Regional Differences and Optimal Allocation of Cultivated Land Utilization Benefits Based on Improved TOPSIS Method:A Case Study of Guangxi

Taking 14 prefecture-level cities in Guangxi as an object,this paper explored the difference of cultivated land utilization efficiency in Guangxi,comprehensively evaluated the economic,social,and ecological aspects,and analyzed the regional differences in cultivated land use efficiency in Guangxi from 2005 to 2018 based on the improved TOPSIS method.By studying the quantitative change trends and spatial differences of the utilization benefit of cultivated land resources in Guangxi,it came up with recommendations for optimizing the allocation of cultivated land from the quantity and quality of cultivated land.It is intended to provide a scientific and theoretical reference for improving the use efficiency of cultivated land in Guangxi.

High rate of clinically relevant improvement following anatomical total shoulder arthroplasty for glenohumeral osteoarthritis

BACKGROUND The minimal clinically important difference(MCID)is defined as the smallest meaningful change in a health domain that a patient would identify as important.Thus,an improvement that exceeds the MCID can be used to define a successful treatment for the individual patient.AIM To quantify the rate of clinical improvement following anatomical total shoulder arthroplasty for glenohumeral osteoarthritis.METHODS Patients were treated with the Global Unite total shoulder platform arthroplasty between March 2017 and February 2019 at Herlev and Gentofte Hospital,Denmark.The patients were evaluated preoperatively and 3 months,6 months,12 months,and 24 months postoperatively using the Western Ontario Osteoarthritis of the Shoulder index(WOOS),Oxford Shoulder Score(OSS)and Constant-Murley Score(CMS).The rate of clinically relevant improvement was defined as the proportion of patients who had an improvement 24 months postoperatively that exceeded the MCID.Based on previous literature,MCID for WOOS,OSS,and CMS were defined as 12.3,4.3,and 12.8 respectively.RESULTS Forty-nine patients with a Global Unite total shoulder platform arthroplasty were included for the final analysis.Mean age at the time of surgery was 66 years(range 49.0-79.0,SD:8.3)and 65%were women.One patient was revised within the two years follow-up.The mean improvement from the preoperative assessment to the two-year follow-up was 46.1 points[95%confidence interval(95%CI):39.7-53.3,P<0.005]for WOOS,18.2 points(95%CI:15.5-21.0,P<0.005)for OSS and 37.8 points(95%CI:31.5-44.0,P<0.005)for CMS.Two years postoperatively,41 patients(87%)had an improvement in WOOS that exceeded the MCID,45 patients(94%)had an improvement in OSS that exceeded the MCID,and 42 patients(88%)had an improvement in CMS that exceeded the MCID.CONCLUSION Based on three shoulder-specific outcome measures we find that approximately 90%of patients has a clinically relevant improvement.This is a clear message when informing patients about their prognosis.

Improved Boussinesq方程初边值问题解的数值研究

给出Improved Boussinesq方程的隐式有限差分格式,讨论格式的精度和稳定性.给出不同的初边值条件,由数值试验结果看出IBq方程数值解的变化及在一定条件下数值解的爆破现象.

An Improved Splitting Method

In this paper, an improved splitting method, based on the completely square-conservative explicit difference schemes, is established. Not only can the time-direction precision of this method be higher than that of the traditional splitting methods but also can the physical feature of mutual dependence of the fast and the slow stages that are calculated separately and splittingly be kept as well. Moreover, the method owns an universality, it can be generalized to other square-conservative difference schemes, such as the implicit and complete ones and the explicit and instantaneous ones. Good time benefits can be acquired when it is applied in the numerical simulations of the monthly mean currents of the South China Sea.

Simulating Error-Opening of Pressure Relief Valves of a Station on a Continuous Undulating Oil Pipeline with Large Elevation Difference

For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief tanks.Therefore,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief system.This research focuses on a continuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is studied.By OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reconstructing a real accident and making a comparison with the actual accident data.The maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the station.The accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident data.On this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent valve.The discharge velocity is found to be over the maximum velocity allowed for safety consideration.According to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve occurs.Also it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief valves.From these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operated valves,and employing security control interlock protection program are improvement measures to guarantee safe,efficient and reliable operation of the pressure relief system at B station.

广义Improved KdV方程的守恒差分算法及其收敛性分析

对广义Improved KdV方程的初边值问题进行了数值研究,提出了一个在空间层带有加权系数的两层非线性有限差分格式,该格式合理地模拟了方程本身具有的两个守恒律,并在其差分解的先验估计的基础上利用能量方法分析了该格式的二阶收敛性与无条件稳定性.

