Redundant Messages Research Articles

A Multi-Hop Broadcast Protocol for Emergency Message Dissemination in Urban Vehicular Ad Hoc Networks

In vehicular ad hoc networks (VANETs), multi-hop wireless broadcast has been considered a promising technology to support safety-related applications that have strict quality-of-service (QoS) requirements such as low latency, high reliability, scalability, etc. However, in the urban transportation environment, the efficiency of multi-hop broadcast is critically challenged by complex road structure, severe channel contention, message redundancy, etc. In this paper, we propose an urban multi-hop broadcast protocol (UMBP) to disseminate emergency messages. To lower emergency message transmission delay and reduce message redundancy, UMBP includes a novel forwarding node selection scheme that utilizes iterative partition, mini-slot, and black-burst to quickly select remote neighboring nodes, and a single forwarding node is successfully chosen by the asynchronous contention among them. Then, bidirectional broadcast, multi-directional broadcast, and directional broadcast are designed according to the positions of the emergency message senders. Specifically, at the first hop, bidirectional broadcast or multi-directional broadcast conducts the forwarding node selection scheme in different directions simultaneously, and a single forwarding node is successfully chosen in each direction. Then, directional broadcast is adopted at each hop in the message propagation direction until the emergency message reaches an intersection area where multi-directional broadcast is performed again, which finally enables the emergency message to cover the target area seamlessly. Analysis and simulation results show that the proposed UMBP significantly improves the performance of multi-hop broadcast in terms of one-hop delay, message propagation speed, and message reception rate.

Buffer management for streaming media transmission in hierarchical data of opportunistic networks

An opportunistic network is a kind of novel and self-organizing mobility network with DTN (Delay Tolerant Networks) features, which has no fixed topological structure and transfers messages using the opportunity of nodes encountering. Transmitting steaming media in such a network faces significant challenge, since the topology between source node and destination node is variable. In order to increase the delivery ratio, an opportunistic network employs the message redundancy mechanism, which leads to the existing of multiple copies of messages in different routes at the same moment. These duplicates tend to jam the network, block later messages and jeopardize network performance due to the limited buffer resource of nodes. In this context, we propose a novel buffer management algorithm for streaming media (BMSM) in an opportunistic network by combining the characters of opportunistic networks with the feature of hierarchical data encoding of H.264 streaming media. The BMSM algorithm fully utilizes the real-time dynamic parameters of the network, i.e., remaining living time and the estimation of message copies, and it automatically assigns a priority parameter to a message to determine its transitivity and priority in the node׳s buffer sequence based on the hierarchical property of the messages. By combining the mobility of nodes, a new queuing strategy for managing the buffer is also proposed in BMSM, in which a message is forwarded preferentially to the interacting closely truck nodes when it is at the head of the sequence. Simulation results show that the proposed BMSM algorithm effectively improves the delivery rate and limited the network overhead ratio and thereby ensures the continuous media streams.

A study on effective flooding over MANET based on exchange of neighbor information

When a disaster happens, a mobile ad hoc network is a useful and temporary network. In this situation, it is difficult to assign a unique IP address to each node. Although simple flooding can be used without addresses, it causes redundant message transmission and wastes battery resources. This paper proposes effective flooding based on neighbor information exchange-revised, which reduces power consumption by decreasing the number of redundant messages. Through computer simulation, we show the effectiveness of our method compared with the existing Simple Flooding method.

A social-aware routing protocol for opportunistic networks

Understanding nodes mobility is of fundamental importance for data delivery in opportunistic and intermittently connected networks referred to as Delay Tolerant Networks (DTNs). The analysis of such mobility patterns and the understanding of how mobile nodes interact play a critical role when designing new routing protocols for DTNs. The Cultural Greedy Ant (CGrAnt) protocol is a hybrid Swarm Intelligence-based approach designed to address the routing problem in such dynamic and complex environment. CGrAnt is based on: (1) Cultural Algorithms (CA) and Ant Colony Optimization (ACO) and (2) operational metrics that characterize the opportunistic social connectivity between wireless users. The most promising message forwarders are selected via a greedy transition rule based mainly on local information captured from the DTN environment. Whenever global information is available, it can also be used to support decisions. We compare the performance of CGrAnt with Epidemic, PROPHET, and dLife protocols in two different mobility scenarios under varying networking parameters. Results obtained by the ONE simulator show that CGrAnt achieves a higher message delivery and lower message redundancy than the three protocols in both scenarios. The only exception is in one of the scenarios, when messages have a time to live lower than 900 min, where CGrAnt delivers a bit less messages than dLife, although with a lower message redundancy.

