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Evolutionary algorithms are metaheuristic algorithms that provide quasioptimal solutions in a reasonable time. They have been applied to many optimization problems in a high number of scientific areas. In this survey paper, we focus on the application of evolutionary algorithms to solve optimization problems related to a type of complex network like mobile multihop ad hoc networks. Since its origin, mobile multihop ad hoc network has evolved causing new types of multihop networks to appear such as vehicular ad hoc networks and delay tolerant networks, leading to the solution of new issues and optimization problems. In this survey, we review the main work presented for each type of mobile multihop ad hoc network and we also present some innovative ideas and open challenges to guide further research in this topic. [ABSTRACT FROM AUTHOR]

Disastrous events are one of the most challenging applications of multihop ad hoc networks due to possible damages of existing telecommunication infrastructure. The deployed cellular communication infrastructure might be partially or completely destroyed after a natural disaster. Multihop ad hoc communication is an interesting alternative to deal with the lack of communications in disaster scenarios. They have evolved since their origin, leading to different ad hoc paradigms such as MANETs, VANETs, DTNs, or WSNs. This paper presents a survey on multihop ad hoc network paradigms for disaster scenarios. It highlights their applicability to important tasks in disaster relief operations. More specifically, the paper reviews the main work found in the literature, which employed ad hoc networks in disaster scenarios. In addition, it discusses the open challenges and the future research directions for each different ad hoc paradigm. [ABSTRACT FROM AUTHOR]

The low penetration of connectivity-enabled OBUs is delaying the deployment of vehicular networks (VNs) and therefore the development of vehicular delay tolerant network (VDTN) applications, among others. In this paper we present GRCBox, an architecture based on RaspberryPi that allows integrating smartphones in VNs. GRCBox is based on a low-cost device that combines several pieces of software to provide ad hoc and multi-interface connectivity to smartphones. Using GRCBox each application can choose the interface for its data flows, which increases flexibility and will allow developers to easily implement applications based on ad hoc connectivity, such as VDTN applications. [ABSTRACT FROM AUTHOR]

Most routing algorithms in delay tolerant networks (DTN) need nodes serving as relays for the source to carry and forward message. Due to the impact of selfishness, nodes have no incentive to stay in the network after getting message (e.g., free riders). To make them be cooperative at specific time, the source has to pay certain reward to them. In addition, the reward may be varying with time. On the other hand, the source can obtain certain benefit if the destination gets message timely. This paper considers the optimal incentive policy to get the best trade-off between the benefit and expenditure of the source for the first time. To cope with this problem, it first proposes a theoretical framework, which can be used to evaluate the trade-off under different incentive policies. Then, based on the framework, it explores the optimal control problem through Pontryagin's maximum principle and proves that the optimal policy conforms to the threshold form in certain cases. Simulations based on both synthetic and real motion traces show the accuracy of the framework. Through extensive numerical results, this paper demonstrates that the optimal policy obtained above is the best. [ABSTRACT FROM AUTHOR]

Machine-to-machine (M2M) networks could be connected by a wide range of wireless technologies (e.g., Bluetooth, WiFi, RFID). Due to some factors (e.g., mobility of machines, limited communication range), it is hard to maintain the connectivity of the network, that is, the network is disconnected and it is a specific application of delay tolerant networks (DTN). Communication in such network often needs nodes working in a cooperative way. However, due to selfishness, nodes have no incentive to help others. Therefore, if the source requests help from other nodes, it needs to pay certain fees to them. The main goal of this paper is to explore efficient ways for the source to maximize the average delivery ratio when the total fees are limited. First, we mathematically characterize the average delivery ratio under different policies. Then we get the optimal policy through Pontryagin's maximum principle, and prove that the optimal policy conforms to the threshold form when the fees that other nodes require satisfy certain conditions. Simulations based on both synthetic and real motion traces show the accuracy of our model. Through extensive numerical results, we demonstrate that the optimal policy obtained by our model is the best. [ABSTRACT FROM AUTHOR]

Efficient data delivery in vehicular sensor networks is still a challenging research issue. Position-based routing protocols have been proven to be more suitable for dynamic vehicular networks or large-scale mobile sensor networks than traditional ad hoc routing protocols. However, position-based routing assumes that intermediate nodes can always be found to set up an end-to-end connection between the source and the destination; otherwise, it suffers from network partitions which are very common in vehicular networks and leads to poor performances. This paper addresses data delivery challenge in the possible intermittently connected vehicular sensor networks by combining position-based forwarding strategy with store-carry-forward routing scheme from delay tolerant networks. The proposed routing method makes use of vehicle driving direction to determine whether holding or forwarding the packet. Experimental results show that the proposed mechanism outperforms existing position-based solutions in terms of packet delivery ratio. [ABSTRACT FROM AUTHOR]

