Abstract: In the industry, the continuous operation of machines is required, making it difficult to stop and carry out preventive maintenance to check the status of the wear elements. However, the early detection of a faulty element allows avoiding further damage to the machine and the user. Thus, it is very important to have continuous and remote monitoring of the machine’s status and the wear of its elements without stopping the process; to this aim, vibration analysis is one of the most effective techniques. In this paper, a vibration-based fault detection system with IoT capabilities applied to a vibrating conveyor is presented. The system processes the acceleration force measured in 6 points of the machine using two-axis wireless accelerometers and obtains the position-time date time to derive three machine parameters: stroke, direction and frequency; comparing these values to their nominal reference the system provides a visual interface to inform the operator both, in situ and remotely, the status of the machine. The system performance is validated through a physical conveyor prototype.

Keywords: Vibration analysis; Conveyor machine; Fault detection system; IoT

Abstract: JUICE - JUpiter ICy moons Explorer - is the first large-class mission of ESA (European Space Agency). Planned for launch in Sept 2022 and arrival at Jupiter in 2029, it will spend at least three years making detailed observations of the giant gaseous planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. Space technical team developed power supply unit for PEP (Particle Enviroment Package) instrument. PEP and its sensors will examine the plasma environment in the Jovian system. PEP will measure density and fluxes of positive and negative ions, electrons, exospheric neutral gas, thermal plasma and energetic neutral atoms. The nominal onboard voltage is 28 V on the space probe. Space technical team had a job to develop power supply unit DCC (Direct Current Converter) for the sensors of PEP. The job was a great challenge because of the required high reliability and that reliable operation had to be ensured in extreme circumstances. We present in this article the realization of DCC. The DCC required for its tests to develop a special test equipment called EGSE (Electronic Ground Support Equipment). The EGSE was developed by the SGF Ltd. and supports checks of DCC. In this article we present the DCC, the quality insurance methods and the tests carried out by EGSE.

Keywords: JUICE; Icy moons; Jupiter; ESA; DCC; EGSE

Abstract: Aquaplaning at wet road conditions and high speeds can be a source of dangerous driving situations and accidents. The proper understanding of characteristic effects can be crucial in early aquaplaning detection and accident avoidance, essential for driver and driver assistance systems and trajectory planning for self-driving cars. Four test vehicles were equipped with a basic measurement system, and measurements were performed to evaluate characteristics of aquaplaning, such as wheel spin-up and wheel spin-down, change of rolling resistance, tyre slip slope, and tie rod force. Driveline configuration, type, wear and inflation pressure of the tyre(s), water level height next to chosen speed and performed manoeuvre significantly affect vehicle behaviour and thus the possibility to detect aquaplaning conditions. The results and main findings may allow and help establish corresponding methods to early detect aquaplaning and dangerous driving conditions.

Keywords: Aquaplaning; Hydroplaning; Vehicle Dynamics; Advanced Driver Assistance Systems, Active Safety Systems; Identification and Estimation

Abstract: In this study, the initial problem is the capacity of the human mind to set up a conceptual model. The novelty of this article is that we show that defined concepts created by the human mind can be passed on to an artificial intelligence-based expert system. The expert system helps the human mind to settle the logical connections between the defined terms and the conceptual model thus the created model will be better than what man could have set up without an expert system. The appearance and role of employee turnover has become a more and more important factor in the daily business of corporate life. Scientific journals have examined the positive and negative effects of it, which has also provided useful knowledge for practitioners. These articles have examined the impact of employee turnover in countless aspects, but one aspect was the same in all literature: the impact of turnover on a company is not negligible and cannot be ignored in terms of neither material nor moral aspects. As a starting point for our research, we systematically reviewed the literature on employee turnover and selected six concepts that are bilaterally related to our phenomenon. Based on the terms and the correlation of it, we created a conceptual model that was examined with the help of an artificial intelligence-based system. To select a system, we reviewed the classifications of the artificial intelligence-based systems which can model human decision making and can help our research. Relying on the processing of the literature review articles, we selected and briefly characterized a rule-based reasoning system, and investigated the rule constellations of it, which can model the turnover cases as the topic of our study. Based on our experience in observing, consulting, and working with decision-makers, we examined the aspects of employee turnover phenomenon in the analysis and we constructed a three-level model that found logical relationships between each subcategory and was able to realistically reflect certain behavioral patterns of the physical workforce of a manufacturing company. The analysis was performed using a rule-based system, which used logical rules and found classical “if-then” connections in the employee behavior cases. According to our examination, our outcomes can provide credible results for further research activities as well as for practitioners.

