Uncooperative gait recognition by learning to rank

Gait is a useful biometric because it can operate from a distance and without subject cooperation. However, it is affected by changes in covariate conditions (carrying, clothing, view angle, etc.). Existing methods suffer from lack of training samples, can only cope with changes in a subset of conditions with limited success, and implicitly assume subject cooperation. We propose a novel approach which casts gait recognition as a bipartite ranking problem and leverages training samples from different people and even from different datasets. By exploiting learning to rank, the problem of model over-fitting caused by under-sampled training data is effectively addressed. This makes our approach suitable under a genuine uncooperative setting and robust against changes in any covariate conditions. Extensive experiments demonstrate that our approach drastically outperforms existing methods, achieving up to 14-fold increase in recognition rate under the most difficult uncooperative settings.     

纳米SiO2粉体的制备与研究

纳米SiO2粉体的制备是以硅酸钠和盐酸为原料，添加适宜的稳定剂(非离子表面活性剂)和分散剂，在适宜的pH值和温度下，采用化学沉淀法合成。研究表明，要得到性能优良纳米的SiO2粉体，最佳工艺条件为：温度20～40℃，pH=6，反应液质量浓度P1=20g／L，P2=1．20g／L，反应时间15min。结果表明：制备的纳米SiO2粒径30～50nm，比表面积大，分散性好，质量优良，可达到产业化的生产。     

教学研究型大学信息安全专业人才培养方案优化和实践

分析了信息安全专业的特点;讨论了教学研究型大学信息安全专业人才培养中存在的人才特点不够鲜明、动手能力不足、知识不够全面、自主学习时间得不到保证等问题;针对信息安全专业的特点和教学研究型大学的自身情况,提出了增强学生实践能力、优化课程设置、提高教师素质等优化措施。这些优化措施在本校得以实践,对于解决教学研究型大学存在的问题具有较好的效果。     

一种基于浏览代价优化的电视网页重构方法

随着智能家庭概念的发展与推广,出现了大量面向电视机用户的Web应用。由于用户与电视机之间通过遥控的方式进行交互,一方面使得网页浏览代价受页面元素排布的影响较大,而另一方面,电视机网页元素类型和数量少的特点,使得对其进行自动优化成为可能。考虑到包括按键式遥控器、手势、触屏等电视机交互方式,根据不同的交互方式的特点提出了页面浏览代价的计算方法;考虑到元素类型、位置、大小、内容关键字、网页结构等信息,提出了一种页面元素可替换性评估方法;在这两种方法的基础上,基于网页浏览代价全局最小化的原则,提出了根据页面的访问情况动态对网页进行自动重构的方法。在一个包含116个页面的电视机Web应用中采用该方法进行的实验验证了方法的正确性和有效性。     

酸性铵盐沉钒条件实验研究

以温度、时间、搅拌强度为变量，以沉淀率、抽滤后滤饼含水量、烘干后多钒酸铵(APV)中杂质含量等作为评价指标，对酸性铵盐沉钒条件进行了研究. 结果表明：以含钒30 g/L左右的溶液为原料，加硫酸铵后用硫酸调节pH至2.2左右，沸水浴(95℃)中沉淀120 min左右，桨式搅拌转速300 r/min，可获得99%以上的沉淀率，抽滤滤饼含水量20%以下，烘干后APV含Na 0.70%~ 1.08%, S 0.78%~1.20%.     

Effect of operating conditions in removal of arsenic from water by nanofiltration membrane

The removal of arsenic from synthetic waters and surface water by nanofiltration (NF) membrane was investigated. In synthetic solutions, arsenic rejection experiments included variation of arsenic retentate concentration, transmembrane pressure, crossflow velocity and temperature. Arsenic rejection increased with arsenic retentate concentration. Arsenic was removed 93-99% from synthetic feed waters containing between 100 and 382 μg/L as V, resulting in permeate arsenic concentrations of about 5 μg/L. Under studied conditions, arsenic rejection was independent of transmembrane pressure, crossflow velocity and temperature. In surface water, the mean rejection of As V was 95% while the rejection of sulfate was 97%. The co-occurrence of dissolved inorganics does not significantly influence arsenic rejection. The mean concentration of As in collected permeated was 8 μg/L. The mean rejection of TDS, total hardness and conductivity were 75, 88 and 75% respectively.     

Transition phenomena of polymers in mixed solvents in the vicinity of theta conditions: Effect of preferential adsorption

Viscosimetric measurements were obtained with the ternary systems polystyrene/dioxane/methanol, polystyrene/benzene/methanol and poly(methyl methacrylate)/dioxane/cyclohexane, changing the solvent mixture composition at constant temperature. The polystyrene and poly(methyl methacrylate) systems exhibit a transition phenomenon with solvent-mixture composition in which the polymer is just above the theta condition. In the case where two theta conditions occur ((θ-intra, θ-inter) the transition point is closely related to the intramolecular theta conditions. Moreover the intramolecular theta conditions vary with the molecular weight in the region of molecular weights where the preferential adsorption also varies. This variation induces a variation of the transition point with molecular weight which obeys a formula analogous to that giving the variation of the preferential adsorption with molecular weight.     

Studies on fluorinated polyurethanes by X-ray diffraction and density functional theory calculations with periodic boundary conditions

Thin-film wide-angle X-ray diffraction, small-angle X-ray scattering, and density functional theory calculations using B3LYP hybrid functional with the two-dimensional periodic boundary conditions (2D-PBC) have been applied to study the crystal structures of parent and fluorinated polyurethanes. The crystal structures from 2D-PBC-B3LYP calculation and experiments showed the hard-segment chains within crystallites adopted an extended-chain conformation for polyurethanes. Energetically, the parent polyurethane preferred an alternating hydrogen-bonded sheet structure while the fluorinated one adopted a progressive hydrogen-bonded sheet structure.     

硅灰石合成高比表面积二氧化硅的工艺研究

一系列硅灰石酸处理实验表明,产物物理性质与反应速度、反应时间、中和最终ｐＨ值等工艺条件有关。同时发现,如果工艺条件恰当,可以制得４００～６００ｍ＾２／ｇ的高比表面积二氧化硅。     

酚试剂法测定室内空气中甲醛的实验条件优化

为了提高酚试剂法测定室内空气中甲醛的准确性,优化实验条件,系统研究了盐酸介质浓度、显色剂加入量、显色时间、显色反应温度和稀释液类型等因素对吸光度的影响,研究结果表明,采用0.1 mol/L盐酸配制的硫酸铁铵显色剂,显色剂加入量对吸光度影响不显著,最佳加入量为0.4 mL;显色反应温度对吸光度影响明显,最佳温度应控制在25～35℃范围内;稳定的显色反应时间应控制在18～30 min内,以20 min为宜;当甲醛质量浓度较高时,可选用去离子水或酚试剂吸收液进行适当的稀释。在较优的实验条件下,测定的甲醛质量浓度与吸光度在0～2.0μg/mL范围内呈良好的线性关系,r=0.999 9。