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Wyszukujesz frazę "algorithms" wg kryterium: Temat


Tytuł:
Biologically inspired methods for control of evolutionary algorithms
Autorzy:
Stańczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/206262.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
algorytm genetyczny
adaptacja
adaptacyjny algorytm ewolucyjny
genetic algorithms
adaptation
adaptive ewolutionary algorithms
Opis:
In this paper two methods for evolutionary algorithm control are proposed. The first one is a new method of tuning tlie probabilities of genetic operators. It is assumed in the presented approach that every member of the optimized population conducts his own ranking of genetic operators' qualities. This ranking enables computing the probabilities of execution of genetic operators. This set of probabilities is a basis of experience of every individual and according to this basis the individual chooses the operator in every iteration of the algorithm. Due to this experience one can maximize the chances of his offspring to survive. The second part of the paper deals with a self-adapting method of selection of individuals to a subsequent generation. Methods of selection applied in the evolutionary algorithms are usually inspired by nature and prefer solutions where the main role is played by randomness, competition and struggle among individuals. In the case of evolutionary algorithms, where populations of individuals are usually small, this causes a premature convergence to local minima. In order to avoid this drawback I propose to apply an approach based rather on an agricultural technique. Two new methods of object selection are proposed: a histogram selection and a mixed selection. The methods described were tested using examples based on scheduling and TSP.
Źródło:
Control and Cybernetics; 2003, 32, 2; 411-433
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolutionary approach to obtain graph covering by densely connected subgraphs
Autorzy:
Stańczak, J.
Potrzebowski, H.
Sęp, K.
Powiązania:
https://bibliotekanauki.pl/articles/206170.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
graph
clique
graph clustering
evolutionary algorithms
Opis:
This article describes two evolutionary methods for dividing a graph into densely connected structures. The first method deals with the clustering problem, where the element order plays an important role. This formulation is very useful for a wide range of Decision Support System (DSS) applications. The proposed clustering method consists of two stages. The first is the stage of data matrix reorganization, using a specialized evolutionary algorithm. The second stage is the final clustering step and is performed using a simple clustering method (SCM). The second described method deals with a completely new partitioning algorithm, based on the subgraph structure we call α-clique. The α-clique is a generalization of the clique concept with the introduction of parameter α, which imposes for all vertices of the subgraph the minimal percentage (α*100%) of vertices of this subgraph that must be connected with vertices of this α-clique. Traditional clique is an instance of α-clique with α = 1. Application of this parameter makes it possible to control the degree (or strength) of connections among vertices (nodes) of this subgraph structure. The evolutionary approach is proposed as a method that enables finding separate α-cliques that cover the set of graph vertices.
Źródło:
Control and Cybernetics; 2011, 40, 3; 849-875
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bin packing with restricted item fragmentation
Autorzy:
Pieńkosz, K.
Powiązania:
https://bibliotekanauki.pl/articles/205659.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
bin packing
fragmentable items
approximation algorithms
Opis:
In this paper we consider a generalization of the bin packing problem, in which it is permitted to fragment the items while packing them into bins. There is, however, a restriction that the size of each piece of the fragmented item cannot be smaller than a given parameter β An interesting aspect of such a model is that if β= 0, then the problem can be easily solved optimally. If β is large enough, meaning, in fact, that the fragmentation is not allowed, we get the classical bin packing problem, which is NP-hard in the strong sense. We present approximation algorithms for solving the problem and analyse their properties. The results of computational experiments and conclusions relating to the effectiveness of the algorithms are also presented.
Źródło:
Control and Cybernetics; 2014, 43, 4; 547-556
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new optimal algorithm for a time-dependent scheduling problem
Autorzy:
Kubale, M.
