One-step optical trinary signed-digit arithmetic using redundant bit representations

A simple one-step fully parallel trinary signed-digit arithmetic is proposed for parallel optical computing. This technique performs multidigit carry-free addition and borrow-free subtraction in constant time. The trinary signed-digit arithmetic operations are based on redundant bit representation of the digits. Optical implementation of the proposed arithmetic can be carried out using correlation or matrix multiplication based schemes. An efficient matrix multiplication based optical implementation that employs a fixed number of minterms for any operand length is developed. It is shown that only 30 minterms (less than recently reported techniques) are enough for implementing the one-step trinary addition and subtraction.     

Parallel Subtraction using LCLV and Lenslet Array in Optical Neural Networks

Basing on the method of wavelength and beam deviation encoding for implementing a bipolar optical neural networks, the subtraction between the positive and negative stimulation of a neuron can be converted to the addition by the normal and in verse states of a liquid crystal light value (LCLV). The summation can be performed by using a lenslet to focus the two light spots which represent the two stimulations. The pre liminary experimental results demonstrate the feasibility of the presental method.     

Symbolic substitution based flagged arithmetic unit design using polarization-encoded optical shadow-casting system

An extremely efficient modified-signed digit arithmetic unit based on symbolic substitution scheme is designed using the polarization-encoded optical shadow-casting system. Alternate design characteristics for both addition and subtraction are also presented.     

High-speed addition/subtraction/complement/doubling of quaternary numbers using optical nonlinearities and DQPSK signals

We propose an innovative approach to implementing multiple arithmetic functions of quaternary numbers using optical nonlinearities and differential quadrature phase-shift keying (DQPSK) signals. By adopting 100 Gbit/s DQPSK signals (A, B) and exploiting nondegenerate four-wave mixing (FWM) for addition/subtraction and degenerate FWM for complement and doubling in a single highly nonlinear fiber, we demonstrate 50 Gbaud/s simultaneous quaternary addition (A+B), dual-directional subtraction (A-B, B-A), complement (-A, -B), and doubling (2B). Power penalties less than 4 dB (addition), 3 dB (dual-directional subtraction), 2 dB (complement), and 3.1 dB (doubling) are observed at a bit-error rate of 10(-9).     

Trinary signed-digit arithmetic using an efficient encoding scheme

The trinary signed-digit (TSD) number system is of interest for ultrafast optoelectronic computing systems since it permits parallel carry-free addition and borrow-free subtraction of two arbitrary length numbers in constant time. In this paper, a simple coding scheme is proposed to encode the decimal number directly into the TSD form. The coding scheme enables one to perform parallel one-step TSD arithmetic operation. The proposed coding scheme uses only a 5-combination coding table instead of the 625-combination table reported recently for recoded TSD arithmetic technique.     

Canonical quaternary signed-digit arithmetic using optoelectronics symbolic substitution

A higher radix based signed-digit number system, such as the quaternary signed-digit (QSD) number system, allows higher information storage density, less complexity, fewer system components, and fewer cascaded gates and operations. An optoelectronics symbolic substitution scheme to handle the parallel quaternary signed-digit (QSD) arithmetic operations is proposed. A conversion algorithm is employed on the QSD numbers to simplify the addition process and reduce the number of the optical symbolic substitution rules. The optical addition operation of two QSD numbers is performed in one-step. An efficient shared content-addressable memory (SCAM)-based optical implementation of the QSD addition/subtraction operations employs a fixed number of minterms for any operand length. The canonical QSD number addition/subtraction scheme requires a significantly reduced number of minterms when compared with a similar previously reported technique.     

Theoretical analysis for the nonlinear frequency-selective joint-transform correlator

The theoretical analysis for a nonlinear and bipolar frequency-selective joint-transform correlator is reported without any impractical assumptions and verifield. The theoretical results are similar to those for a nonlinear and bipolar joint-transform correlator. In addition, the optimal threshold value for a bipolar frequency-selective joint-transform correlator is found to be zero. Moreover, a bipolar frequency-selective joint-transform correlator can provide a phase-only correlation signal with delta-function shape. The theoretical study for a DC-block bipolar frequency-selective joint-transform correlator is also given. It is shown that its autocorrelation peak remains the same as that without a DC block.     

