Zhi Qiang Xu

A Survey on Coverage Control Technology in Wireless Sensor Network

Deployment and coverage, studied how to effectively place and control of sensor nodes and to make WSN covered the monitoring area with the purpose of minimum the energy consumption and prolonging the network life cycle under the premise of guarantee the quality of service (QOS),are the primary problems for construction wireless sensor network. This paper analyzes important factors for resolve the coverage problem such as sensing models and deployment way, followed survey the state-of-the art coverage contro1 techniques and presents an overview and analysis of the solution proposed in recent research literature, Further research directions are pointed out in the end.

Load Spectrum Compilation Based on Nonparametric Statistical Extrapolation

Considering the special load characteristics of the wheel loader, thispaper focus on compiling the load spectrum of the transmission of the wheelloader using the nonparametric statistical extrapolation method (NSEM). In thisprocess, the determination of the kernel function shape is the critical issue,which has been discussed in detail. Before extrapolating the sample loadspectrum, the signal denoising of the field-tested time-history load signals isperformed. After that, the sample load cycles are obtained using the rainflowcounting method and the corresponding kernel function shape is determined. Thenthe NSEM of rainflow matrix is proposed, by which the whole-life load spectrumis estimated. The proposed extrapolation method can well realize the estimationof the load cycles that do not appear in sample load cycles but may exist inthe whole-life load history.

Determination Method of a Proper Small-Load-Omitting Criterion Based on the Extreme Load

A crucial step to obtain a reliable fatigue life prediction is to determine a proper small load threshold below which the cycles at small loads or stresses with high frequency causing little fatigue damage are truncated from the original load time history. By taking both the peak over threshold theory and the endurance limit threshold into account, a proper small load threshold is proposed in this paper. The optimal threshold should be high enough to remove the high-frequency small cycles and low enough to minimize the loss of the fatigue damage which maybe be truncated by the empirical small-load omitting threshold. Based on this proper threshold, the fatigue life prediction will be more reliable.

Study on the Basic Problems of Dynamics by Induction and Generalization

The relationship between the kineticsof the movement and the role of an object on the object,the force,the kinetics of the basic of the theoretical basis of the whole dynamis is established on the basis of the movement of a large amount of observations and experiments. Dynamic problem is extensive, only common collision vibration in our lives--has the gap or motion constraints between mechanical components of a kinetic phenomenon that repeated exposure. It is widely present in the machinery, aviation, aerospace, military, traffic, and energy systems ,typical examples : gear Vice heat exchange pipes its support , stretch and docking components of the spatial structure, the movement of the robot joints mechanical tools, contain gap mechanical systems, print machinery, mechanical shock , impact shock absorber and cutting machinery utilization cycle force loaded collision Rub between static and dynamic components of the rotor system. Guns , railway wheel and rail with rear seat features motion constraints between mechanical systems , and so on . To help the readers grasp the basic concepts of good dynamics , the basic law , improve readers analyze prolems and problem-solving abilities , on the basis of summing up the experiece of many years practice . Kinetics basic proble summarizd summary . Take advantage of the esperience and understanding of the issure in the practical resaerch.

A Review of Condition Monitoring and Fault Diagnosis of Wind Turbine Gearbox Using Signal Processing

Due to gearbox is one of the high failure rate component in the wind turbine, the research of it has been paid wide attention in recent years. This paper reviewed the two aspects about the wind turbine gearbox. First, some signal process methods including how to determine the threshold were summarized. Then, the condition monitoring and fault diagnosis of gearbox were reviewed using the measured signals. These researches are benefited for reducing economic losses which is caused by the gearbox failure. Based on the above reviews, this paper gives some developmental direction.