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

Now showing items 281-300 of 853

Title: Behavior modeling of DC/DC buck converter Author: Panayotov, Ivan; Панайотов, Иван; Brusev, Tihomir Sashev; Брусев, Тихомир Сашев; Hristov, Marin Hristov; Христов, Марин Христов; Philipov, Philip Philipov; Филипов, Филип Филипов Date: 2007 Abstract: In this paper the implementation of analog extensions of Hardware Description Languages for behavior modeling and simulations of DC/DC converters is described. The design sequence from high level model to block level is examined. The system like description and top-down methodology are considered for behavior verification. The DC/DC converter ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Behavior modeling of elements of the structure of analog array Author: Panayotov, Ivan; Панайотов, Иван; Manolov, Emil Dimitrov; Манолов, Емил Димитров; Philipov, Philip Philipov; Филипов, Филип Филипов Date: 2007 Abstract: In this paper the way of creating universal AMS (Aanlog and Mixed Signals) HDL (Hardware Description Language) models for the elements of the structure of Field Programmable Analog Array (FPAA) chips is discussed. These are programmable chips that perform analog functions and are similar to digital FPGA (Field Programmable Gate Array) chips. ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: The little transistor and the CCAS revolution Author: Athanassov, Alexander Il.; Атанасов, Александър Ил. Date: 2007 Abstract: A scientific trip trough the years - from the birth of the first transistor to the contemporary Computers, Communications and Automation Systems (CCAS). How did the first transistor start the worldwide technology revolution – the microprocessor power, RAM, Global Net and changed the world as a whole. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Tachometer – cyclometer with programmable logic Author: Donkov, Yavor Danchev; Донков, Явор Данчев; Djamiykov, Todor Stoyanov; Джамийков, Тодор Стоянов; Rusev, Atanas Georgiev; Русев, Атанас Георгиев Date: 2007 Abstract: This paper presents the technical decision of tachometer which is realized with program logic. A distinguish feature of the suggestion is the using functional transformation of the number next impulses in order to reach a result in rpm. This way there is no need oft mathematical operations multiplication and division. The device is programmed ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Optic sensor for the joint of a walking robot Author: Djamiykov, Todor Stoyanov; Джамийков, Тодор Стоянов; Milushev, Mladen Stoilov; Милушев, Младен Стоилов; Marinov, Marin; Маринов, Марин Date: 2007 Abstract: This paper illustrates the process of study and choice regarding a sensor for motioning of walking robots. Typical for all walking machines is the need of a effective force-to-weight ratio. Based on preset parameters a sensor prototype for a sixlegged mobile robot joint had been chosen. To meet the requirements all possibilities for reaching ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Investigation of electronic instruments and methods for web-based energy management system development Author: Yakimov, Peter Ivanov; Якимов, Петър Иванов; Ovcharov, Stefan Yordanov; Овчаров, Стефан Йорданов; Tuliev, Nikolay Todorov; Тюлиев, Николай Тодоров; Balkanska, Emiliya Georgieva; Балканска, Емилия Георгиева Date: 2007 Abstract: Energy management systems exchange enormous amounts of information requiring quick access and data security. The communication and integration of data from various control centers, power plants, and substations, have become necessary. SCADA (Supervisory Control and Data Acquisition) systems are essential parts of the energy management systems ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Automated system for investigation of resistance temperature dependence of high temperature superconductors Author: Mitev, Mityo Georgiev; Митев, Митьо Георгиев; Nazarova, Elena; Назърова, Елена; Dimitrov, Emil Nikolov; Димитров, Емил Николов; Zahariev, Anton; Захариев, Антон; Georgiev, Jordan; Георгиев, Йордан Date: 2007 Abstract: The requirements to an automated system for the temperature dependence investigation of resistance in high temperature superconductors (HTSC) were analyzed. The experimental problems within a real sample are shown. The constructed system and the calibration experiments with a superconducting sample of YBa2Cu3O7-δ were described. The achieved ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Computer controlled setup for precise electrical measurements – a step towards the virtual instrumentation Author: Jivkov, Ivaylo Cankov; Живков, Ивайло; Alexandrova, Maria Petrova; Александрова, Мария Петрова; Dimov, Deyan; Димов, Деян; Kalinova, Radostina; Калинова, Радостина; Nikolova, Vessela; Николова, Весела; Denishev, Vladimir; Денишев, Владимир Date: 2007 Abstract: Virtual instrument for low current and low noise DC electrical measurement based on Keithley 617 electrometer is developed. The software consists of two parts operating in parallel threads – GUI accepting the commands from the operator and a cycle for the data acquisition and control. The device is tested by measurement of resistor with ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Hazardous gas monitoring using vi server Author: Nikolov, Georgi; Николов, Георги; Nikolova, Boyanka Marinova; Николова, Боянка Маринова; Marinov, Marin; Маринов, Марин Date: 2007 Abstract: Today there is a great deal of interest in the development of gas monitoring systems for application of gas leaks, detection of harmful gases in mines, home safety, exhaust gas monitoring etc. In all this fields of investigation, a key matter is the need of flexible and practical virtual instruments, a way to easily expose the gas sensors ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Spice modeling of taguchi sensors Author: Nikolova, Boyanka Marinova; Николова, Боянка Маринова; Nikolov, Georgi; Николов, Георги Date: 2007 Abstract: The detection and monitoring of gases with metal oxide type sensors is become a well-established practice. Modern signal processing systems