Search
Filters
total: 492
filtered: 315
Search results for: MULTIVARIATE%20STATISTICS
-
Searching for Solvents with an Increased Carbon Dioxide Solubility Using Multivariate Statistics
PublicationIonic liquids (ILs) are used in various fields of chemistry. One of them is CO2 capture, a process that is quite well described. The solubility of CO2 in ILs can be used as a model to investigate gas absorption processes. The aim is to find the relationships between the solubility of CO2 and other variables—physicochemical properties and parameters related to greenness. In this study, 12 variables are used to describe a dataset...
-
Application of multivariate statistics in assessment of green analytical chemistry parameters of analytical methodologies
PublicationThe study offers a multivariate statistical analysis of a dataset, including the major metrological, “greenness” and methodological parameters of 43 analytical methodologies applied for aldrin determination (a frequently analyzed organic compound) in water samples. The variables (parameters) chosen were as follows: metrological (LOD, recovery, RSD), describing the “greenness” (amount of the solvent used, amount of waste generated)...
-
Box-spline histograms for multivariate density estimation
PublicationW pracy podano ujednoliconą konstrukcję estymatora pochodnych gęstości oraz stałych asymptotycznych dla tej gęstości. Posłużono się histogramami box-splinowymi. Skorzystano z twierdzeń asymptotycznych dla operatorów związanych z tymi estymatorami.
-
Application of Multivariate Analysis Methods in Welding Engineering
PublicationPhenomena and processes taking place during welding are usually very complex and, for this reason, should be described using multivariate methods. The article discusses the methodological basis and selected application areas as regards the solving of welding problems using statistical multivariate methods. In addition, the article presents exemplary applications of the design of experiment, multiple regression analysis, cluster...
-
On Noncausal Identification of Nonstationary Multivariate Autoregressive Processes
PublicationThe problem of identification of nonstationary multivariate autoregressive processes using noncausal local estimation schemes is considered and a new approach to joint selection of the model order and the estimation bandwidth is proposed. The new selection rule, based on evaluation of pseudoprediction errors, is compared with the previously proposed one, based on the modified Akaike’s final prediction error criterion.
-
Multivariate Statistical Approach for Nephrines in Womenwith Obesity
PublicationCatecholamines are physiological regulators of carbohydrate and lipid metabolism during stress, but their chronic influence on metabolic changes in obese patients is still not clarified. The present study aimed to establish the associations between the catecholamine metabolites and metabolic syndrome (MS) components in obese women as well as to reveal the possible hidden subgroups of patients through hierarchical cluster analysis...
-
Sampling Strategies: Statistics of Sampling
PublicationEach step of the analytical procedure has a significant influence on the final result of the analysis. In the majority of cases the analytical procedure encompasses sampling because the analysis of the entire object (material) is usually not possible. Thus it is necessary to include the uncertainty related to sampling procedure in the uncertainty budget calculations. In the paper: the most important properties of the analysed...
-
Chemometrics and Statistics | Multicriteria Decision Making
PublicationThis contribution describes the application of Multicriteria Decision Making tools in analytical chemistry. The general scheme of MCDM is presented to show its general steps. The most frequently applied in analytical sciences MCDM techniques – AHP, ELECTRE, PROMETHEE and TOPSIS – are briefly described and their advantages and disadvantages are discussed. The applications in analytical chemistry are selection of an appropriate...
-
Multivariate models of inter-resonator couplings for microwave filter synthesis
PublicationArtykuł przedstawia technikę budowy modeli częstotliwości rezonansowej, współczynnika sprzężenia między rezonatorami oraz sprzężenia ze źródłem/obciążeniem. Przedstawiony jest model siedmiu zmiennych uwzglęgniający topologię rezonatorów. Na podstawie modelu wykonana została synteza filtrów mikrofalowych.
