Reservoir operation management through optimization and deficit irrigation

One of the methods for increasing productivity of water consumed in agriculture is by improved water supply management. This paper presents results from an optimization study of the Malampuzha irrigation project of the Bharathapuzha river basin of Kerala in India. The objective of this study is to determine whether significant improvements might be realized from optimization of operation of the reservoir system. To do this a mixed integer linear programming (MILP) model is developed and five different management strategies are tested. The result indicates that a management strategy with deficit irrigation by supplying less water in non-critical growth period and maximum water during stress sensitive periods is a best viable solution for better performance. A MILP model, rather than a linear programming (LP) model, is used to ensure that the reservoir does not spill before reaching its capacity.     

基于参数化白车身下车体结构轻量化研究

在过往开发流程中,车身概念设计阶段,白车身性能得不到充分验证,若在概念设计阶段结合SFE进行车身优化,以仿真驱动设计,在白车身概念设计阶段就介入到车身性能评估,让车身在详细设计前就拥有比较好的弯扭刚度等性能。基于此,采用SFE-Concept建立了白车身概念设计阶段全参数化模型,通过筛选下车体结构更改地板下横梁,设计变量包含横梁厚度、横梁位置以及横梁截面形状3个维度,根据3个维度的变量进行试验设计(DOE),然后实现响应面近似模型的自动生成和验证。最终,采用序列二次规划法(SQP)进行优化,得到妥协解集,最终比较不同的解集,选取白车身质量最小的解作为优化解,优化后白车身下车体质量减轻3.64 kg。     

Performance based irrigation planning under water shortage

A linear programming (LP) based optimization model and a simulation model are developed and applied in a typical diversion type irrigation system for land and water allocation during the dry season. Optimum cropping patterns for different management strategies are obtained by the LP model for different irrigation efficiencies and water availability scenarios. The simulation model yields the risk-related irrigation system performance measures (i.e. reliability, resiliency and vulnerability) for the management policies defined by the optimization model. The alternative strategies are evaluated in terms of all performance criteria (i.e. net economic benefit, equity and reliability) simultaneously through a trade-off analysis using a multi-criteria decision making method (compromise programming). For the case study of the Kankai irrigation system in Nepal, with equal preference to the objectives, a management strategy with equal share of water among the project subareas appears to be the most satisfactory alternative under water shortage conditions. The existing water allocation policy is not economically efficient. Deficit irrigation in Early paddy appears attractive under favorable hydrologic scenario, particularly if accompanied by measures to improve existing irrigation system efficiency.     

小型水电厂优化运行求解方法的对比研究

针对小型水电站的实际情况和运行特点，建立了小型水电厂优化运行问题的数学模型，并提出了用递推优选法进行求解的具体思路。通过对动态规划和递推优选两类求解方法的对比分析，表明用递推优选法求解小型水电厂优化运行问题，既可避免由于曲线转换和拟合带来的误差，又简单实用。     

基于NSGA-Ⅲ算法与TOPSIS决策下的区域水资源多目标优化配置

为缓解水资源供需紧张,指导区域用水管理,以社会、经济、生态综合发展为目标,供水量与需水量双向约束构建区域水资源优化配置模型.结合该模型特点,引入NSGA-Ⅲ算法对模型进行求解,以寻求Pareto前沿面与最优解集.同时,利用TOPSIS决策理论对众多Pareto可行解进行综合评价,选择权衡解作为最佳折衷方案.将该模型应用于南阳市鸭河口灌区进行验证,对灌区来水频率P=75%时下近期水平年与远期水平年进行水资源优化配置,并进行二次水资源供需平衡分析.结果表明,相对于基本方案,折衷方案在近期水平年余水量增长至11 497.60万m3,可节约水资源3 272.38万m3;远期水平年由缺水4 279.28万m3变为余水3 950.30万m3,可节约水资源8 229.58万m3,节水效果明显,符合鸭河口灌区整体规划与用水需求.     

