• Title/Summary/Keyword: Channel Switching

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Traffic Characterization and Analysis for AO/DI Internet Services (AO/DI 인터넷 서비스 도입을 위한 트랙픽 분석 연구)

  • 이강원;국광호;정광재;김태일
    • Journal of the Korean Operations Research and Management Science Society
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    • v.25 no.3
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    • pp.65-79
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    • 2000
  • Based on the results of the internet service survey, the traffic demand forecasts of the AO/DI internet service and N-ISDN service have been performed for each channel(B-channel and D-channel). These traffic forecasts can be used as useful input data for investigating packet processing capacity of the TDX-10A switching system and suggesting guideline for capacity increasement.

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A Model of GaAs MESFET with Channel Length Modulation (채널길이 변화를 이용한 GaAs MESFET의 모델)

  • 임재완;윤현로;이기준
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.4
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    • pp.547-554
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    • 1990
  • Considering channel length modulation, we proposed a GaAs MESFET model for circuit simulator. In existing M.S. Shur's model, two different models are used according to pinch-off voltage of devices. One model for both type of devices was proposed. In this model we introduced weighted switching function(WSF) based on channel length modulation. This proposed model showed better accuracy comparing with existing single law model and complete velocity saturation model.

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Application of the Beam Propagation Method to the analysis of Dual-channel directional couplers (Dual-channel directional couplers 동작특성 해석을 위한 BPM의 적용)

  • Kang, Kyung-Woo;Kang, Hyung-Boo
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.660-662
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    • 1993
  • We have numerically analyzed by using the Beam Propagation Method the Dual-channel directional couplers, which peforms a number of useful fuctions in thin-films devices, including power division, modulation, switching, frequency selection, and polarization selection. We also use the effective index method to reduce one dimension.

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Theoretical Analysis of MIMO Antenna Selection & Switching System to Spatial Channel Correlation using Channel Statistics (공간적 채널 상관도에 따른 통계적인 채널 특성을 이용한 다중 안테나 선택 및 스위칭 시스템의 성능 분석)

  • Lee Hakju;Park Seungil;Lee Chungyong;Park Hyuncheol;Hong Daesik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.4 s.334
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    • pp.15-20
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    • 2005
  • Multi-Input, Multi-Output system suffers for the spatial channel correlation due to lack of spatial diversity. To overcome this defect, the antenna selection and switching system is proposed which selects the adequate antenna subset with highest channel diversity gain and switches the trasmission techniques according to channel environments. However. its performance analysis is insufficient due to the difficulty of modeling the spatial channel correlation. In this paper, the theoretical upper bound of symbol error probability is derived by using the statistical properties of Frobenius norm and minimum eigen-value of channel matrix. By computer simulation, it is shown that the derived theoretical upper bound is similar to the simulation results.

Cluster-based Minimum Interference Channel Assignment for Multi-Radio Multi-Channel Wireless Mesh Networks (멀티 라디오 멀티 채널 무선 메쉬 네트워크를 위한 클러스터 기반 최소 간섭 채널 할당)

  • Cha, Si Ho;Ryu, Min Woo;Cho, Kuk Hyun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.3
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    • pp.103-109
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    • 2010
  • Total performance is improved by minimizing the channel interference between links in wireless mesh networks (WMNs). The paper refines on the CB-CA [1] to be suitable for multi-radio multi-channel (MRMC) WMNs. The CB-CA is the cluster-based channel assignment algorithm for one radio three channel WMN based on IEEE 802.11b/g. The CB-CA does not perform the channel scanning and the channel switching between the cluster heads (CHs) and the edge gateway nodes (EGs). However, the use of co-channel for links between CHs and EGs brings the problem of channel interference among many nodes. We propose and evaluate an improved CB-CA algorithm to solve this problem in MRMC WMNs. The proposed algorithm discriminates between transmission channel and receive channel and assigns channels to each interface randomly and advertises this information to neighbor clusters in order to be assigned no-interference channel between clusters. Therefore, the proposed algorithm can minimize the interference between clusters and also improve QoS, since it can use multiple interfaces and multiple channels.

Minimum Bandwidth Guarantee for Optical Burst Switching Networks (광 버스트 스위칭망에서 최소 대역폭 보장)

  • 오승훈;김영한
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.10
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    • pp.59-66
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    • 2003
  • We propose the novel optical burst switching scheme to guarantee a minimum bandwidth for multiple classes. To date, QoS studies on OBS network are capable of differentiating two classes, but have difficulties in providing a minimum bandwidth lot several classes because of lower classes' collision with the highest class bursts in the networks. To solve that problem, in our proposed scheme we assign time zones in a data channel for each class periodically, making one burst have top priority at least its zone. Also, the new burst assembling algorithm, as well as the way of managing data channel, is necessarily proposed to coordinate with the proposed OBS scheme. Through the evaluation, we show that the worst-case end-to-end delay is small enough and the received bandwidth of the lower classes is still assured regardless of the traffic load of the highest class.

