Abstract:The study object of this paper is helical beveloid gears with parallel axis. Based on the gear Mshing Principles and the tooth-surface equations of pinion and gear,the mathematical model of tooth contact is developed under standard installation and installations with center distance error,axis error and multiple error respectively. The MATLAB solver is used to obtain the contact trace and the transmission error under different installing conditions and the comparative analysis is made. The results indicate that this gear drive is sensitive to axis installation errors,it forms the edge contact and cause the periodic transmission error. It can provide the foundation for designs and analysis of this gear transmission.

Abstract:Considering that the transmission system of wind turbine works in complex and changing load environment caused by stochastic wind speed,this paper uses sparse least squares support vector machine(SL-SVM) to simulate wind speed of true wind field,and obtains time-varying wind load caused by stochastic wind speed. The lumped-parameter method is used to develop a dynamic model of planetary gear transmission system of wind turbine coupled with bearing. The model includes the varying wind load,time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing. The numerical method is used to simulate the dynamic performance of planetary gear system of Multibrid Technology Wind Turbine with 1.5 MW rated power. The vibration displacement responses of the transmission system are obtained as well as dynamic meshing force each pair of gear and nonlinear bearing forces. The research can provide a foundation for optimizing dynamic performance and reliable design of gear transmission system of wind generator.

Abstract:This paper proposes a control strategy for the optimal control of the outsourcing production inventory system based on production point and production batch. The statistical probability distribution is used to describe the uncertainty of the production capacity of cooperative enterprises and the transportation time. The optimization model of the control parameters is developed with random production capacity for cooperative enterprises and random transportation time in order to minimize the holding cost,setup cost as well as the cost of production capacity waste. A simulation-based control parameters optimization algorithm is designed to solve the proposed model. The control strategy of production inventory system and the control parameters optimization algorithm proposed are validated by an example. We analyze the influence of the variation of the production point and production batch to the performance of the outsourcing production inventory system.

Abstract:In order to analyze the performance of the electric motorcycle frame structure under working condition of vibration and reduce its weight,the transient finite element analysis model is developed with the theory of transient dynamics,and frame dynamic strength is calculated to obtain the maximum stress and stress distribution of frame under the working condition. On that basis,we establish the optimum model with the target function of the frame’s weight based on the optimal module of Hyperworks,and make optimization design of the frame under intensity and rigidity constraint conditions. The theory analysis and experimental results indicate that the frame has surplus strength and the value of safety factor is high under working condition of vibration ,and the strength of the optimized frame meets the requirements of safety and manufacturing process,meanwhile,the weight of frame is reduced by 12.1%,which shows that the optimization method is reliable and effective for the design of the structure of the frame.

Abstract:This paper proposes a new method of generating a rough cut Numerical Control(NC) codes directly from industrial computerized tomography(CT) slice images for the products which work-piece did not need to be redesigned.The contour structure data of the work-piece are obtained by the threshold segmentation,edge extraction and contour tracing. The inner and outer contours are judged,and the tool radius compensation and the allowance reservation are performed by offsetting the contours according to the judgments. The authors generate the rough cut NC code cut area distinguishing and rough cut path generating in a slice by slice manner. In contour offsetting step, a new approach is proposed to judge inner and outer contours. A software system is developed to generate NC codes. An example is used to verify this approach and results show the feasibility and validity of the approach.

Abstract:This paper proposes a modeling method of the motor broadband equivalent circuit model. The impedance amplitude-frequency characteristics of the motor terminal through measuring are obtained. The impedance amplitude-frequency characteristics are devided into several regions based on its first resonant point information,and the motor broadband circuit topology is developed with each region equaling a resonance unit. The RLC parameters of resonance unit are extracted through frequency and corresponding impedance of the any non-resonant and resonant point in each unit. This proposed method is used to build DC and AC motor broadband equivalent circuit model. Their impedance amplitude-frequency characteristics are simulated by the Saber software. The measurement results and the simulation result of references are compared. The DC motor simulation results coincide with the measurement results in 0.1~50 MHz,and the AC motor is in 0.1~40 MHz. The results show that the motor broadband circuit model is reliable and feasible.

