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Search results for: GRADIENT MAP
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Rapid design optimization of compact couplers using response features and adjoint sensitivities
PublicationA technique for rapid EM-driven design optimization of compact microwave couplers is presented. Our approach exploits response features and adjoint sensitivities and allows for low-cost design closure both in terms of performance enhancement and structure miniaturization. It is demonstrated using a compact rat-race coupler working at 1 GHz and compared to adjoint-based gradient optimization.
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Voltage and Reactive Power Load Flow Optimization in the Power System Using Fuzzy Logic
PublicationThe paper presents issues related to voltage control in the power system. An original method of reactive power flow optimization is considered, which leads to improved voltages in the power system and reduced active power losses. The optimization method is based on a procedure that employs fuzzy logic and is supported by a gradient search algorithm. The method has been implemented in PLANS software and verified.
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Vibration Surveillance System with Variable Stiffness Holder for Milling Flexible Details
PublicationEfficient milling of the flexible details (i.e. rotor blades, thin-walled elements) using slender ball-end tools is a difficult task due to possibility of vibration occurrence. Because of the existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may lose stability and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency...
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Personalized prediction of the secondary oocytes number after ovarian stimulation: A machine learning model based on clinical and genetic data
PublicationControlled ovarian stimulation is tailored to the patient based on clinical parameters but estimating the number of retrieved metaphase II (MII) oocytes is a challenge. Here, we have developed a model that takes advantage of the patient’s genetic and clinical characteristics simultaneously for predicting the stimulation outcome. Sequence variants in reproduction-related genes identified by next-generation sequencing were matched...
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Online urban acoustic noise monitoring system
PublicationConcepts and implementation of the Online Urban Noise Monitoring System are presented. Principles of proposed solution used for dynamic acoustical maps creating are discussed. The architecture of the system and the data acquisition scheme are described. The concept of noise mapping, based on noise source model and propagation simulations, was developed and employed in the system. Dynamic estimation of noise source parameters utilized...
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Sea surface temperature distribution during upwelling along the Polish Baltic coast
PublicationAmong over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers...
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A note on an approximative scheme of finding almost homoclinic solutions for Newtonian systems
PublicationIn this work we will be concerned with the existence of an almost homoclinic solution for a perturbed Newtonian system in a finite dimensional space. It is assumed that a potential is C^1 smooth and its gradient is bounded with respect to a time variable. Moreover, a forcing term is continuous, bounded and squere integrable. We will show that the appproximative scheme due to J. Janczewska for a time periodic potential extends to...
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Tracking body movement for radio channel measurements in BAN with indoor positioning system
PublicationThis paper presents indoor positioning system based on inertial navigation with additional distance measurements using UWB modems and map matching to increase accuracy and eliminate position drift. Such system may be used to track position of human body during radio channel measurements for body area networks. Performance of proposed system and limitations caused by inertial navigation are briefly described.
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GPU-accelerated finite element method
PublicationIn this paper the results of the acceleration of computations involved in analysing electromagnetic problems by means of the finite element method (FEM), obtained with graphics processors (GPU), are presented. A 4.7-fold acceleration was achieved thanks to the massive parallelization of the most time-consuming steps of FEM, namely finite-element matrix-generation and the solution of a sparse system of linear equations with the...
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Natural convection in symmetrically heated vertical channels
PublicationThe study describes natural convection through a vertical channel, open on four sides and bound by two isothermal walls. Both balancing and infrared experimental investigations were performed in air (Pr = 0.71) to estimate the impact of channel width s and wall-to-ambient temperature difference (tw - t∞) on natural convective heat transfer, the formation of air flow patterns and the rate of flow pattern formation. The study was...
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Modelling of shear zones in granular materials within hypoplasticity.
PublicationW artykule przedstawiono wyniki numerycznej analizy ściskania w płaskim stanie odkształcenia dla materiałów granulowanych. Obliczenia przeprowadzono z modelem hipoplastycznym rozszerzonym o obroty, nielokalność i gradienty odkształceń.
