Multi-Mode Resource Constrained Project Scheduling Models for Progress and Equal Time Interval Payments

This study utilizes a time-precedence network technique to construct two models of multi-mode resource constrained project scheduling problem with discounted cash flows （MRCPSPDCF）, individually including the progress payment （PP） and the payment at an equal time interval （ETI）. The objective of each model is to maximize the net present value （NPV） for all cash flows in the project, subject to the related operational constraints. The models are characterized as NP-hard. A heuristic algorithm, coupled with two upper bound solutions, is proposed to efficiently solve the models and evaluate the heuristic algorithm performance which was not performed in past studies. The results show that the performance of proposed models and heuristic algorithm is good.

锁定模型和企业集聚分析

集聚是指在特定的领域里相互联系的公司和机构在地理上的集中。近年来,全球制造业在向中国聚集的同时,制造业在我国各地并不是均衡发展,在空间上明显存在企业集聚现象,如深圳、东莞、江苏昆山、浙江嘉兴等地。本文主要从经济学角度,在对企业集聚现象进行一般理性分析基础上,利用锁定模型及现金流贴现模型进行模型分析,其中将影响投资决策的相关因素分解为显性的静态因素和隐性的动态因素。最后,本文认为当前各级地方政府在改变显性静态因素方面难以有较大差别情况下,不断改善隐性动态因素是地方政府在吸引投资项目和发展制造业应采取的主要措施。