• Title/Summary/Keyword: 신호 최적화

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Quantization Method for Normalization of JPEG Pleno Hologram (JPEG Pleno 홀로그램 데이터의 정규화를 위한 양자화)

  • Kim, Kyung-Jin;Kim, Jin-Kyum;Oh, Kwan-Jung;Kim, Jin-Woong;Kim, Dong-Wook;Seo, Young-Ho
    • Journal of Broadcast Engineering
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    • v.25 no.4
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    • pp.587-597
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    • 2020
  • In this paper, we analyze the normalization that occurs when processing digital hologram and propose an optimized quantization method. In JPEG Pleno, which standardizes the compression of holograms, full complex holograms are defined as complex numbers with 32-bit or 64-bit precision, and the range of values varies greatly depending on the method of hologram generation and object type. Such data with high precision and wide dynamic range are converted to fixed-point or integer numbers with lower precision for signal processing and compression. In addition, in order to reconstruct the hologram to the SLM (spatial light modulator), it is approximated with a precision of a value that can be expressed by the pixels of the SLM. This process can be refereed as a normalization process using quantization. In this paper, we introduce a method for normalizing high precision and wide range hologram using quantization technique and propose an optimized method.

Design and Implementation of Class-AB High Power Amplifier for IMT-2000 System using Optimized Defected Ground Structure (최적화된 DGS 회로를 이용한 IMT-2000용 Class-AB 대전력증폭기의 설계 및 구현)

  • 강병권;차용성;김선형;박준석
    • Journal of the Institute of Convergence Signal Processing
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    • v.4 no.1
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    • pp.41-48
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    • 2003
  • In this paper, a new equivalent circuit for a defected ground structure(DGS) is proposed and adapted to design of a power amplifier for performance improvement. The DGS equivalent circuit presented in this paper consists of parallel LC resonator and parallel capacitance to describe the fringing fields due to the etched defects on the metallic ground plane, and also is used to optimize the matching circuit of a power amplifier. A previous research has also used a DGS for harmonic rejection and efficiency improvement of a power amplifier(1), however, there was no exact equivalent circuit analysis. In this paper, we suggest a novel design method and show the performance improvement of a class AB power amplifier by using the equivalent circuit of a DGS applied to output matching circuit. The design method presented in this paper can provide very accurate design results to satisfy the optimum load condition and the desirable harmonic rejection, simultaneously. As a design example, we have designed a 20W power amplifier with and without circuit simulation of DGS, and compared the measurement results.

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Optimization for the structure of all-optical filter transistor in nonlinear photonic crystals using Genetic Algorithm (유전자 알고리즘을 이용한 비선형 광자결정 내의 완전 광 필터 트랜지스터 구조의 최적화)

  • Lee, Hyuek-Jae
    • Journal of the Institute of Convergence Signal Processing
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    • v.9 no.2
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    • pp.129-134
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    • 2008
  • In this paper, we carry out the simulation for an optimal solution of one-dimensional nonlinear photonic crystal structure using Genetic algorithm, and show the proposed method to apply for photonic transistors. Unlike a conventional steepest descent method for an optimization, the proposed method based on Genetic Algorithm has advantages for finding out excellent solutions without any analytic forms, which can easily apply to other applications. Also, as several solutions around global minimum solution can be obtained, it is very good optimization tool to give us the patterns about the optimal structure of a photonic crystal transistor. To design an all-optical filter transistor, Neural network algorithm is firstly performed for an initial design and then Genetic Algorithm is finally used to get the optimal solution. From the simulation of one-dimensional photonic crystal transistor, 27dB of the switching On/Off ratio is obtained.

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A Study on Clustered OFCDM with Transmit Antenna Diversity and Coding Associated with Frequency Spreading over Frequency Selective Fading Channel (주파수 선택적 페이딩 채널에서 주파수 확산과 결합된 코딩과 송신안테나 다이버시티를 가진 Clustered OFCDM 시스템에 관한 연구)

  • Ryu Kwan-Woong;Park Yong-Wan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.3A
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    • pp.267-273
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    • 2006
  • This paper improves the effects of clustered OFCDM scheme considering the frequency diversity effect over a frequency selective fading channel. In OFCDM with frequency domain spreading compared to OFDM, we can increase uncorrelated symbols by frequency allocation method of correspondent symbols over the same antenna and different antenna after spreading. The simulation results show that the performance of proposed system is improved by approximately 4 dB in ${\sigma}=0.02{\mu}sec$, the performance is improved by approximately 2.5dB in large delay spread in a 12-path Rayleigh fading channel with overall the root mean squared delay spread and the maximum Doppler frequency of 20 Hz. Also, the required average received Eb/No at the average BER of $10^{-3}$ by optimum method is improved by approximately 2.0 dB, compared to that of STA-OFCDM with frequency rearrange. The new method does not require any bandwidth expansion any feedback from the receiver to the transmitter and its computation complexity is similar to clustered OFCDM.

SAW Filter Transmission Characteristics Design with Genetic Algorithm

  • Park, Kyu­-Chil;Kim, Seok­-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.8
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    • pp.1767-1775
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    • 2003
  • The SAW device is extensively used as a electro$.$mechanical band­pass filter in which a two­pairs of interdigital transducers are provided over the surface of the piezoelectric substrate. For the design requirement, the central frequency and the bandwidth of the passband, and the attenuation level of the stopband region are specified. The configuration is made so as to satisfy the specification given. The central frequency is mainly determined by the distance between the pair of the finger electrodes. The design is considered as an optimization problem with which the error norm, the distance between the desired characteristics and the calculated for a given model is to be minimized. The delta function model and the electrical equivalent circuit model are utilized to represent the SAW filter characteristics. Genetic algorithm is used for optimization in which apodization of the transducer fingers is chosen as a design variable.

