• Title/Summary/Keyword: 미약신호

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A Study of Developing Band Pass Filter for Radio Astronomy Equipments (전파천문 기기용 BPF의 개발에 관한 연구)

  • Lee Je-Hun;Kim Dong-Il;Che Seung-Hun;Song Young-Man
    • Journal of Navigation and Port Research
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    • v.30 no.5 s.111
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    • pp.363-367
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    • 2006
  • The frequency band $10.5GHz\sim10.7GHz$ provides some of the best angular resolutions using many large and accurate radio telescopes. Developing high performance Bandpass Filter is needed for these equipments to receive low power signals from the space. In this paper, suggests Bandpass Filter for Radio Astronomy equipments. Designed by Microstrip Line for good pass characteristic and suppressing not necessary signals cause of using high frequency. Center frequency is 10.6 GHz and band width is 5% of Center frequency. Manufactured Bandpass Filter is suitable for Radio Astronomy Equipments. Bemuse it matches up to the result by simulate.

The tradition and musical aspect of the Saeteo-gaeulgut-nori(Play) (새터가을굿놀이의 전승과 음악적 양상)

  • Seo, Jeong-Mae
    • (The) Research of the performance art and culture
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    • no.38
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    • pp.111-142
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    • 2019
  • Saeteo-gaeulgut-nori(Play) is derived from the fact that the folk song that was played when harvesting in the Shinhori (aka Satter) in Chongdong, Miryang City was associated with the play and played a sacrificial feast at the end of autumn threshing. Saeteo-gaeulgut-nori(Play) consists largely of three chambers. The first one is the entrance gut, 2) the second one is SeonghwangGosa(城隍告祀), 3) the sound of bench threshing(空床 打作), 4) the harvesting chapter 5) the dry grass threshin, 6) the wooden millstone play, and the third one is 7) Pan-gut. Milyang has developed a sense of agriculture to the extent that both the Sangwon play and the Jungwon play are designated as intangible cultural properties. Especially, since the tradition of the House of Representatives is weak nationwide, the status of Milyang Saeteo-gaeulgut-nori(Play) has a very important value. The overall sound of the autumn good play is that the characteristics of Gyeongsang Folk Song are rooted in the structure of the menaritri, It has the characteristics of folk songs well.

A Study on Speech Recognition Estimation of Cochlea Dead Region and Amplification Gains According to Frequency Bands (주파수 영역별 Cochlea Dead Region과 증폭 이득에 따른 어음인지능력 평가 연구)

  • Park, G.S.;Bang, D.H.;Lee, S.M.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.5 no.1
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    • pp.41-46
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    • 2011
  • A sensorineural hearing loss(SNHL) occurs when the cochlea in the inner has functional problem. The region in the cochlea with no(or very few) functioning inner hair cells or neurons called 'dead regions'. Amplification using hearing aid over a frequency range corresponding to a dead region may not a beneficial. In this paper, we compared speech recognition with different location of dead region and gain and searched effective gain for hearing aid with dead region. In order to experiment, eight people who has normal hearing ware tested, and we used white noise and babble noise(SNR=0 dB). we divided by three conditions, low, mid and high frequency dead region. In addition, the gains in dead region ware 14.5 dB, 11.5dB and 6 dB gain. There ware different results by location of dead region. The result of WRS and preference in mid-frequency dead region and high-frequency dead region ware higher than them in low-frequency dead region. When we compared as gains, the score of WRS with lower gain was higher than 14.5 dB gain, and the preference was lower as higher gain.

Effect of Borehole Fluid and Casing on the Borehole Electromagnetic Responses (공내수 및 케이싱이 시추공 전자탐사 반응에 미치는 영향)

  • Cho Seong-Jun;Kim Jung-Ho;Yi Myeong-Jong;Chung Seung-Hwan;Song Yoonho
    • Geophysics and Geophysical Exploration
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    • v.2 no.2
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    • pp.104-111
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    • 1999
  • As a practical developing step of electromagnetic (EM) tomography technique, we quantitatively analyzed the effects of borehole fluid and casing on the borehole EM responses. The EM response turns out to have nothing to do with the property of the borehole fluid except in the close vicinity of the transmitter, which shows the wide perspective of the application of borehole EM. Single-hole responses in the presence of the steel casing throughly reflect those of the casing itself since its extremely high induction number or shallow skin depth. EM responses through steel casing do show the information of the host medium. In the near field region which corresponds to low frequency or the vicinity of the borehole, however, we can not separate the signal containing the information of the host from that of casing. Otherwise, the severe attenuation of energy in the casing at high frequencies renders the signal undetectable. The optimum frequency is, therefore, to be chosen to extract the information of the host considering both the property of the casing and the skin depth of the medium and the practical technique to determine the casing property through single-hole measurements is required.

