Weighted Multi-sensor Data Level Fusion Method of Vibration Signal Based on Correlation Function

As the differences of sensor＇s precision and some random factors are difficult to control,the actual measurement signals are far from the target signals that affect the reliability and precision of rotating machinery fault diagnosis.The traditional signal processing methods,such as classical inference and weighted averaging algorithm usually lack dynamic adaptability that is easy for trends to cause the faults to be misjudged or left out.To enhance the measuring veracity and precision of vibration signal in rotary machine multi-sensor vibration signal fault diagnosis,a novel data level fusion approach is presented on the basis of correlation function analysis to fast determine the weighted value of multi-sensor vibration signals.The approach doesn＇t require knowing the prior information about sensors,and the weighted value of sensors can be confirmed depending on the correlation measure of real-time data tested in the data level fusion process.It gives greater weighted value to the greater correlation measure of sensor signals,and vice versa.The approach can effectively suppress large errors and even can still fuse data in the case of sensor failures because it takes full advantage of sensor＇s own-information to determine the weighted value.Moreover,it has good performance of anti-jamming due to the correlation measures between noise and effective signals are usually small.Through the simulation of typical signal collected from multi-sensors,the comparative analysis of dynamic adaptability and fault tolerance between the proposed approach and traditional weighted averaging approach is taken.Finally,the rotor dynamics and integrated fault simulator is taken as an example to verify the feasibility and advantages of the proposed approach,it is shown that the multi-sensor data level fusion based on correlation function weighted approach is better than the traditional weighted average approach with respect to fusion precision and dynamic adaptability.Meantime,the approach is adaptable and easy to use,can be applied to other areas of vibration measurement.

基于ε-level蝙蝠算法的无人机三维航迹规划

针对复杂地形环境、存在各种威胁和约束的无人机航迹规划问题,提出了一种基于ε-level改进蝙蝠算法的航迹规划算法。根据无人机目标函数和约束条件,建立无人机三维航迹规划模型;其次,针对蝙蝠算法处理高维带约束问题存在的早熟现象,设计了自适应权重系数和迭代阈值以平衡算法的探索能力和开发能力,并结合ε-level比较策略提高算法对非凸非线性约束优化问题的处理能力;设计了转弯半径可变的Dubins曲线用来对航迹进行平滑处理并解决2个航迹点连线贯穿地形的问题。通过仿真实验,并与蝙蝠算法、粒子群优化算法、ε-level粒子群优化算法和ε-level差分进化算法相比较,所提算法在开发能力、稳定性和成功率等方面都表现出较优的性能。

Contour tracking using weighted structure tensor based variational level set

A novel contour tracking method using weighted structure tensor based variational level set is proposed in this paper.The image is first converted to weighted structure tensor field by extracting apositive definite symmetric covariance matrix for each pixel.Then,a level set method is employed to represent object contour implicitly which separates the image domain into two areas each modeled by tensor field based Gaussian mixture model separately.By solving agradient flow equation of energy functional with respect to the level set,the object contour will converge to its real profile in the newly arrived frame.Experimental results on several video sequences demonstrate the better performance of our method than the other two contour tracking algorithms.

A Simple Weighted Integration Method for Calculating Surface Tension Force to Suppress Parasitic Flow in the Level Set Approach

Parasitic flows may occur in the numerical simulation of incompressible multiphase flow due to errors in the calculation of surface tension terms, specifically for the curvature and unit normal vector. An improved method for calculating the surface tension based on the level set approach is proposed, in which the contribution of not only the center node but also the rest area of a control volume to the calculation of surface tension is considered in a balanced manner. The weighted integration method (WIM) is more consistent with the concept of a banded in- terface in the level set method. It is applied to the temporal evolution of a two-dimensional neutrally buoyant liquid drop and a buoyancy driven deformable bubble in an immiscible fluid for the validation of WIM. The results show that the parasitic flows are evidently suppressed by the weighted integration method. The weight factors for WIM in 3-D cases are also suggested.

