Transform domain technique for windowing the DCT and DST

In this paper, an algorithm is developed to apply Hann, Hamming, Blackman and related windows directly in the transform domain for the discrete cosine transform and discrete sine transform. These algorithms are useful in applications where windowing is required in order to minimize edge effects caused by implicit symmetries in the transform domain that are not replicated in the real-world data. Examples of such applications include data communication, adaptive system identification and filtering, real-time analysis of financial market data, etc. Software implementations in C language are also given.     

基于数控加工应用的非圆曲线方程

在数控加工中经常有由一些复杂曲线构成的非圆曲线（如椭圆、抛物线、双曲线、正余弦曲线以及拟合曲线等）工件,在各级的数控技能大赛中也有应用。本文介绍基于数控车/数控铣和加工中心应用的非圆曲线方程的各种形式。     

Utilization of discrete transforms to conquer the problems of multi-tone systems

This paper presents a new implementation of discrete multi-tone (DMT) systems based on different discrete transforms that include the discrete sine transform (DST), discrete cosine transform (DCT), and discrete wavelet transform (DWT). The implementation also considers time-domain equalization to mitigate channel distortion. Compared to the fast Fourier transform discrete multi-tone (FFT-DMT) system, the proposed implementations have an advantage in that their energy-compaction property helps in reducing the channel effects. The performance of the DST-DMT, DCT-DMT, DWT-DMT, and FFT-DMT systems, employing a time-domain equalizer (TEQ), is investigated in the paper. It has been demonstrated by computer simulations that the proposed implementations outperform the FFT-DMT system and that the utilization of the TEQ can lead to higher bit rates     

Determination of feeding rate ratio in coupled fed-batch fermentation with pH feedback considering limited number of switches

This paper focuses on binary optimal control of fed-batch fermentation of glycerol by Klebsiella pneumoniaewith pH feedback considering limited number of switches. To maximize the concentration of 1,3-propanediol at terminal time, we propose a binary optimal control problem subjected to time-coupled combinatorial constraint with the ratio of feeding rate of glycerol to that of NaOH as control variables. Based on time-scaling transformation and discretization, the binary optimal control problem is first transformed into a mixed binary parameter optimization problem consisting of not only continuous variables but also binary variables, which is then divided into two subproblems via combinatorial integral approximation decomposition. Finally, a novel fruit fly optimizer with modified sine cosine algorithm and adaptive maximum dwell rounding are applied to solve the obtained subproblems numerically. Numerical results show the rationality and feasibility of the proposed method.     

基于经验模态分解的中国生态足迹与生态承载力动力学预测

利用mathcad2001和matlab6.5软件,计算了中国1961年～2005年生态足迹和生态承载力,通过经验模态分解（EMD）方法对其进行分析,在此基础上,建立动力学模型对其未来进行预测,希望能通过对中国生态足迹动态研究,建立一个带有周期波动的动力学预测模型,为研究长时间序列的动态变化提供一个全新的研究方法。通过EMD分析后我们可以得到研究要素的不同时间尺度的演化曲线,将这些曲线看成是系统在不同时间尺度下的特解,则可以根据不同时间尺度的EMD分量的曲线够建起对应的动力模型,如趋势项一般对应于指数或线形动力方程,大尺度的周期分量一般可以对应于正弦或与余弦形式的动力方程,最后我们建立一个总的动力预测模型。研究结果表明：随着生态足迹的增大和生态承载力的减小,中国未来20年的生态赤字越来越大,由2006年的-0.932到2025年的-1.632,接近2倍,发展处于不可持续状态。经验模态分解（EMD）方法能很好的分解出生态足迹和生态承载力的波动周期,符合它们的发展规律,并用动力学预测了它们的发展态势,经拟合表明,预测的结果与实际值误差较小。这说明基于EMD的动力学预测模型是科学的。     

一种新的改进Patchwork算法的彩色数字水印研究

本文提出了一种将彩色数字水印嵌入到彩色载体图像的新算法,利用改进的Patchwork方法将一级小波分解的水印图像的低频部分分别四次嵌入到经过离散余弦变换和离散小波变换后的载体图像的RGB分量中,提取的时候,将四次嵌入的低频分量取出并求平均值,用来作为水印的最终低频分量。经过实验验证,该算法对很多攻击具有很好的鲁棒性。     

Enhancing sparrow search algorithm via multi-strategies for continuous optimization problems

