In civil engineering, earthwork, prior to the construction of most engineering projects, is a lengthy and time-consuming work involving iterative processes. The cost of many AEC (Architecture, Engineering and Construction) projects is highly dependent on the efficiency of earthworks (e.g. road, embankment, railway and slope engineering). Therefore, designing proper earthwork planning is of importance. This paper simplifies the earthwork allocation problem to Vehicle Route Problem (VRP) which is commonly discussed in the field of transportation and logistics. An optimization model for the earthwork allocation path based on the modified Genetic Algorithm with a self-adaptive mechanism is developed to work out the global optimal hauling path for earthwork. The research results also instruct the initial topographic shaping of the Winter Olympic Skiing Courses Project. Furthermore, this optimization model is highly compatible with other evolutionary algorithms due to its flexibility, therefore, further improvement in this model is feasible and practical.

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In this paper, the mathematical model of threephase four-wire three-level neutral-point-clamped (NPC) voltage source rectifier (VSR) using switching functions is founded and its operating principle analyzed. Then a new nonlinear control law based on Lyapunov's stability theory for the PWM rectifier is presented. With this control law, the converter can be stabilized globally for handling largesignal disturbances, and exhibit good transient response. Also, by designing new three-level sinusoidal PWM method, this paper solves effectively the problem that the neutral point potential of DC-link has triple-harmonic fluctuation resulting from existing three-level SPWM method. Computer simulations of the system confirm the validity of the mathematical model and the effectiveness of the proposed control strategy.I.

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