Browsing by Subject "sensitivity analysis"

Now showing 1 - 7 of 7

Access status: Open Access ,
A dedicated sensitivity analysis and optimization application for industrial processes
(Wydawnictwa AGH, 2021) Myczkowska, Kamila; Szeliga, Danuta
The paper describes the architecture and the use case of the developed Modelbox system for sensitivity analysis (SA), uncertainty analysis (UA) and the subsequent optimization of industrial processes. The proposed solution addresses the most common practical and technical problems encountered by researchers and engineers when performing sensitivity analysis. It combines the functions from the numerical toolbox with a simulation management system. Maintaining usability and a good user experience while managing complex investigations of time-consuming industrial process simulations is a very important feature of the system. Several improvements were introduced to optimize the computation time of analysis/modelling tasks, including the automatization of distributed calculations, persistent, transparent caching of simulation data and duration estimations from collected statistics. The system has the ability to perform remote, parallel, asynchronous computations of both analytic algorithms and numerical simulations. The system is dynamically scalable horizontally by using serverless computing endpoints and thus it can be easily adapted to the user's current needs in a flexible way. Modelbox provides web-based access to analysis/modelling tasks from sampling, SA/UA, optimization to metamodelling. It is extended with numerous interactive visualization components for effective results control. In addition, to access data from the completed analysis, the system supports convergence tracking for SA estimates and intermediate optimization results. The process of controlled cooling of rails was considered as a case study. The formulated optimization task was to find a combination of process parameters that ensures a minimum volume fraction of bainite along with required interlamellar spacing and optimal homogeneity of hardness. Different sensitivity analysis methods were used to evaluate the significance of all variables with respect to their influence on the model output.
Access status: Restricted ,
Analiza zastosowań metody zbiorów losowych do wybranych zagadnień inżynierskich
(Data obrony: 2018-09-27) Ślipek, Monika
Wydział Geologii, Geofizyki i Ochrony Środowiska
Zamierzeniem niniejszej pracy była analiza zastosowań metody zbiorów losowych do wybranych zagadnień inżynierskich. W tym celu posłużono się numerycznym modelem eksperymentalnego wału przeciwpowodziowego. Metoda zbiorów losowych wymaga dużej ilości obliczeń, dlatego w celu zredukowania tej liczby wykorzystano dwie metody analizy wrażliwości: Random Set Distinct Element Method oraz metodę Morris Screening, dzięki którym można określić istotność wpływu danego parametru na wyniki wyjściowe. Dzięki temu zredukowano liczbę parametrów wejściowych oraz wykonano modelowania dla ciśnienia porowego wału przeciwpowodziowego metodą zbiorów losowych. W pracy pokazano przykład zagadnień inżynierskich do których możliwe jest zastosowanie metody zbiorów losowych. Częściowe wyniki pracy zostały opublikowane i przedstawione na międzynarodowej konferencji 18th International Multidisciplinary Scientific GeoConference SGEM 2018.
Access status: Open Access ,
Postoptimal analysis in the coefficients matrix of piecewise linear fractional programming problems with non-degenerate optimal solution
(2010) Kheirfam, Behrouz
In this paper, we discuss how changes in the coefficients matrix of piecewise linear fractional programming problems affect the non-degenerate optimal solution. We consider separate cases when changes occur in the coefficients of the basic and non-basic variables and derive bounds for each perturbation, while the optimal solution is invariant. We explain that this analysis is a generalization of the sensitivity analysis for $LP$, $LFP$ and $PLP$. Finally, the results are described by some numerical examples.
Access status: Open Access ,
Ryzyko inwestycyjne i eksploatacyjne w przemyśle wytwarzania energii elektrycznej
(2011) Michalski, Marek Ł.
W opracowaniu przedstawiono wady i zalety poszczególnych metod uwzględnienia i oceny ryzyka oraz ich zastosowania w wyborze inwestycji w przemyśle wytwarzania energii elektrycznej. W tym zakresie ocenie poddano zastosowanie podwyższonej stopy dyskontowej, analizę wrażliwości i scenariuszy, symulację Monte Carlo oraz drzewa decyzyjne i opcje realne.
Access status: Open Access ,
Sensitivity analysis in piecewise linear fractional programming problem with non-degenerate optimal solution
(2009) Kheirfam, Behrouz
In this paper, we study how changes in the coefficients of objective function and the right-hand-side vector of constraints of the piecewise linear fractional programming problems affect the non-degenerate optimal solution. We consider separate cases when changes occur in different parts of the problem and derive bounds for each perturbation, while the optimal solution is invariant. We explain that this analysis is a generalization of the sensitivity analysis for $LP$, $LFP$ and $PLP$. Finally, the results are described by some numerical examples.
Access status: Open Access ,
Weight Impact on Comparative Evaluation of Topographic Data
(Wydawnictwa AGH, 2024) Borkowska, Sylwia; Bielecka, Elżbieta; Pokonieczny, Krzysztof
The paper addresses the problem of weighting in an analysis that supports the selection of a categorical data set according to user needs. Using the Relative Change (RC) of the Compound Correspondence Index (CCI), it is shown that weights have a significant impact on user choice – reaching extreme values in both urbanized and forested areas. Decreasing the weights from 0.25 to 0.17 in forested and built-up areas resulted in the maximum variations that were seen in the hot spot maps, with cold areas generally corresponding to built-up regions and hot areas to forested areas. The analysis covers seven counties that are located in different regions of Poland: Pomerania, Podlasie, Mazovia, Greater Poland and the Beskidy Mountains.
Access status: Open Access ,
Zastosowanie metody zbiorów losowych do obliczeń tunelu budowlanego nową metodą austriacką (NATM)
(Wydawnictwa AGH, 2005) Sysik, Paweł; Siemińska-Lewandowska, Anna
In the article a method of capturing uncertainty in geotechnical engineering based on random sets' theory was proposed. This approach allows for assignation of probability masses to sets or intervals. Assumption regarding probability distribution is not required. Information about soil parameters from different sources appearing as intervals can be used. Practical application was demonstrated by means of tunnel excavation problem. The runnel was excavated according to the principles of New Austrian Tunneling Method (NATM). In the analysis deformation of tunnel lining was investigated. As a result ranges of displacements were obtained. This showed possible behavior of the structure. One of calculation steps was sensitivity analysis. On its basis soil parameters which have the biggest influence on displacements were identified. Only these parameters were used as variables in further analysis. Thus computational effort was reduced significantly.