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Glosa aprobująca do wyroku Izby Karnej Sądu Najwyższego z 29 maja 2018 r. o sygn. akt II KK 99/18. A comment of approval on the verdict of 29 May 2018 issued by the Criminal Law Chamber of the Polish Supreme Court (II KK 99/18).
Publication"Glosowany wyrok Sądu Najwyższego dotyczy problematyki orzekania o czynach przeciwko mieniu, w stosunku do których od 9 listopada 2013 r. kryterium uznania danego czynu za przestępstwo albo za wykroczenie stanowi określony w kodeksie wykroczeń wskaźnik minimalnego wynagrodzenia za pracę. We wskazanym zakresie należy mieć na uwadze minimalne wynagrodzenie z daty orzekania w przedmiocie odpowiedzialności za taki czyn, a nie z...
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Identyfikacja terenu za pomocą autonomicznego robota
PublicationW pracy rozważane jest zagadnienie identyfikacji nieznanego terenuprzy pomocy autonomicznego robota o ograniczonym zasięguwidzialności. Przyjęty model matematyczny zakłada, że teren mapostać ograniczonej dwuwymiarowej mapy podzielonej na identycznekwadratowe obszary (pola) przylegające do siebie bokami. Zadaniemautonomicznego robota, którego zasięg widzialności ogranicza siedo pól przylegających do miejsca, w którym się znajduje,...
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Najważniejsze fitopatogeny wirusowe, grzybowe i bakteryjne atakujące rośliny rolnicze w klimacie umiarkowanym
PublicationZakażenia fitopatogenami stanowią poważne zagrożenie dla rolnictwa oraz przemysłu opartego na produktach roślinnych. Często prowadzą do ogromnych strat na rynku wynikających z przymusowego usuwania zakażonych roślin i plonów, mogą mieć negatywny wpływ na środowisko, a nawet powodować zatrucia wśród ludzi, oraz zwierząt. Kluczowym wydaje się więc dogłębne poznanie fitopatogenów i w dalszej perspektywie opracowanie skutecznej ochrony...
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Assessment of Alterations in Settlement Patterns of Agricultural Landscape in the Example of Kashubia in Poland
PublicationTraditional agricultural landscapes are heavily exposed to change due to their relatively low agricultural productivity. However, they represent cultural values of great importance in maintaining the resilience of the environment and society. Although their cultural potential is important for sustainable development, it is still insufficiently recognized. The article fills this gap by examining old farmstead buildings as a distinguishing...
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Expedited optimization of antenna input characteristics with adaptive Broyden updates
PublicationSimulation-driven adjustment of geometry and/or material parameters is a necessary step in the design of contemporary antenna structures. Due to their topological complexity, other means, such as supervised parameter sweeping, does not usually lead to satisfactory results. On the other hand, rigorous numerical optimization is computationally expensive due to a high cost of underlying full-wave electromagnetic (EM) analyses, otherwise...
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Reinforcement Learning Algorithm and FDTD-based Simulation Applied to Schroeder Diffuser Design Optimization
PublicationThe aim of this paper is to propose a novel approach to the algorithmic design of Schroeder acoustic diffusers employing a deep learning optimization algorithm and a fitness function based on a computer simulation of the propagation of acoustic waves. The deep learning method employed for the research is a deep policy gradient algorithm. It is used as a tool for carrying out a sequential optimization process the goal of which is...
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Topological modifications for performance improvement and size reduction of wideband antenna structures
PublicationCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
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Social learning and knowledge flows in cluster initiatives, In: Sanz S.C., Blanco F.P., Urzelai B. (Eds). Human and Relational Resources (pp. 44-45). the 4th International Conference on Clusters and Industrial Districts CLUSTERING, University of Valencia, Spain, May 23–24 (ISBN: 978-84-09-11926-4).
