Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771588
Miroslav Marinov, I. Valova, Yordan Kalmukov
Content-based image retrieval methods in present days are used in modern social media and search engines. They give techniques for analyzing, organizing, processing and searching through million images uploaded daily in the internet. For that reason, searching is the most critical process in CBIR. It should be accurate and complete in reasonable amount of time. Proper metadata should be extracted from the images and used to meet the performance requirements. From the other hand, to meet the subsequent processing this metadata should be indexed and stored in appropriate way.This paper describes some of the most popular image extraction and analysis systems known as Content Based Image Retrieval Systems (CBIR). It reveals how examined different CBIR systems work and how closer are generated similarity results. At the end, information is summarized, and conclusions are made regarding existing solutions and methods used in these applications.
{"title":"Comparative Analysis of Content-Based Image Retrieval Systems","authors":"Miroslav Marinov, I. Valova, Yordan Kalmukov","doi":"10.1109/ELMA.2019.8771588","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771588","url":null,"abstract":"Content-based image retrieval methods in present days are used in modern social media and search engines. They give techniques for analyzing, organizing, processing and searching through million images uploaded daily in the internet. For that reason, searching is the most critical process in CBIR. It should be accurate and complete in reasonable amount of time. Proper metadata should be extracted from the images and used to meet the performance requirements. From the other hand, to meet the subsequent processing this metadata should be indexed and stored in appropriate way.This paper describes some of the most popular image extraction and analysis systems known as Content Based Image Retrieval Systems (CBIR). It reveals how examined different CBIR systems work and how closer are generated similarity results. At the end, information is summarized, and conclusions are made regarding existing solutions and methods used in these applications.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114291067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771557
B. Evstatiev, N. Evstatieva, Dimitar Trifonov
In this study is presented the development of a virtual laboratory for the "Logic design" course, using the Engine for Virtual Electrical Engineering Equipment (EVEEE). The basic logic gates (AND, OR, NAND, NOR, NOT) and combinational logic (decoder and multiplexer) are modeled as analog devices, with inputs and outputs. Each input is represented with a 1 MΩ resistor, and each output is a nonlinear dependent source, both connected to ground. The logic of the dependent source is implemented using SPICE’ conditional logic. To improve the traceability of the logic circuit, each input/output socket has a corresponding virtual light emitting diode, which visualizes its state – digital one or digital zero.
{"title":"Development of a Virtual Laboratory in Logic Design","authors":"B. Evstatiev, N. Evstatieva, Dimitar Trifonov","doi":"10.1109/ELMA.2019.8771557","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771557","url":null,"abstract":"In this study is presented the development of a virtual laboratory for the \"Logic design\" course, using the Engine for Virtual Electrical Engineering Equipment (EVEEE). The basic logic gates (AND, OR, NAND, NOR, NOT) and combinational logic (decoder and multiplexer) are modeled as analog devices, with inputs and outputs. Each input is represented with a 1 MΩ resistor, and each output is a nonlinear dependent source, both connected to ground. The logic of the dependent source is implemented using SPICE’ conditional logic. To improve the traceability of the logic circuit, each input/output socket has a corresponding virtual light emitting diode, which visualizes its state – digital one or digital zero.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123896735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771667
E. Kurbatova, E. Kuschenko, M. Sysoev, Andrey DROZDOV, P. Dergachev, P. Kurbatov
This paper presents the results of modeling and experimental study of a tooth zone of linear electric machines with high-temperature (HTS) elements. In this work, we consider the using of HTS bulks as a diamagnetic material for regulating of reluctance of the tooth zone. It focuses on the ability of HTS elements to change the way of magnetic flux lines in a magnetic system and their influence on an electromagnetic force.
{"title":"Using of the Diamagnetic Properties of HTS for Magnetic systems of Linear Electric Machines","authors":"E. Kurbatova, E. Kuschenko, M. Sysoev, Andrey DROZDOV, P. Dergachev, P. Kurbatov","doi":"10.1109/ELMA.2019.8771667","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771667","url":null,"abstract":"This paper presents the results of modeling and experimental study of a tooth zone of linear electric machines with high-temperature (HTS) elements. In this work, we consider the using of HTS bulks as a diamagnetic material for regulating of reluctance of the tooth zone. It focuses on the ability of HTS elements to change the way of magnetic flux lines in a magnetic system and their influence on an electromagnetic force.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116610425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771640
B. Evstatiev, Dimcho V. Kiriakov, Dimitar Trifonov
The digitalization of the contemporary education strongly depends on the development of virtual and remote laboratories. Before a virtual copy of a real lab is created, it should be modelled in accordance with the requirements of the virtual environment. In this study is created a simple and accurate model of a nonlinear inductor, based on voltagecontrolled nonlinear current sources. Their amplitudes and phase-shifts are approximated with a linear model as a function of the supplied sinusoidal voltage amplitude. The model showed very high accuracy with coefficients of determination above 0.98 for the amplitudes and above 0.93 for the phase shifts.
