Wyniki wyszukiwania - Biblioteka Nauki

1

Price-based coordinability in hierarchical systems with information asymmetry: a comparative analysis of Nash equilibrium conditions

100%

Karpowicz M. P. , Malinowski K.

Control and Cybernetics

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2013

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tom Vol. 42, no. 1

85--110

EN

The well-known problem of price-based coordinability is studied for the case of a multi-agent system in which information regarding the goals of the interacting subsystems is asymmetric. The paper illustrates how the uniform-price-based coordination rulet may create incentives to anticipate the values of coordination signals and, thus, why the coordinability condition cannot be satisfied under asymmetric information. For this purpose a comparison is given of Nash equilibrium outcomes that are reachable individually by priceanticipating agents in two noncooperative games. These games are induced by the uniform-price-based coordination mechanism and are referred to as payment-bidding auction and demand-bidding auction. The analysis presented shows that in the games considered some of the agents may improve payoffs and allocations by applying the price-anticipating bidding strategies. However, the payment-bidding auction cannot be strictly dominated by the demand-bidding action with respect to the resource allocation levels individually received by each agent. The derived results of theoretic considerations are illustrated by numerical examples.

2

A Practical Course for Teaching Fundamental Optimization Techniques in Electrical Engineering

100%

Brauer H. , Kuilekov M.

Przegląd Elektrotechniczny

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2003

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tom R. 79, nr 10

690-692

EN

The paper presents a new toolbox containing a wide range of optimization methods to be used by students in undergraduate studies of electrical engineering. Both deterministic and stochastic optimization techniques can be applied to a large set of known test functions. The computer laboratory course is used since one year to secure student´s knowledge of optimization and solving of inverse field problems given in the pertinent lectures.

3

Optimisation of composite shapes with the help of genetic algorithms

100%

Hufenbach W. , Gude M. , Kroll L. , Kostka P. , Sokołowski A.

Computer Assisted Mechanics and Engineering Sciences

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2005

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tom Vol. 12, No. 2-3

163-173

EN

During the manufacturing process of multilayered fibre-reinforced composites with variable fibre orientations, residual stresses build up due to the directional expansion of the single unidirectionally reinforced layers. Dependent on the laminate lay-up, these inhomogeneous residual stresses, which are caused by thermal effects, moisture absorption and chemical shrinkage, can lead to large multistable out-of-plane deformations. Instead of avoiding these laminate's curvatures, they can be advantageously used for technical applications following the near-net-shape technology. However, due to the effect that the laminate curvature depends on huge amount of different parameters such as anisotropic, hygroscopic and thermomechanical material properties, fibre orientations and ply thickness of each single layer as well as technological processing parameters, a search in a multi-dimensional search area is necessary. In order to solve such a task, Genetic Algorithms in combination with a fitness function based on a nonlinear semi-analytical calculation model for the laminate shape prediction have been applied and described in the paper. Using this approach, one can purposefully adapt the laminate lay-up dependent on the loading and process parameters.

4

Effect of tripping velocity profiles on wellbore pressures and dynamic loading of drillstring

100%

Wang Z. , Miska S. , Yu M. , Takach N.

AGH Drilling, Oil, Gas

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2013

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tom Vol. 30, no. 1

269--286

EN

Tripping events are expensive and time-consuming. Thus, minimizing tripping time through choosing optimized tripping velocity becomes urgent. Surge or swab pressures in the wellbore and dynamic loading of drillstring will be generated during tripping. Also, dynamic velocity, which is the velocity at the bottom of drillstring, is different from the input velocity at surface. The effect of tripping velocity profile, i.e., tripping velocity changes with time, on the hook load, downhole pressure changes and drillstring dynamic velocity should be fully studied to achieve the optimization. In this study, the effects of tripping velocity profile on loading of drillstring, dynamic velocity and downhole pressure is investigated using numerical simulation. Bergeron's graphical method and Lubinski's approach are utilized to perform the simulations. Components of drillstring, wellbore depth, drillstring length and mud properties are also included in the simulations. Through the current work, a driller's typical way of changing tripping velocity may not be the best one. Selection of tripping velocity profiles should be adapted to depth: higher velocity, triangular/parabolic profiles in shallow wells and lower velocity, trapezoidal profiles in deep wells. Also, based on simulations, the oscillation magnitude of dynamic velocity can be as high as twice that of velocity at surface.

