Advanced Materials Research Vols. 546-547

Abstract: In this paper, the embedded control system of mobile robot was designed by using the LPC2114 as processor, the function hardware module block diagrams were provided, and analyzed the algorithm of testing speed part of system and motor drive part; the system with the high precision sonic sensor module can avoid the obstacles, which can enhance the security performance of system, the modules for wireless communication and friendly human-machine interfaces make convenient for the use of customers and the developing and debugging of the system.

Abstract: A space vector pulse-width modulation (SVPWM) strategy was developed to solve the failure of traditional SVPWM. A two-phase modulation method is adopted basing on the analyses of traditional SVPWM to select the null switching state in each sector according to the power factor angle. As a result, when the current is crossing zero, the corresponding phase does not commute and dead-time compensation is avoided; and when the current is nearing the peak, the corresponding phase also don’t commute, which leads to lower switching losses. The simulation and experimental results validate that the proposed strategy can effectively improve the current wave, minimize the current distortion and reduce the switching losses. Furthermore, the algorithm is easy to implement.

Abstract: A fast algorithm for estimating the control horizon of the input constrained linear quadratic regulation (LQR) problem is presented. It is known that there exists a finite horizon such that the infinite horizon constrained LQR problem can be solved as a finite horizon constrained LQR problem. An efficient algorithm to estimate the upper bound of the horizon is presented based on the linear programming. It only needs to solve a linear programming problem for on line application. Finally, the comparison among some methods is shown by an example. The proposed algorithm has less conservative than those of other algorithms.

Abstract: The article introduces a certificateless signcryption scheme targeting the problem of lacking of security mechanism in the routing of satellite networks, and designs a secure routing protocol suitable for the satellite networks. The proposed protocol avoids complicated management in the certificate mechanism and bypasses the key escrow problem in the identity-based cryptography using the certificateless cryptography and signcryption. The analysis shows that the new protocol can resist several common attacks, effectively improve the security of the satellite networks routing.

Abstract: The study object is traffic flow on main road of urban traffic networks, the traffic condition is recognized by traffic flow theory and fuzzy logic method. The average space speed is a variable of the fact flow function, the road congestion degree is described by the ratio of fact flow and traffic capacity; the ratio of congestion time length and total time length is the congestion frequency. Considering congestion degree and congestion frequency, a fuzzy logic method is used to describe the traffic state by three grades: free, congestion and serious congestion. At last, the numerical example is given to analyze traffic state.

Abstract: Currently, Email is one of the most popular applications in people’s life. A secure email requires that the email system can provide encryption and digital signature, PGP is a popular email encryption and transmission method, the paper gives a brief overview of email security, details the PGP algorithm, function, encryption and decryption process and public/private key pair generation process, and analysis’s Security of PGP.

Abstract: Defined the parameters of forest landscape according to the characteristic of forest landscape pattern combined with complex networks theory. By using landscape blocks as nodes, the affect between plaques as lines, a coupling network modeling of forest landscape plaques is established. Taking the west Tongting Lake in Hunan province as the study area, divided the landscape pattern into 13 types, established a plaques coupling network by using the patch edge effects between two different type of blocks as power of lines. It shows that the degree of node, the indexes of landscape classification has positive relationship with the power of node, the degree of node has positive relationship with the importance of node, the area of landscape has complicated competition with the landscape fragmentation when contributes to the concentration degree.

Abstract: In view of the actual application of the status quo of the current digital campus universities, a unified campus authentication systems and solutions for the overall framework was proposed based on the introduction of Kerberos technology and LDAP protocol, in order to improve the utilization and security of campus resources.

Abstract: In this paper, the system engineering theory research logistical equipment safeguard ability assessment method, and established the equipment support of the evaluation index system, using BP neural network can to approximate any nonlinear system advantage, based on the BP neural network of logistics equipment support capability evaluation model for logistics equipment safeguard the ability to provide a new method. The simulation results show that this method can ensure objectivity.

Abstract: More and more people are using mobile equipments to access business resources from the organization's internal network, how to ensure the data security in the data transport process of mobile intelligent terminals is becoming an urgent need to address issues. This paper proposes a new solution of mobile VPN which using the SSL to protect the data flow and SOCKS5 proxy technology to redirect flow, and gives the analysis of its performance improvement principles.