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Search results for: reliability
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Assessing Tram Infrastructure Safety Using the Example of the City of Gdańsk
PublicationAnalysis of Gdańsk’s tram network statistics shows that incidents are quite frequent (about 650 within 5 years) and mostly involve collisions and crashes. As well as reducing the tram systems’ efficiency and reliability, incidents have a nega-tive effect on road safety. As Polish cities extend their tram networks, they must also ensure that their existing networks are safe. This is to be achieved by conducting safety assessments....
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The High Quality Business School Academic Teacher of the 21st Century – Polish Students’ Perspective
PublicationThe literature shows that the success and competence of future managers depend on the quality of their academic teachers. Moreover high quality study requires high quality lecturing/teaching that creates an environment in which deep learning outcomes are made possible for students. The aim was to identify the characteristics of the academic teacher working at business schools, according to the expectations of Polish students...
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Low-Cost Yield-Driven Design of Antenna Structures Using Response-Variability Essential Directions and Parameter Space Reduction
PublicationQuantifying the effects of fabrication tolerances and uncertainties of other types is fundamental to improve antenna design immunity to limited accuracy of manufacturing procedures and technological spread of material parameters. This is of paramount importance especially for antenna design in the industrial context. Degradation of electrical and field properties due to geometry parameter deviations often manifests itself as, e.g.,...
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Multi-objective optimization of expensive electromagnetic simulation models
PublicationVast majority of practical engineering design problems require simultaneous handling of several criteria. For the sake of simplicity and through a priori preference articulation one can turn many design tasks into single-objective problems that can be handled using conventional numerical optimization routines. However, in some situations, acquiring comprehensive knowledge about the system at hand, in particular, about possible...
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Advancing electrochemical impedance analysis through innovations in the distribution of relaxation times method
PublicationElectrochemical impedance spectroscopy (EIS) is widely used in electrochemistry, energy sciences, biology, and beyond. Analyzing EIS data is crucial, but it often poses challenges because of the numerous possible equivalent circuit models, the need for accurate analytical models, the difficulties of nonlinear regression, and the necessity of managing large datasets within a unified framework. To overcome these challenges, non-parametric...
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Crafting an ultrashort workplace incivility scale and determining cutoffs for varied risk levels through item response theory
PublicationWorkplace incivility (WI), characterized by disrespectful or rude behavior in the workplace, is linked to poor mental health and overall well-being. The Workplace Incivility Scale (WIS) is a popular 7-item measure for assessing WI. There is a current need for an ultrashort conceptually clear version of the WIS. In addition, the cutoffs for varied at-risks of WI, requiring intervention, remains unknown. Using data from 426 employees...
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Optimization of constitutive law for objective numerical modeling of knitted fabric
PublicationThis paper discusses the problem of macroscopic modeling a knitted technical fabric with the aim to determine a constitutive law for adequately modeling the material response under real-life load. As phenomenological, hyperelastic material laws reveal different parameters due to different test modalities used to identify such parameters, an optimization scheme is proposed to determine an objective solution. The study is conducted...
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PSYCHOMETRIC PROPERTIES OF THE POLISH VERSION OF THE GENERALIZED ANXIETY DISORDER 7-ITEM SCALE (GAD-7) IN A NON-CLINICAL SAMPLE OF EMPLOYEES DURING PANDEMIC CRISIS
PublicationObjectives: The COVID-19 outbreak is an example of a crisis that triggered an increase in generalized anxiety disorder. The study aims to validate the Polish version of the Generalized Anxiety Disorder 7-item scale (GAD-7) by Spitzer et al. among a non-clinical sample of employees and examine the invariance depending on the gender and age of working adults. Material and Methods: For assessing factor structure of the Polish version...
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On Memory-Based Precise Calibration of Cost-Efficient NO2 Sensor Using Artificial Intelligence and Global Response Correction
PublicationNitrogen dioxide (NO2) is a prevalent air pollutant, particularly abundant in densely populated urban regions. Given its harmful impact on health and the environment, precise real-time monitoring of NO2 concentration is crucial, particularly for devising and executing risk mitigation strategies. However, achieving precise measurements of NO2 is challenging due to the need for expensive and cumbersome equipment. This has spurred...
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OOA-modified Bi-LSTM network: An effective intrusion detection framework for IoT systems
PublicationCurrently, the Internet of Things (IoT) generates a huge amount of traffic data in communication and information technology. The diversification and integration of IoT applications and terminals make IoT vulnerable to intrusion attacks. Therefore, it is necessary to develop an efficient Intrusion Detection System (IDS) that guarantees the reliability, integrity, and security of IoT systems. The detection of intrusion is considered...
