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Wyszukujesz frazę "flow problem" wg kryterium: Temat


Tytuł:
A proposition to exploit the partially linear structure of the nonlinear multicommodity flow optimization problem
Autorzy:
Białoń, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/309255.pdf
Data publikacji:
2002
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
multicommodity flow problem
projection methods
large nonlinear problems
Opis:
Optimization problems arising in telecommunications are often large-scale nonlinear problems. Usually their big size is generated mainly by their linear parts but the existence of small or medium nonlinear parts prevents us from directly tackling them with linear solvers, which are efficient. Instead, the author has proposed a method to decompose big nonlinear problems into nonlinear and linear parts. Its coordination procedure uses two auxiliary solvers: quadratic and pure nonlinear. The procedure falls in the class of projection methods. Special cuts proposed by the author allow to avoid an excessive zigzagging while not enormously increasing the complexity of both the parts. The validity of these cuts can be analyzed within the framework of obtuse cone model. Here the author summarizes the method and analyses its applicability to nonlinear multicommodity flow problems. The structure and particular sizes of this problem make the method useful. The considerations are illustrated by a numerical example with a multicommodity flow problem
Źródło:
Journal of Telecommunications and Information Technology; 2002, 3; 49-56
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tiling by squares, Kirchhoff’s laws and a flow problem in the economy
Autorzy:
Maciuk, Arkadiusz
Smoluk, Antoni
Powiązania:
https://bibliotekanauki.pl/articles/421315.pdf
Data publikacji:
2017
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
squarings
digraph
Kirchhoff’s laws
flow problem in the economy
Opis:
The problem of tiling by squares was formulated more than one hundred years ago and has been mostly regarded as an interesting mathematical issue in geometry, yet without any special practical associations. In addition to a historical outline of the problem, this paper demonstrates how Smith’s 1940 method using digraphs helps associate an issue linked to two-dimensional dissection or packaging with such economic problems as transportation network planning, researching linkages between suppliers and the like. We also discuss simple perfect squared rectangles whose relevant laws of nature are as yet unknown, according to the principle that elegant scientific structures sooner or later find their equivalents in the real world.
Źródło:
Didactics of Mathematics; 2017, 14(18); 33-44
1733-7941
Pojawia się w:
Didactics of Mathematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Analysis of the Problem of Flow Past a Cylindrical Body Applying the R-Functions Method and The Galerkin Method
Autorzy:
Lamtyugova, S.N.
Sidorov, M. V.
Powiązania:
https://bibliotekanauki.pl/articles/410652.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
viscous incompressible fluid
flow problem
R-functions method
Galerkin method
Opis:
The article considers the stationary problem of viscous incompressible fluid flow past a cylindrical body. For solving the problem it is proposed a numerical method, based on the joint use of R-functions method and the Galerkin method. The computational experiment has been conducted for the task of flow past square cylinder for different Reynolds numbers.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2014, 3, 3; 43-50
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adjustable Robust Counterpart Optimization Model for Maximum Flow Problems with Box Uncertainty
Autorzy:
Agustini, Rahmah Arie
Chaerani, Diah
Hertini, Elis
Powiązania:
https://bibliotekanauki.pl/articles/1031851.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Adjustable Robust Counterpart
Linear Programming
Maximum flow problem
Robust Optimization
Opis:
The maximum flow problem is an optimization problem that aims to find the maximum flow value on a network. This problem can be solved by using Linear Programming. The obstacle that is often faced in determining the maximum flow is the magnitude of the capacity of each side of the network can often be changed due to certain factors. Therefore, we need one of the optimization fields that can calculate the uncertainty factor. The field of optimization carried out to overcome these uncertainties is Robust Optimization. This paper discusses the Optimization model for the maximum flow problem by calculating the uncertainties on parameters and adjustable variables using the Adjustable Robust Counterpart (ARC) Optimization model. In this ARC Optimization model it is assumed that there are indeterminate parameters in the form of side capacity in a network and an uncertain decision variable that is the amount of flow from the destination point (sink) to the source point (source). Calculation results from numerical simulations show that the ARC Optimization model provides the maximum number of flows in a network with a set of box uncertainty. Numerical simulations were obtained with Maple software.
