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Предварителна обработка и математически анализ на PPG сигнали
Get PDFThe report presents the main research trends in the preprocessing and mathematical analysis of photoplethysmographic signals. The use of PPG in recent years has grown in parallel with the deepening penetration of modern technology in people's daily lives. At the same time, the modernization of technology has led to the miniaturization of optical sensors. A detailed overview of the state of PPG technology today and the possibilities of using PPG sensors for reporting and long-term monitoring of the health of people in their daily lives is offered. The report considers methods for noise reduction in photoplethysmographic signals based on the use of discrete wavelet transform and threshold processing of the obtained coefficients. A comparison is made between the presented methods on the basis of evaluation parameters.Научното изследване е проведено като част от проекта „Изследване на приложението на нови математически методи за анализ на кардиологични данни“ № КП-06-Н22/5 от 07.12.2018 г., финансиран от фонд „научни изследвания“
Проект за 3D мапинг "Константин Бранковяни и наследници" в галерията на църквата "Събор на Св. Архангели" в Арбанаси
Get PDFБогато културно наследство ни носи църквата "Събор на Свети Архангели Михаил и Гавраил". През XVII век тя е била използвана като енорийска църква, а през втората половина на XVIII вeк става монашеска църква. Има много публикации за историята и украсата на този храм. Въпреки популярността си, в историята на църквата остават някои неясни моменти относно най-ранния слой стенописи, открити на северната стена на кораба, както и по време на реставрационните работи през 70-те години на ХХ век, на западната стена на притвора. Все още има неразгадана мистерия – защо галерията и параклисът остават варосани? Защо не са украсени със стенописи? Идеята на този текст е да представи проект за инсталиране на два проектора в галерията на църквата, които ще представят на източната и северната стени 3D филм, разкриващ историята на Константин Бранковяну и неговите потомци. С представянето на триизмерното картографиране „Константин Бранковяни и потомци“ посетителите ще обогатят своите знания и ще бъдат подготвени да възприемат красивите иконични фрески в интериора на църквата.A rich cultural heritage has been acquired in The Archangels Michael and Gabriel church. In the 17th century it had been used as a parish church, while in the second half of the 18th century it became a monastic church. There are a lot of publications on the history and decoration of this temple. Despite its popularity, there remained some unclear points in the history of the church, concerning the earliest layer of murals. It was detected on the northern wall of the nave and also during the restoration work in the 70s of the 20th century, on west wall of the narthex. There is still a mystery unsolved – why the gallery and the chapel remained whitewashed? Why weren’t they decorated with murals? The idea of this text is to present a project for two projectors in the gallery of the church, which are going to project to the east and the north walls a 3D mapping film revealing the story of Konstantin Brankovianu and his descendants. By presenting the 3D mapping "Konstantin Brankoviani and descendants" the visitors would enrich their knowledge and be prepared to perceive the beautiful iconic murals in the interior of the church
"Абагарът" на Филип Станиславов: от амулета до гравюрата
Get PDFКнигата "Абагар", написана от епископ Филип Станиславов, е едно от най-интересните явления в българския литературен и художествен живот през XVII век. Това е първата българска печатна книга, с езикови елементи на жива, говорима българска реч. Книгата, под формата на текстов амулет, е предназначена за приобщаване на българските павликяни към католицизма. Ксилогравюрите на различни религиозни сцени и светци, с които е богато илюстрирана, стоят в основата на иконографията. Разнообразното й текстово и илюстративно съдържание, и връзката с католическата пропаганда в България, са причина за нестихващия и до днес културен и научен интерес към нея.The book "Abagar", written by Bishop Philip Stanislavov, is one of the most interesting phenomena in Bulgarian literary and artistical life during the seventeenth century. This is the first Bulgarian printed book, with linguistic elements of live, spoken Bulgarian speech. The book, in the form of a text amulet, is aimed at the involvement of Bulgarian common people with Catholicism. The engravings of various religious scenes and saints with which it is richly illustrated, are building blocks of iconography. Its diverse textual and illustrative content, as well as its connection with Catholic propaganda in Bulgaria, is the reason for the cultural and scientific interest in it that persists to this day
