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Search results for: PROBLEM SOLVING
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Fundamentals of Data-Driven Surrogate Modeling
PublicationThe primary topic of the book is surrogate modeling and surrogate-based design of high-frequency structures. The purpose of the first two chapters is to provide the reader with an overview of the two most important classes of modeling methods, data-driven (or approx-imation), as well as physics-based ones. These are covered in Chap-ters 1 and 2, respectively. The remaining parts of the book give an exposition of the specific aspects...
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Linear revitalization - problems and challenges. Discursive article
PublicationThe aim of the article, defined by the author as discursive, is to give the answer as to whether within ‘revitalization’ we should distinguish the notion of ‘linear revitalization’ – not yet defined in Polish and English-language literature. The author presents the thesis that we should do so by presenting the idea, its specific character and its role. This kind of action seems to have, in the author’s opinion, a positive influence...
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A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric Complex-Valued Matrices Obtained Using Higher-Order FEM
PublicationThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complex-valued matrices obtained using the higher-order finite-element method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the low-order...
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Scoreboard Architectural Pattern and Integration of Emotion Recognition Results
PublicationThis paper proposes a new design pattern, named Scoreboard , dedicated for applications solving complex, multi-stage, non-deterministic problems. The pattern provides a computational framework for the design and implementation of systems that integrate a large number of diverse specialized modules that may vary in accuracy, solution level, and modality. The Scoreboard is an extension of Blackboard design pattern and comes under...
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Hydraulic analysis of causes of washout of Gdynia-Orłowo seashore during the flood in the Kacza river estuary
PublicationIn July 2016 in the Three-city agglomeration a rainfall episode of over a day duration and 150 mm summary rainfall height, occurred. This situation, extreme as for Polish conditions, caused significant freshets in rivers and streams running into Gdansk Bay, the Baltic Sea, and serving as collectors of rainfall waters for the sea-coast towns. In many areas of the Three-city flood phenomena and overflows took place. The flood also...
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Reduced-Cost Two-Level Surrogate Antenna Modeling using Domain Confinement and Response Features
PublicationElectromagnetic (EM) simulation tools have become indispensable in the design of contemporary antennas. Still, the major setback of EM-driven design is the associated computational overhead. This is because a single full-wave simulation may take from dozens of seconds up to several hours, thus, the cost of solving design tasks that involve multiple EM analyses may turn unmanageable. This is where faster system representations (surrogates)...
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Planning the City Against Barriers. Enhancing the Role of Public Spaces
PublicationContemporary cities are being fragmented by growing number of technical barriers like roads, railways, infrastructural objects, that generate variety of problems of different nature. The aim of the research is to present the issues connected with such barriers in the city and the ways of solving them. Main problems are e.g.: the destruction of the complexity of urban fabric, functional disadvantages, environmental and landscape...
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Development of Intelligent Road Signs with V2X Interface for Adaptive Traffic Controlling
PublicationThe objective of this paper is to present a practical project of intelligent road signs, under which a series of new products for the regulation of traffic is being created. The engineering part of the project, described in this paper, was preceded by a series of experimental studies, the results of which were described in another paper accepted for publication at the MTS-ITS conference 2019, entitled "Comparative study on the effectiveness...
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Advanced Potential Energy Surfaces for Molecular Simulation
PublicationAdvanced potential energy surfaces are defined as theoretical models that explicitly include many-body effects that transcend the standard fixed-charge, pairwise-additive paradigm typically used in molecular simulation. However, several factors relating to their software implementation have precluded their widespread use in condensed-phase simulations: the computational cost of the theoretical models, a paucity of approximate models...
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Two-photon double ionization of atoms in attosecond x-ray radiation fields
PublicationWe consider two-photon double ionization of helium with 100, 200, and 400 eV excess energy for the two ejected electrons, corresponding to photon energies of 89.5, 139.5, and 239.5 eV, respectively. We focus on the case of ultrashort pulses (two oscillations of the field) and develop an approach to calculate the two-photon transition matrix elements within the lowest order of the time-dependent perturbation theory. One of the...
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Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant
PublicationIn the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR) working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller...