-
On adaptive covariance and spectrum estimation of locally stationary multivariate processes
PublicationWhen estimating the correlation/spectral structure of a locally stationary process, one has to make two important decisions. First, one should choose the so-called estimation bandwidth, inversely proportional to the effective width of the local analysis window, in the way that complies with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive...
-
On Adaptive Spectrum Estimation of Multivariate Autoregressive Locally Stationary Processes
PublicationAutoregressive modeling is a widespread parametricspectrum estimation method. It is well known that, in the caseof stationary processes with unknown order, its accuracy canbe improved by averaging models of different complexity usingsuitably chosen weights. The paper proposes an extension of thistechnique to the case of multivariate locally stationary processes.The proposed solution is based on local autoregressive...
-
OECD Guidelines for Micro Statistics on Household Wealth
PublicationThis report reflects the contributions of members of the OECD Expert Group on Micro Statistics on Household Income, Consumption and Wealth. Members of the Expert Group included representatives from National Statistical Offices – Bob McColl (Chair, Australia); Alison Hale (Canada); Andre Bustamante and David Niculcar (Chile); Henrik Sejerbo Soerensen (Denmark); Yafit Alfandari (Israel); Shinji Yoshioka (Japan); Sinho Kim...
-
Assessment of river water quality in the South Baltic coast by multivariate techniques
Publication -
Regularized Local Multivariate Reduced-Order Models With Nonaffine Parameter Dependence
PublicationThis paper addresses a singular problem, not yet discussed in the literature, which occurs when parametric reduced-order models are created using a subspace projection approach with multiple concatenated projection bases. We show that this technique may lead to the appearance of localized artifacts in the frequency characteristics of a system, even when the reduced-order projection basis is rich enough to describe the original...
-
On adaptive selection of estimation bandwidth for analysis of locally stationary multivariate processes
PublicationWhen estimating the correlation/spectral structure of a locally stationary process, one should choose the so-called estimation bandwidth, related to the effective width of the local analysis window. The choice should comply with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive estimation variance. The paper presents a novel method...
-
Application of higher order statistics in the analysis of electrochemical processes
PublicationZjawiska nieliniowe są często spotykane w elektrochemicznych pomiarach korozyjnych. Z drugiej strony linearyzacja zagadnień elektrochemicznych jest uznaną i powszechną praktyką. W niniejszej pracy przedstawiono możliwość poszerzenia interpretacji badanych procesów elektrodowych o techniki oparte na analizie widmowej rzędu wyższego od 2. Autorzy skupili się na analizie szumu elektrochemicznego generowanego podczas polaryzacji katodowej,...
-
Higher-Order Statistics for Fluctuation-Enhanced Gas-Sensing.
PublicationPrzedstawiono wyniki badań eksperymentalnych wykrywania wybranych mieszanin gazów za pomocą analizy fluktuacji rezystancji obserwowanych w sensorach gazu. Do analizy obserwowanych fluktuacji wykorzystano gęstość widmową mocy oraz funkcję bispektrum.
-
Ordinal pattern statistics for the assessment of heart rate variability
PublicationThe recognition of all main features of a healthy heart rhythm (the so-called sinus rhythm) is still one of the biggest challenges in contemporary cardiology. Recently the interesting physiological phenomenon of heart rate asymmetry has been observed. This phenomenon is related to unbalanced contributions of heart rate decelerations and accelerations to heart rate variability. In this paper we apply methods based on the concept...
-
Classification and fingerprinting of kiwi and pomelo fruits by multivariate analysis of chromatographic and spectroscopic data
PublicationThe fingerprinting capacity of two analytical techniques, HPLC and UV-Vis spectroscopy in the case of fruits samples (kiwi and pomelo) has been investigated. The multivariate exploratory techniques were used for sample discrimination according to the fruit species and subspecies. The combination of principal component analysis with linear discriminant analysis is opening new directions in the fingerprinting analysis. The classifications...
