• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.129-133
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• 2004

In the past, radio astronomers have sought isolation from man-made signals by placing their telescopes in remote locations. These measures may no longer safeguard scientific observations, since NGSO satellite systems, particularly low-Earth orbit (LEO) systems, are usually designed to provide global or wide regional coverage. Further, radio astronomers have historically made their observations in the frequency bands allocated for their use by the member countries of the International Telecommunication Union (ITU). The science of radio astronomy could be adversely impacted by the deployment of large constellations of new non-geostationary orbiting (NGSO) satellites for telecommunications, navigation and Earth observation, and the proliferation of new, high-power broadcasting and telecommunication satellites in geostationary (GSO) orbits. Radio telescopes are extremely sensitive, and, in certain situations, signals from satellites can overwhelm the signals from astronomical sources. This paper describes the problem in detail and identifies ways to mitigate it without adversely affecting the continued vigorous growth of commercial space-based telecommunications.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.8-12
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• 2003

To protect digital communications and broadcasting that are expected to be increasingly used at frequencies above 1GHz, there is a need to determine permissible disturbance limits for frequency bands above 1GHz according to indicates that better correlates with interference level in digital systems. The quality of digital communications is expressed in terms of bit error rate(BER) or throughput. In this regard, it has been reported that degradation of BER or throughput can be estimated from the amplitude probability distribution (APD) of disturbance amplitude. Therefore, if the APD can simply be measured with a high accuracy, APD will be an optimal index for the assessment of interference in digital communications. In this paper, we show that a measurement method using statistic model of APD has compatibility about performance reduction estimation of WLAN. And through approach of this inspection, we propose numeral models about interference effects of peak value and time rate of spurious.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.740-746
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• 2001

Radio interferences have been a frequent problem on the TRS service, which has been in operation in the southern coastal area of Korea since 1994. By Korea-Japan joint analysis, the main reasons of the radio interferences are due to the radio ducting signal from the seaside of Japan. As the mobile services become spreading in China as well as Japan, interference problems between Korea and China will occur more frequently in various frequency bands. Therefore, in this paper we propose a method for measurement and analysis of the radio interference signal, and summarize the measurement results of interference from China, which was performed to solve the interference problem between Korea and China.

• Journal of electromagnetic engineering and science
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• v.6 no.4
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• pp.235-243
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• 2006

In this paper, the fractal shape is applied to microstrip band pass filters and integrated on a high-resistivity Si substrate to solve conventional $2^{nd}$ harmonic problem. Conventional microstrip coupled line filters are popular in RF front ends, because they can be easily fabricated and integrated with other RF components. However, they typically have large second harmonics that can cause unwanted interference in interested frequency bands. Without any additional filters, the proposed Koch shape filters have suppressed the $2^{nd}$ harmonics by about -40 dB, so they can be used in systems such as direct conversion receiver with stringent harmonic suppression requirements.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.23-26
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• 2000

In order to develop the specific genetic marker for Korean native cattle (Hanwoo), randomly amplified polymorphic DNA (RAPD) analysis of 6 different cattle breeds was attempted by using 38 decamer primers. In comparison of RAPD patterns, two distinctive DNA bands specific for Hanwoo were detected. One was 296 bp of DNA fragment found to be specific only for female Hanwoo when primer GTCCACACGG was employed. In individual analysis of this RAPD marker was observed only in female individuals with the possibility of $85.3\%$. The other was 521 bp of RAPD marker amplified using TCGGCGATAG and AGCCAGCGAA primers, which showed $83.0\%$ of genetic frequency in 85 male and 68 female individuals tested. Nucleotide sequencing of these genetic markers revealed that 296 bp marker has a short micro satellite-like sequence, ACCACCACAC, and a tandem repeat sequence of microsatellite GAAAAATG in the determined sequence. Two distinctive tandem repeats of microsatellite sequences, MC and GAAGA, were also appeared in 521 bp DNA marker. In BLAST search, any gene having high homology with these markers was not found.

