摘要：The simplified analysis method based on the static equilibrium is generally adopted for raft design. The secondary stress of superstructure due to the differential settlement of the foundation is neglected, which leads to larger support moments and longitudinal bending of raft compared with real values. The spring constitutive relation of composite foundation is obtained by the flat plate loading tests in Karst region. The interaction between the spring and the raft is equivalent to the interaction between the composite foundation and the raft. The model for superstructure-raft-composite foundation interaction analysis is thus established and the raft is designed. This method not only considers the nonlinear properties of composite foundation but also analyzes the influence of superstructure on bending moment and deformation of raft. Compared with the inverted floor method, the calculated values of moment become more reasonable and uneven settlements are considered. This can be references to the design of raft foundation in similar regions.

摘要：Studying the piled raft behavior has been the subject of many types of research in the field of geotechnical *** studies have been conducted to understand the behavior of these types of foundations,which are often used for uniform loading on the raft and piles with the same length,while generally the transition load from the upper structure to the foundation is non-uniform and the choice of uniform length for piles in the above model will not be optimally economic and *** most common method in identifying the behavior of piled rafts is the use of theoretical relationships and software *** precise identification of this type of foundation behavior can be very difficult due to several influential parameters and interaction of set behavior,and it will be done by doing time-consuming computer analyses or costly full-scale physical *** the meantime,the technique of artificial neural networks can be used to achieve this goal with minimum time consumption,in which data from physical and numerical modeling can be used for network *** of the advantages of this method is the speed and simplicity of using *** this paper,a model is presented based on multi-layer perceptron artificial neural *** this model pile diameter,pile length,and pile spacing is considered as an input parameter that can be used to estimate maximum settlement,maximum differential settlement,and maximum raft *** this model,we can create an extensive domain of results for optimum system selection in the desired piled raft *** of neural network indicate its proper ability in identifying the piled raft *** presented procedure provides an interesting solution and economically enhancing the design of the piled raft foundation *** innovative design method reduces the time spent on software analyses.

摘要：raft是最为流行的分布式共识协议之一.自2014年被提出以来,raft协议及其变体在各种分布式系统中被广泛应用.为了证明raft协议的正确性,开发者使用TLA+形式化规约对协议设计进行了建模和验证.但由于抽象的形式化规约与实际的系统实现源码间存在鸿沟,基于raft实现的分布式系统中仍然会违背协议设计并引入复杂的缺陷.设计基于TLA+形式化规约的测试方法来检测raft协议实现中的缺陷.具体而言,将形式化规约匹配到相应的系统实现,并用形式化规约所定义的状态空间来指导系统实现的测试过程.为评估所提方法的可行性和有效性,针对两个不同的raft实现进行系统化测试,并发现3个未知缺陷.

摘要：Choosing the equipment with good shock-resistant p erformance and taking shock protection measures while designing the onboard sett ings, the safety of onboard settings can be assured when warships, especially su bmarine subjected to non-contact underwater explosion, that is, these means can be used to limit the rattlespace (i.e., the maximum displacement of the equipme nt relative to the base) and the peak acceleration experienced by the equipment. Using shock-resistant equipments is one of shock protection means. The shock- resistant performance of the shock-resistant equipments should be verified in t he design phase of the equipments. The FEA (finite element analysis) software, for example, *** ○R , can be used to verify the shock-resistant performance. *** ○R and *** are used for modeling and analyzing the floating raft vibration isolating equipment. The model of the floating raft and the floating raft vibration isolating system are theoretically analyzed and calculated, and the analysis results are in agreement with the test results. The transient response analysis of the system model follows the modal analysis of the floating raft vibration isolating system. And it is used to verify the shock-resistant performance. The ana lysis and calculation method used in this paper can be used to analyze the shock -resistant performance of onboard shock-resistant equipments.

摘要：The finite element method was used for analysis of raft foundation design in high-rise *** with other conventional methods,this method is more adapted to the practical condition since both superstructure stiffness and soil conditions were considered in *** calculation results by example show that the base reaction is more uniform and the maximum reaction decreases ***,the raft foundation design is more economic without any loss of security for high-rise building.

