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Proceedings of the Technical university of Sofia, 1995 -: Recent submissions

Now showing items 321-340 of 853

Title: Трифазни математически модели на агрегати за собствени нужди в електрическите централи с различни специфични особености Author: Крумов, Андрей; Krumov, Andrej Date: 2007 Abstract: The three-phase models are realized with momentary values of the electric quantities. This enables study of all types of slow and fast transients – starting of aggregates, operation at change of the load, supply voltage or its frequency, incomplete phase regimes, short circuits, etc. In the electric power stations, the driving of mechanisms ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Трифазен математически модел за изследване на режимите на работа на системите за собствени нужди в електрическите централи Author: Крумов, Андрей; Krumov, Andrej Date: 2007 Abstract: The auxiliary systems are built with single sectioned busbar system. For reducing the short-circuit currents transformers with separate windings are used. The loads are distributed almost uniformly between the main sections. This enables the model study of the regimes of auxiliaries to be limited to one section. The three-phase model of a ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Подходи за определяне на индуктивността на намагнитващия контур на асинхронен двигател Author: Михов, Михо; Mihov, Miho; Рац, Емил; Ratz, Emil; Рачев, Емил; Rachev, Emil; Рац, Роберт; Ratz, Robert Date: 2007 Abstract: The report covers comparison between the capabilities of three approaches for determination of the magnetizing mutual inductance in the asynchronous motor;Experimental approach by means of the idling and locked rotor experiments results,Numerical approach using the final elements analysis method in the FEMM program environment, Static ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Относно отчитането на насищането на магнитната среда при безсензорно векторно управление на асинхронни двигатели Author: Рац, Емил; Ratz, Emil; Михов, Михо; Mihov, Miho; Рац, Роберт; Ratz, Robert; Рачев, Емил; Rachev, Emil Date: 2007 Abstract: The paper is focused on the expression of the mutual inductance, L f m mr ( ) N  I , L f m ms ( ) N  I , L f m m ( ) N  I in order to take into account the squirrel cage asynchronous motor magnetic core saturation. The conducted analytical, experimental and simulation investigations in Matlab and FEMM environments show that adequate ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Числен подход за построяване на P-Q диаграми на явнополюсни синхронни генератори Author: Михов, Михо; Mihov, Miho; Сотиров, Димитър; Sotirov, Dimitar; Ризов, Пламен; Rizov, Plamen; Господинов, Васил; Gospodinov, Vasil; Баташки, Стоян; Batashki, Stoyan Date: 2007 Abstract: The numerical approach is offered for construction P-Q diagrams of hydrogenerators with different limits. The needed incoming data is usually provided by the producer of the machines. At the calculations it is supposed sanely that the iron cores are low saturated and the coefficient in saturation on d and q axes is practically the same. The ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Сравнителен анализ на характеристики в установен режим при честотно и векторно управление на асинхронен двигател Author: Рац, Емил; Ratz, Emil; Рачев, Емил; Rachev, Emil Date: 2007 Abstract: In this paper a comparative analysis of scalar and vector control method of induction motor is presented. Some steady-state characteristics are considered: the overloading ability is compared in both scalar control and rotor flux oriented vector control technique taking to account not to exceed motor’s rated current and voltage. Various ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Влияние на организирано подавания въздух, върху процесите в пещната камера на котел № 10 в ТЕЦ “Марица Изток 2” Author: Игнатов, Борислав; Ignatov, Borislav; Бонев, Бончо; Bonev, Boncho; Тотев, Тотьо; Totev, Totyo Date: 2007 Abstract: Some of the factors that have big influence on the burning processes are the quantity of the oxidant and the place where it is fed. In the present article are made investigations of the behavior of the torch in the burning chamber of boilers type P-62 №10 by different amounts of air in the basic burner, using the simulation modeling. The ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Влияние на експлоатационните характеристики на прахоприготвящите системи, върху процесите в пещната камера на котел №10 в ТЕЦ “Марица Изток 2” Author: Игнатов, Борислав; Ignatov, Borislav; Тотев, Тотьо; Totev, Totyo; Бонев, Бончо; Bonev, Boncho Date: 2007 Abstract: The characteristics of the coal-dust preparation systems and the mills productivity render a big influence over the process in the steam generators. The aim of that investigation is to value their influence and to determinate their effect on the burning process. It is possible to influence with them direct over the burning process in the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Сегментиране на ръкописни думи с комбиниране на самоорганизиращи се невронни мрежи и евристични правила Author: Драганов, Иво; Draganov, Ivo; Попова, Антоанета; Popova, Antoaneta Date: 2007 Abstract: In this paper we present a new algorithm for handwritten word segmentation from images based on a combined method using self-organizing neural networks and heuristic rules. The suggested algorithm aims the usage of minimal number of segmentation points with as little heuristic rules as possible but preserving good accuracy for the segmentation ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Приложение на wavelet трансформацията за декомпозиция на дискретни аудио сигнали Author: Момчеджиков, Михаил; Momtchedjikov, Mihail; Буджашки, Менде; Bujashki, Mende; Миронов, Румен; Mironov, Rumen Date: 2007 Abstract: The Wavelet Transform (WT) is a transformation