A Diagnosis Method of Vibration Fault of a Steam Turbine Based on Information Entropy and Grey Correlation Analysis

The vibration fault, one of the common faults in the steam turbine generator unit, brings great damage to the production and the running process. It is well known that the information entropy is to describe the degree of indeterminacy of the system, so the information entropy can be used to measure Despite its efficiency, one kind of information entropy is just enabled to identify make up for this limitation, based on nalysis was studied for vibration fault the vibration condition of the unit. certain part of the faults. In order to the faulty signals collected from the rotor test platform, the grey correlation adiagnosis of steam turbine shafting in this paper. The reference faulty matrix and the calculation model of grey correlation degree was established based on three kinds of information entropy. The analysis shows that grey correlation analysis is a useful method for fault diagnosis of shafting and can be used as a quantitative index for fault diagnosis.

An Availability Evaluation Method of Web Services Using Improved Grey Correlation Analysis with Entropy Difference and Weight

Web services is one of the basic network services, whose availability evaluation is of great significance to the promotion of users’ experience. This paper focuses on the problem of availability evaluation of Web services and proposes a method for availability evaluation of Web services using improved grey correlation analysis with entropy difference and weight (EWGCA).This method is based on grey correlation analysis, and use entropy difference to illustrate the changes of availability, set weight to quantize availability requirements of different operations or transactions in services. Through simulation experiment in high load scenarios for Web services, the experiment result shows that our method can realize hierarchical description and overall evaluation for availability of Web services accurately in the case of smaller test sample volumes or uncertain data even in the field of big data.

Quantitative and comparative analysis of hyperspectral data fusion performance

Hyperspectral data fusion technique is the key to hyperspectral data processing in recent years. Many fusion methods have been proposed, but little research has been done to evaluate the performances of different data fusion methods. In order to meet the urgent need, quantitative correlation analysis(QCA) is proposed to analyse and compare the performances of different fusion methods directly from data before and after fusion. Experiment results show that the new method is effective and the results of comparison are in agreement with the results of application.

Analysis of the Influence Factors of Grain Supply-Demand Gap in China

Based on the analysis of the grain supply and demand gap’s current situation in China, this paper establishes an indicator system for the influence factors of grain supply and demand gap. Then this paper calculates the correlation degree between the main grain varieties’ supply and demand gap and its influence factors. The results show that sown area and unit yield have the greatest impact on wheat supply and demand gap;per capita disposable income and unit yield have the greatest impact on corn supply and demand gap;per capita disposable income and agricultural mechanization level have the greatest impact on the supply and demand gap of soybean and rice. From the analysis results, we can obtain the difference between the factors affecting the grain supply and demand gap, and provide a certain theoretical basis and new ideas for the balance of grain supply and demand in China.

Quantitative analysis of urban intelligence and ranking the potential of individual initiatives within a designed smart growth plan

Smart growth has been gaining increasing attention among academia and practitioners as a new technology-based solution to meet the city disease challenges.In the research,we mainly accomplish two tasks.One builds an evaluation system to measure the smart growth of a city.And the other develops a growth plan.Firstly,coordination coefficient(C value) model is applied to measure the smart degree.To begin with,we divide the indicators into four aspects which involve five parameters.Then,entropy method is used to calculate the weight of every parameter.After normalizing data of indicators,we set up a smart growth indicator evaluation system.Aiming to assessing the detailed performances,we rank the eight cities according to the score of C value which corresponds to our normal cognition.Secondly,based on Salvo combat model and dynamic trend analysis model,We draw up a 20-year growth plan with a period of 5 years for the two cities we choose.The Salvo model is adopted to describe the dynamic process.Dynamic trend analysis model is introduced to gain the optimum solution and the optimal point in every stage.In addition,compared with the point of every stage,we can obtain the proportion of investment in different stages.Thirdly,to evaluate the sensitivity of our model with the OFAT Method,we adjust the parameters k_1,k_2 and O_(ij) approximately.It comes out that the change of k_1,k_2 and O_(ij) has an impact on the C value.But the sensitivity of k_1,k_2 is higher.Lastly,we analyze the influence caused by population growth.To a certain extent,it can be concluded that the plan we made can alleviate the negative impact of population growth through the analysis of the chart.

