Filters
total: 5596
-
Catalog
displaying 1000 best results Help
Search results for: STATISTICAL SIZE EFFECT
-
ENERGY ANALYSIS OF PROPULSION SHAFT FATIGUE PROCESS IN ROTATING MECHANICAL SYSTEM PART I TESTING SIGNIFICANCE OF INFLUENCE OF SHAFT MATERIAL FATIGUE EXCITATION PARAMETERS
PublicationThe article discusses the problem of mathematical modelling of energy conversion processes in a rotating mechanical system for the purpose of identifying fatigue states of propulsion shafts in this system. A simplified physical model of the analysed system, constructed in an appropriate scale, has made the basis for the experimental research. The research programme took into consideration mechanical fatigue excitation of the model...
-
Statistical Data Pre-Processing and Time Series Incorporation for High-Efficacy Calibration of Low-Cost NO2 Sensor Using Machine Learning
PublicationAir pollution stands as a significant modern-day challenge impacting life quality, the environment, and the economy. It comprises various pollutants like gases, particulate matter, biological molecules, and more, stemming from sources such as vehicle emissions, industrial operations, agriculture, and natural events. Nitrogen dioxide (NO2), among these harmful gases, is notably prevalent in densely populated urban regions. Given...
-
Motives for Going International and Entry Modes of Family Firms in Poland
PublicationThe artucule in the theoretical part focuses on theoretical concepts of firm internationalisation and specifics of internationalisation of FBs, especially their motives for going international. In the empirical part the quqantitative approach is adopted. The results of survey are presented on the sample of 216 firms, including 88 FBs. The statistical analysis is carried out
-
Controlling computer by lip gestures employing neural network
PublicationResults of experiments regarding lip gesture recognition with an artificial neural network are discussed. The neural network module forms the core element of a multimodal human-computer interface called LipMouse. This solution allows a user to work on a computer using lip movements and gestures. A user face is detected in a video stream from a standard web camera using a cascade of boosted classifiers working with Haar-like features....
-
Analiza wyników monitoringu odbieraków prądu w warunkach ruchowych na linii kolejowej
PublicationOmówiono metodę ciągłego monitorowania stanu odbieraków prądu na linii kolejowej w oparciu o pomiar uniesienia przewodów jezdnych sieci trakcyjnej w czasie przejazdu pociągu. Omówiono zasadę działania wdrożonego stanowiska monitoringu. Opisano algorytmy analizy danych pomiarowych - w szczególności oszacowania siły statycznej odbieraka prądu - i przyjęte kryteria oceny odbieraka. W analizie bierze się pod uwagę także prędkość pociągu...
-
Ekonometryczna analiza konsumpcji w Polsce w latach 1995-2018- statyczne modele wydatków konsumpcyjnych w wartościach nominalnych
PublicationW artykule przeprowadzono badania makroekonomicznych związków pomiędzy konsumpcją globalną (C) a produktem krajowym brutto (PKB). W części teoretycznej artykułu: • zdefiniowano postacie analityczne przyczynowo-skutkowych makromodeli konsumpcji, • sformułowano interpretację mierników opisujących badane zależności, • sformułowano założenia stochastyczne dla rozważanych makromodeli konsumpcji, W części empirycznej artykułu:...
-
A multi‑criteria approach to investigate spatial distribution,sources, and the potential toxicological effect of polycyclic aromatic hydrocarbons (PAHs) in sediments of urban retention tanks
PublicationBottom sediments deposited in retention tanks (RTs) located on two urban streams (Oliwski and Strzyza) in the central part of Gdansk (Poland) were analysed for polycyclic aromatic hydrocarbons’ (PAHs) content. PAHs were extracted from samples with methylene chloride, then the extracts were subjected to clean-up applying the solid phase extraction (SPE) method. Quantitative and qualitative determination of 16 PAHs was performed...
-
Analyzing Wind Energy Potential Using Efficient Global Optimization: A Case Study for the City Gdańsk in Poland
PublicationWind energy (WE), which is one of the renewable energy (RE) sources for generating electricity, has been making a significant contribution to obtaining clean and green energy in recent years. Fitting an appropriate statistical distribution to the wind speed (WS) data is crucial in analyzing and estimating WE potential. Once the best suitable statistical distribution for WS data is determined, WE potential and potential yield could...