Efficient Fuzzy Logic Based Probabilistic Broadcasting for Mobile Ad hoc Network

AbstractIn Mobile Ad hoc networks broadcasting is the one of the most important and crucial phenomenon. Broadcasting can be taken up in many ways and the simplest method of broadcasting is simple flooding which can significantly increase the overheads and can result in redundant messages which can further cause the Broadcasting Strom problem. In this paper, we propose an efficient fuzzy logic based probabilistic broadcasting for AODV protocol in order to reduce overheads. The fuzzy based logic criteria make decisions which are based on some of the important parameters affecting broadcasting like number of neighbors, bandwidth available and remaining energy. The simulation result shows that the proposed algorithm is efficient and reliable with respect to the consumed power, throughput, overhead, collision rate and it also maintains low normalized routing load as compared to AODV and other routing protocols proposed in the literature in which simple flooding or fixed probability broadcasting is used.

Probability Forwarding Method in Mobile Wireless Sensor Networks

Mobile wireless sensor networks without infrastructure are constructed including the mobile sink layer and the fixed sensor layer. The mobile sinks can communicate with the other mobile sinks. Every mobile sink receives data from the sensors and fuses to build a message. The message is copied, stored, and carried by mobile sinks and then it is transferred to the access point. In this paper, with multiple copies method of epidemic routing we present a probability forwarding scheme for message copies based on the threshold of nodes encountering each other. The method can decrease the message redundancy effectively, and control the waste of resource, bandwidth and energy arisen by a great deal of copies. At the same time, it guarantees the message transferred successfully. The theory analysis and the simulation experiment show that the delivery efficiency of our method is the same as one of epidemic routing, while the delay and the hop count do not increase and copies are fewer.

An adaptive and efficient buffer management scheme for resource-constrained delay tolerant networks

Provisioning buffer management mechanism is especially crucial in resource-constrained delay tolerant networks (DTNs) as maximum data delivery ratio with minimum overhead is expected in highly congested environments. However, most DTN protocols do not consider resource limitations (e.g., buffer, bandwidth) and hence, results in performance degradation. To strangle and mitigate the impact of frequent buffer overflows, this paper presents an adaptive and efficient buffer management scheme called size-aware drop (SAD) that strives to improve buffer utilization and avoid unnecessary message drops. To improve data delivery ratio, SAD exactly determines the requirement based on differential of newly arrived message(s) and available space. To vacate inevitable space from a congested buffer, SAD strives to avoid redundant message drops and deliberate to pick and discard most appropriate message(s) to minimize overhead. The performance of SAD is validated through extensive simulations in realistic environments (i.e., resource-constrained and congested) with different mobility models (i.e., Random Waypoint and disaster). Simulation results demonstrate the performance supremacy of SAD in terms of delivery probability and overhead ratio besides other metrics when compared to contemporary schemes based on Epidemic (DOA and DLA) and PRoPHET (SHLI and MOFO).

High quality information extraction and query-oriented summarization for automatic query-reply in social network

In this paper, we propose a new method for automatic query-reply in social network. Information extraction and query-oriented summarization method are applied here to reply people’s query. There are few effective and commonly used methods on filtering the redundancy and noise of the raw data, which results in the poor quality of the reply. Due to the characteristics of social network messages, we pay more attention to reducing the noise and eliminating the redundancy of the messages to ensure the quality of the final reply. First, we propose an information extraction method to extract high quality information from social network messages, which is based on time-frequency transformation. Second, query-oriented text summarization is implemented to generate a brief and concise summary as the final reply, which is based on the scoring, ranking and selection of sentences of high quality social network messages produced by previous step. Experimental results show that the research is effective in filtering the redundancy and noise of social network messages, the final query-reply results outperform other commonly used methods’ results in both automatic evaluation and manual evaluation. Through our approach, noise and redundancy of social network messages are effectively filtered. Certainly, our method improves the quality of the reply for people’s query.

