量子稳定子码的差错纠正与译码网络构建

寻找差错症状与差错算子之间映射关系是量子译码网络的核心内容,也是量子译码网络实现纠错功能的关键.给出了比特翻转差错症状矩阵和相位翻转差错症状矩阵的定义,将任意Pauli差错算子的差错症状表示为比特翻转差错症状矩阵和相位翻转差错症状矩阵的线性组合.研究发现,量子稳定子码的差错症状矩阵由其校验矩阵所决定,从而可将差错症状矩阵与差错算子之间的映射关系转化为校验矩阵与差错算子之间的映射关系,使得所有关于差错症状的分析都可以通过分析其校验矩阵来实现.这与经典线性码的差错症状与奇偶校验矩阵之间的关系类似,因此可以将经 关键词： 稳定子码 校验矩阵 差错症状 Pauli算子     

量子卷积码的编译码方法

对于量子卷积码理论的研究旨在保护长距离通信中的量子信息序列. 定义了量子态的多项式表示形式,根据Calderbank-Shor-Steane(CSS)型量子码的构造方法,给出了CSS型量子卷积码的一种新的编译码方法,描述了编译码网络. 该方法将码字基态变换为信息多项式与生成多项式的乘积,然后用量子态上的多项式乘法操作实现编译码网络. 最后借鉴经典卷积码的译码思想,给出了具有线性复杂度的量子Viterbi算法. 关键词： 量子信息 量子卷积码 编译码 纠错算法     

针对X-Z型Pauli信道的量子稀疏图码的反馈式和积译码算法

本文针对X-Z型Pauli量子信道构建了一个量子稀疏图码的反馈式和积译码算法.相比较之前的基本和积算法,该反馈式译码策略利用了错误图样的比较, 稳定子中相关元素的值,特别的还根据信道的特征充分考虑了各变量所占错误的比重,并由此来调整信息节点的概率分布.该反馈式策略起到了经典译码中的软判决技术的作用,不但克服了对称简并问题带来的不利影响,更重要的是还给译码器提供了更多的有效信息,从而大大提高了译码器的纠错译码能力.另外,反馈式译码和积译码算法是基于GF(4)的,大大拓展了和积译码器关于量子译码 关键词： 量子稀疏图码 和积算法 量子纠错码 量子信息     

An optical decoding architecture for the random iteration algorithm of iterated function system codes

A novel optical architecture based on the random iteration algorithm to decode iterated function system (IFS) codes is presented. The optical part of this system performs the affine transformations of IFS. The code values in the affine transformations of IFS are first translated into the modulation voltages of the electro-optic modulators (EOMS), with a specific probability. Then, the multiplication and addition operations can easily be performed. With the O/E and A/D converters, the light intensity is converted into an electrical signal to address a specific pixel at the display device. A fractal image is then progressively decoded pixel by pixel and superimposed on the display device. The computer simulation and some experimental results for the proposed architecture are provided for verification. The decoding speed is fast, the image quality is high, and the resolution of the generated fractals depends on the resolution of the display device itself.     

A resource-saving decoding scheme of the orthogonally concatenated codes for optical transport networks in FPGA

A decoding scheme of the orthogonally concatenated codes with low resource utilizations is proposed. In the optical transport networks (OTN), forward error-correction (FEC) techniques are used to reduce the errors which occur in transmissions. Two-orthogonal-concatenated (TOC) codes are widely used in FEC techniques for their powerful error-correction capabilities based on the iterative decoding procedure. However, the framing structure is complex so the decoding procedure is more difficult than the decoding of in–out concatenated codes. And the powerful error-correction capability relies on the multi-iterative decoding processing, thus how to effectively utilize the hardware resources is a very important problem. Especially when the decoding procedure is implemented in the field programmable gate array (FPGA) devices, effective optimizations are required for the limited resources. In this paper we present an iterative decoding scheme in FPGA with low resource utilizations. As an example, an actual engineering application under the G.975.1 recommendation is given to show the efficiency of the proposed design.     

Construction of optimal 2D variable-weight optical orthogonal codes for high-speed OCDMA networks

A new construction method of two-dimensional （2D） variable-weight optical orthogonal codes （VWOOCs） is proposed for high-speed optical code-division multiple-access （OCDMA） networks supporting multiple qualities of services （QoS）. The proposed codes have at most one-pulse per wavelength （AM-OPPW） property. An upper bound of the codeword cardinality of the 2D VWOOCs with AM-OPPW property is derived. It is then shown that the constructed codes have ideal correlation properties and optimal cardinality. Moreover, the code length and the bit-error-rate （BER） performance of the proposed codes are compared with those of the codes proposed previously.     