-
Evaluation of possibilities of genotyping of Candida glabrata clinical isolates with RAPD-PCR method and microsatellite analysis
PublicationThe aim of the study was to compare the discriminatory power of RAPD-PCR method using RSD10 primer and microsatellite (GACA)4 analysis for genotyping clinical isolates of C. glabrata. Isolates were received from patients of two Polish hospitals: Children's Memorial Health Institute in Warsaw (n=17) and Medical University of Gdansk (n=37). Species identification was confirmed by two phenotypic methods: growth on chromagar plates...
-
Computer-Aided Detection of Hypertensive Retinopathy Using Depth-Wise Separable CNN
PublicationHypertensive retinopathy (HR) is a retinal disorder, linked to high blood pressure. The incidence of HR-eye illness is directly related to the severity and duration of hypertension. It is critical to identify and analyze HR at an early stage to avoid blindness. There are presently only a few computer-aided systems (CADx) designed to recognize HR. Instead, those systems concentrated on collecting features from many retinopathy-related...
-
One Year Evaluation of Material Properties Changes of Polylactide Parts in Various Hydrolytic Degradation Conditions
PublicationBiodegradable biocompatible materials are widely used in medical applications. Determining the possibility of using biodegradable materials depends on determining the changes in their parameters over time due to degradation. The current scientific research on biodegradable materials has presented results based on research methods characterized by the different geometry and cross-section size of the specimen, type of degradation...
-
Charge dependence of fragmentation process induced by ion collisions with furan molecule
PublicationThe goal of this work is to describe the system evolution after ion-molecule interaction. We combine different quantum chemistry and statistical mechanics approaches in order to give extended description of the process. Herein we report on a recent study of the fragmentation mechanism of neutral, singly- and doubly-ionized furan molecule in the gas phase.
-
Measurements of Path Loss in Off-Body Channels in Indoor Environments
PublicationThis paper presents a measurements of the path loss for validation of a statistical model for off-body radio channels in an indoor multipath environment, which considers the distance dependent mean path loss, and describes body shadowing and fast fading components in a statistical way. The measurement equipment and propagation indoor environment have been presented. Two different bodies and five static and two walking scenarios...
-
On Some Aspects of Fish Target Strength Estimation in Shallow Waters
PublicationThe theory of acoustic surveys for determining fish abundance are well established in fishery acoustics. The origins of the estimation are related to overcoming the problem of unknown position of target in the beam using statistical inversion. Although recently researchers use more sophisticated echosounders that provides more informative data allowing for direct solution it is known that the results are biased due to not ideally...
-
Chemometric Evaluation of WWTPs’ Wastewaters and Receiving Surface Waters in Bulgaria
PublicationWastewater treatment plant (WWTP) installations are designed and operated to reduce the quantity of pollutants emitted to surface waters receiving treated wastewaters. In this work, we used classical instrumental studies (to determine chemicals and parameters under obligations put with Directive 91/271/EEC), ecotoxicological tools (Sinapis alba root growth inhibition (SA-RG) and Heterocypris incongruens mortality (MORT) and growth...
-
Global and regional economic inequality: Methods of measurement and evidences
PublicationThe lack of countries’ statistical income data, comparable across countries and years, seems to be the main reason of controversial conjectures concerning global inequality and its evolution over time. In the databases, which purport to collect income data on a worldwide scale, only some summary statistics (quantile income shares, means, Gini indices) are presented. Therefore, the development of efficient methods of extracting...
-
Thermodynamics and statistical physics - 2023
e-Learning Courses -
Thermodynamics and statistical physics -2024
e-Learning Courses -
Wzrost gospodarczy a zapotrzebowanie na prace - teoria i rzeczywistość gospodarcza Polski w latach 1995-2014
PublicationW części teoretycznej artykułu w pierwszej kolejności przedstawiono makroekonomiczne podstawy zapotrzebowania na pracę w warunkach postępu technicznego oraz zmian kapitału rzeczowego. W następnej kolejności sformułowano założenia dla modelu opisującego zależności pomiędzy stopami wzrostu produktu krajowego i zatrudnienia. W części empirycznej artykułu rozważano wybrane wersje oszacowanego modelu opisujące gospodarkę Polski. Do...