基于PCA-Entropy TOPSIS 的甘薯品种块根质构品质评价

【目的】质构品质是甘薯块根品质评价的重要指标,直接影响其鲜食和产后加工。质构品质评价是甘薯综合利用过程和品质育种的重要环节。完善甘薯块根质构品质评价体系,为其利用和育种提供参考。【方法】应用物性分析仪质地多面分析法对45个甘薯品种块根的硬度、黏附性、内聚性、弹性、胶黏性和咀嚼性进行测定,分析各质构参数间的相关性,采用主成分分析确定各个参数权重,并结合TOPSIS法对45个甘薯品种块根的质构品质进行综合评价。【结果】45个甘薯品种的质构参数均有一定差异,咀嚼性和黏附性变异系数较大,分别为35.23%和49.15%。咀嚼性变化范围为60.30—284.66 N,平均为149.29 N,浙薯13的咀嚼性最大,为284.66 N,166-7和龙薯14的咀嚼性较小,分别为60.30和77.28 N;黏附性变化范围为-10.4—-0.80 J,平均为-4.71 J,龙薯31的黏附性最大,为-1.34 J,冀紫薯2号和普薯32的黏附性较小,分别为-9.34和-10.40 J。内聚性和弹性的变异系数较小,分别为14.27%和15.75%。内聚性变化范围为0.15—0.28,平均为0.21,商薯19的内聚性最大,为0.28,红皮白心的内聚性最小,为0.15;弹性变化范围为5.01—8.93 mm,平均为6.59 mm,西农431的弹性最大,为8.93 mm,166-7的弹性最小,为5.01 mm。胶黏性变异系数为23.84%,变化范围为11.97—32.78 N,平均为22.20 N,普薯32的胶黏性最大,为32.78 N,166-7的胶黏性最小,为11.97 N;硬度变异系数为19.47%,变化范围为59.79—143.41 N,平均为105 N,绵粉1号、商徐紫1号和苏薯29的块根硬度大于140.00 N,166-7的块根硬度最小,为59.79 N。相关性分析表明,块根硬度与胶黏性、咀嚼性均呈极显著正相关,胶黏性与咀嚼性呈极显著正相关,内聚性与弹性、胶黏性、咀嚼性均呈极显著正相关,弹性与胶黏性、咀嚼性均呈极显著正相关。6个质构参数经主成分分析,被提取的3个主成分累计方差贡献率达94.674%,硬度、黏附性、内聚性、弹性、胶黏性和咀嚼性的权重分别为0.121、0.161、0.102、0.232、0.162和0.223。【结论】明确了淀粉型甘薯质构品质优良的品种为龙薯31、商薯19和冀薯982;鲜食型甘薯质构品质优良的品种为苏薯16、紫罗兰和徐薯32。

Upper Estimates on the Higher-dimensional Multifractal Spectrum of Local Entropy

We discuss the problem of higher-dimensional multifractal spectrum of local entropy for arbitrary invariant measures. By utilizing characteristics of a dynamical system, namely, higher-dimensional entropy capacities and higher-dimensional correlation entropies, we obtain three upper estimates on the hlgher-dimensional multifractal spectrum of local entropies. We also study the domain of higher-dimensional multifractai spetrum of entropies.

Practical Method of Estimating Standard Entropies of Cations in Solid Compounds

The standard entropy Sm of the cation in solid compound is represented by using the greatest principal quantum number (n) and electron number (m) of the highest energy level group in ground state atom. There is a high correlativity between Sm and n, m, with the coefficient of multiple correlation being 0. 993. The binary linear regres siou equation Sm = 8. 58+ 8. 03n+ 0. 33m is built up by the least square method, and proved highly effective by the F test under the significance level a= 0. 01. The correlativity between Sm and m increases with the increase of n.

