- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Physical Layer Security of Hybrid Satellite-FSO Cooperative Systems
摘要： In this paper, we study the physical layer secrecy performance of a hybrid satellite and free-space optical (FSO) cooperative system. The satellite links are assumed to follow the Shadowed-Rician fading distribution; and the channel of the terrestrial link between the relay and destination is assumed to experience the Gamma-Gamma fading. For the FSO communications, the effects of different types of detection techniques (i.e., heterodyne detection and intensity modulation with direct detection) as well as the pointing error are considered. We derive exact analytical expressions for the average secrecy capacity (ASC) and secrecy outage probability (SOP) for both cases of Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying. The asymptotic analysis for the SOP is also conducted to provide more insights on the impact of FSO and satellite channels on secrecy performance. It is found that with the AF with fixed gain scheme, the secrecy diversity order of the investigated system is only dependent on the channel characteristics of the FSO link and the FSO detection type, whereas the secrecy diversity is zero when the relay node employs DF or AF with variable-gain schemes.
关键词： land mobile satellite (LMS) channel,secrecy outage probability,hybrid satellite free-space optical (FSO) cooperative system,Physical layer security,average secrecy capacity
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Singapore (2018.5.22-2018.5.25)] 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Solar Plant Integration to Utility Grid with Improved Power Quality by using RNN-Hebbian-LMS Current Controller
摘要： In this paper a new topology of current control technique is proposed, to transfer the improved quality of power produced from the solar plant to the utility grid. Also, a high-gain high-efficient converter driving with Kalman MPPT is used to boost the low voltage levels of the PV array. The proposed control uses recurrent neural network RNN-Hebbian -LMS based current controller to achieve the better performance in terms of power quality. The RNN network uses feedback signals to control the current flow from solar plant to the utility grid. The Hebbian - LMS (least mean square) algorithm is used to update the weights of the RNN based current controller. The main advantage of the RNN-Hebbian-LMS current control technique is to maintain the constant voltage. Besides, it also provides system stability over wide range of parameter variations and damp out the oscillations quickly. The proposed algorithm is able to overcome the stability and sensitivity problems incurred with the conventional PI current controller. The simulation results will be compared with the conventional PI and proposed RNN-Hebbiab-LMS current controllers. Finally, the proposed current controller shows the improved power quality, quick settling time and more stable comparing with the conventional controllers.
关键词： Least Mean Square (LMS),Utility Grid,Solar Plant,High-Gain converter,PV array,Maximum Power Point Tracking (MPPT),Recurrent Neural Network (RNN)
更新于2025-09-23 15:21:21
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An Integration of Solar Photovoltaic Generation to Three-Phase Utility Using Adaptive Control Algorithm
摘要： This paper deals with the modified weighted least-mean square (LMS) control strategy for single-stage, solar photovoltaic (PV) grid-integrated system to enhance the power quality at common coupling point. This control algorithm has fast convergence, fewer oscillations, fast dynamic response, and good steady-state performance than the other LMS-based control algorithm. The incremental conductance-based maximum power point tracking technique is used to obtain the crest power from the PV array, which is used to sustain DC link voltage by proportional–integral controller. The fundamental component of load current is extracted using this proposed control technique to estimate the reference currents of grid. This proposed control algorithm addresses various power quality concerns such as harmonics reduction, power factor correction, and load unbalancing. The VSC of PV array-interfaced grid system feeds real power to the loads, and surfeit real power is injected into the distribution network. The dynamic performance of proposed single-stage PV-fed three-phase system is validated into the MATLAB\Simulink environment at nonlinear loads, and simulated results are validated with test results on an experimental prototype at different environmental conditions such as varying solar irradiation and load unbalancing. Test results are found satisfactory, and total harmonic distortions of grid currents are observed well within limits of the IEEE-519 standard.
关键词： LMS,Voltage source converter (VSC),Power quality,Distributed grid,Solar PV generation
更新于2025-09-23 15:21:01
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A Novel Two Dimensional Adaptive Filtering Algorithm for Image De-Noising via Fractional Gradient
摘要： In the recent decade it has been witnessed that raster images are the primary source of law enforcement, information for numerous applications such as bio-medical, geographical information system (GIS), photography, astronomy, etc. Primarily, the quality of raster images compromises due to the surrounding factors of these applications. Because, it is very difficult to control surrounding parameter (light, motion, distance) while acquiring images. Therefore, the image acquisition in these applications is very much prone to the noise. In the literature, researchers have targeted this issue and have already devised classical image filters for image de-noising. Afterwards, in the recent years the performance of classical filtering was further improved by employing two dimensional adaptive filters (2-DAF) for image de-noising and enhancement. In the literature, researchers have reported the performance comparisons of various 2-DAF specifically for image restoration, enhancement, estimation, and de-noising. In this paper an extended version of one dimensional fractional least mean square (1-DFLMS) to two dimensional fractional least mean square (2-DFLMS) is presented. Moreover the performance of the proposed algorithm has been rigorously compared with the existing and most employed 2-DAF algorithm namely, two dimensional least mean square (2-DLMS), two dimensional variable step size least mean square (2-DVSSLMS). The simulation results illustrate the notable performance edge of the proposed algorithm with the existing approaches.
关键词： Image de-noising,least mean square (LMS),fractional least mean square (FLMS),two-dimensional adaptive filtering,variable step size least mean square (VSSLMS)
更新于2025-09-23 15:21:01
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Quasi blind carrier phase estimation scheme for special-shaped circular (7,1) modulation in high-speed visible light communication
摘要： A novel digital signal processing (DSP) scheme for special-shaped circular (7,1) modulated signals based on quasi blind carrier phase estimation (QBCPE) is proposed. The results show that applying 0.33‰ overhead QBCPE provides similar performance as 3% training sequence data-aided equalization of least mean square (LMS) algorithm.