As a recent swarm intelligence optimization algorithm, sparrow search algorithm (SSA) is widely adopted in many real-world problems. However, the solutions to the limitations of SSA (such as low accuracy of convergence and tendency of trapping into local optimum) are still not available. To address these issues, we propose an enhanced multi-strategies sparrow search algorithm (EMSSA) based on three strategies specifically addressing the limitations of SSA: 1) in the uniformity-diversification orientation strategy, we propose an adaptive-tent chaos theory to allow more diversity and greater randomness in the initial population; 2) in the hazard-aware transfer strategy, we construct a weighted sine and cosine algorithm based on the growth function to avoid trapping into the state of local optima stagnation; 3) in the dynamic evolutionary strategy, we design the similar perturbation function and introduce the triangle similarity theory to improve the exploration capability. The performance of EMSSA in solving the continuous optimization problems about the 23 benchmark functions, CEC2014, and CEC2017 problems is much improved than that of SSA and other state-of-the-art algorithms. Furthermore, the results of the density peak clustering optimization show that the EMSSA outperforms SSA.     

General 9-instant discrete-time Zhang neural network for time-dependent applications

Zhang neural network (ZNN) is widely applied to solving time-dependent problems. For the sake of the implementation on the digital hardware platform, ZNN models need to be discretized. In this paper, as a further study of Zhang et al. discretization (ZeaD) formulas, a novel general 9-instant ZeaD formula is presented, and clear constraints are firstly given with proof. To evaluate the presented 9-instant ZeaD formula, three continuous-time models for time-dependent matrix inversion and pseudoinversion are presented with the help of Getz-Marsden dynamic system (GMDS) and ZNN. Then the corresponding discrete-time models are obtained by using the 9-instant ZeaD formula. According to the comparison experiments, the 9-instant ZeaD formula is substantiated to be effective and consistent with the theory. Furthermore, the problem of mobile angle-of-arrival (AoA) localization is investigated as a more specific and practical problem. In order to overcome the singularity problem of the tangent function in the representation of the AoA localization system, a new representation with sine and cosine functions is presented. Similarly, the continuous-time model is derived and discretized. Through comparison experiments, the discrete-time model obtained by the 9-instant ZeaD formula achieves desirable results, which further show the efficacy of the 9-instant ZeaD formula.     

基于FPGA的数控移相正弦信号发生器的设计

本文介绍了基于FPGA技术,利用VHDL编程并加以简单的外围电路构成的数控移相正弦信号发生器。具体应用FPGA芯片及D/A转换器,采用直接数字频率合成技术(DDS),设计实现了一个频率、相位可控的正弦信号发生器。采用此方法设计的数控移相正弦信号发生器能够产生频率、相位均可数字式预置并可调节的两路正弦波信号,频率范围为20Hz至20kHz,相位差范围为0-359°,步进为1°。     

基于熵的项目组合配置协同度研究

以熵为理论出发点,在定义正协同、负协同、模糊协同和协同度等概念的基础上,提出定量描述项目级、工序级配置组件协同关系矩阵,设计以阶段协同熵加权反映配置组件模糊协同关系、以组件内外协同关系之和度量项目组合配置组件协同度的分析方法,构建基于熵的项目组合配置协同度决策模型,并通过企业实践对模型的可操作性进行验证。     

Noise variance measurement with presence of strong sine burst interference

A novel method of noise variance measurement in the presence of strong sine burst interference with unknown parameters is presented. The measurement system is based on the Adaptive Sine Pulse Shortener (ASPS) which shorts each sine pulse from which the interfering burst is composed. After this a conventional noise variance measurement method is applied. A measurement accuracy is satisfactory when the interfering signal is strong and the number of periods of interfering sine-wave in each sine pulse is great. While a practical implementation of the proposed procedure is not simple in hardware, the microprocessor implementation is quite realizable.     

基于向量相似度的招聘就业双向推荐模型

分析了当前国内就业形势,针对当前“招工难”与“就业难”问题并存的现状,提出了一个基于向量相似度的招聘就业双向推荐模型.模型首先按条件对候选推荐信息进行筛选;然后将招聘和求职信息转化为向量,为不同分量建立相应的量化规则并进行量化,使之可计算;最后采用夹角余弦公式计算向量间的相似度,并以此作为双向推荐的标准.模型在测试数据集和实际数据集上均取得了较好的运行效率,准确率高,达到了最优化推荐,一定程度上缓解了江门市目前招聘就业困难的压力,取得了良好的社会效益.     

