Can Markov regime-switching models improve power-price forecasts? Evidence from German daily power prices

Non-linear autoregressive Markov regime-switching models are intuitive. Time-series approaches for the modelling of electricity spot prices are frequently proposed. In this paper, such models are compared with an ordinary linear autoregressive model with regard to their forecast performances. The study is carried out using German daily spot-prices from the European Energy Exchange in Leipzig. Four non-linear models are used for the forecast study. The results of the study suggest that Markov regime-switching models provide better forecasts than linear models.     

Hydrogen energy from coupled waste gasification and cement production—a thermochemical concept study

A plant concept for hydrogen production from waste gasification coupled with cement manufacturing is presented. Hot precalcined cement meal, from the operating cement process, is used as heat carrier to provide energy required by the parallel arranged gasifier. The amount of CaO present in the cement meal operates simultaneously as an effective in situ _CO2${\mathrm{CO}}_2$-sorbent. First, a practical case study was devised to be able to perform simulations for estimation of expected hydrogen yield. The influence of different operation parameters of the gasifier and the hydrogen separation unit (steam-to-fuel ratio, pyrolysis temperature, PSA efficiency) was studied based on chemical equilibrium calculations. The simulation results indicate, that the coupling provides advantages for both processes. The production of a hydrogen-rich gas via thermal gasification benefits from the continuously available fresh CaO, which improves fuel conversion reactions and captures _CO2${\mathrm{CO}}_2$ in situ. High-calorific streams from gasification process remaining after hydrogen separation may substitute fossil fuels needed for cement process. For a steam/fuel ratio of 0.3 and a PSA efficiency of 0.7, the calculated hydrogen energy yield is 46% of fuel energy input.     

基于L1-范数的最大间距准则

在进行线性投影降维时,由于传统的最大间距准则(Maximum Margin Criterion,MMC)算法基于L2-范数,易于受到野值(outliers)及噪声的影响.该文提出一种基于L1-范数的最大间距准则(L1-norm-based MMC,MMC-L1)降维方法,它充分利用L1-范数对野值及噪声的强鲁棒性以及最大间距准则,提出了一种快速迭代优化算法,并给出了其单调收敛到局部最优的证明.在多个图像数据库上的实验验证了该方法的鲁棒性与高效性.     

基于ATmega16的远程温差循环控制器设计

设计一款基于ATmega16单片机的远程温差循环控制器。控制器分为主机和从机两部分,两者通过RS 485通信,距离可以达到1 000 m以上。从机采用热敏电阻作为测温元件,使用ATmega16单片机内置的A/D转换模块实现多路温度的模/数转换输入和测量,并把测量数据发送给主机,而且完成相应的控制动作;主机使用ATmega16单片机完成基本功能的设置,接收从机数据并用LCD显示相关工作状态和设置参数。在此,对主从机、RS 485通信电路、测温电路和继电器控制电路等主要技术做了详细分析。     

基于nRF24L01的无线温度采集系统设计

介绍一种由nRF24L01型无线数据传输器和高精度的单总线数字温度传感器DS18B20组成的无线数据传输系统;详细阐述该系统的硬件和软件设计要点;给出基于STC12LE5408设计的nRF24L01硬件接口电路和程序代码;并讨论该系统在无线温度采集系统中的应用。     

基于AVR单片机的汽车尾气检测系统设计

针对当前汽车尾气污染加重和检测标准日益完善的现状,为了弥补传统汽车尾气检测系统在测量精度、稳定性、人机操作等方面存在的不足,提出了一种基于AVR单片机的汽车尾气检测系统设计方案。系统以ATMEGA8L为核心控制器,主要由传感器模块、信号采集调理电路、A/D转换器以及显示模块等组成。实验结果表明,系统具有测量精度高、稳定可靠、人机交互性好等优点。     

基于ARM嵌入式的视频监控系统的设计

提出一种基于ARM嵌入式开发平台视频监控的实现方案。通过V4L2在Linux下构建视频图像采集和显示,然后使用servfox和spcaview构建视频服务器,系统可在Linux和Windows操作系统下通过窗口或者网页进行视频监控和图像抓拍。测试表明系统的监控图像清晰,并具有体积小、成本低、可靠性强等优点。     

改进的16进制正交幅度调制码的相位估计算法

相干光通信系统中的相位恢复是克服信号收发端和传输过程中产生的相位噪声的必要步骤。为获得低的运算复杂度和良好的相位估计效果,本文对传统的四次方相位估计算法进行了改进,使之具有自适应的数据块长度控制功能。通过理论分析以及Matlab数值仿真方法验证改进的效果。对于16进制正交幅度调制码（16QAM）,改进后的算法在几乎不增...     

带有显示功能的锂电池和镍铬电池充电系统

系统以PIC16F873单片机和LTC4002锂电池充电芯片为核心,针对不同电池特性,采用不同的充电方式,可以对目前广泛使用的锂电池和镍铬电池充电,同时具有实时显示充电及放电电流、电池电压,容量统计和电池特性等功能,实现了符合铁道部所有相关规范的列车尾部保护装置的充电系统。     

水稻花后衰退珠心和胚乳发育初期Ca2+的超微细胞化学定位

应用焦锑酸盐沉淀技术对水稻花后衰退珠心和胚乳发育初期进行了Ca^2 的超微细胞化学定位。结果显示在初始衰退的珠心细胞中Ca^2 主要分布于液泡膜上和核内；在衰退中期的珠心细胞中，Ca^ 主要分布在核膜、液泡膜及质膜上；在严重衰退的珠心细胞，Ca^2 仅存在于液泡中。珠心降解的Ca^2 跨过胚囊壁，通过质外体向胚乳内运输；发育初期的胚乳细胞，Ca^2 主要位于胞间隙，线粒体和液泡中也有少量分布。讨论了Ca^2 与珠心PCD的关系。