Time, cost and quality are the three main targets to be controled in project management. However, the control and management of time and cost risk are usually carried out respectively, which will bring such problems a...Time, cost and quality are the three main targets to be controled in project management. However, the control and management of time and cost risk are usually carried out respectively, which will bring such problems as the delay of schedule by reason of the impracticability of cash flow, the money difficulties caused by delay of schedule and so on. In order to control and manage the time and cost risk effectively and simultaneously, a time & cost risk control model based on schedule programme was established with the use of the quantitativemodels of BCWS, BCWP and ACWP in this paper. Subsequently, the analysis of variance for the whole project and the single activity was introduced on the basis of BCWS, BCWP and ACWP so that the project can be controlled and managed effectively. Furthermore, an example given behind in detail expressly illustrated that the model set up above was practicableto project management. However, the method of optimizing the cash flow based on time and cost risk to obtain BCWS should be considered properlyand carefully with respect to the different circumstances of the project, and an efficient and adequate interval report system should be set up on the site of the project.展开更多
A new virtual age repair model with non-uniform aging speed is presented on the basis of Kijima classical virtual age repair models which can be viewed as of uniform aging nature.In this model are included three types...A new virtual age repair model with non-uniform aging speed is presented on the basis of Kijima classical virtual age repair models which can be viewed as of uniform aging nature.In this model are included three types,of perfect,of imperfect and of minimal,all having a non-uniform aging speed.Formulas of expected count of repair and length of working time of these three models are derived,and numerical examples are also given to illustrate and verify obtained theoretical indices.As an extended work,a sketchy model of maintenance time of the non-uniform aging virtual age repair model is discussed.Overall,the three models discussed in the paper,each with non-uniform aging speed,are expansions to existing virtual age repair models,relevant formulas given here are new results,and the systems introduced are without the lifetime distribution assumption,all of which may be expected to improve maintenance work.展开更多
文摘Time, cost and quality are the three main targets to be controled in project management. However, the control and management of time and cost risk are usually carried out respectively, which will bring such problems as the delay of schedule by reason of the impracticability of cash flow, the money difficulties caused by delay of schedule and so on. In order to control and manage the time and cost risk effectively and simultaneously, a time & cost risk control model based on schedule programme was established with the use of the quantitativemodels of BCWS, BCWP and ACWP in this paper. Subsequently, the analysis of variance for the whole project and the single activity was introduced on the basis of BCWS, BCWP and ACWP so that the project can be controlled and managed effectively. Furthermore, an example given behind in detail expressly illustrated that the model set up above was practicableto project management. However, the method of optimizing the cash flow based on time and cost risk to obtain BCWS should be considered properlyand carefully with respect to the different circumstances of the project, and an efficient and adequate interval report system should be set up on the site of the project.
基金Sponsored by the Program for New Century Excellent Talents in University of China(NCET-05-0180)
文摘A new virtual age repair model with non-uniform aging speed is presented on the basis of Kijima classical virtual age repair models which can be viewed as of uniform aging nature.In this model are included three types,of perfect,of imperfect and of minimal,all having a non-uniform aging speed.Formulas of expected count of repair and length of working time of these three models are derived,and numerical examples are also given to illustrate and verify obtained theoretical indices.As an extended work,a sketchy model of maintenance time of the non-uniform aging virtual age repair model is discussed.Overall,the three models discussed in the paper,each with non-uniform aging speed,are expansions to existing virtual age repair models,relevant formulas given here are new results,and the systems introduced are without the lifetime distribution assumption,all of which may be expected to improve maintenance work.