基于近红外光谱技术的蔬菜农药残留种类检测

该文基于近红外光谱技术,提出一种快速无损检测方法,以期实现蔬菜农药残留的分类检测。通过对喷洒了氰戊菊酯溶液、三唑磷溶液和未喷洒农药的生菜样本进行研究,比较不同预处理后的建模效果,选用SNV算法作为最优预处理方法。分别采用连续投影算法（SPA）、自主软收缩法（BOSS）和竞争性自适应重加权算法（CARS）对预处理后的光谱数据进行特征波段选择。采用支持向量机（SVM）和基于灰狼算法（GWO）优化的支持向量机（SVM）算法对特征波长变量分别建立分类模型。再通过对建立的模型进行比较得出:CARS-GWO-SVM模型取得了最佳的分类效果,模型的训练集精度和预测集精度均为100%。因此,利用近红外光谱技术对蔬菜上的农药残留进行分类检测是可行的。该研究为生菜中其他农药残留的快速无损检测分析提供参考。      

基于双层分式规划的种植结构多目标模型研究

构建了基于双层分式规划的种植结构多目标优化模型,并通过交互式模糊规划方法进行求解。该模型可以定量得到研究区域在最小灌溉水量情况下的最大种植收益,避免多目标模型求解过程中的主观性;可以兼顾并综合上层管理者和下层管理者的种植方案决策。将构建的模型及相应求解方法应用于黑河中游甘州区、临泽县、高台县的种植结构优化中,并将优化结果与实际结果进行对比,结果发现:优化的种植结构整体效益增加3.2×108元,整体用水量减少1.3×109m3,单方水种植效益比实际增加了1.94元/m3,得到的结果验证了模型及求解方法的可行性。构建的模型与得到的优化结果可为黑河中游及类似地区作物种植结构优化提供理论依据与决策支持。     

自压式树状管网的两级优化设计模型与神经优化设计

建立了自压式树状管网两级优化设计模型，并用人工神经网络法实现树状管网非线性规划模型的快速求解。采用的人工神经网络技术的两级优化设计模型在适用范围、求解速度和获得最优解能力上，均优于单一的非线性规划模型和线性规划模型，是实现树状管网全局优化设计的一条新途径。     

考虑不同层次利益主体的灌溉水资源优化配置

针对灌溉水资源优化配置中存在的非线性和不确定性等特点,同时考虑灌区不同层次决策主体利益,分别构建考虑上层管理者利益的区间线性分式规划(ILFP)模型以获得最大的灌溉水生产力和考虑下层农民利益的区间二次规划(IQP)模型以获得最大的产量。在此基础上,将灌区上、下层利益主体作为整体,构建线性分式二次双层规划(LFQBP)模型,以协调灌区不同层次决策主体利益,促进灌区可持续发展。将所构建模型应用于盈科灌区的粮食作物配水中。通过配水结果的比较来分析各模型的性质,结果表明ILFP模型和LFQBP模型更适用于干旱地区。所构建模型从不同角度反映灌溉配水的实际问题,其优化结果有助于灌区管理者权衡各层决策主体间的利益。     

Modelling the economics of animal health control programs using dynamic programming

A new application of an optimization tool, dynamic programming (DP), is described to model the economics of animal health control programs. To demonstrate the value of this technique, a model is applied to determine optimal net benefits of controlling East Coast fever (ECF) in Malawi Zebu cattle in the Lilongwe plateau. The objective function was the present value of net benefits due to treatment, defined as mortality savings minus treatment costs. Mortality savings were based on decreased mortality from ECF following treatment. Model constraints included herd size, animal (herd) nutritional requirements, and program budget. Treatment options were tank dipping in acaricide, and vaccination. Secondary data from a dipping trial of 1800 Malawi Zebu cattle conducted from 1991 to 1994 were used to determine probabilities of mortality. Total optimal net benefits of long-term treatment (25 years, i = 10%) from vaccination (Malawi Kwacha (MK) 21 069) exceeded benefits for treatment with chlorfenvinphos acaricide (MK15 203).     

