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Creative Mathematics
and Informatics



Print Edition: ISSN 1584 - 286X
Online Edition: ISSN 1843 - 441X


Creative Math. and Inf. is a category B+ journal in the CNCSIS classification

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Mathematical Reviews
Zentralblatt MATH

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Vol. 17 (2008), No. 3, 15 September 2009
Generating the basins of attraction for Newton's method
Author: Gheorghe Ardelean
Abstract: There are many ways to view the basins of attraction for Newton's method for complex polynomials. In the paper a program to perform this task is presented. It determines if the Newton's method is converging from any point in a rectangular domain in R  R, and computes the number of iterations necessary to attempt a root. The colors/number of iterations/roots and colors/roots diagrams are generated.
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No. of downloads: 176 Full access PDF |
Integral mean for fuzzy random variables
Author: Iuliana Carmen Bărbăcioru
Abstract: In this paper we give some convergence properties with respect to weakly convergence for integral mean of fuzzy random variables.
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No. of downloads: 130 Full access PDF |
Stabilizing discrete dynamical systems by monotone Krasnoselskij type iterative schemes
Author: Vasile Berinde / Gabriella Kovacs
Abstract: In this note monotone approximations of fixed points of real Lipschitz functions are produced by employing a variation controlling mechanism and a growth-rate controllingmechanism, both with generalized Krasnoselskij type iterations, and both inspired fromdiscrete dynamical systems.
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No. of downloads: 158 Full access PDF |
QSPR modelling of molar volume of alkanes using the ZEP topological index
Author: Zoița Mărioara Berinde
Abstract: In this paper it is presented a QSPR study between themolar volume (MV) andmolecular structure for a set of 70 alkanes using the ZEP topological index. The ZEP topological index is calculated by using the weighted electronic connectivity matrix, CEP, associated to the chemical graphs of alkanes introduced by the author in a previous paper.
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No. of downloads: 157 Full access PDF |
Some bivariate piecewise operators
Author: Marius M. Birou
Abstract: In this paper we construct some bivariate interpolation operators using chains of bivariate piecewise Hermite projectors which are parametrical extensions of corresponding univariate projectors. We study the convergence of these operators.
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No. of downloads: 130 Full access PDF |
On the stability of quartic type functional ecuation
Author: Florin Bojor
Abstract: In this article we investigate the generalized Hyers-Ulam-Rassias stability for the quartic type functional equationby using the fixed point alternative and we shall obtain a better estimate for the difference in norm of a solution of equation and a sub-solution of equation.
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No. of downloads: 139 Full access PDF |
Fixed point theory for multivalued contractions on a set with two b-metrics
Author: Monica Boriceanu
Abstract: The purpose of this paper is to present some fixed point results for multivalued contractions on a set with two b-metrics. The data dependence and the well-posedness of the fixed point problem are also discussed.
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No. of downloads: 167 Full access PDF |
A modified Seidel method for calculating the fixed points of contractive mappings
Author: Adrian Cărăbineanu
Abstract:
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No. of downloads: 135 Full access PDF |
Fixed point theory for nonself multivalued operators on a set with two metrics
Author: Cristian Chifu / Gabriela Petrusel
Abstract: The purpose of this work is to present some fixed point results for multivalued operators on a set with two metrics. The data dependence and the well-posedness of the fixed point problem are also discussed.
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No. of downloads: 133 Full access PDF |
Complex dynamics in a collaborative evolutionary search model
Author: Camelia Chira / Anca Gog / Daniela Zaharia / Dan Dumitrescu
Abstract: The distributed collaborative evolutionary model analyzed in this paper is characterized by structuring the population using a fitness guided topology and by assigning the individuals to three societies characterized by differentmating strategies. Themembership of offsprings to societies is decided in a probabilistic manner using a dominance probability. The influence of this dominance probability on the dynamics of societies sizes is analyzed both empirically and theoretically. Consequently, values of the dominance probability leading to particular distributions of the population elements in societies are identified. Numerical experiments indicate a good performance of the proposed model.
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No. of downloads: 134 Full access PDF |
A problem of entropy generation in a channel filled with a porous medium
Author: Dalia Cîmpean / Nicolaie Lungu / Ioan Pop
Abstract: The problem studied is that of entropy generation for mixed convection in an inclined channel. The channel is filled with a porous medium and has an uniformwall heat flux. The flow is upward and the heat flux is into the channel. The solutions of the governing Darcy and energy equations are used for analyzing the entropy generation and the Bejan number into the channel. The results are plotted and studied for different important parameters involved and for different inclinations angle of the channel.
