[Show abstract][Hide abstract] ABSTRACT: Multi-channel multi-interface (MCMI) medium access can provide high-throughput services for wireless ad hoc networks. However, the multi-channel hidden terminal problem and the rendezvous problem must be addressed. This study aims to design a low-cost integrated solution to address the two problems, so as to fully exploit the available wireless interfaces and channels to enhance the network performance, especially the network aggregated throughput. The authors propose a new MCMI synchronisation-based media access control (SMAC) protocol with the operation of two interfaces. Unlike other studies, the authors propose a novel interface classification using a synchronisation interface (SynIF) and a normal interface (NorIF). A synchronisation mechanism and a new channel coordination procedure are operated on SynIF, and data packets can be transmitted on SynIF and NorIF concurrently. All control messages occur only in a variable-length channel coordination window (CCW) on a common control channel. The maximum length of CCW and network throughput are analysed mathematically and the performance of the protocol is validated in ns-2 simulator through comparisons with few other MCMI-MAC protocols. In IEEE 802.11-based multi-interface ad hoc networks, when using MCMI-SMAC, the results show that the network aggregated throughput is enhanced significantly and the protocol overhead is very low.
No preview · Article · Oct 2011 · IET Communications
[Show abstract][Hide abstract] ABSTRACT: This paper proposes a new, energy efficient medium access control (MAC) protocol for wireless sensor networks. Wireless sensor networks consist of thousands of simple nodes. Energy efficiency is primary goal in wireless sensor networks. The new protocol is suitable for low-power consumption while latency is less important. The new protocol called DMDS-MAC which is based on distributed mediation device (DMD) protocol and S-MAC protocol utilizes listening/sleep duty cycle mechanism. And it uses mediation device to synchronize the neighbor nodes temporarily. Then they can communicate each other successfully. This can decrease the cost of the nodes
[Show abstract][Hide abstract] ABSTRACT: The security of multimedia's transmission on Internet is very important. In this paper we have discussed digital watermarking technology and the protocol of fair exchange. Then, the scheme of network manufacture products electronic trading based on fair exchange protocol and digital watermarking technology is presented in this paper. Experiments show that the scheme has the properties of fair exchanging and copyright protection, and it is a good scheme to solve security and fairness problems.
[Show abstract][Hide abstract] ABSTRACT: With the development of the broadband IP platform, the Internet-based collaboration applications not only improve efficiency, but also save money. The paper investigates the network support environment of the virtual laboratory, including the gateway queue mechanism and end-to-end congestion mechanism. Then we analyze the shortcomings of the current mechanisms, and present an adaptive end-to-end congestion mechanism based on the UDP which guarantees minimum rates. Finally, we briefly evaluate our method and discuss how to improve it
[Show abstract][Hide abstract] ABSTRACT: Proper regional difference has positive function to the economy and social development of a country. Without difference, there is no advantage, let alone the full play of the regional comparative advantage. However, the excessive adverse effect on the economy or social development for a country of regional economy difference is very obvious. So, it is the essential to find the absolute difference of the regional economy (standard deviation) Critical point. This text analyzes on this question, set up the regression model of mathematics through the theory, attempt to look for FDI difference critical point of suitable regional economic development of our country, and propose on the basis of this critical point.