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 20.07.2017
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 Indexed by: Mathematical Reviews Zentralblatt MATH Current rejection rate: 37.5 % RSS

Vol. 12 (2003),
 Some applications of integral sums Author: P. Kortesi Abstract: The correct introduction of definite integrals plays an important role in teaching analysis. This paper is aimed to present one of the possible applications of definite integrals, which could serve the deeper understanding of the basic notion, to show how the basic definition ''is working''. The paper is partially supported by the didactical research cooperation due to the CEEPUS network H127. PDF | DVI | PS | No. of downloads: 849 Full access PDF | DVI | PS | Improper integrals and Riemann sums Author: Gabriella Kovacs Abstract: The aim of this note is to give simple examples of absolutely convergent improper integrals having integral sums whose limit does not equal the value of the integral. PDF | DVI | PS | No. of downloads: 492 Full access PDF | DVI | PS | Some geometric transformations and their connections to complex numbers Author: Gh. Miclauș Abstract: In the twelve form textbooks ([2], [3]) are presented some groups of geometric transformations: homotheties, translations, rotations etc. In this paper we will present two geometric transformations and we will show their relationship to groups of complex functions of the same type, namely isomorphic structures: the group of the rotations of a polygon with n vertices and Klein's group. At the end, we will show that the type of the group of the rotations of a regular polygon with four vertices (the square) and Klein's group of geometric transformations exhaust all types of groups of order 4. PDF | DVI | PS | No. of downloads: 426 Full access PDF | DVI | PS | On approximating the inverse of matrix Author: Ion Păvăloiu Abstract: In this note we deal with two problems: the first regards the efficiency in approximating the inverse of a matrix by the Shulz-type methods, and the second is the problem of evaluating the errors in the approximation of the inverses of the perturbed matrices. PDF | DVI | PS | No. of downloads: 457 Full access PDF | DVI | PS | Quadrilaterals in which an angle is the mean of the other angles Author: Maria Sânziana Pop / Ileana Balazs / Gh. Miclauș Abstract: PDF | DVI | PS | No. of downloads: 443 Full access PDF | DVI | PS | Some remarks on orthogonal polynomials Author: Ovidiu T. Pop Abstract: In this article we demonstrate some general results, from which, through particularities, we obtain identities satisfied by Legendre's, Laguerre's and Hemite's polynomials. PDF | DVI | PS | No. of downloads: 477 Full access PDF | DVI | PS | On some inequalities for right triangles Author: Ovidiu T. Pop / Constantin Voicu Abstract: We will prove some inequalities between the elements of a right triangle. PDF | DVI | PS | No. of downloads: 572 Full access PDF | DVI | PS | Using Prolog for the study of algebraic structures and complex operations Author: D. Popa Abstract: Should mathematicians learn the Prolog language? Due to its ability of modeling algebraic structures having complex operations and its backtracking algorithm able to scan a search space looking for solutions, Prolog becomes a great tool to study complex algebraic structures. The model of interactions between compilers when computer scientists are attempting to bootstrap a system or to create a new language or a new compiler is such an algebraic structure. This paper tries to answer yes'' our previous question. PDF | DVI | PS | No. of downloads: 427 Full access PDF | DVI | PS | Danilovskaia's problem, revisited Author: R. Răducanu Abstract: The present paper describes a thermal shock problem on a semi-space within the frame of linear thermoelasticity. The analytical solution is obtained and two types of a finite difference numerical algorithm to solve the problem are also described. The solutions are discussed. PDF | DVI | PS | No. of downloads: 407 Full access PDF | DVI | PS | A matrix method for obtaining the spline collocation function Author: Magnolia Rebeles Abstract: In this paper it is presented a procedure for obtaining a spline collocation function which approximate the solution of the initial value problem in linear differential equation, using a matrix method. There are also presented some results of implementing a Borland C program for a linear differential