• Title/Summary/Keyword: Oversampling

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Development of Oversampling Sigma-Delta Modulators with Nouniform Multibit Quantizer (비균일 양자기에 의한 과표본화율의 멀티빗트 시그마-델타 변조기의 개발)

  • 박종연;장목순
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.1
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    • pp.21-27
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    • 1997
  • We have proposed a new structure of the multibit ovesampling sigma-delta modulator. To solve the problkem of requring the accurate precision of the analog components, the novel digital correction scheme with a ROM-table has been employed to enhance the SNR for the proposed system. This architecture has good features compared with the 1-bit approach, including significantly lower quantisation noise for a given oversampling ratio, as well as improve dstability characteristics. Then we hve shown the validity of the proposed system by use of the software developed for the performance evaluation and by realizing the system with SCFs(switched capacitor filters).

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Sigma-Delta A/D Converter for ADSL Modems (ADSL 모뎀용 시그마-델타 아날로그/디지털 변환기)

  • Han, Seung-Yub;Yu, Sang-Dae;Lee, Ju-Sang
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.950-953
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    • 2003
  • In this paper, sigma-delta A/D converter for ADSL modems using oversampling technique is designed. Conventionally, the oversampling A/D converter is consist of opamps, switched capacitors, quantizers, infernal D/A converters, and decimation filters. 3-bit flash A/D converter, 3-bit thermometer-based D/A converters, and sub-blocks are used for high speed operation. HSPICE simulator and CADENCE tool are used for verification and layout of the designed modulator. The internal A/D converter and D/A converters are operated at 130 MHz. In design of decimation filter Matlab is used for calculating coefficients and ModelSim and VHDL are used for design.

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3.125Gbps Reference-less Clock/Data Recovery using 4X Oversampling (레퍼런스 클록이 없는 3.125Gbps 4X 오버샘플링 클록/데이터 복원 회로)

  • Lee, Sung-Sop;Kang, Jin-Ku
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.10 s.352
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    • pp.28-33
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    • 2006
  • An integrated 3.125Gbps clock and data recovery (CDR) circuit is presented. The circuit does not need a reference clock. It has a phase and frequency detector (PFD), which incorporates a bang-bang type 4X oversampling PD and a rotational frequency detector (FD). It also has a ring oscillator type VCO with four delay stages and three zero-offset charge pumps. With a proposed PD and m, the tracking range of 24% can be achieved. Experimental results show that the circuit is capable of recovering clock and data at rates of 3.125Gbps with 0.18 um CMOS technology. The measured recovered clock jitter (p-p) is about 14ps. The CDR has 1.8volt single power supply. The power dissipation is about 140mW.

A Design of Variable Rate Clock and Data Recovery Circuit for Biomedical Silicon Bead (생체 의학 정보 수집이 가능한 실리콘 비드용 가변적인 속도 클록 데이터 복원 회로 설계)

  • Cho, Sung-Hun;Lee, Dong-Soo;Park, Hyung-Gu;Lee, Kang-Yoon
    • Journal of Korea Society of Industrial Information Systems
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    • v.20 no.4
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    • pp.39-45
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    • 2015
  • In this paper, variable rate CDR(Clock and Data Recovery) circuit adopting blind oversampling architecture is presented. The clock recovery circuit is implemented by using wide range voltage controlled oscillator and band selection method and the data recovery circuit is designed to digital circuit used majority voting method in order to low power and small area. The designed low power variable clock and data recovery is implemented by wide range voltage controlled oscillator and digital data recovery circuit. The designed variable rate CDR is operated from 10 bps to 2 Mbps. The total power consumption is about 4.4mW at 1MHz clock. The supply voltage is 1.2V. The designed die area is $120{\mu}m{\times}75{\mu}m$ and this circuit is fabricated in $0.13{\mu}m$ CMOS process.

Prediction of CDOM absorption coefficient using Oversampling technique and Machine Learning in upstream reach of Baekje weir (백제보 상류하천구간의 Oversampling technique과 Machine Learning을 활용한 CDOM 흡수계수 예측)

  • Kim, Jinuk;Jang, Wonjin;Kim, Jinhwi;Park, Yongeun;Kim, Seongjoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.46-46
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    • 2022
  • 유기물의 복잡한 혼합물인 CDOM(Colored or Chromophoric Dissolved Organic Matter)은 하천 내 BOD(Biological Oxygen Demand), COD(Chemical Oxygen Demand) 및 유기 오염물질과 상당한 관련이 있다. CDOM은 가시광선 영역에서 빛을 흡수하는 성질을 가지고 있으며, 최근 원격감지 기술로 CDOM을 모니터링하기 위한 연구가 진행되고 있다. 본 연구에서는 백제보 상류 23km 구간에서 3년(2016~2018) 중 13일의 초분광영상을 활용하여 머신러닝 기반 CDOM을 추정 알고리즘을 개발하고자 한다. 초분광영상은 400~970 nm의 범위의 4 nm 간격 127개 대역의 분광해상도와 2 m의 공간해상도를 가진 항공기 탑재 AsiaFENIX 초분광 센서를 통해 수집하였으며 CDOM은 Millipore polycarbonate filter (𝚽47, 0.2 ㎛)에서 여과된 CDOM 샘플 자료를 200~800 nm의 흡수계수 스펙트럼으로 추출하여 사용하였다. CDOM 값은 전체기간 동안 2.0~11.0 m-1의 값 분포를 보였으며 5 m-1이상의 고농도 구간 자료개수가 전체 153개 샘플자료 중 21개로 불균형하다. 따라서 ADASYN(Adaptive Synthesis Sampling Approach)의 oversampling 방법으로 생성된 합성 데이터를 사용하여 원본 데이터의 소수계층 데이터 불균형을 해결하고 모델 예측 성능을 개선하고자 하였다. 생성된 합성 데이터를 입력변수로 하여 ANN(Artificial Neural Netowk)을 활용한 CDOM 예측 알고리즘을 구축하였다. ADASYN 기법을 통한 합성 데이터는 관측된 데이터의 불균형을 해결하여 기계학습 모델의 CDOM 탐지 성능을 향상시킬 수 있으며, 저수지 내 유기 오염물질 관리를 위한 설계를 지원하는데 사용할 수 있을 것으로 판단된다.

