On the Dynamics of Human Proximity for Data Diffusion in Ad-Hoc Networks

We report on a data-driven investigation aimed at understanding the dynamics of message spreading in a real-world dynamical network of human proximity. We use data collected by means of a proximity-sensing network of wearable sensors that we deployed at three different social gatherings, simultaneously involving several hundred individuals. We simulate a message spreading process over the recorded proximity network, focusing on both the topological and the temporal properties. We show that by using an appropriate technique to deal with the temporal heterogeneity of proximity events, a universal statistical pattern emerges for the delivery times of messages, robust across all the data sets. Our results are useful to set constraints for generic processes of data dissemination, as well as to validate established models of human mobility and proximity that are frequently used to simulate realistic behaviors.Comment: A. Panisson et al., On the dynamics of human proximity for data diffusion in ad-hoc networks, Ad Hoc Netw. (2011

A New Approach to NCL Selection In DTNS Based On a Probabilistic Selection Metric

The propose of caching technique in wireless ADHOC networks profits by the supposition of existing end-to-end ways amidst mobile nodes, and the way from a supplicant to the information source leftovers unaltered every single through data access as a rule. Such supposition empowers any in the middle of node on the way to store the go by information. The accomplishment of such an optional caching procedure is perilously disabled in DTNs, which don't presuppose any persevering system availability. Given that information are sent by means of pioneering contacts, the inquiry and answered information may take distinctive routes, and it is muddled for hubs to gather the data about question times passed by and make caching assumption. To expand the security while efficient data transmission in Disruption tolerant networks adopted AES algorithm is presented which delivers effective security and reduces computation complexity

Exploring centrality for message forwarding in opportunistic networks

In opportunistic networks, centrality characterizes a node's capability to act as a communication hub. In this paper, we provide an in-depth study of choosing effective centrality metrics for message forwarding in bandwidth-limited opportunistic networks. Based on this study, we propose a destination-unaware forwarding algorithm that accounts for the popularity of a node and the contact durations between nodes. We evaluate the algorithm on two experimental human mobility traces. The simulation results show that the proposed algorithm achieves higher system throughput while maintaining a lower forwarding cost compared with several known destination-unaware forwarding schemes. ©2010 IEEE.published_or_final_versionThe 2010 IEEE Conference on Wireless Communications and Networking (WCNC), Sydney, NSW, Australia, 18-21 April 2010. In Proceedings of the IEEE WCNC, 2010, p. 1-

Data Access In Disruption Tolerant Networks Using Cooperative Caching

Disruption tolerant networks (DTNs) consist of mobile devices that call each other opportunistically.Due to the low node density and impulsive nodemobility, only broken network connectivity exists in DTNs, and the ensuing obscurity of maintaining end-to end communication links makes it obligatory to use “carry and-forward” methods for data transmission. Models ofsuch networks consist of groups of individuals moving in adversity mending areas, military battlefields, or urbansensing applications. In such networks, node mobilityis subjugated to let mobile nodes take data as communicate and forward data opportunistically when contacting others. The input difficulty is, consequently, how to decide the suitable communicate assortment plan

Efficient Data Access in Disruption Tolerant Networks Using Cooperative Caching with DRAMA

Disruption Tolerant Networks (DTNs) is characterized by low node density and unpredictable node mobility. The current research efforts in DTN focus on data forward in gand reduce absence of end-to-end path between source and destination, but only limited work has been done on providing efficient data accesses to mobile users. In this paper, we propose a greatly improved energy efficiency strategy named DRAMA aimed to improve storing and fast accessing of data in cache and also it supports cooperative caching in DTNs, which makes the sharing and coordination of cached data among multiple nodes and reduces data access delay. Our idea is to cache data at a set of nodes as network central locations (NCLs), which can be easily accessed by other nodes in the network. We propose an efficient scheme to select appropriate NCL based on probabilistic selection metric and coordinates multiple caching nodes to optimize the trade-off between data accessibility and caching overhead

