Human Action Recognition Based on Supervised Class-Specific Dictionary Learning with Deep Convolutional Neural Network Features

Human action recognition under complex environment is a challenging work. Recently, sparse representation has achieved excellent results of dealing with human action recognition problem under different conditions. The main idea of sparse representation classification is to construct a general classification scheme where the training samples of each class can be considered as the dictionary to express the query class, and the minimal reconstruction error indicates its corresponding class. However, how to learn a discriminative dictionary is still a difficult work. In this work, we make two contributions. First, we build a new and robust human action recognition framework by combining one modified sparse classification model and deep convolutional neural network (CNN) features. Secondly, we construct a novel classification model which consists of the representation-constrained term and the coefficients incoherence term. Experimental results on benchmark datasets show that our modified model can obtain competitive results in comparison to other state-of-the-art models.     

浪形保持架表面毛刺的解决方法

论述了轴承浪形保持架产生毛刺的原因及相应的解决方法,对保证轴承质量有重要作用。     

涤纶表面TiO2薄膜的制备及抗紫外线性能研究

通过磁控溅射将二氧化钛（TiO₂）沉积在涤纶织物表面形成薄膜,制备二氧化钛/涤纶（TiO₂/PET）抗紫外线功能织物,探讨制备过程中磁控溅射时间和溅射功率对织物抗紫外线功能的影响,分析TiO₂薄膜的紫外线吸收和屏蔽机理,同时检测织物隔热、热稳定性能的变化情况. 结果表明:在PET织物表面沉积TiO₂薄膜可改善织物的抗紫外线性能,归因于TiO₂薄膜对紫外光较好的吸收和对紫外可见光有效的屏蔽能力;且因TiO₂薄膜在溅射150 W以上的功率下粗糙度增加、厚度减少,当溅射功率为150 W,溅射时间为90 min时,TiO₂/PET织物具有较强的抗紫外线能力,其紫外线防护系数（Ultraviolet Protection Factor,UPF）达到1211.19;同时,TiO₂薄膜的沉积赋予了PET织物良好的热稳定性能和隔热性能.     

在-55~125℃范围内误差小于±0.3℃硅基温度传感器

提出了基于寄生参数自校正的高精度温度传感器,并给出了基于CSMC 0.5μm混合信号CMOS工艺的仿真结果.利用CMOS工艺衬底pnp三极管的发射区-基区pn结作为温度传感单元,提出了易于开关-电容电路实现的寄生电阻校正方法,消除了基区电阻非线性对温度测量的影响,提高了测量精度.电路仿真结果显示,系统测温误差在-55℃～125℃范围内仅为±0.3℃.     

基于认知无线电的广东省UHF频段监测与分析

在珠三角地区对超高频(Ultra High Frequency,UHF)频段开展了近两个月的监测,给认知无线电技术在广东省的应用提供了现实依据.结果表明:频段利用率普遍较低,同一频段在不同地区、不同时段的利用情况存在一定的差异.对广播电视频道占用情况的建模体现了频道开放时间的规律性;根据各频率点的利用率情况将频率划分为五个占用程度,可得出可供认知无线电用户接入的连续空闲带宽的概率分布.     

Sigma-Delta 调制器的建模、分析和设计

This paper introduces a new method for SC sigma–delta modulator modeling. It studies the integrator's different equivalent circuits in the integrating and sampling phases. This model uses the OP-AMP input pair's tail current (I₀) and overdrive voltage (v_on) as variables. The modulator's static and dynamic errors are analyzed. A group of optimized I₀ and v_on for maximum SNR and power × area ratio can be obtained through this model. As examples, a MASH21 modulator for digital audio and a second order modulator for RFID baseband are implemented and tested, and they can achieve 91 dB and 72 dB respectively, which verifies the modeling and design criteria.     

航天器贮箱液体的有效转动惯量(下)

分析整理了航天器圆环筒形平底贮箱内液体的有效转动惯量计算方法,修正了现有文献中的错误,在常用的参数范围内对液体的有效转动惯量进行了计算,对其变化规律和影响因素做了物理分析,推导了液体滚转有效转动惯量的计算公式,并给出了适用的近似计算方法.对于纵向挡板引起的液体滚转有效转动惯量,给出了工程计算方法,能够确定滚转时液体的有...