基于自适应神经网络的光伏输出功率预测

文中提出了一种基于不同拓扑结构的自适应神经网络(ANN)预测光伏输出功率的方法,建立了一个与数据采集系统协同工作的天气监测系统,利用三种不同类型的自适应神经网络进行功率输出预测。为了研究气候变化对发电量的影响,使用天气数据(气温、太阳辐照度和风速)以及两个测试光伏电池板历史功率输出数据对ANN进行了训练。通过将模型预测值与功率输出测量数据进行比较,计算结果验证了所提方法对短期功率输出预测问题的适用性,并确定了最佳拓扑结构。     

基于PL3200的CDMA扩频电力线载波通信系统设计

介绍CDMA扩频通信的基本原理、PL3200型SoC的结构及其载波通信功能模块,提出一种基于PL3200的CDMA扩频电力线载波通信系统的设计方案.     

Novel spatial spread spectrum based fiber optic CDMA networks forimage transmission

Novel code division multiple access (CDMA) fiber optic networks based on spatial frequency spread spectrum for image transmissions are proposed. Two key technologies are the parallel fiber optic transmission of spatially encoded images and parallel access to image data through optical spatial encoding and decoding. The temporal signature sequences used in conventional time-domain CDMA are replaced by two-dimensional (2-D) signature patterns to encode and decode binary image pixels. This enables the fully parallel access and transmission of images. The fundamental rules and methodology to construct optical orthogonal signature patterns (OOSP) are presented. Furthermore, it is shown that the all-optical implementation of the proposed system is feasible by utilizing optically addressable spatial light modulators in both the spatial encoder and the decoder along with multicore fibers as the parallel image transmission medium. The predicted overall throughput can reach 10 Tb/s     

基于MLP神经网络的铝电解槽出铝量预测

铝电解生产是一个大延迟、多变量耦合和非线性的过程.铝电解槽每天的出铝量往往是根据多年积累的经验制定的,目前为止还没有一个准确的计算方案.根据电解槽的各个状态参数进行相关性分析,其中电解质水平、铝水平、槽温、分子比变化等一些列参数对出铝量的影响相对较大.本文将从操控系统得到的各参数数据集分为测试集、训练集,利用机器学习框架搭建MLP神经网络日出铝量模型,通过模型得到预测值和真实值进行对比,对误差曲线进行了分析.     

基于CPLD的功率输出自测试及保护技术研究

机载供电系统中存在大量的功率接触器和继电器,在驱动这些装置时,如果电路中的瞬态电流过大,将损坏机载计算机本身及后级控制电路.本文设计并实现了一种基于CPLD的功率输出自测试及短路保护技术,由硬件分立元器件和可编程逻辑器件代替DSP处理器,无需软件参与,完全由硬件实现功率驱动和过流保护,使其具有非常高的可靠性和安全性,性能大大优于传统控制开关.     

基于OFDM的多载波CDMA系统的研究

MC—CDNA系统是将CDNA和OFDM技术的优点结合在一起的多址方案。首先介绍了OFDM的基本原理，并据此给出MC—CDNA系统的模型，通过对MC—CDNA和DS—CDNA的性能比较，MC—CDNA能提供更高的系统容量，结构更简单，抗干扰性更强，更适用于未来移动通信的需要。     

Synchronous CDMA based on the cyclical translations of a CAZAC sequence

A new scheme of synchronous CDMA is introduced in the paper. The new scheme is based on a code made by all the cyclical translations of a basic sequence having constant amplitude and white discrete spectrum. Such a code is proposed here for the first time as a code for CDMA. According to the proposed scheme, a cyclic prefix is appended to the multiplexed signal. The proposed scheme has a property that none of the known CDMA schemes has: in a multipath environment, it allows multiuser interference to become cyclic intersymbol interference. Noticeably, the memory of the finite state machine that describes the ISI model is equal to memory of the multipath channel. The main advantage of our proposed scheme is that optimal and suboptimal detectors can be obtained from detectors proposed in the past for the ISI channel, which are much easier to implement than conventional multiuser detectors of classical CDMA schemes. Another advantage of our scheme is that it leads naturally to a signal processing architecture similar to that of OFDM systems, hence based on the efficient FFT/IFFT algorithm.     