关键词： Constant Modulus Algorithm (CMA),visible light communication (VLC),least mean square (LMS),circular (7,1) modulation,quasi blind carrier phase estimation (QBCPE)
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Autonomous Path Planning by Unmanned Aerial Vehicle (UAV) for Precise Monitoring of Large-Scale PV plants
摘要： This paper presents a 3.6 GHz low-noise fractional-N digital phase-locked loop (PLL) that achieves low in-band phase noise. Phase detection is carried out by a proposed 10-bit, 0.8 ps resolution time-to-digital converter (TDC) using a charge pump and a successive-approximation-register analog-to-digital converter (SAR-ADC) with low power and small area. The latency of the TDC is addressed by the designed building blocks. The fractional spurs are reduced by dual-loop least-mean-square (LMS) calibration. A (cid:2)(cid:3)-less and MOS varactor-less LC digitally-controlled oscillator (DCO) is proposed whose frequency resolution is enhanced to 7 kHz (or a unit variable capacitance of 2.6 aF) using a bridging capacitor technique. A prototype chip is fabricated using a 65 nm CMOS process, occupying an active area of 0.38 mm2 and consuming a power of 9.7 mW at a reference frequency of 50 MHz. The measured in-band phase noise is 107.8 dBc/Hz to 110.0 dBc/Hz with a loop bandwidth of 1 to 5 MHz.
关键词： digitally controlled oscillator (DCO),least-mean-square (LMS),digital phase-locked-loop (PLL),time-to-digital converter (TDC),successive-approximation-register analog-to-digital converter (SAR-ADC),frequency synthesizer,CMOS,sub-picosecond resolution
更新于2025-09-23 15:19:57
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Online Deconvolution for Industrial Hyperspectral Imaging Systems
摘要： This paper proposes a hyperspectral image deconvolution algorithm for the online restoration of hyperspectral images as provided by whiskbroom and pushbroom scanning systems. We introduce a least-mean-squares (LMS)-based framework accounting for the convolution kernel noncausality and including nonquadratic (zero attracting and piecewise constant) regularization terms. This results in the so-called sliding block regularized LMS (SBR-LMS), which maintains a linear complexity compatible with real-time processing in industrial applications. A model for the algorithm mean and mean-squares transient behavior is derived and the stability condition is studied. Experiments are conducted to assess the role of each hyper-parameter. A key feature of the proposed SBR-LMS is that it outperforms standard approaches in low SNR scenarios such as ultra-fast scanning.
关键词： hyperspectral image,LMS,ZA-LMS,online deconvolution
更新于2025-09-19 17:15:36
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - MIMO equalization for few-mode fiber transmission systems
摘要： In this paper, it is verified in experiments that 2X2 multiple-input multiple-output(MIMO) can implement mode demultiplexing in a mode division multiplexing (MDM) system. The Least Mean Square (LMS) algorithm and the Normalized LMS (NLMS) algorithm are applied to MIMO equalization, and the equalization performance of the NLMS is more stable under the same power.
关键词： NLMS,MIMO equalization,LMS,Mode multiplexing
更新于2025-09-16 10:30:52
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Adaptive Wideband Beamforming Based on Digital Delay Filter
摘要： A novel adaptive wideband beamforming method is proposed, where beamforming is achieved by LMS based space-time adaptive filtering algorithm. Conventional broadband beamforming requires desired signal to be incident from the broadside i.e. direction normal to the array. The new method overcome this constraint by make use of digital delay filters which compensate the delay of receiving data, so that the signal of interest can be treated as if it had arrived from the broadside. Then LMS based space-time adaptive filtering algorithm is applied to achieve beamforming. Another advantage of the proposed methodology is its low computational complexity while sustaining high resolution. The effectiveness and advantage of the proposed methodology is theoretically investigated, and computational complexity is also addressed. To verify the theoretical analysis, computer simulations are implemented and comparisons with other algorithms are made.
关键词： Wideband beamforming,Digital delay filter,LMS algorithm,Space-time adaptive filtering
更新于2025-09-09 09:28:46
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[IEEE 2017 International Conference on Current Trends in Computer, Electrical, Electronics and Communication (CTCEEC) - Mysore, India (2017.9.8-2017.9.9)] 2017 International Conference on Current Trends in Computer, Electrical, Electronics and Communication (CTCEEC) - Mitigation of Lower Order Harmonics in a Grid-Connected Single-Phase PV Inverter using Shunt Active Filter
摘要： In this paper, a novel technique is proposed for mitigating lower order harmonics for single phase PV inverter using harmonic compensation. Step up transformer is used boost the voltage as per requirement of the grid. However, the implemented system will not introduce any lower order harmonics in the grid, but there are little chances of lower order harmonics, because of the dead time of inverter, core saturation and magnetizing current of the transformer, etc. In this paper, a unique approach is being presented which mitigates lower order harmonics using inverter current control. In this paper, adaptive harmonic compensation technique with additional active filter is being presented before feeding a supply to the grid. To obtain better control proportional resonant integral (PRI) controller is integrated. The advantage of using PRI controller is; it eliminates DC component from the control loop. In this paper, a PRI controller and LMS adaptive harmonic filter are also been discussed in great detail. In this paper, two systems are considered and compared one with an adaptive harmonic filter using SPWM, and in the second system, active filter is added before feeding inverter output to the step up transformer. Hence the first system is explained in great detail and for second system illustration of the active filter and obtained results are compared.
关键词： LMS adaptive filter,single phase PV inverter,harmonic distortion,PRI controller
更新于2025-09-09 09:28:46