射频采样接收机中ADC的设计选型

本文介绍了ADC的性能指标和ADC器件选择的一般标准,并针对软件无线电中现有的射频采样接收机的模型,定量地分析了相应的ADC选择指标,并对相应模型的优劣进行了深入讨论。     

关于烟气在线监测装置SO2周期性异常的分析与处理

本文针对目前电厂脱硫烟气连续排放监测系统（CEMS）中SO2数据周期性波动,通过对历史数据曲线分析排查,发现取样探头温控仪故障导致取样探头加热器无法加热,烟气中水分遇冷凝结在管壁,管壁中的水分平时吸收烟气中的SO2,导致测量值偏低,待水珠汇聚变大流入下面带加热的取样管中后,水中溶解SO2的集中释放,导致数据在短期急剧上升,蒸发释放完后回归到原来的水平,形成这样一个周期性吸收和集中释放的过程。可见烟气取样管道温度保护环节在烟气测量中的作用非常重要。     

基于FPGA的A/D转换采集控制模块设计

采用FPGA器件EP1C3T144C8N处理器,对A/D转换芯片AD7714进行采样控制.整个设计在Quartus I平台下进行软件编程,采用Verilog语言描述,实现正确的AD7714转换的工作时序控制过程,并将采样的数据存储起来进行处理.本设计可用于微弱信号采集和实时监控方面,仿真结果显示该模块工作性能稳定、可靠性高、使用方便.     

基于ADC的TR-UWB数字接收机性能及其FPGA实现

发送参考超宽带(Transmitled reference UWB,TR-UWB)系统采用自相关接收检测技术作为一种非最优接收机,不需要进行信道估计和精确的时间同步,其结构简单、性能优良.数字化TR自相关接收机可以充分利用数字信号处理算法的优势,且易于用集成电路方法实现,其实现的关键是ADC.本文从理论上分析了ADC的抽样速率、量化阶数等对数字接收机的性能的影响,提出了过高阶数的量化并不能有效改善系统性能,并在FPGA上实现了TR-UWB接收机,通过编程设计与仿真,验证了基于ADC的TR-UWB接收机实现的可行性.     

基于非下采样Contourlet和MRF的纹理图像分割

提出了一种基于非下采样Contourlet变换(NSCT)和马尔科夫随机场(MRF)相结合的纹理图像分割算法.算法包括两个步骤,首先通过NSCT实现对图像纹理特征的提取,并使用模糊C-均值完成对图像的初始分割;然后将初始分割结果用 MRF模型表示,通过贝叶斯置信传播得到图像的最终分割结果.实验结果表明,对于纹理图像,该方法在分割错误率、区域一致性以及边缘的准确性方面都比传统小波变换的方法有了明显的改善.     

Towards Japanese corpus-based semantic accessibility scale

A detailed analysis of semantic accessibility scale （SAS） based on Japanese corpus has been performed in this paper. Firstly, the method of systematic random sampling is devised for quicker comparison among six groups in きくに . Secondly, according to the direct result of comparison, different sampling ratios （SR） in groups show regular deviation. The more pages are extracted, the higher SR is involved. Thirdly, the values of SAS in groups are calculated and then contrasted with SR. The regular deviation of SR fails to bring fundamental variation of SAS even though minor difference of SAS in groups may be reflected. The irrelevance to SAS establishes the fact that SR can be used for literary critics to extract and analyze SAS in corpus-involved texts from semantic perspective.     

基于ARM和DSP的嵌入式ICE芯片扫描分析系统

集成毛细管电泳（ICE）芯片信号采集与处理系统的微型化、智能化是ICE芯片能否得到广泛应用的关键。针对传统的ICE芯片扫描分析系统结构复杂、处理速度慢、体积大等弱点,设计了一种基于DSP＋双口RAM＋ARM的嵌入式ICE芯片扫描分析系统。该系统将高速DSP与在通讯、网络和实时控制方面具有独特优势的ARM处理器,以及实时性好、接口电路简单、数据传输量大的双口RAM结合起来,为开发高性能、集成化、便携式的新型微小生化分离分析系统奠定了一定的技术基础。     

一种面向低采样率的点云数据处理网络

在直接处理点云的三维神经网络中,采样阶段实现了对原始点云中关键点的筛选,对于整个网络的性能及网络的抗噪能力具有重要作用。目前主流的最远点采样（FPS）方法在处理大规模3D点云数据时计算量大且耗时,并且低采样率时经过FPS采样后模型性能下降明显。针对这两个问题,提出一种面向低采样率的点云数据处理网络AS-Net。设计一个新的采样模块代替原backbone中的FPS,其由两个Layer组成,每个Layer基于长短期记忆网络获取原始点云与采样点云之间的联系权重,从而高效提取关键信息,去除冗余信息。在此基础上,利用注意力机制选择特征值较高的原始点云作为采样点,采样点作为后序任务的关键点输入到网络,进一步提高网络模型性能。基于ModelNet40数据集的实验结果表明,在低采样率条件下,AS-Net仍可达到81.6%的分类准确率,与使用FPS作为采样方法的网络模型相比提高52.7%。此外,其对噪声干扰具有很强的鲁棒性,对于大场景的分割时间效率优于同类采样方法。     

Data augmentation for low-resource languages NMT guided by constrained sampling

Data augmentation (DA) is a ubiquitous approach for several text generation tasks. Intuitively, in the machine translation paradigm, especially in low-resource languages scenario, many DA methods have appeared. The most commonly used methods are building pseudocorpus by randomly sampling, omitting, or replacing some words in the text. However, previous approaches hardly guarantee the quality of augmented data. In this study, we try to augment the corpus by introducing a constrained sampling method. Additionally, we also build the evaluation framework to select higher quality data after augmentation. Namely, we use the discriminator submodel to mitigate syntactic and semantic errors to some extent. Experimental results show that our augmentation method consistently outperforms all the previous state-of-the-art methods on both small and large-scale corpora in eight language pairs from four corpora by 2.38–4.18 bilingual evaluation understudy points.     

Proposal of variable sequential sampling plan having desired operating characteristics indexed by quality loss

The proportion of non-conforming items has been traditionally utilised as an evaluation criterion for quality of items. However, the proportion of non-conforming items is not necessarily useful as a proper evaluation criterion for controlling high-quality manufacturing in recent years. Accordingly, in order to achieve further quality improvement and innovation, more careful quality evaluation has been required newly. Then, a concept of quality loss in the Taguchi methods has been devised as a severe criterion of quality evaluation. Hereby, a variable single sampling plan having desired operating characteristics (OCs) indexed by quality loss has been proposed in the area of statistical quality control. By the way, the most economical sampling inspection in the average sample number (ASN) is the sequential sampling plan based on the Wald’s sequential probability ratio test. Then, from the viewpoint of cost reduction, we discuss a variable sequential sampling plan having desired OC indexed by quality loss with the aim of expansion of the utility of variable sampling plan for quality loss. As the result, the design procedure of the sequential sampling plan for satisfying some required design conditions indexed by quality loss is provided. In addition, the effectiveness of the proposed sequential sampling plan is verified through some numerical examples.