Applied Mechanics and Materials Vols. 40-41

Abstract: A front end frequency measuring system with a CPLD and an embedded system as the core circuit is designed to achieve the automated connection and measurement of multiple sensors. Then, according to practical project condition, a data transmission scheme with the integration of wireless and wired communications as well as the combination of a private network and a public network is selected. Data transmission from measuring nodes on the top of the shaft to the bottom is completed by wireless data transmission modules, data transmission from measuring nodes at the bottom of the shaft to relay nodes in the main tunnel is completed through a RS485 bus, and data transmission from relay nodes in the main tunnel to the office is completed through the GSM network, thus the remote health status monitoring of civil engineering projects is achieved.

Abstract: Applying GW model simple exponential probability density to approximate the Gaussian one is not explicit for some cases. Some practical closed form analytic solutions were derived for the contact load, contact area and contact spot number for both GW elastic contact model and CEB elastic-plastic contact model by the generalized exponential probability density fitting the Gaussian one.

Abstract: The status of internet development in China, the current problems in broadband access technology, and the comparisons of next-generation access technologies of Asymmetric Digital Subscriber Line 2+ (ADSL2+) and fiber to the home (FTTH) are presented in this paper. It is proposed that the development of FTTH is of great importance in the future internet. Moreover, the current problems of FTTH cost and development prospects are also analyzed.

Abstract: In this paper, a new ultrahigh frequency circularly polarized microstrip antenna using in RFID reader is proposed. The proposed antenna has a simple structure, it has non-symmetrical rectangular corner truncated square patch, ground plane and a probe feed. To achieve good circular polarization(CP) radiation characteristics, it uses air as the dielectric layer. Simulation results of a constructed prototype with the center operating frequency at 923 MHz showed that the antenna has a return loss S11 of about −24 dB, a gain level of about 9.48 dBi. The antenna has good impedance and radiation characteristics over the required bandwidth, 920-925 MHz (Chinese UHF RFID band).

Abstract: An unmanned mining technology for the fully mechanized longwall face automation production is proposed and studied. The essential technology will bring the longwall face production into visualization through the Virtual Reality (VR) and Augmented Reality (AR) union. Based on the visual theoretical model of the longwall face, the combination of virtual and reality, the real-time interactive and the 3D registration function were realized. The Key technology and Alpha channel are used to the combination of the real long wall face and the virtual user.

Abstract: This paper aim To analyze and discuss a Query-based Routing Method in P2P network (QRM) , In this algorithm,the node records the received query and the nodes that can answer the query very well,in these nodes, Simulation experiments demonstrate that the method can enhance the searching efficiency very well with the number of queries becoming more and more.

Abstract: In this paper, the analytic hierarchy theory and fuzzy mathematics method from ergonomics perspective were used to research reliability of the electrical safety evaluation system from coal mining enterprises. In view of ambiguity and randomness of the evaluation system, the multi-level electrical hazard evaluation system was established and the objective weights were calculated on expert consultation method. Finally, the evaluation procedure and evaluation model from a large coal mining enterprises was given. The experimental results show that the evaluation system has a certain engineering value.

Abstract: According to the requirements of wind farms real-time supervisory information system, a WebGIS with Browser/Server (B/S) architechture is developed based on MapGuide to implement wind farms supervisory information system. It has the functions such as map browse, roaming,.dynamic appending data, real-time display and so on, thus achieving 0-4 hours super-short-term accurate prediction of wind power.

Abstract: Since the usable range of the frequency spectrum is limited, the frequency assignment problem (FAP) is important in mobile telephone communication. In this paper, according to the characteristics of engineering- oriented FAP, an engineering-oriented hybrid genetic algorithm (EHGA) based on traditional genetic algorithm (TGA) is proposed, combined with particle swarm optimization (PSO) and simulated annealing (SA). The results obtained by the simulation to a real-word FAP case in GSM show that the algorithm we proposed is a better approach to solve the engineering-oriented FAP.

Abstract: An ad hoc network is a dynamically wireless mobile network. It can construct network automatically and quickly. Because of the importance and universality of application, ad hoc network is trend to become a research hotspot. It is necessary to research an effective routing protocol so as to be adapted to mobility of terminal equipment and to provide the reliable data transmission. This paper firstly studied and analyzed existed routing protocols, and simulated these protocols. Finally we proposed an improved routing protocol based on DSR and AODV, in which we divided all nodes into different clusters, and every cluster has only one cluster head. These nodes within the same cluster communicate using DSR protocol while those nodes in the different cluster communicate through the cluster head using AODV protocol. So, the data packet can go through the shortest link, thus it can decrease transmission delay and reduce energy consumption remarkably. Finally we use the network simulation software named NS2 to simulate experiment result. The results show that this protocol can improve the performance and the service quality of the network.