Addressing the public health concerns of physical inactivity, low levels of fitness, and unhealthy weight among Chinese school-aged children

In China, sports and physical activity （PA） have tradition- ally been an integral part of school curricula to promote fitness and enhance healthy growth among children and ado- lescents. Three decades of economic reforms, however, have brought major changes in social, economic.

Level Set追踪等温非牛顿熔体前沿界面

应用Level Set方法追踪薄壁型腔内Hele-Shaw熔体流动前沿界面,采用5阶加权本质无振荡格式耦合中心差分格式实现了充填阶段的动态模拟．准确追踪到了不同时刻熔体前沿界面,并得到了对应的压力等值线分布,数值结果表明Level Set方法是准确追踪注塑成型熔体前沿界面的一种行之有效的方法．

Effects of Different Nitrogen Fertilizer Levels on Lodging and Yield of Rice

[Objective] This study aimed to investigate the effects of different fertilizer levels on lodging and yield of rice. [Method] A total of four treatments were designed and applied with 6, 9, 12 and 15 kg of nitrogen fertilizer, respectively. After seedling transplanting, the biological characteristics of rice at different growth stages in each treatment and the biological and economic characteristics of rice after lodging were determined for statistical analysis. [Result] Application with 15 kg of nitrogen fertilizer had significant promotion effect on the increase of rice yield; compared with the control (6 kg of nitrogen fertilizer), rice yield in three experimental treatments (9, 12 and 15 kg of nitrogen fertilizer, respectively) increased by 50.74%, 89.11% and 94.48%, respectively; lodging-resistance mechanical strengths of the three experimental treatments were 103.97%, 132.01% and 89.83% of the control, respectively; rice lodging resistance of treatment C (12 kg of nitrogen fertilizer) was the strongest, with the highest yield. [Conclusion] This study provides reference data and technical support for the rational fertilization of rice production.

Loudness Summation and Weightings for Loudness and Environmental Noise Assessment

A stationary loudness model has been built up on the basis of the former ISO 226: 1987 concerning equal-loudness-level contours. The loudness and loudness level expressions derived in the study include the same parameters as used when determining the equal-loudness-level contours of the former ISO standard. However, as an additional main idea, a loudness summation rule has been proposed in the study. Moreover, the loudness expressions have been normalised to give the same values for people who have a similar sense of hearing. It has also been found that the loudness expressions include basically two different weightings. The first weighting is a conservative frequency weighting in the domain of sound pressure level, and the second weighting consists of coefficients applied to the weighted sound pressure levels. The latter have the greatest effect on the very low-frequency range. Finally, the paper includes a new way to use the A-weighting which takes into account the compressed character of the equal-loudness-level contours at the low frequency range. This method remarkably transforms the character of the A-weighting as a measure for low-frequency environmental noise.

Influence of Family Status on the Dietary Patterns and Nutritional Levels of Children

A diversity of socio economic and cultural factors contributes towards maintenance and changes in dietary patterns of people. Therefore People around the world have adapted different types of dietary patterns for their survival. Aim of this study was to investigate the most relevant factors influencing human dietary patterns. Sample for the study was selected by using the Stratified sampling technique, which consists of 390 families residing around the Abatenna estate, Bandarawela municipal council, Sri Lanka. Principal component analysis techniques and correlation analysis were employed to identify the most relevant factors which affect human dietary patterns. Results of the study indicate that socio economic conditions, monthly income, number of children in a family, dietary patterns and weight-related behaviors are highly co-related with each other. These findings suggest that education and awareness programs on nutrition should target low income groups to enhance their knowledge on dietary patterns.

