• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.101-104
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• 2009

이 연구는 Ka대역 위성 HDTV 방송 서비스를 제공하기 위해 강우강도에 따른 전송방안을 제안하였다. Ka대역은 Ku대역에 비하여 강우에 취약하기 때문에 이를 안정적으로 활용하기 위해서는 강우감쇠를 효과적으로 경감시키는 기술개발이 필수적이다. 유럽위성방송 표준인 DVB-S2에서는 강우감쇠에 대한 대처방안으로 채널상황에 따라 여러 변조방식과 채널 부호 율을 이용하는 적응형 변복조 방식을 지원하고 있으며, 이 논문에서는 DVB-S2기반의 전송방식과 Ka대역 중계기의 규격을 적용하여 강우강도에 따른 전송방안을 제안하였다. 이를 위하여 ITU-R P.618-9 강우감쇠 추정 모델과 기상청에서 측정한 1998년부터 2007년까지의 최근 10년간 국내 주요지역의 30분 누적강우량을 이용하여 지역별 강우 감쇠값을 도출하였고 강우강도와 시간 율 관계분석을 통하여 강우강도에 따른 강우감쇠 값을 획득하였다. 획득한 강우감쇠 값을 무궁화 위성 3호의 링크 설계에 적용하여 강우강도에 따른 적용 가능한 전송방안을 도출하였다. 이 연구를 바탕으로 강우의 지역적 편이가 높은 우리나라의 강우 특성을 유연하게 반영하여 각 지역에 맞는 적응적인 전송 방식을 고려할 수 있다.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.58-63
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• 2013

Since radio interference can degrade the performance of systems or limit the system operation, an accurate assessment of radio interference with the existing systems should be conducted prior to the operation of a new system. In this paper, we present an evaluation methodology for the radio interference between radio-navigation satellite service (RNSS) systems and mobile communication service (MS) system. Radio interferences from RNSS systems into MS system using minimum coupling loss (MCL) method are simulated and vice-versa, and the frequency sharing condition between two systems are derived in a same geographical area.

• Progress in Superconductivity
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• v.2 no.1
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• pp.51-55
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• 2000

A $Y_1Ba_2Cu_3O_{7-\delta}$ square spiral microstrip antenna (YBCO antenna) was epitaxially grown on a $LaAlO_3$ substrate by laser ablation. Also fabricated was a gold square spiral microstrip antenna (gold antenna) having the same structure as that of the YBCO antenna in order to compare the properties of both antennas. Both the YBCO antenna and the gold antenna were operated in Ku (12-18 GHz) band, and their properties such as the return loss, SWR, power gain, and radiation patterns were investigated at 77 K. The return loss below -10 dB was obtained in two frequency ranges, i.e., 14.05-14.90 GHz, and 16-18 GHz for the YBCO antenna at 77 K (YBCO superconducting antenna), and in the frequency range of 15.05-17.60 GHz for the gold antenna at 77 K. The SWR bandwidths are 0.85 GHz and 2 GHz for the YBCO superconducting antenna, and 2.55 GHz for the gold antenna at 77 K. The gain improvement of the superconducting YBCO antenna over the gold antenna at 77 K was about 10 dB in the frequency range of 16 GHz to 18 GHz. The radiation patterns show the YBCO superconducting antenna has the omni-directional property of a spiral antenna.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.290-293
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• 2012

This article introduces the characterization of spin coated ZnO transparent conducting oxide on the flexible substrates. As a II-IV compound semiconductor, ZnO has a wide band gap of 3.37 eV with transparent properties. Due to this transparent properties, ZnO materials can be also employed as the transparent conducting electrode materials. Therefore, strong demands have been required for the transparent electrodes with low temperature processing and cheap cost. So, We will investigate the electrical property and optical transmittance of ZnO transparent conducting oxide through the 4-point probe resistivity meter, and ultraviolet-vis spectrometer Lamda 35, respectively.

• Preventive Nutrition and Food Science
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• v.15 no.2
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• pp.159-166
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• 2010

The aim of this study was to develop species-specific primer sets for kimchi Lactobacillus. Known gene sequences of Lactobacillus 16S rRNA were collected from the NCBI Gene bank, and 69 primer sets were designed using the homologous gene sequence. Six species of kimchi Lactobacilli were used as reference strains: Lactobacillus brevis KCTC3102, Lactobacillus farciminis KCTC3681, Lactobacillus fermentum KCTC3112, Lactobacillus hilgardii KCTC3500, Lactobacillus plantarum KCTC3099, and Lactobacillus sanfranciscensis KCTC3205. PCR amplification and gel electrophoresis were performed to identify the accuracy and specificity of the developed primer set. The results show that the primer set of 5'-aagcctgcgaaggcaag-3' & 5'-aggccaccggctttg-3', 5'-acatactatgcaaatctaagagattagacg-3' & 5'-actgagaatggctttaagagattagcttac-3' resulted in a specific PCR band on L. hilgardii, and primer set of 5'-ctaataccgcataacaactactttcacat-3' & 5'-aacttaataaaccgcctacattctctttac-3' on L. farciminis. The results indicate that the developed primer sets can provide a useful tool for the identification and differentiation of L. hilgardii and L. farciminis from other Lactobacillus species of kimchi.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.323-330
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• 2018

