We consider the Railway Traveling Salesman Problem. We show that this problem can be reduced to a variant of the generalized traveling salesman problem, defined on an undirected graph G = (V, E) with the nodes partitioned into clusters, which consists in finding a minimum cost cycle spanning a subset of nodes with the property that exactly two nodes are chosen from each cluster. We describe an ...

Wavelength assignment algorithm is one of the important components of routing and wavelength assignments problem in WDM networks. This problem helps in the minimization of the blocking probability of the network. In this paper we have reviewed the wavelength assignment problem and discussed the history of this problem with a good literature review. Depending upon the literature and history of t...

Asymptotic behavior of initially "large and smooth" pulses is investigated at two typical stages of their evolution governed by the defocusing nonlinear Schrödinger equation. At first, wave breaking phenomenon is studied in the limit of small dispersion. A solution of the Whitham modulational equations is found for the case of dissipationless shock wave arising after the wave breaking point. Th...