基于蚁群算法的泵站运行优化及投影寻踪选优策略

针对泵站优化运行计算时最优解评价指标单一的问题,建立了包含机组开停机约束的泵站优化运行数学模型和运行方案选优的投影寻踪决策模型.提出了求解泵站多机组优化运行模型的蚁群算法,并通过分析模型的特性改进了算法中启发式信息和信息素更新方式.对江都四站多机组日优化运行计算的结果显示,变量同等离散的情况下,利用蚁群算法优化的结果比用动态规划逐次逼近法优化的结果节省了2.8％的电费,前者相比设计工况运行时节省了29.2％的电费,且蚁群算法优化结果对应的运行方案中叶片调节次数少,机组运行时间短;方案选优时投影寻踪决策模型能够兼顾多个评价指标的优选,得到的运行方案不仅运行成本低,且更合理,更贴切于日常运行,可见改进后的蚁群算法结合投影寻踪决策模型在泵站优化运行及相近的领域有较大的实用价值.     

Assessing multi-criteria approaches with environmental, economic and social attributes, weights and procedures: A case study in the Pampas, Argentina

Soil erosion control is a major issue in agriculture. The no till system of soybean production has been widely adopted; however, soil erosion may increase due to pasture and forestry land convertion to cropland in the marginal Pampas, Argentina. The aim of this paper is to assess the conflicts and trade-off among environmental, economic and social interests by using three continuous multi-criteria approaches and a set of different weights. Different land uses, crops, pastures, forestry and soil and water conservation practices at the basin scale in the marginal Pampas were assessed. The basin (423 km²) was discretised into 176 sub-basins to focus the management strategy on 5th and 6th order streams. Minimum basic information was obtained using intensive field observations and satellite images. The basin hydrology, soil erosion, sediment delivery and vegetated filter strip models and GIS were used to quantify the technical coefficients. Thirteen decision factors and six criteria (peak run-off, annual erosion, sediment, investment, gross margin and employment) were used in the optimisation trials. Weighted goal programming, lexicographic goal programming, compromise programming and a sensitivity analysis of weights were performed. The results showed a high impact of soil and water management practices on the environmental factors and a strong conflict between environmental and economic interests. The three multi-criteria approaches also showed that it is possible to obtain a good level of goal achievement with different plans. These plans should include: soil conservation practices; crop rotation (of a 2:1 soybean-to-corn ratio); gully and channel erosion control; regulation ponds; and pasture and agro-forestry areas. This goal achievement is mainly limited by public and private investment. Sensitivity analysis of the decision-maker weights shows differences among the values achieved by the criteria and their trade-off. Thus, the weight value of each criterium should be supported by the negotiation-consensus process.     

基于结构模块化方法的小麦联合收获机方案设计

根据结构模块化设计方法的特点，对小麦联合收获机的方案设计过程进行了研究，将层次分析法和动态规划结合起来，提出了动态规划寻优评价模型，并在此基础上开发出小麦联合收获机方案设计的软件系统。实践表明，动态规划寻优评价模型合理，寻优速度快。     

民勤县主要作物优化灌溉制度制定及风险分析

根据由气象站和田间试验搜集到的民勤县各灌区1985—2008年间统计数据资料,建立了民勤县典型作物基于机会约束规划的优化灌溉制度模型,利用动态规划方法求解,制定出了几种典型作物在不同水文年的灌溉制度,其节水增产效果显著,并对其用水风险进行了分析。     

基于模态分析的机械式无级变速器星形轮的优化设计

机械式无级变速器在机械传动调速方面发挥着巨大的作用。建立以总传动比最大为目标函数的优化模型,利用MATLAB编程求解,得到优化后的结构尺寸。分别以优化前后的结构尺寸在PRO/E中绘制凸轮式无级变速装置三维实体模型,对输出轴进行力学分析,对传动齿轮进行模态分析,对比总变形量。结果表明,该设计有利于降低结构尺寸,减少制造成本。     

