基于分簇和启发式的隐私保护算法研究

针对社交网络存在安全隐患和隐私风险,提出了基于分簇算法的启发式修改。基于最短路径,提出了一个最大贪心保护算法,追求数据隐私和数据功用的平衡。从数学分析和实验结果看,实现了一定的隐私保护和功用要求。     

基于深度循环神经网络的社交网络用户情感研究

目的 将深度学习与社交网络、情感计算相结合,探索利用深度神经网络进行社交网络用户情感研究的新方法和新技术,探索模型在用户需求分析和推荐上的应用.方法 自动筛选和挖掘海量社交网络数据,研究具有长时记忆的非先验情感预测方法,对网络中海量的用户数据、人与人之间关系进行建模,为关联时间序列创建LSTM模型,并结合其相互关系融入统一的大型深度循环网络中.具体包括:基于注意力模型的社交网络异构数据处理;基于深度LSTM的长时记忆建模,研究子网络选取、深度LSTM设计,以及针对社交网络的大型网络结构设计;基于社交网络情感模型和强化学习的推荐算法.结果 提高了分析的准确度,降低了对先验假设的依赖,减轻了人工情感模型的工作量和偏差,增强了对不同网络数据的普适性;供深度模型使用.结论 研究成果促进了深度学习与情感计算的结合,可推动网络用户行为分析和预测的研究,可用于个性化推荐、定向广告等领域,具有广泛的学术意义和应用前景.     

基于联邦元学习的安全移动边缘计算卸载框架

移动边缘计算(MEC)技术通过卸载部分计算任务到边缘服务器,可将第5代网络(5G)、云计算、大数据和人工智能等技术延伸到物联网终端。针对如何高效卸载计算任务和保障边缘数据隐私安全2个关键问题,在综述计算卸载性能优化研究基础上,本文提出了一种融合联邦学习和元学习的计算卸载应用框架,通过对计算任务的计算卸载以及计算资源的联合优化,从而实现系统加权时延和最小。在不泄露用户数据隐私的前提下,联合多个边缘服务器共同训练一个全局模型,并实现边缘服务器个性化计算卸载应用。在新的计算任务场景下,全局模型的网络参数仅用少量训练样本就能快速收敛。实验测试结果表明,本文提出的基于联邦元学习的计算卸载框架可适应未来边缘计算应用的隐私安全需求。     

FVSk-匿名:一种基于k-匿名的隐私保护方法

为了确保数据发布应用环节中个人敏感隐私数据信息的安全,深入研究了k-匿名技术的机制及性能,针对其不能完全有效地防止敏感属性数据信息泄漏的问题,通过引入真子树的概念和全新的敏感属性值选择手段,在实验探索的基础上,提出了一种基于k-匿名隐私保护模型的新的数据发布隐私保护方法——FVS k-匿名隐私保护方法。这种隐私保护方法继承了k-匿名技术实现简单、处理数据便捷的优点,而且弥补了其保护个人敏感隐私数据信息不完全、不充分的缺点。优化后的FVS k-匿名方法能有效地防止个人敏感隐私数据信息的泄漏,确保个人敏感隐私数据信息的安全。     

基于大数据分析的隐私信息保护策略研究

网络在人们的生活中越来越重要,保障个人信息的安全成了重点议题。因此,该文进行了基于大数据分析的隐私信息保护策略研究。构建隐私信息保护模型,创建基于大数据分析的Agent保护信息算法,控制隐私数据的存储与访问情况。基于大数据分析的隐私信息保护策略研究的对比试验表明：信息保护策略能有效减少隐私信息被破解,使用该方法时隐私保护性能显著提高。     

DHT系统的安全性优化方法研究

对分布式哈希表(DHT)系统的安全脆弱性问题进行了研究,提出了多种安全性优化策略,并给出了一个原型系统。进行了真实网络实验,实验数据表明,现有DHT网络易受索引毒害和路由污染攻击,产生的错误查询结果甚至会引发更大规模的网络安全事件。通过改进一个个DHT系统的节点ID生成机制、路由表更新机制和搜索路径选择机制,从系统运行的各个阶段提升其安全场,抵御攻击者共谋。基于上述方法设计的原型系统在保证平均查询跳数增加不到1跳的情况下,在共谋攻击节点占比60%的网络中,将系统查询成功率保持在65%以上,其方法适用于各种分布式哈希表结构,具有重要的实际应用前景。     

基于社交的空间文本skyline查询

将社交信息应用到空间文本skyline查询中,提出了基于社交的空间文本skyline(SSTS)查询。SSTS查询中skyline对象的选择依赖于三个方面:与查询用户之间的距离、与查询关键字的文本相关性和在用户中的流行性。该查询引入了新型的函数计算它的社交相关性。为了提高查询者的满意度,扩展了SSTS查询,提出了受限的基于社交的空间文本skyline(constrained SSTS,CSSTS)查询,同时引入了一个新颖的概念受限skyline。针对每一种查询,应用了裁剪策略和终止条件,提高了查询速度。最后,通过实验验证了所提方法的有效性。     

分布式本体库存储模型的设计与优化

针对如何高效地构建用于语义交互的分布式本体库展开了研究。首先,分析了基于本体的语义交互平台的通用体系结构,进而明确分布式本体库在平台中的作用,提出了一种分布式本体库存储模型。围绕该模型,详细讨论了网络本体库与本地本体库的映射方法,语义数据的编码方法,然后详细分析了该模型中指令分发和数据演化组件的工作机制,最后通过实验验证了:在集群存储模式下,对于大数据量查询,网络数据传输对查询时间开销的影响远远小于查询本身,从而为分布式本体库存储效率的优化奠定了基础,即在本体库中采用分布式集群存储可以达到优化检索效率的目的。该存储模型已经在STASIS平台中得到应用。     

基于改进差分克里金的分布式光纤异常数据修复模型

分布式光纤监测过程中异常值的识别和丢失信号的修复是数据处理的重要环节.本文提出一种基于改进差分克里金的分布式光纤异常数据修复模型(KWSDE)用于解决分布式光纤异常传感数据问题.首先建立了光纤传感数据特征的求解模块,接着针对噪声信号提出了基于滑动窗口的加权平均差分降噪模块,然后构建基于自适应控制参数和加权最小二乘法的改进差分克里金修复模块,并给出了算法的具体实施步骤.最后为了验证所提模型的可行性,本文设计了分布式光纤的冲击实验分析其适用性.结果表明,在满足分布式光纤监测系统的数据特征前提下,本文所提出的修复模型的平均预测精度R2达到了0.9486,证明了其工程应用价值.     

轨道交通噪声计算方法研究

通过建立轨道交通噪声理论计算模型，研究了轮轨相互作用关系及由轮轨表面不平顺而引起的滚动噪声，给出了车轮、钢轨辐射噪声声压级谱关系式，利用有关文献中给定的实验数据，计算了因轮轨表面粗糙度而引起的城市轨道交通噪声，计算结果表明大约在1700Hz以下频段，主要以钢轨振动噪声为主，而在1700Hz以上频段，车轮振动噪声占主导地位。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...