In this paper, design and fabrication of a MSP(Multiple Scattering Points) discriminator for a simulated target measurement using a HRR(High Range Resolution) RADAR are described. The MSP discriminator is designed to provide a reference signal at the installed point on the simulated target in an outdoor test. The MSP discriminator is designed to have a remote control function that can turn the MSP discriminator on and off when the target moves to a remote location. While the MSP discriminator is off, the MSP discriminator is designed to be small enough not to spoil the target's unique RCS. The MSP discriminator consists of RF components in the Ku-band. In order to prevent spreading of the signal, a cable were added to the MSP discriminator to have an appropriate feedback loop delay considering the resolution of the RADAR. The fabricated MSP discriminator provided a reference scattering point as an RCS of approximately 1 dBsm. As a result, by using the MSP discriminator, the physical scattering points of the target were clearly identified in the measured signals with the RADAR.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.862-869
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• 2006

The purpose of this study is to propose the proper vocabularies for evaluating H.D TV set fan noise in residential condition. To achieve this goal, psycho-acoustic experiments were carried out with TV set fan noise modulated at specific frequency band. finally, a correlation analysis between vocabularies, and a factor analysis of psycho-acoustical responses were conducted. As a result of this study, followings are suggested. Analyzing the psycho-acoustical response corresponding to the various sound level, the higher the sound levels, the higher the response values were. It is estimated that the sound level determined psycho-acoustical responses. On the degree of response to fan noise, the initial level of negative feeling is located on $35{\sim}40$ dB(A). The factor of evaluating H.D. TV set fan noise has induced three the appropriate korean adjectives; Irritate, Monotonous, stuffy and dryness. The result of this study may be used to evaluate the acoustic threshold level for indoor noise or a basis for specifying the desired acoustic environment of dwellings.

• Clinics in Shoulder and Elbow
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• v.9 no.1
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• pp.124-129
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• 2006

Distal clavicular fracture frequently requires operative treatment due to high rate of non-union. The operative technique includes the tension band wiring, K- wire fixation, and cerclage wiring etc. Each method has disadvantages somewhat like pin migration or acromioclavicular joint injury and so on. For the distal clavicular fracture type 2a, because of its oblique fracture line, the cerclage wiring is suitable. We performed the cerclage wiring percutaneously under minimal incision without injury to periosteum for the patient who had the distal clavicular fracture type 2a, and the result was favorable.

• Korean Journal of Materials Research
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• v.30 no.8
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• pp.399-405
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• 2020

In the present investigation we show the effect of Al doping on the length, size, shape, morphology, and sensing property of ZnO nanorods. Effect of Al doping ultimately leads to tuning of electrical and optical properties of ZnO nanorods. Undoped and Al-doped well aligned ZnO nanorods are grown on sputtered ZnO/SiO₂/Si (100) pre-grown seed layer substrates by hydrothermal method. The molar ratio of dopant (aluminium nitrate) in the solution, [Al/Zn], is varied from 0.1 % to 3 %. To extract structural and microstructural information we employ field emission scanning electron microscopy and X-ray diffraction techniques. The prepared ZnO nanorods show preferred orientation of ZnO <0001> and are well aligned vertically. The effects of Al doping on the electrical and optical properties are observed by Hall measurement and photoluminescence spectroscopy, respectively, at room temperature. We observe that the diameter and resistivity of the nanorods reach their lowest levels, the carrier concentration becomes high, and emission peak tends to approach the band edge emission of ZnO around 0.5% of Al doping. Sensing behavior of the grown ZnO nanorod samples is tested for H₂ gas. The 0.5 mol% Al-doped sample shows highest sensitivity values of ~ 60 % at 250 ℃ and ~ 50 % at 220 ℃.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.97-103
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• 2010

In this paper, we present an efficient design scheme based on analysis of design requirements and considerations of baseband packet switch for S-band satellite/terrestrial hybrid multi-beam satellite communication systems. To establish design requirements and considerations, we analyze required functions of baseband packet switch, specifications of multi-beam satellite communications, communication services and performance requirements. And also we analyze and compare conventional layer-2 and layer-3 satellite baseband packet switching techniques, packet switching protocols and packet switch architectures, to apply from analyzed results. Finally, we propose a hardware design scheme of MPEG based layer-2 baseband packet switch using analyzed results.