Ролята на мита в творчеството на Марк Ротко
Get PDFМакар и световно признат като едно от най-емблематичните имена на Абстрактния експресионизъм, Марк Ротко (1903 – 1970) не възприема себе си като абстракционист или поне не във "формалистичния" смисъл на това понятие. Известно негово изказване гласи: "Аз не съм абстракционист. Не съм заинтересован от връзката между цвета, формата и каквото и да било. Единственото ми намерение е да изразя основни човешки емоции – трагедия, екстаз, гибел и т.н." (Rothko, 2006: p. 119). В този смисъл, той вижда в мита "вечно" и "универсално" изразно средство за емоционално въздействие. Ротко е силно повлиян от "Раждането на трагедията" (1871) на Ф. Ницше, който твърди, че гръцката трагедия и трагичен мит представляват универсални човешки истини, които са безкрайни и вечни. Идеята на Ницше, че изкуството трябва да драматизира терора и борбите за съществуване, подкрепя концепцията на Ротко за художника като съвременен създател на митове (митмейкър), чиито произведения отразяват хода на човешкия дух във всичките му стремежи и превратности. В радио интервю през 1943 г. художникът казва също: "Ако заглавията (на моите картини) напомнят известните митове на древността... (аз) съм ги използвал, защото те са вечните символи, върху които трябва да се върнем, за да изразим основни психологически идеи. Те са символите на първичните човешки страхове и мотивации, без значение в коя страна или през кое време, променящи се само в детайли, но никога по същество... и съвременната психология намира, че продължават да съществуват в мечтите, нашия просто говор и нашето изкуство, за всички промени във "външните" условия на живот.". Трябва да се подчертае, че намерението на художника, позовавайки се на гръцката митология например, не е да илюстрира дадена случка, а да изрази "духа" на разказа или "духовната есенция" на мита. Въпреки, че в ранните работи на автора присъства фигуративност, с времето тя еволюира до чиста абстракция и повдига въпроса за "образ – мит" (или извежда абстрактната форма до статус на "мит"). Целта на настоящия доклад е да проследи именно този генезис в живописния език на Марк Ротко.Although globally recognized as one of the most iconic names of Abstract Expressionism, Mark Rothko (1903 – 1970) did not consider himself an abstractionist, or at least not in the "formalist" sense of the term. A famous statement of his reads: "I am not an abstractionist. I'm not interested in the relationship between color and shape and whatever. My only intention is to express basic human emotions – tragedy, ecstasy, doom, etc." (Rothko, 2006: p. 119). In this sense, he sees myth as an "eternal" and "universal" means of expressing emotional impact. Rothko was heavily influenced by F. Nietzsche's The Birth of Tragedy (1871), which argued that Greek tragedy and tragic myth represented universal human truths that were infinite and eternal. Nietzsche's idea that art should dramatize terror and struggles for existence supports Rothko's concept of the artist as a modern mythmaker, whose works reflect the course of the human spirit in all its aspirations and vicissitudes. In a 1943 radio interview, the artist also said: "If the titles (of my paintings) recall the famous myths of antiquity ... (I) have used them because they are the eternal symbols to which we must return to express basic psychological ideas. They are the symbols of primal human fears and motivations, no matter in what country or at what time, changing only in detail but never in substance... and modern psychology finds them to persist in dreams, our common speech, and our art, for all the changes in the "external" conditions of life.". It must be emphasized that the artist's intention, referring to Greek mythology for example, is not to illustrate an anecdote, but to express the "spirit" of the narrative or the "spiritual essence" of the myth. Although figurativeness was present in the author's early works, over time it evolved into pure abstraction and raised the question of "image – myth" (or brought the abstract form to the status of "myth"). The purpose of the present report is to trace precisely this genesis in the pictorial language of Mark Rothko
Acad. Blagovest Sendov – The Mathematician (and not Only): 90 Years since his Birth
No full text[Sendova Evgenija Yovkova; Сендова Евгения Йовкова]This short memoir contains some of my reflections on Acad. Blagovest Sendov’s
thoughts and experiences related to his definition of himself as a “mathematician”.
