Using the test function method and the upper-down solution method,the existence of the critical exponent of blow up for a non-local reaction-diffusion equations which comes from combustion theory is studied.It is shown that the critical exponent of blow up belongs to the blow up case.
In order to solving the problems caused by more and more complexity authorization in digital campus,three mainstream control technologies are analyzed and a new method to implement RBAC is proposed.Authorization management system takes J2EE as framework,uses XML to express access control rules.The rules control data in rows,cols and time is abstracted,which satisfies the flexible requirements in digital campus application systems.
To improve the differential algorithm,a new kind of heuristic optimization method and a modified differential evolution(MDE)scheme are presented,where DE/rand/1/exp and DE/best/1/exp run currently in evolution process.With the usage of current aggregation degree,the search range of re-initialization of the MDE is reduced and the randomicity of re-initialization is avoided efficiently.The experimental results show that the search ability of MDE is improved remarkably compared to DE with single differential strategy and PSO.
A class of mutli-point boundary value problem with p-Laplacian operator is studied.By integrating on both sides of the equation,its equivalent integral equation is obtained.Using the fixed point theorem on cone,it is shown that the integral equation has positive solutions.The existence of one or more positive solutions of mutli-point boundary value problem with p-Laplacian is proved.
In order to improve the solving efficiency and accuracy of each composition ring deviation in the process dimension chain,the equal-precise computing criterion is adopted.An algorithm for tolerance and fitting of the dimension chain is presented with VC++.Test examples show that the proposed algorithm runs well,and the standardization for computing the composition ring deviation is completed.
Research on the architecture,communication mechanism and Schedule mechanism of TinyOS in Wireless Sensor Networks.According to the shortages of Scheduler,an improved round-robin scheduling strategy based on deadline is proposed,and it is validated on the micaZ platform.The result of simulation demonstrates that the improved schedule strategy can increase the throughput of communication and improve the communication performance.
Based on the Preisach model,hysteresis is included in the numerical simulation of an electromechanical control system.Some techniques,such as unidimensional storage and nonuniform griding are used to improve the solving efficiency,and suitable sampling is recommended to overcome the iteration difficulty.The proposed numerical method is applied to a rigid rotating disk suspended magnetically,which is controlled by a PID regulator.The simulations of floating-up process and unbalance cancellation show that while considering the effect of hysteresis,the simulation can still be implemented successfully,which hints a more effective method of designing magnetic suspension systems for rotors.
In Ad Hoc networks,the operation of Dual Busy Tone Multiple Access(DBTMA) solves the hidden and the exposed-terminal problems,but it causes the fairness problem at which some modification has been proposed aimed.In improved DBTMA,the transmit busy tone is got rid of and the RTS packet is transmitted in slotted ALOHA scheme,which improves the probability of successful RTS reception.The result of simulation shows that improved DBTMA scheme decreases the complexity of the protocol,reduces the transmission delay,and guarantees the fairness of system and the steady performance.
The application of the Data Warehouse(DW)technology in financial information management is discussed.The system structure of Financial Information Manage System(FIMS)and the design of financial data module are described in detail.It is helpful for financial organizations to do better than others in drastic competition by using the proposed system.
Regard to the edge detection of QFP chip image in vision detection of SMT equipment,a threshold determinated method by gray histogram is brought forward to segment QFP image.By image processing steps of segmentation → filter → edge detecting,the pins of QFP chip are taken from QFP image completely.The experiment results show that this method gives well edge and can satisfy high speed and high precision vision detection in SMT.
According to the ball mill noise formation mechanism,the state of arts for the present domestic and foreign controls ball mill noise technology is given.The paper focus on the ball mill lining structure and the noise reduction effect influence to the material quality.Each kind of new noise reduction material noise reduction effect are described,and the passive noise control technology is one kind of effective control technology.It is the ball mill noise control development direction to exploit high performance noise reduction material by controlling the noise and vibration source.
Introducing the design method of the tubular ozone with narrow discharge air gap and glass dielectrics.By analyzing the ozone cell electrical characteristic,theoritic resistance to voltage,and the ingredients which affect the character of ozone cell,it can be concluded from the result of the experiment and academic analysis that one tubular ozone cell of glass dielectrics will produce ozone more than 100 g / h in expect if only we choose optimized configuration parameter and work condition.
Variable structure control of electromagnetic vibrator is studied.Through the establishment of nonlinear mathematical model,it uses variable structure control to control the electromagnetic vibrator.This method can overcome the shortcomings of traditional PID control that are lack of adaptability and parameters of the controller requiring constant adjustment.The simulation results show that,variable structure control algorithm can reach the purpose of the precise control with the system parameters change or outside interference and this system is more robust.
In order to decode accurately in receiver of digital communication system,timing pulse for bit is needed.Extracting method for timing pulse by DPLL is discussed.A realization scheme for DPLL composed of differential pull aheadlag phase detector is proposed.The Verilog-HDL program based on FPGA is introduced in detail and the simulation waveform is given.Finally,an example of applying in CMI decoder is demonstrated,The DPLL is tested and it works credibly.
为了能在数字通信系统的接收端对信息进行正确译码,需产生一个用作取样判决的位定时脉冲.对采用数字锁相环提取定时脉冲的方法进行分析,提出了一种由微分超前/滞后型鉴相器构成数字锁相环的Verilog-HDL建模方案和基于FPGA实现该方案的设计过程,给出了仿真结果.以锁相环在CMI线路码译码中的应用为例,验证了该锁相环工作的可靠性.
To overcome the instability after tire blowout,a new method of emergency inflation is proposed.The gas generator is to be triggered urgently after tire blowout to inflate the spare inner tube.With a typical vehicle vibration model of two degrees of freedom,a simulation model for emergency inflation after tire burst is built using Matlab/Simulink software.The results show that the emergency inflation technology can improve the rideability effectively.
In order to collect competition information automatically,reducing errors caused by manual operation,a wireless marking system is designed based on the embedded WinCE operation system and the Intel PXA255 hardware platform.The designed system can eliminate errors caused by manual and increase the efficiency of information processing.Test results indicate that the system can collect competition information timely and correctly.
The 1 kg / h ozone generator′s cooling system is analyzed.The ozone concentration and power consumption be influenced by the cooling conditions are discussed.We get some relation graphs among the zone concentration and power consumption and the cooling conditions.Tests results show that the excess air temperature,cooling water temperature and cooling oil temperature are very important for ozone output,and power consumption.
The Bootstrap and logistic regression are combined to solve the credibility problem arising from the small samples in biostatistics.First,the Logistic regression model is applied to a categorical data set in biostatistics to get the parameter estimations and hypothesis tests.Then the Bootstrap is applied to get the new hypothesis tests in both the model and the parameter estimations.The test example shows that the outcomes from the Bootstrap method can help us to make a decision for the ones from the logistic regression model.
A remote design system for machining parts is designed on UG platform using VC++,and the developed programme is encapsulated into a COM component.Based on ASP,the remote parameterized design for machining parts is implemented.An example for designing the gear is given to show the remote design process for the machining part.