equation with initial values. PDF | DVI | PS | No. of downloads: 408 Full access PDF | DVI | PS | The limitations of JPEG compression Author: Ovidiu Cosma Abstract: The JPEG (Joint Photographic Experts Group) compression standard is based on the Discrete Cosine Transform. This transform was chosen for efficiency, but has the major disadvantage that it does not localize the frequency components in space. Because of that, the image has to be partitioned prior transform, and the margins of the blocks become visible at high compression ratios. This problem is solved in the JPEG 2000 standard, which uses the Discrete Wavelet Transform. PDF | DVI | PS | No. of downloads: 428 Full access PDF | The Window Fourier Transform -- a suitable alternative for image compression? Author: Ovidiu Cosma Abstract: The Discrete Cosine Transform [6], [8] on which the best-known image compression schemes are based [7], [1], has the major disadvantage that it does not localize the frequency components in time. The Window Fourier Transform (WFT) [3], [4], [5] solves this problem, but has limitations related to the resolutions in time and frequency. This article contains a visual evaluation of the WFT characteristics. PDF | DVI | PS | No. of downloads: 440 Full access PDF | Some aspects regarding the Internet protocol next generation Author: Adriana Diaconescu Abstract: This paper presents some different ideas and opinions about the new version of Internet Protocol (IP) -- IPng, also known as IPv6. IPng is designed as an evolutionary upgrade to the Internet Protocol and will, in fact, coexist with the older IPv4 for some time. This paper also reviews the features of the IPv6 protocol, the transition between today's IPv4 Internet and a future IPv6-based one, the structure of an IPv6 packet, the IPv6 header. PDF | DVI | PS | No. of downloads: 404 Full access PDF | DVI | PS | A combined turbo code with adaptive predistortion scheme for a non-linear channel Author: N. Rodriguez / R. Soto / W. Palma Abstract: PDF | DVI | PS | No. of downloads: 444 Full access PDF | DVI | PS | A simulation of the action of terrestrial gravitation Author: Cristian Eduard Rusu Abstract: This paper is a simple illustration of how a low-degree-difficulty abstract formula, concerning a physical phenomenon, can be implemented in an interactive and graphically suggestive way, with the use of a computer. A short historical view on the subject is included. Input data sets and graphic results are presented. PDF | DVI | PS | No. of downloads: 402 Full access PDF | DVI | PS | Forecasting methods and stock market analysis Author: Virginica Rusu / Cristian Rusu Abstract: The paper briefly analysis the methods used in forecasting of the stock market quotations, from the classic methods, used by the fundamentalists and chartist annalists, to the newest methods. The practical situations, where the analyzed methods are suitable, are also indicated. PDF | DVI | PS | No. of downloads: 481 Full access PDF | DVI | PS | Theon of Alexandria and Hypatia Author: M. Lambrou Abstract: In this paper we present the story of the most famous ancient female mathematician, Hypatia, and her father Theon of Alexandria. PDF | DVI | PS | No. of downloads: 434 Full access PDF | DVI | PS | Computer science higher education in Chile Author: Cristian Rusu Abstract: This paper is analyzing the Computer Science higher education system in Chile. A case study was chosen: Pontificia Universidad Catolica de Valparaiso. The problems regarding higher education in Computer Science are, generally speaking, similar in all countries. The system has to develop in harmony with the systems used abroad, taking advantage of the experience of others. PDF | DVI | PS | No. of downloads: 425 Full access PDF | DVI | PS | Preliminaries for the teaching of non-Euclidean geometries Author: Katalin Munkacsy Abstract: According to contemporary principles of methodology, there are good reasons for teaching the three geometries - namely Euclidean, spherical and hyperbolic - in parallel, despite the belief of some teachers that it makes little sense in contemporary conditions. I have been looking for historical data that prove that this parallelism is natural, and precedents can be found not only in ancient Greek history, but also in the Hungarian history of science. PDF | DVI | PS | No. of downloads: 321 Full access PDF | DVI | PS |

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