In Delay Tolerant Sensor Networks (DTSN), it is a challenge to ensure the delivery reliability, due to the lack of end-to-end path, intermittent connection, and high latency. In addition, the resource utilization is decreased because of the limited resources and a large number of redundant copies. To this end, this paper proposes an adaptive Socially Aware Feedback Mechanism (SAFM). In this mechanism, the historical information of the encountered nodes is utilized to construct social links which indicates the level of social relationship between nodes. In the feedback process, acknowledgements are forwarded to the nodes whose social link (SL) is higher than a given threshold α. After getting the acknowledgements, nodes will delete the copies of messages which have been received by the destination nodes, so as to reduce the redundancy. This mechanism is to reach a tradeoff between overhead and delivery efficiency. In simulation, the threshold α is obtained to reach the best performance of SAFM. Compared with active and passive receipt approaches in an acceptable range of delay, SAFM improves the delivery probability, decreases the buffer occupancy, and reduces the overhead. [ABSTRACT FROM AUTHOR]

In delay tolerant networks (DTNs), multiple-copy routing is often adopted to improve the probability of successful message delivery but causes more traffic loads. The excessive increase in multiple messages copies often exhausts the network resources and deteriorates its performance significantly. To solve this problem, a mobility similarity-based routing (SBR) algorithm is proposed in this paper. On one hand, destination similarity is used to help the message carrier node find the appropriate relay nodes with the higher opportunity to meet the destination node in order to improve the delivery ratio. On the other hand, carrier similarity is adopted to avoid sending the same copy to the nodes with mobility similarity so as to reduce the number of message copies. Furthermore, inspired by the law of diminishing marginal utility in economics, a buffer management scheme based on the message transmission status is proposed. Experimental results show that the proposed SBR routing algorithm combined with the buffer management scheme can improve the delivery ratio and has the lower overhead ratio compared to other routing algorithms. [ABSTRACT FROM AUTHOR]

Efficient dissemination of messages is a vital solution to the vehicular communications and applications. Geocast, delivering messages to a few specific areas, has become an important issue with the accelerating development of the location-based services in vehicular networks. Different from the conventional geocast schemes focusing on the static target areas, in this paper, we propose a content-based mobile tendency geocast (CMTG) routing protocol for urban vehicular networks from the delay tolerant networks (DTNs) perspective to better deal with the high mobility and transient connectivity issues. The target roads of dissemination depend on the preferred tendency and path of message, based on the determination to the message’s expected propagating roads. And vehicle decides whether to relay the messages carried to other encountered vehicles by calculating the mobile tendency to the source location of message. The robustness and adaptability of protocol are also proved theoretically. Extensive performance comparisons with other protocols are conducted to show the advantages of CMTG. [ABSTRACT FROM AUTHOR]

Recently, the delay tolerant networks (DTN) have been utilized in various operational communication paradigms. This includes the communication scenarios that are subject to disruption and disconnection as well as the scenarios with high delay and frequent partitioning, that is, vehicular ad hoc networks (VANETs). Due to the several characteristics match, new research paradigm named as vehicular delay tolerant networks (VDTNs) is introduced. Through relays and store-carry-forward mechanisms, messages in VDTNs can be delivered to the destination without an end-to-end connection for delay-tolerant applications. However, the choice of routing algorithms in VDTNs is still under study. The main objective of routing protocols in VDTNs is to maximize the probability of delivery at the destination while minimizing the end-to-end delay. Until now, many routing protocols have been proposed to meet requirements of varying applications. In this paper, we, therefore, provide a detailed study of recently proposed routing schemes for VDTNs. We also perform comparative analysis on the basis of unique criterion such as forwarding metrics with their implementations. In addition, open challenges and future directions are provided to make room of interest for the research community. [ABSTRACT FROM AUTHOR]

Vehicular Delay-Tolerant Networks (VDTNs) are a breakthrough based DTN solution used to provide vehicular communications under challenging scenarios, characterized by long delays and sporadic connections. Using the store-carry-and-forward paradigm, this technology allows in-transit bundles to asynchronously reach the destination hop by hop over traveling vehicles equipped with short-range wireless devices. The VDTN architecture assumes out-of-band signaling with control and data planes separation and follows an IP over VDTN approach. This paper presents a real-world VDTN prototype evaluated through a safety application and a Traffic Jam Information Service. It also demonstrates the real deployment of this new vehicular communication approach. The real testbed is an important contribution since some complex issues presented in vehicular communication systems can be studied more accurately in real-world environments than in a laboratory approach. The results confirm that real deployment of VDTNs is doable and can be seen as a very promising technology for vehicular communications, although it requires appropriated technologies for outline interferences and quality of service support. [ABSTRACT FROM AUTHOR]

