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EN
The authors determined the accuracy and reliability of yielding models by using the values of two differently obtained indices – the leaf area index (LAI) obtained through direct surface measurements, and the normalized difference vegetation index (NDVI) obtained through spatial remote sensing of crops. The study based on the drip-irrigated sweet corn yielded the data obtained in the field experiment held in the semi-arid climate on darkchestnut soil in the South of Ukraine. The suitability of the LAI and NDVI for the simulation of sweet corn yields was estimated by the regression analysis of the yielding data by correlation (R) and determination (R2) coefficients. Additionally, mathematical models for the crop yields estimation based on the regression analysis were developed. It was determined that LAI is a more suitable index for the crop yield prediction: the R2 value was 0.92 and 0.94 against 0.85 for the NDVI-based models.I It was determined that it is better to use the LAI values obtained at the stage of flowering, when R2 averaged to 0.94, and the NDVI-based models does not depend on the crop stage (the R2 was 0.85 both for the flowering and ripening stages of the plant development). The combined NDVI-LAI model showed that there is no necessity in the complication of the LAI-based model through introduction of the remotely sensed index because of insignificant improvement in the performance (R2 was 0.94 and 0.92).
EN
This publication presents the research aimed at developing statistical models, on the basis of which it was possible to prepare credible forecasts of unit cost and coal net output for longwalls in 5 hard coal mines in Poland. The argument has been verified that there is a dependence between the level of nuisance and the level of costs, as well as longwall production results. A research procedure has been developed for that purpose, which aimed at developing two statistical models connecting the nuisance due to geological and mining conditions with costs and longwall production results. The multiple linear regression technique has been used to develop statistical models. The set of data taken into account in the analyses comprised 120 longwalls mined in the years 2010–2019. Two models have been developed – one for forecasting unit costs, the other for forecasting coal net output. Subsequently, the models’ forecasting ability has been verified on a sample of historical data. A relative forecast error for 75% of observations has been in the range of (–25%; +37%). That result has been considered satisfactory. Subsequently, using those models, forecasts of unit costs and coal net output have been prepared for 220 longwalls planned for mining in the years 2020–2030. Those forecasts have been prepared in the stipulated ranges of geological and mining nuisance influencing mining process, by means of dedicated W Ue and W Ut factors. The nuisance models for forecasting purposes have been developed using the AHP (Analytic Hierarchy Process) method. The research hypothesis has been confirmed on the basis of the obtained results. An increase in the level of nuisance leads to an increase in the unit costs for longwalls and the deterioration of production results. Unit operating costs for longwalls in specific ranges of nuisance may differ by up to 30%, being in the range of 52.0–120.3 zł/Mg. Likewise, the coal daily output of longwalls may be even 22% lower, having the average level in the range of 1.89–3.61 thousand Mg/d.
PL
Publikacja prezentuje badania zmierzające do opracowania modeli statystycznych, na podstawie których możliwe było wykonanie wiarygodnych prognoz kosztu jednostkowego i wydobycia netto ścian w 5 kopalniach węgla kamiennego w Polsce. Weryfikowano tezę, że istnieje zależność pomiędzy poziomem uciążliwości a wielkością kosztów i wynikami produkcyjnymi ścian. W tym celu opracowano procedurę badawczą prowadzącą do skonstruowania dwóch modeli statystycznych wiążących uciążliwość warunków geologicznych i górniczych z kosztami i wynikami produkcyjnymi ścian. Do skonstruowania modeli statystycznych posłużono się techniką regresji wielorakiej. Zbiór danych, które uwzględniono w analizach, obejmował 120 ścian eksploatowanych w latach 2010–2019. Powstały dwa modele – jeden dla celów prognozowania kosztów jednostkowych, drugi – produkcji węgla netto. Następnie wykonano weryfikację zdolności prognostycznej tych modeli w próbie danych historycznych. Względny błąd prognozy dla 75% obserwacji wahał się w przedziale (–25%; +37%), a jego średnia wartość dla wszystkich obserwacji nie przekraczała 5% dla obu tych modeli. Wynik ten, mimo defektów modelowania liniowego, uznano za satysfakcjonujący. Następnie przy użyciu tych modeli wykonano prognozy kosztów jednostkowych i coal net output dla 220 ścian planowanych do wydobycia w latach 2020–2030. Prognozy te wykonano w umownych przedziałach uciążliwości geologicznych i górniczych warunków procesu eksploatacji za pomocą wskaźników WUe i WUt. Modele uciążliwości dla celów prognostycznych skonstruowano z wykorzystaniem metody AHP (Analytic Hierarchy Process). Na bazie otrzymanych wyników teza badawcza została potwierdzona. Wzrost uciążliwości prowadzi do wzrostu kosztu jednostkowego ścian i pogorszenia wyników produkcyjnych. Zależność ta nie jest liniowa. Koszty jednostkowe ścian w poszczególnych przedziałach uciążliwości mogą się wahać nawet do 30%, mieszcząc się w przedziale 52,0–120,3 zł/Mg. Podobnie również wydobycie dobowe ze ścian może być niższe nawet o 22%, i kształtować na poziomie średnim w przedziale 1,89–3,61 tys. Mg/d.
