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Eng. Proc., 2025, TechSys 2025

The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems

Plovdiv, Bulgaria | 15–17 May 2025

Volume Editors:
Nikola G. Shakev, Technical University of Sofia, Bulgaria
Valyo N. Nikolov, Technical University of Sofia, Bulgaria
Nikolay R. Kakanakov, Technical University of Sofia, Bulgaria
Sevil A. Ahmed-Shieva, Technical University of Sofia, Bulgaria

Number of Papers: 22
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Cover Story (view full-size image): The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems is organised by the Technical University of Sofia, Plovdiv Branch, within the framework of [...] Read more.
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6 pages, 2316 KiB  
Proceeding Paper
Simulation of Gravity Filling in a Silica Sand Mold with Gray Cast Iron (EN-GJL-250)
by Krum Petrov, Antonio Nikolov and Anton Mihaylov
Eng. Proc. 2025, 100(1), 1; https://doi.org/10.3390/engproc2025100001 - 25 Jun 2025
Viewed by 182
Abstract
This study presents a simulation modeling of the gravity filling of a sand casting mold with gray cast iron EN-GJL-250. An analysis of the fluid flow, the nature of the filling of the casting mold, and the possibility of forming defects, such as [...] Read more.
This study presents a simulation modeling of the gravity filling of a sand casting mold with gray cast iron EN-GJL-250. An analysis of the fluid flow, the nature of the filling of the casting mold, and the possibility of forming defects, such as voids and porosity due to metal shrinkage during the crystallization process, was performed. The simulation was performed using specialized software for simulating metal casting processes. The software allows the modeling of fluid dynamics and thermal conditions during the filling of the casting mold. The results obtained show the influence of the design of the sprue system, pouring temperature, and casting geometry on the movement of the fluid flow and the crystallization of the metal. The simulation also allows the visualization of turbulence and temperature gradients, helping to localize areas prone to defects. The results of this study could improve the quality of the specific casting and aid in selecting appropriate technology for the casting of a small series of high-quality castings. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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12 pages, 938 KiB  
Proceeding Paper
Energy Management of Charging Stations for Electric Vehicles
by Todor Stoilov, Krasimira Stoilova and Denis Chikurtev
Eng. Proc. 2025, 100(1), 2; https://doi.org/10.3390/engproc2025100002 - 26 Jun 2025
Viewed by 98
Abstract
The energy distribution between several charging stations for electric vehicles (EVs) is considered. An optimization problem is defined that aims to minimize the service time for EV charging. The charging sequence is evaluated and determined in view of the energy capacity constraint that [...] Read more.
The energy distribution between several charging stations for electric vehicles (EVs) is considered. An optimization problem is defined that aims to minimize the service time for EV charging. The charging sequence is evaluated and determined in view of the energy capacity constraint that is allocated to the set of stations. Empirical simulations and comparisons are performed to prove the “shorter EV charging capacity first” charging policy. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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11 pages, 1502 KiB  
Proceeding Paper
A Methodology for Modernization of Hydropower Unit in Pumped Hydro Energy Storage Systems
by Georgi Todorov, Konstantin Kamberov and Tsvetan Tsalov
Eng. Proc. 2025, 100(1), 3; https://doi.org/10.3390/engproc2025100003 - 26 Jun 2025
Viewed by 158
Abstract
This study aims to preview the possibilities for the modernization of pumped hydro energy storage systems, using actual engineering tools. The survey starts with a detailed analysis of the existing approaches and practices. Furthermore, a detailed methodology is developed and commented on in [...] Read more.
This study aims to preview the possibilities for the modernization of pumped hydro energy storage systems, using actual engineering tools. The survey starts with a detailed analysis of the existing approaches and practices. Furthermore, a detailed methodology is developed and commented on in detail. The major aim of this methodology is to evaluate both the technical and economic aspects of the modernization and to obtain maximal output of the system. The methodology involves the assessment of the current state of the art of the examined structures, using virtual prototyping techniques that are later combined with reliability prediction and failure modes and effects analysis, to be used together with a financial analysis of possible solutions. A primer of experienced damage in existing infrastructure further demonstrates the developed methodology. Its examination shows possible rehabilitation methods that are commented on and targeted for future detailed evaluation. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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7 pages, 581 KiB  
Proceeding Paper
Non-Linear Investigation of a Functionally Graded Pipe
by Victor Rizov
Eng. Proc. 2025, 100(1), 4; https://doi.org/10.3390/engproc2025100004 - 30 Jun 2025
Viewed by 38
Abstract
A pipe subjected to an evenly distributed internal pressure is investigated in this theoretical paper. The pipe has a thin wall that is built-up by a functionally graded engineering material. The circumferential stresses and strains in the pipe wall are investigated. In essence, [...] Read more.