基于灰色系统理论的电网工程绿色建造模糊综合评价模型

为贯彻落实绿色发展理念,提升现有电网工程绿色建造评价方法的全面性、系统性以及客观性,提出了一种基于灰色系统理论的模糊综合评价模型。通过研究影响电网工程设计、施工与交付等环节的重要绿色评价因子,构建了多层次的绿色建造评价指标体系。并基于灰色系统理论确定指标权重,建立了多层级模糊综合评价模型。同时选取电网工程案例来进行验证,证明了该模型能够科学、合理地确定各指标的权重,从而为电网工程绿色建造评价及不断优化提供了支撑。

基于CRITIC-加权灰色关联分析的年度洪涝灾情评估模型及应用

洪涝灾情评估能够直观呈现洪涝灾害强度和破坏程度,准确评估洪涝灾情是有针对性开展防洪减灾工作的基础。为充分表征洪涝灾害范围及深度,基于洪涝灾害的主要承灾体,从人口受灾、农作物受灾、房屋倒损、水利防洪设施损坏和经济损失5个洪涝灾害主要影响层面筛选洪涝灾情评估指标,分目标层、因子层、指标层构建全国及各地区年度洪涝灾情评估指标体系;基于年度洪涝灾害等级和年度洪涝灾害综合损失程度评估年度洪涝灾情,通过耦合CRITIC权重法和灰色关联分析模型构建CRITIC-加权灰色关联分析模型进行年度洪涝灾害等级评估,采用灾情指数法进行年度洪涝灾害综合损失程度评估;基于ArcGIS直观呈现空间数据的优势,将各地区年度洪涝灾害等级及综合损失程度采用区划图的形式展现。基于以上方法对2006-2021年全国及各地区进行年度洪涝灾情评估,结果表明:在全国年度洪涝灾情评估结果中,2010年为特大洪涝灾害,2013年和2016年为重大洪涝灾害;在各地区年度洪涝灾情评估结果中,湖南省2006年和2017年、河南省2021年年度洪涝灾害等级达到特大洪涝灾害;历年洪涝灾情较重且灾情频次较高的省份依次是四川省、湖南、湖北、江西、广东、海南;基于CRITIC-加权灰色关联分析模型和灾情指数法的年度洪涝灾情评估结果,可作为地区开展防洪减灾工作的依据。

肥胖患者情绪异常与减重手术效果的相关性

背景减重手术是治疗肥胖的重要手段之一,部分拟行减重手术的患者存在异常的情绪及较高的外周血炎症因子水平,可能会影响减重手术效果。目前国内对于该群体术前情绪状态和外周血炎症因子水平与减重手术效果相关性的研究有限。目的探讨术前情绪异常与肥胖患者减重手术效果的相关性,以期为提高患者减重手术的效果提供参考。方法纳入2022年12月30日—2023年6月30日,于四川大学华西医院胃肠外科住院的、拟行减重手术的肥胖患者81例,采用汉密尔顿抑郁量表17项版(HAMD-17)和汉密尔顿焦虑量表(HAMA)评定患者的情绪状态,将HAMD-17或HAMA评分≥7分或有抑郁或焦虑障碍史的患者纳入情绪异常组(n=34),将HAMD-17与HAMA评分均<7分且无上述既往史的患者纳入不伴情绪异常组(n=47)。采用自制问卷收集一般资料,采用贝克自杀意念量表中文版(BSI-CV)、进食障碍调查问卷(EDI)以及匹兹堡睡眠质量指数量表(PSQI)分别评定自杀意念、进食及睡眠情况;检测两组患者外周血C反应蛋白(CRP)和白细胞介素-6(IL-6)水平。术后1个月和术后6个月通过门诊或电话随访收集患者当日清晨空腹体质量和身高。采用Pearson相关分析考查BMI与患者术前HAMD-17总评分及外周血炎症因子水平之间的相关性。结果最终共62例肥胖患者完成本研究,其中情绪异常组27例、不伴情绪异常组35例。情绪异常组最近一周和最抑郁时的BSI-CV评分、EDI总评分、PSQI总评分、外周血CRP及IL-6水平均高于不伴情绪异常组(Z=2.677、2.975,t=3.573、4.035、1.990、2.799,P<0.05或0.01)。两组BMI的组别效应及组别与时间的交互效应均无统计学意义(P均>0.05),时间效应有统计学意义(F=227.740,P<0.01)。情绪异常组基线期、术后1个月以及术后6个月的BMI与IL-6水平均呈正相关(r=0.419、0.510、0.559,P<0.05或0.01),术后6个月的BMI与HAMD-17总评分呈正相关(r=0.390,P<0.05),术后6个月ΔBMI%与HAMD-17总评分呈负相关(r=-0.421,P<0.05)。不伴情绪异常组基线期BMI与IL-6水平呈正相关(r=0.338,P<0.01)。结论伴或不伴情绪异常的肥胖患者行减重手术的短期效果可能一致,减重手术的效果可能与术前抑郁情绪严重程度无关。

