• Title/Summary/Keyword: Differential processing

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An Efficient Scheme to Achieve Differential Unitary Space-Time Modulation on MIMO-OFDM Systems

  • Liu, Shou-Yin;Chong, Jong-Wha
    • ETRI Journal
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    • v.26 no.6
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    • pp.565-574
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    • 2004
  • Differential unitary space-time modulation (DUSTM) has emerged as a promising technique to obtain spatial diversity without intractable channel estimation. This paper presents a study of the application of DUSTM on multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems with frequency-selective fading channels. From the view of a correlation analysis between subcarriers of OFDM, we obtain the maximum achievable diversity of DUSTM on MIMO-OFDM systems. Moreover, an efficient implementation strategy based on subcarrier reconstruction is proposed, which transmits all the signals of one signal matrix in one OFDM transmission and performs differential processing between two adjacent OFDM blocks. The proposed method is capable of obtaining both spatial and multipath diversity while reducing the effect of time variation of channels to a minimum. The performance improvement is confirmed by simulation results.

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Development of the SAR Data Processing Package

  • Kim Kwang-Yong;Jeong Soo;Kim Kyoung-Ok
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.526-528
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    • 2004
  • This paper describes the SAR data processing S/W package it will be able to process the SAR image. This package constructs the several modules: SAR Image processing module, measuring module of surface displacement using differential interferometric SAR method, classification module using the POLSAR data, SAR Focusing module. In this paper, briefly describe the algorithm that is adopted to the functions, and module architecture.

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The direct digital frequency synthesizer of QD-ROM reduction using the differential quantization (차동 양자화를 사용한 QD-ROM 압축 방식의 직접 디지털 주파수 합성기)

  • Kim, Chong-Il;Lim, So-Young;Lee, Ho-Jin
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.3
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    • pp.192-198
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    • 2007
  • In this paper, a new method to reduce the size of ROM in the direct digital frequency synthesizer(DDFS) is proposed. The new ROM compression method can reduce the ROM size by using the two ROM. The quantized value of sine is stored by the quantized-ROM(Q-ROM) and the differential ROM(D-ROM). To reduce the ROM size, we use the differential quantization technique with this two ROM. First, we quantize the quarter sine wave with the $2^L$ address and store the quantized value at the Q-ROM. Second, after the $2^L$ address are equally divided into $2^M$ sampling intervals, the sampling value is quantized. And the D-ROM store only the difference between this quantized value and the Q-ROM. So the total size of the ROM in the proposed DDFS is significantly reduced compared to the original ROM. The ROM compression ratio of 67.5% is achieved by this method. Also, the power consumption is affected mostly by this ROM reduction.

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Achieving Relative Loss Differentiation using D-VQSDDP with Differential Drop Probability (차별적이니 드랍-확률을 갖는 동적-VQSDDP를 이용한 상대적 손실차별화의 달성)

  • Kyung-Rae Cho;Ja-Whan Koo;Jin-Wook Chung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.1332-1335
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    • 2008
  • In order to various service types of real time and non-real time traffic with varying requirements are transmitted over the IEEE 802.16 standard is expected to provide quality of service(QoS) researchers have explored to provide a queue management scheme with differentiated loss guarantees for the future Internet. The sides of a packet drop rate, an each class to differential drop probability on achieving a low delay and high traffic intensity. Improved a queue management scheme to be enhanced to offer a drop probability is desired necessarily. This paper considers multiple random early detection with differential drop probability which is a slightly modified version of the Multiple-RED(Random Early Detection) model, to get the performance of the best suited, we analyzes its main control parameters (maxth, minth, maxp) for achieving the proportional loss differentiation (PLD) model, and gives their setting guidance from the analytic approach. we propose Dynamic-multiple queue management scheme based on differential drop probability, called Dynamic-VQSDDP(Variable Queue State Differential Drop Probability)T, is proposed to overcome M-RED's shortcoming as well as supports static maxp parameter setting values for relative and each class proportional loss differentiation. M-RED is static according to the situation of the network traffic, Network environment is very dynamic situation. Therefore maxp parameter values needs to modify too to the constantly and dynamic. The verification of the guidance is shown with figuring out loss probability using a proposed algorithm under dynamic offered load and is also selection problem of optimal values of parameters for high traffic intensity and show that Dynamic-VQSDDP has the better performance in terms of packet drop rate. We also demonstrated using an ns-2 network simulation.

