基于多项式混沌展开的冲压不确定性分析

为分析冲压过程的不确定性,提出基于多项式混沌展开的分析方法,首先根据生产现场实际情况,确定冲压工艺设计变量的概率分布类型,并计算对应的一维正交多项式基底;然后利用PCE展开原则,生成冲压成形评价指标的多维正交多项式,在此基础上计算评价指标的统计矩,评估设计变量对评价指标波动的贡献率;最后运用蒙特卡洛法拟合生成评价指标的累积分布函数,获得更详细的冲压过程不确定性定量评估结果,并以端盖零件为例进行冲压不确定性分析。结果表明:该方法合理、有效,能够准确评估冲压过程的不确定性。

Detection Tool for Unbalanced Bids

Unbalanced bidding is a cash flow management strategy that is recognized as an illegal/disqualifying practice by public owners;and unethical practice by most private owners. This practice provides the awarded bidder with unjustified advantages at the expense of the owner. Unfortunately, limited tools and techniques are currently available to identify and detect unbalanced bids during the evaluation process. This paper presents an innovative detection tool to identify unbalanced bids in unit price contracts during the bid evaluation process. The proposed technique develops BMDI graphs to visualize total markup variation patterns during the project lifetime to detect unbalanced bids. The proposed method also uses Monte Carlo simulation to take in consideration the impact of cost uncertainties and risks. An illustrative example was presented to show the capabilities and features of the proposed method in determining the status of submitted bids during the evaluation process.

基于差异可靠性约束的中压有源配电系统供电能力评估

针对传统供电能力评估方法中难以在负荷高峰期全网N-1准则的基础上满足用户差异化可靠性需求并同时计及DG与储能接入影响的问题,提出了一种新的中压有源配电系统供电能力评估方法。首先,构建了以最大供电能力为目标、不同用户的差异化可靠性需求为主要约束的含分布式光伏序列与蓄电池两级配电系统供电能力评估模型。其次,考虑分布式光伏与蓄电池的接入,建立了基于准序贯蒙特卡洛模拟的变电站与中压配电网一体化可靠性评估方法。再次,建立了基于遗传算法的供电能力评估模型的优化方法,并通过算例验证了本文方法的有效性和实用性。