Wyniki wyszukiwania - BazTech

1

Integrated Routing and Network Flow Control Embracing Two Layers of TCP/IP Networks - Methodological Issues

Karboński A.

Journal of Telecommunications and Information Technology

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2012

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nr 2

51-54

EN

A cross-layer network optimization problem is considered. It involves network and transport layers, treating both routing and flows as decision variables. Due to the nonconvexity of the capacity constraints, when using Lagrangian relaxation method a duality gap causes numerical instability. It is shown that the rescue preserving separability of the problem may be the application of the augmented Lagrangian method, together with Cohen's Auxiliary Problem Principle.

2

Lagrangian Relaxation and Linear Intersection Based QoS Routing Algorithm

Stachowiak K., Zwierzykowski P.

International Journal of Electronics and Telecommunications

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2012

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Vol. 58, No. 4

307-314

EN

Due to the process of network convergence, the variety of types of traffic transmitted over a single medium increases steeply. This phenomenon can be handled by the existing networking structure although the protocols that are used and, especially, the underlying routing protocols need to be improved. The problem of finding the shortest path on the Internet can no longer be easily defined as there is an increasing number of different characteristics to describe a point-to-point link. The definition of the shortest path may differ for different traffic types. Therefore, in the mathematical models used to solve the modern routing problems multiple criteria must be taken into account. One of the interesting classes of the optimization problem is the problem of finding the solution that is minimized against one of the criteria under certain constraints with regard to the others. In this paper, two algorithms solving this kind of problems are presented and compared with a new solution proposed by the authors.

3

Wielokryterialne zagadnienie optymalnej lokalizacji centrów dystrybucji typu G/G/1//r

Jakowska-Suwalska K., Wolny M.

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2009

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z. 49

95-104

PL

W pracy przedstawiono nieliniowy, wielokryterialny model optymalnego wyboru z proponowanych n lokalizacji centrów dystrybucji dla obsługi m klientów. Jako kryteria lokalizacji przyjęto minimalizacje czasu realizacji zleceń oraz minimalizację liczby otwartych centrów. Do rozwiązania przyjęto skalaryzację zagadnienia za pomocą metody punktu referencyjnego. Przyjęto, że każde centrum dystrybucji CDj, jest systemem masowej obsługi typu G/G/1//rj, gdzie rj to liczba klientów zaopatrujących się w tym centrum. Dla znalezienia średniego czasu przebywania zgłoszenia w systemie wykorzystano aproksymację dyfuzyjną.

EN

In this paper the author presented multicriteria, nonlinear model of optimal location of distribution centers for m clients when n locations are available. The problem of location centers is formulated with minimization time realization order for every customer and minimization of opening centers. For scalarization of problem is applying the method of reference point. Every of centers CDj is considered as G/G/1//rj queuing system where rj, is number of this center clients. For compute average time in system used diffusion approximation.

4

Design of multi-layer robust telecommunication networks through the dual benders decomposition approach.

Szcześniak M., Pióro M.

Systems Science

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2000

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Vol. 26, nr 1

83-94

EN

We show how the so called dual benders decomposition approach (DBDA), proposed by Minoux and Serrault (1981), can be extended to the optimal design problems of multi-layer networks robust to failures and demand variations considered by Pióro (1998). DBDA substantially enforces the Lagrangian relaxation technique combined with sub-gradient optimisation used in Pióro.