西北地区农业生产的水成本评价及政策建议

缺水是制约西北发展关键因素,建设节水型社会必须特别重视农业生产的水成本问题,彻底改变大水漫灌的生产方式,走水商品水市场的道路。探索水成本市场化的科学路径,对西北地方政府的农业生产水战略和水政策进行重新设计,同时构建市场机制的国家技术支撑机制和政策体系。     

Multi-attribute evaluation of landscape-level fuel management to reduce wildfire risk

This paper provides an example of the practical application of multi-attribute trade-off analysis (MATA) to wildfire management. The MATA approach supports more informed decision-making because it exposes important trade-offs among competing management objectives (requiring value-based choices), helps guide and structure necessary technical judgements, explicitly represents uncertainty (i.e., not just expected outcomes but risk profiles around outcomes) and addresses temporal trade-offs. MATA promotes critical thinking about what analysis is required for decision-making. A MATA approach can be applied for all types of forest and fire management decisions. In this paper, we provide a sample application of MATA to an evaluation of landscape-level fuel treatments for managing wildfire risk. The study area is located in southeastern British Columbia, Canada where historical fire suppression policies and expanding development in wildland urban interface areas have resulted in an increase in both the probability and the consequences of stand replacement fires. We specify management objectives and develop measurable attributes for fire management costs, timber supply, property damage, landscape-level biodiversity, local air quality and climate change. We then simulate the effects on these attributes of four alternative fuel management strategies that include combinations of mechanical treatments and prescribed burning over a 100-year period. The evaluation illustrates the key features of MATA while highlighting the benefits and challenges of implementing the approach.     

设施葡萄智能化水肥管理体系研究

当前设施葡萄栽培中水肥盲目投入问题严重,因为缺乏灌溉决策标准导致农户实际生产中难以合理应用水肥一体化技术.利用基于NB-IoT网络传输的固态电阻传感器设备对设施葡萄根系土壤水分进行实时监测,建立了基于土壤水分张力的设施葡萄灌溉决策指标,并依托水肥一体化设备实现自动灌溉.研究结果表明:智能灌溉与施肥结合的综合管理比农户常...     

基于健康安全的棕地再开发决策模型构建及模拟研究——以广东省F市为例

为提高棕地再开发决策的科学性与安全性，以“建设用地准入机制”和“土壤环境质量标准”等为指导思想和标准依据，结合环境、经济、社会和地块特征等因素，构建棕地再开发决策指标体系及决策模型，运用模糊综合法对目标地块拟开发方向进行决策模拟。以广东省F市土壤环境质量调查和土地利用规划数据为基础，结合“三旧改造”规划方案，测算土壤污染程度，采用ArcGIS进行可视化安全评估，对目标地块再开发方向进行决策模拟，并以变动权重组合进行验证。结果表明： 37%的棕地再开发方向需要修正，在各影响因子中，环境因素权重最大，地块特征其次，社会和经济因素最小。研究表明，模拟决策模型确定的土地分级分类风险管控措施对棕地再开发决策具有较好的指导作用。     

水肥耦合对基质栽培番茄产量及品质的影响

为有效提高农业废弃物的利用率,将堆肥、秸秆等农业废弃物和黏土等拌制成一种抗旱促根的基质,研究水肥耦合效应对"爱吉3041"供试基质栽培番茄的株高、茎粗、产量、品质、水分利用效率(Water Use Efficiency,WUE)及肥料偏生产力(Partial Factor Productivity of Fertili...     

基于可拓评价方法的土地开发整理项目立项决策研究

项目立项决策是实施土地开发整理项目管理的重要内容,项目评价结果是立项决策的依据。该文在全国建立统一的项目评价指标体系的基础上,按区域和项目类型制定指标评分标准。并从初评合格的项目中抽取6个不同区域、不同类型的土地开发整理项目,运用可拓评价方法对其进行立项决策评价。     

基于Activiti和Drools的水产养殖自动决策流程管理系统

针对目前水产养殖过程管理中缺乏有效的流程化管理、养殖业务规则不明确、养殖决策效率低、人工经验判断操作失误率高等问题,阐述了工作流技术和规则引擎技术结合应用于水产养殖流程管理的设计思想。首先提出了一种基于规则引擎的智能工作流管理系统体系结构,并对系统进行总体框架设计。然后在分析和总结出水产养殖业务流程步骤繁琐不明确、受时间限制、多循环、多并发和存在大量养殖业务决策等特点的基础上,以南美白对虾养殖流程为例,通过Activiti可视化流程设计器对南美白对虾养殖流程进行流程定义和设计,构建水产养殖工作流模型;通过Drools规则引擎制定南美白对虾养殖关键流程业务规则库,制定过程包括养殖规则的分析、定义、设计、编写和触发。最后,将Activiti工作流引擎和Drools规则引擎与当今主流的SSH框架进行整合,开发基于Activiti和Drools的水产养殖自动决策流程管理系统。通过初期试验运行表明,该系统能有效实现水产养殖全流程业务状态的实时监控和养殖关键流程的规则决策,能有效增加养殖产量14.8%,降低饵料系数11.4%,减少人工管理成本30%,使得整体经济效益增加29.3%,初期试验效果良好,为水产养殖信息化过程管理提供了一种切实可行的流程化、自动化、精细化养殖的新策略。     