基于Entropy-Kmeans++的尾矿库安全风险分级预警模型

针对尾矿库安全监管难度大、安全防范意识不足的问题,提出了一种基于Entropy-Kmeans++的尾矿库安全风险分级预警模型。首先,以某尾矿库为例,根据尾矿库现状确定威胁尾矿库安全的主要因素,建立适用于该尾矿库的评价指标体系;其次,运用熵权法(Entropymethod)获取各指标对应的权重信息,得到各个数据点的风险综合评分;接着,采用Kmeans++算法对风险评价结果进行聚类,得到风险评价结果的划分等级。最后运用该模型确定每个数据点对应的风险等级。结果表明:尾矿库安全风险分为低风险、较低风险、中风险、较高风险、高风险5类,该模型的评价结果与该尾矿库的实际安全情况一致,能够有效对该尾矿库的安全风险进行预警。

家庭养老能力评价指标体系构建与实证分析

家庭养老能力事关社会养老服务需求与发展,亟需构建科学有效的家庭养老能力评价指标体系。文章利用CHARLS2018年调查数据,构建出由自我养老能力、配偶养老能力和子女养老能力组成的3个准则指标,共有9个子准则指标和17个观测指标构成的家庭养老能力综合评价指标体系。采用熵权法和复相关系数法确定指标权重,并运用U检验、H检验和空间相关性分析家庭养老能力及其分维度的分布特征。结果显示:子女养老能力、自我养老能力和配偶养老能力权重系数分别为0.555、0.288和0.157。家庭养老能力的得分为0.433±0.091,子女养老能力、自我养老能力和配偶养老能力分维度得分分别为0.121±0.056、0.066±0.019和0.245±0.069,均呈现右偏分布,子女养老能力维度失分最多,自我养老能力维度差异性最大。女性、农村和西部地区老人的家庭养老能力显著弱于男性、城市和东部地区老人。低龄老人自我养老能力和配偶养老能力显著较高,但子女养老能力也显著低于高龄老人。中国家庭养老能力居前三位的是上海市、北京市和新疆维吾尔自治区,云南省、甘肃省和安徽省居后三位。研究发现中国家庭养老能力总体得分不高,自我养老能力与子女养老能力之间呈现“互补”态势。家庭养老能力分布呈现性别、城乡和区域差异性。养老服务体系需基于当前家庭养老能力及其分维度的地区差异性,因地制宜发展。

降速方式对混流泵压力脉动特性的影响

混流泵在降速过程中的内部流动特性变化对其性能和稳定性有重要影响。针对这一问题,该研究探究了混流泵在降速过程中内部流动的复杂性,尤其关注不同降速方式对泵内压力脉动特性的影响。通过构建多通道测试系统,收集了混流泵在不同降速方式下的外特性参数信号和泵内压力脉动信号。并采用非稳态信号处理技术,从时域、频域和时频三方面探究不同降速方式对叶轮出口和导叶内部的压力脉动特性的影响以及二者之间的相关性。结果表明,泵内压力脉动的峰值和样本熵的变化趋势与不同降速方式的幂指数呈正相关关系;在整个降速过程中叶轮出口压力脉动对导叶内压力脉动起主导作用;叶轮出口和导叶内部压力脉动之间的相干频率主要集中于80~120 Hz之间;在不同降速过程中叶轮出口和导叶内部的压力脉动之间强相关区域的频带范围保持不变,但是强相关区域在整个降速过程频带范围中的占比有所变化;对于具有固定初始转速和目标转速的降速过程,降速方式的改变不会影响叶轮出口和导叶内压力脉动的相干频率。研究结论可为揭示混流泵瞬态运行特性及提高混流泵降速运行中的稳定性提供参考。

基于灰色关联-熵权法的座体注塑工艺参数优化

手持风扇底座具有复杂曲面与多筋结构等复杂的结构特征,这阻碍了材料的流动,可能会使产品产生熔接线、翘曲、体积收缩等缺陷,进而影响产品的表面质量和尺寸精度。为解决上述问题,通过理论算法与有限元仿真相结合开展风扇底座注塑工艺参数的优化研究。首先,根据产品特征确定了型腔数量及浇口位置,初步分析发现产品的缩痕指数相对较大;其次,以翘曲变形和缩痕指数为优化目标,建立中心复合试验方案并开展仿真分析,结合灰色关联与熵权法进行多目标优化,确定了工艺参数对灰色关联度影响的大小程度,依次为熔体温度、模具温度、注射时间、保压压力及保压时间;最后,确定最佳工艺参数组合为熔体温度225℃、模具温度30℃、注射时间5 s、保压压力20 MPa及保压时间30 s。相比初始方案,最佳工艺参数组合下的缩痕指数降低了30.79%,由于加强筋的存在翘曲变形优化前后相差较小。

