• Title/Summary/Keyword: Antenna

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A Study on the Biology of Nesodiprion japonicus($M_{ARLATT}$) (솔잎벌의 생능에 관한 연구)

  • 이찬용;김인래
    • Korean journal of applied entomology
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    • v.33 no.2
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    • pp.60-65
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    • 1994
  • This study was carried out to investigate the ecology of Nesodiprion japonlcus (Mmm,m) damaging many conifers The results obtained were as follows: Nesod~prion japonicus (Maun) emerged two times for a year and their body was black m both sexes. A female (10.1t 1 2 mm) adult was larger than a male (9.9t 0.8 mm) one in the body size. The size of antenna as plumose of female was different from that of male. Life span of adults was 3 or 4 days, those emergence rate was 92% and sex ratio of female to male was 6: 4. Adults 1a1d only an egg in the leaf and the region of the leaf aviposited turned brown. Duration of egg was 14.35 1 2 days, egg was In the shape of banana and red~sh-yellow,a nd its sire was 2.4+ 0.2 mm long. Duration of larvae was 30.35 2.1 days and its slze 20.15 2.2 mm, body was green with grey~sh shipes on the dorsal and lateral aspect, the tip of front and hind was yellow and head was brown with a dark-p~gmented area. Mature larva turned into light green and get lost a dark-pigmented area of head. The firstly-emerged larva made cocoons on the base of leaves and the secondawemerged larva among fallen leaves Duration of prepupa was 14.3f 2.0 days and their size 10.15 2.3 mm Duration of pupa was 12.2+ 1.3 days and its size 10.lt0.2mm.

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Design of Ku-Band Low Noise Amplifiers including Band Pass Filter Characteristics for Communication Satellite Transponders (대역통과여파기 특성을 갖는 통신위성중계기용 Ku-Band 저잡음증폭기의 설계 및 제작)

  • 임종식;김남태;박광량;김재명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.5
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    • pp.872-882
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    • 1994
  • In this paper, the Low Noise Amplifier(LNA) is designed and fabricated to include a band pass filter characteristics considering the antenna system characteristics according to the transmitting and receiving signal level of communication satellite transponder. As an example, a 2-stage low noise amplifier and a 4-stage amplifier and designed, fabricated and measured at 14,0~14.5GHz of receiving frequency band. This fabricated LNA has shown the gain with very good flatness within pass-band, and its gain decreases rapidly out of band resulting in supperssion of the transmitting signal power leakage. It has shown the 20.3dB +- 0.1dB of pass-band gain, the 1.44dB +-0.04dB of noise figure and the 14dB rejection out of band(12.25~12.75GHz). The gain flatness, noise figure and group delay of this 2-stage LNA satisfactorily met the simulation results. And the fabricated 4-stage amplifier has shown the more than 42dB of pass-band gain, the +-0.25dB of flatness and the 28dB of the rejection effect for transmitting power leakage. The 2-stage LNA and 4-stage amplifier, in this paper, will bring a design margin for the input filter and also result in the system cost reduction.

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Sintering and Dielectric Properties of K2O-CaO-P2O5 Glasses-BNT(BaO-Nd2O3-TiO2) Ceramic Composites (K2O-CaO-P2O5계 유리-BNT(BaO-Nd2O3-TiO2)계 세라믹 복합체의 소결 및 유전특성)

  • 오영석;이용수;강원호;정병해;김형순
    • Journal of the Korean Ceramic Society
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    • v.40 no.10
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    • pp.954-960
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    • 2003
  • To develop mobile phone antenna modules, glass-ceramics composites that are 20∼80 dielectric constant materials which has been fabricated. The glass-ceramics composites were based in the BNT (BaO-Nd$_2$O$_3$-TiO$_2$), and properties-a sintering and dielectric property-were investigated in its composites according to the $K_2$O-CaO-P$_2$O$_{5}$ system glass frits. The prepared ceramics were sintered at 900∼120$0^{\circ}C$ with the glass frit contents ranging from 10 to 40 wt%. The shrinkage and relative density grew into increasing glass frits and sintering temperature. Sintered composites showed the tendency that the dielectric constant ($\varepsilon$$_{r}$) and quality factor (Q${\times}$f) decreased in increasing glass frits and sintering temperature.

