Papers by Snejana Yordanova
WSEAS transactions on environment and development, Dec 31, 2023
Journal of automation and control, Jan 23, 2014
International Conference on Artificial Intelligence, Feb 21, 2009
Abstract: - The aim of this paper is to design a single input PI fuzzy controller for a nonlinear... more Abstract: - The aim of this paper is to design a single input PI fuzzy controller for a nonlinear and time-varying plant the biogas production rate in the anaerobic digestion of organic waste in waste water treatment. The main contributions are the design of the SI FC, the study of the ...
WSEAS Transactions on Circuits and Systems archive, 2017
WSEAS Transactions on Circuits and Systems archive, 2017
The indoor human comfort, working efficiency and health are dependent on the control of the quali... more The indoor human comfort, working efficiency and health are dependent on the control of the quality of air in a heating-ventilation and air-conditioning (HVAC) system. The aim of present paper is to improve this control considering the most important variables – the air temperature, relative humidity and concentration of carbon dioxide by applying fuzzy logic and genetic algorithms (GAs) for compensation of the variables coupling and the plant nonlinearity by energy efficient control. Two fuzzy logic controllers (FLCs) are designed, one of which two-variable based on a derived modified two-variable Takagi-Sugeno-Kang (TSK) plant model. GAs off-line parameter optimization is applied in the TSK modelling and the FLCs tuning. The FLCs are programmed in MATLABTM and in an industrial programmable logic controller and applied for the real time control of the variables of a laboratory HVAC system. The short settling time and the lack of overshoot in the transient responses of the controlle...
2005 IEEE Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications, 2005
Abstract - The aim of the present paper is to develop neuro-fuzzy models of the anaerobic organic... more Abstract - The aim of the present paper is to develop neuro-fuzzy models of the anaerobic organic digestion process in wastewater treatment from laboratory and simulated experiments accounting for the variable organic load, ambient influence and microorganisms state in MATLAB ...
Journal of Intelligent and Fuzzy Systems, 2014
Despite the new sophisticated controllers the linear PI/PID controllers keep the leading position... more Despite the new sophisticated controllers the linear PI/PID controllers keep the leading position in industrial implementations due to their simplicity, easy and well developed design and tuning, g...
Мехатроника, автоматизация, управление, Apr 12, 2023
2022 International Conference Automatics and Informatics (ICAI)
2022 International Conference Automatics and Informatics (ICAI)
Proceedings of the Technical University of Sofia, 2013
International Journal of Innovative Computing, Information and Control, 2017
The carbon dioxide concentration in rooms with varying number of people is an important safety an... more The carbon dioxide concentration in rooms with varying number of people is an important safety and comfort factor. Its control via ventilation is accompanied by two drawbacks the increased energy consumption and dependence on the quality of the fresh air used. Fuzzy logic can ensure energy efficient control of the carbon dioxide concentration. The aim of the present research is to develop a design procedure for fuzzy logic controllers (FLC), to apply it to a laboratory HVAC system and to assess its performance in real time experimentation. The main results are a design procedure for two structures of FLCs – with and without reference, real time investigation of the designed systems and comparison of their performances. Key-Words: Carbon dioxide concentration control, fuzzy logic controller design procedure, Laboratory HVAC system, energy efficiency, MATLAB TM real time experimentation
The paper suggests a simple procedure for the design of a low order robust controller for an anti... more The paper suggests a simple procedure for the design of a low order robust controller for an anti-vibration system. Anti-vibration systems are used to reduce the influence of vibrations generated in the surroundings and are essential when precise operations or measurements are required. Our design approach is based on the frequency-domain internal-model controller technique, suitably modified to account for the sensor and actuator dynamics. It uses a simplified nominal plant model with multiplicative description of both structured and unstructured plant model uncertainties. The robust performance design criterion is adopted. Simulation investigations, carried out with MATLAB and SIMULINK, are used to estimate the robustness achieved.
Proceedings of the International Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications. IDAACS'2001 (Cat. No.01EX510)
1. INTRODUCTION Robustness is the property of a system to preserve its characteristics with accep... more 1. INTRODUCTION Robustness is the property of a system to preserve its characteristics with acceptable tolerance about its desired (nominal) characteristics for a given level of model uncertainties (perturbations due to aging of material, drift of the zero and ambient influences such as ...
Parabolic partial differential equations are encountered in many diverse fields of science and en... more Parabolic partial differential equations are encountered in many diverse fields of science and engineering and even managerial sciences, like classical or quantum wave propagations, nonequilibrium statistical mechanics, probabilistic and stochastic issues. In these aspects, they are unignorable components of the modellings in research areas like chemistry, biology, and even business and economy. These types of equations are generally first order in one coordinate which may be regarded as time and second order in some other coordinates which may be called space coordinates by following the most frequently encountered cases of modelling. Their first order temporal nature enforces them to be accompanied by an initial condition while certain boundary conditions should be imposed on spatial coordinates because of the ellipticity in their operator structures on spatial coordinates. Ellipticity means boundary value problem nature and therefore the expansions on certain orthonormal basis fu...
The obtaining of an adequate estimation of the future operational behaviour of an aviation system... more The obtaining of an adequate estimation of the future operational behaviour of an aviation system when doing land testing is an essential problem. Forced testing of the corresponding basic parameter is necessary for the estimation of the technical resource left to the end of the technical exploitation. A method for solution of the problem is suggested in the paper based on the measuring and extrapolation of the time, necessary to reach a boundary value of the corresponding basic parameter. During this testing the aviation technique is exposed to some particular forcing impact. The solution of the problem is finalised to an algorithm, developed using the MATLAB software.
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Papers by Snejana Yordanova