2019, 46(8):117-123.
Abstract:As the scale of tasks in the cloud environment continues to expand, the problem of high energy consumption in cloud computing centers has become increasingly prominent. In order to solve the problem of task assignment in a cloud environment and to effectively reduce energy consumption, a Modified Particle Swarm Optimization algorithm (M-PSO) was proposed. First, a cloud computing energy consumption model, which takes into account the processors execution energy consumption and task transmission energy consumption, was introduced. Based on the model, the task assignment problem was defined and described, and the particle swarm optimization algorithm was used to solve this problem. In addition, a dynamically adjusted inertia weight coefficient function was constructed to overcome the local optimization and slow convergence problem of the standard PSO algorithm, and the strategy can effectively improve the system performance. Finally, the performance of the introduced algorithm model was evaluated by simulation experiments. The results show that the M-PSO algorithm can effectively reduce the total energy consumption of the system compared with other algorithms.
2016, 43(7):25-31.
Abstract:A prestressed concrete-steel hybrid tower structure was proposed to replace a conventional 2 MW steel tubular wind turbine tower structure. The height and section size of the prestressed concrete-steel hybrid tower were optimized by an updated partial swarm optimization algorithm, where the cost was taken as the optimal objective function, and the constraint conditions including the strength, stability and the stiffness of the prestressed concrete and steel tubular segments, as well as the fatigue, natural frequency, and the maximum top deflection of the hybrid tower structure were considered, but the shape of the tower was kept unchanged. The optimization results show that the total construction cost of the prestressed concrete-steel hybrid wind turbine tower satisfying all of the constraint considerations is about 27 % less than that of the conventional steel tubular wind tower.