• Fashion & Textile Research Journal
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• v.8 no.6
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• pp.618-626
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• 2006

This research explored the actual conditions, problems and design preferences of dementia inpatient clothing. Data were collected by surveying 21 dementia hospitals and nursing care facilities and 87 caregivers and nurses of dementia hospitals. The collected data were analysed through frequency analysis, descriptive analysis and factor analysis. The results were as follows, First, the inpatient clothes of dementia hospitals were two-piece styles, the shirts of front opening with buttons and pants of no opening with elastic band. Those of dementia care facilities were two piece styles of shirts and pants, training suits or private plain clothes not uniform. Severe dementia inpatient dressed uniforms of the jump suits or two piece styles in some dementia care facilities. Second, the problems of dementia inpatient clothing were composed of suitability of raw and subsidiary clothing material, diversity of design and size, durability and form stability of clothes and elastic bands. Third, the design elements similar to those of existing inpatient clothing were preferred with regard to improving dementia inpatient clothing. That is, the design preferences of shirts showed front opening style with buttons, round neckline and a three-quarter-length sleeves. Those of pants came out no opening style with elastic band and full length. Also, pink color and natural patterns were preferred, and the private plain clothing of inpatient and fusion Han-bok style were somewhat preferred.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.461-469
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• 2014

Polychlorinated biphenyls (PCBs) are persistent pollutants in aquatic environments, often causing the decline or disappearance of wild populations. In this study, we used a random amplified polymorphic DNA (RAPD) assay to evaluate the effects on the genomic DNA of olive flounder embryo and larval stages of exposure to Aroclor 1254 at concentrations of 1, 5, 10, 20, and $40{\mu}g/L$. We compared RAPD fingerprints of exposed and non-exposed samples. Polymorphisms were revealed as the presence and/or absence of DNA fragments between the two samples. A dose-dependent increase in the number of polymorphic bands was observed with Aroclor 1254 treatment. Also, RAPD profiles of animals exposed to Aroclor 1254 exhibited an increase in the frequency values (FV) compared to the control. A phenogram constructed using neighbor-joining method indicated that genomic template stability in developing embryo and larval stages was significantly affected at ${\geq}5{\mu}g/L$. This study suggested that DNA polymorphisms detected by RAPD analysis could be used as an investigative tool for environmental toxicology and as a useful biomarker in early life stages for the detection of potential genotoxicants.

• Journal of the Korea Computer Industry Society
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• v.5 no.2
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• pp.331-336
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• 2004

In this paper, an antenna for telematics is proposed. It operates at GPS/GSM frequency-bands and it can be installed inside of a vehicle. There is a great difference between the proposed antenna and commonly used antennas. It needs not to use a dielectric with a high permittivity since it is formed on a sheet of FR4 with only 1mm thickness. Thus, it is possible to cut costs and make process of manufacture simple. Planar inverted-F antenna(PIFA) for GSM and microstrip antenna(MSA) for GPS is designed and PIFA-MSA antenna is proposed. The height is lower than that of commonly used antennas. And polarization of the PIFA and MSA is arranged perpendicularly for isolation improvement of each port, thus isolation of these two antennas is improved. Also, it is sufficient for the all specifications.

• The Journal of the Acoustical Society of Korea
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• v.23 no.6
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• pp.481-487
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• 2004

In this paper. the structure of bandwidth scalable wideband speech codec and its high-band codec are proposed. In the high-band codec. the signal is divided into frequency bands. and each band is quantized in DCT domain. The DCT coefficients are splitted into magnitude and sign, and each is quantized independently by a specialized method based on its characteristics. In addition. the quantized gain parameter in the low-band codec is utilized in the high-band codec for an enhanced performance. The bandwidth scalable wideband speech codec using G.729E for low-band and the proposed codec for high-band is developed, and it is confirmed that the proposed codec has better subjective performance than 24kbps G.722.1.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1653-1658
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• 2011

A novel circuit structure of dual-band bandstop filters is proposed in this paper. This structure comprises two shunt-connected tri-section stepped impedance resonators with a transmission line in between. Theoretical analysis from the equivalent circuit and design procedures are described. We represented graphs for filter design from the derived synthesis equations by resonance condition of circuits. Notably, advantages of the proposed filter structure are compact size in design, wide range of realizable resonance frequency ratio, and more realizable impedances.