A Time-slice Based Hybrid Routing for Delay Tolerant Networks

Abstract: The non-existence of an end-to-end path poses a challenge in adapting the traditional routing algorithms to delay tolerant networks (DTNs). This paper innovatively puts forward the concept of "time-slice" to make full use of the respective advantages of single copy strategy and multiple-copy strategy thus getting a right balance between high message delivery ratio and low network overloads. We investigate making the routing decision based only on no more than one-hop information of neighbor nodes so as to enhance the practicability of our routing by reducing the complexity of neighbor discovery. Then a time-slice based hybrid routing protocol is proposed. Simulation results show that our proposed routing achieves the overall best performance than other protocols. When the network resource is constrained, our proposed routing scheme is more scalable than others

Dynamic Groups Based Adaptive DTN Routing Algorithms in Social Networks

Due to the nonexistence of end-to-end path between the sender and the receiver in delay tolerant networks and mobile social networks, consequently successful message transmission faces great challenges. In this paper, an adaptive routing algorithm taking full use of gregariousness characteristics of moving nodes is proposed. We first abstract all social relationships and uniformly represent them using friendship. Then by dynamically dividing nodes into different social groups, we finish flooding message among the target social group where destination node resides. In addition, we propose a social group based flooding model and a message redundancy control model to select fewer but better relay nodes and further reduce message redundancy. Extensive simulations have been conducted based on the synthetic traces generated by working day movement model and the results show that the proposed routing algorithm can get a higher message delivery ratio and a lower overhead ratio compared to Bubble Rap, Epidemic, and ProPHET, thus proving a better routing performance

A Graph-Based Representation Method for Fashion Color

Fashion color research takes the color information of fashion apparel as the major focus for further studies, such as style categorization or trend prediction. However, the colors in apparel are treated as isolated elements from each other, disregarding the fact that not only the attributes of each color itself but also the collocation relationship of the colors in apparel are important color factors. To provide a more comprehensive abstraction of the information from the fashion colors as well as emulating the human cognition of fashion colors, in this paper, we are the first to propose a knowledge graph-based representation method that captures not only the individual colors but also abstracts the spatial relation of all the colors that appear in a single piece of fashion apparel. This method provides the fundamental definition of the abstraction of the relation of colors, a detailed method to construct the color graph, as well as the practical matrix-based management and the visualization of the constructed graphs. The case studies for color data extraction and extended usage demonstrate the effectiveness of our method with comprehensive color data representation and effective information extraction

A Data Item Selection Mechanism for Mobile Opportunistic Networks

The nonexistence of an end-to-end path poses great challenges to directly adapting the traditional routing algorithms for Internet and mobile ad hoc networks (MANETs) to mobile opportunistic networks (MONs). In this paper, we try to improve the routing performance by resorting to an efficient data item selection mechanism that takes the bandwidth and connection duration time into consideration. For the purpose of evaluation, a specific data item selection mechanism for a probability-based routing is devised, which is formally defined as an optimal decision-making problem and solved by the dynamic programming technique. The simulation results show that our data item selection mechanism greatly reduces the number of aborted transmissions thus enhancing the routing performance in aspects of delivery probability, average latency, and overhead ratio

A Graph-Based Representation Method for Fashion Color

Fashion color research takes the color information of fashion apparel as the major focus for further studies, such as style categorization or trend prediction. However, the colors in apparel are treated as isolated elements from each other, disregarding the fact that not only the attributes of each color itself but also the collocation relationship of the colors in apparel are important color factors. To provide a more comprehensive abstraction of the information from the fashion colors as well as emulating the human cognition of fashion colors, in this paper, we are the first to propose a knowledge graph-based representation method that captures not only the individual colors but also abstracts the spatial relation of all the colors that appear in a single piece of fashion apparel. This method provides the fundamental definition of the abstraction of the relation of colors, a detailed method to construct the color graph, as well as the practical matrix-based management and the visualization of the constructed graphs. The case studies for color data extraction and extended usage demonstrate the effectiveness of our method with comprehensive color data representation and effective information extraction

A General and Specific Utility-Based Adaptive Routing for Delay Tolerant Networks

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

A Statistical Analysis Based Probabilistic Routing for Resource-Constrained Delay Tolerant Networks

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 intermeeting 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

A Hop Count Based Heuristic Routing Protocol for Mobile Delay Tolerant Networks

Routing in delay tolerant networks (DTNs) is a challenge since it must handle network partitioning, long delays, and dynamic topology. Meanwhile, routing protocols of the traditional mobile ad hoc networks (MANETs) cannot work well due to the failure of its assumption that most network connections are available. In this paper, we propose a hop count based heuristic routing protocol by utilizing the information carried by the peripatetic packets in the network. A heuristic function is defined to help in making the routing decision. We formally define a custom operation for square matrices so as to transform the heuristic value calculation into matrix manipulation. Finally, the performance of our proposed algorithm is evaluated by the simulation results, which show the advantage of such self-adaptive routing protocol in the diverse circumstance of DTNs