摘要：传统的raft算法容易因受到恶意攻击而导致效率低下。针对raft算法在执行过程中可能被攻击者探测到Leader身份进而发动攻击的问题,利用可验证随机函数的随机性和非交互式特性,改进了原有raft算法,隐藏了选主过程中Leader的身份的同时避免了原算法的多轮选举问题。提出的改进raft算法的详细设计了可验证随机函数的实现并将其融入到选主过程中,并且分析了改进方案的系统安全性和稳定性,对比了不同共识算法在各需求场景下的表现。仿真试验表明:改进后的算法在选主过程中隐藏了被选中节点的身份,在保证系统稳定性的前提下提高了系统安全性,并且在系统节点越来越多时提高选主的时间效率的表现更好。

摘要：基于可逆加成-断裂自由基聚合(raft),设计并合成了一种新型的梳状嵌段共聚物。通过凝胶渗透色谱仪(GPC)、核磁共振氢谱仪(^(1)R)、傅立叶变换红外光谱仪(FT-IR)等对共聚物进行了测试表征。将共聚物用于酞菁蓝颜料分散,利用马尔文激光粒径仪和旋转黏度计对其分散性能进行了测试,并与市售的某进口分散剂进行了对比。结果表明:所制备的梳状嵌段共聚物分散剂能使酞菁蓝颜料分散良好,色浆具有粒径小、黏度低、耐沉降、稳定性高的优异性能。

摘要：为了解决raft算法中日志提交的严格串行化设计,提出一种raft协议变体:并行提交raft (PC-raft). PCraft在日志提交阶段运用流水线,重新设计日志缓冲区,实现日志的乱序提交.传输方式使用RDMA网络,在提高日志传输的并发性的同时加快传输速度.在日志执行阶段,采用批处理,将多条指令打包发送给状态机逐条执行.针对日志并行提交情况下会出现的幽灵复现问题,采用LSN与任期号结合的方式保证日志的安全性.针对日志乱序提交会出现的日志空洞问题,重新设计领导者选举算法,在选举中加入临时领导者,保证选举出的领导者能最快恢复日志.测试结果证明PC-raft对比raft在吞吐量方面有着明显的性能提升,同时延迟更低,并且在日志指令依赖频繁的情况下,吞吐量比现有基于raft的变体更高,延迟也更低.

摘要：可逆加成断裂链转移自由基聚合(raft)作为可控/“活性”自由基聚合其中的一种方法,跟传统自由基聚合一样,适用的单体范围广,聚合条件温和,易工业化且成本低,同时又具备结构精确可控,相对分子质量分布窄且可以提前设计预测控制的优点,能够进行分子结构设计合成嵌段和接枝或星形等不同结构的聚合物。介绍了raft聚合的基本机理、单体种类、raft剂的选择、raft聚合诱导自组装(PISA)方法和应用,探讨了现在raft聚合面对的挑战和未来发展趋势。

摘要：raft一致性算法由于其原理清晰、易于实现等优点,已得到了行业的广泛应用。然而,作为一种简化版的类Paxos方案,raft算法牺牲了部分性能。在不同的具体应用场景中,可根据实际应用,对其做出相应改进。对于由稳定性不佳的设备构成的分布式系统,在工作周期内将经历多次选举管理节点过程。在每次选举过程中,继续使用raft算法进行选举操作将存在小概率经历多次超时选举。为了减少极端情况下选举过程的耗时,本文基于历史日志计算值设计一种改进版一致性算法LC-raft。通过对固定时段的历史日志故障次数统计,构建一套节点稳定性评价指标,并修改选举流程,实现在系统网络通畅情况下最多经历一次计时器时间完成管理节点选举。同时,基于Docker容器引擎,设计一系列模拟实验实现各种节点规模的选举过程,通过多次实验的统计值验证本算法在选举过程中的良好性能。