针对带时间窗的同时取送货车辆路径问题(vehicle routing problem with simultaneous pickup-delivery and time windows,VRPSPDTW),构建了以车辆使用成本、车辆行驶距离成本总支出最小化的路径优化数学模型,提出自适应头脑风暴算法(ada...针对带时间窗的同时取送货车辆路径问题(vehicle routing problem with simultaneous pickup-delivery and time windows,VRPSPDTW),构建了以车辆使用成本、车辆行驶距离成本总支出最小化的路径优化数学模型,提出自适应头脑风暴算法(adaptive brain storm optimization,ABSO)进行求解。全局搜索阶段,采用多项惩罚方式扩大搜索区域,并使用聚类及三种路径搜索策略进行全局搜索;局部搜索阶段,将六种破坏-修复算子作为备选集合,进而设计自适应动态选择邻域搜索机制,增强局部搜索效能。选取测试数据集和实际案例对算法性能进行测试,实验结果表明针对小规模标准算例,所提算法全部取得了当前已知最优解;对于大规模标准算例,通过与遗传算法、并行模拟退火算法、离散布谷鸟算法对比,所提算法实验计算结果有7.52%~12.03%的提升;对于实际案例,所提算法在收敛速度和寻优能力方面均展示出优越性,充分验证了所提算法对解决VRPSPDTW问题的有效性。展开更多
Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid ...Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid coupling relationship into FLAC3D internal flow models is presented according to fluid-solid coupling theory and strength criterion. A calculation model of numerical analysis was established, and the influences of mining pressure and plastic damage to pore water pressure and seepage vector change rule were studied. The results show that collapse column is the main channel of confined water seepage upward. The impact is not big when the workface is away from the collapse column. But when the workface is nearing a collapse column, there will be a seepage channel on a side near the workface, in which seepage vector and head are comparatively large. With workface pushing through collapse column, the seepage channel transfers to the other side of the column. In addition, when the plastic damage area within the collapse column breaks through, a "pipeline flow" will be formed within the column, and seepage field will change remarkably and the possibility of water bursting will be greater.展开更多
文摘目的探讨扁平足病人中特发性脊柱侧凸(idiopathic scoliosis,IS)的发病情况及影像学特征,分析扁平足病人合并IS的危险因素。方法回顾性分析2021年10月至2023年3月于武汉儿童医院就诊的608例扁平足病人的一般情况和影像学资料,统计扁平足病人中IS的发病率,采用秩和检验比较IS病人与非IS病人、IS中Cobb角>20°病人与Cobb角≤20°病人的一般情况及足影像学参数。采用单因素分析IS病人与非IS病人、IS中Cobb角>20°病人与Cobb角≤20°病人左足外翻角(hallux valgus angle,HVA)、右足HVA、左足(侧位)距骨第1跖骨角(Meary’s angle,MA)、右足MA、HVA差值、MA差值等指标,将P<0.20的指标纳入多因素Logistic回归分析,评估扁平足病人发生IS的危险因素,扁平足合并IS病人Cobb角>20°的危险因素。结果608例扁平足病人中,发生IS的有67例(67/608,11.01%)。扁平足合并IS病人与非IS病人比较,存在双侧外翻角不对称和双侧足弓不对称,差异均有统计学意义(P<0.05)。大于10岁病人(OR=2.866,95%CI:1.683~4.881,P<0.001),女性病人(OR=1.892,95%CI:1.121~3.193,P=0.017),双侧足弓不对称的扁平足病人(OR=1.194,95%CI:1.023~1.393,P=0.025),有更高的IS患病风险。IS病人Cobb角>20°病人左足足弓水平低于Cobb角≤20°病人(P=0.019)。结论IS在扁平足病人中的发病率可能较正常人群发病率高。扁平足合并IS病人存在双侧足形态不对称,包括双侧外翻角不对称及双侧足弓不对称,且双侧足弓不对称是扁平足合并IS的危险因素。
文摘针对带时间窗的同时取送货车辆路径问题(vehicle routing problem with simultaneous pickup-delivery and time windows,VRPSPDTW),构建了以车辆使用成本、车辆行驶距离成本总支出最小化的路径优化数学模型,提出自适应头脑风暴算法(adaptive brain storm optimization,ABSO)进行求解。全局搜索阶段,采用多项惩罚方式扩大搜索区域,并使用聚类及三种路径搜索策略进行全局搜索;局部搜索阶段,将六种破坏-修复算子作为备选集合,进而设计自适应动态选择邻域搜索机制,增强局部搜索效能。选取测试数据集和实际案例对算法性能进行测试,实验结果表明针对小规模标准算例,所提算法全部取得了当前已知最优解;对于大规模标准算例,通过与遗传算法、并行模拟退火算法、离散布谷鸟算法对比,所提算法实验计算结果有7.52%~12.03%的提升;对于实际案例,所提算法在收敛速度和寻优能力方面均展示出优越性,充分验证了所提算法对解决VRPSPDTW问题的有效性。
基金the financial support for this work by the National Key Basic Research and Development Program of China (No. 2010CB226805)the National Natural Science Foundation of China (No. 0874103)the Natural Science Foundation of Jiangsu Province (No. BK2008135)
文摘Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid coupling relationship into FLAC3D internal flow models is presented according to fluid-solid coupling theory and strength criterion. A calculation model of numerical analysis was established, and the influences of mining pressure and plastic damage to pore water pressure and seepage vector change rule were studied. The results show that collapse column is the main channel of confined water seepage upward. The impact is not big when the workface is away from the collapse column. But when the workface is nearing a collapse column, there will be a seepage channel on a side near the workface, in which seepage vector and head are comparatively large. With workface pushing through collapse column, the seepage channel transfers to the other side of the column. In addition, when the plastic damage area within the collapse column breaks through, a "pipeline flow" will be formed within the column, and seepage field will change remarkably and the possibility of water bursting will be greater.
