Ongoing performance assessment — a case study of Kraseio Project,Thailand

The introduction of computer assisted irrigation scheduling to a 20,000 ha smallholder rice and sugarcane irrigation project in Thailand has provided an opportunity for continuous performance assessment. The provision of weekly information on performance is exerting an influence on the management of the system thus enabling timely response to operational problems.Kraseio Project has been operating with an improved water management system for two seasons, incorporating simple performance indicators, namely: actual versus targetted supply, along with equity, reliability and adequacy measures. Over these seasons the value of regular feedback of performance information has been demonstrated, in terms of increased awareness by project staff of operating constraints and their ability to quantify project performance.     

中国科学院栾城农业生态系统试验站农田节水研究过去、现在和未来

本文回顾了中国科学院栾城农业生态系统试验站(以下简称栾城试验站)建站初期20 世纪80 年代以来在农田节水方面开展的研究。20 世纪80 年代以作物优化灌溉制度为研究重点, 解决生产实际问题; 20 世纪90 年代围绕土壤-植物-大气系统水分传输和界面调控开展了系统研究, 为农田节水措施的形成提供理论基础和技术途径; 近10 年来进一步深化了农田节水生理生态研究, 并根据多年研究积累, 形成了综合节水技术模式, 进行推广应用。未来栾城试验站农田节水工作将更加突出多学科渗透交叉, 以提高农田水分利用效率和效益为目标, 加强基础研究和节水技术的示范应用。     

Simulation method for multi-machine and multi-task crane scheduling in steelmaking plant

It is of great significance in steel complex to link production flow between work stations and control production rhythm by cranes. Crane scheduling is a multi-machine multi-task problem which limits temporal and spatial constraints and production plan. A simulation model based on evolution rules to solve temporal and spatial constraints is proposed. Its objective is to guarantee execution of production plan in steelmaking plant. And match between cranes and production task on working span is conducted to fulfill temporal constraints between multi-tasks and spatial constraints among multi-cranes. Simulation rules including task allocation, conflicts eliminating and task finishing are also proposed to dominate simulation process. This model avoids difficulties of theoretical calculation for crane scheduling problem. Offline test in a steelmaking plant shows that it is available to make a crane scheduling without conflicts between cranes and plans, which provides a guideline for production scheduling.     

混合动力汽车CAN网络优先级动态分配方法

在混合动力汽车网络结构和消息实时性分析的基础上,将最早截止期优先算法(EDF)引入到网络集成协议设计中,提出基于EDF调度的优先级分配策略,给出了实现该策略的非均匀分区编码方法及可调度判定条件,指出了该判定条件下的分区因子无关性.仿真结果表明该方法能够满足截止期变化范围较大的CAN消息集传输要求,使网络具有较高的利用率.     

塔克拉玛干沙漠南缘不同植被区土壤水分状况研究

在新疆干旱气候条件下,2009年通过对棉花膜下滴灌进行试验研究,分析了不同灌溉定额和灌水周期对土壤水盐分布及棉花生长的影响。结果表明,灌水周期5d的处理能够达到棉花最适宜的土壤水分范围。在相同的灌水周期下,土壤剖面平均含水量随着灌溉定额的增加而增大。较高灌水频率对根区土壤盐分具有较好的淋洗作用,灌水周期10d的处理,土壤盐分波动变化较大,在生育期内土壤盐分出现累积现象。从节水增产和抑盐方面考虑,灌溉定额3 900m3/hm2,灌水周期为5～7d的灌溉制度适合北疆农业生产。     

电站运行对流量时间序列影响评价方法初探

大坝建设会对河流水文情势带来影响,进而影响河流生态系统.针对水电站调度对河流水文情势影响评价问题,引入分形理论,采用分形维数来评价电站调度对水文情势的影响程度,并将其用于东江上游枫树坝电站调度对其下游水文情势影响评价.采用龙川水文站49 a日流量数据进行计算,并与变差系数、峰度值进行对比分析,结果表明,分形维数与变差系数、峰度值对流量过程变化表征一致.分形维数明确表征洪水的集散程度和变化频率,即洪水集中,变化频率低,分维数相对较小;反之,分维数相对较大.同时,分形维数可以用来评价年度水文过程的自相似性.     