A pipe subjected to an evenly distributed internal pressure is investigated in this theoretical paper. The pipe has a thin wall that is built-up by a functionally graded engineering material. The circumferential stresses and strains in the pipe wall are investigated. In essence, the current investigation is non-linear since the wall behaves as a non-linear elastic body with non-linearly distributed properties through the wall thickness. The different stages of the work of the wall are investigated and the corresponding parameters of stressed and strained state are derived. The dependence of the pressure on the material and geometrical parameters are studied. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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6 pages, 229 KiB  
Proceeding Paper
Reliability of Electro-Power Equipment Determined by Data in Its Operation and Storage
by Nikolay Gueorguiev, Atanas Nachev, Yavor Boychev, Konstantin Nesterov and Svetlana Yaneva
Eng. Proc. 2025, 100(1), 5; https://doi.org/10.3390/engproc2025100005 - 1 Jul 2025
Viewed by 9
Abstract
The reliability of the electro-power equipment of electrical power transmission systems is essential in ensuring an uninterrupted power supply with the necessary voltage and frequency stability. This is especially important when performing lengthy procedures requiring the serviceability of the electrical equipment used, such [...] Read more.
The reliability of the electro-power equipment of electrical power transmission systems is essential in ensuring an uninterrupted power supply with the necessary voltage and frequency stability. This is especially important when performing lengthy procedures requiring the serviceability of the electrical equipment used, such as those related to foundries and metallurgical processes, or with the processes of testing complex means for the remote control of electromagnetic radiation within the implementation of the Sustainable development of the Competence Center “Quantum Communication, Intelligent Security Systems and Risk Management” (QUASAR) Project, funded with the participation of the EU under the “Research, Innovation and Digitalization for Smart Transformation” Program 2021.2027 according to procedure BG16RFPR002-1.014. One of the main issues in this case is related to the availability of information regarding the technical condition of the deployed or reserve energy resources. In this connection, this study proposes methods for determining the quantity of operational equipment that is either in use or in storage, based on the reliability testing of a representative sample of it. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
19 pages, 946 KiB  
Proceeding Paper
Tariff Responses: A Graph-Theoretic Approach with Industry Dependencies
by George Pashev and Silvia Gaftandzhieva
Eng. Proc. 2025, 100(1), 6; https://doi.org/10.3390/engproc2025100006 - 1 Jul 2025
Viewed by 33
Abstract
In response to the growing prevalence of tariffs as instruments of economic policy and strategic competition, this paper introduces a formal mathematical framework for optimizing counter-tariff strategies. We model the global trade ecosystem as a multi-layered, directed, weighted hypergraph, where vertices represent countries, [...] Read more.
In response to the growing prevalence of tariffs as instruments of economic policy and strategic competition, this paper introduces a formal mathematical framework for optimizing counter-tariff strategies. We model the global trade ecosystem as a multi-layered, directed, weighted hypergraph, where vertices represent countries, industries, and subindustries, and hyperedges capture complex trade relationships and supply chain dependencies. The proposed framework employs bilevel optimization techniques to maximize strategic impact on target economies while minimizing self-inflicted economic costs. Through integration of graph theory, spectral analysis, and multilevel optimization methods, we develop a rigorous formalism that enables policymakers to identify optimal counter-tariff portfolios under various constraints. Our model explicitly accounts for industrial interdependencies, where export competitiveness depends on imported inputs, thus providing a more realistic representation of global value chains. Case studies applying our model to historical trade disputes demonstrate its capacity to generate superior strategic outcomes compared to conventional approaches. The framework’s axiomatic foundation allows for rapid recalibration in response to shifting economic conditions and policy objectives. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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6 pages, 460 KiB  
Proceeding Paper
Non-Linear Creep of Spherical Container with Fluid Under Increasing Pressure
by Victor Rizov
Eng. Proc. 2025, 100(1), 7; https://doi.org/10.3390/engproc2025100007 - 1 Jul 2025
Viewed by 5
Abstract
This paper presents an analysis of the time-dependent response of a spherical container to internal pressure that increases over time. The wall of the container is relatively thin, in the sense that the wall thickness is negligible in comparison to the container’s radius. [...] Read more.
