Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms

Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.

High Speed Polarization-Division Multiplexing Transmissions Based on the Nonlinear Fourier Transform

Polarization-division multiplexing(PDM)with modulation in the nonlinear frequency domain consisting of the discrete and/or continuous spectrum has been recently regarded as a useful method to be utilized in optical fiber communication system.It can compensate the optical fiber nonlinearity based on the nonlinear Fourier transform(NFT).In this paper,we combine PDM with the method of nonlinear frequency division multiplexing(NFDM)and demonstrate the achievable transmission rate by increasing the number of multiplexing nonlinear channels.For the selected subcarriers(i.e.32,64,and 128),the transmission rates are 64 Gbit/s,76.8 Gbit/s,and 109.7 Gbit/s respectively by applying 64-quadrature amplitude modulation(64-QAM)on the nonlinear continuous spectrum.For the transmission distance shorter than 1200 km,the transmission rate of 128-NFDM PDM system can even reach up to 153.6 Gbit/s.

Exploiting the Faster-Than-Nyquist Concept in Wavelength-Division Multiplexing Systems Using Duobinary Shaping

This paper begins with Nyquist wavelengthdivision multiplexing （WDM） and then introduces fasterthanNyquist. In fasterthanNyquist a certain amount of intersymbol interference （ISI） is accepted, which violates the fundamental principle of Nyquist WDM. This results in muchrelaxed transceiver bandwidth and simpler spectral design. However, in fasterthanNyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of fasterthanNyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, lowcomplexity receivers based on fasterthanNyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.

Interference Mitigation Techniques Using Receiver Processing and Resource Allocation

Heterogeneous network consists of the pico cells overlaid over the macro cell coverage area in a wireless cellular network. The pico cells are deployed to increase the capacity of the homogeneous network by reusing the spectrum further. However, more users will tend to be associated to the macro cell due to the fact that the transmit power of the pico cell is low. In order to increase the number of users associated to the pico cell, range extension techniques like biased association are used. This will cause severe interference to cell edge users of the pico cell from the macro cell causing degradation in throughput performance in the cell range extension area. In this paper, interference mitigation using receiver processing along with different scheduling techniques is proposed to improve the throughput, average delay, and the packet delivery ratio performance of the system. The performance comparison of the round robin, proportional fair and modified largest weighted delay first (MLWDF) algorithm for resource allocation using interference suppressing receiver is done, and analyzed. It is shown that the MLWDF algorithm achieves the highest throughput with minimum average delay of packets with the best delivery ratio.

MULTI-DIMENSIONAL MARKOV CHAIN–BASED ANALYSIS OF CONFLICT PROBABILITY FOR SPECTRUM RESOURCE SHARING

In this paper, we consider the optimal problem of channels sharing with het-erogeneous traffic （real-time service and non-real-time service） to reduce the data conflict probability of users. Moreover, a multi-dimensional Markov chain model is developed to analyze the performance of the proposed scheme. Meanwhile, performance metrics are derived. Numerical results show that the proposed scheme can effectively reduce the forced termination probability, blocking probability and spectrum utilization.

Pre-processing filter design at transmitters for IBI mitigation in an OFDM system

In order to meet the demands for high transmission rates and high service quality in broadband wireless communication systems, orthogonal frequency division multiplexing （OFDM） has been adopted in some standards. However, the inter-block interference （IBI） and inter-carrier interference （ICI） in an OFDM system affect the performance. To mitigate IBI and ICI, some pre-processing approaches have been proposed based on full channel state information （CSI）, which improved the system performance. A pre-processing filter based on partial CSI at the transmitter is designed and investigated. The filter coefficient is given by the optimization processing, the symbol error rate （SER） is tested, and the computation complexity of the proposed scheme is analyzed. Computer simulation results show that the proposed pre-processing filter can effectively mitigate IBI and ICI and the performance can be improved. Compared with pre-processing approaches at the transmitter based on full CSI, the proposed scheme has high spectral efficiency, limited CSI feedback and low computation complexity.