-
SUBJECTIVE PERCEPTION OF MUSIC GENRES IN THE FIELD OF MUSIC INFORMATION RETRIEVAL SYSTEMS
PublicationThe aim of this paper is to evaluate the relationship between perception of music genres and subjective features of music that can be assigned to them. For this purpose a group of subjective features such as loudness, melody, rhythm, volume, instrumentation was chosen to describe music genres. A group of 30 listeners with normal hearing, ranging from 20 to 40, was created. Each sub-ject participating in listening tests was asked...
-
SUBJECTIVE PERCEPTION OF MUSIC GENRES IN THE FIELD OF MUSIC INFORMATION RETRIEVAL SYSTEMS
PublicationThe aim of this paper is to evaluate the relationship between perception of music genres and subjective features of music that can be assigned to them. For this purpose a group of subjective features such as loudness, melody, rhythm, volume, instrumentation was chosen to describe music genres. A group of 30 listeners with normal hearing, ranging from 20 to 40, was created. Each sub-ject participating in listening tests was asked...
-
Adaptive Method for Modeling of Temporal Dependencies between Fields of Vision in Multi-Camera Surveillance Systems
PublicationA method of modeling the time of object transition between given pairs of cameras based on the Gaussian Mixture Model (GMM) is proposed in this article. Temporal dependencies modeling is a part of object re-identification based on the multi-camera experimental framework. The previously utilized Expectation-Maximization (EM) approach, requiring setting the number of mixtures arbitrarily as an input parameter, was extended with the...
-
Fading Modeling in Maritime Container Terminal Environments
PublicationIn this paper, an analytical model for slow and fast fading effects in maritime container terminals is derived, from fitting distributions to the results of measurements performed in an actual operational environment. The proposed model is composed of a set of equations, enabling to evaluate fading statistical distribution parameters for different system and environments conditions, as a function of frequency, base station antenna...
-
Novel analytical method for detection of orange juice adulteration based on ultra-fast gas chromatography
PublicationThe food authenticity assessment is an increasingly important issue in food quality and safety. The application of an electronic nose based on ultra-fast gas chromatography technique enables rapid analysis of the volatile compounds from food samples. Due to the fact that this technique provides chemical profiling of natural products, it can be a powerful tool for authentication in combination with chemometrics. In this article,...
-
UNDECLARED WORK IN POLAND CHARACTERISTICS AND PREVALENCE
PublicationThis article aims to present the significance and prevalence of the phenomenon of undeclared work. First, we discuss the definitional issues of this phenomenon. Then, we present previous estimates on shadow economy and undeclared work in Poland, based on statistics provided by Central Statistical Office and other research entities. Our analysis covers the years 2000–2014. In the last part of the article, we use data from the Labour...
-
Fluctuation-Enhanced Sensing
PublicationFluctuation-enhanced sensing (FES) is an exciting and relatively new research field that promises to extend the range of information that can be extracted from a single sensor. In FES, the stochastic fluctuations of the sensor signal, rather than its average value, are recorded and analyzed. Typical components of such fluctuations are due to interactions at the microscopic level. Proper statistical analysis provides optimum sensory...
-
Analysis of antibiotic resistance in Escherichia coli isolated from the Reda River and the Oliwski Stream using basic statistical methods = Zastosowanie metod ststystycznych do analizy antybiotykoodporności bakterii wskaźnikowych pochodzących z rzeki Redy i Potoku Oliwskiego
PublicationIn this study distribution of antimicrobial resistance patterns among fecal indicator bacteria (Escherichia coli and Enterococcus spp.) was examined in two watercourses. The susceptibility analyses were carried out against the antimicrobial agents, important in treating human E. coli and enterococcal infection. Water samples were obtained from the Oliwski Stream and from the Reda River. On each watercourse the five representative...
-
The effect of anthropogenic activity on BTEX, NO2, SO2, and CO concentrations in urban air of the spa city of Sopot and medium-industrialized city of Tczew located in North Poland
PublicationThe major goal of the present study is to compare the air quality of two urban locations situated in Northern Poland – the spa City of Sopot and the medium-industrialized city of Tczew using chemometric methods. As a criterion for the assessment of atmospheric air quality, measurements of benzene, toluene, ethylbenzene and total xylenes were used (collected from atmospheric air using diffusion-type passive samplers) as well as...
-
An Empirical Propagation Model for Corridors in Office Buildings
PublicationThis paper presents an empirical propagation path loss model for corridors in office buildings. The proposed model estimates changeable character of radio signal attenuation, based on a special approach as a combination of the simple free-space model with the author’s model. The measurement stand and measurement scenario are described. The propagation path loss research have been made in corridor for different frequencies in range...