This paper presents an analysis of the time-dependent response of a spherical container to internal pressure that increases over time. The wall of the container is relatively thin, in the sense that the wall thickness is negligible in comparison to the container’s radius. The wall is composed of three layers. The two surface layers of the wall are identical, i.e., they are made from the same material and have the same thickness. One of the most important features regarding the response of the wall layers is the non-linear creep. The stresses and strains are determined, and their relationships with the parameters of the layers are studied. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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9 pages, 1742 KiB  
Proceeding Paper
Investigation of the Efficiency of a Peltier Element
by Atanas Radulov, Mario Dechev and Misho Matsankov
Eng. Proc. 2025, 100(1), 8; https://doi.org/10.3390/engproc2025100008 - 1 Jul 2025
Viewed by 10
Abstract
This paper presents the implementation of a modern approach for automatic measurement, data acquisition, and processing using custom-developed software based on the ARDUINO version: 2.3.6 platform. State-of-the-art sensing elements are employed for enhanced precision and reliability. The obtained results are graphically visualized for [...] Read more.
This paper presents the implementation of a modern approach for automatic measurement, data acquisition, and processing using custom-developed software based on the ARDUINO version: 2.3.6 platform. State-of-the-art sensing elements are employed for enhanced precision and reliability. The obtained results are graphically visualized for comprehensive analysis. The ARDUINO microcontroller and its associated open-source programming environment are primarily designed for general-purpose users rather than specialized industrial applications. The study focuses on the experimental investigation of the characteristics of a Peltier element. The interdependence between current, voltage, internal resistance, and temperature differential is examined in detail. The findings concerning efficiency analysis are intended to support students across various engineering disciplines during their educational process. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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9 pages, 2824 KiB  
Proceeding Paper
Approaches to Creating Colorful 3D-Printed Parts and Reliefs
by Mihail Zagorski, Radoslav Miltchev, Boyan Dochev and Nikolay Stoimenov
Eng. Proc. 2025, 100(1), 9; https://doi.org/10.3390/engproc2025100009 - 2 Jul 2025
Viewed by 32
Abstract
The present article aims to examine different approaches and technologies for producing multi-color 3D printed parts and reliefs using FDM/FFF printing technology. Several examples of parts used in the fields of technology, architecture, marketing and art are presented. The innovative HueForge software version [...] Read more.
The present article aims to examine different approaches and technologies for producing multi-color 3D printed parts and reliefs using FDM/FFF printing technology. Several examples of parts used in the fields of technology, architecture, marketing and art are presented. The innovative HueForge software version 0.8.1 is used to create a multi-color relief. The process of establishing the Transmission Distance parameter of a given filament, which is key to creating colored reliefs with HueForge, is also examined. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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16 pages, 7834 KiB  
Proceeding Paper
Exploring the Connection Between Design and Materials Through the Digitalization of Modular Solutions
by Mihaela Gadzheva-Nedelcheva and Ivelina Daulova
Eng. Proc. 2025, 100(1), 10; https://doi.org/10.3390/engproc2025100010 - 3 Jul 2025
Viewed by 5
Abstract
This research presents a methodically consistent creative act related to the digitization of planar pictorial images. After the transformation based on the modular grids, completely new images are created—different from their original source. The successful solutions found in this way are applicable to [...] Read more.