5

Multiobjective optimization of reflector’s shape

100%

Wandachowicz K.

Computer Applications in Electrical Engineering

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2013

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tom Vol. 11

370--379

EN

The article presents results of research on the calculation of the shape of a mirror reflector, which ensures the highest possible average illuminance, and uniformity of illuminance. A multiobjective genetic algorithm was used to carry out optimization calculations.

6

Metody i modele optymalizacyjne w logistyce

100%

Winiczenko R.

Gospodarka Materiałowa i Logistyka

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2010

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tom nr 1

30-32

PL

Podejmowanie w logistyce wielu trudnych decyzji o charakterze ilościowym stanowi proces przetwarzania informacji wymagający stosowania badań operacyjnych. Możliwość praktycznego wykorzystania badań operacyjnych umożliwiają komputery oraz ich odpowiednie oprogramowanie, które opracowano na bazie odpowiednich metod i modeli optymalizacyjnych. Do najważniejszych modeli stosowanych we współczesnej logistyce należą modele optymalizacyjne, symulacyjne i heurystyczne.

EN

In the article the general rule of functioning of chosen optimization, simulation and heuristic methods and models was presented. These tools are very useful in nowadays logistics, various industrial branches and material management.

7

Optimization of a two-phase transverse flux switched reluctance motor with an outer rotor

80%

Łukaniszyn M. , Kowol M. , Kołodziej J.

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8

Learning the naive Bayes classifier with optimization models

80%

Taheri S. , Mammadov M.

International Journal of Applied Mathematics and Computer Science

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2013

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tom 23

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nr 4

787-795

EN

Naive Bayes is among the simplest probabilistic classifiers. It often performs surprisingly well in many real world applications, despite the strong assumption that all features are conditionally independent given the class. In the learning process of this classifier with the known structure, class probabilities and conditional probabilities are calculated using training data, and then values of these probabilities are used to classify new observations. In this paper, we introduce three novel optimization models for the naive Bayes classifier where both class probabilities and conditional probabilities are considered as variables. The values of these variables are found by solving the corresponding optimization problems. Numerical experiments are conducted on several real world binary classification data sets, where continuous features are discretized by applying three different methods. The performances of these models are compared with the naive Bayes classifier, tree augmented naive Bayes, the SVM, C4.5 and the nearest neighbor classifier. The obtained results demonstrate that the proposed models can significantly improve the performance of the naive Bayes classifier, yet at the same time maintain its simple structure.

9

Optimization of electrocoagulation of instant coffee production wastewater using the response surface methodology

80%

Bui H. M.

Polish Journal of Chemical Technology

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2017

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tom Vol. 19, nr 2

67--71

EN

The COD removal efficiency from an instant coffee processing wastewater using electrocoagulation was investigated. For this purpose, the response surface methodology was employed, using central composing design to optimize three of the most important operating variables, i.e., electrolysis time, current density and initial pH. The results based upon statistical analysis showed that the quadratic models for COD removal were significant at very low probability value (<0.0001) and high coefficient of determination (R2 = 0.9621) value. The statistical results also indicated that all the three variables and the interaction between initial pH and electrolysis time were significant on COD abatement. The maximum predicted COD removal using the response function reached 93.3% with electrolysis time of 10 min, current density of 108.3 A/m2 and initial pH of 7.0, respectively. The removal efficiency value was agreed well with the experimental value of COD removal (90.4%) under the optimum conditions.

10

Closed Loop Supply Chain with Production Planning

80%

Stecz W.

Research in Logistics & Production

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2016

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tom Vol. 6, No. 2

117--128

EN

We present a Closed Loop Supply Chain (CLSC) model that supports a production planning (PP) process. CLSC model is based on CLSC framework model which consists of four main centers: collection, recovery center, distribution and disposal centers. These logistics parts support main production lines. Some quantity of the products is recovered and the factories don’t need to spend money for production. This is a simple cost reduction process. In CLSC literature one can hardly meet the models of production planning processes supported by CLSC. Important problem with that models is the computational complexity when one wants to prepare production plans for more than one time period. This is connected with a number of the numerical variables of the CLSC and PP models which are usually Integer Programming models solved with Branch & Bound algorithms. We present some modifications of the widely known and used constraints in the CLSC models to optimize solving process. All the experiments were conducted with the CPLEX solver.