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Statistical Data Pre-Processing and Time Series Incorporation for High-Efficacy Calibration of Low-Cost NO2 Sensor Using Machine Learning
PublicationAir pollution stands as a significant modern-day challenge impacting life quality, the environment, and the economy. It comprises various pollutants like gases, particulate matter, biological molecules, and more, stemming from sources such as vehicle emissions, industrial operations, agriculture, and natural events. Nitrogen dioxide (NO2), among these harmful gases, is notably prevalent in densely populated urban regions. Given...
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Sustainable nitrogen removal in anammox-mediated systems: Microbial metabolic pathways, operational conditions and mathematical modelling
PublicationAnammox-mediated systems have attracted considerable attention as alternative cost-effective technologies for sustainable nitrogen (N) removal from wastewater. This review comprehensively highlights the importance of understanding microbial metabolism in anammox-mediated systems under crucial operation parameters, indicating the potentially wide applications for the sustainable treatment of N-containing wastewater. The partial...
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Low-Cost Design Optimization of Microwave Passives Using Multi-Fidelity EM Simulations and Selective Broyden Updates
PublicationGeometry parameters of contemporary microwave passives have to be carefully tuned in the final stages of their design process to ensure the best possible performance. For reliability reasons, the tuning has to be to be carried out at the level of full-wave electromagnetic (EM) simulations. This is because traditional modeling methods are incapable of quantifying certain phenomena that may affect operation and performance of these...
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A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublicationMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
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Application of COSMO-RS-DARE as a Tool for Testing Consistency of Solubility Data: Case of Coumarin in Neat Alcohols
PublicationCoumarin is a naturally occurring lactone-type benzopyrone with various applications in the pharmaceutical, food, perfume, and cosmetics industries. This hydrophobic compound is poorly soluble in water but dissolves well in protic organic solvents such as alcohols. Despite the extensive use of coumarin, there are only a few reports documenting its solubility in organic solvents, and some reported data are incongruent, which...
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A Comparative Study of Fuzzy SMC with Adaptive Fuzzy PID for Sensorless Speed Control of Six-Phase Induction Motor
PublicationMulti-phase motors have recently replaced three-phase induction motors in a variety of applications due to the numerous benefits they provide, and the absence of speed sensors promotes induction motors with variable speed drives. Sensorless speed control minimizes unnecessary speed encoder cost, reduces maintenance, and improves the motor drive’s reliability. The performance comparison of the fuzzy sliding mode controller (FSMC)...
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Broken rotor bar impact on sensorless control of induction machine
PublicationThe aim of the research is analysis of the sensorless control system of induction machine with broken rotor for diagnostic purposes. Increasing popularity of sensorless controlled variable speed drives requires research in area of reliability, range of stable operation, fault symptoms and application of diagnosis methods. T transformation (Cunha et al.,2003) used for conversion of instantaneous rotor currents electrical circuit...
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The rigid and flexible road pavements in terms of life cycle costs
PublicationThe cost of road pavement construction, its durability and reliability depends on many factors, including: the scope and detail of the technical design, quality of work but also the scope of works related to its maintenance, conservation and operation. Determining the amount of rational expenses, in terms of the life cycle cost of the pavement, requires determination and consideration of the above issues, already at the planning...
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Response of cylindrical steel tank under stochastically generated non-uniform earthquake excitation
PublicationCylindrical steel tanks are very important structures in industrial facilities since their application is related to storing different types of products. Their safety and reliability have become a crucial issue because any damage may cause significant consequences, including ecological disaster. The most dangerous dynamic load acting on cylindrical steel tanks is related to earthquakes, especially that the seismic excitation may...
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Tensile and Fatigue Behavior of Additive Manufactured Polylactide
PublicationThis article presents the results of monotonic tensile and fatigue tests conducted on commercial polylactide or polylactic acid (PLA). The results of fatigue tests for this material present in the literature are limited, especially for additive manufactured elements. The specimens were manufactured using the injection molding and the fused filament fabrication (FFF) method. The FFF specimens were divided into five subgroups, depending...
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Reinforced Secure Gossiping Against DoS Attacks in Post-Disaster Scenarios
PublicationDuring and after a disaster, the perceived quality of communication networks often becomes remarkably degraded with an increased ratio of packet losses due to physical damages of the networking equipment, disturbance to the radio frequency signals, continuous reconfiguration of the routing tables, or sudden spikes of the network traffic, e.g., caused by the increased user activity in a post-disaster period. Several techniques have...
