To ensure the security of VoIP (Voice over Internet Protocol) system, a comparatively systematic discussion is made to security issues found in the development and widespread application of Internet based IP(Internet Protocol) phone. On the basis of analyzing existing security threats, relevant security suggestions are offered to security issues which may crop up at any time when a company deploys its VoIP.

PDS(Pattern time Delay Shift coding) scheme can decrease the aberrance of the signal caused by the channel multipath effectively, and RS code has the superiority combining with the PDS scheme congenitally. Integrating RS code with PDS scheme is achieved, and the performance of selected RS code utilized in underwater acoustic pattern time delay shift coding communication system is discussed. The performance of RS code and Convolution code used in PDS system is compared. The simulation results showthat the performance of RS code is much better than convolution code in PDS system. Lake trial results prove its superiority.

An amelioration algorithm to the FH(Frequency-Hopping) signals parameter estimation,United Algorithm basted on  STFT(Short-Time Fourier Transform) and WVD（Wigner-Ville Distribution), was proposed to solve the problems of failing timefrequency resolution and oversize operation quantity, which occur in FH signals parameter estimation with smoothed Pseudo WVD (SPWVD). STFT-WVD could achieve FH signals parameters blind estimation successfully, which include hopduration,hoptiming and hopfrequency. In parameter estimation, STFT-WVD suppresses the crossterm interference in WVD effectively, and keeps the excellent timefrequency resolution as WVD. The operation quantity is almost equivalent between STFT-WVD and WVD,the STFT-WVD does not increase the complexity degree of the operation. Finally, the simulation result proves that the holistic performance of STFT-WVD is better than SPWVD, and STFT-WVD can get more precise parameter estimated values while SNR exceeds－1 dB.

To improve the efficiency of working and monitoring.A method of using Microsoft ole automation interface for integrated re-development of the MS project is proposed and the Microsoft Project task attribute and the resources attribute are introduced. It has realized system finally, which bases on the OLE(Object Linking and Embedding) interface to automate Microsoft Project, carried out data exchange between the project and the application procedure well, achieved the seamless connection finally, and given the general solution for the Microsoft Project re-development.

In practical applications, we always need to resolve a series SAT(Satisfiability Problem) problems which only differ in a few clauses between corresponding CNF(Conjunctive Normal Form) formulas. However, most of current SAT solving algorithms are designed for single SAT problem.An algorithm is proposed which is based on DPLL and can solve a set of SAT problems at a time. Tests on random problems demonstrated that: nDPLL algorithm reflects high efficiency on some CNF formulas; the efficiency of nDPLL is  proportional to the size of CNF formulas, close factor and the ratio between the number of clauses and variables.

The car multimedia systems generally use a traditional connection with the transmission, there is no uniform standard wiring harness and it is difficult to expand. In the study of MOST (Media Oriented Systems Transport) for multimedia transport protocol, based on the combination of MOST NetServices using ATmega128 provides the basic functions of the design and implementation of the MOST fiber-optic network DVD (Digital Versatile Disc) playback node hardware and software, and connect to the MOST fiber optic network, to achieve with the audio node, master node to control the transmission of information and multimedia information. The experimental test, based on the MOST network, multimedia messaging, voice received smooth, clear sound, no noise, smooth video playback.

The concept of network dynamic topology is proposed, for a variety of pre-integrated presentation of the network to the ceremony; make positive and negative sequence training methods, and gives proof of uniqueness of solution, avoiding each training sample must be randomly generated sequence of problems, the network connection right to randomly generated initialization is no longer needed. Regression analysis of artificial neural networks an effective solution to two stochastic processes on the training result, the adverse effects on the stability and credibility of the application of artificial neural networks provides a theoretical basis and technical support.

In rezpanse to the single formation control of mobile robots and the problem of local minimum, this paper provides an improvement of artificial coordinating field, during which the formation varies from time to time and the amounts of robots, achieving the traveling formation and the traveling target point is suitable to be chased, making robots ability of avoiding obstacles more flexible.And the method is verified through simulation experiment.