Millimeter-wave range for the quick evaluation of large reflector antennas with complex feeds

An automated millimeter-wave antenna range capable of measuring primary-feed structure patterns and transferring this data to a mainframe computer for secondary pattern computation is described. Its applicability to the rapid evaluation of complex feed structures as used in a Cassegrain antenna is illustrated. An example of a reflector antenna analysis is compared to a measured pattern.Supported by USAF Space Division, Contract F04701-84-C-0085.     

正交多相码连续波主动声呐回波检测算法设计

与常规脉冲式主动声呐相比,连续波主动声呐能够提高目标回波的时间处理增益和目标信息更新速率。该文提出一种由正交多相码合成的连续发射波形,分析了发射信号和目标回波模型,设计了多通道匹配滤波器组完成回波检测。为了进一步提高接收机检测性能,提出了多通道非相干积累的处理方法。通过数值仿真,分析提出的连续波形的多普勒分辨性能和目标信息更新率。通过蒙特卡罗法获取接收机工作特性曲线,比较了脉冲式主动声呐和连续波主动声呐在均匀混响背景下对单目标检测性能的差异。仿真结果表明,该文设计的连续波波形具有较好的多普勒分辨性能,在均匀混响背景下,回波检测算法能够明显提高单个目标的探测能力。     

Equivalences between three presentations of orthogonal and symplectic Yangians

Letters in Mathematical Physics - We prove the equivalence of two presentations of the Yangian $$Y(\mathfrak {g})$$ of a simple Lie algebra $$\mathfrak {g}$$ , and we also show the equivalence with...     

Experimental demonstration of tunable multiple optical orthogonal codes sequences-based optical label for optical packets switching

In this paper, the tunable multiple optical orthogonal codes sequences (MOOCS)-based optical label for optical packet switching (OPS) (MOOCS-OPS) is experimentally demonstrated for the first time. The tunable MOOCS-based optical label is performed by using fiber Bragg grating (FBG)-based optical en/decoders group and optical switches configured by using Field Programmable Gate Array (FPGA), and the optical label is erased by using Semiconductor Optical Amplifier (SOA). Some waveforms of the MOOCS-based optical label, optical packet including the MOOCS-based optical label and the payloads are obtained, the switching control mechanism and the switching matrix are discussed, the bit error rate (BER) performance of this system is also studied. These experimental results show that the tunable MOOCS-OPS scheme is effective.     

Parameterizing both path amplitude and delay variations of underwater acoustic channels for block decoding of orthogonal frequency division multiplexing

There are no commonly-agreed mathematical models for the input-output relationship of underwater acoustic channels. For each path in a time-varying multipath channel within a short period of time (e.g., one short data block), this paper proposes to use one polynomial to approximate the amplitude variation and another polynomial up to the first order to approximate the delay variation within a block duration. Under such a channel parameterization, the discrete-time channel input- output relationship tailored to zero-padded orthogonal-frequency-division-multiplexing (OFDM) transmissions is then derived, based on which an OFDM receiver is validated using experimental data collected during the 2008 Surface Processes and Acoustic Communications Experiment. For channels with a short coherence time, the numerical results show that incorporating both the amplitude and delay variations improves the system performance.     

一种严格最佳(ν,k,1)光正交码的设计方法

介绍了严格最佳和准最佳(ν,k,1)光正交码的定义，阐述了它们与(ν,k,1)循环差集族的关系。基于Wilson均匀分布差引理和初等数论的基本理论，提出一种最佳(ν,k,1)循环差集族的构造方法，即构造定义在ν阶有限域上满足特定约束条件的k元集合。将该方法用于光正交码的设计中，可以有效地设计一些严格最佳(ν,k,1)光正交码，其中，码长ν为素数，码重k的取值为4、5和6。最后结合具体实例，给出严格最佳(ν,k,1)光正交码的计算机辅助设计方法。同其他设计方法相比，该设计方法既简单又实用，尤其对严格最佳（ν,k,1）光正交码而言，设计效率较高；随着码重k的增加，码的设计效率逐渐降低。     

Design of strict optical orthogonal codes with nonconstant weights for use in optical code-division multiplexing multimedia systems

We report the design of a new family of strict optical orthogonal codes (SOOCs) that permit the use of nonconstant code weights in optical code-division multiplexing (OCDM) systems. Because this new code can possess any number of pulses (i.e., 1s) in each codeword while still maintaining the minimum autocorrelation and cross-correlation constraints (i.e., “1”) for incoherent optical processing, its use can flexibly support multimedia applications in an OCDM system to meet varieties of transmission performance and traffic requirements which are demanded by different types of communication services. The method of designing the proposed codes is presented, and the bound on code length is also given.     