考虑载客状态的改进孤立森林浮动车异常数据检测算法

为提高浮动车数据中异常数据检测能力及不同载客状态下的模型检测分析能力,提出基于S-DTA-IIForest(Summation&Difference Third Order Average&Improvement-Isolation Forest)的浮动车数据异常检测算法。构建由相邻两项求和(S)、三阶求和平均差分(DTA)的二维度空间SDTA特征向量;提出差额累计更新和动态区分辨识的改进孤立森林IIForest算法,通过设置停止阈值参数,避免当出现新样本异常值分数大于停止阈值时,仅更新样本不更新孤立森林模型的问题,设计每个二叉树区分辨识度参数,区分辨识度位于停止区间时停止二叉树生长,提高算法收敛性能,以ROC(Receiver Operating Characteristic)曲线下面积AUC(Area Under ROC Cure)、F1-score为指标对模型精度进行对比分析,并以重庆市中心城区学府大道开展实例验证。结果表明:本文S-DTA-IIForest组合算法AUC、F1-score分别为86.63%、0.89,AUC较传统孤立森林IForest(Isolation Forest)提高32.4%,运行效率提高1.29%,具有收敛速度更快、精度更高的优势,载客条件下模型AUC、F1-score较未载客分别提高7.7%、10.8%,组合算法对载客数据有更高的检测精度,且未载客状态数据异常率较载客状态增加71.4%,未载客数据异常率更高。

粮食功能区视角下农业高质量发展水平及区域差异研究

基于2016—2020年省级农业发展数据,综合运用改进后的熵值法、Dagum基尼系数等方法,测算了全国及粮食功能区农业高质量发展水平及差异程度,并进一步从一级指标入手,分析了引起区域差异产生和波动的原因。结果表明:(1)三大粮食功能区的农业高质量发展水平均保持上升趋势,按水平由大到小依次为“主销区、主产区、平衡区”。(2)三大粮食功能区存在区域差异,区域间的差异是总体差异的主要来源,区域内差异也出现不同程度的变动。(3)主销区内部差异波动与产业升级指标相关,主产区内部差异波动主要受产出高效和产业升级指标影响,平衡区内部差异波动源于产业升级指标中的追赶效应。(4)区域间差异主要源自产业升级指标,成果共享指标也起到部分影响作用,三大区域各具发展短板。因此,为提升我国农业高质量发展均衡性,应坚持“因地制宜”原则,以水平最低的平衡区为发力点,以产业升级指标为抓手,以各区域发展短板为突破,采取更具针对性的发展措施。

一种基于改进NLMS的多雷达主瓣干扰抑制方法

远程探测场景下弹载主瓣干扰因与目标角度间隔小,单站抗干扰方法性能下降严重。多雷达通过合理布站可有效“分辨”目标和干扰,被认为是可有效抑制主瓣干扰的途径。针对当前多雷达抗主瓣干扰方法普遍存在收敛速度慢的问题,提出一种基于改进归一化最小均方(NLMS)的多雷达对消抗主瓣干扰方法,并通过理论推导给出了其应用条件。该方法通过定义消散因子实现对步长的自适应控制从而达到快速收敛的目的,仿真结果表明该方法在收敛速度及收敛后均方误差(MSE)上具有明显优势。最后通过外场试验进一步验证该方法的性能,在满足布站条件且干噪比≥30 dB的前提下,信噪比改善可达19 dB以上,具有较高的应用价值。

真空预压与真空井点降水用于软土处理的机理差异

真空预压与真空井点降水两种工艺均可用于软土地基处理,表观上两者都是通过抽真空使土体内孔隙水排出并使软土沉降,但目前对两者的工艺和机理等关键差异的认识不深入,难以有效指导现场施工。真空预压和真空井点降水在抽真空设备、竖向排水通道和密封边界等设备与工艺方面有显著差异;两者的的排水机理也有着本质区别。真空预压的加固机理是负压作用下土体发生塑料排水板水平向排水固结,同时塑料排水板内的水向上流动与重力无关;真空井点降水的加固机理是群井抽水引起地下水位降低,土体的浮重度变为湿重度导致荷载增大使土体沉降,同时井点管内的水向上流动受重力影响。在工艺和机理的差异分析的基础上,进一步明确了真空预压和真空井点降水在10个关键方面的差异,包括加固机理、影响深度、不同深度的真空传播、土体水平变形、竖向排水与重力的关系、抽真空位置影响、与外界是否连通、影响区成因、地下水位变化、是否形成非饱和带。