Parallel quaternary signed-digit arithmetic operations: addition, subtraction, multiplication and division

A quaternary signed-digit number representations-based arithmetic unit is proposed. The arithmetic unit performs parallel one-step addition (subtraction), multiplication and division. We use the symbolic substitution technique to reduce the number of the computation rules involved in the computation rules. Fast parallel nonrecoded quaternary signed-digit multiplication is proposed using our proposed one-step quaternary signed-digit adder. Also, parallel quaternary signed-digit division is performed in constant time by exploiting an iterative conversion algorithm where in every iterative step a negation operation, an addition operation and two multiplication operations are performed. The execution times of the proposed QSD operations are proportional to log₂ n, where n are the length of operands.     

Differential System＇s Nonlinear Behaviour of Real Nonlinear Dynamical Systems

Chaos attractor behaviour is usually preserved if the four basic arithmetic operations, i.e. addition, subtraction, multiplication, division, or their compound, are applied. First-order differential systems of one-dimensional real discrete dynamical systems and nonautonomous real continuous-time dynamical systems are also dynamical systems and their Lyapunov exponents are kept, if they are twice differentiable. These two conclusions are shown here by the definitions of dynamical system and Lyapunov exponent. Numerical simulations support our analytical results. The conclusions can apply to higher order differential systems if their corresponding order differentials exist.     

Parallel computation of complex elementary functions using quaternary signed-digit arithmetic

A variety of algorithms for computing complex elementary functions based on the quaternary signed-digit (QSD) number system are proposed. An arithmetic unit that performs parallel one-step addition (subtraction), multiplication, and division is proposed to perform the computations of elementary functions such as square root, logarithmic, exponential, and other related functions. An optoelectronic-correlator-based architecture is suggested for implementing the proposed QSD elementary function algorithms. We used the symbolic substitution technique to reduce the number of the computation rules involved.     

Continuous-variable quantum key distribution based on photon addition operation

It is shown that the non-Gaussian operations can not only be used to prepare the nonclassical states, but also to improve the entanglement degree between Gaussian states. Thus these operations are naturally considered to enhance the performance of continuous variable quantum key distribution(CVQKD), in which the non-Gaussian operations are usually placed on the right-side of the entangled source. Here we propose another scheme for further improving the performance of CVQKD with the entangled-based scheme by operating photon-addition operation on the left-side of the entangled source.It is found that the photon-addition operation on the left-side presents both higher success probability and better secure key rate and transmission distance than the photon subtraction on the right-side, although they share the same maximal tolerable noise. In addition, compared to both photon subtraction and photon addition on the right-side, our scheme shows the best performance and the photon addition on the right-side is the worst.     

A Two-layer Intrinsically Fuzzy Morphology Image Processor Architecture

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在白光图象处理系统中利用色度测量作黑白图象的加法和减法

本文提供了一个新技术的理论和实验结果,即在白光图象处理系统中利用傅里叶频谱平面的彩色滤波和在输出平面的色度测量来作黑白透明图象的加法和减法。待处理的透明片的光强透过率可用原色的色度坐标来表示,两个图象的相加和相减的结果可在同一输出平面上以其相应的色度坐标值表示出来。 关键词：     

An all-optical integrated system for implementing arithmetic operation in 2’s complement method with the active participation of non-linear material based switches

Optics is regarded undoubtedly a potential and successful candidate in information and data processing because of its inherent parallelism. In last few decades several all-optical data processors, algebraic processors, arithmetic processors are proposed. Here in this communication the authors propose a completely new scheme for implementing binary data arithmetic in 2’s Complement method which is the most advantageous among all other established subtraction methods. To implement it we use non-linear material massively.     

Continuous-Variable Entanglement and Wigner-Function Negativity via Adding or Subtracting Photons