Probabilistic routing algorithm based on contact duration and message redundancy in delay tolerant network

SummaryThe Delay Tolerant Network (DTN) is a novel Wireless Sensor Network architecture for an opportunistic network environment, in which environment end‐to‐end connection cannot be set up constantly between source and destination nodes pairs. In this paper, we have proposed a novel routing algorithm based on a hybrid of message delivery probability and message redundancy to reduce the communication overhead while keeping the high message delivery ratio. In this algorithm, the message delivery probability is calculated by the combined impact of meeting frequency and length of contact duration. Further, the maximum number of copies of the message is designated in the source node, and the forwarding task of message copies is assigned to relay nodes based on the pattern of a binary tree, so that multi‐path parallel transmission can be implemented on message forwarding. Simulated results showed that the proposed routing algorithm can achieve a higher efficiency of message delivery than the related existing routing algorithms and it can also reduce the communication overhead significantly in general DTNs. Copyright © 2015 John Wiley & Sons, Ltd.

A Knapsack-based buffer management strategy for delay-tolerant networks

In delay-tolerant networks, the dramatic change of topology and the frequent interruption of connections make it difficult to forward the message to destination. Routing protocols in DTNs seek to improve the delivery ratio through increasing the number of message copies. However, the redundant message copies easily cause the occurrence of buffer’s overflowing. In this paper, in order to maximize the utilization of network resources, especially when the bandwidth is limited and the message sizes are different, we present a theoretical framework called the Knapsack-based Message Scheduling and Drop strategy in Theory (KMSDT) based on Epidemic routing protocol. KMSDT sorts the messages in the buffer according to the per-unit utility and, if buffer overflows, decides which message to drop based on the solution to the knapsack problem. Furthermore, a practical framework called the Knapsack-based Message Scheduling and Drop strategy in Practice (KMSDP) is also developed. Rather than collecting the global statistics as done in KMSDT, KMSDP estimates all the parameters through the locally-collected statistics. Simulations based on both synthetic and real mobility traces are done in ONE. Results show that, without affecting the average delay and overhead ratio, KMSDP and KMSDT achieve better delivery ratio than other congestion control strategies.

Lightweight Reprogramming and Energy Balancing in Wireless Sensor Networks

Reprogramming in wireless sensor networks is important and challenged by the dynamic environment and its own characteristic, frequently sleeping. Although there has existed various approaches, they still suffer from message control redundancy and energy balancing issues. In this paper, we consider the problem of lightweight code distribution and energy balancing in wireless sensor networks by utilizing shared requests to reduce redundant control messages. Additionally, our contribution is enhanced by various solutions, such as multisegment advertisement strategy and edge-oriented strategy. Through analysis and evaluation sections, we confirm that our protocol does not only help to reduce update completion time by 1/3 compared with the Deluge protocol, but also significantly decreases redundant control messages and balances energy consumption among nodes in the updating process.

A High Efficient and Real Time Data Aggregation Scheme for WSNs

Data aggregation is an important method of improving transmitting efficiency of WSNs, but existing researches have some disadvantages as follows: several periods delay will be generated when filtering messages; the reduplicated messages filtering ratio is low; complex calculations need to be executed; and extra hardware should be added to obtain high performance. To resolve these problems, this paper proposes a real time and high efficient data aggregation scheme (dynamical message list based data aggregation, DMLDA) based on clustering routing algorithm. DMLDA includes three procedures: activating nodes, clustering nodes, and filtering messages. In filtering procedure, a special data structure named dynamic list will be established in every filtering node; it is designed to store messages transmitted by filtering node, and, comparing current message with list's items, the message's redundancy can be judged without any delay. To improve the filtering efficiency, the message list can be adjusted dynamically. The three procedures of data aggregation are all introduced, and the filtering method is designed in detail in this paper. At last, a series of experiments are simulated to prove our scheme's performance, and the advantages are analyzed in theory.

