Pavel Vazan

Prof. Pavel Vazan

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 March 2021 in Applied Sciences
Verified
Journal Article
Open access
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Zuzana ČerveňanskáZuzana Červeňanská
Zuzana Červeňanská
PVPavel Vazan
Pavel Vazan
Martin JuhásMartin Juhás
Martin Juhás
BJBohuslava Juhásová
Bohuslava Juhásová
The utilization of a specific priority rule in scheduling operations in flexible job shop systems strongly influences production goals. In a context of production control in real practice, production performance indicators are evaluated always en bloc. This paper addresses the multi-criteria evaluating five selected conflicting production objectives via scalar simulation-based optimization related to applied priority rule. It is connected to the discrete-event simulation model of a flexible job shop system with partially interchangeable workplaces, and it investigates the impact of three selected priority rules—FIFO (First In First Out), EDD (Earliest Due Date), and STR (Slack Time Remaining). In the definition of the multi-criteria objective function, two scalarization methods—Weighted Sum Method and Weighted Product Method—are employed in the optimization model. According to the observations, EDD and STR priority rules outperformed the FIFO rule regardless of the type of applied multi-criteria method for the investigated flexible job shop system. The results of the optimization experiments also indicate that the evaluation via applying multi-criteria optimization is relevant for identifying effective solutions in the design space when the specific priority rule is applied in the scheduling operations.

11 March 2021 in Energies
Verified
Journal Article
Open access
SKSzabolcs Kováč
Szabolcs Kováč
GMGerman Michaľčonok
German Michaľčonok
IHIgor Halenar
Igor Halenar
PVPavel Vazan
Pavel Vazan
Short-Term Load Prediction (STLP) is an important part of energy planning. STLP is based on the analysis of historical data such as outdoor temperature, heat load, heat consumer configuration, and the seasons. This research aims to forecast heat consumption during the winter heating season. By preprocessing and analyzing the data, we can determine the patterns in the data. The results of the data analysis make it possible to form learning algorithms for an artificial neural network (ANN). The biggest disadvantage of an ANN is the lack of precise guidelines for architectural design. Another disadvantage is the presence of false information in the analyzed training data. False information is the result of errors in measuring, collecting, and transferring data. Usually, trial error techniques are used to determine the number of hidden nodes. To compare prediction accuracy, several models have been proposed, including a conventional ANN and a wavelet ANN. In this research, the influence of different learning algorithms was also examined. The main differences were the training time and number of epochs. To improve the quality of the raw data and remove false information, the research uses the technology of normalizing raw data. The basis of normalization was the technology of the Z-score of the data and determination of the energy‒entropy ratio. The purpose of this research was to compare the accuracy of various data processing and neural network training algorithms suitable for use in data-driven (black box) modeling. For this research, we used a software application created in the MATLAB environment. The app uses wavelet transforms to compare different heat demand prediction methods. The use of several wavelet transforms for various wavelet functions in the research allowed us to determine the best algorithm and method for predicting heat production. The results of the research show the need to normalize the raw data using wavelet transforms. The sequence of steps involves following milestones: normalization of initial data, wavelet analysis employing quantitative criteria (energy, entropy, and energy‒entropy ratio), optimization of ANN training with information energy–entropy ratio, ANN training with different training algorithms, and evaluation of obtained outputs using statistical methods. The developed application can serve as a control tool for dispatchers during planning.

6 November 2020 in Applied Sciences
Verified
Journal Article
Open access
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Zuzana ČerveňanskáZuzana Červeňanská
Zuzana Červeňanská
JKJanette Kotianová
Janette Kotianová
PVPavel Vazan
Pavel Vazan
BJBohuslava Juhásová
Bohuslava Juhásová
Martin JuhásMartin Juhás
Martin Juhás
The article addresses an approximate solution to the multi-objective optimization problem for a black-box function of a manufacturing system. We employ the surrogate of the discrete-event simulation model of a batch production system in an analytical form. Integration of simulation, Design of Experiments methods, and Weighted Sum and Weighted Product multi-objective methods are used in an arrangement of a priori defined preferences to find a solution near the Pareto optimal solution in a criterion space. We compare the results obtained through the analytical approach to the outcomes of simulation-based optimization. The observed results indicate a possibility to apply the suitable analytical model for quickly finding the acceptable approximate solution close to the Pareto optimal front.

31 December 2024 in Sensors
Verified
Journal Article
Open access
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IHIgor Halenar
Igor Halenar
LHLenka Halenárová
Lenka Halenárová
Pavol TanuškaPavol Tanuška
Pavol Tanuška
PVPavel Vazan
Pavel Vazan
The core of this publication is the design of a system for evaluating the condition of production equipment and machines by monitoring selected parameters of the production process with an additional sensor subsystem. The main positive of the design is the processing of data from the sensor layer using artificial intelligence (AI) and expert systems (ESs) with the use of edge computing (EC). Sensor information is processed directly at the sensor level on the monitored equipment, and the results of the individual subsystems are stored in the form of triggers in a database for use in the predictive maintenance process. The whole solution includes the design of suitable sensors and of the implementation of the sensor layer, the description of data processing algorithms, the design on the communication infrastructure for the whole system, and tests in the form of experimental operation of the device in laboratory conditions. The solution includes the visualisation of the production system status for the operator using an interactive online map.

4 August 2023 in Electronics
Verified
Journal Article
Open access
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FBFedor Burčiar
Fedor Burčiar
PVPavel Vazan
Pavel Vazan
BJBohuslava Juhásová
Bohuslava Juhásová
Martin JuhásMartin Juhás
Martin Juhás
Real-time simulation and digital twin (DT) as a part of Industry 4.0 are becoming increasingly relevant, especially when considering production cycles. Most issues with production cycles arise from having a demand for customized production orders, while having nonmodular production lines with a medium-to-high complexity in the decision-making process. All these conditions lead to a possibility of unpredictable consequences. Being able to predict behavior and possible failure scenarios before the production starts has proven to save both costs and time. With an introduction of a new ISO standard which is solely focused on DT creation and sets a starting point for future research, researchers are finally able to focus on creating DT prototypes built for specific scenarios while maintaining the core concepts. This paper focuses on proposing strategies for DT and real-time simulation integration into production cycles, based on the new standards, which can be generalized and applied on a multitude of different systems with minimal changes. The proposed solutions offer different levels of human interaction with the Human–Machine Interfaces used in Cyber–Physical Systems created as a part of DT. Applicability of the solution has been verified based on the results of experiments carried out on the WITNESS Horizon simulation platform with utilization of the custom Order Manipulation Interface (OMI) application.

12 November 2024 in Preprints.org
Verified
Preprint
Open access
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IHIgor Halenar
Igor Halenar
LHLenka Halenárová
Lenka Halenárová
Pavol TanuškaPavol Tanuška
Pavol Tanuška
PVPavel Vazan
Pavel Vazan
The core of the publication is the design of a system for evaluating the condition of production equipment and machines by monitoring selected parameters of the production process with an additional sensor subsystem. The main positive of the design is the processing of data from the sensor layer using Artificial Intelligence (AI) and Expert Systems (ES) with the use of Edge Computing (EC). Sensor information is processed directly at the sensor level on the monitored equipment, and the results of the individual subsystems are stored in the form of triggers in a database for use in the predictive maintenance process. The whole solution includes the design of suitable sensors and the design of the implementation of the sensor layer, the description of data processing algorithms, the design on the communication infrastructure for the whole system, and tests in the form of experimental operation on the device in laboratory conditions. The solution includes visualization of the production system status for the operator using an interactive online map.