-
Activation Energy and Inclination Magnetic Dipole Influences on Carreau Nanofluid Flowing via Cylindrical Channel with an Infinite Shearing Rate
PublicationThe infinite shear viscosity model of Carreau fluid characterizes the attitude of fluid flow at a very high/very low shear rate. This model has the capacity for interpretation of fluid at both extreme levels, and an inclined magnetic dipole in fluid mechanics has its valuable applications such as magnetic drug engineering, cold treatments to destroy tumors, drug targeting, bio preservation, cryosurgery, astrophysics, reaction kinetics,...
-
Phase Transition in a Sequence-Structure Channel
PublicationWe study an interesting channel which maps binary sequences to self-avoiding walks in the two-dimensional grid, inspired by a model of protein folding from statistical physics. The channel is characterized by a Boltzmann/Gibbs distribution with a free parameter corresponding to temperature. We estimate the conditional entropy between the input sequence and the output fold, giving an upper bound which exhibits an unusual phase transition...
-
Empirical Adjustment of the Selected Propagation Models for Application in the Peculiar Environment of the Container Terminal
PublicationIt is important to look for any propagation model that could be useful for designing mobile radio systems in container terminal environment. Selected propagation models have been investigated. The applied research methodology has been described too. Results of the statistical adjustment in terms of signal loss determination in such environment have been analysed. The analysis has proved effectiveness of adjustment by increasing...
-
Selected Propagation Models Modification for Application in Container Terminal
PublicationIt is particularly important to look for any propagation model that could be useful for designing mobile radio systems in container terminal environment. The selected propagation models have been investigated. The applied research methodology has been described too. Results of the statistical adjustment in terms of signal loss determination in such environment have been analysed. The analysis have proved effectiveness of adjustment...
-
The Verification of the Usefulness of Electronic Nose Based on Ultra-Fast Gas Chromatography and Four Different Chemometric Methods for Rapid Analysis of Spirit Beverages
PublicationSpirit beverages are a diverse group of foodstuffs. They are very often counterfeited which cause the appearance of low quality products or wrongly labelled products on the market. It is important to find a proper quality control and botanical origin method enabling the same time preliminary check of the composition of investigated samples, which was the main goal of this work. For this purpose, the usefulness of electronic nose...
-
Sczepność międzywarstwowa w nowobudowanych nawierzchniach w Polsce
PublicationW artykule przedstawiono analizę wyników badań sczepności międzywarstwowej warstw asfaltowych przeprowadzonych na podstawie danych z monitoringu właściwości fizyko-mechanicznych warstw asfaltowych z lat 2012-2013. Monitoring prowadziły Laboratoria Drogowe oddziałów GDDKiA w ramach własnych badań kontrolnych podczas realizowanych inwestycji. Analizie poddano 7043 wyników badań sczepności międzywarstwowej badanych próbek, odwierconych...
-
Rola inicjatyw społecznych w ochronie dziedzictwa kulturowego na przykładzie mozaiki Anny Fiszer na ścianie kina Neptun w Gdańsku
PublicationStreszczenie: Rola inicjatyw społecznych w ochronie dziedzictwa kulturowego na przykładzie mozaiki Anny Fiszer na ścianie kina Neptun w Gdańsku. Celem artykułu jest wykazanie roli inicjatyw społecznych w budzeniu poczucia odpowiedzialności za dziedzictwo materialne i kulturowe. Przyjęto założenie, że dla lokalnych społeczności miasto jest przestrzenią pamięci. Nastrój, atmosfera i klimat miejsca to słowa, które określają fizyczny...
-
A Formal Approach to Model the Expansion of Natural Events: The Case of Infectious Diseases
PublicationA formal approach to modeling the expansion of natural events is presented in this paper. Since the mathematical, statistical or computational methods used are not relevant for development, a modular framework is carried out that guides from the external observation down to the innermost level of the variables that have to appear in the future mathematical-computational formalization. As an example we analyze the expansion of Covid-19....
-
Effect of Overloaded Vehicles on Whole Life Cycle Cost of Flexible Pavements
PublicationThe phenomenon of vehicle overloading—illegal exceeding of maximum legal weight of vehicles, is a serious problem both in developing and developed countries around the world. Overloaded vehicles occur less frequently in comparison to properly loaded vehicles but due to their greater potential to cause damage they significantly contribute to distress of pavement structure. As studies show, the number of overloaded vehicles increases...
