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Wyszukujesz frazę "a* algorithm" wg kryterium: Temat


Tytuł:
Multi-variable optimization of an ytterbium-doped fiber laser using genetic algorithm
Autorzy:
Hashemi, S. S.
Ghavami, S. S.
Khorsandi, A
Powiązania:
https://bibliotekanauki.pl/articles/175086.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber laser
optimization
genetic algorithm
Opis:
We introduce the genetic algorithm for the optimization of an Yb3+-doped double-clad fiber laser based on a multi-variable scheme. The output characteristic of the laser is numerically simulated using real practical values. This is performed through solving the associated steady-state rate equation and investigating the effects of input variables such as pump and signal wavelengths and length of the fiber on the laser output. It is found that pumping of the medium around 975 nm is conducted to attain the maximum output power of ~34.8 W, while the stability of the outcoupled power is significantly improved when pumping at 920 nm, confirming good agreement with the reported experimental results. We have also found that by using genetic algorithm base multi-variable optimization, the output power can be significantly increased by about three orders of magnitude and reaches to ~28.5 W with optimum and shorter fiber length of ~57.5 m. Obtained results show that based on the genetic algorithm multi-variable discipline, fiber characteristics can be optimized according to the gaining of maximum output power.
Źródło:
Optica Applicata; 2015, 45, 3; 355-367
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simulator supporting the distribution of the primary subsidy in a faculty at Wroclaw University of Technology
Autorzy:
Rekuć, W.
Szczurowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/406255.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
algorithm for subsidy distribution
simulator
Opis:
Chosen aspects of a simulator supporting the distribution of the primary teaching subsidy in a faculty of Wroclaw University of Technology have been presented. The mathematical equations forming the basis for the algorithm have been analyzed. The general premises of adapting the set of teaching duties within a faculty to this model have been formulated. Various scenarios illustrating how the distribution of this subsidy works in practice have been shown. Introductory results of such simulations (using MS EXCEL) for a chosen scenario have been presented and discussed.
Źródło:
Operations Research and Decisions; 2015, 25, 4; 35-49
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Management and decisions in the structures of human activities
Autorzy:
Galanc, T.
Kołwzan, W.
Pieronek, J.
Skowronek-Grądziel, A.
Powiązania:
https://bibliotekanauki.pl/articles/406575.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
management
decision-making
structure
algorithm
scientific language
Opis:
This article has been devoted to the key dimensions of decision-making. The main goal of the authors was to point out the role and effect of invariants of nature, logic and conceptual systems of science and management, which are extremely important in decision-making processes. The research hypothesis has been tested that the complexity of decision-making and management are determined by the state of reality (Nature). This hypothesis is related to the fact that in science there is currently no uniform methodology associated with decision-making, just as science is not methodologically uniform. One can even doubt whether it is possible to describe the essential dimensions of decisions undertaken by Man, as discussed in this article. These problems are not a novelty to science, since they have been analysed by many scientists in the past. The authors of the article present the complexity and diversity of concepts defining systems of decision-making and management, based on selected fields of knowledge which are generally relevant to this issue, in particular fields associated with ontology and epistemology. Therefore, the text refers broadly to investigating the reality of basic areas of human knowledge and the overlapping relationships between them. This applies to the so-called circle of the sciences proposed and examined by the psychologist J. Piaget. An additional aim of the authors was to create a text presenting contemporary human knowledge about the reality which surrounds us. To understand reality means to be in relative equilibrium with it.
Źródło:
Operations Research and Decisions; 2017, 27, 4; 45-69
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on visible light indoor positioning algorithm based on fire safety
Autorzy:
Li, Mao
Jiang, Feng
Pei, Cong
Powiązania:
https://bibliotekanauki.pl/articles/174338.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
indoor positioning algorithm
camera
indoor positioning system
Opis:
From the perspective of ensuring life safety, combined with the advantages of high-speed time response and energy conservation of white light emitting diodes (LEDs), the visible light indoor positioning algorithm based on fire safety is proposed in the paper. First, the model is designed which needs three LED lights arranged in a straight line and positioned in the geographically north direction on the top of the model. Then, the proposed algorithm is discussed and analyzed when the camera is located at the center of the model and facing north, when the camera is located at the center of the model and the angle is rotated, and when the camera is located at any position of the model, respectively. It can accurately calculate the current position of the camera, its response speed is fast and the positioning accuracy is high. Furthermore, this paper also verifies the practicability and reliability of the algorithm by designing the visible light indoor positioning system based on fire safety rescue in natural environment and smoke environment. The experimental results show that the positioning error does not exceed 0.70 cm in smoke environment.