PublicationPurpose – The purpose of the paper is to explore how learning manifests and knowledge flows in cluster initiatives (CIs) due to interactions undertaken by their members. The paper addresses the research question of how social learning occurs and knowledge flows in CIs. Design/methodology/approach – The qualitative study of four cluster initiatives helped to identify various symptoms of social learning and knowledge flows in...
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A novel method of local chirp-rate estimation of LFM chirp signals in the time-frequency domain
PublicationIn the paper, novel dynamic representations of a complex signal in the time-frequency domain are introduced. The proposed approach is based on using the gradient of the short-time Fourier transform complex phase. A channelized instantaneous complex frequency (CICF) and a complex local group delay (CLGD) are included in the presented signal representations. An application of the newly-introduced distributions is demonstrated by...
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The parallel environment for endoscopic image analysis
PublicationThe jPVM-oriented environment to support high performance computing required for the Endoscopy Recommender System (ERS) is defined. SPMD model of image matching is considered and its two implementations are proposed: Lexicographical Searching Algorithm (LSA) and Gradient Serching Algorithm (GSA). Three classes of experiments are considered and the relative degree of similarity and execution time of each algorithm are analysed....
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Autonomous port management based AGV path planning and optimization via an ensemble reinforcement learning framework
PublicationThe rapid development of shipping trade pushes automated container terminals toward the direction of intelligence, safety and efficiency. In particular, the formulation of AGV scheduling tasks and the safety and stability of transportation path is an important part of port operation and management, and it is one of the basic tasks to build an intelligent port. Existing research mainly focuses on collaborative operation between...
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Fast EM-Driven Parameter Tuning of Microwave Circuits with Sparse Sensitivity Updates via Principal Directions
PublicationNumerical optimization has become more important than ever in the design of microwave components and systems, primarily as a consequence of increasing performance demands and growing complexity of the circuits. As the parameter tuning is more and more often executed using full-wave electromagnetic (EM) models, the CPU cost of the overall process tends to be excessive even for local optimization. Some ways of alleviating these issues...
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Model-free and Model-based Reinforcement Learning, the Intersection of Learning and Planning
PublicationMy doctoral dissertation is intended as the compound of four publications considering: structure and randomness in planning and reinforcement learning, continuous control with ensemble deep deterministic policy gradients, toddler-inspired active representation learning, and large-scale deep reinforcement learning costs.
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Three-dimensional mapping for data collected using variable stereo baseline
PublicationThe paper describes a system of 3D mapping of data collected with due regard for variable baseline. This solution constitute an extension to a VisRobot sub-system developed as a subsystem, necessary for implementing the generic idea of using mobile robots to explore an indoor static environment. This subsystem is to acquire stereo images, calculate the depth in the images and construct the sought 3D map. Stereo images are obtained...
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Wpływ kierunku rozchodzenia się fali detonacyjnej oraz współczynnika asymetrii na rozkład prędkości odkształceń w kotlinie walcowniczej podczas asymetrycznego walcowania pasma Al-Cu. The influences of the direction of explosion wave and asymetrical coefficient at the distribution of strain rate in the roll cap of bimetallic plate Al-Cu of rolling process.
PublicationPrzedstawiono symulacje komputerowe walcowania blach Al-Cu łączonych wybuchowo. Symulacje przeprowadzono dla procesu walcowania w walcarce o średnicy walców D=150 mm z indywidualnym napędem walców roboczych. W ramach badań numerycznych określony został wpływ kierunku rozchodzenia się fali detonacyjnej na rozkład prędkości odkształcenia w kotlinie walcowniczej asymetrycznie walcowanej blachy bimetalowej Al-Cu.
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Physics augmented classification of fNIRS signals
PublicationBackground. Predictive classification favours performance over semantics. In traditional predictive classification pipelines, feature engineering is often oblivious to the underlying phenomena. Hypothesis. In applied domains such as functional Near Infrared Spectroscopy (fNIRS), the exploitation of physical knowledge may improve the discriminative quality of our observation set. Aims. Give exemplary evidence that intervening the...
