Search
displaying 1000 best results Help
Search results for: PROBLEMS
-
Application of Multivariate Analysis Methods in Welding Engineering
PublicationPhenomena and processes taking place during welding are usually very complex and, for this reason, should be described using multivariate methods. The article discusses the methodological basis and selected application areas as regards the solving of welding problems using statistical multivariate methods. In addition, the article presents exemplary applications of the design of experiment, multiple regression analysis, cluster...
-
Convergence of rational multistep methods of of Adams-Padé type
PublicationRational generalizations of multistep schemes, where the linear stiff part of a given problem is treated by an A-stable rational approximation, have been proposed by several authors, but a reasonable convergence analysis for stiff problems has not been provided so far. In this paper we directly relate this approach to exponential multistep methods, a subclass of the increasingly popular class of exponential integrators. This natural,...
-
Speed sensorless ac drive with inverter output filter and fault detection using load torque signal
PublicationIn this paper, a sensorless induction motor (IM) drive using speed observer system is presented. The system includes load torque computation for gear fault detection. Nonlinear control method is adopted for controlling the motor over a wide speed range. An LC filter for smoothing current and voltage waveforms is used at the output of the voltage inverter. The use of filter imposes more building of the used observer to avoid using...
-
Application of Maximum-Length Sequences to impulse response measurement of hydroacoustic communications systems
PublicationThere is a growing interest in digital transmission of telemetry data on ultrasonic waves. The dependence of signal attenuation on squared frequency, specific to the hy-droacoustic systems, induces problems that do not exist in monochromatic, narrowband radio communications systems. For adapting the transmission parameters to current propagation conditions, a precise knowledge of instantaneous changes of channel performances is...
-
Voltage Transients Transfer over Medium Voltage Instrument Transformers
PublicationThis paper presents voltage harmonic transfer accuracy problems through voltage transformers which are used in power quality monitoring systems in medium and high voltage grids. A simplified lumped parameters circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number voltage transformers typically used in medium voltage grid has been tested in the conducted disturbances...
-
A measurement system for children endurance tests
PublicationThere are a lot of ethical problems concerning the use of invasive methods for the measurement of a child's body response to physical exercise and physical training. The alternative is are non-invasive methods like ergospirometry or NIRS. The article presents a measurement system dedicated for children endurance tests, composed of a few non-invasive measurement modules, including a temperature measurement module. Temperature is...
-
Improving Effectiveness of SVM Classifier for Large Scale Data
PublicationThe paper presents our approach to SVM implementation in parallel environment. We describe how classification learning and prediction phases were pararellised. We also propose a method for limiting the number of necessary computations during classifier construction. Our method, named one-vs-near, is an extension of typical one-vs-all approach that is used for binary classifiers to work with multiclass problems. We perform experiments...
-
The impact of end-user participation in IT projects on product usability
PublicationMany companies implementing new IT projects encounter numerous problems with ensuring good final product usability. The strong market competition they experience often results in necessity of undertaking difficult decisions with regard to cost minimization. This may force cuts in usability expertise and consulting, most often by limiting end-user participation in the project. However, it may also result in serious consequences...
-
Recent progress in experimental studies of electrohydrodynamic flow in electrostatic precipitators
PublicationMany experimental, theoretical and numerical works were devoted to the electrohydrodynamic (EHD) flow generated in electrostatic precipitators (EPSs). The generally accepted conclusion from these studies is that the EHD flow plays an important role in the particle collection in ESPs. However, despite of the recent fast progress in numerical simulation and experimental techniques used in the ESPs studies many problems related to...
-
Parameter selection of an adaptive PI state observer for an induction motor
PublicationThe paper discusses problems connected with the parameters selection of the proportional-integral observer, designed for recon- struction of magnetic fluxes and angular speed of an induction motor. The selection is performed in several stages that are focused on different criteria. The first stage consists in selecting observer’s gains and provides desired dynamical properties, taking into consideration immunity to disturbances and...
-
Voltage Harmonics Transfer through Medium Voltage Instrument Transformers
PublicationVoltage transformers are widely used in power quality monitoring systems in medium and high voltage grids. This paper presents accuracy problems related to voltage harmonics transfer through instrument transformers. A simplified lumped-parameters wideband circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number of voltage transformers have been tested in the frequency...
-
Cold Cracking Of Underwater Wet Welded S355G10+N High Strength Steel
PublicationWater as the welding environment determines some essential problems influencing steel weldability. Underwater welding of high strength steel joints causes increase susceptibility to cold cracking, which is an effect of much faster heat transfer from the weld area and presence of diffusible hydrogen causing increased metal fragility. The paper evaluates the susceptibility to cold cracking of the high strength S355G10+N steel used,...