Ocetkiewicz, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/969669.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
scheduling
single machine
deteriorating jobs
total completion time
algorithms
Opis:
In this article a single machine time-dependent scheduling problem with total completion time criterion is considered. There are n given jobs, j1,...,jn, and the processing time pi of the i-th job is given by pi = 1 + biSi, where si is the starting time of the i-th job, i = 1,...n. If all jobs have different and non-zero deterioration rates and bi [wzór], where bmin = min{bi}, then an optimal schedule can be found in O(n log n) time. The conducted computational experiments show that the presented algorithm performs very well even on data not satisfying the assumed constraints.
Źródło:
Control and Cybernetics; 2009, 38, 3; 713-721
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An efficient genetic algorithm for the uncapacitated multiple allocation p-hub median problem
Autorzy:
Stanimirovic, Z.
Powiązania:
https://bibliotekanauki.pl/articles/970612.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
p-hub problem
genetic algorithms
discrete location and assignment
Opis:
In this paper the Uncapacitated Multiple Allocation p-hub Median Problem (the UMApHMP) is considered. A new heuristic method based on a genetic algorithm approach (GA) for solving UMApHMP is proposed. The described GA uses binary representation of the solutions. Genetic operators which keep the feasibility of individuals in the population are designed and implemented. The mutation operator with frozen bits is used to increase the diversibility of the genetic material. The running time of the GA is improved by caching technique. Proposed GA approach is bench-marked on the well known CAB and AP data sets and compared with the existing methods for solving the UMApHMP. Computational results show that the GA quickly reaches all previously known optimal solutions, and also gives results on large scale AP instances (up to n=200, p=20) that were not considered in the literature so far.
Źródło:
Control and Cybernetics; 2008, 37, 3; 669-692
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grammars in genetic programming
Autorzy:
Wieczorek, W.
Czech, Z.
Powiązania:
https://bibliotekanauki.pl/articles/205856.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
algorytm genetyczny
gramatyka
genetic algorithms
grammars
strongly typed genetic programming
Opis:
The work consists of two parts. In the first part the idea of genetic programming is presented and the basic elements of a genetic programming system are described. In the second part, considering a selected example, we describe the results of investigations of the influence of program grammars on the efficiency of genetic programming.
Źródło:
Control and Cybernetics; 2000, 29, 4; 1019-1030
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic flows with supply and demand
Autorzy:
Ciurea, E.
Powiązania:
https://bibliotekanauki.pl/articles/205598.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
algorytm grafowy
przepływ dynamiczny
sieć
dynamic flows
graph algorithms
networks
Opis:
We are given a network G = (N, A, h, c) with node set N, arc set A, time function h, capacity function c, and P the set of periods, s the source and s' the sink of the network G. Associated with s, there is a non-negative real number q(t) called the supply of source s at time t, and with s' - a nonnegative real number q'(t) called the demand of sink s' at time t, t [belongs to] P. The objective is to determine the existence of a dynamic flow in G for p periods, so that the demands at sink s' can be fulfilled from the supplies at the source s. A numerical example is presented.
Źródło:
Control and Cybernetics; 2000, 29, 4; 895-903
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New evaluations of ant colony optimization start nodes
Autorzy:
Fidanova, S.
Marinov, P.
Atanassov, K.
Powiązania:
https://bibliotekanauki.pl/articles/206546.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
combinatorial optimization
ant algorithms
start nodes evaluation
semi random start
Opis:
Ant Colony Optimization (ACO) is a stochastic search method that mimics the social behavior of real ant colonies, managing to establish the shortest route to the feeding sources and back. Such algorithms have been developed to arrive at near-optimal solutions to large-scale optimization problems, for which traditional mathematical techniques may fail. In this paper, the semi-random start procedure is applied. A new kind of evaluation of start nodes of the ants is developed and several starting strategies are prepared and combined. The idea of semi-random start is related to a better management of the ants. This new technique is tested on the Multiple Knapsack Problem (MKP). A Comparison among the strategies applied is presented in terms of quality of the results. A comparison is also carried out between the new evaluation and the existing one. Based on this comparative analysis, the performance of the algorithm is discussed. The study presents the idea that should be beneficial to both practitioners and researchers involved in solving optimization problems.