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Fashion Category Oversampling Automation System

  • Minsun Yeu;Do Hyeok Yoo;SuJin Bak
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.1
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    • pp.31-40
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    • 2024
  • In the realm of domestic online fashion platform industry the manual registration of product information by individual business owners leads to inconvenience and reliability issues, especially when dealing with simultaneous registrations of numerous product groups. Moreover, bias is significantly heightened due to the low quality of product images and an imbalance in data quantity. Therefore, this study proposes a ResNet50 model aimed at minimizing data bias through oversampling techniques and conducting multiple classifications for 13 fashion categories. Transfer learning is employed to optimize resource utilization and reduce prolonged learning times. The results indicate improved discrimination of up to 33.4% for data augmentation in classes with insufficient data compared to the basic convolution neural network (CNN) model. The reliability of all outcomes is underscored by precision and affirmed by the recall curve. This study is suggested to advance the development of the domestic online fashion platform industry to a higher echelon.

Design of a 96-dB SNR and Low-Pass Digital Oversampling Noise-Shaping Coder for Low Supply Voltage (저 전압용 96-dB 신호대잡음비를 갖는 저역통과 디지털 과표본화 잡음변형기의 설계)

  • 김대정;손영철
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.5
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    • pp.91-97
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    • 2004
  • A digital over-sampling noise-shaping coder to achieve the processing accuracy for the audio signal bandwidth is designed. In order to implement an optimized design of the noise-shaping coder as a form of U (intellectual property), circuit design techniques that optimize the multiplication and the ROM architectures are proposed with emphasis on the low-voltage operation under 2.0 V and the minimization of the hardware resources. In the design and verification methodology, the overall architectures and the internal bit width have been determined through behavioral simulations. The overall performances including timing margin have been estimated through transistor-level simulations. Furthermore, the test results of the implemented chip using a 0.35-${\mu}{\textrm}{m}$ standard CMOS process proposed the validity of the proposed circuits and the design methodology.

Detecting Malicious Social Robots with Generative Adversarial Networks

  • Wu, Bin;Liu, Le;Dai, Zhengge;Wang, Xiujuan;Zheng, Kangfeng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.11
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    • pp.5594-5615
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    • 2019
  • Malicious social robots, which are disseminators of malicious information on social networks, seriously affect information security and network environments. The detection of malicious social robots is a hot topic and a significant concern for researchers. A method based on classification has been widely used for social robot detection. However, this method of classification is limited by an unbalanced data set in which legitimate, negative samples outnumber malicious robots (positive samples), which leads to unsatisfactory detection results. This paper proposes the use of generative adversarial networks (GANs) to extend the unbalanced data sets before training classifiers to improve the detection of social robots. Five popular oversampling algorithms were compared in the experiments, and the effects of imbalance degree and the expansion ratio of the original data on oversampling were studied. The experimental results showed that the proposed method achieved better detection performance compared with other algorithms in terms of the F1 measure. The GAN method also performed well when the imbalance degree was smaller than 15%.

Digital Image Processing Using Tunable Q-factor Discrete Wavelet Transformation (Q 인자의 조절이 가능한 이산 웨이브렛 변환을 이용한 디지털 영상처리)

  • Shin, Jong Hong
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.10 no.3
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    • pp.237-247
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    • 2014
  • This paper describes a 2D discrete-time wavelet transform for which the Q-factor is easily specified. Hence, the transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. The tunable Q-factor wavelet transform (TQWT) is a fully-discrete wavelet transform for which the Q-factor, Q, of the underlying wavelet and the asymptotic redundancy (over-sampling rate), r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The TQWT can also be used as an easily-invertible discrete approximation of the continuous wavelet transform. The transform is based on a real valued scaling factor (dilation-factor) and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its oversampling rate (redundancy), with modest oversampling rates (e. g. 3-4 times overcomplete) being sufficient for the analysis/synthesis functions to be well localized. Therefore, This method services good performance in image processing fields.

Frame Synchronization Scheme for High Oversampling Rate Based QPSK Receiver in the Underwater Acoustic Burst Transmission (초음파를 이용한 수중 버스트 전송에서 높은 과샘플율 기반 QPSK 수신기의 프레임동기 방안)

  • Park Jong-Won;Kim Seung-Geun;Lim Young-Kon;Kim Youngkil
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.8
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    • pp.462-468
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    • 2005
  • In this paper, we present a frame synchronization scheme for high oversampling rate based QPSK receiver system in the underwater acoustic burst transmission. The proposed frame synchronization scheme determines the frame synchronization by comparing a threshold value with the correlation between the received symbol sequence and rotated 16-symbol length CAZAC sequence, which is made by dividing into two 8-symbol length sequences and then concatenating the latter sequence and the former one. If the correlation value is bigger than the threshold value, the frame detector determines that the frame synchronization is achieved at that sample. Also, the approximated performance of designed frame detector is derived and it is well fit the simulated result.