-
Overview of Scalability and Reliability Problem in SDN Networks
PublicationIn the paper an overview of scalability and reliability in the SDN (Software Defined Networks) networks has been presented. Problems and limitations for guaranteeing scalability and reliability in SDN networks have been indicated. Known methods for assuring scalability and reliability in SDN networks have been described. Projects from research communities for resolving issues with scalability and reliability in SDN networks have...
-
Mentor&Student Research Lab: new type of architectural and urban design workshops, new opportunities, valuable results
PublicationThe space around us has significantly changed during last years. Polish cities have undergone a major transformation following political, economical and social transition [8]. Similar change is noticeable at universities and their educational programmes for architecture and spatial planning students. Nowadays designers and activists tackle completely different problems and have different opportunities than their older colleagues...
-
QUEUE I
EventsFaculty of Applied Physics and Mathematics of Gdańsk Tech invites international students to the next summer school - Quantum and Molecules I (QUEUE I), organized within the ScienceApp project.
-
Introductory CDIO Project 2022/2023
e-Learning CoursesThe aim of this course is to make the students familiar with the team work to design, build and test simple electronic circuit. Also, how to write technical and engineering documentation taking in consideration electrical engineering, electronics, CAD and PCB design and computer simulation problems.
-
Introductory CDIO Project [Energy Technologies][2020/21]
e-Learning CoursesThe aim of this course is to make the students familiar with the team work to design, build and test simple electronic circuit. Also, how to write technical and engineering documentation taking in consideration electrical engineering, electronics, CAD and PCB design and computer simulation problems.
-
Introductory CDIO Project 2023/2024
e-Learning CoursesThe aim of this course is to make the students familiar with the team work to design, build and test simple electronic circuit. Also, how to write technical and engineering documentation taking in consideration electrical engineering, electronics, CAD and PCB design and computer simulation problems.
-
Heat Turbomachinery 2023_24
e-Learning CoursesBasics of thermodynamical cycles. Elements of turbine power plants. Fluid problems in turbomachinery. Theory of turbine stages. Turbine flow parts.
-
AGRO 2022
EventsTematyka konferencji dotyczy bezpieczeństwa żywnościowego oraz podjęcia działań w celu przeciwdziałania zmianom klimatu i ich skutkom.
-
Zastosowanie metody studium przypadku w kształceniu menedżerów
PublicationKształcenie z wykorzystaniem metod rozwiązywania problemów (problem-based learning) staje się coraz bardziej popularne na wszystkich poziomach kształcenia, również w edukacji biznesowej. Przykładem takiej metody jest studium przypadku (case study). Metoda studium przypadku pozwala na rozwijanie umiejętności i kompetencji wykorzystywanych przez menedżerów w ich pracy, np. umiejętności syntezy, identyfikacji problemów, czy podejmowania...
-
Numerical Methods
e-Learning CoursesNumerical Methods: for Electronics and Telecommunications students, Master's level, semester 1 Instructor: Michał Rewieński, Piotr Sypek Course description: This course provides an introduction to computational techniques for the simulation and modeling of a broad range of engineering and physical systems. Concepts and methods discussed are widely illustrated by various applications including modeling of integrated circuits,...
-
2022_Elective Design II_S_Hudnik_K_Zyczkowska_There is no Planet B
e-Learning CoursesThere is no Planet B The studio will use practical interventions to explore how climate change is affecting transformations in urban / non-urban space in Gdansk. Through the identification of problems and the importance of reading the consequences in space and architecture, students will learn about the method of opening a critical public debate. Through a variety of topics and actions – micro interventions, they will record their...
-
From Individual to Collective: Intelligence Amplification with Bio-Inspired Decisional DNA and its Extensions
PublicationIn nature, deoxyribonucleic acid (DNA) contains the genetic instructions used in the development and functioning of all known living organisms. The idea behind our vision is to develop an artificial system, an architecture that would support discovering, adding, storing, improving and sharing information and knowledge among agents and organizations through experience. We propose a novel Knowledge Representation (KR) approach in...
-
Regularized Local Basis Function Approach to Identification of Nonstationary Processes
PublicationThe problem of identification of nonstationary stochastic processes (systems or signals) is considered and a new class of identification algorithms, combining the basis functions approach with local estimation technique, is described. Unlike the classical basis function estimation schemes, the proposed regularized local basis function estimators are not used to obtain interval approximations of the parameter trajectory, but provide...
-
Electrochemical Evaluation of Sustainable Corrosion Inhibitors via Dynamic Electrochemical Impedance Spectroscopy
PublicationFinding suitable measurement methods for the effective management of electrochemical problems is of paramount importance, particularly for improving efficiency in corrosion protection. The need for accurate measurement techniques specific to nonstationary conditions has long been recognized, and promising approaches have emerged. This chapter introduces dynamic electrochemical impedance spectroscopy as a novel advancement in electrochemistry...
