DSpace Collection: Volume 2 Number 2
http://hdl.handle.net/10525/322
The Collection's search engineSearch the Channelsearch
http://sci-gems.math.bas.bg/jspui/simple-search
The Nonexistence of some Griesmer Arcs in PG(4, 5)
http://hdl.handle.net/10525/383
Title: The Nonexistence of some Griesmer Arcs in PG(4, 5)<br/><br/>Authors: Landjev, Ivan; Rousseva, Assia<br/><br/>Abstract: In this paper, we prove the nonexistence of arcs with parameters (232, 48) and (233, 48) in PG(4,5). This rules out the existence oflinear codes with parameters [232,5,184] and [233,5,185] over the field with five elements and improves two instances in the recent tables by Maruta, Shinohara and Kikui of optimal codes of dimension 5 over F5.On the Generation of Heronian Triangles
http://hdl.handle.net/10525/382
Title: On the Generation of Heronian Triangles<br/><br/>Authors: Kurz, Sascha<br/><br/>Abstract: We describe several algorithms for the generation of integer Heronian triangles with diameter at most n. Two of them have running time O(n^(2+ε)). We enumerate all integer Heronian triangles for n ≤ 600000and apply the complete list on some related problems.Improving the Watermarking Process with Usage of Block Error-Correcting Codes
http://hdl.handle.net/10525/381
Title: Improving the Watermarking Process with Usage of Block Error-Correcting Codes<br/><br/>Authors: Berger, Thierry; Todorov, Todor<br/><br/>Abstract: The emergence of digital imaging and of digital networks has made duplication of original artwork easier. Watermarking techniques, also referred to as digital signature, sign images by introducing changes that are imperceptible to the human eye but easily recoverable by a computer program. Usage of error correcting codes is one of the good choices in order to correct possible errors when extracting the signature. In this paper, we present a scheme of error correction based on a combination of Reed-Solomon codes and another optimal linear code as inner code.We have investigated the strength of the noise that this scheme is steady tofor a fixed capacity of the image and various lengths of the signature. Finally, we compare our results with other error correcting techniques that areused in watermarking. We have also created a computer program for image watermarking that uses the newly presented scheme for error correction.FLQ, the Fastest Quadratic Complexity Bound on the Values of Positive Roots of Polynomials
http://hdl.handle.net/10525/380
Title: FLQ, the Fastest Quadratic Complexity Bound on the Values of Positive Roots of Polynomials<br/><br/>Authors: Akritas, Alkiviadis; Argyris, Andreas; Strzeboński, Adam<br/><br/>Abstract: In this paper we present F LQ, a quadratic complexity bound on the values of the positive roots of polynomials. This bound is an extension of FirstLambda, the corresponding linear complexity bound and, consequently, it is derived from Theorem 3 below. We have implemented FLQ in the Vincent-Akritas-Strzeboński Continued Fractions method (VAS-CF) for the isolation of real roots of polynomials and compared its behavior with that of the theoretically proven best bound, LM Q. Experimental resultsindicate that whereas F LQ runs on average faster (or quite faster) than LM Q, nonetheless the quality of the bounds computed by both is about thesame; moreover, it was revealed that when VAS-CF is run on our benchmark polynomials using F LQ, LM Q and min(F LQ, LM Q) all three versions run equally well and, hence, it is inconclusive which one should be used in the VAS-CF method.Efficient Computing of some Vector Operations over GF(3) and GF(4)
http://hdl.handle.net/10525/379
Title: Efficient Computing of some Vector Operations over GF(3) and GF(4)<br/><br/>Authors: Bouyukliev, Iliya; Bakoev, Valentin<br/><br/>Abstract: The problem of efficient computing of the affine vector operations (addition of two vectors and multiplication of a vector by a scalar over GF (q)), and also the weight of a given vector, is important for manyproblems in coding theory, cryptography, VLSI technology etc. In this paperwe propose a new way of representing vectors over GF (3) and GF (4) andwe describe an efficient performance of these affine operations. Computingweights of binary vectors is also discussed.Analysis of the Distributions of Color Characteristics in Art Painting Images
http://hdl.handle.net/10525/378
Title: Analysis of the Distributions of Color Characteristics in Art Painting Images<br/><br/>Authors: Ivanova, Krassimira; Stanchev, Peter; Dimitrov, Boyan<br/><br/>Abstract: In this paper we study some of the characteristics of the artpainting image color semantics. We analyze the color features of differ-ent artists and art movements. The analysis includes exploration of hue,saturation and luminance. We also use quartile’s analysis to obtain the dis-tribution of the dispersion of defined groups of paintings and measure thedegree of purity for these groups. A special software system “Art Paint-ing Image Color Semantics” (APICSS) for image analysis and retrieval wascreated. The obtained result can be used for automatic classification of artpaintings in image retrieval systems, where the indexing is based on colorcharacteristics.On the Weight Distribution of the Coset Leaders of Constacyclic Codes
http://hdl.handle.net/10525/377
Title: On the Weight Distribution of the Coset Leaders of Constacyclic Codes<br/><br/>Authors: Velikova, Evgeniya; Bojilov, Asen<br/><br/>Abstract: Constacyclic codes with one and the same generator polynomial and distinct length are considered. We give a generalization of the previous result of the first author [4] for constacyclic codes. Suitable maps betweenvector spaces determined by the lengths of the codes are applied. It is proventhat the weight distributions of the coset leaders don’t depend on the wordlength, but on generator polynomials only. In particular, we prove that everyconstacyclic code has the same weight distribution of the coset leaders as asuitable cyclic code.