Applied Mechanics and Materials Vols. 380-384

Abstract: Equipment maintenance support system is important for raising maintenance support efficiency. On the analysis foundation of equipment maintenance support demand, this paper carrys out function design for maintenance support system. SOA and Web Service based realize technical systematic Architecture is put forward. Then how to adopt Web Service and J2EE have been analysed briefly. Finally, actual problems in application course that may be met are discussed and the further research direction is showed.

Abstract: Concurrent Multi-path Transfer extension of the Stream Control Transport Protocol (CMT-SCTP) has great potential to improve the utilization of scarce network bandwidth resource. Traditional CMT-SCTP adopts Round Robin (RR) algorithms to carry out packet scheduling that could affect the performance of SCTP traffic as unordered issues. In this paper, we discuss the unordered issues and propose a novel packet scheduling algorithm to improve the performance in heterogeneous wireless network. Our main idea is predicting the packet arriving time and then provides a path selection strategy. Through measuring round-trip time (RTT) and available bandwidth, we achieve an algorithm to predict the arriving time of data packets on one path, then give a reasonable path selection strategy to make sure that data arrives in the right order. By using proposed algorithm, the unordered packets and receive buffer blocking are reduced. We evaluate the performance of our algorithm by comparing it with the RR algorithm and show that it can resolve several performance issues.

Abstract: In recent years, the ZigBee network has been rapid develop in smart home. In order to solve the intercommunication barrier in heterogeneous wireless networks in the smart home, a wireless home gateway which is based on embedded is designed and implemented in this paper. The gateway is made up of the main controller S3C2440, the ZigBee module JN5148 and the Wi-Fi module VT6656. It is capable of converting Wi-Fi protocol data or ZigBee protocol data, transmitting them to each other and integration of heterogeneous wireless networks. This paper describes the design and implementation process of the gateway hardware and software, introduces the Wi-Fi protocol data and the ZigBee protocol data conversion approach, and resolve the bottleneck caused by the two protocol different transmission rates. Then the performance of the gateway is tested, and the results indicate the Wi-FiZigBee gateway is completely meeting the needs of the smart home.

Abstract: Equivalent induction motors with equivalent static loads are applied in load models. However, load appliances are installed on low voltage buses in power grid and the distribution network impedances cannot be neglected. A synthesis load model considering the distribution network can describe the load structure more completely and precisely. A comparison including the composite load model simulated powers and the synthesis load model simulated powers with the measures are described in this paper.

Abstract: In the wireless access technology system, reliable and more efficient security algorithm is important to guarantee high-speed data transmission of LTE. In the development process of LTE-A Radio Frequency Conformance Test System, we designed a detailed security process in PDCP ( Packet Data Convergence Protocol ) and realized it through encryption algorithm and Integrity algorithm. This paper adopts SDL and TTCN to test the security process of PDCP.And we applied it to LTE-A system successfully.

Abstract: A novel parallel control strategy based on the CMAC controller and PID control is proposed which is to solve the problem of extraneous torque which exists in the load simulator. In which, the CMAC controller realizes feed forward control, yet conventional PID controller only realizes feedback control, and using the PD algorithm improves system. The simulation results show that output of the conventional PID controller completes unceasing on-line learning by the CMAC neural network. Effectively suppress the extra torque of the load simulator, the Load Simulator system performance has been improved significantly.

Abstract: With the popularization and development of computer network, people's life and work more and more relies on the network. However, many people can cause network security problems due to improper use. Therefore, based on the primary analysis of the current computer network security status, this paper proposes how to make the system strengthen, safety and how to carry out safety inspection after being attacked, in order to ensure the security of network.

Abstract: In the wireless sensor network routing protocol design, the sensor node monitoring data in multi-hop relay approach to sink node for transmission. For sink aggregation node fixed network, the nearby sink nodes of sensor nodes need to transfer other nodes of the monitoring data, consequently, it consumes large amounts of energy, and it's easy to premature death, making the network connectivity decline, even making the network intersected, shorten the lifetime of the network. In order to solve this problem, from the view of sink node, this thesis brings forward a protocol of SERP, which is a energy balancing routing protocol based on sink Mobility and prolongs the lifetime of network. It adopts the strategy of sink movement which makes the hot nodes inside the network take turns, balances the load among them. In SERP, firstly, the WSN deployment area is divided into finite Virtual cells ;Secondly ,we make the center of each virtual cell as the mobile position of sink node; at last, we confirm the residence time when sink node stays in each position through linear programming. Finally, the paper makes simulation al analysis aiming at above-mentioned routing protocols . The result shows that the inside node energy consumption is comparatively balanced and efficient, and the network lifetime is prolonged effectively.

Abstract: As a new community model, virtual learning community has become a kind of brand-new exchange and knowledge sharing model in the Internet era. Based on the analysis of the information concepts of virtual learning community, summarize the elements of virtual learning community, puts forward the corresponding construction step, summarizes the construction characteristics and tasks of various stages, and points out the future development prospects.

Abstract: With the purpose of acquiring the Web system to work correctly under the guidance of software requirement, load testing is one of the important approaches. In this paper a web load testing based on performance target is proposed. Then several key points of achieving the load testing based on LoadRunner are discussed. At last combining a case study about the information management system software, Web load testing automation is achieved and testing results are analyzed.