- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Polarization attack on continuous-variable quantum key distribution
摘要： The shot-noise unit (SNU) is a crucial factor for the practical security of a continuous-variable quantum key distribution system. In the most widely used experimental scheme, the SNU should be calibrated first and acts as a constant during the key distribution. However, the SNU of a practical system is dependent on the various parameters of the local oscillator (LO), which can be controlled by the eavesdropper in the open channel. In this paper, we report a quantum hacking method to control the practical SNU by using the limited compensation rate of the polarization compensation. Since the compensation is only based on of the polarization measurement results of part of LO pulses, the polarization of other unmeasured pulses may not be compensated correctly, which can be utilized by the eavesdropper to control the practical SNU. The simulation and experiment results indicate that the practical SNU can be controlled by the eavesdropper. Thus, the eavesdropper can use the fact that the practical SNU is no longer equals to the calibrated one to control the excess noise and final key rate.
关键词： shot noise unit,polarization compensation,continuous-variable quantum key distribution,quantum hacking
更新于2025-09-23 15:23:52
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[IEEE NAECON 2018 - IEEE National Aerospace and Electronics Conference - Dayton, OH, USA (2018.7.23-2018.7.26)] NAECON 2018 - IEEE National Aerospace and Electronics Conference - Impact of dielectric and magnetic losses on the negative index characteristics of a chiral material with first-order sideband dispersion
摘要： Electromagnetic propagation in chiral materials under first-order dispersion is examined for negative indices under non-conductive losses. Three loss scenarios are considered, viz., dielectric (complex permittivity) losses; magnetic (complex permeability) losses; and a combination of both types of losses to investigate the overall impact of the losses on the emergence of negative index bands.
关键词： complex permittivity and permeability,loss compensation,plane wave polarization,material dispersion,negative index bands,Negative refractive index
更新于2025-09-23 15:22:29
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[IEEE 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Beijing, China (2018.10.20-2018.10.22)] 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Design of PFC in Wireless Charging System for Electric Vehicle
摘要： A power factor correction (PFC) circuit is constructed, based on average period compensation method(APCM) in this paper. The cut-off frequency 2kHz and 10Hz are closed for current loop and voltage loop, and the phase margin of each loop is 80 degrees. By contrasting the THD of fundamental wave calculated to the 40th and the peak value of voltage ripple wave, PI values and transfer functions of both current loop and voltage loop are got. Then the input current and output voltage in PFC steady operation are simulated, and results are in accord with the small-signal model. In Simulink, the output capacitance is charged in advance and saturation controller is adopted, by which the overshoot of output voltage decreases by 6.3%, and the THD of input current is only 3.76%, which meet the demands for power-factor correction in wireless charging system for EV.
关键词： Average Period Compensation Method,Active PFC Circuit,Wireless Charging Technology
更新于2025-09-23 15:22:29
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Opto-electronic platform tracking control of multi-rotor unmanned aerial vehicles based on composite disturbance compensation
摘要： Airborne opto-electronic platforms are very important in unmanned aerial vehicle systems. The stability and tracking performance of airborne opto-electronic platforms are easily affected by disturbance factors, making compensating for those disturbances a very prominent issue. In this paper, compared to the traditional disturbance observer, an improved velocity signal based disturbance observer (IVDOB) is particularly designed to compensate for the disturbance. Then its capability, robustness, and stability are discussed. For improving the stabilization accuracy and tracking performance of airborne opto-electronic platforms, the universal approximation property of fuzzy systems is used to compensate the disturbance further and an adaptive fuzzy control system based on IVDOBs is proposed. To validate the scheme, a series of experiments were carried out. The results show that the proposed control scheme can achieve reliable control precision and satisfy the requirements of airborne opto-electronic platform tasks.
关键词： Multi-rotor unmanned aerial vehicle,airborne opto-electronic platform,composite disturbance compensation,disturbance observer,approximation property
更新于2025-09-23 15:22:29
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On loss compensation, amplification and lasing in metallic metamaterials
摘要： The design of metamaterials, which are artificial materials that can offer unique electromagnetic properties, is based on the excitation of strong resonant modes. Unfortunately, material absorption—mainly due to their metallic parts—can damp their resonances and hinder their operation. Incorporating a gain material can balance these losses, but this must be performed properly, as a reduced or even eliminated absorption does not guarantee loss compensation. Here we examine the possible regimes of interaction of a gain material with a passive metamaterial and show that background amplification and loss compensation are two extreme opposites, both of which can lead to lasing.
关键词： loss compensation,split-ring resonator,active media,lasing,nanophotonics,Metamaterials
更新于2025-09-23 15:22:29
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Phase aberration compensation for digital holographic microscopy based on double fitting and background segmentation
摘要： We propose a purely automatic and accurate phase aberration compensation method in digital holographic microscopy for phase-contrast imaging of living cells. At first, a least-squares fitting procedure is implemented to correct a large proportion of the phase aberrations. Subsequently, the flat phase background is retrieved based on phase gradient and image segmentation. Finally, the residual phase aberrations are eliminated in another least-squares fitting procedure performed within the background region. This method needs no manual intervention or prior knowledge of optical setup. Not only phase curvature but also high order aberrations could be corrected without extra components. It outperforms the phase-variation-minimization method in terms of noise robustness and calculation speed. The performance of the proposed method is demonstrated with simulated and experimental results.