-
ESTIMATION OF NONSTATIONARY HARMONIC SIGNALS AND ITS APPLICATION TO ACTIVE CONTROL OF MRI NOISE
PublicationA new adaptive comb filtering algorithm, capable of tracking the fundamental frequency and amplitudes of different frequency components of a nonstationary harmonic signal embedded in white measurement noise, is proposed. Frequency tracking characteristics of the new scheme are studied analytically, proving (under Gaussian assumptions and optimal tuning) its statistical efficiency for quasi-linear frequency changes. Laboratory tests...
-
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...
-
Relative Productivity, Country Size and Export Diversification
PublicationThis paper analyses the effects of productivity and country size on the extent of trade structure diversification. Using a testable version of the Ricardian model, we show that relative export variety is an outcome of two forces: a relative productivity change (technological progress) and a relative country size change (labour force growth). The model predictions are validated empirically using product-level trade data for a sample...
-
USING ARTIFICIAL NEURAL NETWORKS FOR PREDICTING SHIP FUEL CONSUMPTION
PublicationIn marine vessel operations, fuel costs are major operating costs which affect the overall profitability of the maritime transport industry. The effective enhancement of using ship fuel will increase ship operation efficiency. Since ship fuel consumption depends on different factors, such as weather, cruising condition, cargo load, and engine condition, it is difficult to assess the fuel consumption pattern for various types...
-
Analysis of Reasons of Accidents Between Cyclists and Public Transport Vehicles in Cities
PublicationIn European cities, a bicycle is now or is systematically becoming an equal means of transport. Unfortunately, the growth of bicycle traffic is associated with an increase in the number of accidents involving cyclists. Some of these accidents, are events with cyclists and public transport vehicles - and therefore means of transport, which together are to constitute a serious alternative to a car. Although the share of these kind...
-
An Off-Body Channel Model for Body Area Networks in Indoor Environments
PublicationThis paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two...
-
Evaluation of Connectivity Gaps Impact on TCP Transmissions in Maritime Communications
PublicationMany organizations and research working groups, including among others IEEE, ITU, ETSI and IMO are currently working towards improvements in communication of different types of vehicles (cars, trains, planes and vessels) and upgrading utilities and services offered to their crews and passengers travelling all over the world. The paper deals with selected aspects of the TCP protocol connectivity in maritime wireless networks. The...
-
Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
-
Blowing Kinetics, Pressure Resistance, Thermal Stability, and Relaxation of the Amorphous Phase of the PET Container in the SBM Process with Hot and Cold Mold. Part I: Research Methodology and Results
PublicationThe technology of filling drinks without preservatives (such as fresh juices, iced tea drinks, vitaminized drinks) is carried out using hot filling. Mainly due to the production costs and lower carbon footprint, polyethylene terephthalate bottles, commonly called PET, are increasingly used in this technology. In this paper, the main aim is to describe the statistical analysis methodology of the influence of the temperature of the...
-
Wykorzystanie miar dywergencji Csiszara do oecny podobieństwa struktury ludności krajów regionu Morza Bałtyckiego
PublicationStudies of socio-economic phenomena often touch on the issues concerning similarity between demographic structures. The measures usually used in the evaluation of structure similarity or in the investigation of the extent of structural changes are functions of distance metrics of their partial indicators. The study points out the possibility of using Csiszar divergence measures (f-divergences) in the quantification of the extent...
-
Towards detecting programmers’ stress on the basis of keystroke dynamics
PublicationThe article describes the idea of detecting stress among programmers on the basis of keystroke dynamics. An experiment with a group of students of artificial intelligence classes was performed. Two samples of keystroke data were recorded for each case, the first while programming without stress, the second under time pressure. A number of timing and frequency parameters were calculated for each sample. Then statistical analysis...
-
The Efficiency of Polish Stock Market: Ordinal Patterns Approach
PublicationZunino et al. analyzed the problem of discrimination of developed and emergent markets by the use of ordinal patterns methods: number of forbidden patterns and ordinal pattern probability distribution as a basis for entropy and statistical measure of complexity. In this paper we apply the same methodology for the analysis of Polish stock market (index WIG). The results indicate that Polish market belongs neither to developed, nor...