Messages conveyed by assorted facets of the dewlap, in both sexes of Anolis sagrei

Dewlaps of Anolis lizards are complex multicomponent signaling devices that have been intensively studied. Yet, the functions and multiple messages conveyed by the dewlap remain largely unknown. Here, we assess some aspects of sexual identity, individual quality, and social status that may be signaled by the dewlap in both sexes of Anolis sagrei. In addition, we investigate whether diverse facets of dewlap signaling provide additive information (redundant message hypothesis) or highlight different characteristics of the sender (multiple-message hypothesis). To do so, components of dewlap design (area, color, and pattern ratio) and use (dewlap extension frequency during intersexual context) were quantified and investigated for relationships with sexual identity (sex), individual quality (performance and health state measurements), and social status (mirror-motivated aggression). First, we found that body size together with relative dewlap area and color act as redundant messages in the advertisement of sexual identity. Second, we found that dewlap coloration in the center and edge region signals aspects of individual quality, specifically health state, but only in males. The dewlap center and edge acts primarily as redundant signals, at least for body condition and immune response. However, different color components irrespective of dewlap region convey nonredundant information about aspects of health state in males, supporting the multiple-message hypothesis. Surprisingly, dewlap use in A. sagrei males conveyed no information about the tested quality measurements nor about mirror-motivated aggression. Neither dewlap design nor use in females was related to any of these parameters. In contrast to males, correlations between components of dewlap design and use during intersexual interactions were found for females, suggesting important signaling functions of the female dewlap in a courtship context.

Increasing Survivability of DSRC Safety Applications through Dissimilarity and Redundancy without Altering Existing Standards

Intelligent Transportation Systems (ITS) are considered one of the most critical infrastructures. For wireless communication ITS uses communications links based on Dedicated Short Range Communication (DSRC) in Wireless Access in Vehicular Environments (WAVE) systems, which is a promising technology to improve traffic safety and reduce highway fatalities. Much research has focused on supporting WAVE safety applications, which depend on many message types. Most important to safety applications is the Basic Safety Message (BSM) as defined in the SAE J2735 Message Set Dictionary Standard. We investigate the survivability of this message exchange, as the industry is moving to the implementation phase, particularly due to the criticality of the system. Therefore fault-tolerance and survivability considerations have to be designed into the system, rather than addressed in an add-on fashion. In this paper we will first give required information introduced by different standards related to this topic. Then we will investigate data reliability of safety application message exchanges for selected scenarios. Finally we propose survivability solutions based on dissimilarity and message redundancy, which only rely on the existing standards.

Efficient Parallel Processing of Distance Join Queries Over Distributed Graphs

Distance join queries have recently been recognized as a particularly useful operation over graph data, since they capture graph similarity in a meaningful way. Consequently, they have been studied extensively in recent years [1], [2]. However, current methods are designed for centralized systems, and rely on the graph embedding for effective pruning and indexing. As graph sizes become very large and graph data must be deployed in the distributed environment, these techniques become impractical. In this work, we propose a solution for efficient parallel processing of distance join queries over distributed large graphs. There have been emerging efforts devoted to managing large graphs in distributed and parallel systems. Programming models like Pregel [3] and iterative computing framework like HaLoop [4] have been proposed to handle queries over distributed graphs. However, they are designed in the perspective of functionality instead of the query efficiency. In this work, we define an optimization problem: combining the iterative join and the graph exploration method to minimize the evaluation time of distance join queries. Without sacrificing a system's scalability, our technique exploits a light-weight vertex centric encoding schema built on a distance-aware partition of the entire graph. Extensive experiments over both real and synthetic large graphs show that, by employing an adaptive query plan generation and scheduling method, we can effectively reduce the redundant message passing and I/O costs. Compared to simply using iterative join or graph exploration method, our solution achieves as many as one order of magnitude of time saving for the query evaluation.

