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Search results for: system loss model
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Design of experiments approach for ultimate strength assessment of corroded stiffened plates
PublicationThe impact of corrosion degradation on the ultimate strength of stiffened plates subjected to compressive loading is investigated. The DoE technique is used considering different plate and column slenderness ratios and corrosion severity. The FE method, considering geometrical and material nonlinearities, is employed. A two-stage corrosion degradation model is adopted. Firstly, a uniform thickness loss is adopted to reflect the...
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A structure and simulation-driven design of compact CPW-fed UWB antenna
PublicationIn this letter, a structure of a miniaturized ultra-wideband CPW-fed antenna and its design proce-dure are presented. The antenna is a modified version of the design previously proposed in the literature, with additional degrees of freedom introduced in order to improve the structure flexibility. The small size is achieved by executing a rigorous optimization procedure that consists of two stages: (i) smart random search carried...
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Three-Dimensional Printing of Bone Models
PublicationThe trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of...
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A Computationally Efficient Model for Predicting Successful Memory Encoding Using Machine-Learning-based EEG Channel Selection
PublicationComputational cost is an important consideration for memory encoding prediction models that use data from dozens of implanted electrodes. We propose a method to reduce computational expense by selecting a subset of all the electrodes to build the prediction model. The electrodes were selected based on their likelihood of measuring brain activity useful for predicting memory encoding better than chance (in terms of AUC). A logistic...
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The field–dependent interface recombination velocity for organic–inorganic heterojunction
PublicationWe have derived an analytical formula which describes the field–dependent interface recombination velocity for the boundary of two materials characterized by different permittivities. The interface recombination of charge carriers has been considered in the presence of image force Schottky barrier. We suggest that this effect may play an important role in the loss of current for organic–inorganic hybrid heterojunctions. It has...
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Acoustics - new services for urban planning, research and education
PublicationThe main purpose of the presented design is twofold, namely: providing detailed information about the noise threats that occur every day in city areas and preventing the noise induced hearing loss especially among young people. An experimental system designed for the continuous monitoring of the acoustic climate of urban areas was developed and implemented within the PLGrid Plus project. The assessment of environmental threats...
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The photocurrent quantum efficiency dependence on the applied voltage in organic solar cells
PublicationWe demonstrate that our recently reported model (Szmytkowski 2007 J. Phys. D: Appl. Phys. 40 3352) of the photocurrent quantum efficiency in organic semiconductors explains the external quantum efficiency dependence on the electric field in organic solar cells. This effect can be explained by taking into account that the photogeneration of charge carriers occurs via the electron-hole pair dissociation and the space charge effects...
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Badania stanu technicznego ścianek szczelnych strony południowej i północnej komory południowej śluzy Dzierżno
PublicationPrace dotyczyły badań nieniszczących łączników (zamków) Paine`a oraz ścianek szczelnych. Ściany boczne komory południowej śluzy Dzierżno zbudowane są ze stalowych pasów blachy o grubości około 16mm i długości 22m połączonych ze sobą wzdłuż dłuższej krawędzi za pomocą zamków Peine`a. System ten umożliwia uzyskanie szczelnego połączenia na całej długości ścianki. Zaawansowany proces korozji spowodował rozszczelnienie połączenia...
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Kontekstowo zorientowany model bezpieczeństwa systemów internetowych
PublicationW rozprawie dokonano analizy usługowych systemów internetowych pod względem bezpieczeństwa. Przedstawiono autorskie uniwersalne modele bezpieczeństwa CoRBAC oraz jego rozszerzenie TCoRBAC, będące rozwinięciem tradycyjnego modelu RBAC. Uwzględniono analizę szeroko rozumianego kontekstu funkcjonowania systemu oraz poziom jego zaufania do użytkownika. Opracowano metodę wyznaczania dwóch parametrów: zaufania do systemu (λ) będącego...
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Deep Learning Optimization for Edge Devices: Analysis of Training Quantization Parameters
PublicationThis paper focuses on convolution neural network quantization problem. The quantization has a distinct stage of data conversion from floating-point into integer-point numbers. In general, the process of quantization is associated with the reduction of the matrix dimension via limited precision of the numbers. However, the training and inference stages of deep learning neural network are limited by the space of the memory and a...
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Radio Channel Measurements in 868 MHz Off-Body Communications in a Ferry Environment
PublicationIn this paper, a characterization of the 868 MHz off-body radio channel in BANs is presented. Measurements were carried out in a ferry environment using a specific set-up. A method for path loss using radio distance measurements (RDMs) was developed. It allows to automate the measurements process and make it independent from the variable speed of a moving person. Based on the observed path loss as a function of distance, the obtained...
