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Orozova D.,Burgas Free University | Sotirova E.,University Professor Dr. Assen Zlatarov Burgas
2014 18th International Symposium on Electrical Apparatus and Technologies, SIELA 2014 - Proceedings | Year: 2014

A theoretical generalized net model is proposed that describes the organization of e-learning in various subjects. Techniques for selection of an appropriate form of intervention are presented, as well as choice of alternative strategies during the training process. There are introduced criteria for assessment of the effectiveness of the learning management system with respect to the predefined training topics using intuitionistic fuzzy sets. © 2014 IEEE.


Lazarov A.,Burgas Free University | Kabakchiev H.,Sofia University | Kostadinov T.,University Professor Dr. Assen Zlatarov Burgas
Proceedings International Radar Symposium | Year: 2014

Bistatic Inverse Forward Scattering Inverse Synthetic Aperture Radar (BFISAR) concept with Digital Video Broadcast-Terrestrial (DVB-T) waveform is discussed. Geometry of BFISAR topology with stationary transmitter, receiver and kinematic of a moving target are described by vector equations. Mathematical model of BFISAR signal based on DVB-T waveform is described. Image reconstruction is applied by Fourier transform for range compression and Fourier transform for azimuth compression. Numerical experiment to verify mathematical models derived is carried out. © 2014 Warsaw University of Technology (WUT).


Lazarov A.,Burgas Free University | Minchev D.,Burgas Free University
Cybernetics and Information Technologies | Year: 2015

A nonconventional image algorithm, based on compressed sensing and l1-norm minimization in Synthetic Aperture Radar (SAR) application is discussed. A discrete model of the earth surface relief and mathematical modeling of SAR signal formation are analytically described. Sparse decomposition in Fourier basis to solve the SAR image reconstruction problem is discussed. In contrast to the classical one-dimensional definition of l1-norm minimization in SAR image reconstruction, applied to an image vector, the present work proposes a two-dimensional definition of l1-norm minimization to the image. To verify the correctness of the algorithm, results of numerical experiments are presented.


Nikolova E.,Burgas Free University | Jecheva V.,Burgas Free University
Proceedings - 8th International Conference on Database Theory and Application, DTA 2015 | Year: 2015

The present paper introduces some applications of clustering methodology, namely FLAME algorithm to the behavioral analysis of the user activities, performed by a host-based intrusion detection system. The normal and anomalous activity patterns are distinguished by 2-means clustering algorithm and separated into two non-intersecting clusters. The results of the performed simulation experiments are represented as well. © 2015 IEEE.


Georgieva P.,Burgas Free University | Popchev I.,Bulgarian Academy of Science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

There is a variety of models for portfolio selection. However, in portfolio theory applications little or no attention is paid to the cardinality problem. In this paper, an algorithm for dealing with this problem is presented. The proposed allocation algorithm is implemented in a software system, which is based on the Fuzzy Logic Q-measure Model and manages financial investments in real time. Tests on real data from Bulgarian Stock Exchange are presented as illustration to the solution. © 2013 Springer-Verlag Berlin Heidelberg.


Georgieva P.V.,Burgas Free University
2016 19th International Symposium on Electrical Apparatus and Technologies, SIELA 2016 | Year: 2016

The decisions of financial investors are often made in real-time under many constrains in an environment containing vague and imprecise information. The great amount of financial data brings additional problems in the decision making process. Currently, there are various and diverse software systems to support this process, some based on fundamental analysis and others - on technical analysis. Fuzzy rule-based systems provide the tools to overcome the above difficulties to some extent, due to the fact that dynamic models of complex and non-deterministic systems with unstable and uncertain parameters can be relatively easily. However, fuzzy systems have a serious disadvantage and it is the lack of flexibility. In this work, a hybrid genetic fuzzy system for managing financial assets and test results are presented. © 2016 IEEE.


Orozova D.,Burgas Free University | Georgieva M.,Burgas Free University
2016 19th International Symposium on Electrical Apparatus and Technologies, SIELA 2016 | Year: 2016

Theoretical generalized net (GN) model is presented, which is describing interconnection between Big Data's components. The sequence of actions, referring to creation and functioning of Big Data warehouse, as well the information flow, is defined. The model is universal and independent of Big Data's problem area. © 2016 IEEE.


Yudov D.D.,Burgas Free University | Mareva D.J.,Burgas Free University | Valchev V.C.,Varna Technical University
2016 19th International Symposium on Electrical Apparatus and Technologies, SIELA 2016 | Year: 2016

The paper presents investigation and analysis of the deviation of operating parameters of a resonant inverter for induction heating of fluids and resulting possible emergency situations (cases). Full study of 4 different emergency cases of the considered induction heating inverter is presented. The over currents through the switches are found, as well the slope of the current rising. An approach to protect the inverter in cases of emergency is proposed including an additional inductance LF in series with the input DC voltage source. Analytical derivation of the value of LF is presented, considering the power of the inverter, the switching parameters of the switches and set values of limits of the over currents. © 2016 IEEE.


Dimitrov A.,Burgas Free University | Minchev D.,Burgas Free University
2016 19th International Symposium on Electrical Apparatus and Technologies, SIELA 2016 | Year: 2016

Ultrasonic Sensor Explorer (USE) is a cheap mobile robot for mapping. Instead of expensive laser sensor, it uses cheap ultrasonic sensor HC-SR04 with range up to 4 meters. The chassis of the robot is made of ABS plastic material and it is 3D printed from a model called Mini-Me on RepRap Prusa Iteration 3 3D printer. The hardware is based on ROMEO BLE mainboard. The Software consists of two parts: firmware and application. The firmware part is an Arduino source code project, written in C++ programming language, which is deployed on the robot. The application part is Windows IoT source code, written in C# programming language, which can be run on PC, tablet, phone or ARM device. The suggested robot has been tested in the university lab environment. The presented concept proves it has a potential for SLAM. © 2016 IEEE.


Grant
Agency: Cordis | Branch: FP7 | Program: CSA-SA | Phase: FP7-PEOPLE-2011-NIGHT | Award Amount: 115.50K | Year: 2011

The project concept is based on results of previous public opinion surveys, and the wish of people Researchers Night to become a regular event in their city, where they can interact with researchers and entertain. The main goal is to enhance public recognition of researchers and their role in society and economy, to encourage young people in Bulgaria to embark on scientific career. Main objectives: -disclose talents and hidden sides of life and work of researchers, and change existing stereotypes about researchers and their profession -raise awareness on the central role of researchers and their contributions to economy and society -highlight EU emphasis on researchers and opportunities for them in the large European labour market -make science and research career attractive for young people, and especially women The target audience will be, first, young people children, teen-agers, students, and second, their parents and the public at large, including industrial and non-governmental organisations. The activities will take place in largest Bulgarian cities Sofia, Varna, Plovdiv, Rousse, Burgas and Stara Zagora, where researchers will meet people in universities, Cabinets of Curiosity, scientific cafs, Knowledge Transfer Kiosks, Innovation Fair, amuse them with verses, music life performances, experiments. European corner will inform about Marie Curie, Ernest Rutherford, EURAXESS, activities of FP7 People programme, success stories. The Communications strategy will convey two important messages: European Researchers discover the micro world and Research is a passion for a whole life. It will also look for synergy with the International Year of Chemistry, 100 anniversary of Nobel prize of Maria Curie and creation of atom model by Ruddurford, and contributions of women to science. Consortium capacity is shown already at previous Researchers Nights, and within partners collaboration in supporting researchers career, mobility and innovation.

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