“专精特新”企业群体发展对增强我国关键产业链韧性的效应

党的二十届三中全会强调,健全提升产业链供应链韧性和安全水平制度。研究“专精特新”企业群体发展影响产业链韧性的作用效果和机制,有助于精准制定产业政策,促进产业链韧性水平提升。通过模型推导和实证检验,在产业链韧性视角下研究“专精特新”企业群体的强链效应,发现“专精特新”企业的专业化程度、精细化程度、特色化程度和新颖化程度提升,能够显著提升产业链韧性,且该结论通过了替换核心变量、固定行业效应和调整观测期间的稳健性检验。进一步分析发现,随着“专精特新”企业的技术水平更高、资源禀赋更强和价格加权水平更低,其对产业链韧性的提升效果更强。

考虑保供电需求的光储微电网优化配置及电能质量评估

针对用户日益迫切的保供电需求以及光伏出力与负荷用电的随机性、波动性引发的电能质量的问题,建立了考虑保供电需求的光储微电网双层优化模型,并对规划配置的微电网电能质量进行评估。该模型以等效净负荷标准差和弃光率最小为上层优化目标,以微电网有功功率损耗最小为下层优化目标,以储能满足保供电负荷的保供电需求作为附加约束条件,采用遗传算法求解。然后设计源、网、荷三类指标,采用组合赋权法确定各指标权重,实现对微电网电能质量的综合评估。最后以改进的IEEE-33系统验证了所提模型的有效性。结果表明考虑保供电需求后能够提高微电网电能质量,并在一定范围内保供电负荷越大时越能提高微电网电能质量和用户满意度。

群众体育发展水平测度及多重影响因素的组态分析

群众体育发展关乎体育强国和健康中国建设,探究群众体育发展水平及其影响因素对我国体育建设具有重要意义。基于我国31个省(自治区、直辖市)2019年的数据,运用熵权法测算群众体育发展水平,再运用模糊集定性比较分析法(fsQCA)对群众体育发展的影响因素进行组态分析。结果表明:(1)我国群众体育发展水平普遍较低,且发展水平由东向西呈下降趋势;(2)政府、社会组织和市场三者缺乏横向联动,尤其是市场发挥作用微弱。为此建议:(1)群众体育水平的提高要重视体育机会、体育资源、体育权利和体育能力的发展;(2)在体育建设过程中,应加强政府、社会组织和市场的横向联动,尤其要促进市场发挥核心作用。

乡村振兴战略下陕西省农村物流发展水平测度与路径研究

发展农村物流是推进乡村振兴的重要举措,陕西省作为西北地区的农业大省,近年来持续加大交通基础设施建设力度,完善县乡村三级物流体系,积极培育农村物流服务品牌,但依然存在物流基础设施建设相对滞后、物流资源缺乏深度整合、物流服务标准化不足、数字技术应用水平稍显薄弱等问题。在深入分析发展现状和短板的基础上,选取基于熵权的TOPSIS评价方法,从经济发展、物流规模、基础设施、信息化程度四个维度评估市级、县级两个层面农村物流发展状况,进一步探究农村物流发展的难点与路径,并提出优化服务网络功能,完善物流基础设施布局、提高资源利用效率,深化多点融合模式、完善监管服务体系,提高农村物流服务标准等发展路径,更加高效地推动陕西农村物流的发展。