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Ellipticity of gradient poroelasticity
PublicationWe discuss the ellipticity properties of an enhanced model of poroelastic continua called dilatational strain gradient elasticity. Within the theory there exists a deformation energy density given as a function of strains and gradient of dilatation. We show that the equilibrium equations are elliptic in the sense of Douglis–Nirenberg. These conditions are more general than the ordinary and strong ellipticity but keep almost all...
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Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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Measurement Stand and Methodology for Research of the Off-Body and Body-to-Body Radio Channels in WBANs with Different Diversity Schemes
PublicationThe concept of an experimental test bed for system loss and channel impulse response measurements for off-body and body-to-body radio channels in wireless body area networks (WBANs) is fully described. The possible measurement scenarios that may occur in investigation of off-body and body-to-body channels are classified and described in detail. Additionally, an evaluation is provided of the standard and expanded uncertainties of...
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Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation
PublicationThe transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering...
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The use of Response Surface Methodology for reliability estimation of aluminum silo subjected to wind load
PublicationAn axisymmetric aluminum silo model with a single, standardized geometric imperfection of its lateral surface is considered. The silo is wind – loaded only. The paper is focused on the critical, or limit value of wind pressure, both producing a loss of stability of the silo. This value is affected by vertical coordinate (position) of the imperfection and the angular relation between the imperfection and the wind direction. Reliability...
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Rotor Blade Geometry Optimisation in Kaplan Turbine
PublicationThe paper presents the description of method and results of rotor blade shape optimisation. The rotor blading constitutes a part ofturbine flow path. Optimisation consists in selection of the shape that minimises ratio of polytrophic loss. Shape of the blade isdefined by the mean camber line and thickness of the airfoil. Thickness is distributed around the camber line based on the ratio ofdistribution. Global optimisation was done...
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System oceny efektywności użytkowania aparatów słuchowych (Hearing aid use effectiveness evaluation system)
PublicationCelem rozprawy jest opracowanie metody oceny efektywności protezowania słuchu przy użyciu aparatów słuchowych, która pozwoli w łatwy sposób poddawać ocenie korzyść z użytkowania protez słuchowych w najbardziej typowych sytuacjach akustycznych. Przedstawiono genezę podjętych badań i na tej podstawie zaproponowano cele i tezy rozprawy doktorskiej. W pracy w pierwszej kolejności zawarto przegląd dotyczący rodzajów ubytku słuchu...
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublicationConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
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Thermodynamic analysis of the Compressed Air Energy Storage system coupled with the Underground Thermal Energy Storage
PublicationImprovement of flexibility is one of the key challenges for the transformation of the Polish Power System aiming at a high share of renewable energy in electricity generation. Flexible and dispatchable power plants will contribute to this ongoing transformation process as they compensate for fluctuations in electricity generation from renewable energy sources such as wind and photovoltaics. In this context, CAES storage tanks are...
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Physics-guided neural networks (PGNNs) to solve differential equations for spatial analysis
PublicationNumerous examples of physically unjustified neural networks, despite satisfactory performance, generate contradictions with logic and lead to many inaccuracies in the final applications. One of the methods to justify the typical black-box model already at the training stage and lead to many inaccuracies in the final applications. One of the methods to justify the typical black-box model already at the training stage involves extending...
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GPU Power Capping for Energy-Performance Trade-Offs in Training of Deep Convolutional Neural Networks for Image Recognition
PublicationIn the paper we present performance-energy trade-off investigation of training Deep Convolutional Neural Networks for image recognition. Several representative and widely adopted network models, such as Alexnet, VGG-19, Inception V3, Inception V4, Resnet50 and Resnet152 were tested using systems with Nvidia Quadro RTX 6000 as well as Nvidia V100 GPUs. Using GPU power capping we found other than default configurations minimizing...
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An automated learning model for twitter sentiment analysis using Ranger AdaBelief optimizer based Bidirectional Long Short Term Memory
PublicationSentiment analysis is an automated approach which is utilized in process of analysing textual data to describe public opinion. The sentiment analysis has major role in creating impact in the day-to-day life of individuals. However, a precise interpretation of text still relies as a major concern in classifying sentiment. So, this research introduced Bidirectional Long Short Term Memory with Ranger AdaBelief Optimizer (Bi-LSTM RAO)...
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Robert Małkowski dr hab. inż.
People -
Fault-tolerant performance of the novel five-phase doubly-fed induction generator
PublicationThe article presents the concept of a new design of a multi-phase doubly-fed induction generator (DFIG). The innovative design approach uses a five-phase power supply from the rotor side of the generator with a three-phase classic stator power supply. Modern three-phase doubly-fed induction generators are the dominant choice for Wind Energy Conversion Systems (WECS). Solutions of this type are sensitive to the loss of at least...