are usually composed of a variety of components, electrical as well as nonelectrical (e.g. sensors and actuators, fibre optics). More complex technical systems and higher levels of integration of ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: The power quality and the measurement of harmonics Author: Stanchev, Angel; Станчев, Ангел; Ovcharov, Stefan Jordanov; Овчаров, Стефан Йорданов Date: 2007 Abstract: This paper has a purpose to explain the concept of harmonics at Low Voltage Supply Systems, which are part of the Power Quality Measurements. The work describes the main sources of the harmonic voltages and currents, the effects of harmonics, and the objectives of power quality measurement. In this work are given also the values of individual ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Dosimetric control system for a nuclear electronics training laboratory Author: Mitev, Mityo Georgiev; Митев, Митьо Георгиев; Dimitrov, Еmil; Димитров, Емил Date: 2007 Abstract: Analyzing the specific nature of working with radioactive sources in the Nuclear Electronics training laboratory we have formulated the precise requirements for the Dosimetric equipment. It has been proven that the stipulated requirements could be met by a dosimeter, functioning by the spectrum weight function method, using a NaI(Tl) ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: A simple method for stabilization of arbitrary spectra Author: Tsankov, Ludmil Todorov; Цанков, Людмил Тодоров; Mitev, Mityo Georgiev; Митев, Митьо Георгиев Date: 2007 Abstract: A method is proposed for stabilization of spectral data with arbitrary form. The method is based on the hypothesis that the successive measurements of a spectrum represent the same statistical distribution but in different X-scales. The transformation between X-scales is found by calculation of the moments of the distributions. It can be ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: GPRS system for monitoring of break - down and transient processes at current source parallel inverters Author: Veselinov, Vladislav Danchev; Веселинов, Владислав Данчев Date: 2007 Abstract: This article is dedicated to the realization of a GPRS system for monitoring of break-down and transient processes of a converter for induction heating. A structural scheme and an algorithm of work are represented and the influence of the system for control upon the security of work of the power electric device is summarized. The main ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Improving the parameters of an inductional surface hardening for one frequency and different specific powers per cm2 Author: Karamanski, Pany A.; Карамански, Пани А.; Hristov, Tsvetozar; Христов, Цветозар Date: 2007 Abstract: One of the main purposes of this article is to make a comparison among inductional heating for one working frequency of 30 kHz and different specific powers per cm 2 . Another task is to make a volume analyze of the surface and the whole volume of the hardened object and at the same time to define the quality of the hardening and the one ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Special operation features of the output transformer of series active power filters Author: Gurgulitsov, Vanjo Tomov; Гургулицов, Ваньо Томов; Antchev, Mihail Hristov; Анчев, Михаил Христов; Petkova, Mariya; Петкова, Мария Date: 2007 Abstract: This paper examines several special operation features of the output transformer included in the schematic of a series active power filter. Results enabling to found an output data to design the transformer are included. Also, graphics from a computer simulation and ocsilograms from experimental study of a laboratory model are presented. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Influence of input inductance over dynamic characteristics of single-phase shunt active power filter Author: Petkova, Mariya; Петкова, Мария; Antchev, Mihail Hristov; Анчев, Михаил Христов Date: 2007 Abstract: This paper presents the influence of input inductance over dynamic characteristics of a single-phase active power filter. Mathematical description is made and relationship among filter inductance, response time and other parameters of the system load – active power filter is derived. 3D graphics built using found formulas, simulation and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Electrical design of three-phase bridge diode rectifiers with active-capacitive load by matlab Author: Popov, Evgeniy; Попов, Евгений; Pindeva, Liliya; Пиндева, Лилия Date: 2007 Abstract: Three-phase bridge diode rectifiers with active-capacitive load can be applied for energy conversion in simple wind power generators or in controlled a.c. electrical drives with squirrel-cage induction motors. They pose specific problems to the engineers. The known methods (the ”eastern”, based on the assumption that the voltage across the ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Embedded system for video and signal processing Author: Михов, Слави Георгиев; Dimitrov, Dimitar; Димитров, Димитър; Stoyanov, Krasimir; Стоянов, Красимир; Doychev, Doycho Dimitrov; Дойчев, Дойчо Димитров Date: 2007 Abstract: Embedded microprocessor systems are becoming more and more widespread in techniques and machinery. In this paper, is made a description of a custom built system based on Analog Devices Blackfin processor family (ADSP-BF531/2/3). The system operates under Linux, which gives it flexibility and universality as an embedded solution for several ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Automatic analysis and visualization of multilead long-term ecg recordings Author: Krasteva, Vessela Tzvetanova; Кръстева, Весела Цветанова; Iliev, Ivo Tzvetanov; Илиев, Иво Цветанов Date: 2007 Abstract: Long-term ECG data collected during physical exercises (stress tests) and ordinary daily activity (holter recordings) are necessary for extended diagnosis of ischemia and transient cardiac arrhythmias. Owing to the computer-assisted systems, the cardiologist decision is considerably facilitated by fast methods for automated ECG analysis. ... Library:
TECHNICAL UNIVERSITY - SOFIA