The nonexistence of an end-to-end path poses great challenges in directly adapting the traditional routing algorithms for ad hoc or mobile ad hoc networks (MANETs) to delay tolerant networks (DTNs). In this paper, an adaptive routing protocol that makes use of both self-aware and destination-aware utility metrics to evaluate the potential throughput between every pair of nodes is proposed. We theoretically analyze the nodes' spraying process and discover the relationship between the initial number of copies and the latency of the message distribution process, by which we can further control the expected latency under a certain level. Compared with Epidemic, Spray And Wait Spray, And Focus and Encounter-based routing, our proposed algorithm is the only one that achieves comparable performance under both Helsinki City Scenario and Cambridge-iMote Scenario. [ABSTRACT FROM AUTHOR]

The nonexistence of end-to-end path between the sender and the receiver poses great challenges to the successful message transmission in delay tolerant networks. Probabilistic routing provides an efficient scheme to route messages, but most existing probabilistic routing protocols do not consider whether a message has enough time-to-live to reach its destination. In this paper, we propose an improved probabilistic routing algorithm that fully takes into account message's time-to-live when predicting the delivery probability. Based on statistical analysis,we compute and update the expected inter meeting times between nodes. And then the probability for a message to be delivered within its time-to-live is computed based on the assumed exponential distribution. We further propose an optimal message schedule policy, by modeling the buffer management problem as 0-1 knapsack, of which the maximum delivery probability sum can be achieved by resorting to the back track technique. Extensive simulations are conducted and the results show that the proposed algorithm can greatly enhance routing performance in terms of message delivery probability, overhead ratio, and average hop count. [ABSTRACT FROM AUTHOR]

Multicopy forwarding schemes have been employed in delay tolerant network (DTN) to improve the delivery delay and delivery rate. Much effort has been focused on reducing the routing cost while retaining high performance. This paper aims to provide an optimal joint expected delay forwarding (OJEDF) protocol which minimizes the expected delay while satisfying a certain constant on the number of forwardings per message. We propose a comprehensive forwarding metric culled joint expected delay (JED) which is a function of remaining hop-count (or ticket) and residual lifetime. We use backward induction to calculate JED by modeling forwarding as an optimal stopping rule problem. We also present an extension to allow OJEDF to run in delay constrained scenarios. We implement OJEDF as well as several other protocols and perform trace-driven simulations. Simulation results confirm that OJEDF shows superiority in delay and cost with acceptable decrease of delivery rate. [ABSTRACT FROM AUTHOR]

Putting forward an efficient routing algorithm in DTN (delay tolerant network) has become a focus of attention due to the existing phenomena that the connections between nodes in the network change dramatically over time and the communications suffer from frequent disruptions. In this paper, the meeting time span between nodes is predicted using the Markov model, and the relay node holding the shortest meeting time span with the destination node is determined as the most efficient node. In the two phases, spray phase and wait phase, the message is routed according to the utility value. Thus, the routing algorithm based on Markov meeting time span prediction model is provided. Simulation results suggest that this algorithm efficiently improves the delivery rate and reduces the average delay. [ABSTRACT FROM AUTHOR]

Delay-tolerant networks are novel wireless mobile networks, which are characterized with high latency and frequent disconnectivity. Besides, people carrying mobile devices form a lot of communities because of similar interests and social relationships. How to improve the routing efficiency in multi-community scenarios has become one of the research hot spots in delay-tolerant networks. In this article, we present a network model of the multi-community delay-tolerant networks and formulate a dynamic quota-controlled routing problem of minimizing the average number of copies of a message that satisfies the required delivery probability under the given time-to-live of the message as a nonlinear optimization problem. To solve this problem, we propose an improved genetic algorithm called genetic algorithm for delivery probability and time-to-live optimization for the dynamic quota-controlled routing scheme to reduce the routing cost further. In addition, a cost-efficient dynamic quota-controlled routing protocol based on genetic algorithm for delivery probability and time-to-live optimization is proposed, which can dynamically adjust message copies according to its assigned delivery probability and time-to-live in different communities on the shortest path. Both the numerical and simulation results show that our routing with the proposed algorithm is more cost efficient. [ABSTRACT FROM AUTHOR]

Sensor nodes around monitoring area have various distances to the target node. Therefore, it is difficult to ensure security of broadcasting data transferred from a single wireless sensor node to base station. Multi-hop transmission of data between sensor nodes wastes network resource. In this case, a distributed data secure transmission scheme is proposed in a wireless sensor network. Data transmission is classified into two stages: constructing a collection of receiving nodes and selecting a unique forwarding node from this collection. These are implemented using analysis of relative movement distance between nodes and transfer time competitive mechanism. Besides, we have assumed a network model for distributed data secure transmission to improve efficiency of data transfer. This design includes secure model of node competition, data perception model, and anti-resistance model. Moreover, the security of competition transfer for nodes in wireless sensor network is evaluated. Finally, simulation proves that the proposed scheme has good performance in security and stability compared to similar schemes. [ABSTRACT FROM AUTHOR]