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Application of Doubly Connected Dominating Sets to Safe Rectangular Smart Grids
PublicationSmart grids, together with the Internet of Things, are considered to be the future of the electric energy world. This is possible through a two-way communication between nodes of the grids and computer processing. It is necessary that the communication is easy and safe, and the distance between a point of demand and supply is short, to reduce the electricity loss. All these requirements should be met at the lowest possible cost....
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Impact of the glazed roof on acoustics of historic interiors
PublicationThe paper discusses the adverse acoustic phenomena occurring in the semi-open interiors (courtyards, yards) covered with a glass roof. Particularly negative is the rever-beration noise, which leads to the degradation of the utility functions of the resulting spaces. It involves the drastically reducing the intelligibility of speech, loss of natural sounding of music, problems with the sound system, as well as disturbances in the...
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Intra-subject class-incremental deep learning approach for EEG-based imagined speech recognition
PublicationBrain–computer interfaces (BCIs) aim to decode brain signals and transform them into commands for device operation. The present study aimed to decode the brain activity during imagined speech. The BCI must identify imagined words within a given vocabulary and thus perform the requested action. A possible scenario when using this approach is the gradual addition of new words to the vocabulary using incremental learning methods....
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Semantic Driven Table Understanding in Born-Digital Documents
PublicationThis paper presents a new approach to table understanding, suitable for born-digital PDF documents. Advance beyond the current state of the art in table understanding is provided by the proposed reverse MVC method, which takes advantage of only partial logic structure loss (degradation) in born-digital PDF documents, as opposed to unrecoverable loss (deterioration) taking place in scan based PDF documents.
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Cognitive memory for intelligent systems of decision-making, based on human psychology
PublicationA model of memory, which allows to expand the functionality of autonomous decision-making systems for robotic and human-system-interface purposes, is discussed. The model provides functions and features which make the prospective robotic and interfacing systems more human-like as well as more efficient in solving interactive issues.
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Identification of damages in the inlet air duct of a diesel engine based on exhaust gas temperature measurements
PublicationThe temperature of the exhaust gas of a diesel piston engine, measured in the characteristic control sections of its thermo-flow system, can be a valuable source of diagnostic information about the technical condition of the elements limiting the working spaces thus separated, including the turbocharging system, but also its fuel supply system and replacement of the medium. In standard marine engine measurement systems equipped...
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Low energy electron mass stopping power in H2
PublicationWe present experimental mass stopping powers of electrons in gaseous H2 obtained with a newly developed electron time-of-flight spectrometer, for the incident electron energy range of 10eV to 25eV. In our procedure the average energy loss is derived from our conversion of measured electron time-of-flight spectra into equivalent electron energy loss spectra so as to obtain the values of mass stopping power for electron scattering...
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INFLUENCE OF TEMPERATURE ON THE ACTIVITY OF ANAMMOX GRANULAR BIOMASS - SHORT AND LONG-TERM ASPECT
PublicationThe aim of this study was to determine a short-term and long-term effect of temperature on the anammox process rate and determination of temperature coefficients in the Arrhenius and Ratkowski equations. The short-term effects of temperature on the anammox biomass were investigated in batch tests at ten different temperatures in the range of 10-55 ̊C. The maximum rate 1.3 gN (gVSS·d)-1 observed at 40 ̊C. The minimum rate, close...
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Analytical Estimation of Power Losses in a Dual Active Bridge Converter Controlled with a Single-Phase Shift Switching Scheme
PublicationMicro-grid solutions around the world rely on the operation of DC/DC power conver- sion systems. The most commonly used solution for these topologies is the use of a dual active bridge (DAB) converter. Increasing the efficiency and reliability of this system contributes to the improvement in the stability of the entire microgrid. This paper discussed an analytical method of energy efficiency and power loss estimation in a single...
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Guido: a musical score recognition system
PublicationThis paper presents an optical music recognition system Guido that can automatically recognize the main musical symbols of music scores that were scanned or taken by a digital camera. The application is based on object model of musical notation and uses linguistic approach for symbol interpretation and error correction. The system offers musical editor with a partially automatic error correction.
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System information propagation for composite structures
PublicationWe study in details decoherence process of a spin register, coupled to a spin environment. We use recently developed methods of information transfer study in open quantum systems to analyze information flow between the register and its environment. We show that there are regimes when not only the register decoheres effectively to a classical bit string, but this bit string is redundantly encoded in the environment, making it available...
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Pipeline geometry defects in high resolution pig's data
PublicationMost of the pipelines have been inspected at least once using intelligent pigging. The problem of specific software for interactive presentation, analysis and comparison of features revealed during the consecutive geometry surveys is emphasized. Capabilities of a simultaneous measurement of internal geometry and metal loss features in a single run are illustrated. Advantages of application of statistical characteristics of both...