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Positive management of the university
PublicationAbstract: The prevailing view held at contemporary Polish universities is that their main goal is to achieve effects measured by indicators, which applies to each element of their mission: education, research and the third mission, whereas the means to accomplish this goal consists of increasing the requirements and motivating by the “carrot and stick” approach. That approach discounts the importance of building a positive relationship...
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Is it possible to create a unified urban greenery management system (UGMS) on a national scale? The concept for EU Member State of Poland
PublicationMotives: Currently developed urban greenery management systems (UGMS) are limited in scope and profiled towards solving particular issues. Moreover, due to the lack of common standards and solutions, UGMS implementation requires considerable financial effort, which is only feasible for wealthy urban centres. There is a need for universal, cost-effective technological solutions which could constitute a common urban green infrastructure...
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Verification of the method of reconstructing convective velocity fields on the basis of temperature fields in vertical, differential and equally heated, open and closed channels
PublicationThis paper describes a method of reconstructing velocity fields, i.e. a numerical reconstruction procedure (NRP) that involves the numerical processing of experimentally measured temperature distributions in free convection heat transfer. The NRP consists in solving only the continuity and Navier–Stokes equations with an additional source term. This term is proportional to a known temperature (e.g. from a thermal imaging camera)...
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The Changing Nature of In‐Between Spaces in the Transformation Process of Cities
PublicationIn the in‐between spaces of cities, there are many problems of various nature and scale: functional, spatial, economic, environmental, visual, and social. There are also some hidden potentials that can be activated. The aim of the article is to explore the possibilities of solving existing problems and to show the possibilities of using the potentials of in‐between spaces with regard to the changing nature of a city. The article,...
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ANALYSIS AND OPTIMIZATION OF ELECTRIC VEHICLE CHARGING PROCESSES IN TRANSACTIVE ENERGY SYSTEMS
PublicationThe implementation of smart charging of electric vehicles allows operators of local power networks and electricity suppliers to implement new business models for the interaction of electric vehicles with the network. In addition to the optimal selection of Microgrid capacities when charging electric vehicles, it is also important to use different charging methods. To satisfy the interests of all participants of local systems from...
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Improved Modeling of Microwave Structures Using Performance-Driven Fully-Connected Regression Surrogate
PublicationFast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulation-driven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive full-wave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are data-driven...
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Generalized regression neural network and fitness dependent optimization: Application to energy harvesting of centralized TEG systems
PublicationThe thermoelectric generator (TEG) system has attracted extensive attention because of its applications in centralized solar heat utilization and recoverable heat energy. The operating efficiency of the TEG system is highly affected by operating conditions. In a series-parallel structure, due to diverse temperature differences, the TEG modules show non-linear performance. Due to the non-uniform temperature distribution (NUTD) condition,...
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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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Remarks on use of the term “deep eutectic solvent” in analytical chemistry
PublicationAbout 20 years ago, Abbott and co-workers researched new solvents that were based on mixtures of choline chloride with urea and carboxylic acids and that were liquid at ambient temperature. The term “deep eutectic solvent” (DES) was later adopted for similar mixtures. As DESs have a number of interesting features, they quickly attracted the attention of researchers and found application in various branches of chemical and materials...
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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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On a flexomagnetic behavior of composite structures
PublicationThe popularity of the studies is getting further on the flexomagnetic (FM) response of nano-electro-magneto machines. In spite of this, there are a few incompatibilities with the available FM model. This study indicates that the accessible FM model is inappropriate when considering the converse magnetization effect that demonstrates the necessity and importance of deriving a new FM relation. Additionally, the literature has neglected...
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Revitalization of Residential Buildings Dating Back to the Late19th and Early 20th Century on the Example of “Willa Halina” in Sopot (Poland)
PublicationResidential buildings dating back to the late 19th and early 20th century constitute an important element of the urban composition of many European cities, often determining their overall spatial expression. These buildings often require revitalization and sometimes also reconstruction or extension. Such activities make it possible to restore historical buildings to their former glory, but also to create new architecture, inscribed...
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Performance-Driven Surrogate Modeling of High-Frequency Structures
PublicationThe development of modern high-frequency structures, including microwave and antenna components, heavily relies on full-wave electromagnetic (EM) simulation models. Notwithstanding, EM-driven design entails considerable computational expenses. This is especially troublesome when solving tasks that require massive EM analyzes, parametric optimization and uncertainty quantification be-ing representative examples. The employment of...