安徽省财政科技支出效益分析:地区差异与改进路径

优化地方政府财政科技支出效益在提升政府治理效能和推进经济高质量发展方面具有至关重要的作用。文章基于2016—2021年安徽省16个地级市的面板数据,运用DEA-Malmquist模型评估安徽省财政科技支出效益,并运用主成分分析法分析了各地区财政科技明细支出。研究表明:安徽省财政科技支出力度不断加大,效益总体呈上升态势;皖中地区在财政科技支出效益提升方面展现出了显著的潜力和活力;效益提升主要由技术进步以及纯技术效率改进带动,在规模效率改进方面存在着进一步提升的突破口;财政科技明细支出可简并为直接支出、间接支出和事务性支出三大方向。建议地方政府加强科技交流与合作,明确设定财政科技三大支出方向的绩效目标和指标,加强监督管理以确保财政资金使用的有效性。

一种改进型1-3-2压电复合材料的研究

高质量的压电换能器需要具备较高的机电耦合系数和灵敏度。该文在传统型1-3-2压电复合材料的基础上提出了一种改进型1-3-2压电材料,提高了压电换能器的机电耦合系数和换能器的接收灵敏度。通过有限元仿真分析了不同间距对改进型1-3-2压电材料敏感元件的谐振频率、反谐振频率及机电耦合系数的影响,并与传统1-3-2型压电复合材料进行了对比。结果表明,与传统型1-3-2压电复合材料相比,在相同间距条件下,改进型压电材料的机电耦合系数约大0.03。制做的3种不同间距改进型压电材料表明,间距为1 mm的改进型压电材料的机电耦合系数较大,约为0.68。

岩土成层条件下抗滑桩计算的改进有限差分法

滑坡治理工程中抗滑桩可能布置于层状土层、层状岩层,或岩、土成层等各种地质条件下,现行规范对于该问题建议将成层地基按加权平均法换算成等效的当量地基系数,但对于地层差异性较大的岩土成层地基其适用性有待研究。为解决这一问题,基于Euler-Bernoulli梁理论建立抗滑桩受荷段、嵌固段整体受荷分析模型,采用改进有限差分法提出抗滑桩全桩内力求解的统一矩阵运算式,避免常规有限差分方法将桩身分为受荷段和嵌固段及利用滑面处连续性条件求解的复杂迭代过程;基于2个边坡工程抗滑桩治理案例,证明改进有限差分法对岩土成层条件下抗滑桩分析的可靠性,计算用时仅需1.2 s左右,相比已有方法进一步提高抗滑桩分析设计的计算效率。

主被动协同定位空能资源优化配置方法

无人机的快速发展为当今社会带来巨大便利,但其潜在的滥用现象对公共安全构成严重威胁,因此面向无人机的监测与定位技术近年来得到广泛研究。针对远距低飞无人机难以准确定位的应用问题,提出以无源为主、有源为辅的主被动协同定位框架,在基于到达时间差实现无源被动定位的基础上,引入支持往返到达时间测量的有源主动探测设备,择机对无人机进行主动式定位,补偿无源定位缺失的目标高程信息,从而提升无人机的三维定位精度。为充分挖掘主被动的协同定位潜力,文中深入探究无源被动定位节点预先部署的情况下,有源主动定位节点的空域和能域资源的配置方式,推导了主被动协同定位框架下的定位精度衡量指标,构建了空能资源联合优化问题,提出了基于非线性收敛因子和记忆指导的改进灰狼优化的空能资源优化算法。仿真结果表明,针对无人机定位时,主被动协同定位效果优于无源被动定位,典型场景下高程定位精度显著提升约96.33%。此外,所提的空能资源优化算法在求解空能资源联合优化问题时,性能优于标准(传统)灰狼算法、改进灰狼算法等。

基于改进粒子群算法的层合板损伤定量检测方法

针对层合板在加工和服役过程中出现的结构损伤问题,提出基于差分法和改进粒子群算法的两阶段损伤定量检测方法。首先,采用单元弹性模量降低的方法定义了结构损伤单元,通过结构振动特性分析获得了不同损伤工况层合板数值模型的模态参数,运用差分法识别了损伤大致区域。其次,利用改进的粒子群算法定量计算损伤的精确位置和程度。所提算法通过待测结构模型和迭代更新后有限元模型模态参数的柔度矩阵构建目标函数,引入变异因子以使算法有效的跳出局部收敛,MS算子减少了健康单元对真实损伤单元损伤程度的影响。结果表明:基于改进的粒子群算法可精确识别复合材料层合板结构损伤单元的位置和损伤程度。