A high efficiency construction method of multilength optical orthogonal codes with correlation constraint two for OCDMA multimedia network

In order to construct multilength optical orthogonal codes (ML OOCs) with correlation constraint 2 for multi-rate OCDMA passive optical networks, a high efficiency construction method is presented. The main idea is to construct high efficiency mapping sequences to map optimal short length OOCs with cross correlation 2 into long length OOCs with cross correlation 2. Fundamental of constructing high efficiency mapping sequence is derived, and the mapping sequences based on multiplication table of integer domain is examined. Simulations based on the method show that the cardinality of long length OOCs is just slightly lower than Johnson bound. Therefore, it has very high variable length efficiency.     

Bound states of three and four resonantly interacting particles

We present an exact diagrammatic approach for the problem of dimer-dimer scattering in 3D for dimers being a resonance bound state of two fermions in a spin-singlet state, with corresponding scattering length a _F . Applying this approach to the calculation of the dimmer-dimer scattering length a _B , we recover exactly the already known result a _B = 0.6 a _F . We use the developed approach to obtain new results in 2D for fermions and bosons. Namely, we calculate bound state energies for three bbb and four bbbb resonantly interacting bosons in 2D. For the case of resonance interaction between fermions and bosons, we exactly calculate bound state energies of the following complexes: two bosons plus one fermion bbf, two bosons plus two fermions bf↑bf↓, and three bosons plus one fermion bbbf.     

Mechanical impedances distributed at the fingers and palm of the human hand in three orthogonal directions

The objective of this study is to investigate the basic characteristics of the three axis mechanical impedances distributed at the fingers and palm of the hand subjected to vibrations along three orthogonal directions (x_h, y_h, and z_h). Seven subjects participated in the experiment on a novel three-dimensional (3-D) hand–arm vibration test system equipped with a 3-D instrumented handle. The total impedance of the entire hand–arm system was obtained by performing a sum of the distributed impedances. Two major resonances were observed in the impedance data in each direction. For the hand forces (30 N grip and 50 N push) and body postures applied in this study, the first resonance was in the range of 20–40 Hz, and it was primarily observed in the impedance at the palm. The second resonance was generally observed in the impedance at the fingers, while the resonance frequency varied greatly with the subject and vibration direction, ranging from 100 to 200 Hz in the x_h direction, 60 to 120 Hz in the y_h direction, and 160 to 300 Hz in the z_h direction. The impedance at the palm was greater than that at the fingers below a certain frequency in the range of 50–100 Hz, depending on the vibration direction. At higher frequencies, however, the impedance magnitude at the fingers either approached or exceeded that at the palm. The impedance in the z_h direction was generally higher than those in the other directions, but it became comparable with that in the x_h direction at frequencies above 250 Hz, while the impedance in the y_h direction was the lowest. The frequency dependencies of the vibration power absorptions for the entire hand–arm system in the three directions were different, but their basic trends were similar to that of the frequency weighting defined in the current ISO standard. The implications of the results are discussed.     

Scaling properties of eden clusters in three and four dimensions

We study the scaling properties of noise reduced Eden clusters in three and four dimensions for variant B in the strip geometry. We find that the width W for large times behaves as a(s)g(L/s^d−1), where L is the width of the strip, s the noise reduction parameter, d the dimension of space, and a(s) a decreasing function of s, g is a scaling function with the property g(u)→1/2 as u→0 and g(u)u^x as u→∞, where χ is the roughness exponent. This scaling result leads to a new way of determining χ. In 3 dimensions, our numerical values for χ support a recent conjecture by Kim and Kosterlitz: χ = 2/(d + 2), and contradict all the former analytical conjectures. In 4 dimensions, we cannot distinguish between the conjectures of Kim and Kosterlitz and the conjecture of Wolf and Kertész, because large crossovers and finite size effects make the measurement of the exponents difficult.