EN
In this paper, we randomly select 75 sets data of calcium sulfate hemihydrate (CSH) content and initial setting time, and the traditional test method of CSH and analyses initial setting time was used by complexometric titration. So the close relationship between them was studied in depth, which classification fitting data to be analyzed by regression analysis. The result shows that this regression analysis method can accurately determine CSH content in modified industrial by-product gypsum. The determination method has the advantages of simplification and rapid operation. As well as, the XRF quantitative analytical method was used to test the CSH content, which verified the accuracy of regression analysis method. The results also show that this method has high accuracy, and can simplify the traditional experimental process. The method developed is easier and more convenient and has broad prospects in application.
EN
This study was aimed at analyzing the influence of the cutting parameters (spindle speed, feed rate and cutting depth) on the surface roughness of the machined parts with the influence of the machining stability of the cutter. In order to consider the chattering effect, the machining stabilities were calculated based on the measured tool tip frequency response functions. A series of machining tests were conducted on aluminum workpieces under different cutting parameters. Then, the surface roughness prediction models in the form of nonlinear quadratic and power-law functions were established based on the multivariable regression method, in which the input parameters, cutting depth and spindle speed, were respectively defined in the stable and unstable regions, according to the stability lobes diagram. The current results show that both models built with the cutting parameters defined in stable regions demonstrate higher prediction accuracy of the surface roughness, about 90%, when compared with the models defined in full regions with the accuracy of about 80%. In particular, the power-law model is proven to have 90% prediction accuracy when validated with the cutting parameters in a stable region. As a conclusion, the mathematical models based on the cutting parameters with well-defined machining stability were proven to show more accurate prediction ability of the surface roughness. It could be expected that the prediction model can further be applied to optimize the machining conditions in low speed roughing and high speed finishing process with desirable surface quality.
EN
This paper presents an investigation of impact strength of sponge gourd, coir, and jute fibers reinforced epoxy resin-based composites. Impact strength of specimens, made of composites with various proportions of wt% ratio of resin and hardener, wt% of resin and hardener, wt% ratio of sponge gourd and jute, wt% ratio of sponge gourd and coir, was measured. Design of experiment was done by Taguchi method using four control factors with three levels. Effect of the above control factors on impact strength was examined and the best combinations of control factors are advised. Confirmation test was performed by using this combination and the percentage of contribution of the above factors on impact strength was investigated by Analysis of Variance (ANOVA). Contour and interaction plots provide helpfully examines to explore the combined influences of different control factors on output characteristics. The regression equation represents a mathematical model that relates control factors with impact strength.
EN
The article is aimed at the development of the analytical approach for evaluating the parameters of the Basset force acting on a particle in two-dimensional fluid flow induced by the oscillating wall. By applying regression analysis, analytical expressions to determine complementary functions were established for evaluating the Basset force. The obtained dependencies were generalized using the infinite power series. As a result of studying the hydrodynamics of a two-phase flow, analytical dependencies to determine the Basset force were proposed for assessing its impact on particles of the dispersed phase in a plane channel with the oscillating wall. It was discovered that the Basset force affects larger particles. However, in the case of relatively large wavelengths, its averaged value for the vibration period is neglected. Additionally, the value of the Basset force was determined analytically for the case of relatively small wavelengths. Moreover, it was discovered that its impact can be increased by reducing the wavelength of the oscillating wall.