Keywords: manual worker; rule-based reasoning; employee turnover

Abstract: Demanding requirements on the circular economy, cost savings, the effectiveness of the power grids operation press the operators of large electrical machines and other equipment to search for new methods of equipment management, maintenance, and renewal. At present, the management of important electrical machines is mostly related to offline concepts. This paper brings a summary of the current management practices and represents an introduction of a modern approach - Condition Based Management as well. For the large high voltage, electric machines are here proposed method of using aging models as a part of online diagnostic systems to estimate machine state. An example of the modeled use of condition-based modeling and residual life of insulating material is here presented. This approach should be employed in the employment of new renewable energy resources as well.

Keywords: asset management; residual life; insulating system; aging model

Abstract: The unexpected challenges posed by the pandemic also have transformed university education. Information technology is still the most advantageous field, as IT tools in education are more widespread. We have been using the ProgCont system for automatic evaluation of programming tasks since 2011 at the Faculty of Informatics of the University of Debrecen. The system’s responsibilities have expanded over the years, and due to the pandemic, it will have to play a more significant role in self-preparation. Initially, we used the system to evaluate competitive tasks and later examinations. In this period, the feedback was limited to accepting or rejecting the submitted solutions. A submitted solution is accepted if the application produces the appropriate output for the problem’s input. Usually, we test the submissions with several inputs (test cases) for each problem. To provide additional information about the reason for rejection, we would like to supplement test cases with comments (annotations) that identify the test cases’ unique properties. Our goal is to help identify the subproblems that need improvement in case of a partially correct solution. In our article, we would like to present the potential of this development. We chose a problem that received an impressive number of solutions. We created new test cases for the problem with annotations, and by re-evaluating the submissions, we compared how much extra information students and instructors obtained using the annotations. The presented example proves that this new development direction is necessary for students’ self-preparation and increases differentiated education possibilities.

Keywords: ProgCont system; programming education; automatic solution evaluation; test case annotations

Abstract: The authors of the paper present the high-frequency synchronous voltage injections-based sensorless vector control method on an interior permanent magnet synchronous machine (IPMSM). For development and testing purposes a lumped-parameter, saturating machine model was created and will be presented, which also involves cogging torque effects. The presented machine model runs faster than the coupled simulations allowing to develop the control algorithms much faster. The machine model was obtained by combining the finite element method (FEM) analysis’s results with the space vector-based equations. The sensorless algorithm will be detailed, followed by the proposed estimator structure. The authors present a new dynamic model for the PLL-based synchronous injection estimator, making possible to tune its PI controller. Parameter sensitivity and stability analysis will be presented, based on the proposed estimator structure and FEM analysis results. Simulation result are presented, compared, and validated by experimental measurement results.

Keywords: Vector Control; Permanent Magnet Synchronous Machine; Sensorless Control; High-Frequency Signal Injection

Abstract: In the automotive industry, manufacturing companies are constantly improving and monitoring their processes with different Key Performance Indicators (KPIs) in order to achieve higher profits. One of the KPIs is the Overall Equipment Effectiveness (OEE), which represents the efficiency of the different machines and assembly lines. High OEE percentage means good performance and quality. Using Manufacturing Execution System (MES) data the OEE contributors such as availability, performance and quality are calculated and followed at the manufacturing area day by day. This paper concentrates on the entire OEE life cycle at the automotive semi-automatic assembly lines. Firstly, a literature review demonstrates scientific relevance. Secondly, the phases of OEE life cycle are revealed and presented regarding a passenger car seat structure production life cycle. Third section points at the connection between OEE percentage and maintenance, labour and quality costs at the assembly lines. In addition to the theoretical approach, real, practical data are also demonstrated based on experiences from the last fifteen years.

Keywords: KPI; OEE; MES; assembly line; life cycle; production cost

Abstract: Mobile robots are designed to perform different tasks in many different fields such as production, fast delivery, defence industry and space exploration. Advances in mobile robots are crucial as they can perform tasks that are difficult, dangerous or inefficient for humans. In this context, we discuss the improvement of velocity planning in the rapidly evolving field of autonomous mobile robots. In this study, we focus on mobile robots with high variance in their weight. Mobile robots can transport loads or autonomous personal transportation vehicles such as wheelchairs, which can be given as an example of these types of systems. This study focuses specifically on linear velocity planning for providing the same performance for all payloads on the mobile robot considering comfort and safety. For this aim, we propose a new velocity planning method based on fuzzy logic which has several advantages over previous methods. The suggested algorithm is tested in simulations using certain performance measurement metrics. After the observation of successful results, real-world experimental tests are performed to prove the real-time applicability of the proposed approach.

