In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the enviro...In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the environment are increasingly complex, thus it has greater demands on project managers and cost managers that deliver processes on time. However the process of construction is limited to unforeseeable and variable factors, resulting from many sources. The aim of the report is to analyze determining factors about causing budget overrun and time delays by reviewing and identifying past cases. Furthermore, the construction process is made up of three critical phases, i.e. conception, design, construction. Generally, the majority of time delays and cost overrun happen in the period of construction, where many factors are always unforeseeable, and time delays usually associate with cost overruns. （Chan and Kumaraswamy, 1997）展开更多
A functional central limit theorem is proved for the centered occupation time process of the super α-stable processes in the finite dimensional distribution sense. For the intermediate dimensions α < d < 2α (...A functional central limit theorem is proved for the centered occupation time process of the super α-stable processes in the finite dimensional distribution sense. For the intermediate dimensions α < d < 2α (0 < α ≤ 2), the limiting process is a Gaussian process, whose covariance is specified; for the critical dimension d= 2α and higher dimensions d < 2α, the limiting process is Brownian motion.展开更多
A class of superprocesses which dies out is investigated.Under the condition of norextinction, a new superprocess is constructed,its life time is infinite, and its distribution is determined by the moment function. Se...A class of superprocesses which dies out is investigated.Under the condition of norextinction, a new superprocess is constructed,its life time is infinite, and its distribution is determined by the moment function. Several limit theorems about this superprocess and its occupation time process are obtained.展开更多
When femtosecond （fs） timeresolved experiments are used to study ultrafast processes, quantum beat phenomena are often observed. In this paper, to analyze the fs timeresolved spectra, we will present the density mat...When femtosecond （fs） timeresolved experiments are used to study ultrafast processes, quantum beat phenomena are often observed. In this paper, to analyze the fs timeresolved spectra, we will present the density matrix method, a powerful theoretical technique, which describes the dynamics of population and coherence of the system. How to employ it to study the pumpprobe experiments and fs ultrafast processes is described. The transition of pyrazine is used as an example to demonstrate the application of the density matrix method. Recently, Suzuki＇s group have employed the 22 fs time resolution laser to study the dynamics of the state of pyrazine. In this case, conical intersection is commonly believed to play an important role in this nonadiabatic process. How to treat the effect of conical intersection on nonadiabatic processes and fs timeresolved spectra is presented. Another important ultrafast process, vibrational relaxation, which takes place in subps and ps range and has never been carefully studied, is treated in this paper. The vibrational relaxation in water dimer is chosen to demonstrate the calculation. It should be noted that the vibrational relaxation of （H20）2 has not been experimentally studied but it can be accomplished by the pump-probe experiments.展开更多
Under condition of four potential fields, equations of motion and fluctuations in imaginary time are utilized to analytically derive the basic and fluctuating periodic instantons. It is shown that the basic instantons...Under condition of four potential fields, equations of motion and fluctuations in imaginary time are utilized to analytically derive the basic and fluctuating periodic instantons. It is shown that the basic instantons satisfy the elliptic or simple pendulum equations and their solutions are Jacobi elliptic functions, and fluctuating periodic instantons satisfy the Lam′e equation and their solutions are Lame functions. These results indicate that there exists the common solution family for different potential fields which are called the super-symmetry family.展开更多
文摘In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the environment are increasingly complex, thus it has greater demands on project managers and cost managers that deliver processes on time. However the process of construction is limited to unforeseeable and variable factors, resulting from many sources. The aim of the report is to analyze determining factors about causing budget overrun and time delays by reviewing and identifying past cases. Furthermore, the construction process is made up of three critical phases, i.e. conception, design, construction. Generally, the majority of time delays and cost overrun happen in the period of construction, where many factors are always unforeseeable, and time delays usually associate with cost overruns. （Chan and Kumaraswamy, 1997）
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.10101005 and 10121101)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘A functional central limit theorem is proved for the centered occupation time process of the super α-stable processes in the finite dimensional distribution sense. For the intermediate dimensions α < d < 2α (0 < α ≤ 2), the limiting process is a Gaussian process, whose covariance is specified; for the critical dimension d= 2α and higher dimensions d < 2α, the limiting process is Brownian motion.
文摘A class of superprocesses which dies out is investigated.Under the condition of norextinction, a new superprocess is constructed,its life time is infinite, and its distribution is determined by the moment function. Several limit theorems about this superprocess and its occupation time process are obtained.
文摘When femtosecond （fs） timeresolved experiments are used to study ultrafast processes, quantum beat phenomena are often observed. In this paper, to analyze the fs timeresolved spectra, we will present the density matrix method, a powerful theoretical technique, which describes the dynamics of population and coherence of the system. How to employ it to study the pumpprobe experiments and fs ultrafast processes is described. The transition of pyrazine is used as an example to demonstrate the application of the density matrix method. Recently, Suzuki＇s group have employed the 22 fs time resolution laser to study the dynamics of the state of pyrazine. In this case, conical intersection is commonly believed to play an important role in this nonadiabatic process. How to treat the effect of conical intersection on nonadiabatic processes and fs timeresolved spectra is presented. Another important ultrafast process, vibrational relaxation, which takes place in subps and ps range and has never been carefully studied, is treated in this paper. The vibrational relaxation in water dimer is chosen to demonstrate the calculation. It should be noted that the vibrational relaxation of （H20）2 has not been experimentally studied but it can be accomplished by the pump-probe experiments.
基金Supportted by the National Natural Science Foundation of China under Grant No.40975027
文摘Under condition of four potential fields, equations of motion and fluctuations in imaginary time are utilized to analytically derive the basic and fluctuating periodic instantons. It is shown that the basic instantons satisfy the elliptic or simple pendulum equations and their solutions are Jacobi elliptic functions, and fluctuating periodic instantons satisfy the Lam′e equation and their solutions are Lame functions. These results indicate that there exists the common solution family for different potential fields which are called the super-symmetry family.
