Pliska Studia Mathematica Bulgarica

Volume 16, 2004



C O N T E N T S


A B S T R A C T S


Study on Robustness of Strehler-Mildvan Model
Dimitar Atanasov datanasov@fmi.uni-sofia.bg

2000 AMS Subject Classification: 62F35, 62F15
Key words: robust statistics


Probabilistic Models in Cryptography and Coding Theory
Verica Bakeva verica@pmf.ukim.edu.mk

2000 AMS Subject Classification: 94A29, 94B70
Key words: quasigroups, stream cypher, tests for pseudo-random number generators, error-correcting codes.


Total Progeny in a Subcritical Branching Process with Two Types of Immigration
Maroussia Slavtchova-Bojkova bojkova@math.bas.bg
P. Becker-Kern
Kosto V. Mitov

2000 AMS Subject Classification: 60J80, 60F05
Key words: central limit theorem, total progeny, Bellman-Harris branching processes, law of large numbers, renewal processes.


On Some Concepts of Residuals
Georgi N. Boshnakov Georgi.Boshnakov@umist.ac.uk

2000 AMS Subject Classification: 60E10, 62G15, 62M20
Key words: concentration function, confidence density, confidence residual highest density region


Application of the d-fullness Technique for Breakdown Point Study of the Trimmed Likelihood Estimator to a Generalized Logistic Model
Rositsa Dimova
Neyko Neykov

2000 AMS Subject Classification: 62J12, 62F35
Key words: Breakdown Point, Subcompact Function, d-fullness, Robustness, Trimmed Likelihood Estimator, generalized logistic model.


A Statistical Approach for Multilingual Document Clustering and Topic Extraction from Clusters
Joaquim Silva mbox0106@di.fct.unl.pt
Joao Mexia
Carlos A. Coelho
Gabriel Lopes

2000 AMS Subject Classification: 62H30
Key words: cluster analysis, applied statistics, document clustering, text mining, topics extraction.


Recent Results for Supercritical Controlled Branching Processes with Control Random Functions
Miguel Gonzalez mvelasco@unex.es
Manuel Molina mmolina@unex.es
Ines del Puerto idelpuerto@unex.es

2000 AMS Subject Classification: 60J80, 60F05
Key words: controlled branching process, extinction problem, limiting behaviour.


Monte Carlo Method for Reconstruction of the Densities
Sofiya Ivanovska sofia@copern.bas.bg

2000 AMS Subject Classification: 65C05
Key words: Monte Carlo algorithms


Estimation of the Offspring Mean in a General Single-Type Size-Dependent branching process
Christine Jacob
Nadia Lalam

2000 AMS Subject Classification: 60J80,62F12, 62P10
Key words: Size-dependent branching process, Controlled branching process.


On the fractal Burgers equation with a stochastic noisy term
Ekaterina T. Kolkovska

2000 AMS Subject Classification: 60H15, 60H40
Key words: Burgers equation, white noise, weak and strong solutions, Hilbert space regularity.


Branching Particle Representations of a Class of Semilinear Equations
Jose Alfredo Lopez-Mimbela

2000 AMS Subject Classification: 60J80, 60J85
Key words: Markov branching process, semilinear partial differential equation, global and nonglobal solutions, mild solutions


Gait Measurments and Motor Recovery After Stroke
P. Mateev pmat@math.bas.bg
E. Titianova
I. Tarkka

2000 AMS Subject Classification: 62P10, 92C20
Key words: gait analysis, recovery after stroke.


A Modified Model of Risk Business
Leda D. Minkova

2000 AMS Subject Classification: 60K10, 62P05
Key words: Pуlya - Aeppli risk model, ruin probability, Cramйr - Lundberg approximation.


Limiting Distributions for Lifetimes in Alternating Renewal Processes
Kosto V. Mitov
Nickolay M. Yanev

2000 AMS Subject Classification: 60K05
Key words: alternating renewal processes, spent working time, spent waiting time, residual working time, limiting disributions, infinite mean renewal periods.


Discrete Time Bisexual Branching Processes in Varying Environments
Manuel Molina mmolina@unex.es
Manuel Mota mota@unex.es
Alfonso Ramos aramos@unex.es

2000 AMS Subject Classification: 60J80
Key words: discrete time branching processes, bisexual processes, branching processes in varying environments.


An Estimate of the Probability Pr (X < Y)
Saralees Nadarajah
Georgi K. Mitov
Kosto V. Mitov

2000 AMS Subject Classification: 33C90, 62E99
Key words: beta distribution, bootstrap confidence intervals, exponential distribution, gamma distribution, normal distribution, stress-strength, uniform disribution.


A Stochastic Approach for Finding of Semantically Related Words
Veska Noncheva bojkova@math.bas.bg
Pablo Gamallo
Alexandre Agustini

2000 AMS Subject Classification: 62P99, 68T50
Key words: syntatic context, semantic preferences, c2 goodness of fit test.


On the Equality of Sharp and Germ s -fields for Gaussian Processes and Fields
Loren D. Pitt
Raina S. Robeva

2000 AMS Subject Classification: 60G15, 60G60
Key words: Gaussian processes, Gaussian fields, germ fields, sharp Markov property, spectral syntesis.


Application of Two-phase Regression to Geotechnical Data
Eugenia Stoimenova jeni@math.bas.bg
Maria Datcheva
Tom Schanz tom.schanz@bauing.uni-weimar.de

2000 AMS Subject Classification: 62F10, 62J05, 62P30
Key words: two-phase regression, transition point,air entry value.


Simulation and Robust Modifications of Estimates in Branching Processes
Vessela Stoimenova stoimenova@fmi.uni-sofia.bg
D. Atanasova
Nickolay Yanev yanev@math.bas.bg


Multiple Dipole Source Models for Scalp-Recorded Event-Related Potentials: Example from Complex Visual Processing in the Human Brain
I.M.Tarkka

2000 AMS Subject Classification: 62P10, 92C20
Key words: electroencephalography, source modelling, visual recignition.


Classification of Chenopodium Genus Populations and Species Based on Continuous and Categorical Variables
Yanka Tsvetanova
Neli Grozeva

2000 AMS Subject Classification: 62P10, 62H30
Key words: distance between populations based on continuous and discrete variables, genus Ghenopodium, cluster analysis.


Interactive Discriminant Analysis in MATLAB
Dimitar Vandev

Key words: stepwise discriminant analysis linear quadratic MATLAB.


Comparing Several Methods of Discriminant Analysis on the Case of Wine Data
Dimitar Vandev vandev@fmi.uni-sofia.bg
Ute Romisch

2000 AMS Subject Classification: 62H30, 62J20, 62P12, 68T99
Key words: application linear quadratic discriminant analysis SVM.


Quality Improvement through Experiments with Mixtures
I.N.Vuchkov