Trojan Horse Attack Free Fault-Tolerant Quantum Key Distribution Protocols Using GHZ States

Recently, Yang and Hwang (Quantum Inf. Process. 13(3): 781–794, 19) proposed two fault-tolerant QKD protocols based on their proposed coding functions for resisting the collective noise, and their QKD protocols are free from Trojan horse attack without employing any specific detecting devices (e.g., photon number splitter (PNS) and wavelength filter). By using four-particle Greenberger-Horne-Zeilinger (GHZ) state and four-particle GHZ-like state in their proposed coding functions, Yang and Hwang’s QKD protocols can resist each kind of the collective noise–collective-dephasing noise, collective-rotation noise. However, their proposed coding function can be improved by the utilization of three-particle GHZ state (three-particle GHZ-like state) instead of four-particle GHZ state (four-particle GHZ-like state) that will eventually reduce the consumption of the qubits. As a result, this study proposed the improved version of Yang and Hwang’s coding functions to enhance the qubit efficiency of their schemes from 20 % to 22 %.     

Creating and transporting Trojan wave packets

Nondispersive localized Trojan wave packets with n(i) ~ 305 moving in near-circular Bohr-like orbits are created and transported to localized near-circular Trojan states of higher n, n(f) ~ 600, by driving with a linearly polarized sinusoidal electric field whose period is slowly increased. The protocol is remarkably efficient with over 80% of the initial atoms being transferred to the higher n states, a result confirmed by classical trajectory Monte Carlo simulations.     

Extracting Past-Future Vacuum Correlations Using Circuit QED

We propose a realistic circuit QED experiment to test the extraction of past-future vacuum entanglement to a pair of superconducting qubits. The qubit P interacts with the quantum field along an open transmission line for an interval T_{on} and then, after a time-lapse T_{off}, the qubit F starts interacting for a time T_{on} in a symmetric fashion. After that, past-future quantum correlations will have transferred to the qubits, even if the qubits do not coexist at the same time. We show that this experiment can be realized with current technology and discuss its utility as a possible implementation of a quantum memory.     

Binocular, Monocular and Dichoptic Pattern Masking

It has been reported that a quadratic summation rule can account for threshold versus masker contrast (TvC) functions for binocular, monocular and dichoptic masking. However, the present study suggests that inputs from two eyes are summed in different ways. Foleys model was revised to describe TvC functions for binocular, monocular and dichoptic masking. The revised model has the following two characteristics. First, the revised model receives two monocular inputs. Secondly, excitations and inhibitory signals are subjected to nonlinear transducer functions before and after summation of the monocular signals. A two-alternative forced-choice procedure was used to measure contrast thresholds for Gaussian windowed sine-wave gratings (target) in the presence of sine-wave gratings (masker). Thresholds were measured for 11 masker contrasts and the three masking conditions. It was shown that this revised model fitted the data resonably well. The revised model indicates how monocular inputs are summed in contrast processing.     

High Level Languages Implementation and Analysis of 3D Navier-Stokes Solvers

In this work we introduce PRIN-3D (PRoto-code for Internal flows modeled by Navier-Stokes equations in 3-Dimensions), a new high level algebraic language (Matlab$^®$) based code, by discussing some fundamental aspects regarding its basic solving kernel and by describing the design of an innovative advection scheme. The main focus was on designing a memory and computationally efficient code that, due to the typical conciseness of the Matlab coding language, could allow for fast and effective implementation of new models or algorithms. Innovative numerical methods are discussed in the paper. The pressure equation is derived with a quasi-segregation technique leading to an iterative scheme obtained within the framework of a global preconditioning procedure. Different levels of parallelization are obtainable by exploiting special pressure variable ordering patterns that lead to a block-structured Poisson-like matrix. Moreover, the new advection scheme has the potential of a controllable artificial diffusivity. Preliminary results are shown including a fully three-dimensional internal laminar flow evolving in a relatively complex geometry and a 3D methane-air flame simulated with the aid of libraries based on the Flamelet model.     

印刷电路板预电离3.6 kW TEA CO2激光器

在TEA CO₂激光器中采用印刷电路板预电离结构,在单节放电体积为5cm×4cm×90cm 的两节串连的激光器中获得了20.4 J单脉冲能量输出,电光转换效率达12.8％.激光器重复频率工作时,气体清洗系数大于3,在最高重复频率180 Hz下获得了3.6 kW平均输出功率.     

