基于DM642的光纤中心定位算法优化

大规模的数据存取是制约数字信号处理器系统效率的主要因素之一。在传像光纤束成像系统中,为提高出端光纤束在光纤中心定位过程中数据存取的效率,提出DM642平台下的光纤中心定位优化方法。在存储器配置方面,设置二级储存器缓存与片内随机存储器的模式,预取部分片外数据到片内随机存储器。在数据传输方面,设计数据存储动态偏移量,自适应迭代,避免重复读入。实验结果表明,优化后的算法实现了光纤中心的定位,时间开销降低了1/4,提高了系统的运行效率。     

一种基于VoIP的改进WSOLA丢包隐藏算法

丢包现象严重影响VoIP的通话语音质量。WSOLA(Waveform Similarity Based Overlap-Add)算法是一种基于接收端的丢包隐藏方法,可以较好地提高语音质量。在介绍WSOLA算法原理的基础上,针对该算法中计算互相关系数所需计算量较大,会增加过多计算延时的问题,提出一种互相关系数计算的改进方法。最后通过仿真对重建语音信号质量进行了对比。     

一种基于电容应变式传感器的信号调节电路

电容应变式传感器是一种结构型传感器,是依赖其结构参数的变化实现信息转换,将电容的变化转化为输出电压的变化。基于这一原理,利用虚拟电子仿真软件设计了电容式传感器信号调节电路,并进行应用仿真。通过仿真可以看出,输出电压的实际值与测量值的接近程度非常高,非线性误差很小,性能优越,灵敏度较高。     

市县级气象信息电话答询系统的集成与实现

气象信息电话答询系统是气象部门对外的一个重要窗口,它以电话语音播报形式把专业气象信息传送至千家万户。随着专业气象服务工作的深入开展,社会对气象信息的发布形式要求逐步提高,内容要求更加丰富,信息要求更加及时,系统要求更加稳定。分析市县级电话答询系统的技术特点,结合市县级实行节约化的实际情况,设计市县级气象信息电话答询系统,系统能够实现市县级气象信息电话语音的集中制作和快速传输、应答。该系统投入使用后运行状况良好,具有广泛的推广应用价值,对市县级气象信息电话答询系统的搭建设计有较好的借鉴作用。     

LTE系统基于传输分集的信号检测的DSP实现

信号检测是长期演进( LTE)系统接收端的一项重要技术,对系统的性能有着较大的影响。在LTE系统中,接收端的天线同时接收来自发送端的多个天线端口的数据,因此接收端必须采用信号检测算法还原发送端的数据。分析与研究了基于传输分集的信号检测算法,并着重讨论了空频编码法,提出了一种简单的DSP实现方案。该方案已成功应用于TD-LTE TTCN扩展测试集仪表开发项目中。     

基于FPGA的脉搏信号采集系统

基于中医诊脉客观化的需求,本文介绍了基于FPGA的脉搏信号采集系统,脉搏信号经过脉搏传感器转换为微弱的电信号,再经过信号调理电路,之后把调理电路输出的模拟信号送往A／D转换器进行模数转换,然后再送入FPGA进行相应的处理后籽数据显示在显示屏上,同时也将信号送入计算机进行进一步的分析和处理。经过现场测试,可较好的实现脉搏信号采集系统的功能,具有广阔的应用前景。     

遗传算法优化 BP 神经网络的信号检测

针对传统方法单独采用 BP 神经网络算法易陷入局部极值的问题,提出了遗传算法优化 BP 神经网络,并将其应用于 MIMO -OFDM系统信号检测中。该方法将遗传算法与神经网络相结合,用遗传算法优化神经网络初始值,使 BP 网络快速收敛到最优解,避免了由初始值的随机选取而带来的检测误码。仿真结果表明所提出的方法在误码率方面有比较好的性能。     

Jump neural network for online short-time prediction of blood glucose from continuous monitoring sensors and meal information

Several real-time short-term prediction methods, based on time-series modeling of past continuous glucose monitoring (CGM) sensor data have been proposed with the aim of allowing the patient, on the basis of predicted glucose concentration, to anticipate therapeutic decisions and improve therapy of type 1 diabetes. In this field, neural network (NN) approaches could improve prediction performance handling in their inputs additional information. In this contribution we propose a jump NN prediction algorithm (horizon 30 min) that exploits not only past CGM data but also ingested carbohydrates information. The NN is tuned on data of 10 type 1 diabetics and then assessed on 10 different subjects. Results show that predictions of glucose concentration are accurate and comparable to those obtained by a recently proposed NN approach (Zecchin et al. (2012) [26]) having higher structural and algorithmical complexity and requiring the patient to announce the meals. This strengthen the potential practical usefulness of the new jump NN approach.     

A fractal approach for interpretation of local instantaneous temperature signals around a horizontal heat transfer tube in a bubbling fluidized bed

Temperature signals measured around a horizontal heat transfer tube in a bubbling fluidized bed have been analyzed using Hurst's rescaled range (R/S) analysis. This analysis estimates and identifies long-term persistence or correlation in measured time series. The Hurst exponent H, which is evaluated from R/S analysis, also provides the local fractal dimension of the time series. A new approach to analyze an air fluidized particle system is proposed based on the evaluation of the Hurst exponent. Two Hurst exponents can be evaluated from a single time series, one from the discrete time fractional noise (where the linearity of the signal is subtracted and short-term fluctuations are emphasized) and the other from the signal itself (without subtracting the linearity of the signal). The authors argue that the Hurst exponent obtained from discrete time fractional noise characterizes the particle motion, whereas the Hurst exponent obtained from the signal itself characterizes the bubble motion. Moreover, a comparison between these two Hurst components identifies the zones where an alternating type of contact between the tube surface and the bubble-emulsion phase occur. The results were interpreted in conjunction with the mutual information function. The mutual information function provides the relationship between the data points separated in time and uses only the statistical relationship between the data points. The mutual information functions and the Hurst exponents exhibited similar trends around the heat transfer tube.     

无线MESH网络中基于可信度的VoIP安全机制

根据信任管理机制提出了一种基于可信度的动态模型,结合可信机制、贝叶斯定理、自适应机制和Beta分布,通过动态计算和更新结点的信任度值来识别和隔离恶意结点,最后通过对SIP协议的扩展对模型的性能进行仿真验证。仿真结果表明,提出的动态模型可以有效的提高恶意结点的识别和隔离率。