基于视频压缩编码的动态图像水印方案

提出了一种新的基于视频压缩编码的动态图像水印方案。在嵌入水印时,充分考虑动态图像压缩编码的特性,对帧内编码帧(I帧),将水印信息嵌入到DCT低频系数中;而对帧间编码帧(P,B帧),结合动态补偿/离散余弦变换(MC/DCT)混介编码,把水印信息嵌入到运动补偿后的残差图像的自流成分中。同时,在水印嵌入时,采用扩频技术与多维水印相结合的方法,并通过相关检测的方法判断水印的存在。由于水印的检测是对视频码流直接实施的,不需要对压缩数据进行完全解码,从而大大降低了计算量,提高了视频数据水印的适用性。     

基于云计算的余弦向量度量法文本检索模型

针对云计算平台下信息检索的特性,在对经典余弦向量度量法文本检索模型(CCVMMTR模型)局限性进行分析的基础上,提出按查询索引项在文本不同检索范围设置不同权值计算方法的基于云计算的余弦向量度量法文本检索模型(CVMMTRCC模型),通过模拟实验对CCVMMTR模型与CVMMTRCC模型下文本与查询相似度计算结果进行对比,说明云计算平台下CVMMTRCC模型的检索效率能更好地反映用户的需求。     

两种相似度计算方法对KNN分类效果的影响研究

KNN最邻近算法是文本自动分类中最基本且常用的算法,该算法中需要计算文本之间的相似度.以Jensen-Shannon散度为例,在推导和说明其基本原理的基础之上,将其用于计算文本之间的相似度;作为对比,也使用常规的余弦值方法计算文本之间的相似度,并进而使用KNN最邻近算法对文本进行分类,以探讨不同的相似度计算方法对使用KNN最邻近算法进行文本自动分类效果的影响.多种试验材料的实证研究说明,较之于余弦值方法,基于Jensen-Shannon散度计算文本相似度的自动分类会使分类正确率更高,但会花费更长的时间.     

变异系数加权的组合赋权模型及科技评价实证

通过R聚类剔除反映信息重复的指标,利用因子分析遴选对科技评价影响较大的指标,构建了能够反映科学发展观内涵的科技评价指标体系。在此基础上,利用变异系数对主观G1权重、客观余弦夹角权重进行组合加权,建立了基于变异系数加权的组合赋权模型,并对中国14个典型的省份科技评价数据进行了实证。创新与特色:一是通过变异系数对主观G1权重、客观余弦夹角权重进行加权,构建了变异系数加权后组合权重最大的目标函数,进而确定了主、客观权重的组合系数θ_1、θ_2,反映了组合赋权中主、客观权重分布变异性越大、权重越大的赋权思路。弥补了现有组合赋权中主、客观权系数相等,无法有效反映专家知识经验和客观数据差异的不足。二是实证研究表明:科技投入不足是制约江西、广西两省科技发展较差的主要因素;科技对经济与社会的影响偏弱是制约四川省科技发展的关键因素;科技产出不足是制约黑龙江、山东、河南三省科技发展的瓶颈因素。     

DCT-BP神经网络在表情识别中的应用

人脸表情识别作为智能化人机交互技术中的一个重要组成部分,近年来得到了广泛关注。本文提出了一种用DCT-BP神经网络算法来识别面部表情,先对图像进行灰度均衡和图像平滑的预处理,然后利用离散余弦变换获取图像的表情特征参数,最后利用前向反馈算法进行识别。     

C余弦函数的表示定理

文章利用了积分半群和C余弦函数之间的关系,得到了三个不同形式的余弦函数的表示定理.     

科技进步与经济增长的分配理论——对十五个国家的测算

把新增长理论与新制度经济学的合理思想与方法结合起来，对国内生产总值与知识、劳动力、固定资产等生产要素、制度因素及环境外部性的关系进行理论分析，提出经济增长的分配理论，建立起经济增长的新模型，通过对十五个国家的实证测算证明经济增长分配理论的正确性，并得出八点结论。     

单相逆变器电源的研制

介绍了单相正弦脉宽调制逆变器的工作原理和利用集成脉宽调制器SG3525产生SPWM波的方法，给出了样机实验的结果。