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Investigation of environmental influences to the precise GNNS solutions
PublicationThe results presented in this paper concern investigation of environmental influences to GNNS coordinates on the example of ASG-EUPOS network. The problem of the impact of environmental effects is crucial for observing gravity. Satellite systems are not as susceptible to changes in local hydrology or atmospheric effects, although significant influences are clearly visible in the change of coordinates. The authors analyzed daily...
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Fast and reliable knowledge-based design closure of antennas by means of iterative prediction-correction scheme
PublicationA novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios. The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels...
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Accelerated Gradient-Based Optimization of Antenna Structures Using Multi-Fidelity Simulations and Convergence-Based Model Management Scheme
PublicationThe importance of numerical optimization has been steadily growing in the design of contemporary antenna structures. The primary reason is the increasing complexity of antenna topologies, [ a typically large number of adjustable parameters that have to be simultaneously tuned. Design closure is no longer possible using traditional methods, including theoretical models or supervised parameter sweeping. To ensure reliability, optimization...
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Computationally Efficient Surrogate-Assisted Design of Pyramidal-Shaped 3D Reflectarray Antennas
PublicationReflectarrays (RAs) have been attracting considerable interest in the recent years due to their appealing features, in particular, a possibility of realizing pencil-beam radiation patterns, as in the phased arrays, but without the necessity of incorporating the feeding networks. These characteristics make them attractive solutions, among others, for satellite communications or mobile radar antennas. Notwithstanding, available microstrip...
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Microseismic Monitoring of Hydraulic Fracturing - Data Interpretation Methodology With an Example from Pomerania
PublicationMicroseismic monitoring is a method for localizing fractures induced by hydraulic fracturing in search for shell gas. The data is collected from an array of geophones deployed on the surface or underground. Ground vibrations are recorded and analysed for fracture location, magnitude and breakage mechanism. For successful microseismic monitoring one need a velocity model of underlying formations. The model is further tuned with...
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Mechanistic insights and atmospheric implications of the degradation reaction of 3-methoxy-1-propanol by reaction with hydroxyl radicals and identification of the end products in the presence of O2/NO
PublicationThe study investigated the degradation of 3-methoxy-1-propanol (3M1P) by OH using the M06-2X/6-311++G(d,p) level, with CCSD(T) single-point corrections. We focused on hydrogen atom abstraction from various alkyl groups within the molecule. The rate coefficient for 3M1P degradation was calculated from the sum of the rate coefficients corresponding to the removal of H-atoms from primary (-CH3), secondary (-CH2-), tertiary (-CH<),...
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Dimensionality-Reduced Antenna Modeling with Stochastically Established Constrained Domain
PublicationOver the recent years, surrogate modeling methods have become increasingly widespread in the design of contemporary antenna systems. On the one hand, it is associated with a growing awareness of numerical optimization, instrumental in achieving high-performance structures. On the other hand, considerable computational expenses incurred by massive full-wave electromagnetic (EM) analyses, routinely employed as a major design tool,...
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Machine-learning-based precise cost-efficient NO2 sensor calibration by means of time series matching and global data pre-processing
PublicationAir pollution remains a considerable contemporary challenge affecting life quality, the environment, and economic well-being. It encompasses an array of pollutants—gases, particulate matter, biological molecules—emanating from sources such as vehicle emissions, industrial activities, agriculture, and natural occurrences. Nitrogen dioxide (NO2), a harmful gas, is particularly abundant in densely populated urban areas. Given its...
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Direct Constraint Control for EM-Based Miniaturization of Microwave Passives
PublicationHandling constraints imposed on physical dimensions of microwave circuits has become an important design consideration over the recent years. It is primarily fostered by the needs of emerging application areas such as 5G mobile communications, internet of things, or wearable/implantable devices. The size of conventional passive components is determined by the guided wavelength, and its reduction requires topological modifications,...
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Functional safety and human factors
PublicationRozdział przedstawia istotny problem uwzględnienia czynników ludzkich (H&OF) w analizie bezpieczeństwa funkcjonalnego, które wpływają istotnie na bezpieczeństwo przemysłowych obiektów podwyższonego ryzyka, nie ujęty jednak w normach bezpieczeństwa funkcjonalnego. Przedstawia się metody analizy niezawodności człowieka (HRA) w kontekście tych czynników, które wpływają na błędy człowieka. Czynniki ludzkie i organizacyjne powinny być...