Źródło:
World Scientific News; 2020, 141; 91-102
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new polynomial-time implementation of the out-of-kilter algorithm using Minty’s lemma
Autorzy:
Ghiyasvand, M.
Powiązania:
https://bibliotekanauki.pl/articles/205633.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
network flows
minimum cost flow problem
out- of-kilter algorithm
Minty’s lemma
Opis:
It is less well known how to use the out-of-kilter idea to solve the min-cost flow problem because the generic version of the out-of-kilter algorithm runs in exponential time, although it is the sort of algorithm that computers can do easily. Ciupala (2005) presented a scaling out-of-kilter algorithm that runs in polynomial time using the shortest path computation in each phase. In this paper, we present a new polynomial time implementation of out-of-kilter idea. The algorithm uses a scaling method that is different from Ciupala’s scaling method. Each phase of Ciupala’s method needs a shortest path computation, while our algorithm uses Minty’s lemma to transform all the out-of-kilter arcs into in-kilter arcs. When the given network is infeasible, Ciupala’s algorithm does not work, but our algorithm presents some information that helps to repair the infeasible network.
Źródło:
Control and Cybernetics; 2014, 43, 1; 79-94
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient heuristic for non-linear transportation problem on the route with multiple ports
Autorzy:
Krile, S.
Powiązania:
https://bibliotekanauki.pl/articles/260030.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
non-linear transportation problem
Multi-destination Routing Problem
Minimum Cost Multi-Commodity Flow Problem
Capacity Management of Container Ships
Opis:
We need a better transport planning tool for loading maximization and transport cost minimization on the voyage route with multiple loading/unloading (discharging) ports. The implemented heuristic algorithm is able to find out an appropriate routing sequence with maximal earnings and profit. In the same time it looks for minimal loading/discharging and transshipment costs, but with fulfillment of cargo demands in a number of ports on the route. The efficient algorithm for optimal transport of N cargo loads (e.g. contingent of containers) for ships with limited capacity is being developed. This efficient tool may significantly reduce transport costs and ensure maximal profit to freight forwarders. Also, it can be applied for supply chain management of different goods from numerous vendors. The proposed algorithm shows acceptable complexity that means that such optimization tool can be used in shipping supported with limited computing power.
Źródło:
Polish Maritime Research; 2013, 4; 80-86
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testing algorithms for quick rescheduling flow shop problems with FlexSim based simulation and R engine
Autorzy:
Janke, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/27313435.pdf
Data publikacji:
2023
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
flow-shop problem
genetic algorithm
simulation
problem przepływowy
algorytm genetyczny
symulacja
Opis:
Purpose: The aim of this paper is to present a combination of advanced algorithms for finding optimal solutions together with their tests for a permutation flow-shop problem with the possibilities offered by a simulation environment. Four time-constrained algorithms are tested and compared for a specific problem. Design/methodology/approach: Four time-constrained algorithms are tested and compared for a specific problem. The results of the work realisation of the algorithms are transferred to a simulation environment. The entire solution proposed in the work is composed as a parallel environment to the real implementation of the production process. Findings: The genetic algorithm generated the best solution in the same specified short time. By implementing the adopted approach, the correct cooperation of the FlexSim simulation environment with the R language engine was obtained. Research limitations/implications: The genetic algorithm generated the best solution in the same specified short time. By implementing the approach, a correct interaction between the FlexSim simulation environment and the R language engine was achieved. Practical implications: The solution proposed in this paper can be used as an environment to test solutions proposed in production. Simulation methods in the areas of logistics and production have for years attracted the interest of the scientific community and the wider industry. Combining the achievements of science in solving computationally complex problems with increasingly sophisticated algorithms, including artificial intelligence algorithms, with simulation methods that allow a detailed overview of the consequences of changes made seems promising. Originality/value: The original concept of cooperation between the R environment and the FlexSim simulation software for a specific problem was presented.
Źródło:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska; 2023, 168; 163--175
1641-3466
Pojawia się w:
Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation of Nonlinear Water Wave Problems
Autorzy:
Lo, D. C.