Źródło:
Control and Cybernetics; 2014, 43, 3; 471-485
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solving Markov decision processes by d-graph algorithms
Autorzy:
Kátai, Z.
Powiązania:
https://bibliotekanauki.pl/articles/205688.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
Markov decision processes
dynamic programming
graph representation
graph algorithms
optimization problems
Opis:
Markov decision processes (MDPs) provide a mathematical model for sequential decisionmaking (sMDP/dMDP: stochastic/ deterministic MDP). We introduce the concept of generalized dMDP (g-dMDP) where each action may result in more than one next (parallel or clone) state. The common tools to represent dMDPs are digraphs, but these are inadequate for sMDPs and g-dMDPs. We introduce d-graphs as general tools to represent all the above mentioned processes (stationary versions). We also present a combined d-graph algorithm that implements dynamic programming strategies to find optimal policies for the finite/infinite horizon versions of these Markov processes. (The preliminary version of this paper was presented at the Conference MACRo 2011.)
Źródło:
Control and Cybernetics; 2012, 41, 3; 577-593
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Learning board evaluation function for Othello by hybridizing coevolution with temporal difference learning
Autorzy:
Szubert, M.
Jaśkowski, W.
Krawiec, K.
Powiązania:
https://bibliotekanauki.pl/articles/206175.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
evolutionary computation
coevolutionary algorithms
reinforcement learning
memetic computing
game strategy learning
Opis:
Hybridization of global and local search techniques has already produced promising results in the fields of optimization and machine learning. It is commonly presumed that approaches employing this idea, like memetic algorithms combining evolutionary algorithms and local search, benefit from complementarity of constituent methods and maintain the right balance between exploration and exploitation of the search space. While such extensions of evolutionary algorithms have been intensively studied, hybrids of local search with coevolutionary algorithms have not received much attention. In this paper we attempt to fill this gap by presenting Coevolutionary Temporal Difference Learning (CTDL) that works by interlacing global search provided by competitive coevolution and local search by means of temporal difference learning. We verify CTDL by applying it to the board game of Othello, where it learns board evaluation functions represented by a linear architecture of weighted piece counter. The results of a computational experiment show CTDL superiority compared to coevolutionary algorithm and temporal difference learning alone, both in terms of performance of elaborated strategies and computational cost. To further exploit CTDL potential, we extend it by an archive that keeps track of selected well-performing solutions found so far and uses them to improve search convergence. The overall conclusion is that the fusion of various forms of coevolution with a gradient-based local search can be highly beneficial and deserves further study.
Źródło:
Control and Cybernetics; 2011, 40, 3; 805-831
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An optimized soft computing-based passage retrieval system
Autorzy:
Ortiz-Arroyo, D.
Christensen, H. U.
Powiązania:
https://bibliotekanauki.pl/articles/970939.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
information retrieval
question answering systems
passage retrieval
fuzzy logic
optimization
genetic algorithms
Opis:
In this paper we propose and evaluate a soft computing-based passage retrieval system for Question Answering Systems (QAS). Fuzzy PR, our base-line passage retrieval system, employs a similarity measure that attempts to model accurately the question reformulation intuition. The similarity measure includes fuzzy logic-based models that evaluate efficiently the proximity of question terms and detect term variations occurring within a passage. Our experimental results using FuzzyPR on the TREC and CLEF corpora show that our novel passage retrieval system achieves better performance compared to other similar systems. Finally, we describe the performance results of OptFuzzyPR, an optimized version of FuzzyPR, created by optimizing the values of FuzzyPR system parameters using genetic algorithms.
Źródło:
Control and Cybernetics; 2009, 38, 2; 457-479
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cost-efficient project management based on critical chain method with partial availability of resources
Autorzy:
Pawiński, G.
Sapiecha, K.