-
Contemporary Architectural Design in the Context of Historic Remains: The Case of the Old City of Gdańsk
PublicationThis article presents several examples of modern developments designed to preserve and coexist with fragments of historic brick buildings. These building projects each faced a similar task; to save and display the historical urban fabric, but they differed significantly in how they chose to achieve that goal. Not all of the projects presented in this study meet the requirements of the Venice Charter equally well. In this field,...
-
Accelerator of the entrepreneurship: suburbs in the coastal metropolis of GOM
PublicationPolish model of suburban structure is made of variety types of enterprises in different scales, and a range of housing. However this mass of unordered structure with its urban development problems, often leads to the establishment of business and also the development of local entrepreneurship. This article investigates SME sector located in the suburban area of costal metropolis GOM to prove the thesis that the positive effect...
-
Better polynomial algorithms for scheduling unit-length jobs with bipartite incompatibility graphs on uniform machines
PublicationThe goal of this paper is to explore and to provide tools for the investigation of the problems of unit-length scheduling of incompatible jobs on uniform machines. We present two new algorithms that are a significant improvement over the known algorithms. The first one is Algorithm 2 which is 2-approximate for the problem Qm|p j = 1, G = bisubquartic|Cmax . The second one is Algorithm 3 which is 4-approximate for the problem Qm|p...
-
Sustainable monument preservation in architectural education
PublicationThe aim of this article is both to present the need for changes in architectural and conservation education in a modern, rapidly changing world, as well as to outline solutions to this problem. In the modern world, the field of objects that one intends to protect is expanding. It is necessary to adapt the architectural education to these changes. Due to the current pace of social, political...
-
Stability of a truss under upward wind loading
PublicationThe present paper is devoted to the numerical investigations of stability of a truss under upward wind load. The truss is braced at its the upper cord. A structural variant including lateral braces, or lateral and torsional braces is considered. The research presents the problems of linear buckling and non-linear static analysis of the truss shell and beam model with geometric and material non-linearity are presented. The initial...
-
Analysis of measurement uncertainty for contact-less method used to measure the position of catenary contact wire, performed with the use of Monte Carlo method
PublicationCurrently the majority of main railway lines in Europe are electrified, and electric trains have the biggest share in the entire amount of rail transport. Reliability of electrified railways is closely related to the issue of supplying traction vehicles with energy. The problems connected with diagnostics of energy consumption node, namely the contact line and the current collector, are therefore of fundamental importance for maintaining...
-
Wireless paging system
PublicationAssistance to patients at hospitals and nursing homesoften encounters problems related to obtaining information onthe current needs of the patient. Traditionally, patient informshospital stuff by wire and wireless paging systems. WirelessPaging Systems allow one to overcome the limitations of theirwire counterparts, which include high installation costs (cabling)and lack of patient mobility. The main difference betweenpresented...
-
Traffic Noise Analysis Applied to Automatic Vehicle Counting and Classification
PublicationProblems related to determining traffic noise characteristics are discussed in the context of automatic dynamic noise analysis based on noise level measurements and traffic prediction models. The obtained analytical results provide the second goal of the study, namely automatic vehicle counting and classification. Several traffic prediction models are presented and compared to the results of in-situ noise level measurements. Synchronized...
-
Multi-objective optimization of microextraction procedures
PublicationOptimization of extraction process requiresfinding acceptable conditions for many analytes and goodperformance in terms of process time or solvent consumption. These optimization criteria are oftencontradictory to each other, the performance of the system in given conditions is good for some criteriabut poor for others. Therefore, such problems require special assessment tools that allow to combinethese contradictory criteria into...
-
Reject water and landfil leachate treatment with hydrophyte method - preliminary results
PublicationTreatment of landfill leachate (LL) and reject water (RWC) from dewatering of digested sludge in WWTPs have become one of the actual problems. Treatment of both types of wastewater is in many cases very costly and difficult due to quality and quantity fluctuations in time as well as high concentrations of specific pollutants. In case of our investigation the TSS concentration in RWC was two times higher than in LL. The shere of...
-
The Crisis of Marketing Communication in the Era of Social Media
PublicationThe articles examines the widely discussed in literature the problem of marketing communication crisis resulting from the changes of the environment. These changes generate both new problems and also new solutions, e.g. social media. The practicioners are pursuing both effective and efficient solutions, in relation to the difficulties encountered while achieving market objectives via traditional methods and channels. In accordance...
-
Fuzzy logic in controlling flexible manufacturing cell
PublicationIn the present work a controlling method based on fuzzy rule base is proposed. Practical approaches are developed and focused on real time problems related to flexible manufacturing cell. Techniques for design and implementation of fuzzy systems in the framework of control production and quality states are presented. Keywords: controlling, manufacturing system, fuzzy logic, turning, burnishingW artykule przedstawiono propozycję...