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Infrared techniques for natural convection investigations in channels between two vertical, parallel, isothermal and symmetrically heated plates
PublicationThe effect of the gap width between two symmetrically heated vertical, parallel, isothermal plates on intensity of natural convective heat transfer in a gas (Pr = 0.71) was experimentally studied using the balance and gradient methods. In the former method heat fluxes were determined based on measurements of the voltage and electric current supplying the heaters placed inside the walls. In the latter, heat fluxes were calculated...
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Maturity Mismatch in the Polish Banking System and its Impact on the Economy
PublicationIn the article maturity mismatch in the Polish banking system is estimated based on the publicly available data. Then the impact on the economy is discussed. Based on Polish central bank’s data it may be estimated that between 1996 and 2012 the maturity gap increased significantly – average residual maturity of assets exceeds 6 years in 2012 (less than 2 years in 1996), while that of liabilities remains below 1 year. The gap...
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Seawater intrusion due to pumping mitigated by natural freshwater flux: a case study in Władysławowo, northern Poland
PublicationThe paper presents a case study of seawater intrusion into a coastal aquifer, caused by a groundwater intake located close to the seashore in Władysławowo, northern Poland. Evolution of the basic hydrogeochemical parameters for the 50-year period from 1964 to 2014 indicates progressing encroachment of saline seawater into the aquifer. However, the spatial pattern of salinity was influenced by the variability of hydraulic gradient...
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Chirp-rate estimation of FM signals in the time-frequency domain
PublicationNovel dynamic representations of a complex signal in the time-frequency domain including: a channelized instantaneous complex frequency (CICF), a complex local group delay (CLGD) and a channelized instantaneous chirp-rate (CICR) are introduced. The proposed approach is based on the use of the gradient of the short-time Fourier transform complex phase. An interpretation of the newly-introduced distributions especially of the CICR...
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Sposób poprawy własności dynamicznych czujników konduktometrycznych.
PublicationW artykule przeanalizowano wpływ mechanizmu transportu migracyjnego jonów na własności dynamiczne czujników konduktometrycznych. Pokazano, że czujniki te są przetwornikami pierwszego rzędu i ich właściwości dynamiczne determinowane są przez ich budowę. Zaproponowano modyfikację konstrukcji tych czujników poprzez wprowadzenie dodatkowej elektrody polaryzacyjnej. Elektroda ta zwiększa gradient potencjału pola elektrycznego na powierzchni...
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Methods of navigation in the mobile application supporting movement of the blind
PublicationThis paper presents conclusions from the last development phase of the “Voice Maps” project. Authors specify newly found available options for navigation in affordable system for the blind with all their related aspects. System uses dedicated geographical data, built-in smartphone GPS receivers and DGPS external device in order to assist blind users in their everyday travelling. Authors also discuss new methods to improve positioning...
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Marking large amounts of student assignments
PublicationTechnologies offer plenty of possibilities to prepare individual remote online tasks for students. This gives a lot of space to search for ways to overcome the challenges, one of them being grading a high volume of student--generated content. The paper surveys the author’s experience with various forms of student e-activities and various forms of grading.
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Expedited Globalized Antenna Optimization by Principal Components and Variable-Fidelity EM Simulations: Application to Microstrip Antenna Design
PublicationParameter optimization, also referred to as design closure, is imperative in the development of modern antennas. Theoretical considerations along with rough dimension adjustment through supervised parameter sweeping can only yield initial designs that need to be further tuned to boost the antenna performance. The major challenges include handling of multi-dimensional parameter spaces while accounting for several objectives and...
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Legal and Economic Conditions of the Creating and Activity of Entrepreneursin Poland. VATT Governement Inst. Econ. Res. C**2002 [nr] 290 s. 153- 162 bibliogr. 10 poz. Discussion papers. Workshopon Studies for Nordther. Kalastajatorrpa,30-31 May 2002.Prawne i ekonomiczne uwarunkowania działalności przedsiębiorców w Polsce.