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Analysis of IPv6 handovers in IEEE 802.16 environment
PublicationThe second generation of WiMAX solutions, based on IEEE 802.16-2005 standard, offers limited mobility support. Unfortunately, after quickly changing the point of attachment on the WiMAX data link layer (DLL), very slow and inefficient IPv6 reconfiguration takes place. Delays introduced by automatic configuration (DHCPv6 and IPv6 protocols) and Mobile IPv6 can easily diminish or even render useless all benefits gained using the...
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Visual Attention Distribution Based Assessment of User's Skill in Electronic Medical Record Navigation
PublicationCurrently, the most precise way of reflecting the skills level is an expert’s subjective assessment. In this paper we investigate the possibility of the use of eye tracking data for scalar quantitative and objective assessment of medical staff competency in EMR system navigation. According to the experiment conducted by Yarbus the observation process of particular features is associated with thinking. Moreover, eye tracking is...
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Low-Cost Quasi-Global Optimization of Expensive Electromagnetic Simulation Models by Inverse Surrogates and Response Features
PublicationConceptual design of contemporary high-frequency structures is typically followed by a careful tuning of their parameters, predominantly the geometry ones. The process aims at improving the relevant performance figures, and may be quite expensive. The reason is that conventional design methods, e.g., based on analytical or equivalent network models, often only yield rough initial designs. This is especially the case for miniaturized...
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A review on analytical models of brushless permanent magnet machines
PublicationThis study provides an in-depth investigation of the use of analytical and numerical methods in analyzing electrical machines. Although numerical models such as the finite-element method (FEM) can handle complex geometries and saturation effects, they have significant computational burdens, are time-consuming, and are inflexible when it comes to changing machine geometries or input values. Analytical models based on magnetic equivalent...
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Cooperation areas between universities and industry - case studies in the area of civil engineering
PublicationThe paper describes the areas of cooperation between universities and industry in the area of civil engineering. Presented examples are related to didactics, research grants and commissioned works. On the basis of the authors own experiences the mutual benefits of cooperation in different areas are described. As well as the assessment criteria of the areas of cooperation by the scientific community. The first area of cooperation...
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Paradoxes in the engineering change management process
PublicationPurpose: The main purpose of this paper is to conceptualize and operationalize paradoxes that are significant in the engineering change management (ECM) process. The following research question was stated: What are the paradoxes that influence the ECM process, and how can they be measured? Design/methodology/approach: The study is divided into two parts: conceptualization and operationalization. Conceptualization involved a literature...
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Embedded device for indoor positioning of mobile terminals in ISM 2.4 GHz frequency band integrated with ESPAR antenna
PublicationIn the era of multifunctional mobile phones, wireless positioning is one of the most important branches of telecommunications development. This functionality is possible thanks to global positioning systems such as GPS, whose services are available to every average user. Global systems, however, suffer from their low accuracy in confined environments such as forests and building interiors. A popular...
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Load Testing of GFRP Composite U-Shape Footbridge
PublicationThe paper presents the scope of load tests carried out on an innovative shell composite footbridge. The tested footbridge was manufactured in one production cycle and has no components made from materials other than GFRP laminates and PET foam. The load tests, performed on a 14-m long structure, were the final stage of a research program in the Fobridge project carried out in cooperation with: Gdańsk University of Technology (leader),...
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Analysis of IPv6 Handovers in IEEE 802.16 environment
PublicationZaprezentowano pełną analizę wpływu poszczególnych faz procesu przełączania w warstwie drugiej i trzeciej na przerwy w transmisji wynikające ze zmiany stacji bazowej BS przez przemieszczający się węzeł ruchomy MN. Zaproponowano i przebadano symulacyjnie 10 scenariuszy przełączania, w tym 8 różnych algorytmów stanowej autokonfiguracji węzłów MN, wspierających protokół IPv6 w środowiskach sieci WiMAX. W badaniach wskazano na możliwości...
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TIME-DOMAIN NUMERICAL EVALUATION OF SHIP RESISTANCE AND MOTION IN REGULAR WAVES BY USING THE CFD URANS METHOD
PublicationTaking into account the International Maritime Organization's (IMO) strategy to radically reduce the...