Optimization of Stock Trading System based on Multi-Agent Q-Learning Framework (다중 에이전트 Q-학습 구조에 기반한 주식 매매 시스템의 최적화)

  • Kim, Yu-Seop;Lee, Jae-Won;Lee, Jong-Woo
    • The KIPS Transactions:PartB
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    • v.11B no.2
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    • pp.207-212
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    • 2004
  • This paper presents a reinforcement learning framework for stock trading systems. Trading system parameters are optimized by Q-learning algorithm and neural networks are adopted for value approximation. In this framework, cooperative multiple agents are used to efficiently integrate global trend prediction and local trading strategy for obtaining better trading performance. Agents Communicate With Others Sharing training episodes and learned policies, while keeping the overall scheme of conventional Q-learning. Experimental results on KOSPI 200 show that a trading system based on the proposed framework outperforms the market average and makes appreciable profits. Furthermore, in view of risk management, the system is superior to a system trained by supervised learning.

Design of Multipliers Optimized for CNN Inference Accelerators (CNN 추론 연산 가속기를 위한 곱셈기 최적화 설계)

  • Lee, Jae-Woo;Lee, Jaesung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.10
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    • pp.1403-1408
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    • 2021
  • Recently, FPGA-based AI processors are being studied actively. Deep convolutional neural networks (CNN) are basic computational structures performed by AI processors and require a very large amount of multiplication. Considering that the multiplication coefficients used in CNN inference operation are all constants and that an FPGA is easy to design a multiplier tailored to a specific coefficient, this paper proposes a methodology to optimize the multiplier. The method utilizes 2's complement and distributive law to minimize the number of bits with a value of 1 in a multiplication coefficient, and thereby reduces the number of required stacked adders. As a result of applying this method to the actual example of implementing CNN in FPGA, the logic usage is reduced by up to 30.2% and the propagation delay is also reduced by up to 22%. Even when implemented with an ASIC chip, the hardware area is reduced by up to 35% and the delay is reduced by up to 19.2%.

Design of Planetary Gear Drive Unit for Drive Conversion of Transfer case (Transfer case의 구동변환을 위한 유성기어장치 구동부 설계)

  • Youm, Kwang-Wook
    • Journal of the Korean Institute of Gas
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    • v.26 no.2
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    • pp.21-26
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    • 2022
  • Since the four-wheel drive transmits the driving force to all four wheels, the traction with the road surface increases, thereby increasing the driving force. However, it has the disadvantage of lowering fuel efficiency. Therefore, four-wheel drive is commonly used as a method of converting to optional four-wheel drive when necessary while driving in two-wheel drive. This selective four-wheel drive converts the driving force by mechanically changing the electric signal sent by the driver in the transfer case. In this study, in order to mechanically change the electrical signal, a reducer is applied to the motor to increase the torque to perform the function. Therefore, in this study, a reduction mechanism applicable to the motor inside the transfer case applied to convert the drive is derived, and the reduction ratio applying the planetary gear type is optimized accordingly. And based on the derived reduction ratio, two sets of planetary gears using a ring gear in common were applied to develop a planetary gear tooth type in which the input shaft and output shaft are decelerated in the same phase. Optimization design was carried out.

Block-based Learned Image Compression for Phase Holograms (신경망 기반 블록 단위 위상 홀로그램 이미지 압축)

  • Seung Mi Choi;Su yong Bahk;Hyun Min Ban;Jun Yeong Cha;Hui Yong Kim
    • Journal of Broadcast Engineering
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    • v.28 no.1
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    • pp.42-54
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    • 2023
  • It is an important issue to compress huge holographic data in a digital format. In particular, research on the compression of phase-only holograms for commercialization is noteworthy. Conventional video coding standards optimized for natural images are not suitable for compressing phase signals, and neural network-based compression model that can be optimized for phase signals can achieve high performance, but has a memory issue in learning high-resolution holographic data. In this paper, we show that by applying a block-based learned image compression model that can solve memory problems to phase-only holograms, the proposed method can demonstrate significant performance improvement over standard codecs even under the same conditions as block-based. Block-based learned compression model can provide compatibility with conventional standard codecs, solve memory problems, and can perform significantly better against phase-only hologram compression.

HSE Block : Automatic Optimization of the Number of Convolutional Layer Filters using SE Block (HSE Block : SE Block을 활용한 합성곱 신경망 필터 수 자동 최적화)

  • Tae-Wook Kim;Hyeon-Jin Jung;Ellen J. Hong
    • Journal of the Institute of Convergence Signal Processing
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    • v.23 no.3
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    • pp.179-184
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    • 2022
  • In this paper, we are going to study how we can automatically determine the number of convolutional filters for the optimal model without a search algorithm. This paper proposes HSE Block by connecting SE Block proposed in SENet to a convolutional neural network and connecting a convolutional neural network not learned at the bottom. An experiment was conducted to increase the number of filters by one per 3 epoch using two datasets for the HSEBlock model and to increase the number of filters by the value in the filter. Based on this experiment, the model was constructed with multi-layer HSE Block instead of layer HSE Block, and the experiment was carried out using a dataset that was more difficult to learn than the one used in the previous experiment. The effect of HSE Block was verified by conducting an experiment with the number of HSE Blocks set to 2, 3, 4, and 5 on a dataset that is more difficult to learn than before.