Congestion aware forwarding in delay tolerant and social opportunistic networks

We propose an approach for opportunistic forwarding that supports optimization of multipoint high volume data flow transfer while maintaining high buffer availability and low delays. This paper explores a number of social, buffer and delay heuristics to offload the traffic from congested parts of the network and spread it over less congested parts of the network in order to keep low delays, high success ratios and high availability of nodes. We conduct an extensive set of experiments for assessing the performance of four newly proposed heuristics and compare them with Epidemic, Prophet, Spay and Wait and Spay and Focus protocols over real connectivity driven traces (RollerNet) and with a realistic publish subscribe filecasting application. We look into success ratio of answered queries, download times (delays) and availability of buffer across eight protocols for varying congestion levels in the face of increasing number of publishers and topic popularity. We show that all of our combined metrics perform better than Epidemic protocol, Prophet, Spray and Wait, Spray and Focus and our previous prototype across all the assessed criteria

Enhancing Performance of Data Access by using Cooperative Caching in Disruption Tolerant Networks

An interruption tolerant system (DTN) is a system outlined so that transitory or irregular correspondences issues, restrictions and peculiarities have the slightest conceivable antagonistic effect Disruption tolerant systems (DTNs) are described by low hub thickness, flighty hub portability, and absence of worldwide system data. The vast majority of ebb and flow research endeavors in DTNs concentrate on information sending, however just work constrained has been done on giving productive information access to portable clients. In this paper, we propose a novel way to deal with bolster agreeable reserving in DTNs, which empowers the sharing and coordination of stored information among different hubs and decreases information access delay. Our fundamental thought is to purposefully reserve information at an arrangement of system focal areas (NCLs), which can be effectively gotten to by different hubs in the system. We propose an effective plan that guarantees fitting NCL choice taking into account a probabilistic choice metric and directions numerous storing hubs to upgrade the tradeoff between information availability and reserving overhead. Broad follow driven recreations demonstrate that our methodology altogether enhances information access execution contrasted with existing plans

Forwarding redundancy in opportunistic mobile networks: Investigation and elimination

Abstract—Opportunistic mobile networks consist of mobile devices which are intermittently connected via short-range radios. Forwarding in such networks relies on selecting relays to carry and deliver data to destinations upon opportunistic contacts. Due to the intermittent network connectivity, relays in current for-warding schemes are selected separately in a distributed manner. The contact capabilities of relays hence may overlap when they contact the same nodes and cause forwarding redundancy. This redundancy reduces the efficiency of resource utilization in the network, and may impair the forwarding performance if being ignored. In this paper, based on experimental investigations on the characteristics of forwarding redundancy in realistic mobile networks, we propose methods to eliminate unnecessary for-warding redundancy and ensure efficient utilization of network resources. We first develop techniques to eliminate forwarding redundancy with global network information, and then improve these techniques to be operable in a fully distributed manner with limited network information. I

Fair Routing in Delay Tolerant Networks

Abstract—The typical state-of-the-art routing algorithms for delay tolerant networks are based on best next hop hill-climbing heuristics in order to achieve throughput and efficiency. The combination of these heuristics and the social network structure leads the routing to direct most of the traffic through a small subset of good users. For instance, in the SimBet algorithm, the top 10 % of users carry out 54 % of all the forwards and 85 % of all the handovers. This unfair load distribution is not sustainable as it can quickly deplete constraint resources in heavily utilized mobile devices (e.g. storage, battery, budget, etc.). Moreover, because a small number of users carry a significant amount of the traffic, the system is not robust to random failures and attacks. To overcome these inefficiencies, this paper introduces Fair-Route, a routing algorithm for delay tolerant networks inspired by the social processes of perceived interaction strength, where messages are preferably forwarded to users that have a stronger social relation with the target of the message; and assortativity, that limits the exchange of messages to those users with similar ”social status”. We compare the performance of FairRoute to the state-of-the-art algorithms by extensive simulations on the MIT reality mining dataset. The results show that our algorithm outperforms existing algorithms in the de facto benchmark of throughput vs. forwards. Furthermore, it distributes better the load; the top 10 % carry out 26 % of the forwards and 28 % of the handovers without any loss in performance. I