Efficient Analysis of Millimeter Wave Circuit Using Numerical Calibration Technique

In this paper, A numerical technique, called short-open calibration (SOC), in conjunction with edge-based finite element method (FEM) is employed to analyze millimeter wave circuit that can be segmented into two distinct section: static model of feedlines and dynamic model of circuit discontinuity. The derivation of reflection coefficient of 3D discontinuities is arranged in two steps. In the first step, this SOC technique is incorporated into the FEM for mesh truncation of computaional domain. In this way, much faster convergence is achieved for large-sparse linear matrix equations from FEM by this termination than by perfectly matching layers (PML). The field distribution of the dominated mode in uniform feedlines and entire circuit is obtained individually by exciting a pair of even and odd impressed voltages along the struture. In step two, Scattering parameters based on the voltages and current defintion is calculated by integral of electric and magnetic fields. Numerical solutions for a class of planar circuit discontuities are very well compared with those published in the available literatures.     

Masking effects in binaural detection and interaural time discrimination

This study was designed to investigate the effects of masker level and frequency on binaural detection and interaural time discrimination. Detection and interaural time discrimination of a 700-Hz sinusoidal signal were measured as a function of the center frequency and level of a narrow-band masking noise. The masker was a continuous, diotic, 80-Hz-wide noise that varied in center frequency from 250 to 1370 Hz. In the detection experiment, the signal was presented either diotically (NoSo) or interaurally phase reversed (NoS pi). In the interaural time discrimination experiment, the signal level needed to discriminate a 30-microseconds interaural delay was measured. As would be expected, the presence of the masker has a greater effect on NoSo detection than NoS pi detection, and for masker frequencies at or near the signal frequency. In contrast, interaural time discrimination can be improved by the presence of a low-level masker. Also, performance improves more rapidly as the signal/masker frequency separation increases for NoSo detection than for interaural time discrimination and NoS pi detection. For all three tasks, significant upward spread of masking occurs only at the highest masker level; at low masker levels, there is a tendency toward downward spread of masking.     

基于混合蛙跳算法的时序电路测试生成

阐述了将混合蛙跳算法应用在时序电路自动测试生成的实现方法和结果;根据时序电路自身的结构特点,构造了测试生成的混合蛙跳表达方式,设计了自动测试生成离散混合蛙跳模型,通过群体中青蛙间的合作和竞争产生的群智能指导快速优化收敛;最后,根据国际标准时序电路进行了验证试验;结果表明,与同类算法相比,该算法获得了较小的测试集和较高的故障覆盖率。     

Masking Quantum Information Encoded in Pure and Mixed States

Masking of quantum information means that information is hidden from a subsystem and spread over a composite system. Modi et al. proved in [Phys. Rev. Lett. 120, 230501 (2018)] that this is true for some restricted sets of nonorthogonal quantum states and it is not possible for arbitrary quantum states. In this paper, we discuss the problem of masking quantum information encoded in pure and mixed states, respectively. Based on an established necessary and sufficient condition for a set of pure states to be masked by an operator, we find that there exists a set of four states that can not be masked, which implies that to mask unknown pure states is impossible. We construct a masker S^? and obtain its maximal maskable set, leading to an affirmative answer to a conjecture proposed in Modi’s paper mentioned above. We also prove that an orthogonal (resp. linearly independent) subset of pure states can be masked by an isometry (resp. injection). Generalizing the case of pure states, we introduce the maskability of a set of mixed states and prove that a commuting subset of mixed states can be masked by an isometry S^◇ while it is impossible to mask all of mixed states by any operator. We also find the maximal maskable sets of mixed states of the isometries S^? and S^◇, respectively.

     

基于听觉掩蔽效应的(ψ)阶STSA-MMSE语音增强算法

提出人耳掩蔽效应与阶STSA- MMSE(Short Time Spectral Amplitude-Minimum Mean Square Error)算法动态结合的语音增强算法.该算法通过引入参量提高了STSA-MMSE 算法的实时性,同时结合人耳掩蔽效应,动态的确定增强滤波器的传递函数以适应语音信号的变化,来提高语音质量.实验结果表明,和STSA-MMSE 算法相比,该算法在实时性方面有很大改善,并使降噪后的语音信号有较小的失真,同时很好地抑制了音乐噪音.     

