scholarly journals Randomized rounding algorithms for large scale unsplittable flow problems

2021 ◽  
Author(s):  
François Lamothe ◽  
Emmanuel Rachelson ◽  
Alain Haït ◽  
Cedric Baudoin ◽  
Jean-Baptiste Dupé
Keyword(s):  
Large Scale ◽  
Randomized Rounding ◽  
Flow Problems ◽  
Unsplittable Flow

scholarly journals Adaptation of Random Binomial Graphs for Testing Network Flow Problems Algorithms

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1716
Author(s):  
Adrian Marius Deaconu ◽  
Delia Spridon
Keyword(s):  
Network Flow ◽  
Large Scale ◽  
Random Network ◽  
Minimum Cost ◽  
Maximum Flow ◽  
Network Flow Problems ◽  
Commodity Flow ◽  
Vast Number ◽  
Flow Problems ◽  
Execution Speed

Algorithms for network flow problems, such as maximum flow, minimum cost flow, and multi-commodity flow problems, are continuously developed and improved, and so, random network generators become indispensable to simulate the functionality and to test the correctness and the execution speed of these algorithms. For this purpose, in this paper, the well-known Erdős–Rényi model is adapted to generate random flow (transportation) networks. The developed algorithm is fast and based on the natural property of the flow that can be decomposed into directed elementary s-t paths and cycles. So, the proposed algorithm can be used to quickly build a vast number of networks as well as large-scale networks especially designed for s-t flows.

scholarly journals Comparing Different Approaches for Solving Large Scale Power-Flow Problems With the Newton-Raphson Method

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 56604-56615
Author(s):  
Manolo D'orto ◽  
Svante Sjoblom ◽  
Lung Sheng Chien ◽  
Lilit Axner ◽  
Jing Gong
Keyword(s):  
Power Flow ◽  
Large Scale ◽  
Flow Problems ◽  
Newton Raphson ◽  
Raphson Method

scholarly journals Efficient Preconditioners for Large Scale Binary Cahn-Hilliard Models

2012 ◽  
Vol 12 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Petia Boyanova ◽  
Minh Do-Quang ◽  
Maya Neytcheva
Keyword(s):  
Large Scale ◽  
Iterative Solution ◽  
Flow Problems ◽  
Hilliard Equation ◽  
Finite Element Discretizations ◽  
Solution Methods ◽  
Iterative Solution Methods ◽  
Preconditioned Iterative ◽  
Cahn Hilliard Equation ◽  
Element Discretizations

AbstractIn this work we consider preconditioned iterative solution methods for numerical simulations of multiphase flow problems, modelled by the Cahn-Hilliard equation. We focus on diphasic flows and the construction and efficiency of a preconditioner for the algebraic systems arising from finite element discretizations in space and the θ-method in time. The preconditioner utilises to a full extent the algebraic structure of the underlying matrices and exhibits optimal convergence and computational complexity properties. Various numerical experiments, including large scale examples, are presented as well as performance comparisons with other solution methods.

Solving large-scale reactive optimal power flow problems by a primal–dual $$\hbox {M}^{2}\hbox {BF}$$ approach

2019 ◽  
Vol 21 (2) ◽  
pp. 485-515 ◽  
Author(s):  
Ricardo B. N. M. Pinheiro ◽  
Leonardo Nepomuceno ◽  
Antonio R. Balbo
Keyword(s):  
Power Flow ◽  
Optimal Power Flow ◽  
Large Scale ◽  
Flow Problems ◽  
Optimal Power ◽  
Primal Dual

scholarly journals Algorithms as Mechanisms: The Price of Anarchy of Relax and Round

2020 ◽  
Author(s):  
Paul Dütting ◽  
Thomas Kesselheim ◽  
Éva Tardos
Keyword(s):  
Optimization Problems ◽  
Price Of Anarchy ◽  
Algorithm Design ◽  
Integer Programs ◽  
Flow Problems ◽  
Pricing Rules ◽  
Wide Range ◽  
Packing Integer Programs ◽  
Unsplittable Flow ◽  
The Traveling Salesman Problem