Hu, Jia-Shen
Lin, I-Fu
Powiązania:
https://bibliotekanauki.pl/articles/116613.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Weather Navigation
Numerical Simulation
Oceanography
Nonlinear Water Wave Problem
Navier-Stokes Equations
Solitary Waves
Free-Surface Flow Problem
Streamfunction Vorticity Formulation
Opis:
The main purpose of present paper aims at the establishment of a numerical model for solving the nonlinear water wave problems. The model is based on the Navier-Stokes equations with the consideration of a free-surface through the streamfunction-vorticity formulation. The main advantage of the streamfunction-vorticity formulation is that pressure field can be eliminated from the Navier-Stokes equations. To demonstrate the model feasibility, the present studies are first concentrated on problems including the collision of two solitary waves with different amplitudes, and the overtaking collision of two solitary waves. Then, the model is also applied to a solitary wave passes over the submerged obstacle in a viscous fluid. Finally, the application of present study is also to simulate the generation of solitary waves by underwater moving object. All examples give very promising results, those applications reveal that present formulation is a very powerful approach to simulate the fully nonlinear water wave problems.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2008, 2, 2; 137-142
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resource and Task Allocation Algorithm for WAN-based Distributed Computing Environment
Autorzy:
Markowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/226934.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
capacity and flow assignment problem
distributed computing
resource management
wide area networks
Opis:
In the paper an approximate algorithm for optimizing of distributed computing WAN network is proposed. Distributed computing systems become the common tools in different kind of business, science and even entertainment. In order to minimize processing time of data and utilize spare resources available on remote systems, many companies and institutions decide to build and maintain own wide area networks (WAN) for ensuring reliable and secure distributed processing of data. Design of WANs in concerned with solving different optimization problems, like routing assignment, capacities of channel selection, resource (i.e. servers, management centre) allocation. Due to peculiar structure of wide area networks and nature of protocols, proper optimization methods and algorithms should be constructed for WAN-based distributed computing systems. In the paper the model of the distributed environment, built on WAN infrastructure is presented. Then, the optimization problem for routing assignment, channel capacities assignment and grid management center (data repository) allocation is formulated. Finally, an approximate algorithm is presented for formulated problem. Proposed algorithm, observations and conclusions should effect in improving of distributed computing systems design.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 2; 197-202
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Permutation, no-wait, no-idle flow shop problems
Autorzy:
Makuchowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/229973.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flow shop problem
permutation constraint
no-wait constraint
no-idle constraint
permutation-graph models
Opis:
The paper compares the schedules of different variants of the flow shop problem, i.e. permutation, no waiting and no idle flow shop problems. It is assessed the impact of the constraints on the extension of the schedules and correlations of the length of the schedules for these variants. It is also examined the effectiveness of a set of insert type algorithms. The efficiency of the algorithms is tested on well-known literature benchmarks.
Źródło:
Archives of Control Sciences; 2015, 25, 2; 189-199
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vortex in cell method for exterior problems
Metoda cząstek wirowych dla zagadnień zewnętrznych
Autorzy:
Kudela, H.
Kozłowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/279735.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
vortex method
flow past cylinder
external problem
Opis:
The ”vortex in cell” method was used to model the flow past a solid body. Problems connected with flows past a body belong to the category of exterior problems. The main difficulty here is to establish the boundary condition far from the body, to solve equations of motion on the numerical mesh. The mesh requires a limited calculation area and the boundary condition far from the body. A method of obtaining the accurate boundary condition in such flows was presented. Testing calculations were performed for the flow past a cylinder for a wide range of Reynolds numbers. The flow past an ellipse was also performed. A good agreement with experimental results and calculations of other researchers was obtained.
Do obliczeń zastosowano metodę cząstek wirowych typu „wir w komórce”. Rzeczywisty obszar przepływu transformowano używając odwzorowania konforemnego. Opisano sposób wyznaczania zewnętrznego warunku brzegowego daleko od ciała, wykorzystując asymptotyczne własności rozwiązania równania Laplace’a. Wyniki numeryczne przedstawiono dla opływu walca w szerokim przedziale liczb Reynoldsa (550 < Re > 9500) oraz cienkiej elipsy. Obliczenia porównano z danymi eksperymentalnymi i wynikami numerycznymi innych badaczy, uzyskując bardzo dobrą zgodność.
