Facility location problem is a kind of NP-Hard combinational problem.Considering ever-changing demand sites,demand quantity and releasing cost,we formulate a model combining tabu search and FCM(fuzzy clustering method...Facility location problem is a kind of NP-Hard combinational problem.Considering ever-changing demand sites,demand quantity and releasing cost,we formulate a model combining tabu search and FCM(fuzzy clustering method) to solve the capacitated dynamic facility location problem.Some results are achieved and they show that the proposed method is effective.展开更多
The time accuracy of the exponentially accurate Fourier time spectral method（TSM） is examined and compared with a conventional 2nd-order backward difference formula（BDF） method for periodic unsteady flows. In part...The time accuracy of the exponentially accurate Fourier time spectral method（TSM） is examined and compared with a conventional 2nd-order backward difference formula（BDF） method for periodic unsteady flows. In particular, detailed error analysis based on numerical computations is performed on the accuracy of resolving the local pressure coefficient and global integrated force coefficients for smooth subsonic and non-smooth transonic flows with moving shock waves on a pitching airfoil. For smooth subsonic flows, the Fourier TSM method offers a significant accuracy advantage over the BDF method for the prediction of both the local pressure coefficient and integrated force coefficients. For transonic flows where the motion of the discontinuous shock wave contributes significant higherorder harmonic contents to the local pressure fluctuations,a sufficient number of modes must be included before the Fourier TSM provides an advantage over the BDF method.The Fourier TSM, however, still offers better accuracy than the BDF method for integrated force coefficients even for transonic flows. A problem of non-symmetric solutions for symmetric periodic flows due to the use of odd numbers of intervals is uncovered and analyzed. A frequency-searching method is proposed for problems where the frequency is not known a priori. The method is tested on the vortex shedding problem of the flow over a circular cylinder.展开更多
研究绿色同时取送货车辆调度问题,提出改进的遗传禁忌搜索算法(Genetic Algorithm with Tabu Search,GA-TS)求解该问题。模型中,以服务成本、油耗成本和碳排放成本构成的总成本最小为目标,采用了综合模型计算油耗和碳排放成本,引入三角...研究绿色同时取送货车辆调度问题,提出改进的遗传禁忌搜索算法(Genetic Algorithm with Tabu Search,GA-TS)求解该问题。模型中,以服务成本、油耗成本和碳排放成本构成的总成本最小为目标,采用了综合模型计算油耗和碳排放成本,引入三角模糊数来描述客户需求的不确定性,并考虑同时取送货需求。在改进的GA-TS算法中,将惩罚因子引入适应度函数,采用结合精英策略的选择算子,提出结合禁忌搜索算法的变异算子。在案例分析中,采用田口分析法获取合理的参数设置,通过案例结果分析和算法对比分析验证模型和算法的有效性和先进性。展开更多
文摘Facility location problem is a kind of NP-Hard combinational problem.Considering ever-changing demand sites,demand quantity and releasing cost,we formulate a model combining tabu search and FCM(fuzzy clustering method) to solve the capacitated dynamic facility location problem.Some results are achieved and they show that the proposed method is effective.
基金supported by the State Scholarship Fund of the China Scholarship Council (Grant 2009629129)
文摘The time accuracy of the exponentially accurate Fourier time spectral method（TSM） is examined and compared with a conventional 2nd-order backward difference formula（BDF） method for periodic unsteady flows. In particular, detailed error analysis based on numerical computations is performed on the accuracy of resolving the local pressure coefficient and global integrated force coefficients for smooth subsonic and non-smooth transonic flows with moving shock waves on a pitching airfoil. For smooth subsonic flows, the Fourier TSM method offers a significant accuracy advantage over the BDF method for the prediction of both the local pressure coefficient and integrated force coefficients. For transonic flows where the motion of the discontinuous shock wave contributes significant higherorder harmonic contents to the local pressure fluctuations,a sufficient number of modes must be included before the Fourier TSM provides an advantage over the BDF method.The Fourier TSM, however, still offers better accuracy than the BDF method for integrated force coefficients even for transonic flows. A problem of non-symmetric solutions for symmetric periodic flows due to the use of odd numbers of intervals is uncovered and analyzed. A frequency-searching method is proposed for problems where the frequency is not known a priori. The method is tested on the vortex shedding problem of the flow over a circular cylinder.
文摘研究绿色同时取送货车辆调度问题,提出改进的遗传禁忌搜索算法(Genetic Algorithm with Tabu Search,GA-TS)求解该问题。模型中,以服务成本、油耗成本和碳排放成本构成的总成本最小为目标,采用了综合模型计算油耗和碳排放成本,引入三角模糊数来描述客户需求的不确定性,并考虑同时取送货需求。在改进的GA-TS算法中,将惩罚因子引入适应度函数,采用结合精英策略的选择算子,提出结合禁忌搜索算法的变异算子。在案例分析中,采用田口分析法获取合理的参数设置,通过案例结果分析和算法对比分析验证模型和算法的有效性和先进性。