-
Active Control of Highly Autocorrelated Machinery Noise in Multivariate Nonminimum Phase Systems
PublicationIn this paper, a novel multivariate active noise control scheme, designed to attenuate disturbances with high autocorrelation characteristics and preserve background signals, is proposed. The algorithm belongs to the class of feedback controllers and, unlike the popular feedforward FX-LMS approach, does not require availability of a reference signal. The proposed approach draws its inspiration from the iterative learning control...
-
Multivariate evaluation by quality indicators of no-tillage system in Argiudolls of rolling pampa (Argentina)
Publication -
Multivariate Features Extraction and Effective Decision Making Using Machine Learning Approaches
Publication -
Optimal control of multivariable ship propulsion system.
PublicationCelem pracy jest analiza i synteza algorytmu oraz struktury optymalnego regulatora wielowymiarowego układu napędowego statku na podstawie teorii sterowania optymalnego. W tym celu sformułowano oryginalny nieliniowy zero-wymiarowy ciągły w czasie i oparty na chwilowej wartości zmiennej stanu (w odróżnieniu od wartości średnich modelu matematycznego całego układu napędowego statku). Ten model zweryfikowano na podstawie wyników doświadczalnych...
-
Surface water quality assessment by the use of combination of multivariate statistical classification and expert information
PublicationThe present study deals with the assessment of surface water quality from an industrial-urban region located in northern Poland near to the city of Gdansk. Concentrations of thirteen chemicals includingtotal polycyclic aromatic hydrocarbons (PAHs), halogenated volatile organic compounds (HVOCs) and major ions in the samples collected at five sampling points during six campaigns were used as variablesthroughout the study. The originality...
-
Multivariate statistical comparison of analytical procedures for benzene and phenol determination with respect to their environmental impact
PublicationThe studydescribesthepossibilityofapplicationofself-organizingmapstechniquetoassessthe greenness ofanalyticalmethodologies.Themetrologicaland “environmentalimpact” parametersof proceduresforbenzeneandphenoldeterminationinwatersamplesweresetsofinputdatafor chemometric analysis.Totally47objectsand8variablesformedthedatausedforanalysis.Themajor factors responsiblefornon-greencharacterofthemethodologyaretheamountoforganicsolventand amount...
-
Multivariate analysis of impedance data obtained for coating systems of varying thickness applied on steel
PublicationElectrochemical impedance spectroscopy (EIS) has proven to be a valuable test method for the electrochemical characterization of protective coatings on metals. The common way of analysis in impedance spectroscopy is to model the impedance spectrum by means of an equivalent circuit and to extract the quantity of interest using optimization techniques. A model, corresponding to the behavior of the sample under testing, is important...
-
Fish target strength estimation using multiple echo statistics
PublicationW pracy przedstawiono sposób określania statystycznych właściwości charakterystyki wiązki systemu hydroakustycznego z uwzględnieniem możliwości pojawienia się echo wielokrotnych od jednej ryby. Przedstawiono modele obejmujące dwa teoretyczne przypadki związane z wzajemnym ruchem statku i pojedynczej ryby i pokazano, że posiadają one zbliżone właściwości statystyczne. Rozważania teoretyczne potwierdzone są analizą przykładowych...
-
Effect of Polymerization Statistics on the Electronic Properties of Copolymers for Organic Photovoltaics
PublicationStatistical block copolymers, composed of donor (D) and acceptor (A) blocks, are a novel type of material for organic photovoltaics (OPVs) devices. In particular a new series of polymers based on PBTZT-stat-BDTT-8, recently developed by Merck, offers high solubility in different solvents, and a high power conversion efficiency (PCE) in different device architectures. Although it is known that the electronic properties of these...
-
Statistics with R A Handbook for Statistical Analysis with R and R-Studio
PublicationIf you are to perform any kind of data (statistical) analysis and use tools in the data science ecosystem, you may have seen a variety of tutorials, handbooks online (I’m not mentioning traditional bibles of statistics). Unfortunately most of them is written intentionally for specific purposes and/or target group of people and does not include many aspects, data types, difficult aspects, usually hiding them trying to solve theoretical...
