• Title/Summary/Keyword: AFS Technique

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An Improved Distributed Equivalent Circuit Modeling for RF Components by Real-Coefficient AFS Technique

  • Kim, Koon-Tae;Ko, Jae-Hyeong;Paek, Hyun;Kahng, Sung-Tek;Kim, Hyeong-Seok
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.408-413
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    • 2011
  • In this paper, a real-coefficient approach to Adaptive Frequency Sampling (AFS) technique is developed for efficient equivalent circuit modeling of RF components. This proposed method is advantageous than the vector fitting technique and the conventional AFS method in terms of fewer samples leading to a lower order of a rational function on a given data and to a direct conversion to an equivalent circuit for PSPICE(Personal Simulation Program with Integrated Circuit Emphsis) simulation, respectively. To validate the proposed method, the distributed equivalent circuit of a presented multi-layered RF low-pass filter is obtained using the proposed real-coefficient AFS, and then comparisons with EM simulation and circuit simulation for the device under consideration are achieved.

Optimization of Pipelined Discrete Wavelet Packet Transform Based on an Efficient Transpose Form and an Advanced Functional Sharing Technique

  • Nguyen, Hung-Ngoc;Kim, Cheol-Hong;Kim, Jong-Myon
    • Journal of Information Processing Systems
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    • v.15 no.2
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    • pp.374-385
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    • 2019
  • This paper presents an optimal implementation of a Daubechies-based pipelined discrete wavelet packet transform (DWPT) processor using finite impulse response (FIR) filter banks. The feed-forward pipelined (FFP) architecture is exploited for implementation of the DWPT on the field-programmable gate array (FPGA). The proposed DWPT is based on an efficient transpose form structure, thereby reducing its computational complexity by half of the system. Moreover, the efficiency of the design is further improved by using a canonical-signed digit-based binary expression (CSDBE) and advanced functional sharing (AFS) methods. In this work, the AFS technique is proposed to optimize the convolution of FIR filter banks for DWPT decomposition, which reduces the hardware resource utilization by not requiring any embedded digital signal processing (DSP) blocks. The proposed AFS and CSDBE-based DWPT system is embedded on the Virtex-7 FPGA board for testing. The proposed design is implemented as an intellectual property (IP) logic core that can easily be integrated into DSP systems for sub-band analysis. The achieved results conclude that the proposed method is very efficient in improving hardware resource utilization while maintaining accuracy of the result of DWPT.

Anti-islanding using Active Frequency Shake Method for Grid-connected PV Generation System (계통연계형 태양광발전시스템의 AFS 기법을 이용한 단독운전 방지)

  • Ock, Seungkyu;Kang, Moonsung;Yang, Oh
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.1
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    • pp.127-136
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    • 2013
  • The islanding detection and prevention function in the important performance of the grid-connected inverter is the essential details which should be considered for worker's safety to maintain the system. This paper tries to suggest the active frequency shake islanding detection technique in the grid-connected PV generation system using sunlight. The existing active frequency drift method algorithm is described to suggest active frequency shake method algorithm. And, the algorithm which can reduce the non-detection zone, improve THD, and improve the detection speed in comparison with the existing algorithm is suggested. And we applied the proposed algorithm to the 3kW grid-connected photovoltaic inverter generation and verified the feasibility of the technique through the simulation and experiments.

Equivalent Circuit Modeling applying Adaptive Frequency Sampling (Adaptive Frequency Sampling 을 이용한 등가회로 모델링)

  • Paek, Hyun;Kim, Koon-Tae;Kahng, Sung-Tek;Kim, Hyeong-Seok
    • 한국정보통신설비학회:학술대회논문집
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    • 2009.08a
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    • pp.281-284
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    • 2009
  • In this paper, we propose a method that applies Adaptive Frequency Sampling(AFS) technique to the equivalent circuit model for RF passive components. Thes days wireless communication system is getting smaller and smaller. So EMI/EMC is an issue in RF. We can solve PI(Power Integrity)/SI(Signal Integrity) that one of EMI/EMC problem apply IFFT for 3D EM simulation multiple with input signal. That is time comuming task. Therefore equivalent circuit model using RF passive component is important. AFS schemes are implemented to obtain the rational functions. S parameters of the equivalent circuit moldel is compared to those of EM simulation in case of the microstrip line structure.

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Anti-Fraud System for Credit Card By Using Hybrid Technique (Hybrid 기법을 적용한 효율적인 신용카드판단시스템)

  • 조문배;박길흠
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.41 no.5
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    • pp.25-32
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    • 2004
  • An anti-fraud system that utilizes association rules of fraud as well as AFS (Anti Fraud System) for credit card payments in e-commerce is proposed. The association rules are found by applying the data mining algorithm to millions of transaction records that have been generated as a result of orders on goods through the Internet. When a customer begins to process an order by using transaction components of a secure messaging protocol, the degree of risk for the transaction is assessed by using the found rules. More credit information will be requested or the transaction is rejected if it is interpreted as risky.