混沌粒子群微分进化算法及其在水库发电优化调度中的应用

粒子群优化算法（PSO）与微分进化算法（DE）都是有效的基于群体智能的全局优化算法,但它们都容易过早收敛,陷入局部最优。针对以上问题,提出了混沌粒子群微分进化算法（CPSO—DE）,该算法引入可变的惯性权重和学习因子,以基于logical映射的混沌序列代替标准PSO中的随机序列来对粒子群进行初始化,同时将微分进化算法（DE）中的变异、交叉和选择思想引入标准PSO算法中,改变标准PSO算法单一的进化策略,在全局范围内搜索最优解。作为实证的需要,通过对水库优化调度所存在问题的分析,建立了基于CPSO-DE算法的水库优化调度数学模型与求解算法,并以某水库实际运行数据进行计算,结果表明CPSO-DE算法具有较好的全局最优解,验证了CPSO—DE算法的可行性与健壮性。     

节水型园林植物优化灌溉制度的制定

灌水安排的理想情况是当实际的土壤水分消耗量达到预定的允许耗水量时进行适时灌溉,灌溉水量应当是将土壤湿度水平返补至预期的水平(通常为田间持水量)时需要的水量.该研究给出了基于土壤类型、管理允许耗水量以及田间观测方法确定允许耗水量的计算依据.介绍了基于历史月度参考腾发量ET数据、当前(日)参考腾发量ET数据,或者应用土壤水分平衡方法、土壤湿度或土壤张力传感器来确定绿地植物灌水周期的方法.给出了基于历史月度参考腾发量ET数据、当前(日)参考腾发量ET数据及湿度传感器来确定灌水周期植物净需水量和灌水周期基础灌溉需水量的计算过程.为避免地面径流,可通过观察的方法或者通过基本渗吸速率法确定小循环的数量,并确定小循环之间的浸透时间.管理者应该对园林绿化进行定期观测,并对灌水安排做出必要的调整.     

Water use of young ‘Fuji’ apple trees at three soil moisture regimes in drainage lysimeters

Studies were conducted during 4 months of each growing season in 1994 and 1995 to measure water use of young apple trees (Malus domestica Borkh. cv ‘Fuji’) growing under different soil moisture regimes in temperate climate conditions and to evaluate monthly crop coefficients of such conditions. To do so, double pot lysimeters under a transparent rain shield were designed and installed. The three soil moisture regimes in three replicates each were: (A) drip-irrigation at −50 kPa of soil matric potential (IR50); (B) drip-irrigation at −80 kPa of soil matric potential (IR80); and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, soil surface was maintained with or without turf grasses. Monthly water use was not different in drip-irrigated treatments (IR50 and IR80), but greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees (r² values of 0.76^*** for IR50 and of 0.77^*** for IR80), while those obtained in the WT45 treatment fluctuated. Leaf water potential (LWP) of drip-irrigated trees was similar until 63 days after treatment (DAT), but the values for IR80 trees began to decline thereafter. The LWP of WT45 trees decreased from 48 DAT. Temporal variations in leaf water content (LWC) was similar to that of LWP, except for two abrupt decreases in IR80 trees. The LWC of WT45 trees began to decrease from 59 DAT, and this occurred 2 weeks after the reduction in LWP. Average shoot length of IR50 trees was greater than that of IR80 and WT45 trees. The results of this study provided water use and crop coefficients for apple trees in relation to soil moisture regimes under temperate climate.     

寒地黑土区玉米高效调亏灌溉制度的试验研究

通过筒测试验,研究了玉米最佳的水分调亏阶段以及各调亏阶段亏水程度的最佳上、下限阈值。结果表明,抽穗开花期水分亏缺对产量影响最大,其次是拔节期,苗期水分亏缺对产量影响最小。苗期、拔节期和抽穗开花期水分亏缺程度分别为50%FC～60%FC、65%FC～75%FC和65%FC～75%FC的灌溉处理是最佳调亏灌溉方案,产量与水分利用效率比正常灌溉处理提高了8%、12.6%。