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Guo L.,Northeastern University China | Guo L.,BeijingUniversity of Posts and Telecommunications | Hou W.,Northeastern University China | Wu J.,Northeastern University China | Li Y.,Northeastern University China
Photonic Network Communications | Year: 2012

In order to improve the bandwidth utilization efficiency and reduce the blocking probability for multicast requests in optical networks, the multicast traffic grooming approach was proposed to groom a lot of low-speed traffic to a few of high-speed light-trees. At the same time, in order to save the ports and the cost of optical cross-connect, the multicast waveband grooming approach was proposed to groom multiple light-trees to a few of waveband tunnels. However, the existing approaches all did not consider the joint performances of improving bandwidth utilization efficiency, reducing blocking probability and saving ports for multicast requests. Therefore, in this article, we propose a new multicast multi-granular grooming approach to perform the hierarchical sequential grooming to improve the joint performances based on a newly developed integrated auxiliary grooming graph (IAGG) that includes multiple wavelength integrated grooming graphs (WIGGs) and onewaveband virtual topology layered graph (BVLG) to support both the multicast traffic grooming and multicast waveband grooming. In order to achieve the map of light-tree to the virtual topology layer in WIGG or BVLG, we present a light-segment map method, where a light-tree will be divided to several lightsegments each of which will be independently mapped to the virtual topology layer. Since different definitions of blocking probability may lead to different objectives, we define two kinds of blocking probability, mean blocking probability of requests (MBPR) and mean blocking probability of users (MBPU). According to the two definitions of blocking probability, we propose two multicastmulti-granular grooming heuristic algorithms, Heuristic Algorithm with minimizingMBPR and Heuristic Algorithm with minimizing MBPU based on IAGG. Simulation results show that the two proposed algorithms are both efficient and have better performances than traditional multicast grooming algorithm. © Springer Science+Business Media, LLC 2012. Source

Zhou J.,Anhui University of Finance and Economics | Zhou J.,University of Science and Technology Beijing | Zhou J.,BeijingUniversity of Posts and Telecommunications | Sun L.,Anhui University of Finance and Economics | And 5 more authors.
Wireless Personal Communications | Year: 2014

The group merging/splitting event is different to the joining/leaving events in which only a member joins or leaves group, but in the group merging/splitting event two small groups merge together into a group or a group is divided into two independent parts. Rekeying is an importance issue for key management whose target is to guarantee forward security and backward security in case of membership changes, however rekeying efficiency is related to group scale in most existing group key management schemes, so as to those schemes are not suitable to the applications whose rekeying time delay is limited strictly. In particular,multiple members are involved in the group merging/splitting event, thus the rekeying performance becomes a worried problem. In this paper, a high performance group merging/splitting group key management scheme is proposed based on an one-encryption-key multi-decryption-key key protocol, in the proposed scheme each member has an unique decryption key that is corresponding to a common encryption key so as to only the common encryption key is updated when the group merging/splitting event happens, however the secret decryption key still keeps unchanged. In efficiency aspect, since no more than amessage on merging/splitting event is sent, at time the network load is reduced since only a group member's key material is enough for other group members to agree a fresh common encryption key. In security aspect, our proposed scheme achieves the key management security requirements including passive security, forward security, backward security and key independence. Therefore, our proposed scheme is suitable to the dynamitic networks that the rekeying time delay is limited strictly such as tolerate delay networks. © Springer Science+Business Media New York 2013. Source

Wang W.,BeijingUniversity of Posts and Telecommunications | Huang Y.,BeijingUniversity of Posts and Telecommunications | Duan X.,BeijingUniversity of Posts and Telecommunications | Guo J.,BeijingUniversity of Posts and Telecommunications | And 3 more authors.
2010 OSA-IEEE-COS Advances in Optoelectronics and Micro/Nano-Optics, AOM 2010 | Year: 2010

This paper investigates the influence of the GaAs substrate on the transmission performance of quarter-wave-stacks' Distributed Brag Reflector (DBR)-based Fabry-Pérot (F-P) filter formed by heteroepitaxial growth, using Transfer Matrix Method (TMM) theoretically. According to our simulation, the designed resonant transmission peak of the filter deteriorates by splitting up with the substrate thickness increasing; furthermore, a rapid oscillation of the Peak-Transmittivity (P-T) of the filter along with the alteration of the substrate thickness is also gained. Finally, a conclusion is achieved that a relatively acceptable transmission spectrum of the filter of this kind can be obtained by thinning the substrate down to a suitable thickness range through well-controlled grinding and polishing. Source

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