• Title/Summary/Keyword: AM Transmitter

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Anti-Jamming and Time Delay Performance Analysis of Future SATURN Upgraded Military Aerial Communication Tactical Systems

  • Yang, Taeho;Lee, Kwangyull;Han, Chulhee;An, Kyeongsoo;Jang, Indong;Ahn, Seungbeom
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.9
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    • pp.3029-3042
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    • 2022
  • For over half a century, the United States (US) and its coalition military aircrafts have been using Ultra High Frequency (UHF) band analog modulation (AM) radios in ground-to-air communication and short-range air-to-air communications. Evolving from this, since 2007, the US military and the North Atlantic Treaty Organization (NATO) adopted HAVE QUICK to be used by almost all aircrafts, because it had been revealed that intercepting and jamming of former aircraft communication signals was possible, which placed a serious threat to defense systems. The second-generation Anti-jam Tactical UHF Radio for NATO (SATURN) was developed to replace HAVE QUICK systems by 2023. The NATO Standardization Agreement (STANAG) 4372 is a classified document that defines the SATURN technical and operational specifications. In preparation of this future upgrade to SATURN systems, in this paper, the SATURN technical and operational specifications are reviewed, and the network synchronization, frequency hopping, and communication setup parameters that are controlled by the Network (NET) Time, Time Of Day (TOD), Word Of Day (WOD), and Multiple Word of Day (MWOD) are described in addition to SATURN Edition 3 (ED3) and future Edition 4 (ED4) basic features. In addition, an anti-jamming performance analysis (in reference to partial band jamming and pulse jamming) and the time delay queueing model analysis are conducted based on a SATURN transmitter and receiver assumed model.

Adaptive Modulation System Using SNR Estimation Method Based on Correlation of Decision Feedback Signal (Decision Feedback 신호의 자기 상관 기반 SNR 추정 방법을 적용한 적응 변조 시스템)

  • Kim, Seon-Ae;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.3
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    • pp.282-291
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    • 2011
  • Adaptive modulation(AM) is an important technique to increase the system efficiency, in which transmitter selects the most suitable modulation mode adaptively according to channel state in the temporary and spatially varying communication environment. Fixed modulation on channels with varying signal-to-noise ratio(SNR) is that the bit-errorrate(BER) probability performance is changing with the channel quality. An adaptive modulation scheme can be designed to have a BER which is constant for all channel SNRs. The correct as well as fast and simple SNR estimation is required essentially for this adaptive modulation. In order to operate adaptive modulation system effectively, in this paper, we analyze the effect of SNR estimation performance to it through the average BER and data throughput. Applying SNR estimation based on auto-correlation of decision feedback signal and others to adaptive modulation system, we also confirm performance degradation or improvement of its which is decided by SNR estimation error at each transition point of modulation level. Since SNR estimation based on auto-correlation of decision feedback signal shows stable estimation performance for various quadrature amplitude modulation(QAM) comparatively, this can be reduced degradation than others at each transition point of modulation level.

Analysis of Body Induced Current in Middle Frequency Range Using Quasi-Static FDTD (중간주파수 대역에서 준정적(Quasi-Static) FDTD 기법을 이용한 인체 유도전류 분석)

  • Byun, Jin-Kyu
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.1
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    • pp.141-149
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    • 2009
  • In this paper, quasi-static FDTD method is implemented by FORTRAN programming, and it is used for analysis of body induced current in middle frequencies. The quasi-static FDTD program is validated by comparing the calculation result with analytic solution of the test model, to which it is difficult to apply conventional FDTD. It is confirmed that the time-step is reduced by $5.68{\times}10^6$ times. Using validated numerical technique, body induced current distribution in high resolution 3-D human model is calculated for 20[kHz] magnetic field exposure and 1[MHz] electric field exposure. Also, the effect of grounding condition of both feet on the distribution and amplitude of the induced current is analyzed. It is expected that this research can be applied to various fields including safety assessment of body induced current and development of diagnosis devices using bio-electricity.

Botulinum A toxin for the treatment of focal hyperhidrosis -5 cases- (국소화 다한증에 대해 보툴리늄 독소를 이용한 치료 -5례보고-)

  • Lee, Song-Am;Kim, Kwang-Taik;Park, Sung-Min;Chung, Bong-Kyu;Sun, Kyung;Kim, Hyoung-Mook;Lee, IIn-Sung
    • Journal of Chest Surgery
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    • v.33 no.3
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    • pp.268-272
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    • 2000
  • Thoracic sympathicotomy has been used safely and successfully to treat essential hyperhidrosis. However, it has been difficult to treat compansatory hyperhidrosis after thoracic sympathicotomy and focal hyperhidrosis. The sweat glands were innervated by post-ganglionic sympathetic fibers with acetylcholic serving as the transmitter. Botulinum A toxin has been reported to block neuro-transmission at the cholinergic autonomic nerve terminals. Prospecting its effect for the sweat gland, we treated 5 patients with focal hyperhidrosis with botulinum A toxin. Three patients received bilateral thoracic sympathectomy (1 case) and sympathicotomy(2 case) via VAT. The hyperhidrosis area was marked with betadine and was subdivided into squares of 2$\times$2 cm(4$\textrm{cm}^2$) each. Botulinum A toxin was injected intracutaneously in a dosage of 2.5U/0.1ml(100U/4ml) /4$\textrm{cm}^2$. A total dose of 100U of Botulinum A toxin was injected into the affected sites. Subjective assessment of sweat production by the patients using a visual analogue scale showed a 20~70% improvement. During the follow-up period, no toxic effects were observed.

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Korea Red Ginseng Alters Electroencephalogram Spectra of Sleep-Wake Stage in Rats

  • Ma, Yuan;Eun, Jae-Soon;Cheong, Jae-Hoon;Rhee, Dong-Kwon;Hong, Jin-Tae;Oh, Ki-Wan
    • Journal of Ginseng Research
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    • v.32 no.3
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    • pp.220-225
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    • 2008
  • The present investigation was performed to evaluate the homeostatic regulation of sleep architecture by the ethanol extract of Korea red ginseng (KRG), since the available data were often controversial. In addition, it was also interested in whether the sleep-wake stages were differently affected by low and high doses of KRG. Each adult Wistar male rat was implanted with a transmitter for recording EEG and activity via telemetry. After one week of surgery, polygraphic signs of undisturbed sleep-wake activities were recorded for 12 h (between 9:00 am and 9:00 pm) after KRG administration. KRG (10 and 100 mg/kg) increased non-rapid eye movement (NREM) sleep as well as total sleep. The total percentages of wakefulness were decreased comparably. KRG (10 mg/kg) decreased the power density of the ${\delta}-wave$ (0.75-4.5 Hz) and increased ${\alpha}-wave$ (8.0-13.0 Hz) in the NREM and rapid eye movement (REM) sleep. KRG also decreased ${\delta}-wave$ power density in wake time. However, KRG (100 mg/kg) increased ${\delta}-wave$ and decreased ${\theta}-wave$ (5.0-9.0 Hz) power density in wake time, while showed little effect on the power density in NREM and REM sleep. In conclusion, low and high doses of KRG increase spontaneous sleep and NREM sleep and differently regulate the EEG spectra in REM and NREM sleep.