Performance Analysis of MVDR and RLS Beamforming Using Systolic Array Structure (시스토릭 어레이 구조를 갖는 최소분산 비왜곡응답 및 최소자승 회귀 빔형성기법 성능 분석)

  • 이호중;서상우;이원철
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.1
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    • pp.1-6
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    • 2003
  • This paper analyses the performance of either the minimum variance distortionless response (MVDR) or the recursive least square (RLS) beamformer structured on the systolic array. Provided that the snapshot vector including the desired user's signal and the interferences with the noise is received at the array antenna. In order to improve the quality of received signal, MVDR or RLS algorithm can be utilized to update the beamformer weights recursively. Furthermore to increase the channel capacity, by the usage of the above schemes, the effect of the spatial filtering can be obtained which constructively combining multipath components corresponding to the desired user whereas the multiple access interferences (MAI) is nulled out on spatial domain. This paper introduces the MVDR and RLS beamformer structured on systolic array conducting the spatial filtering, and its performance under the multipath fading channel in the presence of multiple access interferences will be analyzed. To show the superior spatial filtering performances of the proposed scheme employing the systolic way structured beamformer, the computer simulations are carried out. And the validity of practical deployment of the proposed scheme will be confirmed throughout showing the BER behaviors and the beampatterns.

The Future of Radio and its Role in the Era of Smart Media (스마트미디어 시대 속 라디오의 미래와 역할 고찰)

  • KWON, Youngsung;SONG, Haeryong
    • Trans-
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    • v.1
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    • pp.117-139
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    • 2016
  • Radio, the first broadcasting medium in history, is also the first mobile medium that meets the currently mobile ecology based on mobile communications network. As a result, it is easily approachable to consumers, can easily engage individual consumers, and its program contents have a huge appealing power to individual listeners, allowing it to form intimacy with audiences at the closest distance. However, the listening rating of radio has decreased greatly because it has experienced various changes by many other competitive media such as TV and internet and it has been influenced by relative constant hypothesis. Also, radio now faces a bigger competition due to the emergence of smartphone. In this circumstance, radio showed movements to evolve into a digital radio that presents improved sound, strengthened reception power, and increased number of channels, but it suddenly changed to DMB and portable multimedia DMB is having huge problems in its marketability due to smartphone. Yet, the listening rating of analogue radio broadcasting that remained unchanged was 13.99% in 2014, an increase by 47% from 2011, and the percentage of listeners under the age of 18 increased by 2.4 times from 2011 to 2014, which was a unique and interesting phenomenon. Accordingly, this paper compared the characteristics of internet and radio that have the traits of daily life, information, individuality, participatory, adventurousness, alternative media, expertise, and sound media. The paper then examined the listening method of radio, in which the direct groundwave antenna reception through a vehicular device is the most common form during the use of transportation means. Finally, it sought to investigate the future of radio based on the understanding of the increase in radio listening ratings, especially by comparing it to the characteristics of smart generation that focus on smartphone and the internet The study results demonstrated that entertainment and amusements are attempting at changes while they used to be obtained selectively by the smart generation from fragmentary information. In addition, radio is expected to become an influential medium in the future through its advantages of 'selected information' and reliability. However, considering such possibilities, radio needs to build the expertise and reliability of broadcasting contents much more at the same time as its digitalization, and it will be able to have its own competitiveness by focusing on various experiences and cultural exposures.

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A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND B-MODE POLARIZATION WITH POLARBEAR

  • ADE, P.A.R.;AKIBA, Y.;ANTHONY, A.E.;ARNOLD, K.;ATLAS, M.;BARRON, D.;BOETTGER, D.;BORRILL, J.;CHAPMAN, S.;CHINONE, Y.;DOBBS, M.;ELLEFLOT, T.;ERRARD, J.;FABBIAN, G.;FENG, C.;FLANIGAN, D.;GILBERT, A.;GRAINGER, W.;HALVERSON, N.W.;HASEGAWA, M.;HATTORI, K.;HAZUMI, M.;HOLZAPFEL, W.L.;HORI, Y.;HOWARD, J.;HYLAND, P.;INOUE, Y.;JAEHNIG, G.C.;JAFFE, A.H.;KEATING, B.;KERMISH, Z.;KESKITALO, R.;KISNER, T.;JEUNE, M. LE;LEE, A.T.;LEITCH, E.M.;LINDER, E.;LUNGU, M.;MATSUDA, F.;MATSUMURA, T.;MENG, X.;MILLER, N.J.;MORII, H.;MOYERMAN, S.;MYERS, M.J.;NAVAROLI, M.;NISHINO, H.;ORLANDO, A.;PAAR, H.;PELOTON, J.;POLETTI, D.;QUEALY, E.;REBEIZ, G.
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.625-628
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    • 2015
  • POLARBEAR is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic inflation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1.274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.