The performance of adding or subtracting photons on two-mode squeezed thermal states via examining the Einstein–Podolsky–Rosen (EPR) correlation, the Hillery–Zubairy (HZ) correlation, the fidelity of teleportation, and the negativity of Wigner function is theoretically investigated. The normalization factors and the teleportation fidelity are related to Jacobi polynomials, and the (evolved) Wigner functions are simply associated with two-variable Hermite polynomials. Compared with the original squeezed thermal states, the EPR correlation and the teleportation fidelity can be enhanced by photon subtraction and basically weakened by photon addition symmetric operations, but they cannot be enhanced for both photon addition and subtraction asymmetric cases. Also, HZ correlation can provide a better option relative to the EPR correlation in detecting the entanglement, and the fidelity for teleporting a squeezed state with a large squeezing can also be enhanced via photon addition symmetric operations, in contrast to teleporting a coherent state. Additionally, the nonclassicality is discussed in terms of the negativity of the (evolved) Wigner functions, which shows that photon addition and subtraction and the squeezing cannot restrain the deteriorate of nonclassicality, and the evolved Wigner functions become Gaussian (corresponding to vacuum) with long decay times as a result of amplitude decay.     

Engineering oxide resistive switching materials for memristive device application

Based on a unified physical model and first-principle calculations, a material-oriented methodology has been proposed to control the bipolar switching behavior of an oxide-based resistive random access memory (RRAM) cell. According to the material-oriented methodology, the oxide-based RRAM cell can be designed by material engineering to achieve the required device performance. In this article, a Gd-doped HfO₂ RRAM cell with excellent bipolar switching characteristics is developed to meet the requirements of memristive device application. The typical memristive characteristics of the Gd-doped HfO₂ RRAM cell are presented, and the mechanism is discussed.     

The use of dimensional renormalization schemes in unified theories

We present details and clarify some points in a recently proposed modification of the minimal subtraction adapted to unified theories. As an application we give a precise value of the superheavy gauge boson masses in SU(5).     

一种用于强噪声环境下语音识别的含噪Lombard及Loud语音补偿方法

针对语音识别中由于强噪声的影响而引起的Lombard和Loud效应进行研究,提出了基于训练数据的加性噪声和Lombard及Loud效应的联合补偿法。对于加性噪声是从谱减法的逆向角度对训练数据在频谱域采用谱加法;对于Lombard和Loud语音,则采用基于隐马尔可夫模型(HMM)状态标注的训练数据补偿,该方法同时考虑Lombard和Loud语音不同声学单元的不同状态在倒谱域的多种变化和多种变异情况下不同声学单元的音长及相对音长的变化。这种基于数据的多模式补偿使模型自动适应多种噪声和语音变异情况,在强噪声环境下具有很强的鲁棒性,并且不影响识别系统在正常环境或正常发音时的识别性能.同时,由于补偿是在训练过程中得到,不增加识别时的计算复杂度。     

Enhanced Phase Estimation in Parity-Detection-Based Mach–Zehnder Interferometer using Non-Gaussian Two-Mode Squeezed Thermal Input State

While the quantum metrological advantages of performing non-Gaussian operations on two-mode squeezed vacuum (TMSV) states have been extensively explored, similar studies in the context of two-mode squeezed thermal (TMST) states are severely lacking. This paper explores the potential advantages of performing non-Gaussian operations on TMST state for phase estimation using parity detection-based Mach–Zehnder interferometry and compares it with the TMSV case. To this end, a realistic photon subtraction, addition, and catalysis model is considered. A unified Wigner function of the photon subtracted, photon added, and photon catalyzed TMST state is derived, which is used to obtain the expression for the phase sensitivity. The results show that performing non-Gaussian operations on TMST states can enhance the phase sensitivity for significant squeezing and transmissivity parameter ranges. Because of the probabilistic nature of these operations, it is of utmost importance to consider their success probability. When the success probability is considered, the photon catalysis operation performed using a high transmissivity beam splitter is the optimal non-Gaussian operation. This contrasts with the TMSV case, where photon addition is observed as the most optimal. Further, the derived Wigner function of the non-Gaussian TMST states will be useful for state characterization and various quantum protocols.     

Digital partitioning for optical negabinary modular multiplication

Instead of using the truth look-up table residue arithmetic, a technique for multiplying two N-bit negabinary numbers, modulo (−2)^N −1 with digital partitioning, is introduced for optical computing. Both numbers are decomposed into k-bit bytes, and the product is obtained by the cyclic convolution of the sequences of the bytes. The operation with respect to other moduli can be performed similarly. The algorithm has such features as smaller computational complexity, ease of implementation, the ability to handle bipolar numbers without signs, and simple pre- and post-processing. As a proof-of-principle experiment, an optical correlator is used to perform the multiplication in parallel. The experimental results are given.