Esquemas de segurança contra ataques de poluição em codificação de rede sobre redes sem fios

Doutoramento em TelecomunicaçõesResumo em português não disponivelThe topic of this thesis is how to achieve e cient security against pollution attacks by exploiting the structure of network coding. There has recently been growing interest in using network coding techniques to increase the robustness and throughput of data networks, and reduce the delay in wireless networks, where a network coding-based scheme takes advantage of the additive nature of wireless signals by allowing two nodes to transmit simultaneously to the relay node. However, Network Coding (NC)-enabled wireless networks are susceptible to a severe security threat, known as data pollution attack, where a malicious node injects into the network polluted (i.e., corrupted) packets that prevent the destination nodes from decoding correctly. Due to recoding at the intermediate nodes, according to the core principle of NC, the polluted packets propagate quickly into other packets and corrupt bunches of legitimate packets leading to network resource waste. Hence, a lot of research e ort has been devoted to schemes against data pollution attacks. Homomorphic Message Authentication Code (MAC)-based schemes are a promising solution against data pollution attacks. However, most of them are susceptible to a new type of pollution attack, called tag pollution attack, where an adversary node randomly modi es tags appended to the end of the transmitted packets. Therefore, in this thesis, we rst propose a homomorphic message authentication code-based scheme, providing resistance against data pollution attacks and tag pollution attacks in XOR NC-enabled wireless networks. Moreover, we propose four homomorphic message authentication code-based schemes which provide resistance against data and tag pollution attacks in Random Linear Network Coding (RLNC). Our results show that our proposed schemes are more e cient compared to other competitive tag pollution immune schemes in terms of complexity, communication overhead and key storage overhead

An Energy-Efficient and Reliable Data Transmission Scheme for Transmitter-based Energy Harvesting Networks

Energy harvesting technology has been studied to overcome a limited power resource problem for a sensor network. This paper proposes a new data transmission period control and reliable data transmission algorithm for energy harvesting based sensor networks. Although previous studies proposed a communication protocol for energy harvesting based sensor networks, it still needs additional discussion. Proposed algorithm control a data transmission period and the number of data transmission dynamically based on environment information. Through this, energy consumption is reduced and transmission reliability is improved. The simulation result shows that the proposed algorithm is more efficient when compared with previous energy harvesting based communication standard, Enocean in terms of transmission success rate and residual energy.This research was supported by Basic Science Research Program through the National Research Foundation by Korea (NRF) funded by the Ministry of Education, Science and Technology(2012R1A1A3012227)

Data bases and data base systems related to NASA's aerospace program. A bibliography with indexes

This bibliography lists 1778 reports, articles, and other documents introduced into the NASA scientific and technical information system, 1975 through 1980

Shut Up and Take My Money: Engaging Facebook Communities to Build the Brand Narrative

Social media is revolutionizing the way firms manage their brands. A broad variety of platforms provide businesses an opportunity to engage in bidirectional dialogue with their customers, the effect of which is to enhance the brand/consumer relationship. This paper contends that virtual brand communities of the type that form through social media have an important role to play in the development of a brand’s personality. Using a case study approach we demonstrate how one firm has adopted Facebook to provide their brand community with a voice which contributes to the development of the brand narrative. We find that by using well-crafted content the firm elicits the support of their community and that this interaction contributes to the development of the brand ethos