Joint Blind Parameter Estimation of Non-cooperative High-Order Modulated PCMA Signals

  • Guo, Yiming;Peng, Hua;Fu, Jun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.10
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    • pp.4873-4888
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    • 2018
  • A joint blind parameter estimation algorithm based on minimum channel stability function aimed at the non-cooperative high-order modulated paired carrier multiple access (PCMA) signals is proposed. The method, which uses hierarchical search to estimate time delay, amplitude and frequency offset and the estimation of phase offset, including finite ambiguity, is presented simultaneously based on the derivation of the channel stability function. In this work, the structure of hierarchical iterative processing is used to enhance the performance of the algorithm, and the improved algorithm is used to reduce complexity. Compared with existing data-aided algorithms, this algorithm does not require a priori information. Therefore, it has significant advantage in solving the problem of blind parameter estimation of non-cooperative high-order modulated PCMA signals. Simulation results show the performance of the proposed algorithm is similar to the modified Cramer-Rao bound (MCRB) when the signal-to-noise ratio is larger than 16 dB. The simulation results also verify the practicality of the proposed algorithm.

The Cash Flow Sensitivity of Investment: A Switching Regression Approach Based on Korean Firm Data (기업투자의 현금흐름 민감도: 전환회귀법을 이용한 분석)

  • Koo, Jaewoon;Maeng, Kyunghee
    • Economic Analysis
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    • v.17 no.2
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    • pp.56-89
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    • 2011
  • The sensitivity of investment with respect to cash flow is positive in imperfect financial markets. Using a switching regression model, cash flow sensitivity of investments in chaebol firms and large firms appears to be higher. Also, investments are found to be more responsive to cash flow during monetary contraction periods. These findings imply that monetary policy works through a credit channel. Furthermore, it appears that monetary policy exerts distributional effects as well as aggregate effects on that firms are unevenly affected by monetary changes.

Channel and Gate Workfunction-Engineered CNTFETs for Low-Power and High-Speed Logic and Memory Applications

  • Wang, Wei;Xu, Hongsong;Huang, Zhicheng;Zhang, Lu;Wang, Huan;Jiang, Sitao;Xu, Min;Gao, Jian
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.1
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    • pp.91-105
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    • 2016
  • Carbon Nanotube Field-Effect Transistors (CNTFETs) have been studied as candidates for post Si CMOS owing to the better electrostatic control and high mobility. To enhance the immunity against short - channel effects (SCEs), the novel channel and gate engineered architectures have been proposed to improve CNTFETs performance. This work presents a comprehensive study of the influence of channel and gate engineering on the CNTFET switching, high frequency and circuit level performance of carbon nanotube field-effect transistors (CNTFETs). At device level, the effects of channel and gate engineering on the switching and high frequency characteristics for CNTFET have been theoretically investigated by using a quantum kinetic model. This model is based on two-dimensional non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. It is revealed that hetero - material - gate and lightly doped drain and source CNTFET (HMG - LDDS - CNTFET) structure can significantly reduce leakage current, enhance control ability of the gate on channel, improve the switching speed, and is more suitable for use in low power, high frequency circuits. At circuit level, using the HSPICE with look - up table(LUT) based Verilog - A models, the impact of the channel and gate engineering on basic digital circuits (inverter, static random access memory cell) have been investigated systematically. The performance parameters of circuits have been calculated and the optimum metal gate workfunction combinations of ${\Phi}_{M1}/{\Phi}_{M2}$ have been concluded in terms of power consumption, average delay, stability, energy consumption and power - delay product (PDP). In addition, we discuss and compare the CNTFET-based circuit designs of various logic gates, including ternary and binary logic. Simulation results indicate that LDDS - HMG - CNTFET circuits with ternary logic gate design have significantly better performance in comparison with other structures.

Multi-Tag Beamforming Scheme Based on Backscatter Communication for RF Energy Harvesting Networks (RF 에너지 하베스팅 네트워크를 위한 Backscatter 통신 기반의 다중 태그 빔포밍 기법)

  • Hong, Seung Gwan;Hwang, Yu Min;Lee, Sun Yui;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.11 no.2
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    • pp.60-64
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    • 2016
  • In this paper, we propose a scheme for MIMO beamforming for the backscatter communication using a multi-tag to improve the efficiency of energy harvesting and the BER of received signals. We obtain a normal channel information through a communication between the H-AP and multi-tag. The H-AP sets parameters for the transmission scenario of the spatial channel model (SCM) using the obtained channel information and generates a SCM channel information. Then, the H-AP transmits signals that have optimal transmission power to increase the signal-to-interference-plus-noise ratio (SINR) to each of tags. Tags perform a backscatter communication with signals. The receiver performs a time switching technique of energy harvesting using backscatter signals from the multi-tag. Simulation results demonstrate effectiveness of the proposed scheme, and the harvesting efficiency and BER at the receiver is greatly improved.