Institute of Mathematics and Informatics
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Анализ на апостериорната грешка за апроксимация с редуциран базис на две параболични задачи за растеж на тумори
Get PDF[Rashkov Peter; Рашков Петър]This work presents a theoretical analysis for an a posteriori error estimate for a reduced-basis approximation of the solution for two parametrised parabolic problems. Their motivation is in mathematical oncology and they describe a) a model for brain tumour growth [14] and b) a model for phenotype evolution of a tumour based on [3, 13], with the free parameter being the therapeutic dose. The discretisation of the problems in space is realised by the finite element method, and the numerical integration uses a first-order IMEX scheme due to model b) being a integro-differental problem. The obtained a posteriori error estimate for the approximation error between the numerical solution and the reduced basis solution gives the opportunity for constructing a reduced basis for the solution manifold by combining a proper orthogonal decomposition of the temporal trajectories and a greedy algorithm over the parameter range, as has been done in the case of explicit or implicit integration of linear parabolic problems [8, 10]
Разработване на онтология в областта на хуманитаристиката
Get PDFСъхранeнието и разпространението на знания за културно-историческите и природни обекти в България е от изключително значение. В тази връзка във Факултета по математика и информатика на Пловдивския университет се разработва проект, свързан с имплементацията на интелигентен туристически екскурзовод, който по зададени критерии от туриста, генерира виртуални или туристически реални маршрути. В статията ще бъде представена част от базата знания на туристическия екскурзовод, а именно онтология, описваща богатството на българската литература. Представена е структурата на онтологията, базовите аксиоми и зависимости между основните концепции, а също така идентичностите за отделните концепции в онтологията.The preservation and dissemination of knowledge about cultural, historical, and natural sites in Bulgaria is extremely important. In this regard, the Faculty of Mathematics and Informatics of Plovdiv University is developing a project related to the implementation of an intelligent tourist guide, which, according to the tourist’s criteria, generates virtual or real tourist routes. The article will present part of the knowledge base of the tourist guide, namely an ontology that describes the richness of Bulgarian literature. The structure of the ontology, the basic axioms, and dependencies between the basic concepts, as well as the identities of the individual concepts in the ontology are presented
Новооткрита монашеска скална килия между манастирските скални комплекси "Архангела" и "Кръщелнята" от Ивановските скални манастири (нов поглед към обхвата на Великата лавра "Архангела" при с. Иваново)
Get PDFПри поредните теренни проучвания за обследване на района на Ивановските скални манастири, проведени в края на 2020 и началото на 2021 год. бяха открити неизвестни до момента, скално изсечени и оформени пещери и скални ниши с различно предназначение. Сред локализираните нови обекти се открои сравнително голяма скална ниша с прилежащи към същата различни скалноизсечени елементи, допълващи пространствено и функционално монашеското жилище. Общият план, новите елементи на строителство и оформление обогатяват представите за устройството на монашеските скални обители в Поломието. Местоположението на обекта, свързаността му с останалите антропогенизирани части в района и характерните му особености дават представа за едни нови виждания за обхвата и устройството на Великата Лавра "Св. Архангел Михаил" при с. Иваново, община Русе.In another terrain research for the examination of the region around the Ivanovo Rock-hewn monasteries, conducted at the end of 2020 and at the beginning of 2021, well-shaped rock-hewn caves and rock niches with a different designation were discovered, which have now been known so far. Among the newly discovered objects, one relatively big rock niche, having different rock-hewn elements adjacent to it, stood out. Those elements complemented the monk dwelling with respect to space and designation. The general layout, the new construction elements enrich the concept about the structure of the monk rock-hewn dwellings in the Polomie. The location of the object, its linkage to the rest of the anthropogenic parts of the region and its characteristic features give us a new idea about the range and structure of the Great monastery "St Archangel Michael" at the Ivanovo village, municipality of Russe
Integer Codes Correcting Asymmetric Errors in Nand Flash Memory
Get PDFMemory devices based on floating-gate transistor have recently become dominant technology for non-volatile storage devices like USB flash drives, memory cards, solid-state disks, etc. In contrast to many communication channels, the errors observed in flash memory device use are not random but of special, mainly asymmetric, type. Integer codes which have proved their efficiency in many cases with asymmetric errors can be applied successfully to flash memory devices, too. This paper presents a new construction and integer codes over a ring of integers modulo A=2^n+1 capable of correcting single errors of type (1,2),(±1,±2), or (1,2,3) that are typical for flash memory devices. The construction is based on the use of cyclotomic cosets of 2 modulo A. The parity-check matrices of the codes are listed for n≤10
Series in Le Roy Type Functions: Theorems in the Complex Plane
Get PDFSeries defined by means of the Le Roy type functions are considered in this paper. These series are studied in the complex plane and their behaviour is investigated ‘near’ the boundaries of their domains of convergence.Bilateral Res. Projects ‘Operators, differential equations and special functions of Fractional Calculus – numerics and applications’ between BAS and SANU and ‘Analysis, Geometry and Topology’ between BAS and MANU; COST program, COST Action CA15225 ‘Fractional’
Dynamics of Modified Lotka-Volterra Model with Polynomial Intervention Factors. Methodological Aspects. III.
