面向一类混合退化装备RUL预测的平行仿真技术

针对一类带离散冲击的混合退化装备剩余寿命预测问题,研究了面向混合退化装备剩余寿命预测的平行仿真技术.提出以混合Wiener状态空间模型为基础仿真模型,以泊松冲击到达为模型选择判据,在实时退化数据驱动下,实现仿真模型在线选择,利用强跟踪滤波和期望最大化算法进行仿真模型数据同化和未知参数在线估计,从而实现仿真模型演化,提高仿真模型逼真度.在此基础上,实现了基于平行仿真的剩余寿命实时预测.利用某轴承性能退化数据对平行仿真方法进行了实例验证,仿真结果表明平行仿真方法能有效仿真轴承的性能退化过程,剩余寿命预测的不确定性小、精度高.      

采用GRU-MC混合算法的锂离子电池RUL预测

锂离子电池的剩余使用寿命预测是电池管理系统的重要组成部分.为解决锂离子电池剩余使用寿命预测不准确的问题,提出一种基于门控循环单元和马尔科夫链的锂离子电池剩余使用寿命预测方法.首先,对数据进行数据清洗和数据规范,选择构建特征矩阵;然后,搭建基于门控循环单元网络的预测模型,并运用马尔科夫链算法对预测模型的初步结果进行误差修...     

考虑不确定测量的惯性平台剩余寿命自适应预测

针对现有剩余寿命预测方法未考虑测量误差引起的不确定性,且存在预测不确定性大的问题,提出了一种基于Wiener过程的退化过程建模方法,并将测量的不确定性考虑到剩余寿命预测中,推导出了剩余寿命的概率分布。为了实时更新模型参数,利用Kalman滤波算法实时估计Wiener过程中的漂移系数,并利用期望最大化算法实时估计其它相关参数。以某型号惯性平台的退化测量数据为例,进行了实验验证,结果表明,相比其它算法,文中算法能够降低剩余寿命预测的不确定性,提高预测精度。     

基于退化曲线相似性的剩余使用寿命估计方法

为解决预测与健康管理领域关键设备的剩余使用寿命(RUL)估计问题,提出一种基于退化曲线相似性匹配的方法估计设备剩余使用寿命。离线训练环节,使用线性回归的方法将多维传感器数据融合为一维健康度(HI),并拟合HI轨迹,采用步进方式提取大量固定长度HI曲线后,通过K-Means++聚类缩减曲线数量,这些曲线与设备退化模式相关,隐含剩余使用寿命(RUL)信息。在线估计环节,将曲线与测试样本进行比较,匹配到的曲线用于估计剩余使用寿命。通过对航空涡扇发动机失效数据测试,验证了方法的有效性。     

基于多阶段退化建模的谐波减速器实时可靠性评估与寿命预测

谐波减速器是工业机器人的关键核心部件,其可靠性的实时评估和剩余寿命预测对于提升工业机器人的工作性能和健康监管具有重要意义.作为一种复杂的高精度机械部件,其退化过程表现出明显的多阶段性特点.因此,针对谐波减速器的退化特性,提出基于Gamma过程的多阶段退化模型对谐波减速器性能退化过程进行精确描述.首先,根据谐波减速器退化趋势的变化,进行多阶段退化过程的划分;然后采用历史性能指标数据,基于最大皮尔逊相关系数准则估计模型先验分布的超参数,建立基于Gamma过程的多阶段退化模型.在此基础上,针对在役设备的实际运行特点和工程现场中性能指标数据获取困难的问题,提出采用振动特征来建立高斯过程回归模型,对性能指标值进行精准预测以实现对退化模型后验分布参数的实时更新.最后在此基础上对谐波减速器进行实时可靠性评估和剩余寿命预测.通过对谐波减速器可靠性实验数据的分析表明,所提出的方法能够实现可靠性的实时评估,并且与单一阶段退化模型相比,该方法对剩余寿命的预测精度更高.     

