Probabilistic and interval reliability design of the composite pressure vessel

Considering the randomness or interval character of physical parameters and applied loads of composite pressure vessels (COPV), the COPV reliability-analyzing model is built. And then the computational expressions for the mean value, standard deviation and deviation of fiber stress are deduced by the random factor method. The probabilistic and interval reliability designs on COPV are implemented by utilizing the probabilistic method and interval method combined with the improved particle swarm optimization (PSO) algorithm, respectively. The influence of fluctuation of structure uncertain parameters on COPV design thickness is inspected. Finally, examples are given to demonstrate that both probabilistic and interval reliability methods can satisfy the safety requirement and both are of higher rationality than the traditional safety factor method. And probabilistic method has a lower relative error but a higher computational complexity contrasted with the interval method.     

An automatic parameter calibration method for the SWAT model in runoff simulation

Runoff simulation is highly significant for hydrological monitoring, flood peak simulation, water resource management, and basin protection. Runoff simulation by distributed hydrological models, such as the soil and water assessment tool (SWAT) model which is the most widely used, is becoming a hotspot for hydrological forecasting research. However, parameter calibration is inefficient and inaccurate for the SWAT model. An automatic parameter calibration (APC) method of the SWAT model was developed by hybrid of the genetic algorithm (GA) and particle swarm optimization (PSO). Multi‐station and multi‐period runoff simulation and accuracy analysis were conducted in the basin of the Zhangjiang River on the basis of this hybrid algorithm. For example, in the Yaoxiaba Station, the calibration results produced an R² of 0.87 and Nash Sutcliffe efficiency (NSE) index of 0.85, while verification results revealed an R² of 0.83 and NSE of 0.83. Results of this study show that the proposed method can effectively improve the efficiency and simulation accuracy of the model parameters. It can be concluded that the feasibility and applicability of GA‐PSO as an APC method for the SWAT model were confirmed via case studies. The proposed method can provide theoretical guidance for many hydrological research fields, such as hydrological simulation, flood prevention, and forecasting.     

电控柴油机分缸均衡控制算法及试验

柴油机各个气缸的进气量、喷油量、燃烧等存在差异,导致气缸间存在做功差异,直接影响柴油机转速的平稳性以及排放性能等。针对位置式电控柴油机,采用PI闭环控制,通过瞬时转速信号识别并计算各缸的工作差异,利用分缸均衡控制算法对油量进行补偿修正。试验结果显示低转速稳态工况转速波动由7 r/min降至3 r/min,各缸工作不均匀度由±5 r/min降至±2 r/min,在瞬态过程和高转速3 400 r/min时该算法仍然适用有效。     

基于改进Kendall-f算法的发电机定子温度分析

在线监测发电机定子温度可有效发现定子部分过热性故障,如何从检测的温度数据中提取反映定子故障预警的信息是目前国内外研究的热点。该文采用可变窗改进Kendall-f算法处理监测温度数据,提取其变化趋势特征信息;采用偏度分析提取监测温度异常值,从而正确诊断定子过热性故障,仿真分析及实验结果表明该方法有效提高了定子温度监测与预警的准确率。     

复杂系统平均寿命的估计和性质

根据已知的基于最小路径或最小割集复杂系统可靠度函数的解析表达式,给出当子系统寿命分布服从指数分布时,系统平均寿命的表达式.利用这一表达形式,在子系统寿命变量服从指数分布条件下,分别就完全数据和截尾数据两种情况,给出了系统平均寿命的估计,并对估计性质进行了研究.并在完全数据下,给出了估计的渐近分布.     

模具生产联合体加工作业统一调度问题的研究

模具生产联合体是由小规模企业组成的模具设计、制造联盟，由于设备、工装和人员分属于不同的加盟企业，其作业排序过程非常复杂。为此提出一种复合式模具生产联合体的生产排序方法：依据基本优先规则首先完成单一工序作业，然后对多工序作业用改进遗传算法进行工艺优化，求出最优解和次优解，再使用评价函数法选择最佳作业路线。该方法在生产试验中取得了良好的成效．能较好满足模具用户和加盟企业两方面的需要。     

混合室分配板成形工艺及模具设计

对混合室分配板零件介绍了一种落料拉伸成形和立体切沿分割的工艺思路以及模具结构和相关的理论计算 ,在实际应用中获得了好的效果。对同类形状产品 ,尤其是涉及到需要进行立体切沿分割的制件 ,可提供借鉴。     

Dual–primal proximal point algorithms for extended convex programming

This paper presents a class of dual–primal proximal point algorithms (PPAs) for extended convex programming with linear constraints. By choosing appropriate proximal regularization matrices, the application of the general PPA to the equivalent variational inequality of the extended convex programming with linear constraints can result in easy proximal subproblems. In theory, the sequence generated by the general PPA may fail to converge since the proximal regularization matrix is asymmetric sometimes. So we construct descent directions derived from the solution obtained by the general PPA. Different step lengths and descent directions are chosen with the negligible additional computational load. The global convergence of the new algorithms is proved easily based on the fact that the sequences generated are Fejér monotone. Furthermore, we provide a simple proof for the O(1/t) convergence rate of these algorithms.     

一种基于蚁群算法的呼叫中心人力需求计算方法

针对呼叫中心人力需求优化这一离散约束问题,基于Dantzig提出的集合覆盖模型,建立了单技能呼叫中心的人力需求计算线性规划模型,并提出一种基于改进蚁群算法的求解方法.在该方法中,对算法的信息素更新规则进行了修改,并基于MATLAB编程针对实例进行仿真分析.选取统计学指标将算法的仿真结果与遗传算法进行对比,结果表明:基于蚁群算法的方法计算复杂度可行;能够节约人力,且话务员匹配度可满足实际运营需求;为智能算法在呼叫中心人力需求计算问题上的应用研究提供了一种新的解决思路.