In order to alleviate the flight congestion in terminal areas(TMAs),it is of great significance to develop an effective method.An arrival sequencing model based on the serial point merge systems(PMSs)is constructed to...In order to alleviate the flight congestion in terminal areas(TMAs),it is of great significance to develop an effective method.An arrival sequencing model based on the serial point merge systems(PMSs)is constructed to improve the operational benefits of arrival flights.The approach of first come first service(FCFS)combined with the method of constraint position shift(CPS)is used as the sequencing strategy.Through the simulated annealing algorithm,the results show that the arrival flights sequencing through serial PMSs has significant advantages in reducing delays and increasing runway throughput especially in the case of high traffic loads.The proposed approach is conducive in promoting the implementation and application of serial PMS.展开更多
In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining...In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining to the quality of the project is needed. The aim of this study is to provide an overview the most common procurement methods used in constructing infrastructure transport projects and analyze how these methods contribute to the desired quality of the final product in relation to client competence. An on-line survey of construction actors was carried out to ascertain quality level of Swedish infrastructure transport projects and determinant factors of quality problems. An equal number of respondents indicated that the quality of infrastructure projects has either increased or remained same level over the past twenty years. Respondents also pointed out lack of client competence that is vital in realizing the desired quality level through proper procurement, monitoring and evaluation procedures. Public clients heavily rely on traditional design-build procurement that requires considerable client involvement of a project. Thus, the association of quality problems and lack of client competence may not be a mere coincidence but an overlooked outcome of current situation.展开更多
基金supported by the National Natural Science Foundation of China(No.U1933119)the Foundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics(No.xcxjh20210703)
文摘In order to alleviate the flight congestion in terminal areas(TMAs),it is of great significance to develop an effective method.An arrival sequencing model based on the serial point merge systems(PMSs)is constructed to improve the operational benefits of arrival flights.The approach of first come first service(FCFS)combined with the method of constraint position shift(CPS)is used as the sequencing strategy.Through the simulated annealing algorithm,the results show that the arrival flights sequencing through serial PMSs has significant advantages in reducing delays and increasing runway throughput especially in the case of high traffic loads.The proposed approach is conducive in promoting the implementation and application of serial PMS.
文摘In order to achieve high quality that not only gives acceptable return value to society but also satisfies the needs of all the stakeholders of infrastructure projects, comprehensive understanding of issues pertaining to the quality of the project is needed. The aim of this study is to provide an overview the most common procurement methods used in constructing infrastructure transport projects and analyze how these methods contribute to the desired quality of the final product in relation to client competence. An on-line survey of construction actors was carried out to ascertain quality level of Swedish infrastructure transport projects and determinant factors of quality problems. An equal number of respondents indicated that the quality of infrastructure projects has either increased or remained same level over the past twenty years. Respondents also pointed out lack of client competence that is vital in realizing the desired quality level through proper procurement, monitoring and evaluation procedures. Public clients heavily rely on traditional design-build procurement that requires considerable client involvement of a project. Thus, the association of quality problems and lack of client competence may not be a mere coincidence but an overlooked outcome of current situation.
