CPTR: conditional probability tree based routing in opportunistic networks

In opportunistic networks due to the inconsistency of the nodes link, routing is carried out dynamically and we cannot use proactive routes. In these networks, nodes use opportunities gained based on store-carry-forward patterns to forward messages. Every node that receives a message when it encounters another node makes decision regarding the forwarding or not forwarding the node encountered. In some previous methods, the recognition of whether encounter with current node is considered as an appropriate opportunity or not has been carried out based on the comparison of the probability of carrier node and the node encountered. In these methods, if the message is delivered to the encountered node, a better opportunity would be lost. To fight with this challenge we have posed CPTR method by using conditional probability tree method through which in addition to the probability of the delivery of carrier and encountered nodes’ message delivery, the opportunities for after encounter will be involved in messages’ forwarding. Results of simulation showed that the proposed method can improve the ratio of delivery and delay of message delivery compared to other similar methods in networks with limited buffer.     

FTR: features tree based routing in mobile social networks

Mobile social networks are among subsets of delay tolerant networks. The nodes of these networks are mobile and the communication between them is done wireless and all nodes have social characteristics. The connection between these nodes is temporary and there is not end to end route between the source and the destination. Therefore, it is difficult to deliver the packets to the destination. One of the best routing methods in such networks is to use the information about the network context. These methods require the process of information collection and replicate the packets based on the context to increase the delivery ratio and enforce great overhead onto the network. Since the nodes have social characteristics and these features exist within the network, it seems that using them within the routing can be useful. In this paper a community based method of delivering is proposed that uses social characteristics of the individual members for routing the packets. Using the predetermined roles for the members that do not need data collection level can improve routing in these networks. In this method a tree is formed and each group of the members is entitled in one branch of it. The transmission of the packets from the source to the destination is done based on the differences between their characteristics and through the route which has the highest number of the nodes. The simulation results show that the delivery ratio of this method has increased regarding the related works and the overhead ratio has decreased.

     

SFQ: Social Features Based Quota Routing in Mobile Social Networks

Wireless Personal Communications - Mobile social networks are networks with mobile nodes which have social properties. Various methods for routing have been introduced in these networks. Some of...     

Sharing spray and wait routing algorithm in opportunistic networks

Due to the instability and intermittent connectivity of links among the nodes and the lack of connectivity in opportunistic network, it is not feasible to use common routing for delivering messages. The only practical method for routing and delivering messages is to use the store-carry-forward routing method. As a case in point, spray and wait is considered to be one of the most appropriate routing methods. The efficiency of this method depends directly on the proper selection of the next hop and the number of copies when it encounters a node. In this paper, a method was proposed that constantly selects the next node and considers the number of copies a node can deliver. In the proposed method, the selection of the next node and the number of message copies to be transmitted by the next hop are based on message carrying time and the probability of message delivery. The network model, based on Markov chain, is extended for analysis. Simulation and analysis results showed that significant enhancement is obtained with the proposed method when measuring metrics such as delay, delivery ratio and copy do comparisons with similar methods.     

CTR: Carry Time-Based Routing for Increasing Delivery Ratio in Mobile Social Networks

Wireless Personal Communications - Mobile social network is a kind of social networks through which the nodes have some social features such as: gender, job, friendship relations, centrality, and...     

Determination of Relay Node Based on Fuzzy Logic in Delay Tolerant Network

Wireless Personal Communications - Delay tolerant networks are among mobile ad hoc networks. There is not a complete and connected route between the source and destination in these networks due to...     

Erlang Based Buffer Management and Routing in Opportunistic Networks

Wireless Personal Communications - In opportunistic networks the network’s topology is not connected due to the intermittent links. Thus, to deliver messages there is not a route between the...     

Effect of green GO/Au nanocomposite on in‐vitro amplification of human DNA

Recently nanomaterials have attracted interest for increasing efficiency of polymerase chain reaction (PCR) systems. Here, the authors report on the usefulness of green graphene oxide/gold (GO/Au) nanocomposites for enhancement of PCR reactions. In this study, green GO/Au nanocomposite was prepared with Matricaria chamomilla extract as reducing/capping agent for site‐directed nucleation of Au^o atoms on surface of GO sheets. The as‐prepared green GO/Au nanocomposites were then characterised with UV–VIS spectrophotometer and scanning electron microscopy. Later, the effect of these nanocomposites was studied on end‐point and real‐time PCR employed for amplification of human glyceraldehyde‐3‐phosphate dehydrogenase gene. The results indicated that GO/Au nanocomposite can improve both end‐point and real‐time PCR methods at the optimum concentrations, possibly through interaction between GO/Au nanocomposite and the materials in PCR reaction, and through providing increased thermal convection by the GO surface as well as the Au nanostructures. In conclusion, it can be suggested that green GO/Au nanocomposite is a biocompatible and eco‐friendly candidate as enhancer of in‐vitro molecular amplification strategies.Inspec keywords: graphene, molecular biophysics, nucleation, enzymes, gold, nanofabrication, nanocomposites, scanning electron microscopy, nanoparticles, DNA, nanomedicine, ultraviolet spectra, visible spectra, graphene compoundsOther keywords: green GO/Au nanocomposite, polymerase chain reaction systems, green graphene oxide/gold, PCR reaction, as‐prepared green GO/Au nanocomposites, real‐time PCR methods, Au nanostructures, in‐vitro amplification, human DNA, Matricaria chamomilla extract, site‐directed nucleation, Au, CO, CO‐Au