电动拖拉机底盘多目标优化设计

针对目前电动拖拉机底盘布置研究相对较少的情况,基于现有的整机匹配结果进行了底盘布置设计,利用三维建模软件建立模型,输入质量参数,提取整机主要零部件重心位置参数,然后通过分析拖拉机牵引机组作业时的力学特性,建立相关数学模型。以电动拖拉机的牵引效率和整机质量作为优化目标,采用NSGA-Ⅱ算法进行多目标优化。综合考虑了犁耕作业下拖拉机的稳定性要求、驱动力要求、载荷波动情况以及传动系和行走系零件寿命等影响因素,制定了算法运行的约束条件,建立了约束方程组。以电动拖拉机的使用重力、前后电池组的质心和整机质心为目标变量,推导出动力性和经济性最优的目标函数。通过ModeFRONTIER平台,采用NSGA-Ⅱ算法对电池分布式方案进行了多目标优化。两种不同耕深条件下的优化结果对比分析表明,按照本文方式优化布置后的电动拖拉机在耕深为180mm时,优化后的整体质量与经验法相比减少了14.3%,配重质量为25.3kg;耕深为240mm时,优化后的整体质量与经验法相比减少了10.3%,配重质量仅为4.4kg,说明在牵引工况下无需额外增加配重就能达到良好的牵引性能。与经验法相比,两种耕深条件下拖拉机的配重都小很多,说明基于传统拖拉机的配重经验法计算并不适用于电动拖拉机,同时也能说明,电动拖拉机因自身总质量超过同功率段传统拖拉机,可以通过合理设计底盘布置方案,在没有配重的情况下达到理想的牵引效率。优化后的电动拖拉机底盘布置方案,在作业工况下驱动轮滑转率小于特征滑转率,整机牵引效率明显提高。     

Uncertain and multi-objective programming models for crop planting structure optimization

Crop planting structure optimization is a significant way to increase agricultural economic benefits and improve agricultural water management. The complexities of fluctuating stream conditions, varying economic profits, and uncertainties and errors in estimated modeling parameters, as well as the complexities among economic, social, natural resources and environmental aspects, have led to the necessity of developing optimization models for crop planting structure which consider uncertainty and multi-objectives elements. In this study, three single-objective programming models under uncertainty for crop planting structure optimization were developed, including an interval linear programming model, an inexact fuzzy chance-constrained programming (IFCCP) model and an inexact fuzzy linear programming (IFLP) model. Each of the three models takes grayness into account. Moreover, the IFCCP model considers fuzzy uncertainty of parameters/variables and stochastic characteristics of constraints, while the IFLP model takes into account the fuzzy uncertainty of both constraints and objective functions. To satisfy the sustainable development of crop planting structure planning, a fuzzy-optimization-theory-based fuzzy linear multi-objective programming model was developed, which is capable of reflecting both uncertainties and multi-objective. In addition, a multi-objective fractional programming model for crop structure optimization was also developed to quantitatively express the multi-objective in one optimization model with the numerator representing maximum economic benefits and the denominator representing minimum crop planting area allocation. These models better reflect actual situations, considering the uncertainties and multi-objectives of crop planting structure optimization systems. The five models developed were then applied to a real case study in Minqin County, north-west China. The advantages, the applicable conditions and the solution methods of each model are expounded. Detailed analysis of results of each model and their comparisons demonstrate the feasibility and applicability of the models developed, therefore decision makers can choose the appropriate model when making decisions.     

月壤采样试验验证机构运动性能研究

为开展月壤采样试验,设计了一种可以实现姿态调整的3自由度并联机构,根据机构运动特点,采用修正的KG(Kutzbach-Grübler)公式计算机构的自由度,利用封闭矢量法求解该机构位置逆解,并建立机构速度、加速度和可操作度性能评价指标。提出一种基于速度性能与可操作度性能为目标,采用多目标遗传算法优化机构结构参数,对优化后的结构参数进行分析,得到该机构工作空间、速度性能、奇异性和可操作度性能。研究表明:动平台姿态α、β在-0.35~0.35 rad时,机构速度性能最好;可操作度性能指标均在[4,5]区间范围内,不会产生奇异位形,有较好的可操作性能,验证该机构能够满足月壤采样试验功能要求,对开展月壤采样试验验证具有一定的实用价值。