Źródło:
Optica Applicata; 2020, 50, 2; 209-222
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth extraction in computational integral imaging based on bilinear interpolation
Autorzy:
Huang, Huihua
Ge, Peng
Powiązania:
https://bibliotekanauki.pl/articles/1835812.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
computational integral imaging
depth extraction
bilinear interpolation algorithm
Opis:
We proposed a method using a merit function to determine the depth of objects in computational integral imaging by analyzing the existing methods for depth extraction of target objects. To improve the resolution of reconstructed slice images, we use a digital camera moving in horizontal and vertical direction with the set interval to get elemental images with high resolution and bilinear interpolation algorithm to increase the number of pixels in slice image which improves the resolution obviously. To show the feasibility of the proposed method, we carried out our experiment and presented the results. We also compared it with other merit functions. The results show that merit function SMD2 to determine the depth of objects is more accurate and suitable for real-time application.
Źródło:
Optica Applicata; 2020, 50, 4; 497-509
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stochastic programming model for production planning with stochastic aggregate demand and spreadsheet-based solution heuristics
Autorzy:
Saadouli, Nasreddine
Powiązania:
https://bibliotekanauki.pl/articles/2100358.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
production planning
stochastic programming
efficient algorithm
decision-making
Opis:
By discretising the stochastic demand, a deterministic nonlinear programming formulation is developed. Then, a hybrid simulation-optimisation heuristic that capitalises on the nature of the problem is designed. The outcome is an evaluation problem that is efficiently solved using a spreadsheet model. The main contribution of the paper is providing production managers with a tractable formulation of the production planning problem in a stochastic environment and an efficient solution scheme. A key benefit of this approach is that it provides quick near-optimal solutions without requiring in-depth knowledge or significant investments in optimisation techniques and software.
Źródło:
Operations Research and Decisions; 2021, 31, 4; 117--127
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improving estimation accuracy of metallurgical performance of industrial flotation process by using hybrid genetic algorithm – artificial neural network (GA-ANN)
Autorzy:
Allahkarami, E.
Salmani Nuri, O.
Abdollahzadeh, A.
Rezai, B.
Maghsoudi, B.
Powiązania:
https://bibliotekanauki.pl/articles/109424.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
artificial neural network
genetic algorithm
prediction
copper flotation
Opis:
In this study, a back propagation feed forward neural network, with two hidden layers (10:10:10:4), was applied to predict Cu grade and recovery in industrial flotation plant based on pH, chemical reagents dosage, size percentage of feed passing 75 μm, moisture content in feed, solid ratio, and grade of copper, molybdenum, and iron in feed. Modeling is performed basing on 92 data sets under different operating conditions. A back propagation training was carried out with initial weights randomly mode that may lead to trapping artificial neural network (ANN) into the local minima and converging slowly. So, the genetic algorithm (GA) is combined with ANN for improving the performance of the ANN by optimizing the initial weights of ANN. The results reveal that the GA-ANN model outperforms ANN model for predicting of the metallurgical performance. The hybrid GA-ANN based prediction method, as used in this paper, can be further employed as a reliable and accurate method, in the metallurgical performance prediction.
Źródło:
Physicochemical Problems of Mineral Processing; 2017, 53, 1; 366-378
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fully-phase optical image encryption in diffractive-imaging scheme with QR-code-based random illumination
Autorzy:
Wang, Z.
Zhang, Y.
Gong, Q.
Li, S.
Qin, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174126.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical encryption
diffractive imaging
fully phase
phase retrieval algorithm
Opis:
Based on a fully phase encoding and phase retrieval algorithm, a diffractive-imaging-based optical encryption scheme with random illumination is proposed. In the encryption process, a QR code image is placed in the optic path to modulate the incident light and thus generate a random illumination, which has been demonstrated to enable the proposed scheme to resist the multi-slice ptychographic phase retrieval algorithm attack. The plaintext is phase-encoded, and then encrypted by two random phase masks. The diffraction pattern in the output plane is recorded as ciphertext by a CCD camera. For decryption, an iterative phase retrieval algorithm with median filtering operation is implemented. Simulation results demonstrate the effectiveness, security, and robustness of the proposal.