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Distinction of Internal Tissue of Red Ginseng Using Magnetic Resonance Image (MRI을 이용한 홍삼 내부조직 판별)

  • Kim, Chun-Suk;Jung, In-Chan;Kim, Se-Bong
    • Journal of Ginseng Research
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    • v.32 no.4
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    • pp.332-336
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    • 2008
  • Red ginseng is classified according to outer form and the quality of internal tissue, and red ginseng below third grade can't be sold. Also there are many differences in price according to grade. So if inferior Red ginseng is sold, economic loss and claim take place. This research is done conducted to investigate the possibility of the non-destruction internal tissue investigation of red ginseng. It is observed and compared that MR image after getting MR image agrees with real cutting side in 10-13% water content of red ginseng. The MR image can be obtained to see the internal section of red ginseng with equal condition of time, temperature and slice thickness in spin echo pulse sequence. The MR signal of red ginseng is very weak, because it contains low water density. So it takes about 30 minutes with the measurement of single point image (SPI). But the suitable time to distinguish internal tissues is about 9 seconds in TE (Echo Time) 2.23 ms, TR (Repetition Time) 150ms. The image to discriminate internal tissues in 9 seconds can be obtained when slice thickness is 10 mm with changes of 3, 5, 10 mm. The image obtained after 30 minutes' boiling of 55 degrees has clearer image than that of normal temperature. It is thought that MR signal is stronger through active motion of water particles as temperature increases. With this method MR image of red ginseng can be obtained and characteristics of internal tissues can be observed in such a short time.

Magnetic Resonance Imaging Feature of Bacterial Meningitis in a Neonate Hanwoo Calf (한우 송아지에서 세균성 뇌막염의 자기공명영상)

  • Cho, Young-Kwon;Kim, Jin-Won;Kim, Jae-Hoon;Kim, Jae-Hoon;Lee, Ki-Chang
    • Journal of Veterinary Clinics
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    • v.26 no.6
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    • pp.650-654
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    • 2009
  • A 1-week-old, male Korean native calf with acute clinical signs of depression, mild diarrhea, ataxia, recumbency and tremor was referred to Chonbuk Veterinary Medical Center of Chonbuk National University. Vision loss and cornea edema were also observed on physical examination. The patient had been deteriorated with nystagumus, strabisumus and opisthtonus. Blood cell count test and blood biochemistry test revealed remarkable leukocytosis, and hypoalbuminemia and increased blood urea nitrogen. No remarkable findings were observed on radiography. On magnetic resonance imaging study, there were enlarge lateral, third, and forth ventricles. The cortical grey and subcortical white matter of left temporal lobe showed hypointense on T1-weighted images and hyperintense on T2-weighted images, and slightly enhanced on contrast-enhanced T1-weighted images. Escherichia coli strain was identified from cerebrospinal fluid sample. Palliative treatment was attempted but the neonatal calve was expired three days after admission. Severe multifocal fibrino-suppurative meningitis with Escherichia coli infection was confirmed histopathologically.

Frequency Sounding in Small-Loop EM Surveys (소형루프 전자탐사법에서의 주파수 수직탐사)

  • Cho In-Ky;Lim Jin-Taik
    • Geophysics and Geophysical Exploration
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    • v.6 no.3
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    • pp.119-125
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    • 2003
  • The small-loop electromagnetic (EM) technique has been used successfully for many geophysical investigations, particularly for shallow engineering and environmental surveys. In conventional small loop EM operating at small induction numbers, geometric sounding has been widely used because the depth of penetration of EM energy depends only on the source-receiver separation. Recently developed small loop EM system, however, measures the secondary magnetic field, $H^S$, at multiple frequencies with a fixed source-receiver separation and frequency sounding is tried actively. In this study, we analyzed the behavior of in-phase and quadrature components of ${H^S}_z$, for horizonal coplanar (HCP) configuration over two-layer models. Through this theoretical analysis, it was found that the in-phase component of ${H^S}_z$ is more suitable for frequency sounding than the quadrature component. But, the in-phase component of ${H^S}_z$ is too small to measure, especially in resistive and noisy environment like Korea. Using the fact that the quadrature component is much greater than the in-phase component and the difference of quadrature component of ${H^S}_z$ measured at two frequencies shows the same behavoir as the in-phase component, we suggested an alternative frequency sounding technique. Also, we defined an apparent conductivity, which reflects well the conductivity of subsurface layers.

