DSpace Collection: Volume 4 Number 4
http://hdl.handle.net/10525/1540
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A 3D Model as a Tool for Increasing the Effectiveness of E-Learning
http://hdl.handle.net/10525/1607
Название: A 3D Model as a Tool for Increasing the Effectiveness of E-Learning<br/><br/>Authors: Valcheva, Donika; Todorova, Margarita; Asenov, Oleg<br/><br/>Краткий обзор (реферат): The paper proposes a 3D model which could be used as a toolfor increasing the effectiveness of e-learning. It also offers an approach forapplying this 3D model for increasing the effectiveness of e-learning. Thisapproach has methodical value in line with the idea for dynamic adjustmentof the individual learning profile of each student in order to increase thepersonalization level in the e-learning process.Using Inside-Outside Algorithm for Estimation of the Offspring Distribution in Multitype Branching Processes
http://hdl.handle.net/10525/1606
Название: Using Inside-Outside Algorithm for Estimation of the Offspring Distribution in Multitype Branching Processes<br/><br/>Authors: Daskalova, Nina<br/><br/>Краткий обзор (реферат): Multitype branching processes (MTBP) model branching structures, where the nodes of the resulting tree are particles of different types.Usually such a process is not observable in the sense of the whole tree, butonly as the “generation” at a given moment in time, which consists of thenumber of particles of every type. This requires an EM-type algorithm toobtain a maximum likelihood (ML) estimate of the parameters of the branching process. Using a version of the inside-outside algorithm for stochasticcontext-free grammars (SCFG), such an estimate could be obtained for theoffspring distribution of the process.On the Arithmetic of Errors
http://hdl.handle.net/10525/1605
Название: On the Arithmetic of Errors<br/><br/>Authors: Markov, Svetoslav; Hayes, Nathan<br/><br/>Краткий обзор (реферат): An approximate number is an ordered pair consisting of a (real)number and an error bound, briefly error, which is a (real) non-negativenumber. To compute with approximate numbers the arithmetic operationson errors should be well-known. To model computations with errors oneshould suitably define and study arithmetic operations and order relationsover the set of non-negative numbers. In this work we discuss the algebraicproperties of non-negative numbers starting from familiar properties of realnumbers. We focus on certain operations of errors which seem not to havebeen sufficiently studied algebraically. In this work we restrict ourselves toarithmetic operations for errors related to addition and multiplication byscalars. We pay special attention to subtractability-like properties of errorsand the induced “distance-like” operation. This operation is implicitly usedunder different names in several contemporary fields of applied mathematics(inner subtraction and inner addition in interval analysis, generalizedHukuhara difference in fuzzy set theory, etc.) Here we present some newresults related to algebraic properties of this operation.Solving the Task Assignment Problem with a Variable Neighborhood Search
http://hdl.handle.net/10525/1604
Название: Solving the Task Assignment Problem with a Variable Neighborhood Search<br/><br/>Authors: Kratica, Jozef; Savić, Aleksandar; Filipović, Vladimir; Milanović, Marija<br/><br/>Краткий обзор (реферат): In this paper a variable neighborhood search (VNS) approachfor the task assignment problem (TAP) is considered. An appropriate neighborhood scheme along with a shaking operator and local search procedureare constructed specifically for this problem. The computational results arepresented for the instances from the literature, and compared to optimalsolutions obtained by the CPLEX solver and heuristic solutions generatedby the genetic algorithm. It can be seen that the proposed VNS approachreaches all optimal solutions in a quite short amount of computational time.A Bayesian Spatial Mixture Model for FMRI Analysis
http://hdl.handle.net/10525/1603
Название: A Bayesian Spatial Mixture Model for FMRI Analysis<br/><br/>Authors: Geliazkova, Maya<br/><br/>Краткий обзор (реферат): We develop, implement and study a new Bayesian spatial mixturemodel (BSMM). The proposed BSMM allows for spatial structure in thebinary activation indicators through a latent thresholded Gaussian Markovrandom field. We develop a Gibbs (MCMC) sampler to perform posteriorinference on the model parameters, which then allows us to assess the posteriorprobabilities of activation for each voxel. One purpose of this articleis to compare the HJ model and the BSMM in terms of receiver operatingcharacteristics (ROC) curves. Also we consider the accuracy of the spatialmixture model and the BSMM for estimation of the size of the activationregion in terms of bias, variance and mean squared error. We perform asimulation study to examine the aforementioned characteristics under a varietyof configurations of spatial mixture model and BSMM both as the sizeof the region changes and as the magnitude of activation changes.An Algorithmic Solution for Management of Related Text Objects with Application in Phytopharmacy
http://hdl.handle.net/10525/1602
Название: An Algorithmic Solution for Management of Related Text Objects with Application in Phytopharmacy<br/><br/>Authors: Dimova, Delyana<br/><br/>Краткий обзор (реферат): This paper presents an algorithmic solution for managementof related text objects, in which are integrated algorithms for their extraction from paper or electronic format, for their storage and processing in arelational database. The developed algorithms for data extraction and dataanalysis enable one to find specific features and relations between the textobjects from the database. The algorithmic solution is applied to data fromthe field of phytopharmacy in Bulgaria. It can be used as a tool and methodology for other subject areas where there are complex relationships betweentext objects.