特洛伊木马方法及其应用最新进展

特洛伊木马方法是实验核天体物理中一种重要的间接测量方法,特别适合极低能区带电粒子裸核反应截面测量。在介绍特洛伊木马方法基本原理的基础上,重点讨论该方法近期在核天体物理应用中的一些重要实验结果,以及对未来研究的展望。主要介绍:AGB星s-过程关键中子源反应$ ^{{\rm{13}}}{\rm{C(\alpha ,n}}{{\rm{)}}^{{\rm{16}}}}{\rm{O}}$的间接测量,AGB星氟丰度超常现象相关核反应间接测量,以及最近热点–中等以上质量恒星碳燃烧核反应间接测量结果及相关争议。     

耦合腔链等效电路模型计算加速管场分布

介绍利用耦合腔链等效电路模型计算加速管场分布的原理和方法. 把加速腔链等效为谐振电路, 通过求解回路方程组, 并引入分流阻抗等物理参数, 可计算加速腔链整管的电磁场幅值和相位分布. 这一计算方法对加速管动力学设计和加速管几何参数设计有很好的指导意义, 并在16MeV返波加速管设计调试过程中得到了应用和验证.     

Masking patterns for synthetic vowels in simultaneous and forward masking

Two synthetic vowels /i/ and /ae/ with a fundamental frequency of 100 Hz served as maskers for brief (5 or 15 ms) sinusoidal signals. Threshold was measured as a function of signal frequency, for signals presented immediately following the masker (forward masking, FM) or just before the cessation of the masker (simultaneous masking, SM). Three different overall masker levels were used: 50, 70, and 90 dB SPL. In order to compare the data from simultaneous and forward masking, and to compensate for the nonlinear characteristics of forward masking, each signal threshold was expressed as the level of a flat-spectrum noise which would give the same masking. The internal representation of the formant structure of the vowels, as inferred from the transformed masking patterns, was enhanced in FM and "blurred" in SM in comparison to the physical spectra, suggesting that suppression plays a role in enhancing spectral contrasts. The first two or three formants were usually visible in the masking patterns and the representation of the formant structure was impaired only slightly at high masker levels. For high levels, filtering out the relatively intense low-frequency components enhanced the representation of the higher formants in FM but not in SM, indicating a broadly tuned remote suppression from lower formants towards higher ones. The relative phase of the components in the masker had no effect on thresholds in forward masking, indicating that the detailed temporal structure of the masker waveform is not important.     

视频法分析RC串联电路暂态过程

RC串联电路暂态充放电过程中,用手机拍摄并接在电容两端的数字电压表的变化过程。使用视频软件单帧播放功能记录瞬时电压随时间变化关系,绘制RC串联电路暂态过程的充放电曲线从而获得暂态过程的时间常数。     

Relationship Between Masking Levels and Phonatory Stability in Normal-Speaking Women

Disruption of auditory feedback such as masking has been shown to influence vocal production. A reliable finding is an increase in intensity level; an increase in fundamental frequency (F0) is a less robust finding. Research is lacking concerning the effects of auditory masking on measures of phonatory stability such as jitter and harmonics-to-noise ratio (HNR). This study investigated changes in intensity, F0, jitter, and HNR in 22 normally speaking college aged women. Subjects produced the vowel /a/ under three conditions: no masking level (0-dB ML), 50-dB ML, and 80-dB ML. Significant differences between conditions emerged for intensity; means for the other measures were not significantly different. Intraindividual differences between conditions for each variable are discussed in the framework of auditory versus kinesthetic feedback.     

基于粗糙集与小波反锐化掩模的图像增强

为了有效去除图像中的干扰噪音,改善模糊不清晰的有用边缘细节信息,提高图像的层次感和清晰度,提出将粗糙集和小波反锐化掩模相结合的方法来实现图像增强.运用粗糙集中的近似及等价属性关系将知识化后的图像划分成不同的区域,再根据估计好的阈值进行数据约简,实现有效去除噪音.运用小波反锐化掩模法对图像的轮廓及细节信息进行增强处理,完成图像的最终增强.实验结果表明,不论在主观的视觉效果上,还是客观的噪音均方误差,该方法的处理结果都是较为理想的.