Źródło:
Optica Applicata; 2017, 47, 2; 233-243
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of sensorless control of permanent magnet synchronous generator in wind turbine system
Autorzy:
Gajewski, P.
Pieńkowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193265.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wind turbine
PMSG
power converters
sensorless algorithm
simulation studies
Opis:
The paper presents a sensorless control of permanent magnet synchronous generator (PMSG) in a variable-speed wind energy conversion system. The system of wind turbine consists of PMSG and back-to-back power converter. The back-to-back converter system is composed of machine side converter (MSC) and grid side converter (GSC). In the control of MSC and GSC the methods of vector control have been applied. For operation of MSC the method of Rotor Field Oriented Control (RFOC) with MPPT algorithm has been used. For estimation of angular rotor position and angular speed the flux linkage estimator with synchronous frame phase locked loop (SF-PLL) has been used. In the control of GSC the method of Voltage Oriented Control (VOC) has been considered. Simulation studies have been carried out in order to evaluate the system of sensorless strategy. The results of simulation studies demonstrate the high efficiency and high accuracy of the sensorless control system considered.
Źródło:
Power Electronics and Drives; 2016, 1, 36/2; 165-174
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining models of influence
Autorzy:
Grabisch, M.
Rusinowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/406296.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
social network
opinion formation
aggregation function
influential coalition
algorithm
Opis:
We consider a model of opinion formation based on aggregation functions. Each player modifies his opinion by arbitrarily aggregating the current opinion of all players. A player is influential on another player if the opinion of the first one matters to the latter. Generalization of an influential player to a coalition whose opinion matters to a player is called an influential coalition. Influential players (coalitions) can be graphically represented by the graph (hypergraph) of influence, and convergence analysis is based on properties of the hypergraphs of influence. In the paper, we focus on the practical issues of applicability of the model w.r.t. a standard framework for opinion formation driven by Markov chain theory. For a qualitative analysis of convergence, knowing the aggregation functions of the players is not required, one only needs to know the set of influential coalitions for each player. We propose simple algorithms that permit us to fully determine the influential coalitions. We distinguish three cases: a symmetric decomposable model, an anonymous model, and a general model.
Źródło:
Operations Research and Decisions; 2016, 26, 2; 69-85
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gold rush optimizer : a new population-based metaheuristic algorithm
Autorzy:
Zolf, Kamran
Powiązania:
https://bibliotekanauki.pl/articles/2204102.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold rush optimizer
metaheuristic
global optimization
population-based algorithm
Opis:
Today’s world is characterised by competitive environments, optimal resource utilization, and cost reduction, which has resulted in an increasing role for metaheuristic algorithms in solving complex modern problems. As a result, this paper introduces the gold rush optimizer (GRO), a population-based metaheuristic algorithm that simulates how gold-seekers prospected for gold during the Gold Rush Era using three key concepts of gold prospecting: migration, collaboration, and panning. The GRO algorithm is compared to twelve well-known metaheuristic algorithms on 29 benchmark test cases to assess the proposed approach’s performance. For scientific evaluation, the Friedman and Wilcoxon signed-rank tests are used. In addition to these test cases, the GRO algorithm is evaluated using three real-world engineering problems. The results indicated that the proposed algorithm was more capable than other algorithms in proposing qualitative and competitive solutions.
Źródło:
Operations Research and Decisions; 2023, 33, 1; 113--150
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An approximation algorithm for multi-unit auctions: numerical and subject experiments
Autorzy:
Takahashi, S.
Izunaga, Y.
Watanabe, N.