Real-time spatiotemporal division multiplexing electroholography for 1,200,000 object points using multiple-graphics processing unit cluster

Computationally, the calculation of computer-generated holograms is extremely expensive, and the image quality deteriorates when reconstructing three-dimensional(3 D) holographic video from a point-cloud model comprising a huge number of object points. To solve these problems, we implement herein a spatiotemporal division multiplexing method on a cluster system with 13 GPUs connected by a gigabit Ethernet network.A performance evaluation indicates that the proposed method can realize a real-time holographic video of a3 D object comprising ~1,200,000 object points. These results demonstrate a clear 3 D holographic video at32.7 frames per second reconstructed from a 3 D object comprising 1,064,462 object points.

ANALYSIS OF AN ATM MULTIPLEXER UNDER SELF-SIMILAR TRAFFIC

Recent empirical studies of the real traffic measurement show that the traditional traffic models cannot capture the character of long-range dependence of the traffic. And many computer simulations said that this character has large influences on the network performance. So fractal or self-similar models are more suitable to describe the modern traffic. But there is still little known about the performance of the multiplexer under self-similar traffic. In this paper, a quasi-self-similar traffic model (QSSP) is proposed. Using this model, the upper bond of the cell loss rate and multiplexing gain of the multiplexer are gotten when there are N i.i.d. QSSP inputs. If the sources have different parameters, an efficient numerical algorithm to get, this bond is proposed. Simulations indicate that our analysis is correct and accurate.

基于时频域联合数据辅助MIMO均衡算法的多维度复用千公里级相干传输系统

基于少模光纤的模式复用系统利用单根纤芯中的正交模式实现各独立信道的并行传输,能够有效提升系统容量,解决单模光纤系统的容量危机.本文联合使用模式复用、波分复用与偏振复用技术,基于六模渐变型光纤实现了80个波长通道下32 Gbaud四模双偏振16阶正交振幅调制信号的1000 km相干传输,并在接收端使用时频域联合数据辅助8×8多输入多输出最小均方算法,以补偿由光纤传输导致的模式耦合及模间色散等线性损伤.与传统的纯时域或纯频域多输入输出最小均方均衡算法相比,该算法分别实现了57.1%的收敛速度提升与25.1%的收敛误差下降.经过1000 km少模光纤传输后,80通道每个模式及偏振态的误码率均低于开销为20%的软判决前向纠错编码阈值2.4×10^(-2),系统净速率达68.2 Tbit/s.

一种具有积分电容复用功能的红外读出电路设计

为提高长波红外探测器的电荷处理能力,提出了一种积分电容复用技术。该技术将读出电路阵列分为奇偶行两个部分,使奇偶行像素分开进行积分读出。当所有的奇行像素积分时,所有的偶行像素均不进行积分。奇行像素复用偶行像素的积分电容,奇行像素积分结束后按行列顺序依次读出。同样地,当所有偶行像素积分时,奇行像素不进行积分,偶行像素复用奇行像素的电容,积分完成后偶行像素按顺序读出。相比于使用叠层电容来提高电荷处理能力的方法,积分电容复用技术更加有效且不受工艺限制。仿真结果表明,积分电容复用技术可将像素的等效积分电容提升至原来的2倍,使读出电路的电荷处理能力从20 Me^(-)提升至40 Me^(-)。

基于外部气相沉积的S+C+L波段低色散斜率大有效面积非零色散位移光纤的设计与制备

针对现有光纤无法满足宽带光密集波分复用系统传输和S+C+L波段粗波分复用的要求,设计了一种具有中心凹陷的三角形芯+环形的折射率剖面,利用外部气相沉积工艺制备了一种非零色散位移光纤,并通过调整第一芯层的相对折射率和第二芯层与第一芯层的半径比,探究了其对光纤衰减、色散斜率和有效面积等参数的影响。研究发现,当第一芯层的相对折射率逐渐增大且第二芯层与第一芯层半径比逐渐减小时,零色散波长和有效面积逐渐减小。当第一芯层的相对折射率在0.52%~0.53%,芯层半径比在2.6~2.7时,光纤的有效面积接近70μm^(2),零色散波长在1420 nm附近,在1550 nm波段的色散系数大于8 ps·nm^(-1)·km^(-1),色散斜率为0.059 ps·nm^(-2)·km^(-1),可以较好地抑制传输过程中光非线性效应,满足长途干线网与城域网的使用要求。