A traffic-efficient message forwarding approach in unstructured P2P networks

With more and more peer-to-peer (P2P) applications being utilized, the P2P traffic accounts for the majority in Internet, and thus leading to the network congestion problem. Reducing the redundant propagations of messages is an effective approach for solving such problem in unstructured P2P networks. In this paper, we first define a novel message structure which contains the information of message propagation path, and then three operations, including the inheritance, supplement and collection, on the message transmission paths are proposed, based on which a node could forward the message to the nodes who have not received the message yet purposefully by using the information of the past received messages and the characteristics of space and time of node activities, and thus eliminating the bandwidth consumption problem caused by the flooding-based message propagation approaches. The simulation results show that our strategy could effectively reduce the number of the redundant messages without lowering the message coverage ratio.

Advanced security analysis of a signature scheme with message recovery

Chang et al. proposed a new digital signature scheme with message recovery. However, several forgery attacks demonstrated that Chang et al.'s construction without using one-way hash functions and message redundancy is insecure. Nevertheless, it is unclear to see how to achieve the attacks. In this paper, more general forgery attacks are described to show clearly how to obtain these attacks. It is interesting that our general forgery covers all the known attacks.

CYBERSPACE: A VENUE FOR TERRORISM

This paper discusses how cyberspace has become a venue for terrorists groups for recruiting and proliferating propaganda and terrorism. Moreover, this study explores how the low cost Internet infrastructure and social media sites (such as Facebook, Twitter, and YouTube) have contributed to their networking and operations due to the convenience, in terms of availability, accessibility, message redundancy, ease of use, and the inability to censor content. Concepts such as cyber-weapons, cyber-attacks, cyber-war, and cyber-terrorism are presented and explored to assess how terrorist groups are exploiting cyberspace.

A one-hop information based geographic routing protocol for delay tolerant MANETs

Delay and disruption tolerant networks (DTNs) may lack continuous network connectivity. Routing in DTNs is thus 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, a geographic routing protocol is proposed for MANETs in delay tolerant situations, by using no more than one-hop information. A utility function is designed for implementing the under-controlled replication strategy. To reduce the overheads caused by message flooding, we employ a criterion so as to evaluate the degree of message redundancy. Consequently a message redundancy coping mechanism is added to our routing protocol. Extensive simulations have been conducted and the results show that when node moving speed is relatively low, our routing protocol outperforms the other schemes such as Epidemic, Spray and Wait, FirstContact in delivery ratio and average hop count, while introducing an acceptable overhead ratio into the network.

Efficient Keyword Searching in Large-scale Social Network Service

Different from traditional web searching, the relevant information for a social network system (SNS) is commonly the content from his/her friends. Such a difference makes content indexing extremely difficult for an online social network (OSN) search system because every user has an individual view during searching. Building such a per-user view index over existing SNS Key-Value stores raises a large amount of communication cost due to the complex interconnections among OSN users, making the search system unscalable. To address the problem, we propose a novel protocol called summary index to support keyword searching. In the protocol, each user keeps a directory of the succinct summaries of his/her neighbors, and checks these summaries for potential hits before sending any queries. Two factors contribute to the low overhead of our design: the summary index representations are memory efficient, and the summary dissemination for index updating is communication efficient. First, we design an incremental scalable Bloom filter for summarizing the content constantly generated by a neighbor of a user. For an issued query by a user, the search system first checks against the summary index for a user's neighbor to predict the neighbors likely having desired content. Thus, the search system saves a significant inter-server communication cost by avoiding exhaustively transmitting the query to all the neighbors. Second, to further reduce the overhead for maintaining the social index, we leverage the piggyback strategy which exploits the links with high social strengths to avoid redundant messages during updating the per-user view summary index. We conduct comprehensive simulations using traces from real world systems to evaluate this design. Results show that our scheme significantly outperforms existing schemes for OSN searching in terms of inter-sever traffic by 98 percent.