Powiązania:
https://bibliotekanauki.pl/articles/205579.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
project management and scheduling
resource allocation
resource constraints
metaheuristic algorithms
parallel processing
Opis:
Cost-efficient project management based on Critical Chain Method (CCPM) is investigated in this paper. This is a variant of the resource-constrained project scheduling problem (RCPSP) when resources are only partially available and a deadline is given, but the cost of the project should be minimized. RCPSP is a well- known NP hard problem but originally it does not take into consideration the initial resource workload. A metaheuristic algorithm driven by a metric of a gain was adapted to solve the problem when applied to CCPM. Refinement methods enhancing the quality of the results are developed. The improvement expands the search space by inserting the task in place of an already allocated task, if a better allocation can be found for it. The increase of computation time is reduced by distributed calculations. The computational experiments showed significant efficiency of the approach, in comparison with the greedy methods and with genetic algorithm, as well as high reduction of time needed to obtain the results.
Źródło:
Control and Cybernetics; 2014, 43, 1; 95-109
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimization of electric and magnetic losses in the speed control of induction motors
Autorzy:
Kawecki, L.
Powiązania:
https://bibliotekanauki.pl/articles/206296.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie optymalne
silnik indukcyjny
algorytmy genetyczne
optimal control
induction motors
genetic algorithms
Opis:
The article presents a minimization method of electric energy losses in rotor and stator windings and in the magnetic core of the motor during the frequency speed control of induction motors which limits the amplitude of the stator current. To solve this problem, the hybrid algorithm of parametric optimization, the mathematical model of the induction motor and the Pontryagin maximum principle are used. In the mathematical model of the motor both electromagnetic transients and the motor magnetic material saturation are taken into consideration. The electric energy losses in the magnetic core and in the windings of the motor are also calculated. An application example of the method developed for the idle starting of an induction motor is given.
Źródło:
Control and Cybernetics; 2003, 32, 2; 329-349
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heuristic algorithms for the optimization of total weighted completion time for asynchronous transmission in a packet data transmission system
Autorzy:
Piórkowski, A.
Werewka, J.
Bielecka, M.
Powiązania:
https://bibliotekanauki.pl/articles/206673.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
total weighted completion time
total cost factor
optimization
heuristic algorithms
packet transmission
Opis:
In this paper, the minimization of total weighted completion time (total cost) for asynchronous transmission in distributed systems is discussed. Special attention has been paid to the problem of message scheduling on the sender side. Messages to be sent form a queue, therefore the order in which they are to be sent has to be set. Scheduling algorithms can be chosen to optimize scheduling criteria such as total completion time or total weighted completion time. The message scheduling problem becomes complicated considerably when the transmitted data stream between the sender and the receiver is formed into packets. TheWSPT (Weighted Shortest Processing Time) scheduling rule, which orders messages according to non-decreasing length and weight ratios has been proven to be non-optimal. It has been demonstrated that the problem of minimizing the total weighted completion time is NP-hard. Here, we propose heuristic algorithms for scheduling messages and experimentally evaluate the performance of these scheduling algorithms.
Źródło:
Control and Cybernetics; 2014, 43, 4; 507-529
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability criteria for large-scale time-delay systems; the LMI approach and the Genetic Algorithms
Autorzy:
Chen, J.- D.
Powiązania:
https://bibliotekanauki.pl/articles/969948.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
algorytm genetyczny
delay-dependent criterion
large-scale systems
linear matrix inequality
genetic algorithms
Opis:
This paper addresses the asymptotic stability analysis problem for a class of linear large-scale systems with time delay in the state of each subsystem as well as in the interconnections. Based on the Lyapunov stability theory, a delay-dependent criterion for stability analysis of the systems is derived in terms of a linear matrix inequality (LMI). Finally, a numerical example is given to demonstrate the validity of the proposed result.
Źródło:
Control and Cybernetics; 2006, 35, 2; 291-301
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł

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