Applied Mechanics and Materials Vols. 321-324

Abstract: In order to solve the inadequate cache strategy of Kademlia algorithm and the updating of K-bucket, an optimized Kademlia algorithm was proposed. Based on this, a design scheme for P2PSIP VoIP was put forward, analyzed and tested by making experiments with simulation tools.

Abstract: In this paper, electric field shielding effectiveness (SE) of rectangular enclosure with four apertures illuminated by vertical polarization plane wave has been studied by using modal method of moment technique. Electric field SE of enclosure with four square apertures has been calculated at three different points on the same plane inside enclosure. The numerical results of the proposed technique are in very good agreement with data available in the literature and experimental results. It is shown that apertures’ position and aperture’ number have noticeable effect on the electric field SE.

Abstract: Traffic matrix plays a very important role in network management field, such as network design, network optimization, traffic detection, etc. As a result, it is always a hot topic in network research. Based on traditional fanout model, an improved fanout model is proposed to conduct traffic matrix estimation. The model takes into consideration of estimation deviation brought by non-persistent sudden burst of networks flow in a short time, which improves the accuracy of traffic matrix estimation. The simulation shows with algorithm the estimation value has greatly improved in a one-day period.

Abstract: Investigations on broad null steering by only phase perturbation are presented in this paper using immune algorithm (IA) for linear array. Broad null steering in antenna pattern helps to reduce channel interference due to less energy being transmitted at unwanted directions. Phase controlling for broad null steering is relative easy realizing comparing with amplitude or elements’ position controlling. IA is an efficient approach to escape from local convergency for muti-objective optimization with the antibody colony’s diversity is enhanced by using Logistic mapping for initial colony and Gauss function for mutation operator. In this paper, excitation phases are setted as antibodies optimizing for steering broad nulls with specified width at specified directions. Well simulation results show the availability of broad nulling by phase only controlling and the superior global search capability of the improved IA.

Abstract: Packet loss is common in internet, when use IMS mobile terminal accessed by wireless to do real-time voice communication, the quality of speech is affected a lot. This text summarizes the basic principles of AMR-WB encoding and decoding algorithm and main technology of PLC. Based on AMR-WB encoding and decoding algorithm, it improves an algorithm of multi-plus PLC. The algorithm described in this text can speed up the recovery of adaptive-codebook by small bandwidth cost and effectively prevent the spread of errors, improve the quality of speech.

Abstract: The changes caused by the information technology revolution to the society not only improves the science and technology level, but also develops the social information comprehensively. Besides, it leads to the profound reform in the social mode of production and the lifestyle of the ordinary people. The paper does an in-depth analysis and prospect the development trends of the information communication technology from the perspective of relationship among the information society, computer and the Internet, and systematically summarizes the basic characteristics of the information communication technology and the development trend as well as puts forward to the necessity of the close combination of the information communication technology with the user demand.

Abstract: Power Line Communication network has drawn more and more attention and achieved rapid development with its advantages of vast resources and low cost compared with telecommunication network and cable television network. Based on the advantages of Power Line Communication technology, the hardware system was formatted applying four-tier B/S architecture, and the distance learning system based on Power Line Communication technology was established using ASP (Active Server Page) technology. Study shows that the Power Line Communication network is a reliable network learning resources, of great significance to promote distance learning, especially in areas without Internet coverage.

Abstract: This paper presented a approach, called GOHM, for modeling and implementing the architecture of large scale wireless sensor networks(LSWSNs) publish/subscribe(Pub/Sub) applications using a graph-oriented hierarchical model(GOHM). Considering the scalability of topology which was necessary in the LSWSNs, a sparse hierarchical graph(SHG) was defined based on the hierarchical topology model. The simulation indicated that SHG provided low mean-latency at high throughput for transmitting messages. The results imply that SHG can easily be constructed, while ensuring good scalability.

Abstract: A slot-loaded tri-band antenna was designed by electromagnetic simulation software, in which the parameter changes on the antenna centre resonance ratio, such as the location of the antenna coaxial feed point, the width, location, and the length of the slot, were studied. The results show that the length of the slot has the strongest influence on antenna centre resonance ratio.

Abstract: This paper analyzed context aware technology of the computing and applications for large scale sensor networks (LSSNs), proposed the establishment of context aware technology based on active mechanism, and presented active capturing service (ACS) and active knowledge discovery service (AKDS) in computing and applications for LSSNs. The results shows that active mechanism based on event-condition-action (ECA) rules provides an event detection model that suits many classes of applications in ACS and AKDS.