PublicationW artykule przedstawiono warunki prawne, które muszą być spełnione przyuruchamianiu działalności gospodarczej w Polsce. Wskazano również co sprzyjai co hamuje rozwój działalności przedsiębiorców w naszym kraju.
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Non linear identification of underwater vehicles. W: [CD-ROM] Conference Proceedings. The 29th Israel Conference on Mechanical Engineering. May 12-13, 2003 Haifa, Israel. Haifa: Technion - Israel Inst. Technol.**2003[B8] s. 1-8, 5 rys. bibliogr. 7 poz. Nieliniowa identyfikacja pojazdów podwodnych.
PublicationArtykuł dotyczy identyfikacji nieliniowych modeli pojazdów podwodnych o wie-lu zmiennych. Zaproponowana metoda działa w obszarze czasu rzeczywistego imoże być stosowana do nieliniowych modeli, które są liniowe w części doty-czącej nieznanego wektora parametrów. W celu poradzenia sobie z parametramizmieniającymi się w czasie, zastosowano rekursyjną wersję algorytmu identy-fikacji. Po krótkim opisie matematycznych podstaw...
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Nonlocal Vibration of Carbon/Boron-Nitride Nano-hetero-structure in Thermal and Magnetic Fields by means of Nonlinear Finite Element Method
PublicationHybrid nanotubes composed of carbon and boron-nitride nanotubes have manifested as innovative building blocks to exploit the exceptional features of both structures simultaneously. On the other hand, by mixing with other types of materials, the fabrication of relatively large nanotubes would be feasible in the case of macroscale applications. In the current article, a nonlinear finite element formulation is employed to deal with...
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GPU Acceleration of Multilevel Solvers for Analysis of Microwave Components With Finite Element Method
PublicationThe letter discusses a fast implementation of the conjugate gradient iterative method with ${rm E}$-field multilevel preconditioner applied to solving real symmetric and sparse systems obtained with vector finite element method. In order to accelerate computations, a graphics processing unit (GPU) was used and significant speed-up (2.61 fold) was achieved comparing to a central processing unit (CPU) based approach. These results...
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Modeling of active fiber Bragg grating sensors
PublicationW artykule omówiono działanie przetwornika hydrofonu wykorzystującego profilowaną membranę sprzężoną z aktywną światłowodową siatką Bragga. W wyniku modelowania, wykonanego Metodą Elementów Skończonych, stwierdzono występowanie gradientów naprężeń wzdłuż siatki. Opracowano program do modelowania pasywnych i aktywnych światłowodowych siatek Bragga wykorzystujący metodę modów sprzężonych. Przedstawiono charakterystyki widmowe pasywnych...
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A Web-GIS tool for diagnosing spatial orientation of young adults: design and evaluation of Geo-Survey
PublicationSpatial orientation is the effectiveness with which one is able to assess the mutual location of objects relative to a point of reference or a system of coordinates. Traditionally, this ability has been evaluated through field navigation tests, which do not take into account the prevailing influence of free online maps and virtual walks on a person’s interpretation of space. In this context, this study presents a Web-GIS tool designed...
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Cartographic Representation of Route Reconstruction Results in Video Surveillance System
PublicationThe video streams available in a surveillance system distributed on the wide area may be accompanied by metadata are obtained as a result of video processing. Many algorithms applied to surveillance systems, e.g. event detection or object tracking, are strictly connected with localization of the object and reconstruction of its route. Drawing related information on a plan of a building or on a map of the city can facilitate the...
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Machine learning-based seismic fragility and seismic vulnerability assessment of reinforced concrete structures
PublicationMany studies have been performed to put quantifying uncertainties into the seismic risk assessment of reinforced concrete (RC) buildings. This paper provides a risk-assessment support tool for purpose of retrofitting and potential design strategies of RC buildings. Machine Learning (ML) algorithms were developed in Python software by innovative methods of hyperparameter optimization, such as halving search, grid search, random...
