基于轨迹频率抑制的轨迹隐私保护方法

移动终端和定位技术的快速发展带来了轨迹大数据.研究者通过挖掘和分析发布的轨迹数据集,可获得一些有价值的信息.攻击者也可利用所掌握的知识对发布的轨迹数据集进行推理分析,以较高的概率推断出用户的隐私信息.轨迹抑制是一类实现隐私保护的重要方法,然而轨迹抑制的点数越多会造成数据效用越低.因此,在满足用户隐私需求的情况下,如何选择合理的抑制点来提高匿名处理后的数据效用是数据发布中要解决的重要问题.针对以上问题,文中提出两种基于轨迹频率的方案对轨迹数据进行匿名处理.第一种方案是根据情况抑制整条有问题的轨迹数据或向有问题的轨迹数据集中添加假数据;第二种方案是采用特定的轨迹局部抑制法对数据进行抑制处理.实验表明相对于已有方案,在满足同等隐私需求的情况下,文中方案处理后的数据效用提升了近30%.     

TiB2的SHS合成过程理论分析

在ＴｉＢ２陶瓷材料的自蔓延高温合成（简称ＳＨＳ）过程中，通过改变原料的起始温度，稀释剂的含量和原始颗粒的尺寸等都可以调节合成过程的绝热温度，产物中熔融相的含量，以及燃烧波蔓延的速度，人而最终影响合成产物的结构和性质。本文对上述各种关系进行了理论计算和分析，其结果对实际合成与制备过程将有着重要的指导作用。     

Preparation,characterization, and adsorption properties for metal ions of a novel chelating resin containing sulfoxide and diethylene glycol

A novel chelating resin containing sulfoxide and diethylene glycol, poly{4‐vinylbenzyl‐[2‐2‐(hydroxyethyl)ethoxyl]sulfoxide} (PVESO) was synthesized using chloromethylated polystyrene (PS‐Cl) as material. Its structure was characterized by elemental analysis, infrared spectra, and scanning electron microscopy (SEM). The adsorption capacities of the resin for Hg²⁺, Ag⁺, Cu²⁺, Zn²⁺, and Pb²⁺ at various pH values were determined. The maximum adsorption capacities for Hg²⁺ and Ag⁺ were 1.56 and 0.75 mmol g^?1 respectively. The resin had high selectivity for Hg²⁺ and Ag⁺ over the pH range 1.0–7.0. The adsorption capacities for Hg²⁺ and Ag⁺ under competitive condition were also determined by batch experiment method. In addition, the adsorption kinetics of the resin towards Hg²⁺ at different temperatures was also investigated. The results showed that the adsorption rate was governed by film diffusion at 20°C and 25°C, by particle diffusion at 30°C and 35°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 6054–6059, 2006     

Propylene epoxidation in a microreactor with electric heating

Gas phase propylene epoxidation on gold catalysts has attracted wide attention from industry and academia due to its high selectivity. However, it suffers from low propylene conversion and rapid catalyst deactivation. Experiments showed that propylene conversion could be increased by raising H₂, O₂, or C₃H₆ concentration in the feed, but the feed compositions were within the explosion limit. It was also shown that the activity of the used catalyst could be fully recovered, but the regeneration temperature was 280 °C, much higher than that for reaction. Therefore a microchannel reactor was devised to suppress explosion and was constructed with Fecralloy, to raise the temperature rapidly for catalyst regeneration by electric heating. In two minutes the temperature of the reactor could be raised from 50 to 300 °C. Catalysts were coated on the alloy belt by dip coating, and the performance of the reactor was evaluated under different operating conditions. Results showed that in the microreactor the overall reaction rate was controlled mainly by the intrinsic reaction rate, and also influenced by film diffusion to a certain extent. The deactivated catalyst was regenerated in the microchannel reactor and the activity was fully recovered.     

碟式分离机转鼓零件的最宜超转速探讨

本文通过对超速处理后的AISI316L钢的碟式分离机转鼓零件在各种工况下的应力场分析,探讨了分离机转鼓超速自增强的最宜超转速问题,并提出了确定最宜超转速的基本原则和方法.通过分析表明:用本文方法所得到的最宜超转速与已知的国外数据是相当一致的.     

伴有平衡反应的分离过程的数学模拟——(Ⅱ)催化精馏塔的模拟计算

提出了平衡反应的非均相催化反应精馏过程的微分数学模型。应用多目标打靶法和 Newtor-Raphson 迭代对模型方程进行了求解。本算法应用于非理想系统,反应动力学未知的快速可逆反应过程。可求得沿塔最大转化率和平衡浓度分布。应用本算法对 MTBE 的催化反应过程进行了模拟计算,能快速稳定收敛。计算结果与文献数据进行比较,表现出良好的一致性。     

进口刀盘圆环失效原因及改进

首先从材料力学角度分析了抚顺石化公司干法腈纶装置原进口切断刀盘圆环失效的原因 ,认为此种切断刀盘圆环系二维增强结构层压板 ,层间没有纤维增强 ,需要解决由二维增强向三维增强的过渡。给出了改进办法 ,寻求到三维增强的替代材料。同时介绍了机械加工测试及在线实验     

Graph regularized multiset canonical correlations with applications to joint feature extraction

Multiset canonical correlation analysis (MCCA) is a powerful technique for analyzing linear correlations among multiple representation data. However, it usually fails to discover the intrinsic geometrical and discriminating structure of multiple data spaces in real-world applications. In this paper, we thus propose a novel algorithm, called graph regularized multiset canonical correlations (GrMCCs), which explicitly considers both discriminative and intrinsic geometrical structure in multiple representation data. GrMCC not only maximizes between-set cumulative correlations, but also minimizes local intraclass scatter and simultaneously maximizes local interclass separability by using the nearest neighbor graphs on within-set data. Thus, it can leverage the power of both MCCA and discriminative graph Laplacian regularization. Extensive experimental results on the AR, CMU PIE, Yale-B, AT&T, and ETH-80 datasets show that GrMCC has more discriminating power and can provide encouraging recognition results in contrast with the state-of-the-art algorithms.     

高效塔填料——共轭环的性能研究

本文总结了我国自行开发的高效散堆填料——共轭环的流体力学与传质性能,论述了共轭环的结构特点.用φ38塑料共轭环、鲍尔环、阶梯环做对比实验,其结果为:共轭环的每米压强降比阶梯环低40-45%、比鲍尔环低50—55%,共轭环的传质单元高度比阶梯环低15%、比鲍尔环低30%,即共轭环的流体力学和传质性能均比阶梯环、鲍尔环优良.