Abstract:Power supply is an important component of LED lighting. Considering the power supply’s lifespan didn’t match LED’s long lifespan by the electrolytic capacitor’s own feature,we propose a step-down transformer topology structure of active ripple compensation based on BUCK circuit. This topology took full advantage of the characteristics of switching power supplies and linear power supplies to replace the traditional electrolytic capacitor filter with the auxiliary active circuitry compensation inductor ripple current. We analyzed the structure and the operation principle of the new topology and confirmed the validity of the new topology. The theoretical analysis and experimental results show that using the topological structure of active ripple compensation can completely compensate inductance’s ripple current,so that the circuit output is DC.

Abstract:The IEC61850 standard and the existing bus protection data model are limited in the definition of data-model about dead-zone protection and charge protection for bus-tie. The paper analyzes the dead-zone protection and charge protection for bus-tie,and the data of input,output and setting based on the latest issued technical specifications intelligent substation. The data models of dead-zone protection and charge protection of bus-tie are developed for PCS915 bus protection. It improves the logic node modeling of bus protection and can provide useful information for the protection data-model configuration of intelligent substations.

Abstract:When the top surface is non-slip solid and the ratio between height and radius of crucible equals 2, the finite-difference method is adopted to carry on three-dimensional numerical simulation on the thermocapillary convection in detached solidification under microgravity. The distributions of velocity and temperature in the melt are obtained as the width of gap in crucible is selected as 0.1, 0.075 and 0.05, respectively. The results show that when the Marangoni number is small, there is one steady toroidal roll cell near the lower free surface, and the flow of melt is steady and weak. With the increase of Marangoni number, the flow is expanded toward the inner part of melt gradually and the velocity of flow on the lower free surface increases. When the Marangoni number exceeds the critical value, the flow of melt becomes unstable.

Abstract:The performance analysis of a transcritical organic Rankine cycle system driven by exhaust heat is presented by using 24 organic working fluids. Four parameters, such as the net power output, thermal efficiency, exergy efficiency, and mass flow rate of working fluid, are used to evaluate the performance of this recovery cycle. The results reveal that the maximum net power can be obtained for the saturated ORC, when T1/TC is about 0.98～0.99,and the working fluid with higher critical temperature has more net power output. For the supercritical ORC, the higher expander inlet temperature will benefit the net power output, thermal efficiency, and exergy efficiency, as long as the expander inlet pressure isnnot too low. However, the influences of expander inlet pressure on these performance parameters are linked with the expander inlet temperature and working fluids. The capability of doing power output of supercritical ORC is not always better than that of subcritical ORC. Parameters, such as net power, thermal efficiency, and exergy efficiency, and mass flow rate are discontinuous in the process from subcritical conditions to supercritical conditions.

Abstract:An experimental investigation is performed on a single jet issuing into a flow in a pipe. The pressure of the flow in pipe is measured under the condition when there is a right angle between the jet and the mainstream and the velocity of the jet is 1 to 6 times of the mainstream. The results show that, there exists a jet core with skewing downstream near the entrance port; the pressure in that core increases slightly with the fluid incidence. Outside the core, the pressure of the flow inside the pipe increases significantly; the pressure increment is correlated with the velocity of the jet quadratic dependence.

Abstract:The marching cubes (MC) is an effective surface rendering method in three-dimensional visualization for medical image sequence. However, most existing MC algorithms are slow and inefficient because they have to process all the cubes for isosurface extraction. An efficient MC algorithm is proposed by combing the case lookup table and a novel adjacent lookup sub-table to exclude unrelated empty cubes. By explicitly building the fix-length adjacent lookup sub-table that is independent on image sequences, the volumes elements are constrained to those only intersect with the isosurface. Both execution time and temporary storage space are further reduced by incorporating the heap data structure in algorithmic implementation. Experimental results on human head, chest foot CT data sets by using the visualization toolkit package show that the traversal cubes decreases by 95%, and the reconstruction time decreases by 20% without any loss of reconstruction quality. Therefore, the proposed method can remarkably speed up the rendering time and be easily integrated into 3D visualization for clinical application.