Freshwater Fish Utilization of Fishway Installed in the Jangheung Dam (장흥댐에 설치되어 있는 어도와 담수어류의 이용 분석)

  • Yoon, Ju-Duk;Kim, Jeong-Hui;Joo, Gea-Jae;Seo, Jin-Won;Pak, Hubert;Jang, Min-Ho
    • Korean Journal of Ecology and Environment
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    • v.44 no.3
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    • pp.264-271
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    • 2011
  • At the Jangheung multipurpose dam, which is on the Tamjin River, a trapping and trucking operation was established to maintain continuous upstream migration of fish,. To facilitate fish gathering, installation of an effective fishing trap was required. In this study, we evaluated the fish trap, established at the Jangheung dam, using PIT (Passive Integrated Transponder) telemetry. A total of 254 individuals from 15 species were monitored. Among these tagged species, 36 individuals from 6 species (Carassius auratus, C. cuvieri, Zacco temminckii, Z. platypus, Pungtungia herzi, and Pseudobagrus koreanus) were detected; a 14.2% detection rate. C. auratus recorded the highest detection rate of 44.2% while P. herzi was 14.3%. Z. temminckii and Z. platypus showed relatively low detection, 5% and 7.7% respectively. Some of individuals from C. auratus and Z. platypus did not pass through the antenna at the first attempt but were continuously detected on multiple days. There were no statistical differences in body size (total length, standard length and body weight) of individuals that did or did not swim into the trap (Mann-Whitney U test, p>0.05). Fish mainly swam into the trap during outflow of water from the dam (Mann-Whitney U test, p<0.001) and showed a higher detection frequency in daytime than nighttime (Mann-Whitney U test, p<0.001). Thus, for fish movement into the trap, external factors such as outflow from dam and time of day have important roles. Based on detection rate, not all fishes showed upstream migration but represented selective migration. Consequently, the establishment of flexible outflow strategies that take into consideration ecological characteristics of fishes should required for improving the efficiency of fishway.

Mapping Precise Two-dimensional Surface Deformation on Kilauea Volcano, Hawaii using ALOS2 PALSAR2 Spotlight SAR Interferometry (ALOS-2 PALSAR-2 Spotlight 영상의 위성레이더 간섭기법을 활용한 킬라우에아 화산의 정밀 2차원 지표변위 매핑)

  • Hong, Seong-Jae;Baek, Won-Kyung;Jung, Hyung-Sup
    • Korean Journal of Remote Sensing
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    • v.35 no.6_3
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    • pp.1235-1249
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    • 2019
  • Kilauea Volcano is one of the most active volcano in the world. In this study, we used the ALOS-2 PALSAR-2 satellite imagery to measure the surface deformation occurring near the summit of the Kilauea volcano from 2015 to 2017. In order to measure two-dimensional surface deformation, interferometric synthetic aperture radar (InSAR) and multiple aperture SAR interferometry (MAI) methods were performed using two interferometric pairs. To improve the precision of 2D measurement, we compared root-mean-squared deviation (RMSD) of the difference of measurement value as we change the effective antenna length and normalized squint value, which are factors that can affect the measurement performance of the MAI method. Through the compare, the values of the factors, which can measure deformation most precisely, were selected. After select optimal values of the factors, the RMSD values of the difference of the MAI measurement were decreased from 4.07 cm to 2.05 cm. In each interferograms, the maximum deformation in line-of-sight direction is -28.6 cm and -27.3 cm, respectively, and the maximum deformation in the along-track direction is 20.2 cm and 20.8 cm, in the opposite direction is -24.9 cm and -24.3 cm, respectively. After stacking the two interferograms, two-dimensional surface deformation mapping was performed, and a maximum surface deformation of approximately 30.4 cm was measured in the northwest direction. In addition, large deformation of more than 20 cm were measured in all directions. The measurement results show that the risk of eruption activity is increasing in Kilauea Volcano. The measurements of the surface deformation of Kilauea volcano from 2015 to 2017 are expected to be helpful for the study of the eruption activity of Kilauea volcano in the future.