{"title":"Model for Simulation of Nonlinear Inductors in Virtual Environments","authors":"B. Evstatiev, Dimcho V. Kiriakov, Dimitar Trifonov","doi":"10.1109/ELMA.2019.8771640","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771640","url":null,"abstract":"The digitalization of the contemporary education strongly depends on the development of virtual and remote laboratories. Before a virtual copy of a real lab is created, it should be modelled in accordance with the requirements of the virtual environment. In this study is created a simple and accurate model of a nonlinear inductor, based on voltagecontrolled nonlinear current sources. Their amplitudes and phase-shifts are approximated with a linear model as a function of the supplied sinusoidal voltage amplitude. The model showed very high accuracy with coefficients of determination above 0.98 for the amplitudes and above 0.93 for the phase shifts.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123214089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771496
Gergana Vacheva, V. Dimitrov, N. Hinov
The present paper study modelling, design consideration and control of a bidirectional DC/DC buck-boost converter for application in hybrid and electric vehicles. The proposed model includes electric motor, dynamics of the vehicle and theirs control. A mathematical model of the DC/DC buck-boost converter is described with differential equations during the both the boost and buck regions of operation. The control system is created and realized with proportional-integral regulator. The proposed solution is realized in visual environment MATLAB/Simulink. The obtained results demonstrates that the proposed solution is suitable for different electric vehicles applications.
{"title":"Modelling and Control of Bidirectional Buck-Boost Converter for Electric Vehicles Applications","authors":"Gergana Vacheva, V. Dimitrov, N. Hinov","doi":"10.1109/ELMA.2019.8771496","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771496","url":null,"abstract":"The present paper study modelling, design consideration and control of a bidirectional DC/DC buck-boost converter for application in hybrid and electric vehicles. The proposed model includes electric motor, dynamics of the vehicle and theirs control. A mathematical model of the DC/DC buck-boost converter is described with differential equations during the both the boost and buck regions of operation. The control system is created and realized with proportional-integral regulator. The proposed solution is realized in visual environment MATLAB/Simulink. The obtained results demonstrates that the proposed solution is suitable for different electric vehicles applications.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"452 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115290814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-06DOI: 10.1109/ELMA.2019.8771525
N. Djagarov, Z. Grozdev, G. Enchev, J. Djagarova
Induction motors are primarily used as ship electric drives. Due to the autonomy of ship electrical systems, the requirements for reliable operation are higher than those of coastal systems. Particularly great are the requirements for propulsion electric motors and drives. Centralized control systems are implemented (supervisory control and data acquisition - SCADA). The article provides a classification and an overview of the causes of engine failure, fault indicators, methods and means for identifying and predicting the failure modes of induction drives.
{"title":"Ship’s Induction Motors Fault Diagnosis","authors":"N. Djagarov, Z. Grozdev, G. Enchev, J. Djagarova","doi":"10.1109/ELMA.2019.8771525","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771525","url":null,"abstract":"Induction motors are primarily used as ship electric drives. Due to the autonomy of ship electrical systems, the requirements for reliable operation are higher than those of coastal systems. Particularly great are the requirements for propulsion electric motors and drives. Centralized control systems are implemented (supervisory control and data acquisition - SCADA). The article provides a classification and an overview of the causes of engine failure, fault indicators, methods and means for identifying and predicting the failure modes of induction drives.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"41 3-4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114027475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ELMA.2019.8771548
F. Magdy, D. Ibrahim, W. Sabry
Most of the previous researches which intended with the subject of virtual power plants (VPPs), focused on the study of VPPs from economical point of view: auctions, bidding, trading, markets, pricing, cost, profit, benefits, risk, investors … etc. Merely conjecture, all the VPPs' models presented are financial and economical models, with no one prescribed electrical model. In this paper, a generic VPP will be proposed and considered for the study. The proposed generic VPP will be modeled with a novel Electro-Economical Model (EEM). The proposed model was constructed on three steps: construction of electrical model, construction of economical model, and combining both electrical and economical models to form EEM of the proposed generic VPP. The proposed generic VPP consisting of four basic components: dispatchable power plant(s), flexible load(s), storage unit(s), and stochastic generating unit(s); was illustrated. This system model has been simulated. All simulation results will be demonstrated and discussed.
