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Zhang J.,Xian Institute of Post and Telecommunications | Ansari N.,New Jersey Institute of Technology
IEEE Communications Magazine | Year: 2011

In next generation networks, voice, data, and multimedia services will be converged onto a single network platform with increasing complexity and heterogeneity of underlying wireless and optical networking systems. These services should be delivered in the most cost- and resource-efficient manner with ensured user satisfaction. To this end, service providers are now switching the focus from network Quality of Service (QoS) to user Quality of Experience (QoE), which describes the overall performance of a network from the user perspective. High network QoS can, in many cases, result in high QoE, but it cannot assure high QoE. Optimizing end-to-end QoE must consider other contributing factors of QoE such as the application-level QoS, the capability of terminal equipment and customer premises networks, and subjective user factors. This article discusses challenges and a possible solution for optimizing end-to-end QoE in Next Generation Networks. © 2010 IEEE.

Xuemei H.,Xian Institute of Post and Telecommunications | Hao Y.,Changan University
Journal of Nanomaterials | Year: 2013

Polystyrene microspheres coated with detonation nanographite particles have been prepared by Pickering emulsion polymerization using azobisisobutylonitrile (AIBN) as initiator in aqueous solutions. In the present techniques, the pristine detonation nano-graphite particles were employed as stabilizer of Pickering emulsion and then were armored on the as-prepared polystyrene cores by the thermal polymerization. The composite microspheres of polystyrene/ detonation nano-graphite (PS/DNG) were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA-DTA), and Fourier transformation infrared spectrum (FT-IR). FE-SEM indicates that the resulting samples retain spherical shape, with the uniform size ranging from 100 to 150 m and good dispersity. FT-IR presents the possible formation mechanisms of PS/DNG composites. The functional groups on the surface of polystyrene and modified detonation nano-graphite particles have played an important role for the formation of PS/DNG composites. Moreover, the wettability of different nano-graphite was also tested. © 2013 Hou Xuemei and Ying Hao.

Wu X.,Xian Institute of Post and Telecommunications
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Trust is one of key factors which influence the development of mobile P2P networks. However, current trust evaluation models are not applicable to mobile P2P networks properly due to some of its characteristics such as heterogeneous nature of the peers, limited-range as well as unreliability of wireless links. In the paper main factors that influence the trust in mobile P2P networks are identified. Based on the analyzed result, we propose a novel trust evaluation model, which helps the networks to operate normally with high probability. Our model does not employ cryptographic approaches or certification mechanisms, so it is light enough to fit well with mobile P2P networks without great overheads. In addition, it also effectively solves the trust problem when no prior interaction history exists, an issue that has not been addressed in many models. The proposed model is shown to be robust in the presence of attackers through simulation. © 2010 Springer-Verlag.

Wu Q.,Xian Institute of Post and Telecommunications
ICIC Express Letters | Year: 2011

Hierarchical identity-based Encryption (HIBE) has wide applications in the large network. The main challenge at present is to construct a high efficient and strong secure HIBE with a low computation cost. In this paper, a new construction of HIBE scheme is proposed at first. However, the new scheme only achieves the weak adaptive security. To achieve adaptive security, dual system encryption is applied. The modified scheme has short public parameters and constant size ciphertexts. In addition, the private keys size shrinks as the hierarchy depth increases. The cost of verification only requires two bilinear pairings, which are independent of hierarchy depth. Furthermore, the schemes are provably secure in the standard model. ICIC International © 2011 ISSN 1881-803X.

Zhang L.,Xidian University | Hu Y.,Xidian University | Wu Q.,Xian Institute of Post and Telecommunications
Mathematical and Computer Modelling | Year: 2012

The main challenge in building efficient broadcast systems is to encrypt messages with short ciphertexts. The well-known constructions of identity-based broadcast encryption (IBBE) with constant size ciphertexts in the standard model are based on the non-standard cryptography assumption. In addition, these constructions cannot solve the trade-off between the private keys and ciphertexts. These folklore construction methods lead to schemes that are somewhat inefficient and leave open the problem of finding more efficient direct constructions. In this paper, we give a secure identity-based broadcast encryption scheme with a constant-size ciphertext and private keys. It is constructed by using dual techniques in the subgroups. The proposed scheme achieves the full security (adaptive security) under three static (i.e. non q-based) assumptions. It is worth noting that only recently Waters's scheme achieves adaptive security under simple assumptions. One feature of our scheme is that it is relatively simple to get adaptive security. © 2011 Elsevier Ltd.

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