基于NGO-CNN-SVM的高标准农田灌溉工程施工成本预测

为提高高标准农田项目施工成本的预测精度,控制施工成本在合理范围,减少投资风险,该研究从单体灌溉工程施工成本预测角度出发,通过随机森林（random forest,RF）筛选出高标准农田灌溉工程施工成本的关键影响因素,结合卷积神经网络（convolutional neural networks,CNN）和支持向量机（support vector machine,SVM）两种模型的优点,通过北方苍鹰优化算法（northern goshawk optimization,NGO）对模型里的惩罚因子和核参数进行寻优,构建基于NGO-CNN-SVM的施工成本预测模型。通过辽宁省2018—2023年高标准农田工程中灌溉工程的施工成本数据,选取样本决定系数R²、平均绝对误差MAE、平均绝对百分比误差MAPE和均方根误差RMSE作为精度指标进行分析,结果表明：基于NGO-CNN-SVM的施工成本预测模型在渠道工程中MAE低于0.615万元,RMSE低于0.512万元,R²达到0.968以上,相对误差小于4.210%;在进水闸工程中MAE低于0.610万元,RMSE低于0.536万元,R²达到0.966以上,相对误差小于4.410%;在桥涵工程中MAE低于0.494万元,RMSE低于0.477万元,R²达到0.970以上,相对误差小于3.548%,并相比较于反向传播神经网络,CNN和CNN-SVM模型,NGO-CNN-SVM模型的预测结果均最优。通过特征选择、模型融合、算法优化以及不同模型对比表明NGO-CNN-SVM模型具有更高的预测准确率和泛化性,可为高标准农田灌溉工程施工成本预测提供理论依据。     

浅谈工程造价的预结算审核

工程造价的预结算审核是合理确定工程造价的必要程序及重要手段.本文从工程造价中存在的问题,工程造价审核的内容、方法等三个方面论述了工程造价及其预结算的审核工作过程.     

成本核算是施工项目成本管理的核心

论述了成本核算的意义及重要性,阐明成本核算是施工项目成本管理的核心,应加以重视。     

Cost analysis of sand barriers in desertified regions based on the land grid division model

Sand barriers are the most widely used mechanical implements for wind-blown sand control and desertification prevention. However, there is no standard quantitative cost analysis of the sizes and materials required for sand barriers. In this study, based on the original land grid division model for optimal resource utilization, we calculated the total side lengths of square and regular hexagonal sand barriers with the sizes of 1.0 m×1.0 m, 2.0 m×2.0 m, and 3.0 m×3.0 m in a desertified region of t...     

无粮饲料原料的开发利用

无粮饲料是以农作物废弃物、优质可再生牧草等为原料,通过人工处理,制作成适合投喂的畜禽饲料。无粮饲料的开发与应用,既可节约养殖成本,又可为人们提供优质的畜禽产品,其发展前景广阔。对无粮饲料原料的开发利用进行了综述。     

TRANSFORMATION OF AGRICULTURE ON THE LOESS PLATEAU OF CHINA TOWARD GREEN DEVELOPMENT

● Agriculture on Loess Plateau has transformed from food shortage to green development. ● Terracing and check-dams are the key engineering measures to increase crop yields. ● Agronomic measures and policy support greatly increased crop production. ● Increasing non-agricultural income is a key part of increasing farmers’ income. ● Grain for Green Program had an overwhelming advantage in protecting environment. Loess Plateau of China is a typical dryland agricultural area. Agriculture there has transformed from food shortage toward green development over the past seven decades, and has achieved world-renowned achievements. During 1950–1980, the population increased from 42 to 77 million, increasing grain production to meet food demand of rapid population growth was the greatest challenge. Engineering measures such as terracing and check-dam were the crucial strategies to increase crop production. From 1981 to 2000, most of agronomic measures played a key role in increasing crops yield, and a series of policy support has benefited millions of smallholders. As expected, these measures and policies greatly increased crop production and basically achieved food security; but, low per capita GDP (only about 620 USD in 2000) was still a big challenge. During 2001–2015, the increase in agricultural and non-agricultural income together supported the increase in farmer income to 5781 USD·yr^–1. Intensive agriculture that relies heavily on chemicals increased crop productivity by 56%. Steadfast policy support such as “Grain for Green Program” had an overwhelming advantage in protecting the natural ecological environment. In the new era, the integration of science and technology innovations, policy support and positive societal factors will be the golden key to further improve food production, protect environment, and increase smallholder income.     

农村建设中太阳能路灯综合效益评价研究

我国新农村建设中太阳能利用取得了快速发展,本文简要介绍了太阳能路灯系统的工作原理,结合某市循环经济示范村太阳能路灯系统的使用现状,采用费用-效益评价指标从经济、环境和社会效益3个方面对太阳能路灯系统进行综合评价与分析,得到太阳能路灯与普通路灯相比较,在经济上是可行的;安装太阳能路灯系统减少了对环境的污染,提高了可再生能源的利用价值,对于该旅游区的环境保护具有重大意义;对新农村建设新能源的利用,起到了很好的引导作用,为太阳能路灯系统大力推广提供一定的实践依据。     

Analysis of Measurement Items Composition under Bills Pricing Mode

This paper analyzes contractor's pricing connotation during bidding period with the implementation of National Standard GB50500-2003 and publish of document JB \206,expatiates the contents of measurements during construction period.Considering the problems derived from expenses of measurements during accounts settlement stage,a classified management method according to the characteristics of these measurements is put forward,and one step further,the rational pricing method of measurement items during the bidding period is suggested.     

A Spot Price Model with Var Cost

This paper has applied the var cost to the theory of spot price.An augmented Lagrange method is employed to develop the exact model of spot price of active power and reactive power,and the physical means of Lagrange multipliers are explained.The numerical examples are given to demonstrate the validity of the proposed model.     

Analysis of Project Audit''s Function and Civil Action

Audit takes a unique status and has obvious function in financial surveillance system.The Audit is used to superintend the factuality,validity and virtue of fiscal and financial income and expenses.In the renewed China Audit law the functions and status of official audit have been intensified,and the qualification and status of Audit department as executing office is confirmed.This paper analyzed the official construction project audit's function and legal status.