住宅室内照明设计的探讨

结合建筑美学理念,提出了室内住宅照明设计的步骤,介绍了不同功能房间的设计要点,并提供了多种室内照具的选择方案,探讨了住宅室内照明控制的问题。     

异形柱双偏压正截面承载力的统一算法

首先根据异形截面双向偏心柱正截面承载力相关曲线的特点,采用曲线拟合方法,构造出一个可以表达各种异形截面柱"真实相关曲线"的相关方程——近似相关方程.然后,利用该方程作为承载能力约束方程,建立了异形截面钢筋砼双向偏压柱正截面承载能力的统一计算方法——相关方程法.该方法计算简便,公式统一且具有很高的计算精度,便于工程应用.     

不等时距灰色预测模型

提出了一种不等时距灰色预测ＧＭ（１，１）模型的方法，弥补了等时距ＧＭ（１，１）模型的不足，通过诸多的实例分析，结果理想可靠，有较好的实际意义。     

基于二次跳时序列的UWB无线电通信系统性能

讨论了扩展二次跳时序列和一般二次跳时序列及其特殊形式序列的构造，比较了它们的汉明互相关特性．在此基础上，比较了在PPM调制方式下基于这几类二次跳时序列的UWB系统的误码率，并给出了数值结果．研究结果表明，这几类二次跳时序列系统误码率相当一致，但一般二次跳时序列集具有更多的序列数目．     

A Concatenated ML Decoder for ST／SFBC-OFDM Systems in Double Selective Fading Channels

This paper presented a concatenated maximum-likelihood (ML) decoder for space-time/space-frequency block coded orthogonal frequency diversion multiplexing (ST/SFBC-OFDM) systems in double selective fading channels. The proposed decoder first detects space-time or space-frequency codeword elements separately. Then,according to the coarsely estimated codeword elements, the ML decoding is performed in a smaller constellation element set to searching final codeword. It is proved that the proposed decoder has optimal performances if and only if subchannels are constant during a codeword interval. The simulation results show that the performances of proposed decoder is close to that of the optimal ML decoder in severe Doppler and delay spread channels. However,the complexity of proposed decoder is much lower than that of the optimal ML decoder.     

Research and Development of a New Calibration Tool for Electronically Controlled Engine Based on KWP2000

Today‘s vehicles use electronic control units (ECU) to control engine/transmission, body and other amenities. All the vehicle performance depends on a lot of physical values and influence factors. This leads to a large number of control and regulation parameters in the ECU software. The ultimate objective of calibration work is the optimum determination of these parameters. Qualitatively excellent results can only be achieved in a shorter time by using a highly efficient calibration system. This paper provided an overview of a new calibration tool based on KWP2000 and gave an example calibration with this tool.     

汽车空调维护要点

汽车空调系统一般应注意以下维护要点：压缩机：压缩机的安装支架不得松动。传动皮带松紧度要适宜，过松会引起打滑，造成压缩机转速下降，制冷量不足；过紧又加剧皮带磨损以及造成曲轴轴承过早损伤。压缩机冷冻机油油面高度应在规定范围内，在正静情况下冷冻机油消耗量极少，如果从压缩机的视油镜片中看不到冷冻机油，则说明冷气系统中存在泄漏现象，应及时维修。     

Closed Loop Space-Time Block Coding for Wireless Downlink Transmission

In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments.     

STC-OFDM系统的post-IDFT多波束形成技术

提出了适用于空时编码-正交频分复用(OFDM)系统的后-逆离散傅立叶变换(post-IDFT)多波束形成技术.该技术通过对空频信道相关矩阵进行特征分解获得多个特征模式,再利用空时分组码(STBC)各发射分支信号的正交性使OFDM系统形成多个post-IDFT波束.接收端根据STBC传输矩阵的正交性对多波束解码.系统获得的空间分集增益为空频信道相关矩阵的特征值之和,最大空间分集增益与子载波波束形成方案相同,误码率比STC-OFDM的低.该技术将复杂度降低到子载波波束形成方案的1/S(S为OFDM系统的子载波数目),而且当波束维数(m)小于发射天线数目(M)时,可进一步减少M-m个IDFT模块     

灰色区间预测的新方法

针对具有离散程序大且总体趋势增长的一类序列，给出了一种灰色区间预测的新方法，该方法是先讨论序列的级比，对级比选取一些不同的阈值，根据不同的阈值对原始数据列进行分组，然后对各个分组序分别建立非等时距的灰色模型，由模型的解得出原始序列的预测值范围。