The vehicular infrastructures or roadside units (RSUs) in vehicular delay tolerant networks (VDTNs) can be used as the gateways of the distributed sensor networks. The different classes of service (CoS) support are desired when more than one type of the sensed data are collected by the RSUs. In this paper, the CoS support traffic scheduling problem for the RSU in VDTNs is considered. By exploring the contact information between the vehicles and the RSU, the CoS traffic scheduling problem is formulated as a maximum weighted triple matching problem, where the traffic scheduling strategy is a timeslot-vehicle-traffic matched pair. A flow network based method is proposed to optimally solve the maximum weighted triple matching problem. Both the offline version and the online version of the traffic scheduling algorithm are developed. Extensive simulations are conducted and the simulation results show the effectiveness and efficiency of the proposed flow network based algorithms. [ABSTRACT FROM AUTHOR]

Based on the research of social network and the Internet of Things, a new research topic in the field of Internet of Things, Social Internet of Things is gradually formed. The SIoT applies the research results of SIoT from different aspects of the Internet of Things, and solves the specific problems in the research of Internet of Things, which brings new opportunities for the development of the Internet of Things. With the development of the Internet of Things technology, in the spatial social Internet of Things structure, user information includes sensitive attributes and non-sensitive attribute information. This information can be inferred from public user information to infer the information of the private user and even speculate on sensitive attributes. This article proposes an information speculation method based on the core users of spatial social networks, and estimates the non-core user information through the core user public information. First, the user's spatial social network is divided into communities, and the core nodes of the community in the spatial social network are calculated by PageRank algorithm and the convergence of the algorithm is proved. Then, through the public information of the core nodes divided by the community in the space social network, the private information of relevant users to these core nodes can be speculated. Finally, by experimental analyzing the community structures of SIoT (Social Internet of Things) like Twitter, Sina Weibo, ER random networks, and NW small-world network, and making 5%, 10%, 15%, 20% information anonymous respectively in these four kinds of networks, we can analyze their clustering coefficient, Q-modularity and properties. Finally, the key node information of the four spatial social structures is speculated to analyze the effectiveness of the proposed method. Compared with the non-core speculation method, this method has advantages in speculative information integrity and time. [ABSTRACT FROM AUTHOR]

In mobile ad hoc networks, network nodes accomplish a target task usually by cooperative packet forwarding from the source to the destination. It is a challenge to enforce their mutual cooperation for a node's self-interest. In this article, we focus on cooperative packet forwarding in a one-hop unreliable channel, which leads to packet loss and retransmission. We model the process of packet forwarding with the nodes' remaining energy and reputation value. We propose a packet-forwarding non-cooperative game model reflecting the utilities of different packet-forwarding strategies, in which an incentive mechanism is introduced to enforce cooperation of packet forwarding. Furthermore, we analyze the packet-forwarding game with replicator dynamics and derive and prove three theorems. If the conditions of the theorems are met, the evolutionarily stable strategies can be attained. Three inferences also reveal how convergence speed to evolutionarily stable states is affected by the cooperative incentive, the probability of successful packet transmissions, and the upper limit of the retransmission number. The simulation results support the proposed theorems and inferences. In addition, we show that our game model with a reputation value and the mechanism of incentive cooperation can improve the probability of successful packet transmissions, and reduce the network overhead. [ABSTRACT FROM AUTHOR]

In delay tolerant networks, the success rate and the transmission speed are restricted by limited social interaction and complex node mobility pattern analysis. To increase the success rate and reduce the transmission delay in delay tolerant networks, we propose Daily Routine Analysis for Node Searching in delay tolerant networks. In Daily Routine Analysis for Node Searching, each node is required to generate a Staying Probability Table and a Transiting Probability Table by analyzing its own daily routine, then to distribute its Staying Probability Table and Transiting Probability Table to the whole network with the help of other nodes having different mobility patterns. On the basis of the Staying Probability Table and Transiting Probability Table, Daily Routine Analysis for Node Searching further provides a node tracking strategy and an opportunistic routing strategy for delivering data from the source node to the destination node. Trace-driven experiments are performed to compare Daily Routine Analysis for Node Searching with previous node searching methods. The experimental results demonstrate that Daily Routine Analysis for Node Searching is able to promote the success rate and reduce the transmission delay effectively. [ABSTRACT FROM AUTHOR]