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Metoda TrustCritic oceny wiarygodności sklepów internetowych
PublicationW artykule przedstawiono metodę oceny wiarygodności sklepów internetowych TrustCritic. Powszechnie występujące nadużycia w handlu elektronicznym sprawiają, że zaufanie do przedsiębiorcy staje się kluczowym czynnikiem decyzji konsumentów. Przedsiębiorca narażony jest na niezgodność z prawem, utratę wizerunku i klientów. Artykuł omawia problematykę nadużyć w sferze e-biznesu oraz proponuje wielokryterialny model oceny sklepu internetowego,...
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Laxer Clinical Criteria for Gaming Disorder May Hinder Future Efforts to Devise an Efficient Diagnostic Approach: A Tree-Based Model Study
PublicationInternet Gaming Disorder (IGD) has been recognized in May 2013 and can be evaluated using the criteria developed by American Psychiatric Association (APA). The present study investigated the role each IGD criteria plays in diagnosing disordered gaming. A total of 3,377 participants (mean age 20 years, SD = 4.3 years) participated in the study. The data collected was scrutinized to detect patterns...
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Efficiency limit of excitonic photovoltaic cells under phosphor-based white LED illumination
PublicationThe limit of energy conversion of excitonic photovoltaic cells working under white light illumination generated by phosphor-based LED is analysed using the modified Giebink approach. Particularly, the impact of the optical energy gap and energy loss associated with the excitons dissociation at the heterojunction interface on power conversion efficiency of the device are discussed. From the results of our study it follows that the...
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CMGNet: Context-aware middle-layer guidance network for salient object detection
PublicationSalient object detection (SOD) is a critical task in computer vision that involves accurately identifying and segmenting visually significant objects in an image. To address the challenges of gridding issues and feature...
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TG-hydroxyl groups in TiO2-P25
Open Research DataTG analyses were performed for powdered TiO2 - commercial P25 sample, which was heat-treated from room temperature to 500 C in the nitrogen atmosphere. Mass loss at lower temperature such as 120 C was related to the physisorbed water, and that one occurring at 500 C to the chemisorbed hydroxyl groups.
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Basic financial categories of non-public universities in 2010 (in PLN thousand)
Open Research DataIn 2010, non-public universities achieved a positive gross and net financial result. In nominal terms, the net financial result decreased compared to 2009 by 43.7%. It was lower than the net financial result of public universities by PLN 348.3 million. and amounted to PLN 148.1 million.
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Experimental determination of H2 mass stopping powers for low-energy electrons
PublicationWe present experimental mass stopping powers of electrons in gaseous H2 obtained with an electron time- of-flight spectrometer, for the incident electron energy range of 11 to 25 eV. In our procedure, the average energy loss is derived from conversion of the measured electron time-of-flight spectra into equivalent electron energy-loss spectra. Our present results are compared with the only available experimental measurement and...
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A Method for Optimising the Blade Profile in Kaplan Turbine
PublicationThis paper introduces a method of blade profile optimisation for Kaplan-type turbines, based on modelling the interaction between rotor and stator blades. Rotor and stator blade geometry is described mathematically by means of a midline curve and thickness distribution. Genetic algorithms are then used to find a global optimum that minimises the loss coefficient. This allows for variety of possible blade shapes and configurations....
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On the approximation of the UWB dipole elliptical arms with stepped-edge polygon
PublicationA simple method of approximation of the ellipticalpatch with stepped-edge polygon is proposed as an introductionto wider studies over the planar ultrawideband (UWB) antennas.The general idea is to replace the elliptical patch with an equivalentpolygonal patch, with minimum loss in the performance. Theprinciples of the proposed method are presented in this letter, aswell as the results of performed numerical studies and its experimentalverification....
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Spirometry measurement model - the diagnostic purpose support
Publicationthe paper presents a new model of respiratory mechanism based on the spirometry measurements. the spirometry test assesses the efficiency of the lung ventilation. the respiratory system functioning is based on the ventilation mechanism. thus the quality of the lung depends on the quality of lung ventilation. modelling of the respiratory system supports a diagnostic process. the model parameter estimates are obtained on the basis...
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A repeated game formulation of network embedded coding for multicast resilience in extreme conditions
PublicationComputer networks and data sharing applications are vital for our current society and fundamental for any available ICT solution, so that networking is considered as one of the key critical infrastructures and its correct behavior should be always enforced, even in case of disasters or severe execution conditions. Resilience is a strongly demanding nonfunctional requirement for current computer networks, and one of the key factors...
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Acute myocardial infarction - Male, 71 - Tissue image [12030630017643841]
Open Research DataThis is the histopathological image of HEART, MEDIASTINUM, AND PLEURA tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Acute myocardial infarction - Male, 71 - Tissue image [12030630017642361]
Open Research DataThis is the histopathological image of HEART, MEDIASTINUM, AND PLEURA tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.