Showing papers on "Weighted network published in 2002"
TL;DR: It is shown that with the proposed algorithms, the RWA problem with tunnel allocation in the optical networks containing MG-OXCs can be solved effectively and that DTA is outperformed by CB-STA in the same network environment due to a well-disciplined approach for allocating tunnels with CB- STA.
Abstract: We propose a novel switching architecture of multigranularity optical cross-connects (MG-OXCs) for dealing with multigranularity traffic in the optical domain. MG-OXCs can cooperate with the generalized multiprotocol label switching (MPLS) control plane, which provides the advantages of cost reduction, better scalability in physical size, and unified traffic management. Detailed discussions are provided on the characteristics and implementation issues for the switching architecture. Based on the proposed MG-OXCs, two routing and wavelength assignment (RWA) with tunnel allocation algorithms are presented: dynamic tunnel allocation (DTA) and capacity-balanced static tunnel allocation (CB-STA). In the former, we use fixed alternate routing with k-shortest paths to inspect network resources along each alternate path for dynamically setting up lightpaths. For the latter, fiber and waveband tunnels are allocated into networks at the planning stage (or off-line) according to weighted network link-state (W-NLS). We will show that with the proposed algorithms, the RWA problem with tunnel allocation in the optical networks containing MG-OXCs can be solved effectively. Simulation is conducted on networks with different percentages of switching capacity and traffic load. The simulation results show that DTA is outperformed by CB-STA in the same network environment due to a well-disciplined approach for allocating tunnels with CB-STA.. We also find that the mix of the two approaches yields the best performance given the same network environment apparatus.
76 citations
TL;DR: It is shown that among all networks with the small-world structure, the most efficient ones have a "single center" node, from which all shortcuts are connected to uniformly distributed nodes over the network.
Abstract: Efficiency in passage times is an important issue in designing networks, such as transportation or computer networks. The small-world networks have structures that yield high efficiency, while keeping the network highly clustered. We show that among all networks with the small-world structure, the most efficient ones have a "single center" node, from which all shortcuts are connected to uniformly distributed nodes over the network. The networks with several centers and a connected subnetwork of shortcuts are shown to be "almost" as efficient. Genetic-algorithm simulations further support our results.
36 citations
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TL;DR: This work shows how complex systems models can be used to investigate the effects of various parameters in hierarchical and scale-free network structures, and shows that flat hierarchies, which possess few layers and many links per node, are more likely to be unstable than deeper hierarchies.
Abstract: Networks are very evident in the physical world and particularly in social structures. One focus of research is on investigating the development and maintenance of social network structures. Social networks may be typically categorised as random, scale-free or hierarchical structures. A key research question is how the structure and parameters of a network affect the stability of opinion within the network. In a previous study, we examined the case for random network structures. In this work, we show how complex systems models can be used to investigate the effects of various parameters (including the number of layers and the number of links per node) in hierarchical and scale-free network structures. The models are used to investigate whether the network reaches a stable collective state, where the opinions of individuals remain constant, or an unstable state, where the opinions of individuals continue to change. Several important results emerge. One is that flat hierarchies, which possess few layers and many links per node, are more likely to be unstable than deeper hierarchies. Another is that regardless of the network topology, the number individuals whose opinion continues to change settles to a relatively stable level. We also demonstrate the inherent stability of scale-free networks. This work has implications for how network structures should be organized, in order to exploit stability or dynamic behaviour, in particular for political, organisational, social and educational contexts.
34 citations