11

A novel approach for power system stabilizer control parameter selection: a case-study on two-area four-machine system

80%

Gude M. K. , Salma U.

Archives of Electrical Engineering

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2022

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tom Vol. 71, nr 2

297--407

EN

This paper proposes a power system stabilizer (PSS) with optimal controller parameters for damping low-frequency power oscillations in the power system. A novel meta-heuristic, weighted grey wolf optimizer (GWO) has been proposed, it is a variant of the grey wolf optimizer (GWO). The proposed WGWO algorithm has been executed in the selection of controller parameters of a PSS in a multi-area power system. A two-area four- machine test system has been considered for the performance evaluation of an optimally tuned PSS. A multi-objective function based on system eigenvalues has been minimized for obtained optimal controller parameters. The damping characteristics and eigenvalue location in the proposed approach have been compared with the other state-of-the-art- methods, which illustrates the effectiveness of the proposed approach.

12

Procedure application in assembler encoding

80%

Praczyk T.

Archives of Control Sciences

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2007

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tom Vol. 17, no. 1

71-91

EN

In order to use evolutionary techniques to search for optimal neural networks it is necessary to encode the latter in the form of chromosome or a set of chromosomes. In the paper a new neural network encoding method is presented - assembler encoding (AE). It assumes neural network encoded in the form of linearly organized structure similar to assembler program with code part and with data part. The task of assembler code is to create connectivity matrix which in turn can be transferred into neural network with any architecture. In the article the variant of AE in which we deal with application of procedures is discussed. Assembler encoding programs consisting of many procedures are used to solve optimization problem. Results of tests conducted are included in the paper.

13

An enhanced krill herd optimization technique used for classification problem

80%

Al-Mashhadani F. N. , Alsaffar Q. S. , Al-Jadir I. A.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2021

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tom Vol. 30, No. 2

354--364

EN

In this paper, this method is intended to improve the optimization of the classification problem in machine learning. The EKH as a global search optimization method, it allocates the best representation of the solution (krill individual) whereas it uses the simulated annealing (SA) to modify the generated krill individuals (each individual represents a set of bits). The test results showed that the KH outperformed other methods using the external and internal evaluation measures.

14

Placement over containers with fixed dimensions solved with adaptive neighborhood simulated annealing

80%

Martins T. C. , Tsuzuki M. S. G.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2009

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tom Vol. 57, nr 3

273-280

EN

This work deals with the problem of minimizing the waste of space that occurs on a rotational placement of a set of irregular bi-dimensional items inside a bi-dimensional container. This problem is approached with a heuristic based on Simulated Annealing (SA) with adaptive neighborhood. The objective function is evaluated in a constructive approach, where (he items are placed sequentially. The placement is governed by three different types of parameters: sequence of placement, the rotation angle and the translation. The rotation applied and the translation of the polygon are cyclic continuous parameters, and the sequence of placement defines a combinatorial problem. This way, it is necessary to control cyclic continuous and discrete parameters. The approaches described in the literature deal with only type of parameter (sequence of placement or translation). In the proposed SA algorithm, the sensibility of each continuous parameter is evaluated at each iteration increasing the number of accepted solutions. The sensibility of each parameter is associated to its probability distribution in the definition of the next candidate.

15

A design of DSS for mass production machining systems

80%

Dolgui A. , Guschinsky N. , Levin G.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2009

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tom Vol. 57, nr 3

265-271

EN

In this paper, we present a decision support tool (DSS) for preliminary design of transfer machines with rotary or mobile tables. In these transfer machines, the machining operations are executed on working positions equipped by standard multi-spindle heads. A part is sequentially machined on m working positions and is moved from one position to the next using a rotary or a mobile table. The operations are grouped into blocks, where the operations of the same block are simultaneously performed by one multi-spindle head. At the preliminary design stage, the goal is to select the number of working positions and to decide which spindle heads will be installed minimizing the machine cost while respecting a given production rate. The paper presents the overall approach and depicts mathematical and decision-support methods developed and implemented in a software for the optimization of preliminary design (or reconfiguration) of such machining systems.