Keywords: autonomous robots; mobile robots; velocity planning; fuzzy logic

Abstract: Digital health has accelerated, in part, due to the recent COVID-19 pandemic in terms of both implementation and acceptability. However, while digitalization in healthcare brings an opportunity to improve the quality of care, this creates a need for sustainability through funding of these technologies by healthcare payers. Traditional innovations such as pharmaceuticals are rigorously evaluated by health technology assessment (HTA) bodies in many countries to advise payers on how scarce funds can be efficiently distributed. The aim of this study was to review the HTA evidence frameworks being applied by HTA bodies or payers for the evaluation of digital health interventions. We reviewed recent literature and the websites of the leading payer and HTA bodies to understand the frameworks which have been used for the evaluation of digital health innovations. We found that 6 frameworks directly addressed digital health technologies for the purposes of pricing and reimbursement. Building on previous work, we reviewed the context and evidence domains of each framework. The evidence requirements of the included frameworks were diverse, and their domains extended the European Network for Health Technology Assessment (EUnetHTA) Core HTA Model. Our research concluded that while some frameworks exist, they require additional refinement to ensure that the level of evidence is commensurate with the technology being assessed and that relevant stakeholders are included to more holistically assess the outcomes produced. Developers of digital health technologies need to be aware of the evidence requirements by payers or HTA bodies, which differ from HTA requirements for traditional health technologies and may represent additional hurdle before entering publicly financed healthcare markets.

Keywords: digital health; e-health; mHealth; telehealth; telemedicine; reimbursement; health technology assessment

Abstract: The key focus of this article is forecasting of residential power consumer load profiles using tuned Type-2 Fuzzy Inference System. The characteristics of residential load profiles have been investigated. In contrast to similar studies, non-averaged profiles with one minute resolution have been used. Additionally, the presence of various shapes in these profiles increases the difficulty of forecasting. In this paper, the process of creating, learning and tuning Type-2 Fuzzy Inference System with Particle Swarm Optimization and Genetic Algorithm is presented. The accuracy of the forecasts was evaluated using Root-Mean-Square Error calculations. The obtained results showed that the proposed method can predict detailed load profiles efficiently. The biggest forecast error was 0.1165, while the lowest was 0.0642. Additionally, the value of error was influenced also by the type of day (working day or Saturday). Moreover, the Particle Swarm Optimization proved to be a more precise tuning solution than the Genetic Algorithm, obtaining lower error values. Several aspects related to the residential load profiles forecasting are also discussed in this paper. The presented research may be useful for companies selling electricity.

Keywords: load profiles; residential power consumers; forecasting; fuzzy logic; type-2 fuzzy inference system

Abstract: This work summarizes the key findings of a research run in 2020 in the Hungarian Financial Sector regarding critical failure factors of process development by Lean Methodology. An online questionnaire asked the invited participants of banking, insurance, and counseling firms to rank the difficulties of typical activities in an operational improvement project. Besides, they had the opportunity to add the reasons for implementation issues. Twelve main problems were identified based on the results, including change management-, measurement, and resource availability-related ones. Since these issues are not independent of each other, cause-effect connections among them were defined too. Finally, seven groups of recommendations were articulated for handling the most frequent implementation difficulties. The originality of this work is that this is the first summary of critical failure factors of process-oriented Lean office transformation projects in the financial sector in the Central European Area. The identified factors can only be applied without additional interpretation only in similar projects in the similar industry.

Keywords: Lean Office; Process Development; Critical Failure Factor

Abstract: This work focuses on the pressure drop of the cooled fluid in the shell side of the heat pump’s evaporator since the structures and the results obtained for the process characteristics of the models available in the literature show a significant standard deviation. Hence, the mathematical modeling and description of the heat pump is rather uncertain due to the inaccuracy of the functions describing the pressure drop. This research paper presents a new formula developed on the basis of the measurements, which can be used to calculate the pressure drop in the shell side of the heat pump evaporator with greater accuracy compared to the correlations found in the literature. The maximum discrepancy - from measurement values - of the values yielded by the pressure drop model with the new proposed correlation as set up by the author is ɛmax=5.72%, while the average discrepancy is only ɛ=2.58%. The presented new correlation was determined under the measuring conditions of 1-15 (m3/h), Re = 478-7175 (-) and 13-15 (°C).

Keywords: heat pump; evaporator; shell side; pressure drop