-
Atmospheric and Surface Water Pollution Interpretation in the Gdańsk Beltway Impact Range by the Use of Multivariate Analysis
PublicationOpracowanie dotyczny zastosowania hierarchicznej analizy klastrów i testów nieparametrowych celem dokonania interpretacji wpływu Obwodnicy Trójmiejskiej. W większości przypadków wykryto obecność oddziaływań antropogenicznych (zastosowanie nawozów, transport, posypywanie dróg solą w okresie zimowych) jak i pół-środowiskowych (aerozole morskie, erozja materiałów budowlancyh). Nie wykrytu jednak ścisłej zależności okresowej dla zanieczyszczeń...
-
Efficient recovery of electrophoretic profiles of nucleoside metabolites from urine samples by multivariate curve resolution
Publication -
New semi-causal and noncausal techniques for detection of impulsive disturbances in multivariate signals with audio applications
PublicationThis paper deals with the problem of localization of impulsive disturbances in nonstationary multivariate signals. Both unidirectional and bidirectional (noncausal) detection schemes are proposed. It is shown that the strengthened pulse detection rule, which combines analysis of one-step-ahead signal prediction errors with critical evaluation of leave-one-out signal interpolation errors, allows one to noticeably improve detection results...
-
Self-assembly of vertically oriented graphene nanostructures: multivariate characterisation by Minkowski functionals and fractal geometry
PublicationThe enormous self-assembly potential that graphene and its derived layered materials offer for responding to the contemporary environmental challenges has made it one of the most investigated materials. Hence, tuning its extraordinary properties and understanding the effect at all scales is crucial to tailoring highly customised electrodes. Vertically oriented graphene nanostructures, also known as carbon nanowalls (CNWs), due...
-
Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples
PublicationIn the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application...
-
Generalised heart rate statistics reveal neurally mediated homeostasis transients
PublicationDistributions of accelerations and decelerations, obtained from increments of heart rate recorded during a head-up tilt table (HUTT) test provide short-term characterization of the complex cardiovascular response to a rapid controlled dysregulation of homeostasis. A generalised statistic is proposed for evaluating the neural reflexes responsible for restoring the homeostatic dynamics. An evaluation of the effects on heart rate...
-
Teaching High Performance Computing Using BeesyCluster and Relevant Usage Statistics
PublicationThe paper presents motivations and experiences from using the BeesyCluster middleware for teaching high performance computing at the Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology. Features of BeesyCluster well suited for conducting courses are discussed including: easy-to-use WWW interface for application development and running hiding queuing systems, publishing applications as services...
-
Optimal Multivariable Control for Modified Z-source Based IPT
Publication -
Optimal Multivariable Control for Modified Z-source Based IPT
PublicationThis paper describes Z-source based inductive power transfer topologies control approaches. The goal of this work is a multi-variable control approach which involves a constant voltage/constant current control along with an optimal frequency control to obtain maximum efficiency. This control is applied to the wireless power transfer system based on a modified Z-source topology. The description of the control method along with simulation...
-
Preoperative factors predicting saphenous vein graft occlusion in coronary artery bypass grafting: a multivariate analysis
Publication -
Lattice filter based multivariate autoregressive spectral estimation with joint model order and estimation bandwidth adaptation
PublicationThe problem of parametric, autoregressive model based estimation of a time-varying spectral density function of a multivariate nonstationary process is considered. It is shown that estimation results can be considerably improved if identification of the autoregressive model is carried out using the two-sided doubly exponentially weighted lattice algorithm which combines results yielded by two one-sided lattice algorithms running...
