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In order to improve the development quality of China’s freight logistics, improve the efficiency of resource utilization, the article uses ARIMA-SVR-DEA method to forecast the freight logistics in our country delayed data and calculate the delayed freight logistics efficiency, and the results show that the unreasonable utilization of resources is the reason for the inefficiency of freight logistics, which provides a reference for the development of freight logistics industry.

Cooccurrence relation extraction of abundant tags is very significant f or information retrieve and tag recommendation. This paper presents a parallel extraction method of tag cooccurrence relatio n based on cloud computing. At last, two experiments show that the parallel extraction method can improve the performance of retrievals greatly and have good scalability. The research may play a role in the facilitative effect on the expanding application of social tagging s ystem with abundant, multiplex, complex annotated data.

This paper presents a 4-DOF (3T1R: three-translational and one rotational degrees of freedom) parallel mechanism with passive spherical joints, which has better stiffness than the other ones with just prismatic and revolute joints. Firstly, structure description is given. And a complete study regarding motion characteristics is done by analytical method. Then the kinematics of the 4-DOF parallel manipulator, which includes inverse and forward solutions, is studied in detail by numerical method. The Jacobian matrix of the parallel manipulator is also derived. Based on the Jacobian matrix, singularity analysis of the parallel mechanism has been described clearly. All prismatic actuators of the 4-DOF parallel manipulator are parallel to each other, enables it to have an independent Z motion—only limited by the stroke of the prismatic actuators. So the parallel manipulator has the identical performance along the direction of the actuated linear slides. The 4-DOF parallel manipulator is characterized by elevated dynamical capabilities having its actuators at base.

Optimizing the NACA0015 airfoil which is widely applied in small-scale vertical axis wind turbine to make it has a better aerodynamic performance. In the optimization process, using CST parameterization method to perturb the airfoil geometry, the thickness and camber of the airfoil are selected as the constraint, and the value of the maximum tangential force coefficient is chosen as the objective function, the genetic algorithm based on non-dominated sorting (NSGA-II)is selected as an optimization method, calculates the aerodynamic performance of the airfoil by applying the approach of combining XFOIL program and Viterna-Corrigan post-stall mode ,and establishes the optimizing process by the optimization software modefrontier for NACA0015 airfoil’s muti-point optimization, validate the airfoil’s performance with CFD finally. The result illustrates that, by comparing with the NACA0015 airfoil, the optimized airfoil’s lift to drag ratio is improved over a wide range of attack angles, the stall performance is more gentle. The maximum lift coefficient, the maximum lift-drag ratio and the maximum tangential force coefficient are increased by 7.5%,9 and 8.87%, respectively. The optimized airfoil has a wide variable condition performance, more suitable for the operating conditions of a vertical axis wind turbine. Finally, predict the rotor efficiency with optimized airfoil and NACA0015 airfoil for different tip speed ratios and different solidities with multiple streamtube model, the result shows the rotor with optimized airfoil has a higher efficiency. Keyword: vertical axis wind turbine; CST parameterization; NSGA-II; airfoil; optimization; multiple streamtube model

By turning to the theory of elastic thin plates, a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished, in which formulaes were deduced for the calculation of the stress distribution. When the main roof stress distribution was characterized, the failure form of the roof in the long wall coal seam under work was given with the failure criterion deduced. The deduced failure criterion was then applied to the No.3232(3) face of the Lizuizi Coal Mine; the first pressure for the working face was accurately predicted. Results of the field application show that the main roof of the severely inclined coal seam under long wall working breaks in the O-X pattern, which is basically in accordance with the reality.

A study of the characteristics of the accumulative rock failure and its evolution by application of the group renormalization method were presented. In addition, the interaction and long-range correlated effects between the immediate neighboring units was studied. The concept of mechanical transference for model OFC, employed in the study of self-organized criticality, and the coefficient α were introduced into the calculation model for group renormalization. With the introduction, mechanisms for the drastic increase and decrease of failure intensity of rocks were investigated under similar macro-conditions.

According to the geological and mining technical conditions of No.18128 sublevel caving face with suspend-shift support, the first working face of the working area, the distribution laws of abutment pressure were studied by jointly employing FlAC3D numerical simulations and field tests. With the full consideration of these laws and the service timelimit of the mining district, the optimal location of the terminal mining line, should be 60 m away from the W4-B8 track dip, which was 20 m shorter than the 80 m distance determined according to traditional experiences. The retained coal safety pillar for the protecting of dips, already proved by the industrial practice, can not only improve the rate of coal recovery and satisfy the subsequent service requirement for the following working faces, but also decrease the maintaining expenditure and thus increase profits.

Associate researcherWang (1935-) is Associate Director of the Institute of Archaeology of Shanxi Province and standing member of Shanxi Archaeological Association. Since he graduated from the geology department of the Beijing Geology College in 1961, he has been engaged in the study of paleo-anthropology and paleolithic archaeology. He was in charge of the excavation of Dingcun site in 1984. His main treatises are: «Archaeological Reconnaissances at Hsiach'uan in Chinshui County, Shanxi Province», «Microliths from Xueguan Country, Shanxi».Zhu Xiaodong (1965-0000) is a practice researcher of the Institute of Archeology of Shanxi Province, who graduated from the archaeology department of Beijing University in 1987, and took part in the excavation of Gold-Ox Mount site in Liaoning Province.