Design of Heavy Rain Advisory Decision Model Based on Optimized RBFNNs Using KLAPS Reanalysis Data (KLAPS 재분석 자료를 이용한 진화최적화 RBFNNs 기반 호우특보 판별 모델 설계)

  • Kim, Hyun-Myung;Oh, Sung-Kwun;Lee, Yong-Hee
    • Journal of the Korean Institute of Intelligent Systems
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    • v.23 no.5
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    • pp.473-478
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    • 2013
  • In this paper, we develop the Heavy Rain Advisory Decision Model based on intelligent neuro-fuzzy algorithm RBFNNs by using KLAPS(Korea Local Analysis and Prediction System) Reanalysis data. the prediction ability of existing heavy rainfall forecasting systems is usually affected by the processing techniques of meteorological data. In this study, we introduce the heavy rain forecast method using the pre-processing techniques of meteorological data are in order to improve these drawbacks of conventional system. The pre-processing techniques of meteorological data are designed by using point conversion, cumulative precipitation generation, time series data processing and heavy rain warning extraction methods based on KLAPS data. Finally, the proposed system forecasts cumulative rainfall for six hours after future t(t=1,2,3) hours and offers information to determine heavy rain advisory. The essential parameters of the proposed model such as polynomial order, the number of rules, and fuzzification coefficient are optimized by means of Differential Evolution.

Bidirectional Power Conversion of Isolated Switched-Capacitor Topology for Photovoltaic Differential Power Processors

  • Kim, Hyun-Woo;Park, Joung-Hu;Jeon, Hee-Jong
    • Journal of Power Electronics
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    • v.16 no.5
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    • pp.1629-1638
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    • 2016
  • Differential power processing (DPP) systems are among the most effective architectures for photovoltaic (PV) power systems because they are highly efficient as a result of their distributed local maximum power point tracking ability, which allows the fractional processing of the total generated power. However, DPP systems require a high-efficiency, high step-up/down bidirectional converter with broad operating ranges and galvanic isolation. This study proposes a single, magnetic, high-efficiency, high step-up/down bidirectional DC-DC converter. The proposed converter is composed of a bidirectional flyback and a bidirectional isolated switched-capacitor cell, which are competitively cheap. The output terminals of the flyback converter and switched-capacitor cell are connected in series to obtain the voltage step-up. In the reverse power flow, the converter reciprocally operates with high efficiency across a broad operating range because it uses hard switching instead of soft switching. The proposed topology achieves a genuine on-off interleaved energy transfer at the transformer core and windings, thus providing an excellent utilization ratio. The dynamic characteristics of the converter are analyzed for the controller design. Finally, a 240 W hardware prototype is constructed to demonstrate the operation of the bidirectional converter under a current feedback control loop. To improve the efficiency of a PV system, the maximum power point tracking method is applied to the proposed converter.

Sliding Multiple Phase Differential Detection of Trellis-coded MDPSK-OFDM (흐름 다중 심벌 검파를 사용한 트렐리스 부호화된 MDPSK-OFDM)

  • 김종일
    • Journal of the Institute of Convergence Signal Processing
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    • v.3 no.2
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    • pp.37-44
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    • 2002
  • In this paper, the Viterbi decoder containing new branch metrics of the squared Euclidean distance with multiple order phase differences is introduced in order to improve the bit error rate (BER) in the differential detection of the trellis-coded MDPSK-DFDM. The proposed Viterbi decoder is conceptually same as the sliding multiple phase differential detection method that uses the branch metric with multiple phase differences. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbi decoder improves BER peformance without sacrificing bandwidth and power efficiency. Also, the proposed algorithm can be used in the single carrier modulation.

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Design methodology of analog circuits for a digital-audio-signal processing 1-bit ???? DAC (디지털 오디오 신호처리용 1-bit Δ$\Sigma$ DAC 아날로그 단의 설계기법)

  • 이지행;김상호;손영철;김선호;김대정;김동명
    • Proceedings of the IEEK Conference
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    • 2002.06b
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    • pp.149-152
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    • 2002
  • The performance of a 1-bit DAC depends on that of the analog circuits. The mixed SC-CT (switched capacitor-continuous time) architecture is an effective design methodology for the analog circuits. This paper Proposes a new buffer scheme for the 1-bit digital-to-analog subconverter and a new SF-DSC(smoothing filter and differential-to-sig le converter) which performs both the smoothing filter and the differential-to-single convertor simultaneously.

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A Study of Low-Voltage Low-Power Linear Transconductor (저전압 저전력 선형 트랜스컨덕터에 관한 연구)

  • 김동용;신희종;차형우;정원섭
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.967-970
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    • 1999
  • A novel linear transconductor for low-voltage low-power signal processing is proposed. The transconductor consists of a pnp differential-pair and a npn differential-pair which are biased by local negative feedback. The simulation results show that the transcondcutor with transconductance of 50 $mutextrm{s}$ has a linearity error of 0.05% and the power dissipation is 2.44 ㎽ over an input linear range from -2V to +2V at supply voltage $\pm$3V.

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