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EM-Driven Size Reduction and Multi-Criterial Optimization of Broadband Circularly-Polarized Antennas Using Pareto Front Traversing and Design Extrapolation
PublicationMaintaining small size has become an important consideration in the design of contemporary antenna structures. In the case of broadband circularly polarized (CP) antennas, miniaturization is a challenging process due to the necessity of simultaneous handling of electrical and field properties (reflection, axial ratio, gain), as well as ensuring sufficient frequency range of operation, especially at the lower edge of the antenna...
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Psychometric properties of the polish version of the job-related affective well-being scale
PublicationObjectives: The aim of this study was to verify psychometric properties of the Polish version of the Job-related Affective Well-being Scale (JAWS). Specifically, theoretical 4-factor structure (based on the dimensions of pleasure and arousal) and reliability of the original – 20-item JAWS (van Katwyk et al., 2000) and the shortened – 12-item (Schaufeli and Van Rhenen, 2006) versions were tested. Material and Methods: Two independent...
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Rapid design optimization of antennas using variable-fidelity EM models and adjoint sensitivities
PublicationPurpose – Development of techniques for expedited design optimization of complex and numerically expensive electromagnetic (EM) simulation models of antenna structures validated both numerically and experimentally. The paper aims to discuss these issues. Design/methodology/approach – The optimization task is performed using a technique that combines gradient search with adjoint sensitivities, trust region framework, as well as...
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Advanced sensitivity analysis of the impact of the temporal distribution and intensity of rainfall on hydrograph parameters in urban catchments
PublicationKnowledge of the variability of the hydrograph of outflow from urban catchments is highly important for measurements and evaluation of the operation of sewer networks. Currently, hydrodynamic models are most frequently used for hydrograph modeling. Since a large number of their parameters have to be identified, there may be problems at the calibration stage. Hence, sensitivity analysis is used to limit the number of parameters....
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Design centering of compact microwave components using response features and trust regions
PublicationFabrication tolerances, as well as uncertainties of other kinds, e.g., concerning material parameters or operating conditions, are detrimental to the performance of microwave circuits. Mitigating their impact requires accounting for possible parameter deviations already at the design stage. This involves optimization of appropriately defined statistical figures of merit such as yield. Alt-hough important, robust (or tolerance-aware)...
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Fast multi-objective design optimization of microwave and antenna structures using data-driven surrogates and domain segmentation
PublicationPurpose Strategies and algorithms for expedited design optimization of microwave and antenna structures in multi-objective setup are investigated. Design/methodology/approach Formulation of the multi-objective design problem oriented towards execution of the population-based metaheuristic algorithm within the segmented search space is investigated. Described algorithmic framework exploit variable fidelity modeling, physics- and...
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Cost-Efficient EM-Driven Size Reduction of Antenna Structures by Multi-Fidelity Simulation Models
PublicationDesign of antenna systems for emerging application areas such as the Internet of Things (IoT), fifth generation wireless communications (5G), or remote sensing, is a challenging endeavor. In addition to meeting stringent performance specifications concerning electrical and field properties, the structure has to maintain small physical dimensions. The latter normally requires searching for trade-off solutions because miniaturization...
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GNSS reference solution for permanent sition stability monitoring and geodynamical investigations - the ASG-EUPOS case study
PublicationThe aim of this paper is to present the strategy of determination of the reference solution for the ASG-EUPOS (ActiveGeodetic Network – European Position Determination System) coordinate monitoring system. ASG-EUPOS is a network of permanent GNSS (Global Navigation Satellite System) stations controlled by the Polish Head Office of Geodesy and Cartography (HOGC), which main role is to realize the ETRS89 (European Terrestrial Reference...
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Global EM-Driven Optimization of Multi-Band Antennas Using Knowledge-Based Inverse Response-Feature Surrogates
PublicationElectromagnetic simulation tools have been playing an increasing role in the design of contemporary antenna structures. The employment of electromagnetic analysis ensures reliability of evaluating antenna characteristics but also incurs considerable computational expenses whenever massive simulations are involved (e.g., parametric optimization, uncertainty quantification). This high cost is the most serious bottleneck of simulation-driven...