Źródło:
Journal of Theoretical and Applied Mechanics; 2009, 47, 4; 779-796
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of flow rate in square-sectioned duct bend
Pomiar strumienia płynu w kanale z łukiem kolana o przekroju kwadratowym
Autorzy:
Rup, K.
Malinowski, Ł.
Sarna, P.
Powiązania:
https://bibliotekanauki.pl/articles/280883.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
measurement of flow rate
inverse coefficient problem
Opis:
In this paper the authors describe an attempt to utilise installed square- sectioned elbows in order to measure the fluid flow rate. In order to practically accomplish the measurement of the volumetric flow rate of the air, a special research stand has been built, and square shaped elbows have been installed (80 × 80mm in dimension). The numerical computations were carried out using the software package FLUENT 6.2. The obtained results were compared to corresponding ones coming from orifice measurements and from experimental work available in the literature. The comparative analysis of the obtained numerical and experimental results evidenced a high degree of their conformity.
W pracy podjęto próbę wykorzystania zainstalowanych w kanałach przepływowych łuków kolan o przekroju kwadratowym do pomiaru strumienia objętości płynu. W tym celu wykorzystano opracowaną wcześniej metodę pomiaru pośredniego dla rurociągów o przekroju kołowym. Dla praktycznej realizacji pomiaru wspomnianego strumienia przepływu zbudowano stanowisko badawcze za łukiem kolana o przekroju poprzecznym w kształcie kwadratu (80 × 80mm). Obliczenia wykonano za pomocą pakietu FLUENT 6.2. Uzyskane rezultaty porównano z odpowiednimi zmierzonymi za pomocą kryzy pomiarowej oraz z innymi wynikami doświadczalnymi dostępnymi w literaturze. Z analizy porównawczej wynika wysoki stopień zgodności otrzymanych rezultatów pomiaru pośredniego.
Źródło:
Journal of Theoretical and Applied Mechanics; 2011, 49, 2; 301-311
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model to calculate the optimal mode of train locomotives turnover
Autorzy:
Kozlov, P.
Vakulenko, S.
Tushin, U.
Timukhina, E.
Powiązania:
https://bibliotekanauki.pl/articles/374643.pdf
Data publikacji:
2017
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
model
locomotive
train flow
optimization
transportation problem
lokomotywa
natężenie ruchu kolejowego
optymalizacja
problem transportowy
Opis:
A model to calculate the optimal work modes of train locomotives while serving train flows is proposed. The model is a further development of the dynamic transportation problem. Parameters of train movement and locomotive utilization are published. Both locomotive turnover and train schedules are produced. Useful utilization of locomotives increases from 70% to 90–95%. This allows the reduction of several thousands of train locomotives.
Źródło:
Transport Problems; 2017, 12, 3; 125-133
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fuzzy project scheduling using constraint programming
Autorzy:
Relich, M.
Powiązania:
https://bibliotekanauki.pl/articles/118137.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
project cash flow
constraint satisfaction problem (CSP)
project portfolio
Opis:
The paper aims to present an application of constraint programming techniques for project portfolio scheduling taking into account the imprecision in activity duration and cost. Data specification in the form of discrete a-cuts allows combining distinct and imprecise data, and implementing a constraint satisfaction problem with the use of constraint programming. Moreover using a-cuts, optimistic, pessimistic, and several intermediate scenarios concerning the project scheduling and cash flows can be obtained and considered in terms of different risk levels.
Źródło:
Applied Computer Science; 2013, 9, 1; 3-16
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Homotopy perturbation method combined with Trefftz method in numerical identification of liquid temperature in flow boiling
Autorzy:
Hożejowska, S.
Powiązania:
https://bibliotekanauki.pl/articles/281648.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
homotopy perturbation method
Trefftz method
flow boiling
inverse problem
Opis:
The paper is focused on numerical identification of 2D temperature fields in flow boiling of the liquid through a horizontal minichannel with a rectangular cross-section. The heat transfer process in the minichannel is described by a two-dimensional energy equation with the corresponding boundary conditions. Liquid temperature is determined using the homotopy perturbation method (HPM) with Trefftz functions for Laplace’a equation. The numerical solution to the energy equation found with the HPM is compared with the solution obtained for the simplified form of the energy equation. Considering that only the thermal sublayer is taken into account, both solutions give similar results.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 969-980
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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