基于生命周期法的生鲜农产品冷链物流绿色度评价

随着国家节能减排政策的深入,生鲜冷链作为能耗较高的物流产业,其绿色性引起了人们的重视。文章基于生鲜农产品冷链物流的全生命周期分析其各阶段的绿色性,以各阶段碳排放量和资源利用率为指标建立绿色度评价体系,并以番茄为例,基于生命周期法的计算数值,采用熵权法进行权重计算,进而用灰色关联度法进行绿色度评价。评价结果表明,生鲜农产品运输过程的损耗是对绿色度影响最大的因素,其次是车辆的能源利用率和货物的实载率。另外,水路运输的碳排放量远低于公路运输,但受限于地理条件和运输时间。针对评价结果,给出了提高生鲜农产品冷链物流绿色度的建议,为减少碳排放量提供了改进方向。

中国绿色低碳发展的水平测度与空间关联效应研究——基于社会网络分析法

基于绿色低碳发展的理论内涵,从绿色效益、低碳效益和经济效益三个维度构建绿色低碳发展评价指标体系,利用熵值法测度绿色低碳发展指数,并运用Dagum基尼系数和社会网络分析法考察中国绿色低碳发展的时序演变特征与空间关联关系。研究表明,2011—2021年中国绿色低碳发展水平在低位保持稳步上升态势,且东部地区绿色低碳发展水平高于全国平均水平,更远超中西部地区;其Dagum基尼系数呈现先下降后平稳的趋势,表明中国绿色低碳发展水平的区域差异逐渐减小并趋于协调;中国省际绿色低碳发展的空间关联关系较强,且具有稳定性,但仍有提升的空间。

4种薯类食品多项指标的灰色模式识别分析

选择我国不同地区红薯、山药、葛根、紫薯4种薯类食品作为研究对象,对食品多指标测定与综合评价.从燃烧热、燃烧稳定性、脂肪、灰分、粗纤维含量方面评价食品营养.测定4种食品燃烧热、燃烧稳定性、脂肪、灰分及粗纤维含量,并从食品营养方面用化学计量方法进行质量评价与分类.结果表明,4种薯类食品燃烧热大小顺序为:葛根>红薯>山药>紫薯,燃烧稳定性排序为:山药>葛根>紫薯>红薯,脂肪含量顺序为:葛根>紫薯>红薯>山药,灰分含量顺序为:葛根>山药>红薯>紫薯,粗纤维含量顺序为:紫薯>山药>葛根>红薯,多指标化学计量分析顺序为:山药>葛根>紫薯>红薯.这项研究为热重分析方法研究食品燃烧稳定性评价与研究提供理论支持,这项研究建立的多指标综合评价体系为食品营养评价提供一种新思路,这项研究为大规模开发食品资源以及食品分类研究提供有力地科学依据.

我国粮食安全水平测度及影响因素研究——基于2012—2022年31个省级面板数据

基于中国2012—2022年31个省区市面板数据,综合采用全局熵值法、TOPSIS距离函数法和灰色关联分析法,实证研究了中国粮食安全水平及影响因素。研究结果显示,2012—2022年我国大部分省区市粮食安全水平呈先下降后上升的趋势。从分维度指标综合指数的时间演化趋势来看,大部分省份的粮食供给安全、粮食生产稳定性安全、粮食生产持续性安全维度综合指数呈上升趋势,粮食生产持续性安全维度综合指数的变动较大。灰色关联分析结果显示,单位面积产量、耕地面积比例、农业机械总动力、人均粮食占有量、粮食生产波动系数等因素与粮食安全水平关联度较大。未来,应增强耕地生产能力,确保耕地面积的基本稳定;加强农业基础设施建设,持续提升粮食供给保障能力;促进农业产业化发展,优化粮食生产结构和布局;加强农业风险管理,推动农业科技创新和应用。