Abstract:In order to protect the system of fiber Bragg grating (FBG) and keep its sensing performance on a high score, an adhesive-free bond which is considered as the alternative for epoxy adhesive technology is demanded. An electroless Ni-P plating process without coarsing for fiber Bragg grating was presented. With this plating method, the FBG was coated with a metal clad of Ni-P. By Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD) and Temperature vibration tests, the composition, structure and adhesion force of the plating coatings were analyzed. And the results indicate that the coating is smooth, flat and compact. The solder ability of Ni-P clad was tested by welding the FBG into metal components, and the results reveal that the coating films can meet the requirements of an adhesive-free bond.

Abstract:In order to analyze the influence of construction of new interchange tunnel on existing tunnel, a three-dimension model test of interchange tunnel is carried out with the system of structure and surrounding rockmass of highway tunnel. Existing tunnel’s surrounding rock pressure, internal displacement and supporting internal force are measured. The results show that, firstly, excavating new tunnel has obvious influence on section Ⅰ of existing tunnel, and has little influence on section Ⅱ.All surrounding rock pressure keeps decreasing and arch bottom surrounding rock’s stability reduces. Secondly, crown and hance internal displacement manifest tensile deformation, and the deformation at crown is bigger than that at hance. Thirdly, exiting tunnel’s supporting axial force keeps increasing and supporting moment keeps decreasing. Finally, excavating new interchange tunnel has obvious influence on exiting tunnel’s surrounding rock pressure, internal displacement and supporting internal force when adjacent space is 0.25D, and it indicates that interchange tunnel’s adjacent space should be no less than 0.5D.

Abstract:In order to solve the structural damage identification problem of transmission tower, a two-step identification method based on change rate and dissipation rate of modal strain energy is proposed. The damage location is identified by the change rate of modal strain energy method. Then, the modal strain energy dissipation rate theory is analyzed further by using the element stiffness matrix after injury. As a result, a more accurate damage quantification equation method is introduced. This method requires only several modals of vibration. The numerical simulation results show that this two-step method can find the damage location and damage degree of transmission towers effectively.

Abstract:A new method is proposed for the simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert-Huang transform (OHHT) spectra of its sample observations. Orthogonal EMD method is introduced to treat with IMF. OHHT avoids leakage of energy compared with conventional HHT, and it can be used for analysis of nonstationary signal. The average of the Hilbert spectra over the samples is defined as the Hilbert spectrum of the earthquake motion process and used as the target in the simulation of the process. Random Phase is also introduced to simulate nonstationary earthquake. The statistic characteristics function of stochastic process is given in the paper. Simulations of two earthquake ground motion are carried out. The results show that the samples can accurately reflect amplitude and frequency nonstationary of records. Samples and record of same earthquake ground motion process have same statistic characteristics.

Abstract:In process of the tunnel construction throw New Austrian Tunnelling Method, the result of smoothwall blasting to rock tunnel is not good, there are more and more cavities produced behind the lining. On the basis of engineering project, this paper makes the three-dimensional elastic-plastic analysis throw numerical simulation, discusses the stress-strain behavior of primary support when there is a different size of rectangle cavity behind the lining. In addition the safety factor of tunnel is calculated with cavity based on the strength reduction finit element method. This factor is compared with the factor of health tunnel. The stability of tunnel structure system is estimated through the linear regression analysis between stress of lining and safety factor.

Abstract:A new resident virus propagation model with graded infection rate is established based on the properties of two important stages undergoing by resident virus, which are the latent phase, in which resident virus cannot infect other hosts because it has not yet been loaded into memory and the active phase, in which resident virus resides in memory and infects any suitable program that is executed on the computer. Two computer compartments with different infection rate are established. Furthermore, the dynamic behaviors of this model are investigated by stability theory and numerical simulations. It is found that the dynamical properties of this model are determined by basic reproductive rate. Specifically, virus-free equilibrium is globally asymptotically stable if basic reproductive rate is less than or equal to one , whereas the local asymptotical stability of the viral equilibrium is guaranteed if basic reproductive rate is bigger than one, followed by a conjecture on its global stability. Then the sensitivity analysis of basic reproductive rate to the system parameters is investigated and a collection of policies is advised to control the spread of computer virus over the Internet.