Powiązania:
https://bibliotekanauki.pl/articles/406625.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
multi-unit auctions
approximation algorithm
experiment
algorytm aproksymacyjny
eksperyment
Opis:
In multi-unit auctions for a single item, the Vickrey–Clarke–Groves mechanism (VCG) attains allocative efficiency but suffers from its computational complexity. Takahashi and Shigeno thus proposed a greedy based approximation algorithm (GBA). In a subject experiment there was truly a difference in efficiency rate but no significant difference in seller’s revenue between GBA and VCG. It is not clear in theory whether each bidder will submit his or her true unit valuations in GBA. We show, however, that in a subject experiment there was no significant difference in the number of bids that obey “almost” truth-telling between GBA and VCG. As for individual bidding behavior, GBA and VCG show a sharp contrast when a human bidder competes against machine bidders; underbidding was observed in GBA, while overbidding was observed in VCG. Some results in a numerical experiment are also provided prior to reporting those observations.
Źródło:
Operations Research and Decisions; 2018, 28, 1; 95-115
2081-8858
2391-6060
Pojawia się w:
Operations Research and Decisions
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precise sub-pixel size measurement with linear interpolation
Autorzy:
Yin, A
Yang, Z
Long, G
Powiązania:
https://bibliotekanauki.pl/articles/174568.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
geometry size measurement
linear image sensor
linear interpolation algorithm
Opis:
High precision automated size measurements are required during industrial and scientific applications. The principle of sub-pixel measuring is based on an intensity interpolation algorithm. Combined with the characteristics of light, a system with high precision, short measuring time and low cost was developed. The proposed system is then applied to the measurement of 5 cm objects and compared with traditional measuring techniques. The experiment demonstrates that the measuring accuracy can reach up to 0.012 μm, and that the measurement size of the system is practical and prompt. In addition, it is able to meet the requirement for industrial applications in a variety of settings with stable performance and high precision.
Źródło:
Optica Applicata; 2015, 45, 1; 113-123
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Control Strategy of Parallel Systems with Efficiency Optimisation in Switched Reluctance Generators
Autorzy:
Zan, Xiaoshu
Lin, Hang
Xu, Guanqun
Zhao, Tiejun
Gong, Yi
Powiązania:
https://bibliotekanauki.pl/articles/1956008.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
switched reluctance generator
parallel system
efficiency optimization
differential evolution algorithm
Opis:
To solve motor heating and life shortening of parallel switched reluctance generator (SRG) induced by uneven output currents due to different external characteristics, we generally adopt current sharing control (CSC) to make each parallel generator undertake large load currents on average to improve the reliability of parallel power generation system. However, the method usually causes additional loss of power because it does not consider the efficiency characteristics of each parallel generator. Therefore, with the efficiency expression for the parallel system of SRG established and analysed, the control strategy based on differential evolution (DE) algorithm is proposed as a mechanism by which to enhance generating capacity and reliability of multi-machine power generation from the perspective of efficiency optimisation. We re-adjust the reference current of each parallel generator to transform the working point of each generator and implement the efficiency optimisation of parallel system. The performance of the proposed control method is evaluated in detail by the simulation and experiment, and comparison with traditional CSC is carried out as well.
Źródło:
Power Electronics and Drives; 2021, 6, 41; 61-74
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Construction of Variable Strength Covering Array for Combinatorial Testing Using a Greedy Approach to Genetic Algorithm
Autorzy:
Bansal, P
Sabharwal, S
Mittal, N
Arora, S
Powiązania:
https://bibliotekanauki.pl/articles/384137.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
combinatorial testing
variable strength covering array
genetic algorithm
greedy approach
Opis:
The limitation of time and budget usually prohibits exhaustive testing of interactions between components in a component based software system. Combinatorial testing is a software testing technique that can be used to detect faults in a component based software system caused by the interactions of components in an effective and efficient way. Most of the research in the field of combinatorial testing till now has focused on the construction of optimal covering array (CA) of fixed strength t which covers all t-way interactions among components. The size of CA increases with the increase in strength of testing t, which further increases the cost of testing. However, not all components require higher strength interaction testing. Hence, in a system with k components a technique is required to construct CA of fixed strength t which covers all t-way interactions among k components and all ti-way (where ti > t) interactions between a subset of k components. This is achieved using the variable strength covering array (VSCA). In this paper we propose a greedy based genetic algorithm (GA) to generate optimal VSCA. Experiments are conducted on several benchmark configurations to evaluate the effectiveness of the proposed approach.
Źródło:
e-Informatica Software Engineering Journal; 2015, 9, 1; 87-105
1897-7979
Pojawia się w:
e-Informatica Software Engineering Journal
Dostawca treści:
Biblioteka Nauki
Artykuł

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