An analytic approach for CDMA output of feedforward power amplifier

In this paper, a novel method is introduced to predict the Code-Division Multiple-Access (CDMA) output spectrum of an RF power amplifier linearized with feedforward technique based on transfer function. In this method, an RF power amplifier is modeled mathematically by nonlinear complex envelope transfer function based on AM-AM and AM-PM distortion diagrams. Using this model, analytic expressions of CDMA output spectrum of power amplifier is calculated. Having mathematical model of RF power amplifier leads to derive analytic expressions for InterModulation (IM) products in feedforward amplifier. Based on these expressions, IM products are related to nonlinear complex envelope transfer function of feedforward amplifier. Then, CDMA output spectrum of feedforward linearization technique is predicted. The loops imbalances in feedforward technique are considered in analysis. Finally, the results of derived expressions in MATLAB software are compared with ADS simulations results and good agreements were achieved. Employing this method gives insight for feedforward analysis and loops imbalances effects in feedforward amplifier for CDMA applications.     

CDMA蜂窝网频谱规划方案的比较分析

本文建议了CDMA蜂窝网频谱规划的两种方案,频率复用系数分别为K=4/3与K=3.文中以纯语音业务为例讨论了不同频谱规划之间的区别.仿真结果显示目前所普遍采用的K=4/3的频谱规划方案并非最佳选择,当小区之间移动终端分布不均匀时,K=3的频谱规划方案在小区容量方面优于K=4/3的规划方案.     

基于视觉掩盖的码分多址水印算法

本文提出了基于视觉掩盖的的码分多址水印算法,利用视觉掩盖在小波变换域完成水印的嵌入.采用水印估计的方法提取水印信号,实现了不需要原始图像完全恢复出水印信号的水印盲检测,进一步提高了数字产品版权认定的可靠性.     

CO激光器的输出频谱特性

本文报导了CO激光器的输出频谱特性，指出CO激光谱线是单纵模，调谐腔长，振荡频率在增益剖面上扫描，调谐范围为C/2L。     

DCT域的数字指纹CDMA扩频追踪

以DCT变换为基础,结合了数字图像JPEG压缩和通信CDMA技术的特点,提出了一种基于双DCT变换、扩频技术的二维数字指纹追踪算法。通过像素值和DCT系数两种平均合谋方式攻击和追踪性能分析验证,该追踪方案能够有效抵抗多用户合谋和抗JPEG压缩,同时具有较高的峰值信噪比和良好的追踪特性。     

Design of spread spectrum multicode CDMA transport architecture formultimedia services

We investigate a new application of the well-known spread spectrum code division multiple access (SS-CDMA) techniques to multimedia services related to the development of the next-generation wireless mobile networks interconnecting with a wireline ATM-based broadband network. Such services allow users to share novel multimedia applications without any geographical restrictions. However, since the mobile radio channel has a fixed limited bandwidth, the traditional SS-CDMA system may not be sufficient to accommodate the variable bit rate (VBR) multimedia services requested by multiple mobile users simultaneously. Moreover, the traffic load at the base station can change dynamically due to the time-varying throughput requirement of these requested multimedia services. To tackle this difficulty, a multicode CDMA (MC-CDMA) technique is proposed to provide multirate multimedia services by varying the number of spreading codes assigned to each user in order to meet its throughput requirement. In MC-CDMA, a spreading code can be used to transmit information at a basic bit rate. Users (video or data) who need higher transmission rates can use multiple codes in parallel. Meanwhile, the maximum available number of codes in the MC-CDMA system is still limited. Hence, a cost-effective dynamic code allocation scheme has then been proposed to dynamically assign an appropriate number of codes to each user for achieving the maximum resource utilization for multiuser multimedia services via the mobile radio channel. Finally, a number of real multimedia titles generated from the well-known MacroMind Director are conducted to evaluate performance     

Dynamic spectrum access based on interruptible spectrum leasing

Dynamic spectrum access (DSA) based on interruptible spectrum leasing allows secondary users (SUs) to lease a licensed, but idle, spectrum that is owned by primary users (PUs) on condition that the PUs preempt the access to the leased spectrum. This paper considers a DSA scenario where the SUs opportunistically use the primary spectrum in addition to their own band and the PUs use their own band regardless of the opportunistic access. This operating scenario can contribute to leverage the spectrum utilization by exploiting underutilized spectrum resources, but involves a problem that the SUs may be forced to interrupt on-going services in response to the PUs?? reclamation of the leased spectrum. In this paper, we address the optimal call admission control (CAC) problem in order to coordinate the DSA based on interruptible spectrum leasing by considering the tradeoff between the additional spectrum use and the penalty on the service interruption. To this end, we adopt the profit of the secondary wireless service provider as a cost function of the CAC policy in a market mechanism manner. The optimization problem is modeled as a profit maximization problem, and a linear programming (LP) formulation of the semi-Markov decision process approach is provided. Through the simulation results, we analyze the LP solution of the optimal CAC for the leasing based DSA and demonstrate that the proposed CAC policy judiciously uses the access opportunities of the SUs considering the service interruption.     