Summary for development of visual navigation methods would benefit the further exploration in this field.  The classifications of visual navigation methods were discussed. And the representative articles were introduced under the classification of mapbased visual navigations, mapbuilding navigations and mapless navigations. Then a review of integrated navigations with vision was presented. Analysis of recent works on the visual navigation showed that the hotspot of visual navigation had extended to intelligence and multi-sensor fusion.

In order to solve the communication problems between bus networks of a vehicle, a basic prototype of CAN(Controller Area Network) gateway is designed and implemented based on vehicle CAN network. The gateway prototype is used to connect five subsystem networks of car body, satisfying internal communication within subnet and achieving exchanging data between sub-networks accurately.The vehicle network data traffic is effectively reduced. The error control, flow control and other basic functions of vehicle networks are realized by combining the characteristics of CAN bus. Our work practically improves achieving the network system on vehicles.

In order to discuss the changeable weight combination forecasting model and its application in landslide forecasting, the study based on the date of actual monitoring of Xintan landslide in A3 part in Zigui country,Hubei province, and using the changeable weight combination forecasting method which based on grey model,Verhulst model and cooperative model to simulate and forecast the part of monitoring point displacement of Xintan landslide. The results indicated that the changeable weight combination forecasting method was more precise than one single forecasting method, maximum difference of error sum squares is 10408 and minimum difference is 0184. So this method can be applied into the engineering practice.

In order to better understand the impact of information industry on the growth of economy, the development scale and degree of information industry should be quantified, the technology of data mining in the information industry measure is applied and a comprehensive level method of information industry based on selforganizing data mining is designed,and it will have a comprehensive measure to the information industry, analyzing primary factor of influence on information industries. The results show that, this method overcomes subjectivity of the information industry measure, it overcomes the deficiencies of single measurement method of information industry, increases the accuracy of results, suits the inputoutput relations  complex the economic problem (nonlinear problem) appraisal.

To solve the traditional limitations of personalized search engine, afterstudying user s interest search engine present situation, through multi\|agent more comprehensive record, analysing user search  behavior, a new comprehensive user search behavior is proposed, the construction users interest search engine research frameanalysis based on multiagent user search behavior model of user interest. The results show that, based on user search behavior to construction user interest model will enable the search engine returns results closer to user needs, satisfies the user personalization service, thus enhancing the information search recall and the accuracy ratio. 

In order to research the application of new computer technology in teaching, and enhance the teaching quality, we represent the designing of a viedo conference system based on the techniques of FLV（Flash Viedo） streaming media combined with Flex RIA（Rich Internet Applications）, Spring2 and Cairngorm microarchitecture. It has been used successfully in application. 

To address distortion problems of auto parts during the fatigue test.According to the experimental data, the mathematical modeling is made. Based on the actual requirements an appropriate performance indicators is constructed and the use of the optimal control algorithm be realized system output to track the amplitude of the input optimal control law. Through the Matlab numerical simulation and real-time simulation of the optimal control algorithm.

For enhancing flexibility of data access to resolve heavyweight server problems, using factory patterns,the singleton patterns are applied to design NET platform general database access layer with ADONET (ADO：ActiveX Data Object) technology, and the core code are given. The technology of design patterns to the project design can reduce the load on the system server, and makes the data access layer more flexible, and improves system of portability and scalability. In the education management system application, data access based on design patterns improves the stability of system, uses server resources, increases user satisfaction, and is theoretical basis for the future program development.

In order to solve the problem of audio digital products ' copyright protection under the network environment,a new algorithm for digital audio watermarking based on the DWT(Discrete Wavelet Transform) is put forward. The algorithm uses the sum Binary value of the neighboring three watermark bit combination to locate the embedding position,and make its value smaller. The watermarking picture being embedded into audio signal also ensures the ability of attack resisting and adaptation, which could be used to protect the copyright of digital audio signals. The merit of the algorithm is that it takes advantage of the speediness and simplicity of the DWT. Arnold transformation guarantees the security of watermark image.The simulation experiment on the MATLAB is carried based on the algorithm and the results demonstrate robustness and imperceptivity of the algorithm.

By presebting the whole process for the 2-factorization of the odd order complete graph K₁₃, we discussed the detailed steps for 2-factorization of the odd order complete graph K_2n+1, and finally solved the 2-factorization problems of the complete graph.