-
Use of Brassica plants in the phytoremediation and biofumigation processes
PublicationIn recent decades, serious contamination of soils by heavy metals has been reported. It is therefore a matter of urgency to develop a new and efficient technology for removing contaminants from soil. Another aspect to this problem is that environmental pollution decreases the biological quality of soil, which is why pesticides and fertilizers are being used in ever-larger quantities. The environmentally friendly solutions to these...
-
On practical application of Shannon theory to character recognition and more
PublicationLet us consider an optical character recognition system, which in particular can be used for identifying objects that were assigned strings of some length. The system is not perfect, for example, it sometimes recognizes wrongly the characters "Y" and "V". What is the largest set of strings of given length for the system under consideration, which can be mutually correctly recognized, and the corresponding objects correctly identified?...
-
Application of Multiplicative Drift Correction and Component Correction methods on simulated gas sensor array responses
PublicationSensor response drift is one of the most challenging problems in gas-analyzing systems. Such systems, commonly called electronic noses, are expected to be reliable and reproducible in the long term. Due to the drift phenomena, electronic noses usability is limited to the relatively short period of time, and frequent recalibrations of device are required. Because it is very hard to fabricate sensors without drift, this phenomenon...
-
Induction motor control application in high-speed train electric drive
PublicationThe chapter presents an application of induction motor mechanical speed and load torque observers in high-speed train drives. The observers are applied for a 1.2-MW electric drive with an induction motor. The goal of using such observers is to utilize computed variables for diagnostic purposes of speed sensors and torque transmission system. The concept of diagnostic system is presented in this paper, and proper criteria are proposed....
-
Improving the production planning and control process
PublicationFocusing the activities of a production business on the strategy based on quality entails orientation on meeting the expectations of the customers with respect to the product itself, and the terms of its delivery. The article notes the role of the production planning and control process in improving the quality of the business offer. It identifies the objectives set for the process from the perspective of meeting the expectations...
-
Influence of local bush wear on water lubricated sliding bearing load carrying capacity
PublicationOne of main problems concerning water-lubricated bearings is their durability. There are known cases of bearings with life time measured in decades, and some, whose refurbishment was necessary just days after start-up. Obtaining stable fluid film friction plays key role in the durability of these bearings. Unfortunately, their load-carrying capacity is limited due to water's low-viscosity. The conducted experimental...
-
Application of Web-GIS and Cloud Computing to Automatic Satellite Image Correction
PublicationRadiometric calibration of satellite imagery requires coupling of atmospheric and topographic parameters, which constitutes serious computational problems in particular in complex geographical terrain. Successful application of topographic normalization algorithms for calibration purposes requires integration of several types of high-resolution geographic datasets and their processing in a common context. This paper presents the...
-
Technological vs. Non-Technological Mindsets: Learning From Mistakes, and Organizational Change Adaptability to Remote Work
PublicationThe permanent implementation of the change in working methods, e.g., working in the virtual space, is problematic for some employees and, as a result, for management leaders. To explore this issue deeper, this study assumes that mindset type: technological vs. non-technological, may influence the organizational adaptability to change. Moreover, the key interest of this research is how non-technological mindsets...
-
Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table
PublicationTheoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important...
-
Troubleshooting of the determination of bisphenol A at ultra-trace levels by liquid chromatography and tandem mass spectrometry
PublicationDetermination of trace amounts of bisphenol A (BPA) may cause problems mainly related to the presence of BPA in solvents (even in LC-MS grade), laboratory vessels, and plastic equipment used for sample preparation. Variable and sometimes significant amounts of BPA present in the background cause problems in obtaining good repeatability of measurements at the ultra-trace levels. Such observations (i.e., poor repeatability of results)...
-
Bartosz Sawik
PeopleDr Bartosz Sawik is a Professor at the Department of Business Informatics and Engineering Management, AGH University of Science and Technology, Krakow, Poland and at the Institute of Smart Cities, GILT-OR Group, Department of Statistics, Computer Science and Mathematics, Public University of Navarre, Pamplona, Spain. He is a Visiting Researcher at the University of California, Berkeley, USA. He has a Ph.D. and a M.Sc. and Eng....
-
Estimation of a Stochastic Burgers' Equation Using an Ensemble Kalman Filter
PublicationIn this work, we consider a difficult problem of state estimation of nonlinear stochastic partial differential equations (SPDE) based on uncertain measurements. The presented solution uses the method of lines (MoL), which allows us to discretize a stochastic partial differential equation in a spatial dimension and represent it as a system of coupled continuous-time ordinary stochastic differential equations (SDE). For such a system...