Applied Mechanics and Materials Vols. 701-702

Abstract: PoC is a half-duplex PTT service using VoIP technology based on cellular network packet domain carrying. However PoC uses the standard Session Initiation Protocol (SIP) to setup session. The standard SIP signaling is too long, which brings more setup delay and does not hold true the wireless communication network, so it must be cut. This paper researchs the method to reduce PoC session setup delay from SIP session cut. We achieve the testing results in the actual commercial network. The results shows that this method can effectivly shorten the PoC session setup delay.

Abstract: Objectives: Solve the security problems on information transmission between different debarments in hospital management network system. Methods: Put forward a security transmission mechanism based on ECC and AES algorithm which using the hybrid encryption scheme combined with ECC and AES algorithm to ensure the safety of the information transmission process, using the ECC signature algorithm to achieve the identity authentication between different functional departments, using the hash function to realize the integrity authentication of information. Results: This mechanism has been implemented by Java programming and it could effectively ensure the security of information transmission which has been proved by practice. Conclusions: The algorithm of this security Mechanism has been implemented by using java language. Experimental results show that it is effective to keep the security of information transmission..

Abstract: Mobile information service is one of the development direction of library information service, WeChat as an instant messaging products, has attracted the attention of all sectors from the beginning. The first analysis the current situation of mobile information service of library, points out existing problems; then introduce WeChat and WeChat public account, describes how to realize the function that the use query library information through the WeChat with the help of WeChat public platform as a carrier. And analyze the realization method of setting WeChat public platform, building interface server, certificating in the docking process and querying data in the background.

Abstract: Trojan detection plays an important role in the discovery and treatment of Trojans. Acquisition and analysis of memory mirroring is a new research topic of computer live forensics. Computer forensics often need Trojan detection to determine whether target machine has been controlled. This paper proposed a Trojan detection method based on computer live forensics. Construct probabilistic fuzzy cognitive map(PFCM) through analysis of memory mirroring, use memory mirroring Trojan detection algorithm, calculate the probability of the existence of Trojan. The results showed that this method can effectively determine whether there were Trojan in memory mirroring. Detect Trojans through the analysis of various aspects of memory and numerical computation, proposed method improve the accuracy and reliability of Trojan detection.

Abstract: In order to solve the security problem of data’s exchange and sharing among every information island, as well as between power enterprises and power customers, we propose data security exchange of user behavior trusted: recording the data’s essential attribute and user operation in clients; data transmission can be achieved by unified security exchange protocol; servers filter data according to data’s essential attribute, user operation and configure policy, by association analysis of customers’ abnormal behavior, and check user behavior trusted. By means of analysis, data exchange of user behavior trusted can ensure data’s security exchange from data transmission, data security and user behavior trusted three aspects in heterogeneous environment.

Abstract: Clustering the sensor nodes and choosing the way for routing the data are two key elements that would affect the performance of a wireless sensor network (WSN). In this paper, a novel clustering method is proposed and a simple two-hop routing model is adopted for optimizing the network layer of the WSN. New protocol is characterized by simplicity and efficiency (SE). During the clustering stage, no information needs to be shared among the nodes and the position information is not required. Through adjustment of two parameters in SE, the network on any scale (varies from the area and the number of nodes) could obtain decent performance. This work also puts forward a new standard for the evaluation of the network performance—the uniformity of the nodes' death—which is a complement to merely taking the system lifetime into consideration. The combination of these two aspects provides a more comprehensive guideline for designing the clustering or routing protocols in WSN.

Abstract: In this paper, a semi-blind estimator based on orthogonal superimposed training (OST) for the case of doubly selecting fading channel is proposed. With the aid of OST, the interference to channel estimation form data symbols can be eliminated completely. Moreover, data symbols can serve as pseudo-pilots to enhance the estimation performance. Simulation results illustrate the benefits of pseudo-pilots method.

Abstract: This paper presents a scheme of information transmission system for undersea observation platform based on all-optical network. Through flexible using of WDM, OADM, EDFA, RFA, DCF and other technology, it effectively compensates chromatic dispersion, restrains nonlinear effects and noise problems. Fibers in primary nodes are directly assigned to ensure mutual independence between different transmission links. Dual-fiber bidirectional transmission mode that wavelength of one fiber drops to the node by OADM, then return to the same transmission station in the other fiber, increases the reliability of the transmission system. The simulation results show that this scheme can ensure information transmission quality and effectively achieve wavelength adding and dropping, further verify the feasibility of the scheme.

Abstract: Because of different working frequencies, the coherent transmitting mode and other factors, the IF signals form satellite simulator are difficult to fix on the same frequency, which affects the generality of satellite simulator. This paper uses the Doppler extraction technology and software radio technology to study the coherent transmitting of carrier signal. It makes the IF acquisition stick to 70MHz and ensures the uplink & downlink carrier signals coherent. At last the generality problem is solved.

Abstract: This paper analyzes the neural network algorithm model, introduces the basic principles and training process of BP neural network algorithm, analyzes the BP neural network weights adjustment processand the method of determining the number of nodes in each layer; in improved protocol algorithm basis LEACH-E, combined with the BP neural network algorithm, we propose a new data fusion algorithm BPDFA to reduce energy consumption to attain the network lifetime goal.