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Rapid Design Centering of Multi-Band Antennas Using Knowledge-Based Inverse Models and Response Features
PublicationAccounting for manufacturing tolerances as well as uncertainties concerning operating conditions and material parameters is one of the important yet often neglected aspects of antenna development. Appropriate quantification of uncertainties allows for estimating the fabrication yield but also to carry out robust design (e.g., yield maximization). For reliability reasons, statistical analysis should be executed at the accuracy level...
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An adaptive-noise Augmented Kalman Filter approach for input-state estimation in structural dynamics
PublicationThe establishment of a Digital Twin of an operating engineered system can increase the potency of Structural Health Monitoring (SHM) tools, which are then bestowed with enhanced predictive capabilities. This is particularly relevant for wind energy infrastructures, where the definition of remaining useful life is a main driver for assessing the efficacy of these systems. In order to ensure a proper representation of the physical...
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Measurements in civil engineering, transport, environmental engineering, mining and power engineering 22/23
e-Learning CoursesThe course is primarily open to all PhD students at Gdansk University of Technology. This course is compulsory for PhD students assigned to Civil Engineering and Transport as well as Environmental Engineering, Mining and Power Engineering tracks at Doctoral School of GUT. This course allows the PhD students to obtain the knowledge related to the experimental equipment and types of experiments carried out at GUT in the field of...
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Measurements in civil engineering, transport, environmental engineering, mining and power engineering 23/24
e-Learning CoursesThe course is primarily open to all PhD students at Gdansk University of Technology. This course is compulsory for PhD students assigned to Civil Engineering and Transport as well as Environmental Engineering, Mining and Power Engineering tracks at Doctoral School of GUT. This course allows the PhD students to obtain the knowledge related to the experimental equipment and types of experiments carried out at GUT in the field of...
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Measurements in civil engineering, transport, environmental engineering, mining and power engineering 24/25
e-Learning CoursesThe course is primarily open to all PhD students at Gdansk University of Technology. This course is compulsory for PhD students assigned to Civil Engineering and Transport as well as Environmental Engineering, Mining and Power Engineering tracks at Doctoral School of GUT. This course allows the PhD students to obtain the knowledge related to the experimental equipment and types of experiments carried out at GUT in the field of...
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Computer controlled systems - 2022/2023
e-Learning Coursesmateriały wspierające wykład na studiach II stopnia na kierunku ACR pod tytułem komputerowe systemy automatyki 1. Computer system – controlled plant interfacing technique; simple interfacing and with both side acknowledgement; ideas, algorithms, acknowledge passing. 2. Methods of acknowledgement passing: software checking and passing, using interrupt techniques, using readiness checking (ready – wait lines). The best solution...
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CCS-lecture-2023-2024
e-Learning Coursesmateriały wspierające wykład na studiach II stopnia na kierunku ACR pod tytułem komputerowe systemy automatyki 1. Computer system – controlled plant interfacing technique; simple interfacing and with both side acknowledgement; ideas, algorithms, acknowledge passing. 2. Methods of acknowledgement passing: software checking and passing, using interrupt techniques, using readiness checking (ready – wait lines). The best solution optimization...
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Przygotowanie, realizacja i ocena pomiarów terenowych do identyfikacji oporności hydraulicznej sieci wodociągowej
PublicationW procesie tworzenia komputerowego modelu przepływów (KMP) jednym z wiodących zadań jest przygotowanie i realizacja pomiarów terenowych w celu identyfikacji oporności hydraulicznej czynnej sieci wodociągowej. Motywacją autora do przedstawienia zasad postępowania w tym zakresie jest narastająca niefrasobliwość twórców KMP, którzy w nieuprawniony sposób używają paramodeli do rozwiązywania problemów inżynierskich. W pracy zdefiniowano...
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On deterministic procedures for low-cost multi-objective design optimization of miniaturized impedance matching transformers
PublicationPurpose This paper aims to investigate deterministic strategies for low-cost multi-objective design optimization of compact microwave structures, specifically, impedance matching transformers. The considered methods involve surrogate modeling techniques and variable-fidelity electromagnetic (EM) simulations. In contrary to majority of conventional approaches, they do not rely on population-based metaheuristics, which permit lowering...
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Uncertainty Quantification of Additive Manufacturing Post-Fabrication Tuning of Resonator-Based Microwave Sensors
PublicationReconfigurability, especially in terms of the ability of adjusting the operating frequency, has become an important prerequisite in the design of modern microwave components and systems. It is also pertinent to microwave sensors developed for a variety of applications such as characterization of material properties of solids or liquids. This paper discusses uncertainty quantification of additive-manufacturing-based post-fabrication...