UMTS/IMT-2000 based on wideband CDMA

The UMTS terrestrial radio access is based on wideband 4.096 Mchip/s DS-CDMA technology. UTRA will be connected to an evolved GSM core network for both circuit and packet services. A merger between ETSI/Europe and ARIB/Japan based on W-CDMA, a GSM core network, and a common frequency allocation according to the ITU Recommendation of 2 GHz makes a global IMT-2000 standard feasible. UTRA based on W-CDMA fully supports the UMTS/IMT-2000 requirements (e.g., support of 384 kb/s for wide-area coverage and 2 Mb/s for local coverage). Furthermore, the air interface has flexible support of mixed services, variable-rate services, and an efficient packet mode. Key W-CDMA features also include improved basic capacity/coverage performance compared to second-generation systems, full support of adaptive antenna arrays, support of hierarchical cell structures with interfrequency handover, and support of asynchronous inter-base-station operation. There have been no constraints due to the strong requirements for backward compatibility with second-generation systems. This has facilitated a high degree of flexibility and a future-proof air interface. Extensive evaluations by means of simulations and field trials have been carried out by a number of companies, and full system tests are ongoing. Consequently, W-CDMA technology can now be regarded as a mature technology, ready to provide the basis for UMTS/IMT-2000     

基于CDMA2000的移动视频监控系统

随着计算机技术、微电子技术、通信技术不断创新和发展,在一定程度上极大地促进了嵌入式系统的发展。嵌入式系统已成为当今IT界最有发展前途的应用领域之一,该系统基于IntelSitsang开发平台,采用嵌入式Linux技术,利用cdma2000移动公网,实现远程实时移动视频监视功能,并可远程控制监视范围及方向。能用于交通、银行运钞车及突发事件现场报道等多种场合。在实现过程中考虑了GUI软件和PC机上软件的结构设计,文中给出上述系统的实现方法。     

On the output spectrum of unlocked driven oscillators

A method is given to determine the components of the signal of an unlocked driven oscillator. The phase modulation signal, which perturbs the free oscillation, is expanded in a Fourier series.     

基于CDMA的彩色图像数字水印算法的研究

CDMA是通信系统中一种有效的通信方式.水印信道与通信信道之间具有相似性,可以将CDMA引入数字水印技术中,利用CDMA技术在数字媒体中嵌入信息是一种实用、有效的方法.文章提出了基于CDMA原理的扩频数字水印的实现,采用Walsh码作为正交扩频序列.然后将水印信息嵌入到载体图像的DCT(离散小波变换)的中频系数中.实验表明该方法具有良好的不可见性和鲁棒性.     

基于软件无线电的CDMA系统中基站接收单元的实现

软件无线电由于其特有的结构通用、功能灵活、系统改进和升级方便等优点 ,成为未来移动通信发展的关键技术之一。CDMA技术则是未来第三代移动通信系统中首选的多址方式。本文以IS - 95标准为参考 ,探讨了在CDMA基站中引入软件无线电的优点 ,设计了基于软件无线电思想的CDMA基站接收单元的实现方案 ,并分析了基站接收单元的各个模块。     

CDMA基站射频指标的在线测试

无线电设备检测是各级无线电管理机构依据国家的有关法律、法规和具体规定，对无线电设备的质量实施的一种监督检查活动。无线电设备检测工作贯穿于无线电设备研制、生产到投入使用后的全过程。由于许多无线电设备（如微波站、公众移动通信网基站等）安装使用后不宜采取送检的方式实施检测，因此在线测试便成为无线电管理机构实施无线电设备检测的一项重要内容，也是为设台单位提供技术支持的重要手段。我们在2000年6月完成了对GSM基站的在线测试后，2001年10月—11月又对中国联通公司临沂分公司试运行的CDMA基站的射频指标进行了在线测…