that can be used to analyze and represent the temporal and spectral properties of non-stationary signals like audio. The combination of time and frequency localization is important for coding audio signals. The WT yields a compact representation of signals without an a priori knowledge of signal ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Техники за 3D визуализация на терапевтично ниско-честотно магнитно поле Author: Димитрова, Виргиния; Dimitrova, Virginiya Date: 2007 Abstract: The article presents algorithms and techniques for 3d visualization of low-frequency magnetic field, generated by a pair of cylindrical coils placed on the surface of human body parts. Two different approaches for visualization of the field distribution are discussed for the cases of: coils with co-planar Z-axis and coils with arbitrary ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Тенденции в развитието на ICT-бранша и потенциалната реализуемост на бъдещите млади специалисти Author: Георгиев, Веселин; Gueorguiev, Vesselin; Иванов, Иван; Ivanov, Ivan; Георгиева, Десислава; Georgieva, Desislava Date: 2007 Abstract: The last 10-15 years of Bulgarian higher education changed lecturers’ point of view about the main question “What is the students’ education – social event or business”. This is the fundament on what is based the answer of the question “Who is the recipient of education results – the students or companies hiring that students”. Now we are ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Метод за валидиране на входни данни при web базирани приложения Author: Ганчева, Веска; Gancheva, Veska Date: 2007 Abstract: The paper presents an approach for fully implementation of a data validation in Web applications. This approach separates the implementation of common data validation reasoning code from the business rules and criteria data used to validate user input. Suggested approach is realized as fourth layer with the possibility to validate data from ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Автоматизирана система за проучване на студентското мнение Author: Желев, Господин; Jelev, Gospodin; Минкова, Йоана; Minkova, Yoana; Минковска, Даниела; Minkovska, Daniela Date: 2007 Abstract: The article presents the results of students’ opinion research concerning the quality and effectiveness of the educational process. The research is carried out by means of computerized inquiries, based on “6-models” standard of TSS. The inquiries explore the students’ motivation, educational environment factors, teaching technology and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: ERP базирана електронна търговия Author: Маринов, Орлин; Marinov, Orlin; Цанкова, Румяна; Tsankova, Roumiana Date: 2007 Abstract: Different Forms e- commerce requirements are discussed in this paper. Bulgarian and foreign Sites Experience is investigated. In this way the functional Characteristics of the different commerce Forms and the Possibilities of the advanced information Technologies are satisfied. Flexible architecture Modules for Satisfaction of these ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Паралелен парсинг механизъм за ускоряване на sax парсери Author: Георгиев, Божидар; Georgiev, Bozhidar Date: 2007 Abstract: This paper presents a non-traditional approach for acceleration of parsing process in modern W3C-standard XML. Here are described both possibilities for faster parsing procedures- conventional SAX architecture and the parallel parsing concept proposed in this paper. In the article is proven that the parallel parser is faster than traditional ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Повишаване на коефициента на справедливост при клетъчни мрежи за пренос на медицински сигнали и данни Author: Христов, Валентин; Hristov, Valentin; Димитров, Димитър; Dimitrov, Dimiter Date: 2007 Abstract: Improving throughput and fairness in Cellular Data Networks is a problem of present interest. Non high throughput and unfairness of data streams and sharing the network resources greatly limit putting into practice and the commercial market wining of such networks and technologies. In article are considered main realized in practice way of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Генериране на асиметрични периодични сигнали на базата на свързани резонансни системи Author: Паралиев, Мартин; Paraliev, Martin; Димитров, Димитър; Dimitrov, Dimiter Date: 2007 Abstract: The coupled resonant systems are an attractive solution if a good energy transfer rate is required and low coupling factor is available. However, these systems have narrow bandwidth that makes them less applicable for signals with more complex harmonic structure. Their analysis utilizes their application for asymmetric periodical signals ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Електрохимично израстване на топологично структурирани дебели слоеве Author: Йорданов, Никола; Yordanov, Nikola; Филипов, Филип; Philippov, Philip; Видеков, Валентин Христов; Videkov, Valentin Hristov; Арнаудов, Радосвет; Arnaudov, Radosvet Date: 2007 Abstract: In the present report some basic methods in the electrochemical plating of copper or some other metal layers, at structured topology layout, are revealed. The given arbitrary topology layout could be structured by means of additive or subtractive methods. Technology routes for electrochemical growth of metal structures, as well as their ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Алгоритъм за прогнозиране с невронни мрежи Author: Винчева, Илияна; Vincheva, Iliana Date: 2007 Abstract: Neural networks are good at classification, forecasting. Forecasting is often used in the decision making process. In this article is built a seven-step neural network forecasting model. Pre and post data processing/analysis skills, data sampling, training criteria and model recommendation will also be covered in this article. Library:
TECHNICAL UNIVERSITY - SOFIA