• 제목/요약/키워드: channel 4

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삼음삼양(三陰三陽) 표리(表裏) 관계(關係)의 구성원리(構成原理)에 대한 연구(硏究) (A study of the exterior and interior relation's consitutional principle on three yin three yang)

  • 김준기;최달영
    • 대한한의학회지
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    • 제16권1호통권29호
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    • pp.437-450
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    • 1995
  • In order to clear the basic concept about oriental medical physiology and pathology, We studied the theory of three yin, three yang, and it is based on the principle that yang goes forward and yin goes back. The result were summarized as follows. 1. It showed how to originate about the concept of three yin three yang. 2. It showed the logical basis concerning that the TAIYANG channels are open, the YANGMING channels are shut, the SHAOYANG channels are pivots, the TAIYIN open, SHAOYIN shut, JUEYIN pivots. 3. According to the opening, closing, pivoting principle, It explained the exterior and interior relation such as TAIYANG and SHAOYIN, YANGMING and TAIYIN, SHAOYANG and JUEYIN. 4. According to the opening, closing, pivoting principle, It showed that arteries of the twelve channels rotated in lung channel of hand-TAIYIN, the large intestine channel of hand-YANGMING, the stomach channel of foot-YANGMING, the spleen channel of foot-TAIYIN, the heart channel of hand-SHAOYIN, the small intestine channel of hand-SHAOYANG, the urinary bladder channel of foot-TAIYANG, the kidney channel of foot-SHAOYIN, the pericardium channel of hand-JUEYIN, the sanjiao(三焦) channel of hand-SHAOYANG, the gall bladder channel of foot-SHAOYANG, the liver channel of foot-JUEYIN. 5. As arteries of the twelve channels was based on the cycle, the logical criticism about Napgibup(納氣法) was shown.

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On the Impact of Channel Sensing Methods to IEEE 802.15.4 Performances under IEEE 802.11b Interference

  • Shin, Soo-Young;Park, Hong-Seong
    • Journal of Communications and Networks
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    • 제10권3호
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    • pp.301-307
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    • 2008
  • In this paper, the impact of channel sensing methods to IEEE 802.15.4 under the interference of IEEE 802.11b are analyzed. Two different channel sensing methods, energy detection and carrier sense, are considered. An average transmission delay, a throughput, and a power drain rate are used as performance measures. Those performance measures of IEEE 802.15.4 under the interference of IEEE 802.11b are analyzed mathematically. The simulation results are shown to validate the analytic results.

Low-Sampling Rate UWB Channel Characterization and Synchronization

  • Maravic, Irena;Kusuma, Julius;Vetterli, Martin
    • Journal of Communications and Networks
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    • 제5권4호
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    • pp.319-327
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    • 2003
  • We consider the problem of low-sampling rate high-resolution channel estimation and timing for digital ultrawideband (UWB) receivers. We extend some of our recent results in sampling of certain classes of parametric non-bandlimited signals and develop a frequency domain method for channel estimation and synchronization in ultra-wideband systems, which uses sub-Nyquist uniform sampling and well-studied computational procedures. In particular, the proposed method can be used for identification of more realistic channel models, where different propagation paths undergo different frequency-selective fading. Moreover, we show that it is possible to obtain high-resolution estimates of all relevant channel parameters by sampling a received signal below the traditional Nyquist rate. Our approach leads to faster acquisition compared to current digital solutions, allows for slower A/D converters, and potentially reduces power consumption of digital UWB receivers significantly.

Ultra Wideband Channel Model for Indoor Environments

  • Alvarez, Alvaro;Valera, Gustavo;Manuel Lobeira;Torres, Rafael-Pedro;Garcia, Jose-Luis
    • Journal of Communications and Networks
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    • 제5권4호
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    • pp.309-318
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    • 2003
  • This paper presents an in-depth study of a UWB indoor radio channel between 1 and 9 GHz, which was used for the subsequent development of a new statistical UWB multipath channel model, focusing on short range indoor scenarios. The channel sounding process was carried out covering different indoor environments, such as laboratories, halls or corridors. A combination of new and traditional parameters has been used to accurately model the channel impulse response in order to perform a precise temporal estimation of the received pulse shape. This model is designed specifically for UWB digital systems, where the received pulse is correlated with an estimated replica of itself. The precision of the model has been verified through the comparison with measured data from equivalent scenarios and cases, and highly satisfactory results were obtained.

Xenopus Oocyte의 $K^{+}$ Channel에 관한 연구

  • 채수완
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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    • pp.160-160
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    • 1993
  • 목적: Guinea pig heart의 ATP sensitive $K^{+}$ channel xenopus oocyte에 발현시켜 연구하고져 본 실험을 행하였다. 실험방법: 기니픽 심장으로부터 ,RNA를 분리하여 50ng/$\mu$l의 농도로 50nl를 xenopusdp 주입하였다. Xenpus oocyte에서 conventional electrode를 이용 막전휘를 측정하였고, pH selective 미세전극으로 세포내 pH를 측정하였다. 막전위에 미치는 potassium channel opener, blocker, KCN의 작용을 관찰하였다. 결과: 기니픽 심장 mRNA를 주입하거나 주입하지 않은 xenopus oocyte에서 $K^{+}$channel opener인 cromakalin, RP49356등은 과분극을 일으키지 못하였다. 그러나 세포내 ATP 감소제인 KCN은 농도 의존적으로 과분극을 일으켰으나 ,glibenclamide에 의해 차단되는 않았다. mRNA를 주입한 oocyte에서 Na-H 자극제인 NH$_4$Cl은 pH 변동을 일으켜 NA-H exchange를 expression 시켰다. 결론: Xenopus oocyte는 cromakalin등에 의해 open되는 $K^{+}$channel 은 없었고, 기니픽 심근의 ATP sensitive $K^{+}$channel로 expression 되지 않았으나 Na-H exchange 는 expression 됨을 알 수 있었다. KCN으로 open 되는 $K^{+}$channel이 있었으나 glibenclamide에는 차단되지 않는 channel이였다.

