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Takafumi TANAKA Hiroshi HASEGAWA
In this paper, we propose a heuristic planning method to efficiently accommodate dynamic multilayer path (MLP) demand in multilayer networks consisting of a Time Division Multiplexing (TDM) layer and a Wavelength Division Multiplexing (WDM) layer; the goal is to achieve the flexible accommodation of increasing capacity and diversifying path demands. In addition to the grooming of links at the TDM layer and the route and frequency slots for the elastic optical path to be established, MLP requires the selection of an appropriate operational mode, consisting of a combination of modulation formats and symbol rates supported by digital coherent transceivers. Our proposed MLP planning method defines a planning policy for each of these parameters and embeds the values calculated by combining these policies in an auxiliary graph, which allows the planning parameters to be calculated for MLP demand requirements in a single step. Simulations reveal that the choice of operational mode significantly reduces the blocking probability and demonstrate that the edge weights in the auxiliary graph allow MLP planning with characteristics tailored to MLP demand and network requirements. Furthermore, we quantitatively evaluate the impact of each planning policy on the MLP planning results.
This paper introduces a multilayer traffic network model and traffic network clustering method for solving the route selection problem (RSP) in car navigation system (CNS). The purpose of the proposed method is to reduce the computation time of route selection substantially with acceptable loss of accuracy by preprocessing the large size traffic network into new network form. The proposed approach further preprocesses the traffic network than the traditional hierarchical network method by clustering method. The traffic network clustering considers two criteria. We specify a genetic clustering algorithm for traffic network clustering and use NSGA-II for calculating the multiple objective Pareto optimal set. The proposed method can overcome the size limitations when solving route selection in CNS. Solutions provided by the proposed algorithm are compared with the optimal solutions to analyze and quantify the loss of accuracy.
Typical concepts concerning memorizing capability of multilayer neural networks are statistical capacity and Vapnik-Chervonenkis (VC) dimension. These are differently defined each other according to intended applications. Although for the VC dimension several tighter upper bounds have been proposed, even if limited to networks with linear threshold elements, in literature, upper bounds on the statistical capacity are available only by the order of magnitude. We argue first that the proposed or ordinary formulation of the upper bound on the statistical capacity depends strongly on, and thus, it is possibly expressed by the number of the first hidden layer units. Then, we describe a more elaborated upper bound of the memorizing capacity of multilayer neural networks with linear threshold elements, which improves former results. Finally, a discussion of gaining good generalization is presented.