基于维纳滤波的风电机组齿轮箱轴承故障诊断

存在轴承故障时,风电机组齿轮箱振动信号的幅度与频率都会发生明显改变,通过信号变化行为的测量能够判定出具体的轴承故障等级。为实现对轴承故障的准确判定,设计基于维纳滤波的风电机组齿轮箱轴承故障等级判定方法。通过获取轴承振动波的IMF分量,并完善维纳滤波算法,在此基础上,处理故障数据,实现基于维纳滤波的轴承故障特征提取。定义轴承故障特征的伪四阶矩,通过求解特征角度的方式,确定故障等级基准的判定范围,完成基于维纳滤波的风电机组齿轮箱轴承故障等级判定方法的设计。实验结果表明,利用上述方法,能够根据幅度和频率的变化行为,判定风电机组齿轮箱轴承的故障等级,符合实际应用需求。

上海市高程基准近五年变化分析

高程基准是一个地区经济社会发展的重要基础设施。上海市于2020—2022年开展了全市高程基准更新工作。通过对原有高程基准基础设施调查、高程控制网水准复测、高程基准分析三步工作完成了上海市的高程基准的更新并发布新一期的高程基准成果。为了掌握上海市高程基准在近5 a的变化情况,对上海市城市水准点的数量变化、区域分布及高程变化情况3个方面进行研究分析,得出了关于上海市城市水准点数量、分布及高程变化的有益结论。最后对上海市高程基准的维护更新提出了一些建议。

属性权重动态更新的自适应群体共识决策方法

为了提高不确定语言环境下异构多属性群决策的质量、效率及可解释性,提出一种属性权重动态更新的自适应群体共识决策方法。首先,定义不确定语言变量与中间值之间的转换函数,发展多级共识测度,建立计算属性初始权重的双目标优化模型;进而,构建包含群体共识自动达成规则和属性权重动态更新机制的自适应共识模型,实现待调整值的精准定位和自动修改,在优化属性权重的同时进一步提升群体共识水平;然后,对于达成共识的群体决策矩阵,先利用转换函数将中间值转换为不确定语言变量,再使用属性权重和集结算子得到各方案的综合评价结果;最后,通过供应商选择实例和实验比较分析验证所提方法的有效性和可行性。本文研究结果为灵活、高效地求解复杂环境下的多属性群决策问题提供了有效途径。

饲料蛋白质水平对中国结鱼幼鱼生长性能、饲料利用、体组成及消化酶活性的影响

试验旨在探究不同蛋白质水平饲料对中国结鱼幼鱼的影响。选择体重(3.26±0.09)g健康的试验鱼720尾,随机分为6组,每组3个重复,每个重复40尾,分别饲喂蛋白质水平为33.19%、36.48%、39.80%、42.59%、45.80%、48.06%的试验饲料。试验期10 w。结果显示,随着饲料蛋白质水平的升高,试验鱼增重率和特定生长率均在45.80%组达到最大,显著高于33.19%组、36.48%组和39.80%组(P<0.05);45.80%组试验鱼终末体长显著高于其余各组(P<0.05)。33.19%组饲料系数显著高于39.80%组、42.59%组和48.06%组(P<0.05)。42.59%组全鱼和肌肉的粗蛋白含量均最高,其中全鱼粗蛋白含量显著高于其余各组(P<0.05)。42.59%组试验鱼胰蛋白酶活性最高,显著高于其余各组(P<0.05)。45.80%组肠道脂肪酶活性较高,显著高于33.19%组、36.48%组、39.80%组和42.59%组(P<0.05)。33.19%组肠道α-淀粉酶活性较高,显著高于39.80%组、42.59%组、45.80%组和48.06%组(P<0.05)。研究表明,经折线模型及二次非线性模型回归分析,中国结鱼幼鱼饲料适宜蛋白质水平以41.65%~43.53%为宜。