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Buried Channel 다결정 실리콘 박막 트랜지스터의 설계 및 제작 (Design and Fabrication of Buried Channel Polycrystalline Silicon Thin Film Transistor)

  • 박철민;강지훈;유준석;한민구
    • 전자공학회논문지D
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    • 제35D권12호
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    • pp.53-58
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    • 1998
  • 다결정 실리콘 박막 트랜지스터를 이용한 회로의 성능 향상을 위하여 새로운 구조의 4-terminal buried channel poly-Si TFT(BCTFT)를 설계하고 제작하였다. BCTFT는 moderate 도핑이 된 buried channel을 이용하므로 기존의 다결정 실리콘 TFT보다 ON-전류와 전계 효과 이동도가 n-형과 p-형 소자 각각 5배와 10배 향상되었다. BCTFT는 moderate 도핑된 buried 채널과 counter 도핑된 body 사이의 junction 공핍에 의하여 캐리어의 이동이 억제 되므로 OFF-전류가 증가하지 않았다.

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LP-Based Blind Adaptive Channel Identification and Equalization with Phase Offset Compensation

  • Ahn, Kyung-Sseung;Baik, Heung-Ki
    • 한국통신학회논문지
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    • 제28권4C호
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    • pp.384-391
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    • 2003
  • Blind channel identification and equalization attempt to identify the communication channel and to remove the inter-symbol interference caused by a communication channel without using any known trainning sequences. In this paper, we propose a blind adaptive channel identification and equalization algorithm with phase offset compensation for single-input multiple-output (SIMO) channel. It is based on the one-step forward multichannel linear prediction error method and can be implemented by an RLS algorithm. Phase offset problem, we use a blind adaptive algorithm called the constant modulus derotator (CMD) algorithm based on condtant modulus algorithm (CMA). Moreover, unlike many known subspace (SS) methods or cross relation (CR) methods, our proposed algorithms do not require channel order estimation. Therefore, our algorithms are robust to channel order mismatch.

Twin-well 구조로 제작된 N채널 및 P채널 FET의 특성 (Characteristics of N-and P-Channel FETs Fabricated with Twin-Well Structure)

  • 김동석;이철인;서용진;김태형;김창일;장의구
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1992년도 춘계학술대회 논문집
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    • pp.86-90
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    • 1992
  • We have studied the characteristics of n-and p-channel FETs with submicron channel length fabricated by twin-well process. Threshold voltage variation and potential distribution with channel ion implantation conditions and impurity profile of n-and p-channel region wee simulated using SUPREM-II and MINIMOS 4.0 simulater, P-channel FET had buried-channel in the depth of 0.15 $\mu\textrm{m}$ from surface by counter-doped boron ion implantation for threshold voltage adjustment. As a result of device measurement, we have obtained good drain saturation characteristics for 3.3 [V] opreation, minimized short channel effect with threshold voltage shift below 0.2[V], high punchthrough and breakdown voltage above 10[V] and low subthreshold value.

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A Joint Channel Estimation and Data Detection for a MIMO Wireless Communication System via Sphere Decoding

  • Patil, Gajanan R.;Kokate, Vishwanath K.
    • Journal of Information Processing Systems
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    • 제13권4호
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    • pp.1029-1042
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    • 2017
  • A joint channel estimation and data detection technique for a multiple input multiple output (MIMO) wireless communication system is proposed. It combines the least square (LS) training based channel estimation (TBCE) scheme with sphere decoding. In this new approach, channel estimation is enhanced with the help of blind symbols, which are selected based on their correctness. The correctness is determined via sphere decoding. The performance of the new scheme is studied through simulation in terms of the bit error rate (BER). The results show that the proposed channel estimation has comparable performance and better computational complexity over the existing semi-blind channel estimation (SBCE) method.

Blind downlink channel estimation for TDD-based multiuser massive MIMO in the presence of nonlinear HPA

  • Pasangi, Parisa;Atashbar, Mahmoud;Feghhi, Mahmood Mohassel
    • ETRI Journal
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    • 제41권4호
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    • pp.426-436
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    • 2019
  • In time division duplex (TDD)-based multiuser massive multiple input multiple output (MIMO) systems, the uplink channel is estimated and the results are used in downlink for signal detection. Owing to noisy uplink channel estimation, the downlink channel should also be estimated for accurate signal detection. Therefore, recently, a blind method was developed, which assumes the use of a linear high-power amplifier (HPA) in the base station (BS). In this study, we extend this method to a scenario with a nonlinear HPA in the BS, where the Bussgang decomposition is used for HPA modeling. In the proposed method, the average power of the received signal for each user is a function of channel gain, large-scale fading, and nonlinear distortion variance. Therefore, the channel gain is estimated, which is required for signal detection. The performance of the proposed method is analyzed theoretically. The simulation results show superior performance of the proposed method compared to that of the other methods in the literature.