基于SQP算法的形状误差统一评定

根据形状误差定义及数学规划理论,建立了形状误差包容评定的统一的非线性规划模型,指出了这模型实质上是多目标优化的问题。再将该优化问题转化成单目标优化问题,并对该问题提出了用逐次二次规划的解法（SQP法）。由于模型是凸的,在求解中SQP法又能保留非线性的信息,因此评定过程对初始参数的要求低,且稳定、可靠、效率高。几个算例的验证结果均符合凸规划全局最优判别准则。     

Modelling multiple objectives of land use for sustainable development

Sustainability is a human-centred concept that comprises multiple aspects and objectives of different interest groups. Sustainable development is not readily measurable, except as a compromise between different parts of society, of which some may try to represent future generations of mankind. To determine a sustainable development path in the relationship between agriculture and its natural environment, a profound knowledge of this complex system and its behaviour under different socio-economic conditions is necessary. We present a modelling system which consists of a set of hierarchically linked modules. These modules describe production activities in a way that allows an economic and ecological analysis of these techniques. The heart of the modelling system is a multiple goal linear programming model, which is generated by data base modules. Simulation of single farm models as well as regional models based on simultaneously optimised farm types is possible. The modelling system appears to be a highly flexible tool with respect to the number and type of farms, sites and production techniques. Environmental objectives can easily be included and different levels of goal achievement can be simulated. It is well suited for single farm analysis as well as for regional models, for static as well as dynamic approaches. It allows rapid adoption of the model and rapid calculation of scenarios. Therefore, it is suited for use in interactive environments with users which are interested in repeated runs with little changes in the goal function, prices, subsidies or technical coefficients. The results can be used for policy decisions as well as the strategic planning of individual farmers. Applications of the modelling system will be presented in following papers. In this paper the kind of information the model can generate and the circumstances of their usage are shown. ©     

水平对置二冲程活塞发动机工作特性仿真研究

利用Comsol软件对水平对置二冲程活塞发动机工作特性进行仿真。首先,确定发动机的曲柄连杆机构的运动形式以及各部分的受力情况;再通过设定7组不同摇臂数据对置活塞发动机的曲柄连杆机构,同时,确定曲柄连杆机构的其它部分数据;然后,利用Comsol软件建立水平对置二冲程活塞发动机仿真模型并对构件运动进行仿真分析,得到曲轴转角与活塞位移的相关数据并导入到GT-power模型中。利用GT-power软件仿真依次得到各组方案的P-V图及缸压图,从而得到各方案的最大压力与功率并进行参数化分析,最终得到最佳方案。     

基于线性规划的给水管网系统动态有限元优化设计

给水管网系统优化设计是解决城市供水管道故障有效方法之一,通过将给水管网年折算费目标函数对管径的非线性函数作线性处理,从而建立了每一段管网的造价折算模型,并以表征给水管网特征的坐标参数作为约束条件,计算出线性规划最优解,且对管段能量方程作线性处理,在水力学动态平衡原理和有限元理论基础上,建立有限元分析模型.该计算模型实用简便,可为工程应用提供参考.     

Border fertigation: field experiments and a simple model

Fertilizers are commonly dissolved in border irrigation water. However, there are no available procedures for the proper design and management of surface fertigation. A series of experiments was conducted to determine the uniformity of fertilizer application under varying inflow discharges and fertilizer application times in blocked-end borders. Results from the fertigation evaluations showed that the fertilizer distribution uniformity of the low half (DULH) ranged from 2.9 to 51.6%, while water DULH ranged from 63.5 to 96.9%. A simplified border fertigation model based on one-dimensional convection was formulated and applied to the simulation of the experiments. The model was able to explain 43.8% of the variability in the fertilizer DULH. Application of the model to selected case studies revealed that short-duration applications, such as those resulting from instantaneous release of fertilizer into the irrigation stream, often produce low uniformities. This is particularly true for early applications in blocked-end borders and for early and late applications in level basins. In both irrigation systems, application of fertilizer at a constant rate during the entire irrigation event is frequently the best solution. In the presence of runoff, the model can be used to find a compromise between fertilizer application uniformity and runoff losses. Finally, if large deep percolation losses are expected, the model can identify uniform fertigation options based on late applications of fertilizer. Received: 8 August 1996