This research presents a methodically consistent creative act related to the digitization of planar pictorial images. After the transformation based on the modular grids, completely new images are created—different from their original source. The successful solutions found in this way are applicable to various areas of graphic and product design. Multiple experiments were conducted in a digital environment on the same image applied to different material carriers in relation to the function of the product—different types of textiles and paper. To more accurately describe the experiments, three-dimensional realistic shapes from different materials have been created, onto which the modular designs have been applied. The report provides a methodical modular principle of thinking and action, justified by the applied results of the set experiment. The experiment was conducted and directly implemented under a scientific research project for an R&DS (The Research and Development Sector) project (Agrmt. 241XTД0006-06) at the Technical University, Sofia. The study involved three students from the Engineering Design Department, as well as the authors of this article—all supporters of the creative principle. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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8 pages, 1970 KiB  
Proceeding Paper
Optimization of Accuracy and Repeatability in Laser Micro-Processing Using Experimental Design
by Todor Gavrilov, Todor T. Todorov, Yavor Sofronov, Hristiana Nikolova and Angel Todorov
Eng. Proc. 2025, 100(1), 11; https://doi.org/10.3390/engproc2025100011 - 2 Jul 2025
Viewed by 11
Abstract
This study focuses on optimizing the laser micromachining process to achieve precise geometric features. The main objective is to develop a systematic approach for analyzing the process parameters that influence the repeatability of laser material removal for edge-rounding of 50 and 75 μm [...] Read more.
This study focuses on optimizing the laser micromachining process to achieve precise geometric features. The main objective is to develop a systematic approach for analyzing the process parameters that influence the repeatability of laser material removal for edge-rounding of 50 and 75 μm in radius. The research employs the Taguchi method for the experimental design, allowing the identification of optimal process parameters that ensure high consistency. Repeatability is assessed through the evaluation of eight consecutive layers in depth, where the laser removes material, and the average depth is calculated by dividing the total removed depth by eight. This statistical approach allows for a comprehensive analysis of process stability. A key aspect of this study is the development of a predictive model based on experimental data, allowing a selection of the most influential parameters to achieve the desired outcome. By implementing a structured optimization process, this research aims to enhance process efficiency, minimize deviations, and improve the overall quality of laser micromachining. These findings contribute to the advancement of precision manufacturing techniques by providing a reliable methodology for process control and repeatability enhancement. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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8 pages, 830 KiB  
Proceeding Paper
Process Optimization with Smart BLE Beacons
by Stanimir Kabaivanov and Veneta Markovska
Eng. Proc. 2025, 100(1), 12; https://doi.org/10.3390/engproc2025100012 - 3 Jul 2025
Viewed by 42
Abstract
The optimization of workflows and processes based on available data and observations is very important for gaining efficiency, but is often limited by the amount of available information and the time required to collect it. In this paper we suggest a flexible solution, [...] Read more.
The optimization of workflows and processes based on available data and observations is very important for gaining efficiency, but is often limited by the amount of available information and the time required to collect it. In this paper we suggest a flexible solution, based on wearable radio beacons and software analysis of their inputs. A prototype of the system was built with NRF52832 smart tags and the Raspberry Pi 4 gateway and data analysis system. Experiments carried out on the first samples indicate that it is indeed possible to seamlessly collect and process information that is then used to optimize various actions, ranging from production to administrative tasks. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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14 pages, 1805 KiB  
Proceeding Paper
Helicopter Rotor Aerodynamic Characteristics in Ground Effect: Numerical Study
by Gabriel Georgiev
Eng. Proc. 2025, 100(1), 13; https://doi.org/10.3390/engproc2025100013 - 4 Jul 2025
Viewed by 24
Abstract
This article represents a full estimation of helicopter rotor aerodynamic characteristics in ground effect conditions through the application of a coupled empirical blade element–momentum theory algorithm. The main focus of this research includes the evaluation of the required weighted power coefficients [...] Read more.