乡村振兴背景下甘肃农村物流发展策略研究——基于灰色关联分析和熵权法

在乡村振兴战略的背景下,甘肃省作为国家重点扶持的农业大省,其农村物流发展面临着更高的要求和标准。文章以灰色关联分析和熵权法构建的区域物流发展水平指标体系为基础,选取了甘肃省、山东省、河南省和黑龙江省作为研究对象,在2012—2021年10年数据的基础上,对农村物流发展水平进行了测度。实证结果表明:在国家和省的政策支持下,近年来甘肃农村物流发展取得了显著成效,但与其他省份相比仍存在一定差距。从时间和空间的多重维度印证了评价指标体系的有效性和科学性。最后根据数据和结果分析提出针对性的政策建议,以期促进甘肃省农村物流的发展。

Spatiotemporal evolution and influencing factors of urban resilience in the Yellow River Basin,China

The Yellow River Basin of China is a key region that contains myriad interactions between human activities and natural environment.Industrialization and urbanization promote social-economic development,but they also have generated a series of environmental and ecological issues in this basin.Previous researches have evaluated urban resilience at the national,regional,urban agglomeration,city,and prefecture levels,but not at the watershed level.To address this research gap and elevate the Yellow River Basin’s urban resilience level,we constructed an urban resilience evaluation index system from five dimensions:industrial resilience,social resilience,environmental resilience,technological resilience,and organizational resilience.The entropy weight method was used to comprehensively evaluate urban resilience in the Yellow River Basin.The exploratory spatial data analysis method was employed to study the spatiotemporal differences in urban resilience in the Yellow River Basin in 2010,2015,and 2020.Furthermore,the grey correlation analysis method was utilized to explore the influencing factors of these differences.The results of this study are as follows:(1)the overall level of urban resilience in the Yellow River Basin was relatively low but showed an increasing trend during 2010–2015,and significant spatial distribution differences were observed,with a higher resilience level in the eastern region and a low-medium resilience level in the western region;(2)the differences in urban resilience were noticeable,with industrial resilience and social resilience being relatively highly developed,whereas organizational resilience and environmental resilience were relatively weak;and(3)the correlation ranking of resilience influencing factors was as follows:science and technology level>administrative power>openness>market forces.This research can provide a basis for improving the resilience level of cities in the Yellow River Basin and contribute to the high-quality development of the region.

新疆数字经济发展水平的多维测度及预测——基于熵值法和灰色关联分析法

文章基于2013—2021年新疆数字经济发展的相关面板数据,从经济发展水平、数字通信基础设施、社会创新能力、企业电子化水平四个维度,构建起新疆数字经济发展综合水平的评价指标体系,并通过熵值法测算各个指标的权重,进而对2013—2021年新疆数字经济发展水平进行综合评价。此外,采用灰色关联分析法探讨各个子系统与新疆数字经济发展之间的关联性,同时利用GM(1,1)灰色预测模型,对短期新疆数字经济发展的总体趋势进行预测。结果表明:新疆数字经济发展水平总体呈逐年提升的时序特征,从各准则层看,数字通信基础设施提升幅度最大,而社会创新能力不足;根据关联度测算结果可知,经济发展水平对数字经济发展的影响较为显著,社会创新能力仍是新疆发展数字经济的短板,但未来新疆数字经济的发展仍有很大潜力。

基于兴趣点数据和最大熵模型的苏州市鸟类多样性研究

鸟类群落对于城市环境中的食物及栖息地有较强的依赖性,导致城市鸟类与环境因子的关系非常密切。以苏州市为研究区域,提取影响城市鸟类生存繁衍的关键环境因子,探索性地引入兴趣点(point of interest,POI)数据并构建多类别POI核密度指数,揭示苏州市不同城市空间布局对鸟类分布的影响。通过收集苏州市2020—2022年鸟类分布数据,利用最大熵模型(maximum entropy model,MaxEnt),对205种鸟类在苏州范围内的潜在适生区进行模拟,分析了苏州市鸟类多样性的空间分布格局及热点地区。结果显示,MaxEnt模型预测结果可信度较高(AUC平均值为0.854);土地利用类型、归一化植被指数和距离绿地距离是影响苏州市鸟类空间分布的主要环境变量,林鸟与水鸟的差异影响因子主要为冠层高度和距离水源距离;结合偏相关分析得出,在12类POI核密度因子中,乡村住宅用地类型对于鸟类的分布影响最大,这表明在城市发展的同时也需要注重维持乡村生态平衡。