These span almost his entire life, from his early childhood to his last days. The
memories are based on what I have read and heard from him during my professional
activity (since 1969)
Ninetieth Anniversary of Professor Peter Rusev
No full text[Paneva-Konovska Jordanka; Панева-Коновска Йорданка]; [Kiryakova Virginia; Кирякова Виржиния]; [Davidov Johann; Давидов Йохан]This article is dedicated to the 90th anniversary of the distinguished Bulgarian
mathematician Professor D.Sc. Peter Rusev who is one of the first Fellows of the
Institute of Mathematics and Informatics at the Bulgarian Academy of Sciences. The
article is a short description of Professor Rusev’s scientific development and is written
to honor his contributions to complex analysis as well as his influence on establishing a school of followers in this field of research
Почти ермитови структури, туисторни пространства и хармонични изображения
No full text[Davidov Johann; Давидов Йохан]In the first part of the paper, we review the notion of an almost-complex structure and some topological obstructions for existence of such a structure. Also, we present basic facts about twistor spaces as parametrization spaces of the almostHermitian structures, i.e. orthogonal almost-complex structures, on a Riemannian (or conformal) manifold. In the second part, we consider the problem of when an almost-Hermitian structure on a Riemannian or conformal manifold determines a harmonic or pseudo-harmonic map from the manifold into its twistor space. Recent results on this problem by the author (and collaborators) are discussed mainly in the case of a four-dimensional base manifold.
Since this survey is intended for a wide audience, including students, in both parts, we emphasize mostly on elucidating examples rather than technicalities of the proofs. 2020 Mathematics Subject Classification: 53C43, 58E20, 53C15
Enumeration of Optimal Equidistant Codes
Get PDFProblems of search and enumeration of binary and ternary equidistant codes are considered in the paper. We investigate some combinatorial algorithms and develop specialized computer packages to find non-equivalent optimal binary and ternary equidistant codes for 3 ≤ d ≤ n ≤ 9.National Science Fund of Bulgaria (scientific project “Digital Accessibility for People with Special Needs: Methodology, Conceptual Models and Innovative Ecosystems”), Grant Number KP-06-N42/4, 8 December 2020
Two Approaches to the Traffic Quality Intuitionistic Fuzzy Estimation of Service Compositions
Get PDFRecently, intuitionistic fuzzy pairs have been used as uncertainty estimations of the request services in service systems. In the present paper, three intuitionistic fuzzy characterizations of virtual service devices are specified: intuitionistic fuzzy traffic estimation, intuitionistic fuzzy flow estimation and intuitionistic fuzzy estimation about probability. Discussed herein are two approaches to the intuitionistic fuzzy estimation of the uncertainty of compositions of services. One of the approaches is based on the definitions of the intuitionistic fuzzy pairs for one service device. The other approach is based on the aggregation operators over intuitionistic fuzzy pairs. A total of six intuitionistic fuzzy estimations of the uncertainty of comprise service device are proposed. The proposed uncertainty estimations allow for the definition of new Quality of Service (QoS) indicators and can be used to determine the quality of service compositions across a wide range of service systems.Bulgarian National Science Fund grant number KP-06-N52/2 (“Perspective Methods for Quality Prediction in the Next Generation Smart Informational Service Networks”)
Short Proofs of Explicit Formulas to Boundary Value Problems for Polyharmonic Equations Satisfying Lopatinskii Conditions
Get PDFThis paper deals with Lopatinskii type boundary value problem (bvp) for the (poly) harmonic differential operators. In the case of Robin bvp for the Laplace equation in the ball 1 a Green function is constructed in the cases >0, ∉− , where c is the coefficient in front of u in the boundary condition ∂ ∂ + =
. To do this a definite integral must be computed. The latter is possible in quadratures (elementary functions) in several special cases. The simple proof of the construction of the Green function is based on some solutions of the radial vector field equation Λ + =
. Elliptic boundary value problems for Δ =0
in 1 are considered and solved in Theorem 2. The paper is illustrated by many examples of bvp for Δ =0, Δ2 =0 and Δ3 =0 in 1 as well as some additional results from the theory of spherical functions are proposed