This article represents a full estimation of helicopter rotor aerodynamic characteristics in ground effect conditions through the application of a coupled empirical blade element–momentum theory algorithm. The main focus of this research includes the evaluation of the required weighted power coefficients CPσ for a hovering state in close proximity to obstacles and their relation to the weighted thrust force coefficients’ values CTσ, varying the relative distance from the helicopter rotational plane to the ground surface HR and the rotor’s collective pitch angle (θ). The represented numerical and experimental results show that an increase in the collective pitch angles (θ) leads to a rise in the generated weighted thrust force coefficients CTσ and in the weighted power coefficients CPσ for every individual fixed normalized distance from the ground surface HR. Moreover, a decline in the relative distance from the ground HR requires less power to keep the rotation going in hover. The dependencies indicate that the ground effect zone covers a distance of up to 2R from the rotational plane to the ground surface. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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8 pages, 1954 KiB  
Proceeding Paper
Ensuring Accuracy in Turning
by Svetlana Koleva
Eng. Proc. 2025, 100(1), 14; https://doi.org/10.3390/engproc2025100014 - 4 Jul 2025
Viewed by 9
Abstract
At the stage of the final processing of surfaces, the quality indicators of the surfaces of parts—size, shape in cross-section and longitudinal section, mutual arrangement of surfaces, and roughness—are obtained. This includes technical and organizational measures and activities that are laid down or [...] Read more.
At the stage of the final processing of surfaces, the quality indicators of the surfaces of parts—size, shape in cross-section and longitudinal section, mutual arrangement of surfaces, and roughness—are obtained. This includes technical and organizational measures and activities that are laid down or taken into account in the applied technology. This publication constructs cause-and-effect diagrams of the factors influencing the achievement of each of these accuracy indicators. Ways to reduce the negative impact of some factors are indicated. Errors related to the components of the technological system are analyzed and grouped. Tasks related to accurate process design are defined. Guidelines related to structural accuracy design are given. The technological conditions for ensuring the accuracy of finishing operations when processing parts by turning are formulated. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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10 pages, 2832 KiB  
Proceeding Paper
Gaining Python Skills Through Interactive Education Robot Ozobot EVO
by Maya Staikova
Eng. Proc. 2025, 100(1), 15; https://doi.org/10.3390/engproc2025100015 - 4 Jul 2025
Viewed by 9
Abstract
This paper explores the potential of the Ozobot EVO mobile robot as an educational tool for teaching Python programming. While the robot is currently designed for younger students through color and block programming, it is not yet widely utilized for teaching text-based coding. [...] Read more.
This paper explores the potential of the Ozobot EVO mobile robot as an educational tool for teaching Python programming. While the robot is currently designed for younger students through color and block programming, it is not yet widely utilized for teaching text-based coding. The Ozobot’s compatibility with Python presents a valuable opportunity for students to visualize their programming concepts through the robot’s actions, offering a more engaging alternative to console-based learning. The increasing use of the Raspberry Pi, a single-board computer programmed in Python, has necessitated the inclusion of Python in the curriculum. However, students often find learning Python challenging and demotivating. To enhance STEM education and student motivation, this paper proposes sample Python code for the Ozobot EVO, aiming to encourage educators to integrate the robot into their teaching. I suggest some Python code examples for the Ozobot EVO. This is to help educators see how they can use the robot in their lessons. Specifically, code examples for controlling motion, sound, light, and combinations of these functionalities are presented. When students see the robot react immediately to their code, they can understand programming ideas much better than just seeing text in the Python console. The Ozobot EVO mobile robot offers a solid foundation for learning Python programming. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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13 pages, 5812 KiB  
Proceeding Paper
Development of an Educational Omnidirectional Mobile Manipulator with Mecanum Wheels
by Nayden Chivarov, Radoslav Vasilev, Maya Staikova and Stefan Chivarov
Eng. Proc. 2025, 100(1), 16; https://doi.org/10.3390/engproc2025100016 - 4 Jul 2025
Viewed by 10
Abstract
The developed omnidirectional mobile manipulator is an educational omnidirectional mobile manipulator that utilizes the Raspberry Pi Pico W and is programmed in Python. It is designed to enhance STEM education by providing an interactive environment for studying robotics, sensor integration, and programming techniques. [...] Read more.