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No. of downloads: 155 Full access PDF |
BBUFs: Synchronization mechanism
Author: Dan Cojocar
Abstract: Peer-to-peer systems are distributed systems without any centralized control or hierarchical organization. All nodes from a system have identical capabilities and responsibilities, and all communications are symmetric. BBUFs (Babes-Bolyai University File System) is a peer-to-peer file system. The ?le systemis designed for ordinary Unixmachines that are IPV6 capable. In this paperwe present our approach regarding the synchronization mechanism.
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No. of downloads: 133 Full access PDF |
A multiagent based approach for national cancer registry management
Author: Grigoreta Sofia Cojocar / Adriana-Mihaela Guran / Teodora Sanislav / Gabriela Czibula
Abstract: Cancer registry is an informational system for acquiring, managing and analyzing information about neoplazic disease persons. Its purpose is to provide accurate information about cancer occurrence in a particular geographical region. In this paper we present a proposal for the architecture of a multiagent system for national cancer registry.
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No. of downloads: 127 Full access PDF |
A method for improving the error diffusion algorithms
Author: Ovidiu Cosma
Abstract: In this paper, a method for compensating the softening effect of the error diffusion algorithms, and a new dithering technique that emphasizes the details of images and is based entirely on the wavelet transform, are presented
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No. of downloads: 124 Full access PDF |
Assessing the ecologic-economic efficiency of an investment policy
Author: Gabriela Cristescu / Liviu Sevastian Bocii / Laurențiu Jitaru
Abstract: We present a manner of assessing the ecologic-economic efficiency of an investment project, which provides the decision maker with an inner characterization of the project, depending only on the results of the project itself. The mathematical model is based on multiple criteria binary programming. The solution of this model leads the decision maker to using an ecologic-economic efficiency index, which arises from finding a Pareto point of the multiple criteria programming problem. The possibility of gambling with the relative importance of criteria provides the decision maker with extended information on the consequences of the investment project on the environment. The stability properties of the multiple criteria decision making technique based on the ecologic-economic ef?ciency index is studied, determining the intervals of stability. Our method is tested on the problem of modernizing the Romanian rail from ecologic point of view.
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No. of downloads: 114 Full access PDF |
Some applications of the fixed-point theory in economics
Author: Rodica-Mihaela Danet / Marian-Valentin Popescu
Abstract: In this paper, firstly we prove some fixed-point results and then we apply these results in economics, giving two general equilibrium theorems. These theorems give sufficient conditions for the existence of an equilibrium point (and a maximal element) for a generalized abstract economy (respectively for a qualitative game).
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No. of downloads: 148 Full access PDF |
Numerical investigations of the dynamic problem in thin thermoelastic plates
Author: Remus Ene / Ioana Dragomirescu
Abstract: An operatorial approach for the equations obtained by the homogenization method in the case of thin thermoelastic porous plates is introduced. Based on this formulation an uniqueness theorem concerning the solution is deduced. The dynamical equations obtained by the homogenization method for thin thermoelastic porous plates are numerically investigated showing a stabilization of the solution.
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No. of downloads: 129 Full access PDF |
The influences of distances measures for speaker identification
Author: Marieta Gâta / Gavril Toderean
Abstract: This paper is a study which compare statistical features of long term text-independent speaker identification .We compare by statistical methods four distances: the City block, Euclidean, Weighted Euclidean and Mahalanobis distance measures. Experiments confirm our assumption that Weighted Euclidean distance performs better then the other three distances.
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No. of downloads: 141 Full access PDF |
A multivalued Perov-type theorem in generalized metric spaces
Author: Liliana Guran
Abstract: In this paper we recall the concept of multivalued weakly Picard operator. Then we present a fixed points result for multivalued contractive type operators with respect to a w-distance.
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No. of downloads: 117 Full access PDF |
Quality evaluation of the software product approach
Author: Mara Hajdu-Macelaru
Abstract: We will provide in this paper an approach of evaluating the quality of the software product, using in the planning and developing phase of the product the two approaches that exists in the literature: Quality Function Deployment approach (QFD) and Goal Question Metric approach (GQM).
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No. of downloads: 134 Full access PDF |
A Perov-type fixed point theorem in generalized ordered metric spaces
Author: Natalia Jurja
Abstract: In this paper we prove a Perov-type fixed point theorem in generalized ordered metric spaces.
