基于D-S理论的延期支付与存货质押业务决策模型

由于市场的不确定性,延期支付货款和存货质押融资中存在诸多不确定因素,使得资金需求企业难以做出有效的选择。针对此问题,从资金需求企业利润最大化的角度出发,首先分别给出了延期支付和存货质押两种业务下的企业利润模型,进而基于D-S理论建立了两种业务的决策模型。该模型以存货质押和延期支付业务下企业利润差额为目标函数,根据证据推理,以信任函数和似然函数构造出利润差额的上下界概率分布,并据此给出两种业务的决策依据。算例分析表明,对资金需求企业来说,存货质押融资业务并不一定优于延期支付,在特定的市场环境下,需要利用本文提出的模型进行定量计算,从而做出最优的选择。     

混合不确定性下基于区间证据随机抽样的统一赋权法

由于评价问题的复杂性,以及专家知识和经验的局限性,群决策信息中往往同时包含不同程度的不确定性。在区间证据理论框架下对认知不确定性信息、多区间概率信息、不完全信息等混合不确定信息进行统一表示,进而根据区间证据间的相似度对群决策信息进行融合;采用区间数对评语等级进行定量化,并根据融合结果构造个指标重要程度的概率分布函数;最后通过概率分布函数的蒙特卡洛随机抽样确定指标权重。算例分析结果表明了新方法的有效性。     

Effect of substrate curvature on thickness distribution of polydimethylsiloxane thin film in spin coating process

The polymer spin coating is critical in flexible electronic manufaction and micro-electro-mechanical system(MEMS)devices due to its simple operation, and uniformly coated layers. Some researchers focus on the effects of spin coating parameters such as wafer rotating speed, the viscosity of the coating liquid and solvent evaporation on final film thickness.In this work, the influence of substrate curvature on film thickness distribution is considered. A new parameter which represents the edge bead effect ratio(re) is proposed to investigate the influence factor of edge bead effect. Several operation parameters including the curvature of the substrate and the wafer-spin speed are taken into account to study the effects on the film thickness uniformity and edge-bead ratio. The morphologies and film thickness values of the spin-coated PDMS films under various substrate curvatures and coating speeds are measured with laser confocal microscopy. According to the results, both the convex and concave substrate will help to reduce the edge-bead effect significantly and thin film with better surface morphology can be obtained at high spin speed. Additionally, the relationship between the edge-bead ratio and the thin film thickness is like parabolic curve instead of linear dependence. This work may contribute to the mass production of flexible electronic devices.