-
Authentication of whisky due to its botanical origin and way of production by instrumental analysis and multivariate classification methods
PublicationHeadspacemass-spectrometry (HS-MS), mid infrared (MIR) and UV–vis spectroscopywere used to authenticate whisky samples from different origins and ways of production ((Irish, Spanish, Bourbon, TennesseeWhisky and Scotch). The collected spectra were processed with partial least-squares discriminant analysis (PLS-DA) to build the classification models. In all cases the five groups ofwhiskieswere distinguished, but the best resultswere...
-
On the possibility of estimating fish length distribution from its target strength statistics.
PublicationArtykuł przedstawia koncepcję odtwarzania rozkładu długości ryb na podstawie danych z przeszukiwań akustycznych. Wykorzystując metody odwrotne w statystycznym przetwarzaniu rozkładu siły celu ryb pokazano, że przy pewnych założeniach co do rozkładu położenia ryb w wiązce, możliwa jest estymacja szukanego rozkładu długości ryb.
-
Non-parametric application of Tsallis statistics to systems consisting of M hydrogen molecules
Publication -
Complementary use of GCxGC–TOF–MS and statistics for differentiation of variety in biosolid samples
PublicationFormation of biosolid cakes, which are one of the main wastes generated in wastewater treatment plants, is connected with emission of many hazardous chemical compounds, including odoriferous ones. To optimize particular processes of biosolid cake processing, it is necessary to assess chemical composition of the gas mixtures containing the compounds released from the cakes. The paper proposes application of two-dimensional gas chromatography...
-
KOLMOGOROV EQUATION SOLUTION: MULTIPLE SCATTERING EXPANSION AND PHOTON STATISTICS EVOLUTION MODELING
PublicationWe consider a formulation of the Cauchy problem for the Kolmogorov equation which corresponds to a localized source of particles to be scattered by a medium with a given scattering amplitude density. The multiple scattering amplitudes are introduced and the corresponding series solution of the equation is constructed. We investigate the integral representation for the first series terms, its estimations and values of the photon...
-
thestats: An Open-Data R Package for Exploring Turkish Higher Education Statistics
PublicationThere are open datasets available for official statistics, finance, education, and a variety of other domains. The open datasets are published by third-party vendors as well as official authorities. For example, The Turkish Higher Education Council maintains a web portal dedicated to higher education in Türkiye. Detailed datasets about universities, faculties, and departments can be obtained from the portal. Using the data provided...
-
Multivariate Statistical Analysis for Mutual Dependence Assessment of Selected Polyphenols, Organic Acids and Metals in Cool-Climate Wines
PublicationPolyphenols, organic acids and metal ions are an important group of compounds that affect the human health and quality of food and beverage products, including wines. It is known that a specific correlation between these groups exist. While wines coming from the New World and the Old World countries are extensively studied, wines coming from cool-climate countries are rarely discussed in the literature. One of the goals of this...
-
Identification of nonstationary multivariate autoregressive processes– Comparison of competitive and collaborative strategies for joint selection of estimation bandwidth and model order
PublicationThe problem of identification of multivariate autoregressive processes (systems or signals) with unknown and possibly time-varying model order and time-varying rate of parameter variation is considered and solved using parallel estimation approach. Under this approach, several local estimation algorithms, with different order and bandwidth settings, are run simultaneously and compared based on their predictive performance. First,...
-
Application of Multivariate Adaptive Regression Splines (MARSplines) Methodology for Screening of Dicarboxylic Acids Cocrystal Using 1D and 2D Molecular Descriptors
PublicationDicarboxylic acids (DiAs) are probably one of the most popular cocrystals formers. Due to the high hydrophilicity and non-toxicity, they are promising solubilizes of active pharmaceutical ingredients (APIs). Although DiAs appear to be highly capable of forming multicomponent crystals with various compounds, some systems reported in the literature are physical mixtures the solid state without forming stable intermolecular complex....
-
Determination of mercury in mosses by novel cold vapor generation atmospheric pressure glow microdischarge optical emission spectrometry after multivariate optimization
Publication