The violation of monotonicity on reliability measures(RMs)usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium(RUE)problem.The swapping algorithms prov...The violation of monotonicity on reliability measures(RMs)usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium(RUE)problem.The swapping algorithms provide a simple and convenient alternative to search traffic equilibrium since they are derivative-free and require weaker monotonicity.However,the existing swapping algorithms are usually based on linear swapping processes which cannot naturally avoid overswapping,and the step-size parameter update methods do not take the swapping feature into account.In this paper,we suggest a self-regulating pairwise swapping algorithm(SRPSA)to search RUE.SRPSA comprises an RM-based pairwise swapping process(RMPSP),a parameter self-diminishing operator and a termination criterion.SRPSA does not need to check the feasibility of either solutions or step-size parameter.It is suggested from the numerical analyses that SRPSA is effective and can swap to the quasi-RUE very fast.Therefore,SRPSA offers a good approach to generate initial points for those superior local search algorithms.展开更多
合理定量描述土壤水盐动态及作物生长过程对于干旱灌区制定适宜的农业用水措施具有重要意义。该文以SWAP(soil water atmosphere plant)模型为基础,采用变活动节点法实现了对土壤融化期的水盐运移模拟,并在根系吸水计算中引入了基于S形...合理定量描述土壤水盐动态及作物生长过程对于干旱灌区制定适宜的农业用水措施具有重要意义。该文以SWAP(soil water atmosphere plant)模型为基础,采用变活动节点法实现了对土壤融化期的水盐运移模拟,并在根系吸水计算中引入了基于S形函数的水盐胁迫计算方法,以修正原SWAP模型对根系吸水的模拟。进一步嵌入了参数与输入数据较少且可以模拟作物生长过程及实际产量的EPIC(environmental policy integrated calculator)作物生长模型,构建了改进的农田尺度土壤水盐动态与作物生长耦合模拟模型-SWAP-EPIC。分别采用宁夏惠农灌区春小麦和春玉米田间试验数据,对SWAP-EPIC模型田间适用性进行了检验。对比分析各层土壤水分与盐分浓度、作物生长指标(叶面积指数、地上部生物量)的模拟值与实测值,结果表明:春小麦和春玉米试验中土壤水分的平均相对误差MRE和均方根误差RMSE均接近于0且模型Nash效率系数NSE值趋近于1,水分模块模拟精度较高,盐分浓度模拟存在略微差异但总体上一致性较好,并且作物生长指标匹配良好;同时,模拟的产量和蒸散发均较为接近实际值,春小麦和春玉米产量模拟相对误差分别为4.9%和3.3%。综上,该文改进的SWAP-EPIC模型可良好地应用于寒旱区农田尺度土壤水盐运移与作物生长耦合模拟。展开更多
基金Projects(71601015,71501013,71471014)supported by the National Natural Science Foundation of ChinaProject(2015JBM060)supported by the Fundamental Research Funds for the Central Universities,China
文摘The violation of monotonicity on reliability measures(RMs)usually makes the mathematical programming algorithms less efficient in solving the reliability-based user equilibrium(RUE)problem.The swapping algorithms provide a simple and convenient alternative to search traffic equilibrium since they are derivative-free and require weaker monotonicity.However,the existing swapping algorithms are usually based on linear swapping processes which cannot naturally avoid overswapping,and the step-size parameter update methods do not take the swapping feature into account.In this paper,we suggest a self-regulating pairwise swapping algorithm(SRPSA)to search RUE.SRPSA comprises an RM-based pairwise swapping process(RMPSP),a parameter self-diminishing operator and a termination criterion.SRPSA does not need to check the feasibility of either solutions or step-size parameter.It is suggested from the numerical analyses that SRPSA is effective and can swap to the quasi-RUE very fast.Therefore,SRPSA offers a good approach to generate initial points for those superior local search algorithms.
