Applied Mechanics and Materials Vols. 347-350

Abstract: As the forefront of mobile communications, mobile phone industry broad market prospect attracts more and more enterprises to enter this field. With the rapid improvement of the industry, mobiles develop from original feature phone to smart phones, which can take pictures, catch video, access Internet and so on. Meanwhile, performance of camera also becomes the focus of peoples attention. This paper analyzes the performance of the camera objective and subjective evaluation methods, and raises the appropriate test standards. Finally, it suggests a comprehensive evaluation of subjective and objective scoring method, hope can be promoted.

Abstract: The small signal modeling technique based on the generalized state space averaging method is applied to single phase full-bridge resonant DC/DC converter .According to the simulation, the frequency characteristic curve is obtained from MATLAB, this paper analyzes the influence of the duty ratio, input voltage to frequency characteristics, then builds a closed loop simulation circuit with PSIM software, the simulation results show that, the small signal model has good controllability and anti disturbance resistance, generalized state space averaging method is more accurate to series resonant converter modeling.

Abstract: This paper presents an improved multistage variable-step incremental conductance method to achieve the maximum power point tracking (MPPT). Compared with the traditional variable-step incremental conductance method, this improved algorithm optimizes the selection of the step size so that the tracking of the maximum power point is more quickly and the steady-state performance is better. Furthermore, the algorithm can still guarantee the quickness and accuracy of MPPT when the environmental conditions change suddenly and tremendously. At last, matlab simulation was applied to compare the characteristics of multistage variable-step algorithm with that of the other. And the simulation results verified that the improved algorithm has better dynamic and steady-state performance.

Abstract: Regarding the AC UPS fault accident happened in one compressor station which caused severe consequence with gas transmission pipeline, this paper lists the possible reasons based on the recorded fault code and equipment configuration, and solutions are proposed for modification. In the end, recommendations are given for the future project design of AC UPS.

Abstract: USB disk and UKEY are common applications of USB Mass Storage and CCID protocol and used widely in our daily life, but they are always deployed on different kinds of devices such as USB disk and UKEY. A potential application that integrates the functions of these two protocols into one device is discovered by us. In this way, we can regard a single device as a mass storage and an UKEY as well. According to this discovery, a new Mass Storage and CCID composite device is developed on IS8U192A development board. After this, several tests are made with some test tools to ensure the newly developed device is able to function well and the Mass Storage and CCID protocols are accurately implemented.

Abstract: This article analyzes the accidents of power grid in some domestic region to discuss the security problems existing in the power grid Energy Management Systems (EMS). Combined with the security requirements of EMS, the method of improving EMS security based on SOA is proposed and the involving key technologies are studied as follows: the loosely coupled EMS based on SOA, the graded and modularity security configuration, the management of security configuration based on Concurrent Version System (CVS) and the mirror of Real-Time Databases (RTD) based on cloud computing. All the above technologies proposed in this paper greatly improve the security of EMS.

Abstract: This paper presents Extended Kalman-filter (EKF) algorithm which is based on a first-order Lithium-ion batteries model. Curve fitting According to the OCV(open circuit voltage),SOC(state of charge) parameters measured in experiments, descript status equation and observation equation of Lithium-ion battery in detail , so that it can accurately demonstrates the characteristics of the Lithium-ion battery. Simulation and experiment results show the feasibility and effectiveness of the algorithm.

Abstract: Performance of coherent atmospheric optical communication system with heterodyne detection and LDPC codes was evaluated over atmospheric channel attenuations of which are about 20-30 dB/km. To reduce bit error and enhance the system performance LDPC code was implemented in system. Combining coherent detection and LDPC codes could reduce the received power requirement ~4 dBm at the BER of 10^-9.

Abstract: As the development of technology, the wireless sensor networks (WSN) have a wide spread usage. And people pay more attention on the localization algorithm, as the key technology of WSN, there have been many method of self-localization. The concentric anchor-beacons (CAB) location algorithm is one of the most practical one, which is a range-free WSN localization algorithm. In order to further improve the accuracy of localizing nodes, an improved CAB location algorithm base on Received Signal Strength Indicator (RSSI) is proposed. The RSSI is used to measure the distance between two anchors and compare with the practical distance. Then the environment between two anchors can be simulated. At last the communication radius of anchors can be optimized. And the common area of the anchors in the process of localizing nodes can be reduced. Then the accuracy is improved. By simulation, the localization accuracy is improved when the anchors numbers is more than a certain percentage.

Abstract: Low Density Parity Check code is more and more taken seriously in high-speed transmission. In this article we represent a LDPC coder and decoder which based on IEEE802.16e and realize the coder and decoder with Virtex-5 FPGA. By using Matlab to make an off-line system simulation, we analyzed and compared the LDPC performance under the different length of code for LDPC coder then analyzed the influence of different iteration to the LDPC BER performance of decoder.