孝顺竹开花过程中DNA甲基化水平动态研究

以孝顺竹为材料,利用HPLC和MSAP技术在其未开花至开花的生长过程中进行甲基化水平的检测,分析竹子开花过程中基因组DNA甲基化的动态,以揭示DNA甲基化水平与竹子开花现象的相关性。结果显示:(1)孝顺竹基因组DNA甲基化率在不同的时间处于动态变化中,进入开花状态的孝顺竹植株其甲基化水平极显著低于开花竹丛中未开花植株和未开花竹丛;开花和未开花植株的总甲基化率分别为9.00%和12.42%,全甲基化率分别为5.06%和7.53%。(2)MSAP位点中有66.83%的位点在开花和未开花材料中甲基化状态保持一致,33.17%的位点在开花和未开花植株中发生甲基化变化:其中22.28%的位点在开花植株中发生完全的去甲基化,1.98%的谱带在开花植株中发生甲基化,8.91%的位点在开花和未开花材料中甲基化水平呈现上升或降低的趋势。研究表明,开花的孝顺竹同时发生甲基化和去甲基化,但发生去甲基化的概率明显大于发生甲基化的概率,最终导致其甲基化水平极显著降低。

基于偏振复用技术的半导体激光加工光纤耦合模块

与半导体激光Bar条相比,单管半导体激光器具有光束质量好,寿命长等优点,但由于其输出功率小,故在激光加工等领域的应用受到限制。为提高单管半导体激光器的输出功率,提出了基于偏振复用技术对多个单管半导体激光器进行光纤耦合的方法。首先,将16只808nm单管半导体激光器分成两个单元,通过空间合束将每个单元上的激光器发出的光合成一路;然后,利用偏振复用技术将两个单元发出的光束再次合束,通过自行设计的聚焦系统将合束后的光束耦合进光纤实现光纤输出,从而提高了半导体激光器光纤耦合模块的功率水平。实验显示,当工作电流为5.8A时,通过芯径为200μm、数值孔径(NA)为0.2的光纤的输出功率为67 W,耦合效率达到84%。此模块在功率和光束质量方面满足激光塑料焊接等应用的要求。

数据广播中的UCL标引与传输机制

UCL(UniformContentLocator)是作者、编者和读者进行语义沟通的工具 ,是数据广播中解决接收端数据信息的快速选择、信息过滤、智能代理和信息的主动服务的基础 .本文系统地介绍了数据广播中UCL的概念 ,提出了在数据广播中进行UCL标引的方法和两级复用方法 ,研究了数据广播的UCL W标引方案 ,研究了多映射与复用技术 ,最后给出了在数据广播的传输过程中 ,发送端对数据信息进行采集、标引、映射、复用、格式转换和调制的工作流程 .实验验证了理论方案的正确性和有效性 .