{"title":"Virtual Power Plants Modeling and Simulation using Innovative Electro-Economical Concept","authors":"F. Magdy, D. Ibrahim, W. Sabry","doi":"10.1109/ELMA.2019.8771548","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771548","url":null,"abstract":"Most of the previous researches which intended with the subject of virtual power plants (VPPs), focused on the study of VPPs from economical point of view: auctions, bidding, trading, markets, pricing, cost, profit, benefits, risk, investors … etc. Merely conjecture, all the VPPs' models presented are financial and economical models, with no one prescribed electrical model. In this paper, a generic VPP will be proposed and considered for the study. The proposed generic VPP will be modeled with a novel Electro-Economical Model (EEM). The proposed model was constructed on three steps: construction of electrical model, construction of economical model, and combining both electrical and economical models to form EEM of the proposed generic VPP. The proposed generic VPP consisting of four basic components: dispatchable power plant(s), flexible load(s), storage unit(s), and stochastic generating unit(s); was illustrated. This system model has been simulated. All simulation results will be demonstrated and discussed.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115766520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ELMA.2019.8771634
G. Todorov, Dimitar Jetchev
The variable geometric dimensions of the magnetic circuit in the conical rotor induction motors in axial direction makes the magnetic flux non-uniform distribution in the length of the magnetic core. An analytical multisectional method for electromagnetic calculation has been developed accounting the special features of the motor design. It allows obtaining correct values of the magnetic flux density distribution and preventing oversaturation in some parts of the motor core. Numerical results for the non-uniform distribution of the magnetic flux density in the air-gap, teeth zone and yokes in longitudinal direction have been presented for two analyzed motors.
{"title":"Analysis of non-uniform magnetic flux distribution in conical rotor double-speed induction motors","authors":"G. Todorov, Dimitar Jetchev","doi":"10.1109/ELMA.2019.8771634","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771634","url":null,"abstract":"The variable geometric dimensions of the magnetic circuit in the conical rotor induction motors in axial direction makes the magnetic flux non-uniform distribution in the length of the magnetic core. An analytical multisectional method for electromagnetic calculation has been developed accounting the special features of the motor design. It allows obtaining correct values of the magnetic flux density distribution and preventing oversaturation in some parts of the motor core. Numerical results for the non-uniform distribution of the magnetic flux density in the air-gap, teeth zone and yokes in longitudinal direction have been presented for two analyzed motors.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127113958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ELMA.2019.8771682
D. Izvorska
Contemporary engineering education is based on the integrating role of individual expert which is why the present day fundamental goal of higher professional education is to achieve a rounded personality development and ensure continual enhancement of their professional competence (PC). The paper presents a theoretically formulated model for development and growth of PC in students of technical universities that is consistent with the goals and tasks of the process under research. It also presents a description of the model’s components which are organized in five separate blocks: purpose, functional, contents, organizational, and diagnostic-assessment. The paper recommends examples for interdisciplinary integration for different subjects (between subjects from humanitarian sciences and technical sciences, interdisciplinary laboratory exercises by using ICT, seminary exercises in the subjects "Physics", "Mathematics" and special learning disciplines etc.)
{"title":"A Model for Development of Professional Competence in Students of Technical Institutes of Higher Learning","authors":"D. Izvorska","doi":"10.1109/ELMA.2019.8771682","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771682","url":null,"abstract":"Contemporary engineering education is based on the integrating role of individual expert which is why the present day fundamental goal of higher professional education is to achieve a rounded personality development and ensure continual enhancement of their professional competence (PC). The paper presents a theoretically formulated model for development and growth of PC in students of technical universities that is consistent with the goals and tasks of the process under research. It also presents a description of the model’s components which are organized in five separate blocks: purpose, functional, contents, organizational, and diagnostic-assessment. The paper recommends examples for interdisciplinary integration for different subjects (between subjects from humanitarian sciences and technical sciences, interdisciplinary laboratory exercises by using ICT, seminary exercises in the subjects \"Physics\", \"Mathematics\" and special learning disciplines etc.)","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123552393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-06-01DOI: 10.1109/ELMA.2019.8771539
M. Iliev, B. Bedzhev, Monika Bedzheva, Kaloyan Kanchev
The binary phase manipulated radio signals, which auto – correlation functions have small side-lobes, are named perfect, as they have a critical role for many types of radio communication systems. With regard to this situation, in the paper we suggest several necessary conditions for existence of periodic binary nearly perfect PM signals with lengths N=1mod4. On their base an exhaustive computer search has been conducted. As a result, several unknown up to now periodic binary nearly perfect signals with lengths N≡1mod4 have been found.
{"title":"A Survey of Periodic Binary Nearly Perfect Signals with Lengths N≡1mod4","authors":"M. Iliev, B. Bedzhev, Monika Bedzheva, Kaloyan Kanchev","doi":"10.1109/ELMA.2019.8771539","DOIUrl":"https://doi.org/10.1109/ELMA.2019.8771539","url":null,"abstract":"The binary phase manipulated radio signals, which auto – correlation functions have small side-lobes, are named perfect, as they have a critical role for many types of radio communication systems. With regard to this situation, in the paper we suggest several necessary conditions for existence of periodic binary nearly perfect PM signals with lengths N=1mod4. On their base an exhaustive computer search has been conducted. As a result, several unknown up to now periodic binary nearly perfect signals with lengths N≡1mod4 have been found.","PeriodicalId":304248,"journal":{"name":"2019 16th Conference on Electrical Machines, Drives and Power Systems (ELMA)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125577371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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