The developed omnidirectional mobile manipulator is an educational omnidirectional mobile manipulator that utilizes the Raspberry Pi Pico W and is programmed in Python. It is designed to enhance STEM education by providing an interactive environment for studying robotics, sensor integration, and programming techniques. The robot is built on an off-the-shelf chassis equipped with Mecanum wheels and a robotic arm actuated by servo motors. As part of this project, the control electronics were designed and implemented to enable seamless operation. While the platform allows students to program the robot as part of the STEM curriculum, our base software solution, developed in Python, provides control of both the mobile base and the robotic arm via a web interface accessible through the robot’s Wi-Fi hotspot. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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6 pages, 521 KiB  
Proceeding Paper
LoRaWAN IoT System for Measuring Air Parameters in a Traffic Monitoring Station
by Stefan Lishev, Grisha Spasov and Galidiya Petrova
Eng. Proc. 2025, 100(1), 17; https://doi.org/10.3390/engproc2025100017 - 7 Jul 2025
Viewed by 18
Abstract
Traffic measurement systems are an essential part of intelligent transportation systems (ITS). These are specialized transport infrastructures where traffic data is collected and analyzed in order to optimize the use of road systems, improve transport safety, and implement future transport plans. The rapid [...] Read more.
Traffic measurement systems are an essential part of intelligent transportation systems (ITS). These are specialized transport infrastructures where traffic data is collected and analyzed in order to optimize the use of road systems, improve transport safety, and implement future transport plans. The rapid development of transportation systems, urbanization, and industrialization have led to a global problem of air pollution. This has raised the topical issue of measuring and monitoring environmental parameters at traffic monitoring stations in ITS. In this paper, we present a wireless environmental monitoring system, which is a subsystem of a traffic monitoring station. Along with measuring traffic parameters, the station also collects useful meteorological information. A novel hybrid, dual-band IoT system based on LoRa and LoRaWAN for environmental parameters monitoring is presented. The hardware realization of a developed hybrid LoRaWAN end device, together with the sensors used for the measurement of air parameters, is described. Initial results from real test monitoring of environmental parameters on the road in urban environments are presented as a proof of concept. The presented wireless environmental monitoring system can also be used for indoor or outdoor air pollution monitoring, serving as a useful complement to intelligent transport systems. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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7 pages, 532 KiB  
Proceeding Paper
FPGA Prototyping of Heterogeneous Security Architecture for Educational Purposes
by Stefan Stoyanov, Nikolay Kakanakov and Maria Marinova
Eng. Proc. 2025, 100(1), 18; https://doi.org/10.3390/engproc2025100018 - 7 Jul 2025
Viewed by 24
Abstract
Modern day hardware design is heavily focused on software simulations and verification. ASIC design is complex, and its abstraction may lead to losing motivation to develop knowledge and skills in the field. It is also very costly and inaccessible outside the industry, especially [...] Read more.
Modern day hardware design is heavily focused on software simulations and verification. ASIC design is complex, and its abstraction may lead to losing motivation to develop knowledge and skills in the field. It is also very costly and inaccessible outside the industry, especially on a larger scale. FPGAs are devices which are affordable and allow unexperienced people, like students, to have an accessible and observable starting point in hardware development. On the other hand, protocol standards and devices nowadays are so complex that one will need to spend years to understand and feel comfortable dealing with corporate methodologies, environments and development process. One of the still evolving, recently developed ISA for example, RISC-V, is a broad area to learn. Often the fastest and in-depth way to learn is by observation, getting familiar with accessible yet challenging design and making modifications to and experimenting with such platforms. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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10 pages, 3944 KiB  
Proceeding Paper
Modelling and Optimization of the Precision Hot Forging/Extrusion Process of an Asymmetric C45E/1.1191 Carbon Steel Bearing Element
by Antonio Nikolov, Anton Mihaylov and Dimiter Yankov
Eng. Proc. 2025, 100(1), 22; https://doi.org/10.3390/engproc2025100022 - 8 Jul 2025
Abstract
Precision extrusion forging is an innovative manufacturing process for trouble-free production of high-quality components with an accurate shape. The process provides a reduced technological chain and high production efficiency, as only certain surfaces need additional processing. This study used QForm software as an [...] Read more.