Abstract:The outlier and the measurement that an outlier does not fit the theoretical model in the regression problems are defined. The relationship between the theoretical model and the regression model in the regression problem is analyzed. An approximate theorem is proposed and verified by deleting outlier one by one to construct SVR to approximate the theoretical model. An algorithm of detecting outliers in the SVR problems is constructed based on the approximate theorem. The theoretical analysis of the convergence and effectiveness of the proposed algorithm is given. Then, the step-by-step search algorithm is introduced to improve the outlier removing algorithm to remove outliers in SVR with large-scale samples. The theoretical analysis shows that the improved algorithm is convergent and effective. Finally, the samples produced by two test functions and the samples in UCI data set are used for simulation, and the results show that the proposed algorithm is effective and robust.

Abstract:From human cognition, a face recognition method with local matching based on statistical learning is proposed. The image is divided into several subimages and each subimage is considered as a weak classifier. The Adaboost learning algorithm is used to train the weak classifiers and construct a strong classifier. As a result, all subimages are effectively combined together to explore the best discriminating power and improve the classification accuracy. Compared with the holistic matching methods, the local matching method is robust to variations in illumination, expression, and pose, etc. The experimental results show that the proposed method can improve the face recognition accuracy and is robust to variations in illumination and expression.

Abstract:Aiming at the shortcomings of the existing RSS(received signal strength) based localization algorithm for wireless sensor networks (WSN), a cooperative localization algorithm (CLA) is proposed. A reference anchor node is introduced to tolerant some minor error including the node position error. Dixon detection method is applied to remove abnormal RSS values, while the standard deviation threshold of RSS and learning model are introduced to reduce the RSS ranging error and effectively improve the precision. Simulation experiments are performed to evaluate the performance of the proposed algorithm. The results demonstrate that the localization accuracy is improved effectively, while the stability and robustness are better.

Abstract:Considering the interference introduced by primary user, the outage probability of cognitive relay networks under imperfect channel state information is analyzed based, on the relay selection for the maximum channel gain. In addition, the mathematical optimization model of maximizing the spectrum efficiency under the interference constraint of primary user and the QoS requirement of cognitive user is proposed for cognitive relay networks. Then, the optimal solution of the model is obtained with the Lagrangian method. The proposed scheme improves the spectrum efficiency of cognitive relay networks on the premise of guaranteeing the transmission performance of primary user. Simulation results show that the proposed power allocation scheme improves the system performance compared with the traditional equal power allocation scheme. Meanwhile, it indicates that the approximate spectrum efficiency can be obtained under the perfect channel state and the imperfect channel state. Under the imperfect channel state, the feedback information and the complexity of implementation will be reduced, which is beneficial to the engineering application.

Abstract:According to the perception and adaptive interactive features of information diffusion under the environment of Internet of things,with social physics ideas and vibration propagation concept, the dynamics variables of information diffusion in Internet of things and their corresponding effects on propagation behavior are defined and an information diffusion microscopic dynamics model is constructed based on the damped vibration equation．The Multi-Agent simulation technology and Netlogo simulation platform are employed to simulate the dynamic relationship between the microscopic individual propagation behaviors and the macroscopic overall operation mechanism. The rationality of the model is verified with a large number of numerical simulations．The nonlinear evolution rule of information diffusion system is analyzed based on the simulation results,and the corresponding strategies are proposed.

Abstract:For high precise frequency estimation of the short sinusoid signal at low signal-to-noise ratio (SNR), a weighted fusion algorithm for frequency estimation of the short signal with the same frequency and length (SFL-Signal) is proposed. The spectrum model of SFL-Signal and the phase compensation matrix with phase coherent and noise cancellation are constructed. Secondly, the SFL-signal spectrum is weight-fused with the phase compensation matrix to obtain the result almost the same as that of the spectrum of the phase-coherent sinusoid signal. Consequently, high frequency estimation precision is obtained with spectral peak searching of the weight-fusion spectrum. Algorithm analysis and simulation results show that, compared with the existing methods,the proposed algorithm works better in term of precision, calculation complexity, noise immunity, and fits for any type of SFL-Signal.