Many algorithms that are originally designed without explicitly considering incentive properties are later combined with simple pricing rules and used as mechanisms. A key question is therefore to understand which algorithms, or, more generally, which algorithm design principles, when combined with simple payment rules such as pay your bid, yield mechanisms with a small price of anarchy. Our main result concerns mechanisms that are based on the relax-and-round paradigm. It shows that oblivious rounding schemes approximately preserve price of anarchy guarantees provable via smoothness. By virtue of our smoothness proofs, our price of anarchy bounds extend to Bayes–Nash equilibria and learning outcomes. In fact, they even apply out of equilibrium, requiring only that agents have no regret for deviations to half their value. We demonstrate the broad applicability of our main result by instantiating it for a wide range of optimization problems ranging from sparse packing integer programs, over single-source unsplittable flow problems and combinatorial auctions with fractionally subadditive valuations, to a maximization variant of the traveling salesman problem.

Large-Scale Topology Optimization in Fluid Flow Problems

2016 ◽  
Vol 2016.26 (0) ◽  
pp. 2310
Author(s):  
Kentaro YAJI ◽  
Masao OGINO ◽  
Shinji NISHIWAKI ◽  
Kikuo FUJITA
Keyword(s):  
Fluid Flow ◽  
Topology Optimization ◽  
Large Scale ◽  
Flow Problems

scholarly journals Experiments with the interior-point method for solving large scale Optimal Power Flow problems

2013 ◽  
Vol 95 ◽  
pp. 276-283 ◽  
Author(s):  
Florin Capitanescu ◽  
Louis Wehenkel
Keyword(s):  
Interior Point ◽  
Interior Point Method ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Large Scale ◽  
Point Method ◽  
Flow Problems ◽  
Optimal Power

Large scale hydrothermal optimal power flow problems based on interior point nonlinear programming

2000 ◽  
Vol 15 (1) ◽  
pp. 396-403 ◽  
Author(s):  
Hau Wei ◽  
H. Sasaki ◽  
J. Kubokawa ◽  
R. Yokoyama
Keyword(s):  
Nonlinear Programming ◽  
Interior Point ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Large Scale ◽  
Flow Problems ◽  
Optimal Power

scholarly journals Solving Large-Scale Linear Multicommodity Flow Problems with an Active Set Strategy and Proximal-ACCPM

2006 ◽  
Vol 54 (1) ◽  
pp. 184-197 ◽  
Author(s):  
F. Babonneau ◽  
O. du Merle ◽  
J.-P. Vial
Keyword(s):  
Large Scale ◽  
Multicommodity Flow ◽  
Active Set ◽  
Active Set Strategy ◽  
Flow Problems

Challenges in Modeling Ground Flares Using Computational Fluid Dynamics

2004 ◽  
Author(s):  
Philip Diwakar ◽  
Vibhor Mehrotra ◽  
Rimon Vallavanatt ◽  
Thomas McLean
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Scale ◽  
National Standard ◽  
Complex Nature ◽  
Large Area ◽  
Length Scales ◽  
Flow Problems ◽  
Varying Length ◽  
Wet Ground

Industrial application of Computational Fluid Dynamics (CFD) are varied and many. However CFD requires the solution of complex fluid-flow problems in conjunction with equipment design, process and product development and optimization. The solution of such complex problems is possible through the coordination between industrial CFD engineers, software developers, consultants and academic scientists. In the petrochemical industry, CFD may be used for a variety of purposes such as air recirculation studies in LNG plants, burners in coker furnaces, multiphase studies in heat exchangers to name just a few. In particular combustion, flames, flares and chemical reaction are of interest because of the physics and the complex nature of the process. The topic selected for this presentation is the study of wet ground flares during a large-scale propane release and the effect of the radiation release on the environment and surrounding buildings and vegetation. The flare characteristics and radiation on the surrounding terrain form an integral part of the information required by the National standard for “Control of Major Hazard Facilities”. The study of individual flames from each burner with nozzles of the order of 1mm and the effect of 180 burners in a large area and surrounding terrain with length scales of several hundred meters make up a very intriguing problem of varying length scales. The results of this analysis are presented concentrating on the effects during the large scale conflagration event on the surrounding buildings, vegetation, aircraft, hills and mangroves.

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