Abstract The main aim of this study was to assess what range downstream low flow changes is caused by dam construction directly. An investigation based on the assumption that difference in change ratio between gauging cross-sections located and upstream position dammed reservoir identifies scope determined construction. Three reservoirs Polish rivers were selected for analysis. They different s...

In this paper the concept of the Minimum Universal Cost Flow (MUCF) for an infeasible flow network is introduced. A new mathematical model in which the objective function includes the total costs of changing arc capacities and sending flow is built and analyzed. A polynomial time algorithm is presented to find the MUCF.

Given a directed graph G = (N,A) with arc capacities uij and a minimum cost flow problem defined on G, the capacity inverse minimum cost flow problem is to find a new capacity vector û for the arc set A such that a given feasible flow x̂ is optimal with respect to the modified capacities. Among all capacity vectors û satisfying this condition, we would like to find one with minimum ‖û− u‖ value....

This paper introduces a scalable maxmin flow control protocol which guarantees the minimum rate for each connection-oriented flow without requiring per-flow information. The protocol is called MR-ASAP (Minimum Rate guaranteeing Adaptive Source-link Accounting Protocol). MR-ASAP is an extension of ASAP [Tsa98a, Kim99], the first exact maxmin flow control protocol for best-effort connection-orien...

Last lecture we studied duality of linear programs (LP), specifically how to construct the dual, the relation between the optimum of an LP and its dual, and some duality applications. In this lecture, we will talk about another application of duality to prove one of the theorems in combinatorics so called Maximum Flow-Minimum Cut Problem. The theorem roughly says that in any graph, the value of...

An extensive computational analysis of several algorithms for solving the minimum-cost network flow problem is conducted. Some of the considered implementations were developed by the author and are available as part of an open-source C++ optimization library called LEMON (http://lemon.cs. elte.hu/). These codes are compared to other publicly available solvers: CS2, MCF, RelaxIV, PDNET, MCFSimpl...

Economies of scale often appear as decreasing marginal costs, but may also occur as a constraint that at least a minimum quantity should be produced or nothing at all. Taking the latter into account can support decisions about keeping a production site, setting up a new one, establishing new routes in logistics network, and many more. In our work, we define the corresponding problem Minimum Cos...