摘要: Wireless sensor network applications often require a scalable time synchronization with the environment and communicating. Most of time synchronization algorithms are based on hierarchical structure and the precision is promoted at the expense of more complicated calculation. At the same time, the time synchronous is slower on the whole network because of the worse channel collision. This paper presents a novel time synchronization algorithm on the basis of synchronizer of clustering architecture. We adopt the improved RBS approach and introduce the synchronizer as to reducing messages’ overhead efficiently. Finally, performance of this algorithm is illustrated by a simulation experiment.
摘要: This paper presents an improved ant colony algorithm to plan an optimal collision-free path for mobile robot in complicated static environment. Based on the work space model with grid method, simulated foraging behavior of ants and to serve the mobile robot path planning, update the conventional ant colony algorithm with some special functions. To avoid mobile robot path deadlock, a dead-corner table is established and the penalty function is used to update the trail intensity when an ant explores a dead—corner in the path searching. The simulation results show that the algorithm can improve performance of path planning obviously, and the algorithm is simple and effective.
摘要: To better apply ERP, it is necessary to understand its developing rules and influencing factors in the diffusion process. Firstly, properties of ERP diffusion are analyzed, and its diffusion mechanism is discussed. Secondly, under some assumptions, a nonlinear differential model is constructed, in which three kinds of enterprises are considered, and government is regarded as an important factor. Thirdly, the model is analyzed, and qualitative results are given. Finally, the application of the diffusion model is exemplified and simulated by Vensim, and the parameter influence is given. This study assists enterprises to analyze trends of ERP and make reasonable decisions, and provides theory basis for government strategies.
摘要: An image encryption algorithm based on self-adaptive and chaos theory is presented. The scrambling transformation is completed with Logistic chaos and S-box first. Then self-adaptive image encryption scheme is used to deal with gray transformation for each pixel and image encryption is finished at last. Theoretical analyses and simulated experiment show that the proposed image encryption algorithm provides perfect results, larger key space, simple and easy to be implemented and fast running speed, so this encryption algorithm has excellent performance against many kinds of attacks and has strong practicality.
摘要: Based on analysis of the micro-surface and kinematical formulas of elliptical vibration cutting(EVC), the paper presents that frequency and amplitude of vibration parameter affect surface roughness, forming accuracy and machining efficiency of weak rigidity workpiece: increase vibration frequency are result in lower vibration cutting duty cycle , lower cutting force, advancer critical speed, so advance forming accuracy and machining efficiency; decrease amplitude are result in reduce the height of vibration ripples in cutting direction , so improve surface roughness. Experiences of cutting the weak rigidity workpiece by the designed double bending hybrid vibration high transducer, verified that the high frequency elliptical vibration cutting are proved more conducive to machining weak rigidity workpiece.
摘要: This paper investigates the mobile phone’s interference to the 183.31 GHz receivers of the MWHS (Microwave Humidity Sounder) in the FY-3 Meteorological Satellite by a set of related experiments, by which way finds the interfering path. And it analyses the influence of the mobile station’s interference to the orbiting Space-borne Microwave Radiometer in theory. The factors related to the jamming distance and their forces are analyzed. The way to prevent and resolve the interference is proposed and it has been proved by the experiment.
摘要: High speed machining (HSM) features in high efficiency, high precision, high flexibility and high quality. The key techniques on HSM such as linear interpolation, circular interpolation, cubic B-spline curve interpolation, non-uniform rational B-spline (NURBS) curve interpolation and their respective characteristics are paid more attention and expatiated. Circle arcs are approximated by using intersecting polygons instead of general inscribed polygons. NURBS interpolation algorithms can reduce feedrate fluctuation and improve machining accuracy.
摘要: At present, high speed machining (HSM) features in high efficiency, high precision, high flexibility and high quality. HSM technology involves many factors, including cutting mechanisms, machining performance, tool path and other aspects. The key techniques on HSM such as linear interpolation, circular interpolation, cubic B-spline curve interpolation, non-uniform rational B-spline (NURBS) curve interpolation and their respective characteristics are paid more attention and expatiated.
摘要: Alloys were produced by casting of Cu-Al-Fe-Be and Cu-Al-Fe-Ni aluminum bronzes and aged. The microstructures and mechanical properties were evaluated. The results indicated that solution and aging treatment can significantly improve the plasticity of Cu-Al-Fe-Be and Cu-Al-Fe-Ni, while the strength and hardness remained in the quenched level. Extending the aging time can effectively enhance the mechanical properties of alloys, and the longer the aging time, the higher the electric resistance of alloys. According to the results, the mechanical properties of the Cu-Al-Fe-Be alloy can be improved remarkably by solution treatment for 120 min at 950°C, followed by aging treatment for 120 min at 350°C, and quenched. While the most suitable heat treatment for the Cu-Al-Fe-Ni alloy was solution treatment 120 min at 950°C, followed by aging for 120 min at 450°C, and quenched. The experimental result also suggested that the Cu-Al-Fe-Be alloy possessed higher hardness and tensile strength compared to the Cu-Al-Fe-Ni alloy.
摘要: The forward kinematics of wire-driven parallel manipulator CRPM(Completely Restrained Position Mechanism) for aircraft wind tunnels is presented. Based on parameter GCI of workspace performance for the parallel manipulator is proposed, and the structure dimension by instance is optimized. The optimal tension distributing of CRPM is theoretically solved, based on effect coefficient harmonic resolution and energy optimal resolution equations are established which are showed by very simple expression.