航空发动机奇数只叶片的风扇转子动叶装配序列优化技术研究

针对航空发动机风扇转子奇数只叶片装配序列规划过程中存在的对顶角叶片重力矩差难以保证、叶片重力矩分布不够均衡的问题,研究了奇数只叶片的装配序列规划技术。首先,将单只叶片一分为二,形成33对“连体双胞胎叶片”,再转换成“66只虚拟叶片”,实现转子叶片数量“从奇变偶”的转换;然后,为每只“虚拟叶片”找到对顶角叶片,但是不能将“连体双胞胎叶片”真正分开或放在对顶角位置;最后,以对顶角位置上“两只虚拟叶片”的重力矩差为约束,以转子剩余不平衡量最小为优化目标,采用改进模拟退火算法规划动叶的装配序列,为转子装配提供优化的装配序列,优化转子的静平衡质量。实例验证表明,奇数只叶片数量“从奇变偶”转换,精确保证了对顶角叶片重力矩差,满足了设计部门给出的对顶角叶片重力矩差的设计指标(≤1200 g·mm),为奇数只叶片的转子动叶装配提供了优化的装配序列,并优化了转子的平衡质量。

一种新开发的ANCF缆索单元

为精确模拟系浮系统中系留缆索的动力学行为,应用绝对节点坐标公式(absolute nodal coordinate formulation,ANCF),开发一种新的ANCF缆索单元。该单元考虑了缆索的层级数目、各层材料的力学性能,并通过子域划分来更好地适应材料的层间差异。其中,利用Kelvin-Voigt模型来解释内芯层的黏弹性性质,而将改进后的Yeoh模型应用于护套层当中以更好地契合材料的超弹性性能。此外,设计一种具有隐式效果的差分格式对动力学微分方程组进行数值求解。最后,通过一系列静力学与动力学数值计算证明单元的精度与收敛特性,并对比几种应用不同超弹性模型的ANCF单元,证实应用改进的Yeoh模型的ANCF单元的合理性与优越性。

基于信号拟合和图像对比的有源配电网故障时刻检测方法

为了解决传统故障时刻检测方法较依赖采样频率且易受谐波和衰减振荡影响的问题,提出了一种信号拟合和图像对比相结合的故障时刻检测方法。首先,该方法将衰减因子引入傅里叶级数拟合模型,可精确拟合并扩展信号中的谐波和衰减振荡分量。然后,利用差异哈希对扩展信号和原始故障信号进行分段对比,使用中值滤波去除由拟合误差带来的零散像素点。最后,逐列检测故障时刻。仿真表明,该方法将检测误差控制在像素级,对采样频率较低或具有谐波和衰减振荡的信号也可准确地检测故障时刻,适用多种复杂的故障场景。

基于改进yolov5s网络的火焰检测算法研究

火灾因其破坏范围大,蔓延速度快等特点给人们的生命带来了威胁,使人们的财产遭到破坏,而准确的火灾检测在一定程度上能够避免灾难的发生,该文提出了一种基于改进yolov5s的目标检测模型。该模型在主干网络中加入CBAM注意力机制,使模型更加关注火焰信息,提高检测正确率;将主干网络中的C3模块改进为Ct2f模块,该模块通过ELAN的思想进行设计,让模型可以在保证轻量化的同时,通过更多的分支跨层链接获得更加丰富的梯度流信息;针对火灾视频检测,根据火焰燃烧时的动态特征,在该模型检测头部分加入帧间差分的思想,有效降低了对火灾视频检测的误判。实验结果表明,改进的yolov5s模型火焰检测平均精度更高,比yolov5s原模型平均精度提高了4.2%。通过火焰视频检测实验,表明该模型能够有效降低对火灾视频检测的误判。

不同模式下优质饲草生产经济效益分析

优质饲草是畜牧业高质量安全发展的重要保障。近年来,在粮改饲、高产优质苜蓿示范基地建设等项目带动下,宁夏饲草产业持续快速发展,对促进奶牛肉牛肉羊养殖业提质增效,带动农民增收发挥了重要作用。针对当前宁夏优质饲草生产仍存在缺口大、种植模式单一、适生优良品种缺乏等突出问题,2023年5月以来,自治区畜牧工作站优质饲草生产模式课题调研组,以平罗县为重点,通过实地走访平罗县9个乡镇的2家饲草生产企业、8家养殖场和5家种植户深入开展调研。调研以实地看、现场问、拉家常、深交流等形式,梳理分析饲草生产、供需现状、存在问题难题,研究提出了扩大宁夏优质饲草种植和提高土地利用效益的破解堵点、解决办法和应对卡点的具体措施。