Browsing Mathematical Sciences by Title

Alshafah, Samira (Beograd , 2018)[more][less]
Abstract: Proteins with intrinsically disordered regions are involved in large number of key cell processes including signaling, transcription, and chromatin remodeling functions . On the other side, such proteins have been observed in people suffering from neurological and cardiovascular diseases, as well as various malignancies. Process of experimentally determining disordered regions in proteins is a very expensive and long  term process. As a consequence, a various computer programs for predicting position of disordered regions in proteins have been developed and constantly improved. In this thesis a new method for determining Amino acid sequences that characterize ordered/disordered regions is presented. Material used in research includes 4076 viruses wit h more than 190000 proteins. Proposed method is based on defining correspondence between n grams (including both repeats and palindromic sequence s) characteristics and their belonging to ordered/disordered protein regions. Positions of ordered/disordered regions are predicted using three different predictors. The features of the repetitive strings used in the research include mol e fractions, fract ional differences, and z values. Also, data mining techniques association rules and classification were applied on both repeats and palindromes. The results obtained by all techniques show a high level of agreement for a short length of less than 6, while the level of agreement grows up to the maximum with increasing the length of the sequences. The high reliability of the results obtained by the data mining techniques shows that there are n grams, both repeating sequences and palindromes, which uniquely ch aracterize the disordered/ ordered regions of the proteins . The obtained results were verified by comparing with the results based on n grams from the DisProt database which contain s the positions of experimentally verified disordered regions of the protein. Results can be used both for the fast localization of disordered/ordered regions in proteins as well as for further improving existing programs for their prediction. URI: http://hdl.handle.net/123456789/4746 Files in this item: 1
ThesisSamira_Alshafah.pdf ( 3.106Mb ) 
Mušicki, Đorđe (Belgrade , 1992)[more][less]
URI: http://hdl.handle.net/123456789/511 Files in this item: 1
DjordjeMusickiD ... InGeneralizedMechanics.PDF ( 1.546Mb ) 
Ćirić, Miroslav (Beograd , 1991)[more][less]

Mijajlović, Žarko; Pejović, Nadežda (Matematički fakultet, Beograd , 2011)[more][less]

Zejak, Marija (Beograd , 2017)[more][less]

Ranković, Slavko (Belgrade , 1972)[more][less]

Putniković, Marija (Beograd , 2014)[more][less]
URI: http://hdl.handle.net/123456789/3757 Files in this item: 1
master_rad_Marija_PutnikovicR.pdf ( 2.637Mb ) 
Bilimović, Anton (Belgrade , 1977)[more][less]
URI: http://hdl.handle.net/123456789/438 Files in this item: 1
AntonBilimovicD ... ZadatakaODodiruKrugova.PDF ( 1.611Mb ) 
Živaljević, Rade (Belgrade , 1983)[more][less]

Mladenović, Monika (Beograd , 2015)[more][less]