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No. of downloads: 136 Full access PDF |
The crossing number of P2 5
Author: Marian Klesc / Daniela Kravecova
Abstract: Patil and Krishnnamurthy established family of graphs for which power graphs have crossing number one. This is the only result concerning crossing numbers of power of some graphs. Let P 2 m denote the power of the path Pm. We start to determine crossing numbers of a new in?nite family of graphs, concretely for the Cartesian products P 2 mCn wherem  2 and n  3. The main result of the paper is that the crossing number of the graph P2 5  Cn is 4n for all n  3.
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No. of downloads: 139 Full access PDF |
On some existence and uniqueness theorems for Fredholm and Volterra equations with modified argument
Author: Monica Lauran
Abstract: In this paper some existence and uniqueness theorems for a Fredholm, respectively, a Volterra integral equation, are given by using the contraction mapping principle and the generalized contraction principle, respectively. These integral equations arise in several concrete applications such as theory of optimal control, economics and etc.
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No. of downloads: 141 Full access PDF |
Fixed points for non-self nonlinear contractions and non-self Caristi type operators
Author: Tania A. Lazar
Abstract: The purpose of this paper is to discuss some basic problems of the fixed point theory for non-self singlevalued operators on a set with two metrics. The results complement and extend some known results in the literature.
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No. of downloads: 143 Full access PDF |
Dynamic transport problems of cost type and time type
Author: Liana Lupsa / Dorel I. Duca / Ioana Chiorean / Luciana Neamtiu
Abstract: Real problems which arise in Health Economy are mathematically modeled by means of dynamic optimization problems of transport type. The aim of this paper is to study them and to give some methods to solve them.
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No. of downloads: 130 Full access PDF |
A finite element approximation for the complex geometry of the carotid artery
Author: Ana Marina Ioana Maierean
Abstract: Given a parametric model of a tubular object-a generalized cylinder with elliptical or cylindrical cross-section combined with a deformable model, an alternative finite element method is used-the so called web-method in order to provide an approximate solution over all elements. This is obtained by assuming a weighted function to relate internal values on the constructed grid.
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No. of downloads: 135 Full access PDF |
Gamma approximating operators
Author: Vasile Miheșan
Abstract: By using the gamma distribution we shall define a general linear transform from, which we obtain as special cases the gamma first kind transform. For different value of , and a we obtain several gamma type operators studied in literature. We apply the gamma first kind transform to Szasz-Mirakjan's operator and we obtain the Jain-Pethe operator
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No. of downloads: 123 Full access PDF |
The stability conditions associated to the jump processes
Author: Radu Moleriu
Abstract: In this paper we study the evolution solutions of the stochastic differential equation associated to a Poisson process. As well, we present the conditions for the exponentially stability making connections between the norm of the operators which appears in the stochastic differential equation and the increase index associated to the semigroup operators.
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No. of downloads: 132 Full access PDF |
Component classification criteria for a platform - independent component repository
Author: Simona Motogna / Ioan Lazar / Bazil Parv / Istvan Czibula / L. Lazar
Abstract: Component repository is an essential part of a framework for software component definition, validation, and composition that we have developed so far. The components are stored into the repository such that search and retrieve operations will be as efficient as possible. We propose some classification criteria for components based on their signatures and functionalities. These criteria also take into consideration the specifications of the platform-independent component model for dynamic execution environment.
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No. of downloads: 144 Full access PDF |
Existence and behavior of solutions of a system of quasilinear differential equations
Author: Alma Omerspahic
Abstract: This paper deals with behavior, approximation and stability of some solutions of the system of quasilinear differential equations. The behavior of solutions in the neighborhood of an arbitrary curve is considered, with extraordinary attention on some spacial cases. The obtained results contain an answer to the question on approximation as well as stability of solution whose existence is established. The errors of the approximation are defined by the function that can be sufficiently small. The theory of qualitative analysis of differential equations and topological retraction method are used.
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No. of downloads: 138 Full access PDF |
Noncommutative differential direct Lie derivative and the algebra of special Euclidean group SE(2)
Author: Laurian Ioan Pișcoran
Abstract: A Lie algebra is an algebraic structure whose main use is in studying geometric objects such as Lie groups and differentiable manifolds. The term Lie algebra(after Sophus Lie) was introduced by Hermann Weyl in the 1930s. Using the Lie algebra of the special euclidean group SE(2) and using notions of noncommutative geometry, we can construct a new derivative which I call it direct Lie derivative. Also in this paper we de?ne an real inner product for A,B? se(2) two elements of the Lie algebra se(2). The main result of this paper consist in the proof that we can generate other Lie algebras using the direct Lie derivative elements.
