences slightly below the external membranelles (EM) with the proliferation of an anarchic field. Somatic ciliature in proter and opisthe of P. simile are derived from the old structure with the proliferation of the basal bodies during the dividing process. Parental oral apparatus of P. simile is inherited by the proter, and no reorganization of oral apparatus was observed in the parental oral infraciliature.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.209-214
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• 2005

In the present age, the quality of MT(magnetotellurics) data highly depends on the level of industrial interference in data. We analyzed the correlation between the spatial distributions of man-made EM noise source and the characteristics of MT data. The noise source analysis shows the correlation between the noise source density and the power spectral density of measured magnetic field in the frequency band of 60 Hz harmonics. In the MT 'dead band', the strong polarization observed on the magnetic field reveals that the severe artificial noises are caused by the adjacent metropolis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.65-71
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• 2009

In this paper, we propose an aircraft on-glass antenna for FM radio reception. To obtain broad matching bandwidth, we employed a multiple loop as the basic antenna structure, and the shape of the loops mimics the frame of a window in order to ensure pilots' field of view as large as possible. The detailed design parameters of the multi-loop structure were determined using a Pareto genetic algorithm with a full wave EM simulation tool. The optimized on-glass antenna was built and installed on a Korean utility helicopter (KUH) The measurement results showed a half power matching bandwidth of about 63.3 %, average vertical bore-sight gain of about -12.98 dBi in the FM band.