多重PCR的建立及黄淮麦区主要品种品质相关基因的鉴定

【目的】小麦加工品质由多个位点控制,而每个位点又有多个等位基因控制。建立品质性状多重PCR反应体系是提高分子标记辅助选择效率及降低成本的一种重要措施。【方法】选择影响小麦品质性状重要基因的分子标记,即高分子量谷蛋白亚基基因标记Ax2*、Bx14、Bx17和Dx5;低分子量谷蛋白亚基基因标记Glu-A3d;糯蛋白亚基Wx-B1基因标记BDFL-BRD和Wx-D1基因标记MAG269;1BL/1RS易位标记ω-sec及多酚氧化酶(PPO)活性基因标记PPO18。根据优质面包、优质面条亚基组成要求及引物的退火温度,建立3个多重PCR反应体系PCR-Ⅰ(Ax2*/Bx17/Dx5)、PCR-Ⅱ(BDFL-BRD/MAG269/PPO18)和PCR-Ⅲ(Bx14/Glu-A3d/ω-sec)。【结果】用构建的3个多重PCR对141份黄淮麦区小麦品种加工品质相关基因的分布情况进行了检测。结果表明Ax2*、Bx14、Bx17具有较低的分布频率,分别为4.3%、7.1%、1.4%;Dx5和Glu-A3d分布频率相对较高,分别为17.7%和27.7%;而1BL/1RS易位和低PPO活性(扩增片段为876bp)的材料分别占44.0%和51.8%;Wx-B1缺失材料占4.3%。在供试的141份材料中已有80份进行了高、低分子量谷蛋白亚基和黑麦碱的SDS-PAGE电泳检测,与本研究建立的多重PCR检测结果完全一致。【结论】建立的多重PCR体系可以准确、稳定、高效地检测9个小麦品质性状的基因组成。

空间精密OFDM测距技术

根据OFDM的时频特性,提出了一种新的空间测距方法.首先在时域对OFDM信号进行相关处理,得到距离的粗估计,在粗估计的基础上,利用OFDM不同子载波数据之间的相位差,得到距离的精确估计,根据精确估计的结果对粗估计的结果进行校正,从而得到最终的距离估计值.仿真结果表明,该方法的测距精度比采用延迟锁定环的伪码测距方法至少提高了4倍,并且在信噪比大于20 dB时,可以达到厘米级.

OFDM系统定时与频率偏移估计

在分析现有算法的基础上,提出了一种新的算法,并对其进行了仿真.仿真结果表明,无论是在多径信道还是在AWGN信道,该算法的定时估计和频率偏移估计的均方差都要优于最大似然算法和"集相关"算法.

基于物联网的智能家居系统网络层设计

目的提出一种智能网关与服务器协调合作的网络层解决方案,解决基于物联网的智能家居系统中各类感知设备、控制器与远程移动终端在网络层的互联互通问题.方法通过对系统网络层功能需求的分析,设计基于u C/OS-II操作系统的多任务并发网关,并结合Linux操作系统下的多进程技术与IO复用技术,开发网络层服务器,自主设计多层兼容可变长数据帧通信协议以保证系统各层次间数据交互的准确性与稳定性.结果系统网络层能够实现与感知层实时的数据交互,解决了多移动终端并发请求、网络层IO阻塞、数据交互时序混乱的问题.结论系统网络层具备高度的并发与实时性,可实现感知层中各类测控数据至应用层移动终端设备的双向数据交互,具有一定的工程应用价值.

微小型光纤陀螺组合分时复用技术

为了有效减小多轴光纤陀螺组合的功耗、体积和重量,实现光纤陀螺组合的微小型化,应用分时复用技术,提出了一种基于3×3耦合器,工作在850 nm短波长的光纤陀螺分时复用组合结构。分析了陀螺输出数据处理方法,得到了分时复用光纤陀螺组合的相对极限零偏稳定性。建立了分时复用光纤陀螺切换模型,揭示了分时复用导致光纤陀螺轴向切换必然存在一个过渡过程,分析了过渡过程对陀螺组合静态、动态特性的影响。结果显示,光纤陀螺组合的相对零偏稳定性是传感方法的2.1倍,最大输入信号检测带宽为1.1 kHz,标度因数的不对称性和非线性度均小于50×10-6。最后,通过仿真进行了实验验证,结果表明,该技术可以用于中低精度微小型多轴光纤陀螺组合中。

DH中STM-1/TU-12解复用的设计及FPGA实现

分析了同步数字体系SDH中STM-1信号解复用出TU-12的过程,对该电路中各个功能模块的设计思路进行了详细分析,采用了并行化处理方式,重点讨论了支路净荷抽取处理和FIFO的使用,进而完成了STM-1/TU-12解复用电路的设计与实现,创新性地将并行化、净荷调整后抽取和FIFO缓存结合使用,用以简化电路的设计。最后,在ALTERA公司的EP1C6T144C8器件环境下上进行了验证。