16

Turbomachinery component design by means of CFD

80%

Braembussche R. A. v. d.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2002

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tom Vol. 6, No 1

39-61

EN

A short overview of the main techniques for turbomachinery blade design based on CFD is followed by a more detailed description on an Optimisation- and Inverse Design method, developed at the von Karman Institute. The optimisation method uses an Artificial Neural Network to extract knowledge from a Database containing the results of previous designs and a Genetic Algorithm to define the optimum blade. The inverse design method makes use of the Euler or Navier-Stokes equations to predict how a given 3D blade shape should be modified to reach a prescribed pressure or Mach number distribution along the blade surface. Examples of transonic compressor and turbine blades, designed by both methods, illustrate the potential of these modern aero-design systems. Special attention is given to the problems related to existence and uniqueness and to those features that facilitate the practical use of these methods.

17

Ecological model of Virus-Evolutionary Genetic Algorithm

80%

Kubota N. , Fukuda T.

Fundamenta Informaticae

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1999

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tom Vol. 37, Nr 1,2

51-70

EN

This paper deals with an ecological model on planer gird of a genetic algorithm based on vi-rus theory of evolution (E-VE-GA). In the E-VE-GA, each individual is placed on a planer grid and genetic operators are performed between neighborhoods. The E-VE-GA can self-adaptively change searching ratio between global and local searches. The main operator of the E-VE-GA is reserve transcription and incorporation transmitting local genetic information. The convergence of the E-VE-GA depends on the frequency and localization of the virus in-fection. In this paper, we apply the E-VA-GA to traveling salesman problems and discuss the coevolution of host and virus populations through the numerical simulation.

18

A Method to Improve Planning of Product Placement on a Printing Sheet

80%

Czerniachowska K. , Żywicki K. , Wichniarek R.

Management and Production Engineering Review

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2021

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tom Vol. 12, No. 1

119--128

EN

Major manufactures are moving towards a sustainability goal. This paper introduces the results of collaboration with the leading company in the packaging and advertising industry in Germany and Poland. The problem addresses the manufacturing planning problem in terms of minimizing the total cost of production. The challenge was to bring a new production planning method into cardboard manufacturing and paper processing which minimizes waste, improves the return of expenses, and automates daily processes heavily dependent on the production planners’ experience. The authors developed a module that minimizes the total cost, which reduces the overproduction and is used by the company’s manufacturing planning team. The proposed approach incorporates planning allowances rules to compromise the manufacturing requirements and production cost minimization.

19

Research on a method of hull form design based on wave-making resistance optimization

80%

Jianglong Sun J. , Xujian Lv X. , Weibin Liu W. , Hanwen Ning H. , Xianwen Chen X.

Polish Maritime Research

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2012

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tom nr 3

16-25

EN

In this paper, we consider an optimization of the hull shape in order to minimize the total resistance of a ship. The total resistance is assumed to be the sum of the wave resistance computed on the basis of the thin-ship theory and the frictional resistance. Smoothness of hull lines is proved with mathematical procedure, in which differentials of the hull lines functions are analyzed. The wave-making resistance optimization, involving a genetic algorithm, uses Michell integral to calculate wave resistance. A certain hull form is generated by the method using cross section information of a modified DTMB model ship 5415 and a comparative experiment is carried out. Experimental and calculation result show that the method is of good adaptability for designing certain types of ships with excellent resistance performance.

20

Optymalizacja dynamiczna napędu pneumatycznego

80%

Tarnowski W. , Kiczkowiak T.

Pneumatyka

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2008

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tom nr 1

78-81

PL

Uzasadniono potrzebę jednoczesnej optymalizacji konstrukcji obiektu i jego sterowania. Na przykładzie napędu pneumatycznego pokazano taką możliwość, po dyskrety-zacji funkcji sterowania. Przeprowadzono polioptymalizacje ze względu na dwa kryteria: czas wykonania przesunięcia i prędkość układu ruchomego po osiągnięciu punktu końcowego.

EN

It is shown that a control function and design parameters of an object should and may be optimized in one optimization task. An example of a pneumatic drive is used. Discretization of the control signal is adopted, and polyoptimization is completed on two criteria: the time of a full stroke and the final velocity of the drive.