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ATTEMPTS OF THERMAL IMAGING CAMERA USAGE IN ESTIMATIONS OF THE CONVECTIVE HEAT LOSS FROM A VERTICAL PLATE
PublicationIn this paper a new method for determining heat transfer coefficients using a gradient method has been developed. To verify accuracy of the proposed method vertical isothermal heating plate with natural convection mechanism has been examined. This configuration was deliberately chosen, because of the fact that such case is historically the earliest and most thoroughly studied and its rich scientific documentation - the most reliable....
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Development of advanced machine learning for prognostic analysis of drying parameters for banana slices using indirect solar dryer
PublicationIn this study, eXtreme Gradient Boosting (XGBoost) and Light Gradient Boosting (LightGBM) algorithms were used to model-predict the drying characteristics of banana slices with an indirect solar drier. The relationships between independent variables (temperature, moisture, product type, water flow rate, and mass of product) and dependent variables (energy consumption and size reduction) were established. For energy consumption,...
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100– lecie urodzin profesora Romualda Kolmana 1922-2016, patrona Konkursu IKAR JAKOŚCI. Kamienie milowe w dorobku twórcy kwalitologii w Polsce
Publication17 czerwca 2022 roku minęła 100. rocznica urodzin śp. profesora dr. hab. inż. Romualda Kolmana, jednego z najczęściej przywoływanych twórców i krzewicieli Polskiej Szkoły Jakości. Jako podwładny i doktorant profesora w ostatnim, przypadającym na lata 90. XX wieku okresie jego pracy na Wydziale Mechanicznym Technologicznym w Politechnice Gdańskiej, miałem tę możliwość i szczęście, że mogłem zapoznać się z praktycznie całym dorobkiem...
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Dual-band antenna with improved gain for WLAN and ISM applications
PublicationIn this Letter, a dual-band antenna with an improved gain is proposed. The structure features 9.7 and 10.4 dBi gain within 2.4 GHz to 2.5 GHz and 5 GHz to 6 GHz bands, respectively. This makes it suitable for WLAN and ISM applications. The structure comprises an asymmetrical pair of radiators and slots suspended over a reflector. The antenna is optimised in a two-stage process using a trust-region-based gradient search algorithm....
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The cohomological span of LS-Conley index
PublicationIn this paper we introduce a new homotopy invariant – the cohomological span of LS-Conley index. We prove the theorems on the existence of critical points for a class of strongly indefinite functionals with the gradient of the form Lx+K(x), where L is bounded linear and K is completely continuous. We give examples of Hamiltonian systems for which our methods give better results than the Morse inequalities. We also give a formula...
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A Review of Reduction Methods of Impact of Common-Mode Voltage on Electric Drives.
PublicationIn this survey paper, typical solutions that focus on the reduction in negative effects resulting from the common-mode voltage influence in AC motor drive applications are re-examined. The critical effectiveness evaluation of the considered methods is based on experimental results of tests performed in a laboratory setup with an induction machine fed by an inverter. The capacity of a common-mode voltage level reduction and voltage...
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UDP-glukuronylotransferazy - białka siateczki śródplazmatycznej. Struktura i mechanizm działania
PublicationIzoenzymy UDP-glukuronylotransferazy (EC. 2.4.1.17), UGT, katalizują w organizmach ssaków reakcję koniugacji grupy glikozylowej pochodzącej z nukleotydu UDPGA z aglikonem. UDPGA jest przyłączany do odpowiedniej grupy funkcyjnej metabolitu I fazy, rzadziej związku wyjściowego, przez co polarność aglikonu i zdolność jego wydalania z komórki zwiększa się, a to w konsekwencji obniża efekt toksyczny.Struktura UGT zawiera 2 domeny. Domena...