Three dimensional GPR survey for the exploration of old remains at Buyeo area (부여지역 유적지 발굴을 위한 3차원 GPR 탐사)

  • Kim Jung-Bo;Son Jeong-Sul;Yi Myeong-Jong;Lim Seong-Keun;Cho Seong-Jun;Jeong Ji-Min;Park Sam-Gyu
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.49-69
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    • 2004
  • One of the important roles of geophysical exploration in archeological survey may be to provide the subsurface information for effective and systematic excavations of historical remains. Ground Penetrating Radar (GPA) can give us images of shallow subsurface structure with high resolution and is regarded as a useful and important technology in archeological exploration. Since the buried cultural relics are the three-dimensional (3-D) objects in nature, the 3-D or areal survey is more desirable in archeological exploration. 3-D GPR survey based on the very dense data in principle, however, might need much higher cost and longer time of exploration than the other geophysical methods, thus it could have not been applied to the wide area exploration as one of routine procedures. Therefore, it is important to develop an effective way of 3-D GPR survey. In this study, we applied 3-D GPR method to investigate the possible historical remains of Baekje Kingdom at Gatap-Ri, Buyeo city, prior to the excavation. The principal purpose of the investigation was to provide the subsurface images of high resolution for the excavation of the surveyed area. Besides this, another purpose was to investigate the applicability and effectiveness of the continuous data acquisition system which was newly devised for the archeological investigation. The system consists of two sets of GPR antennas and the precise measurement device tracking the path of GPR antenna movement automatically and continuously Besides this hardware system, we adopted a concept of data acquisition that the data were acquired arbitrary not along the pre-established profile lines, because establishing the many profile lines itself would make the field work much longer, which results in the higher cost of field work. Owing to the newly devised system, we could acquire 3-D GPR data of an wide area over about $17,000 m^2$ as a result of the just two-days field work. Although the 3-D GPR data were gathered randomly not along the pre-established profile lines, we could have the 3-D images with high resolution showing many distinctive anomalies which could be interpreted as old agricultural lands, waterways, and artificial structures or remains. This case history led us to the conclusion that 3-D GPR method can be used easily not only to examine a small anomalous area but also to investigate the wider region of archeological interests. We expect that the 3-D GPR method will be applied as a one of standard exploration procedures to the exploration of historical remains in Korea in the near future.

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Effective 3-D GPR Survey for the Exploration of Old Remains (유적지 발굴을 위한 효율적 3차원 GPR 탐사)

  • Kim, Jung-Ho;Yi, Myeong-Jong;Son, Jeong-Sul;Cho, Seong-Jun;Park, Sam-Gyu
    • Geophysics and Geophysical Exploration
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    • v.8 no.4
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    • pp.262-269
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    • 2005
  • Since the buried cultural relics are three-dimensional (3-D) objects in nature, 3-D survey is more preferable in archeological exploration. 3-D Ground Penetrating Radar (GPR) survey based on very dense data in principle, however, might need much higher cost and longer time of exploration than other geophysical methods commonly used for the archeological exploration, such as magnetic and electromagnetic methods. We developed a small-scale continuous data acquisition system which consists of two sets of GPR antennas and the precise positioning device tracking the moving-path of GPR antenna automatically and continuously. Since the high cost of field work may be partly attributed to establishing many profile lines, we adopted a concept of data acquisition at arbitrary locations not along the pre-established profile lines. Besides this hardware system, we also developed several software packages in order to effectively process and visualize the 3-D data obtained by the developed system and the data acquisition concept. Using the developed system, we performed 3-D GPR survey to investigate the possible historical remains of Baekje Kingdom at Buyeo city, South Korea, prior to the excavation. Owing to the newly devised system, we could obtain 3-D GPR data of this survey area having areal extent over about $17,000m^2$ within only six-hours field work. Although the GPR data were obtained at random locations not along the pre-established profile lines, we could obtain high-resolution 3-D images showing many distinctive anomalies, which could be interpreted as old agricultural lands, waterways, and artificial structures or remains. This cast: history led us to the conclusion that 3-D GPR method is very useful not only to examine a small anomalous area but also to investigate the wider region of the archeological interests.