Elfaghine, Halima (Beograd , 2016)[more][less]
Abstract: The subject of this thesis belongs the area of quality control, which represents the practical usage of statistics in following and improving the production process. In 1930 Walter Shewhart started studying quality control, based on control charts, and using statistical principles. Later on, after World War II, Edward Deming took this discipline to Japan, where it ourished. The design and the performance of control charts are the most important problems in this area. The purpose of studying the characteristics of control charts in this thesis is to compare the existing and the suggested control charts. The thesis is divided into four chapters. The rst chapter is introductory and contains motivation and basic de nitions related to this subject. In this study it is always assumed that the data are normally distributed, and that the incontrol process data are stationary and uncorrelated. Shewhart control charts and the corresponding limits are constructed in order to meet the given speci cations for the quality characteristic that we investigate. Quality control that is applied to a production process always has costs related to the control. The important parameters connected to the cost of quality control are: width of control limits k, the sample size n and the interval between the samples h. In Chapter 2 a new loss function is given, which is connected to the production process and to X−bar quality control chart. Using Matlab program for optimization, values of ^k; ^n and ^h are found, which minimize the loss function for given costs. For given values of cost, a nonlinear regression model is built using a package Sigma plot and the obtained values are compared to those obtained by numerical optimization. In Chapter 3, the time series model Yi = Xi + (1 − )Yi−1 is investigated, where 0 < B 1 is a constant, Xi are N( ; 2) distributed. Exponentially Weighted Moving Average (EWMA) control charts for this model are presented, and type I and type II errors are calculated in the case when i is large. For di erent sample sizes, the new comparison between the optimal design of the Xbar and EWMA control charts for Normally distributed quality characteristic is given, comparing the corresponding costloss functions, power functions and average run lengths. i The process of calibration is one of the methods in statistical process control, introduced for improving the quality of the products and for reducing the production costs. In Chapter 4, two new models of nonsymmetrical loss function are introduced. Here, the loss function is connected to one product under control (not to the whole sample). Using our program, written in statistical software R, the value which minimizes the expected loss for Shewhart X control chart is found. This value is used as the new central target value of the quality characteristic, that is, the production process is calibrated with this new value. The thesis ends with Conclusions, where the results of the thesis are summarized, and with some open problems to be investigated. URI: http://hdl.handle.net/123456789/4340 Files in this item: 1
Disertacija_Halima_Elfaghihe.pdf ( 1.104Mb ) 
Avramović, Katarina (Beograd , 2015)[more][less]

Vukićević, Petar (Berlin , 1894)[more][less]

Nešović, Emilija (Kragujevac, Serbia , 2011)[more][less]
Abstract: The field of research in this dissertation is consideration of different types of curves in Minkowski spaces, as well as defining the notion of hyperbolic angle between spacelike and timelike vector. The research in this dissertation is connected with the following subjects: geometry of hyperquadrics in Minkowski space, finite type submanifolds and plane Minkowski geometry. This dissertation, beside Preface and References with 56 items, consists of four chapters: 1. Curves in hyperquadrics in Minkowski spaces; 2. Classification of 2 –type curves in Minkowski nspace ; 3. Wcurves in Minkowski spacetime; 4. Hyperbolic angle between vectors. In Chapter 1 the curves lying in hyperquadrics in Minkovski 3space and Minkowski 4space are studied. More precisely, the results related with the spacelike and timelike curves lying pseudosphere in Minkowski 3space are presented. Also, the necessary and sufficient conditions for spacelike curves lying in pseudohyperbolic space in Minkowski 4space are given. Curves of finite type 2 in Minkowski nspace are studied in details in Chapter 2. Also, there are given some known results related with finite type submanifolds. In Chapter 3, Wcurves (i.e. the curves having constant all curvature functions) in Minkowski spacetime are studied and some relations between Wcurves and finite type curves are given. Finally, in Chapter 4 one of the basic notions in Lorentzian geometry is considered, i.e. hyperbolic angle between two nonnull vectors. The notion of hyperbolic angle between two timelike vectors is wellknown, so in this chapter it is defined the notion between spacelike and timelike vectors. The measure of hyperbolic angle is also defined. By using the notion of hyperbolic angle between spacelike and timelike vectors, all spacelike curves of constant precession with nonnull principal normal and all timelike curves of constant precession in Minkowski 3space are classified and their explicit parameter equations are given. URI: http://hdl.handle.net/123456789/1916 Files in this item: 1
Dokt. disertacija dr E. NešovićR.pdf ( 3.472Mb ) 
Pantić, Živadin (Belgrade)[more][less]

Bilimović, Anton (Beograd , 1962)[more][less]

Čukanović, Petar (Beograd , 2014)[more][less]
URI: http://hdl.handle.net/123456789/3912 Files in this item: 1
masterPetarCukanovic.pdf ( 1.048Mb ) 
Pejović, Tadija (BEOGRAD , 1931)[more][less]

Pejović, Tadija (SLOVO, BEOGRAD , 1933)[more][less]

Pejović, Tadija (BEOGRAD , 1935)[more][less]