基于状态空间的惯性测量组合剩余寿命在线预测

实时准确的剩余寿命预测能够为惯性测量组合的维护策略安排提供有效的决策支持。由于反映惯性测量组合退化状态的性能指标不能直接监测或直接测量带有噪声,因此需要构建状态空间模型预测惯性测量组合的剩余寿命。考虑到惯性测量组合的性能退化指标随时间呈现非线性特征,首先采用基于非线性漂移的Brown运动(Brownian motion,BM)建模其退化状态,然后基于构建的状态空间模型,利用期望最大化(expectation-maximization,EM)算法和Kalman滤波(Kalman filter)实时估计和更新退化状态和模型未知参数。并且将状态估计的分布函数引入剩余寿命的预测过程,近似得到了剩余寿命分布的解析形式,实现了剩余寿命的实时预测与更新。最后,对惯性测量组合的剩余寿命实时预测问题进行了实验分析,结果表明该方法具有较高的预测精度与较小的预测不确定性。     

基于深度学习与粒子滤波的刀具寿命预测

刀具在加工过程中会受到材料的挤压、摩擦、冲击与腐蚀等因素影响,导致切削刃出现崩刃、磨损等现象.这些现象使得工件尺寸出现偏差,严重时甚至会对机床和人员带来伤害.有效的刀具剩余使用寿命预测可以提高加工效率,保证加工精度,降低加工成本,因此具有重要的研究价值.针对反映刀具磨损程度的趋势性特征自学习提取与刀具剩余使用寿命预测问题,提出了基于深度学习与混合趋势粒子滤波的刀具剩余使用寿命预测方法.使用刀具未发生磨损的信号特征训练降噪自编码器,然后将刀具各磨损阶段下的信号特征输入训练好的降噪自编码器中,提取其重构误差作为单调性特征,为了解决样本数量不足带来的过拟合的问题,对原始样本进行了加噪处理.考虑到传统粒子滤波算法进行刀具剩余使用寿命预测的过程中无法自适应调整状态方程,提出混合趋势粒子滤波算法来实现刀具剩余使用寿命预测.采集刀具全寿命周期的切削力信号并进行处理与分析,分析结果证明了所提方法能够有效实现反映刀具磨损的趋势性特征自提取,该特征提取方法可以减少人为因素的影响,降低训练成本,同时,相比于传统粒子滤波,混合趋势粒子滤波算法对刀具剩余使用寿命预测精度更加准确可靠.     

基于局部敏感哈希 双层随机森林的燃气轮机剩余使用寿命预测

针对燃气轮机剩余使用寿命预测中监测数据信息利用不够充分、退化过程难以表示、预测精度低等问题,提出了一种基于局部敏感哈希-双层随机森林的燃气轮机剩余使用寿命预测方法.该方法首先使用主成分分析充分利用多维监测数据信息构建健康因子来表示退化过程,并通过滑动截取的方法在健康因子曲线上获取训练数据;然后,通过p-stable分布局部敏感哈希相似性搜索算法匹配和需要预测的样本最相似的样本;进而,使用双层随机森林对剩余使用寿命进行回归预测.利用C-MAPSS数据集验证了该方法的有效性和准确性,研究结果可为其他非线性退化系统剩余使用寿命预测提供一定的参考.     

基于新健康因子的锂电池健康状态估计和剩余寿命预测

容量和内阻是评估锂离子电池健康状态和预测其剩余寿命的重要指标,然而电池容量和内阻难以直接在线测量.通过分析锂离子电池充电过程中电流和电压的变化特征后提取出两种健康因子,并且证明所提因子与电池容量高度相关,进一步建立了用于锂电池容量估计的两因子线性回归模型.在此基础上,通过结合BP(back propagation)神经网络和粒子群优化思想设计锂离子电池健康状态估计算法.考虑到锂电池的健康状态和剩余使用寿命之间存在一定的映射关系,因此再利用所提取的健康因子和其健康状态估计结果设计了锂电池的剩余使用寿命预测算法.实验结果表明,所提取的健康因子能够准确地进行电池容量估计并应用于在线评估锂离子电池的健康状态和预测其剩余使用寿命.     

一种混合退化系统剩余寿命预测方法

针对传统的预测方法不能同时考虑线性和非线性退化问题,提出了一种基于维纳过程的带随机参数和确定参数的混合退化模型.基于首达时间(FHT)的概念给出了剩余寿命(RUL)的解析渐进显式形式,模型中随机参数通过Kalman滤波技术实时更新,确定参数采用极大似然估计进行估计.最后,采用陀螺仪实验数据验证了该方法的有效性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.