Location Estimation System based on Majority Sampling Data (머저리티 샘플링 데이터 기반 위치 추정시스템)

  • Park, Geon-Yeong;Jeon, Min-Ho;Oh, Chang-Heon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2523-2529
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    • 2014
  • Location estimation service can be provided outdoors using various location estimation system based on GPS. However, location estimation system is based on existing indoor resources as GPS cannot be used because of insufficient visible satellites and weak signals. The fingerprinting technique that uses WLAN signal, in particular, is good to use indoors because it uses RSSI provided by AP to estimate location. However, its accuracy may vary depending on how accurate data the offline stage used where the fingerprinting map is built. The study sampled various data at the stage that builds the fingerprinting map and suggested a location estimation system that enhances its precision by saving the data of high frequency among them to improve this problem. The suggested location estimation system based on majority sampling data estimates location by filtering RSSI data of the highest frequency at the client and server to be saved at a map, building the map and measuring a similar distance. As a result of the test, the location estimation precision stood at minimum 87.5 % and maximum 90.4% with the margin of error at minimum 0.25 to 2.72m.

Optimum Configuration of Single Frequency Network DMB to enhance the QoS and Service coverage (QoS 개선과 서비스 커버리지 확장을 위한 단일 주파수망 지상파 DMB 최적화 배치)

  • Cho, Young-Hun;Won, Chung-Ho;Seo, Jong-Soo
    • Journal of Broadcast Engineering
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    • v.19 no.4
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    • pp.439-452
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    • 2014
  • This paper suggests the method to extend service area by using the transmit offset delay in T-DMB single frequency network (SFN). In general, synchronization of the transmit time of all site can be done by using the reference clock of GPS, which dose not reflect the details geographical characteristics and transmit specifications of each site. Applying the site-specific transmit offset delay, we could extend the service area of SFN T-DMB. Applying the transmit offset delay, it is found that the signal quality in the region of weak receive field strength was improved and upto 4~8 km service area expansion was achieved by satisfying the minimum field strength ($45dB{\mu}V/m$) recommended by the Korea Communications Commission (KCC). Site-specific offset delay was calculated considering the geographic service area characteristics, distribution of electric field strength between neighboring sites and site-specific service target area. Experiments were carried out in order to analyze impact of calculated offset delay on the T-DMB SFN and also to confirm that the offset delay extends T-DMB service coverage. The experiment was done in metropolitan T-DMB service areas.

Image Registration and Fusion between Passive Millimeter Wave Images and Visual Images (수동형 멀리미터파 영상과 가시 영상과의 정합 및 융합에 관한 연구)

  • Lee, Hyoung;Lee, Dong-Su;Yeom, Seok-Won;Son, Jung-Young;Guschin, Vladmir P.;Kim, Shin-Hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.6C
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    • pp.349-354
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    • 2011
  • Passive millimeter wave imaging has the capability of detecting concealed objects under clothing. Also, passive millimeter imaging can obtain interpretable images under low visibility conditions like rain, fog, smoke, and dust. However, the image quality is often degraded due to low spatial resolution, low signal level, and low temperature resolution. This paper addresses image registration and fusion between passive millimeter images and visual images. The goal of this study is to combine and visualize two different types of information together: human subject's identity and concealed objects. The image registration process is composed of body boundary detection and an affine transform maximizing cross-correlation coefficients of two edge images. The image fusion process comprises three stages: discrete wavelet transform for image decomposition, a fusion rule for merging the coefficients, and the inverse transform for image synthesis. In the experiments, various types of metallic and non-metallic objects such as a knife, gel or liquid type beauty aids and a phone are detected by passive millimeter wave imaging. The registration and fusion process can visualize the meaningful information from two different types of sensors.