Get PDFIn the present article is considered a modification of the classical Lotka–Volterra model. The ’input functions α(t) and γ(t) are algebraic polynomials of degree n, α(t) is monotonically increasing (with ”saturation”) and γ(t) > 0 is monotonically decreasing in the considered interval. This model is very sensitive with respect to the coefficients of the polynomials a_i and b_i. Therefore it is attractive for conducting computer simulations, including other modified predator-prey models and activator-inhibitor mechanisms. Numerical examples, illustrating our results are given using CAS Mathematica.Grant No BG05M2OP001-1.001-0003,
financed by the Science and Education for Smart Growth Operational Program (2014-
2020) and co-financed by the European Union through the European structural and
Investment funds; Grant No KP-06N42-2/27.11.2020, financed by Bulgarian National Science Fund
Изменение на Шумановите честоти
Get PDFThis article presents the origin of Schumann frequencies, their measurement and monitoring. The results of their measurements are presented and their diurnal and seasonal variations are analyzed. Application areas of Schumann frequencies are discussed
Implementation of an Ontology-Based Decision Support System for Dietary Recommendations for Diabetes Mellitus
Get PDFAlong with the massive influence of computing technologies in medical research and practice, the wide generation of patient, clinical and lab test data makes the assistance of intelligent information systems a very important factor for correct therapy, surveillance and advising of the patients. In this context decision support systems play an increasingly important role in medical practice. The implementation of a decision support system (DSS) in diabetes treatment and in particular in organizing an improved regime of food balance and patient diets is the target area of the presented study. Based on the recently created Diabetes Mellitus
Treatment Ontology (DMTO), our DSS for dietary recommendations generates broader and more precise advices to patients with a known clinical history and lab test profiles. These recommendations are rule-based decisions derived using the DMTO subontologies for patient’s lifestyle improvement and the data from the patient records.National Scientific Program “eHealth” in Bulgaria. Methodological support was received from Project BG05M2P001-1.001-0004
“Universities for Science, Informatics and Technologies in the e-Society (UNITe)”
funded by Operational Program “Science and Education for Smart Growth” co-funded
by European Regional Development Fund
За прабългарските кръстовидни храмове?
Get PDFПредмет на статията са две сгради с кръстовиден план, намиращи се в Плиска. След разрушаването на едната сграда върху нейните останки е построена Голямата базилика. Разгледани са строителната история на кръстовидната сграда, надстройката ѝ, строителните периоди, предназначението ѝ според отделните изследователи – гробница от ранновизантийския период, прабългарски езически храм, мавзолей на българските канове, църква, кръщелна или мартирий, съоръженията, които са функционално свързани с нея, съдбата ѝ след приемането на християнството. Върху основите на втората кръстовидна сграда е изградена църква № 3. Затова нейният проучвател е на мнение, че тя е била прабългарски храм. Повечето археолози смятат, че само постройките с план от вписани четириъгълници са били прабългарски езически светилища и в своите разработки въобще не споменават за тази сграда, и не коментират възможността тя да е представлявала капище. Р. Рашев ни припомни този позабравен паметник. Други археолози обаче считат, че вероятно двете кръстовидни сгради са функционирали като капища и образуват нова група светилища с кръстовиден план освен групата от храмове с план, състоящ се от вписани четириъгълници.The article examines two buildings with a cross-shaped plan, located in Pliska. After the destroying of one of the buildings, the Great Basilica was built on its remains. The report includes all the opinions of researchers about the purpose of the cross-shaped building - a tomb from the early Byzantine period, a protobulgarian pagan temple, a mausoleum of the Bulgarian Khans, a church, a baptistery, a martyrium. Its construction history, superstructure, construction periods, facilities that are functionally related to it, its fate after the adoption of Christianity are examined. A church was built on the foundations of the second crossshaped building. Therefore, her researcher is of the opinion that it was a protobulgarian temple. Most archaeologists believe that only the buildings with a plan of inscribed quadrilaterals were protobulgarian pagan temples and in their works do not mention this building at all and do not comment on the possibility that it was a pagan temple. R. Рашев reminded us of this forgotten monument. Other archaeologists also believe that the two cross-shaped buildings were probably pagan temples and formed a new group of cross-shaped temples in addition to the group of temples with a plan consisting of inscribed quadrilaterals
Robotz India - Increasing Innovation in Schools
Get PDFThe mission is to nurture a creative child through new technologies such as computing, sensors and artificial intelligence. School Children explored the wonderful science and computing through handson robots building and programming. We strive to develop the scientists and engineers of tomorrow with foundations of STEM learnt in a practice school methodology