Browsing Doctoral Dissertations by Title
-
Marovac, Ulfeta (Beograd , 2015)[more][less]
Abstract: Proteins are signi cant biological macromolecules of polymeric nature (polypeptides), which contain amino acids and are basic structural units of each cell. Their contents include 20+3 amino acids and, as a consequence, they are presented in biological databases as sequences formed from 23 di erent characters. Proteins can be classi ed based on their primary structure, secondary structure, function etc. One of possible classi cations of proteins by their function is related to their contents in a certain cluster of ortholologous groups (COGs). This classi cation is based on the previous comparison of proteins by their similarities in their primary structures, which is most often a result of homology, i.e. their mutual (evolutionary) origin. COG database is obtained by comparison of the known and predicted proteins encoded in the completely sequenced prokaryotic (archaea and bacteria) genomes and their classi cation by orthology. The proteins are classi ed in 25 categories which can be ordered in three basic functional groups (the proteins responsible for: (1) information storage and processing; (2) cellular processes and signaling; and (3) metabolism), or in a group of poorly characterized proteins. Classi cation of proteins by their contents in certain COG category (euKaryote Orthologous Groups- KOG for eukaryotic organisms) is signi cant for better understanding of biological processes and various pathological conditions in people and other organisms. The dissertation proposed the model for classi cation of proteins in COG categories based on amino acid n-grams (sequences of n- length). The set of data contains protein sequences of genomes from 8 di erent taxonomic classes [TKL97] of bacteria (Aqui cales, Bacteroidia, Chlamydiales, Chlorobia, Chloro exia, Cytophagia, Deinococci, Prochlorales), which are known to have been classi ed by COG categories. The new method is presented, based on the generalized systems of Boolean equations, used for separation of n-grams characteristic for proteins of corresponding COG categories. The presented method signi cantly reduces the number of processed n-grams in comparison to previously used methods of n-gram analysis, iv thus more memory space is provided and less time for protein procession is necessary. The previously known methods for classi cation of proteins by functional categories compared each new protein (whose function had to be determined) to the set of all proteins which had already been classi ed by functions in order to determine the group which contained most similar proteins to the one which was to be classi ed. In relation to the previous, the advantage of the new method is in its avoidance of sequence-sequence comparison and in search for those patterns (n-grams, up to 10 long) in a protein which are characteristic of the corresponding COG category. The selected patterns are added to a corresponding COG category and describe sequences of certain length, which have previously appeared in that COG category only, not in the proteins of other COG categories. On the basis of the proposed method, the predictor for determination of the corresponding COG category for a new protein is implemented. Minimal precision of the prediction is one of the predictors arguments. During the test phase the constructed predictor shown excellent results, with maximal precision of 99% reached for some proteins. According to its properties and relatively simple construction, the proposed method can be applied in similar domains where the solution of problem is based on n-gram sequence analysis. URI: http://hdl.handle.net/123456789/4308 Files in this item: 1
phdUlfetaMarovac.pdf ( 7.954Mb ) -
Stalevski, T. Marko (Belgrade, Gent , 2012)[more][less]
URI: http://hdl.handle.net/123456789/2487 Files in this item: 1
Marko_Stalevski_doktorska_disertacija.pdf ( 6.024Mb ) -
Jaćimović, Milojica (Belgrade)[more][less]
-
Alimpić, Branka (Belgrade)[more][less]
-
Prešić, Marica (Belgrade)[more][less]
-
Popović, Georgije (Belgrade)[more][less]
-
Krstev, Cvetana (Beograd , 1997)[more][less]
-
Kubičela, Aleksandar (Belgrade , 1973)[more][less]
URI: http://hdl.handle.net/123456789/120 Files in this item: 1
phdAleksandarKubicela.pdf ( 30.99Mb ) -
Marinković, Silvana (Kragujevac, Serbia , 2011)[more][less]
Abstract: In this dissertation functions and equations in some classes of lattices such as Post algebras, Stone algebras and multiple-valued logics, are studied. The dissertation, beside Preface and References with 46 items, consists of five chapters. In Introduction some basic notations which will be used in next chapters are given. Main results on Boolean functions and equations are exposed in Chapter 2. In Chapter 3, assuming that a general solution is known, the class of reproductive general solutions of the equation in Stone algebra is described. All general solutions of equations in one variable in multiple-valued logic are described in Chapter 4. A necessary and sufficient conditions that given sequence of recurrent inequalities represents solution of some consistent Post equation are given in Chapter 5. Also, it is proved that every Post transformation is the parametric solution of some consistent Post equation. URI: http://hdl.handle.net/123456789/1842 Files in this item: 1
SilvanaMarinkovicDoktorat.pdf ( 360.3Kb ) -