Precision extrusion forging is an innovative manufacturing process for trouble-free production of high-quality components with an accurate shape. The process provides a reduced technological chain and high production efficiency, as only certain surfaces need additional processing. This study used QForm software as an environment for simulating precision extrusion forging. The main goal of this research was to present a brief overview of the latest research on the simulation of precision extrusion forging, with an emphasis on the production cycle rather than on mathematical description. This article examines the processes of simulation modeling of precision extrusion forging with newly designed tooling for the manufacture of a newly introduced asymmetric load-bearing facade element patented by Braykov. With the help of simulation modeling, appropriate modes for specific production were established, and were later implemented. The production process itself is briefly presented at the end of this article. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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880 KiB  
Proceeding Paper
An Algorithm for Assessment of Time Series Data Related to the Materials Used for Packaging in the Market
by Delyana Dimova
Eng. Proc. 2025, 100(1), 23; https://doi.org/10.3390/engproc2025100023 (registering DOI) - 8 Jul 2025
Abstract
This article presents an algorithm for the assessment of time series data related to the materials used for packaging in the market in Bulgaria for the period 2010–2023. The considered elements include the quantities of the following types of materials: paper/cardboard, plastic, wood, [...] Read more.
This article presents an algorithm for the assessment of time series data related to the materials used for packaging in the market in Bulgaria for the period 2010–2023. The considered elements include the quantities of the following types of materials: paper/cardboard, plastic, wood, metal, glass, and others. They are extracted from the built relational database and subsequently processed and summarized. In this regard, relevant criteria (rules) are formed and applied and certain variables are calculated. In addition, analysis of variance (Anova) and Tukey’s test are also used for these data. The results show that one of the materials (paper/cardboard) in 2010–2018 has relatively higher quantities compared to the rest materials. A similar situation occurs for the element plastic, in 2019–2023. The calculated relative shares of the respective quantities of packaging materials show that more than half of them in the market are made of paper/cardboard and plastic. Some dynamic changes are observed in the quantities for the materials metal and wood. The indicator values for the other materials are significantly lower than the rest. The developed algorithm can be applied to study other time series data in fields such as ecology, finance, etc. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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8 pages, 1683 KiB  
Proceeding Paper
Investigation of Technological System Stability During Side Milling
by Iliya Chetrokov, Sabi Sabev and Plamen Kasabov
Eng. Proc. 2025, 100(1), 24; https://doi.org/10.3390/engproc2025100024 (registering DOI) - 9 Jul 2025
Abstract
This study analyzes technological system stability during side milling by evaluating the influence of two critical parameters: the radial depth of cut (Ae) and feed per tooth (fz). The experiment was conducted on prismatic samples with stepped geometries to [...] Read more.
This study analyzes technological system stability during side milling by evaluating the influence of two critical parameters: the radial depth of cut (Ae) and feed per tooth (fz). The experiment was conducted on prismatic samples with stepped geometries to measure deformation at various levels of Ae and f. Regression analysis showed a significant influence of both factors on deformation, with Ae having a stronger effect. The model explains a high level of the variance, confirming the reliability of the experimental data. The results provide guidance for optimizing parameters to improve stability and reduce dimensional deviations. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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10 pages, 1971 KiB  
Proceeding Paper
An Experimental Evaluation of Latency-Aware Scheduling for Distributed Kubernetes Clusters
by Radoslav Furnadzhiev
Eng. Proc. 2025, 100(1), 25; https://doi.org/10.3390/engproc2025100025 (registering DOI) - 9 Jul 2025
Abstract
Kubernetes clusters are deployed across data centers for geo-redundancy and low-latency access, resulting in new challenges in scheduling workloads optimally. This paper presents a practical evaluation of network-aware scheduling in a distributed Kubernetes cluster that spans multiple network zones. A custom scheduling plugin [...] Read more.
Kubernetes clusters are deployed across data centers for geo-redundancy and low-latency access, resulting in new challenges in scheduling workloads optimally. This paper presents a practical evaluation of network-aware scheduling in a distributed Kubernetes cluster that spans multiple network zones. A custom scheduling plugin is implemented within the scheduling framework to incorporate real-time network telemetry (inter-node ping latency) into pod placement decisions. The assessment methodology combines a custom scheduler plugin, realistic network latency measurements, and representative distributed benchmarks to assess the impact of scheduling on traffic patterns. The results provide strong empirical confirmation of the findings previously established through simulation, offering a validated path forward to integrate not only network metrics, but also other performance-critical metrics such as energy efficiency, hardware utilization, and fault tolerance. Full article
(This article belongs to the Proceedings of The 14th International Scientific Conference TechSys 2025—Engineering, Technologies and Systems)
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