关键词： Phase measurement,Digital holographic microscopy,Aberration compensation
更新于2025-09-23 15:22:29
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Analysis of the Subdivision Errors of Photoelectric Angle Encoders and Improvement of the Tracking Precision of a Telescope Control System
摘要： Photoelectric angle encoders, working as position sensors, have a great influence on the accuracy and stability of telescope control systems (TCS). In order to improve the tracking precision of TCS, a method based on subdivision error compensation for photoelectric angle encoders is proposed. First, a mathematical analysis of six types of subdivision errors (DC error, phase error, amplitude error, harmonic error, noise error, and quantization error) is presented, which is different from the previously used analysis based on the Lissajous figure method. In fact, we believe that a mathematical method is more efficient than the figure method for the expression of subdivision errors. Then, the distribution law and period length of each subdivision error are analyzed. Finally, an error compensation algorithm is presented. In a real TCS, the elevation jittering phenomenon occurs, which indicates that compensating for the amplitude error is necessary. A feed-forward loop is then introduced into the TCS, which is position loop- and velocity loop-closed, leading to a decrease of the tracking error by nearly 54.6%, from 2.31” to 1.05”, with a leading speed of 0.25°/s, and by 40.5%, from 3.01” to 1.79”, with a leading speed of 1°/s. This method can realize real-time compensation and improve the ability of TCS without any change of the hardware. In addition, independently of the environment and the kind of control strategy used, this method can also improve the tracking precision presumably because it compensates the measuring error inside the photoelectric angle encoder.
关键词： subdivision errors,tracking precision,real-time compensation,amplitude error,photoelectric angle encoders,telescope control systems
更新于2025-09-23 15:22:29
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Deep Distillation Recursive Network for Remote Sensing Imagery Super-Resolution
摘要： Deep convolutional neural networks (CNNs) have been widely used and achieved state-of-the-art performance in many image or video processing and analysis tasks. In particular, for image super-resolution (SR) processing, previous CNN-based methods have led to significant improvements, when compared with shallow learning-based methods. However, previous CNN-based algorithms with simple direct or skip connections are of poor performance when applied to remote sensing satellite images SR. In this study, a simple but effective CNN framework, namely deep distillation recursive network (DDRN), is presented for video satellite image SR. DDRN includes a group of ultra-dense residual blocks (UDB), a multi-scale purification unit (MSPU), and a reconstruction module. In particular, through the addition of rich interactive links in and between multiple-path units in each UDB, features extracted from multiple parallel convolution layers can be shared effectively. Compared with classical dense-connection-based models, DDRN possesses the following main properties. (1) DDRN contains more linking nodes with the same convolution layers. (2) A distillation and compensation mechanism, which performs feature distillation and compensation in different stages of the network, is also constructed. In particular, the high-frequency components lost during information propagation can be compensated in MSPU. (3) The final SR image can benefit from the feature maps extracted from UDB and the compensated components obtained from MSPU. Experiments on Kaggle Open Source Dataset and Jilin-1 video satellite images illustrate that DDRN outperforms the conventional CNN-based baselines and some state-of-the-art feature extraction approaches.
关键词： feature distillation,compensation unit,ultra-dense connection,super-resolution,video satellite,remote sensing imagery
更新于2025-09-23 15:22:29
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20?Gb/s Hybrid CWDM/DWDM for Extended Reach Fiber to the Home Network Applications
摘要： Five channels hybrid DWDM/CWDM fiber to the home optical network with bit rate of 20 Gb/s has been demonstrated in this paper. The role of DWDM to increase the network capacity with the same service quality has been illustrated. Upgrading the already running network to cover the extra number of subscribers and the different destinations that asked for the fiber links is discussed. The role of the dispersion compensating fiber (DCF) in enhancing the network has been demonstrated. The comparison between the different methods of the dispersion compensation using DCF is illustrated. The effect of the DWDM on the network and optimizing the transmission power to achieve the required distances are discussed.
关键词： Fiber to the home,CWDM,Dispersion compensation fiber,Long haul reach,DWDM
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - SH-Type Spurious Response Free TC-SAW Resonators Using Low Acoustic Velocity Rayleigh SAW on LiNbO<inf>3</inf> Substrate
摘要： In this paper, we describe the behavior of the spurios resonance caused by shear-horizontal (SH) type surface acoustic wave (SAW) devices in low acoustic velocity (LAV) Rayleigh-type SAW structures. It is well known that an SH-type SAW or Rayleigh-type SAW device appears near the main resonance on LiNbO3 (LN) substrates, which causes various undesired effects on the device characteristics. However, they are often non-negligible in practical use. In order to explore a solution of this problem, we theoretically and experimentally investigated the variation of the SH-type SAW resonance in the low acoustic velocity (LAV) Rayleigh-type SAW structure on LN substrates, which is a new LAV-SAW structure with a higher performance temperature-compensated (TC) SAW device (TC-SAW) technology. As a result, we revealed that the SH-type SAW can be almost zero even if various parameters are changed. Moreover, very small sized and TC-SAW devices can be realized using this new technology.
关键词： temperature compensation,SAW,Rayleigh-type SAW,acoustic velocity,LiNbO3,SH-type SAW
更新于2025-09-23 15:22:29