基于区间两阶段模糊可信性约束模型的灌区水资源配置

针对灌区水资源配置系统中的复杂性和不确定性,以湖北省漳河灌区为例,构建区间两阶段模糊可信性约束规划模型,实现灌区各用水户间水资源优化配置。模型以系统经济收益最大为目标函数,引入模糊变量、离散区间和概率分布表征系统中的多重不确定性,设置可信性置信水平解决带有违规概率的模糊风险问题。求解模型得到多种情景下水量、灌溉面积优化配置结果以及系统收益,结果表明,模型可以有效处理配置系统的不确定性问题,反映系统收益与风险之间的权衡,实现灌区水资源高效配置。优化结果有助于灌区管理者协调各用水户的利益冲突,制定合理的决策方案。     

不确定条件下的区间两阶段模糊可信性约束规划配水模型研究

以黑河中游为研究对象,考虑农业灌溉系统的不确定性,建立了区间两阶段模糊可信性约束规划模型,用于区域农业水资源优化配置。该模型以经济效益最大为目标函数,引入模糊变量、概率分布和区间数来表示多重不确定性。通过设置不同的可信性置信水平,模型可解决带有违背约束的模糊风险问题。模型的结果可为黑河中游地区农业水资源优化管理和作物种植结构优化提供帮助。     

基于WEAP模型的龙口市水资源优化配置研究

以龙口市为例,利用WEAP(Water Evaluation And Planning,水资源评估和规划系统)软件建立了水资源优化配置模型.该模型把满意度函数作为水资源优化配置模型的目标函数,满意度函数包括3个子函数,即:社会效益、经济效益和环境效益.在不同的节水和经济发展速度下的5个方案进行了模拟计算,求得社会效益,...     

基于评价的水资源优化模型适用性比较

为了比较不同目标的水资源优化配置模型在黑河中游的适用性,在充分考虑地表径流随机性的基础上,分别构建以灌区农业水生产力最大、农业灌溉损失最小、净经济效益最大为目标函数的灌区水资源优化配置模型,并引入多指标综合评价法以及熵权法对3个优化模型的配置结果进行综合效应评价．评价结果显示,基于黑河中游水资源利用现状,以灌区农业水生产力最大为目标函数的模型,更适合现阶段黑河中游灌区水资源配置要求．使用灌溉水生产力最大为目标函数的优化模型对有限水资源进行优化后的配水方案整体用水比现状水平年减少了334×108 m3,灌溉水生产力增加了0453 kg／m3,用水成本比实际减少了421×107元．评价结果验证了水资源优化配置模型方案评价的可行性．     

基于改进飞蛾扑火算法的区域水资源优化配置模型研究

为解决复杂的区域水资源优化配置问题,以区域缺水率最小和污染物排放量最小为目标函数建立了水资源优化配置模型,并以汾河下游谷地供水区为例,预测其在规划水平年20%、50%、75%和95%来水频率下的供需水量。针对飞蛾扑火算法(MFO)存在的搜索耗时较长、易陷入局部最优的问题,改进其烛火更新公式及对数螺旋函数。通过对群智能算法中常用的测试函数做仿真实验,对比分析了改进前后MFO算法的寻优结果,并采用改进的MFO算法对模型进行求解。实例结果表明,所构建的区域水资源优化配置模型合理有效,改进的飞蛾扑火算法收敛速度快,寻优性能优越,可用于水资源优化配置领域。     

面向生态的黑河中游模糊多目标水资源优化配置模型

以黑河中游为例,构建面向生态的单目标(模型一)和多目标(模型二)水资源优化配置模型,并进行对比分析。其中,单目标模型的目标函数是农业和生态产生的经济价值最大;多目标模型的生态目标是生态供水满意度最大,经济目标是农业产值最大。为了保证生态用水,模型中引入0-1整数规划来优化传统灌溉和节水灌溉的种植面积,同时,考虑到模型参数的不确定性,将模糊数引入到已建模型中。分别对2个模型求解,得到从不同角度出发的各个计算单元的水资源优化配置结果,为当地的生态保护提供了有力的决策支持。     

跨流域调水工程支线调蓄水库对沿线受水区水资源配置的影响分析

分析了有支线调蓄水库的跨流域调水工程水资源系统的结构和特点,定性分析了支线调蓄水库对跨流域调水工程沿线受水区水资源配置的影响。将数学规划与模拟技术结合,建立了由受水区水资源优化配置和干线调水协调模拟模型组成的跨流域调水工程水资源优化配置模型。采用大系统分解协调原理进行模型求解,通过有无支线水库水资源配置效果的对比分析,量化了支线调蓄水库对受水区水资源配置的影响。以南水北调中线工程河南段为例进行了应用研究,结果表明,模型和方法合理可行。     

交互式两阶段分位值水资源系统规划模型

开发了一种交互式两阶段分位值优化(ITFO)模型,并将其应用于不确定条件下水资源系统规划问题。该模型将分位值优化方法引入随机规划模型中,用于处理目标函数和约束两侧的双重不确定性,同时体现决策者对水资源系统收益的偏好。结果表明:1ITFO模型可以有效解决水资源系统规划问题,得到不同可信度和分位值下系统收益和水资源分配量;2可信度θ与系统收益上界呈现反比关系,与系统收益下界呈现正比关系,即随着可信度θ的增大,系统收益值减小,同时系统收益区间变小,不确定性降低。3分位值pne与系统收益呈现反比关系。ITFO模型可以为决策者提供可行的水资源系统方案,使水资源系统分析更加符合客观实际。     

基于改进型NSGA-Ⅱ算法的晋中市水资源优化配置

对水资源的不合理利用而导致的水资源短缺现象愈发频繁，进行水资源优化配置的需求也越来越大。水资源优化配置是指在水资源总量有限的前提下，综合考虑社会效益和经济效益，用科学有效的方法对水资源进行水量的合理分配。首先分析晋中市的水资源状况，综合考虑晋中市水资源优化配置需求，建立了以社会效益和经济效益为目标函数的晋中市水资源优化配置模型。接着提出了一种改进型NSGA-Ⅱ算法（INSGA-Ⅱ），并用INSGA-Ⅱ算法对ZTD1、ZTD2及ZTD3等6个多目标测试函数进行实验，结果表明提出的INSGA-Ⅱ算法能求得有效的帕累托前沿，同时收敛性和分布性均优于所列举的大部分多目标优化算法。最后将INSGA-Ⅱ算法应用于晋中市水资源优化配置模型中并进行实例分析，同时与基于NSGA-Ⅱ算法的方案进行对比。实例分析结果表明，基于INSGA-Ⅱ算法的水资源优化配置方案比基于NSGA-Ⅱ算法的水资源优化配置方案得到的缺水量更小、经济效益更高，证明了基于改进型NSGA-Ⅱ算法的晋中市水资源优化配置方案的可行性。根据决策者对不同目标的偏好不同，给出了3种优化配置方案和3种方案的效益比较，这些配置方案同时考虑了社会效益...     

玛纳斯河流域水资源优化配置研究

以玛纳斯河(玛河)流域为研究对象,基于玛河流域可持续发展的思路及流域水资源系统特征,引入多目标水资源配置模型,并采用基于欧氏距离的交互式模型求解方法,计算了各水平年规划年的水资源优化配置结果,并根据目标满意度及目标总体协调度对配置结果进行了评价。计算结果可为玛纳斯河流域水资源配置提供决策参考,以提高流域的水资源利用率。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。