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No. of downloads: 132 Full access PDF |
n-Groups derivable from groups
Author: Vasile Pop
Abstract:
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No. of downloads: 142 Full access PDF |
Component selection based on fuzzy clustering analysis
Author: Camelia Serban / Andrea Vescan / Horia F. Pop
Abstract: Component Based Software Engineering (CBSE) is concerned with the assembly of pre-existing software components. Component selection is a crucial problem in CBSE. The problem of selecting the best candidate from a set of available components is discussed in this paper. Fuzzy clustering analysis is used to classify the components into different groups based on the values of metrics that measure different attributes of the components. The choice of the best component is based on the obtained classifications.
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No. of downloads: 160 Full access PDF |
Computation of bounds for polynomial roots
Author: Doru Stefănescu
Abstract: We discuss some old and new results on bounds for roots of univariate polynomials, emphasizing on new methods concerning real roots of univariate polynomials with real coefficients. There are presented new methods for computing bounds for positive roots of univariate polynomials. We compare our results with known upper bounds for positive roots.
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No. of downloads: 139 Full access PDF |
Semifixed sets for multivalued '-contractions
Author: Ioana Camelia Tise
Abstract: The purpose of this paper is to present some semifixed set theorems for multivalued '-contractions. Our results generalize some recent theorems by F. S. De Blasi. As an application, existence and uniqueness for the solution of a set integral equation is obtained.
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No. of downloads: 140 Full access PDF |
Empirical study of the rate of convergence of some Newton type methods
Author: Cristina Țicală / Laszlo Balog
Abstract: In this paper an empirical study of the rate of convergence of some Newton type methods is made. It is originating in the formula... Some numerical examples to illustrate the study are also given.
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No. of downloads: 138 Full access PDF |
Influence of deterministic trend on the estimated parameters of GARCH(1,1) model
Author: Calin Vamos / Maria Craciun
Abstract: The log returns of financial time series are usually modeled by means of the stationary GARCH(1,1) stochastic process or its generalizations which can not properly describe the nonstationary deterministic components of the original series. We analyze the influence of deterministic trends on the GARCH(1,1) parameters using Monte Carlo simulations. The statistical ensembles contain numerically generated time series composed by GARCH(1,1) noise superposed on deterministic trends. The GARCH(1,1) parameters characteristic for financial time series longer than one year are not affected by the detrending errors. We also show that if the ARCH coefficient is greater than the GARCH coef?cient, then the estimated GARCH(1,1) parameters depend on the number of monotonic parts of the trend and on the ratio between the trend and the noise amplitudes.
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No. of downloads: 135 Full access PDF |
Dependencies in the component selection problem
Author: Andreea Vescan
Abstract: Component Selection is a crucial problem in Component-Based Software Engineering. We adapt a Greedy approach to construct a component-based system by introducing a new selection function. The new selection decision takes into account not only the cost of the components but also their interplay. The case study shows that considering the dependencies between the components the cost of the obtained solution may be higher due to the new selection improvement condition, but no dependencies between the selected components exist.
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No. of downloads: 161 Full access PDF |
On the finiteness of the reachability set for jumping Petri nets
Author: Cristian Vidrascu
Abstract: In this paper we extend the decidability result concerning the finiteness of the reachability set of a net from classical Petri nets to jumping Petri nets.
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No. of downloads: 135 Full access PDF |
Behavior of symmetric reaction-diffusion problems near their critical values
Author: Panayiotis M. Vlamos
Abstract: We study the behavior of the Gelfand problem in its symmetric form and in the case where the critical value of the positive parameter delta does not belong in the spectrum of solutions of the corresponding steady-state problem. Using comparison techniques we obtain suitable upper and lower time-dependent solutions, which lead us to estimations of the time-dependent solution and of the blow-up time.
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No. of downloads: 123 Full access PDF |
A survey on cycles embeddings in Fibonacci and extended Fibonacci cubes
Author: Ioana Zelina
Abstract: The Fibonacci and extended Fibonacci cubes are two topologies used for interconnection networks in distributed systems, inspired by the Fibonacci numbers. The possibility of embedding basic interconnection topologies in Fibonacci and extended Fibonacci cubes is an important issue that defines the properties of these topologies. In this paper we give a survey on the property of the existence of a Hamiltonian cycle in Fibonacci and extended Fibonacci cubes, property which is very important, especially in the presence of faulty links when a reconfiguration of the network can be necessary.
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No. of downloads: 135 Full access PDF |


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