Lilyana S. Koleva

20230300-01
Evaluation of the integration of systems for quality management in the field of higher education
Pavlina Shopova, Maria Todorova, Lilyana S. Koleva, Elena G. Koleva

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For the purposes of continuous improvement of the quality management system in any organization, and in particular those in the field of higher education, an assessment of the degree of integration (maturity) of the system ...  read more

20230200-02
Classification of chest X-Ray images using Orange Data Mining Tool
Lilyana S. Koleva, Georgi A. Filipov

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In this article, the capabilities of the Orange Data Mining software product to classify chest Xray images are shown. Viewed images of patients are divided into three categories: healthy, with Covid-19 and with viral pneumonia. ...  read more

20230100-02
Development and implementation of a national conference relational database in MS Access
Ventsislava V. Dimitrova, Lilyana S. Koleva

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Holding a national conference involves processing of a large amount of documents and information related to the smooth running of the event. In this paper, the development of a relational database in the MS Access environment ...  read more

20220508-03
Optimization of electron beam welding of Ti-6Al-4V thin plates
Lilyana S. Koleva, Asya Lozeva, Elena G. Koleva

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In this paper the electron beam welding of Ti–6Al–4V thin plates is simulated by implementation of a moving linear heat source model. The simulation results are used for estimation of regression models for the dependencies ...  read more

20220508-04
Simulation of electron beam welding of Inconel 718 thin plates
Lilyana S. Koleva, Natalia Hristova, Elena G. Koleva

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In this paper the simulation of electron beam welding of Inconel 718 thin plates by a moving linear heat source is considered. Regression models for the molten pool geometry characteristics, depending on the electron beam ...  read more

20220508-05
Robust model-based multicriterial optimization strategies for electron beam welding of Steel 45
Elena G. Koleva, Lilyana S. Koleva

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In this paper an experimental study of the geometrical characteristics of the cross-sections of the thermally affected areas obtained by electron beam welding joints of carbon steel grade 45 is made. The thermally affected ...  read more

20210912-03
Graphical user interface for simulation of the mechanical properties of a new type of black locust plywood for construction
Lilyana S. Koleva, Asen N. Hristov

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The mechanical properties bending strength and modulus of elasticity in bending of a new type plywood for construction, based on black locust wood, have been investigated in relationship with the bonding technological factors. ...  read more

20210912-02
Process parameter optimization of electron beam melting and refining of titanium
Elena G. Koleva, Lilyana S. Koleva, Volodia V. Dzharov, Boriana S. Spasova

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The mechanical properties bending strength and modulus of elasticity in bending of a new type plywood for construction, based on black locust wood, have been investigated in relationship with the bonding technological factors. ...  read more