Drašković, Zoran (Beograd , 1990)[more][less]
Abstract: U radu to da bude upotrebljena Galerkinova procedura za dobijanje jednatina polja tanke ljuske neuniformne debljine iz jednatina polja trodimenzionog kontinuuma. Tako to (s obzirom na to da je u [54], odnosno u (57] vet bilo reti o konstitutivnim jednacinama tanke ljuske) da bude zaokruien rad na razvoju tzv. meAovitog modela u teoriji tanke ljuske - to je model tri polja, koji predstavlja neklasidan pristup u metodi konadnih elemenata i odlikuje se nezavisnim aproksimiranjem polja pomeranja, polja deformacije i polja napona, a u cilju uzimanja u obzir i granidnih uslova na licima ljuske (tto je inade nemogute u klasidnoj metodi konadnih elemenata). Osnovna odlika pristupa u radu bite koriiCenje invarijantnih (tj. nezavisnih od izbora koordinatnog sistema) aproksimacija (i to Leiandrovim polinomima) tih polja, Itode mann koji je nov u literaturi, a treba da omoguei, s jedne strane, geometrijski doslednije, a, sa druge strane, jednostavnije dobijanje jednadina polja tanke ljuske iz trodimenzione teorije URI: http://hdl.handle.net/123456789/4092 Files in this item: 1
Jerdnacine_polja.PDF ( 1.204Mb ) -
Draškovic, Zoran (Belgrade , 1990)[more][less]
-
Stipanić, Ernest (Belgrade)[more][less]
-
Dacić, Rade (Belgrade , 1965)[more][less]
-
Mitrović, Slobodanka (Belgrade)[more][less]
-
Komarčić, Lazar (Belgrade , 1902)[more][less]
-
Lipkovski, Aleksandar (Belgrade , 1985)[more][less]
URI: http://hdl.handle.net/123456789/25 Files in this item: 1
phdAleksandarLipkovski.pdf ( 2.471Mb ) -
Miličić, Miloš (Belgrade , 1982)[more][less]
-
Malinović, Todor (Novi Sad , 1986)[more][less]
-
Obradović, Marko (Beograd , 2015)[more][less]
Abstract: First characterizations of probability distributions date to the thirties of last century. This area, which lies on the borderline of probability theory and mathematical statistics, attracts large number of researchers, and in recent times the number of papers on the subject is increasing. Goodness-of- t tests are among the most important nonparametric tests. Many of them are based on empirical distribution function. The application of characterization theorems for construction of goodness-of- t tests dates to the middle of last century, and recently has become one of the main directions in this eld. The advantage of such tests is that they are often free of distribution parametres and hence enable testing of composite hypotheses. The goals of this dissertation are the formulation of new characterizations of exponential and Pareto distribution, as well as the application of the theory of U-statistics, large deviations and Bahadur e ciency to construction and examination of asymptotics of goodness-of- t tests for aforementioned distributions. The dissertation consists of six chapters. In the rst chapter a review of di erent types of characterizations is presented, pointing out their abundance and variety. The special emphasis is given to the characterizations based on equidistribution of functions of the sample. Besides, two new characterizations of Pareto distribution are presented. The second chapter is devoted to some new characterizations of the exponential distributions presented in papers [65] and [53]. Six characterizations based on order statistics are presented. A special case of one of them (theorem 2.4.3) represents the solution of open problem stated by Arnold and Villasenor [9]. In the third chapter there are basic concepts on U-statistics, the class of statistics important in the theory of unbiased estimation. Some of their asymptotic properties are given. U-empirical distribution functions, a generalization of standard empirical distribution functions, are also de ned. The fourth chapter is dedicated to the asymptotic e ciency of statistical tests, primarily to Bahadur asymptotic e ciency, i.e. asymptotic e ciency of the test when the level of signi cance approaches zero. Some theoretical results from the monograph by Nikitin [57], and papers [61], [59], etc. are shown. In the fth chapter new results in the eld of goodness-of- t tests for Pareto distribution are presented. Based on three characterizations of Pareto distribution given in section 1.1.2. six goodness-of- t tests, three of integral, and three of Kolmogorov type, are proposed. In each case the composite null hypothesis is tested since the test statistics are free of the parameter of Pareto distribution. For each test the asymptotic distribution under null hypothesis, as well as asymptotic behaviour of the tail (large deviations) under close alternatives is derived. For some standard alternatives, the local Bahadur asymptotic e ciency is calculated and the domains of local asymptotic optimality are obtained. The results from this chapter are published in [66] and [64]. The sixth chapter brings new goodness-of- t tests for exponential distribution. Based on the solved hypothesis of Arnold and Villasenor two classes of tests, integral and Kolmogorov type, are proposed, depending on the number of summands in the characterization. The study of asymptotic properties, analogous to the ones in the fth chapter is done in case of two and three summands, for which the tests have practical importance. The results of this chapter are presented in [39]. URI: http://hdl.handle.net/123456789/4288 Files in this item: 1
phdObradovicMarko.pdf ( 789.3Kb ) -
Aranđelović, Dragoljub (Belgrade)[more][less]