EN
Purpose: The paper presents empirical formulas for the calculation of Continuous Cooling Transformation (CCT) diagram basing on the chemical composition and austenitizing temperature. Design/methodology/approach: In the method of calculating CCT diagrams proposed in the paper, two types of tasks are solved. First task is classification and consists in determining the range of cooling rate for particular phase transformations. The second task is regression, which aims at calculating the transformations temperature, hardness and volume fraction of phases in steel. The model of CCT diagrams was developed using multiple regression and logistic regression methods. Research limitations/implications: CCT diagrams can be calculated according to the presented method, if the chemical composition of steel meets the criteria defined by the application range of the model. Practical implications: The formulas presented in the article can be used to determine the conditions for heat treatment of structural steels. Originality/value: The paper presents the method for calculating CCT diagrams of the structural steels and engineering steels, depending on their chemical composition as well as austenitizing temperature.
EN
The content of this paper is dedicated to the analysis of the flat planarity of forklift stacker’s track and cross sections of lanes between racks in a warehouse. These results will serve as a basis for a possible reconstruction of the track and racks and shall contribute to the overall reduction of costs related to an unexpected bad technical condition. The contribution aims to assess the geometric parameters of warehouse racks at the selected company operation in terms of their suitability for further use. The choice of the selected topic represents a relevant issue, which can be possibly encountered in daily practice related to the storage and transport processes of products. The measurements and processing of longitudinal profiles and cross-sections were made in the local coordinate and local vertical system. Points on the lower, middle and upper level of racks were measured for good and correct interpretation of results. Testing the measured positional change of poles is on the end of this paper. The immediate readiness of interest groups of subjects for adopting necessary actions to ensure the stability and safe operation of the whole network of lanes of the warehouse spaces is the expected contribution of the presented results.
EN
Hedonic pricing models in real property valuation have been frequently applied in many research studies and projects since it was introduced by Rosen in 1974. The development of Geographic Information Systems (GIS) in the recent decades has gradually supports the usage of hedonic model in the spatial data pricing model studies. Beside the basic advantages of GIS to position properties in terms of their geographic coordinates, it has the capabilities of dealing with reasonable amount of data, and wide choices of analysis that make it powerful tool to facilitate the building and implementation of the hedonic models within its framework. Many studies have employed GIS in real property valuation in their present work and for the future prediction. This paper reviews the works of literature on the GIS applications in the real property valuation employing the hedonic pricing models.
PL
Okno składa się z kilku elementów konstrukcyjnych o zróżnicowanych wartościach parametrów fizykalnych. Istnieje potrzeba opracowania uniwersalnego algorytmu do obliczania współczynnika przenikania ciepła wieloskrzydłowej stolarki okiennej. Celem artykułu jest analiza współczynnika przenikania ciepła wieloskrzydłowej stolarki okiennej w zależności od wybranych czynników. Tematem artykułu jest określenie wpływu fizykalnych właściwości cieplnych elementów stolarki okiennej (współczynnik przenikania ciepła oszklenia Ug; współczynnik przenikania ciepła ramy Uf ; liniowy współczynnik przenikania ciepła mostka termicznego ψg,f ) na współczynnik przenikania ciepła wieloskrzydłowej stolarki okiennej w budynkach mieszkalnych. Analiza wykonana została na podstawie opracowanego deterministycznego modelu matematycznego. Wyznaczono optymalne wartości parametrów dla wieloskrzydłowej stolarki okiennej, są to: Ug = 0,30 W/(m2·K); Uf = 0,80 W/(m2·K); ψg,f = 0,03 W/(m·K); r = 1. Wielkości te pozwalają na osiągnięcie minimalnej wartości współczynnika przenikania ciepła Uw,min = 0,493 W/(m2·K).
EN
The window consists of several construction elements with different values of physical parameters. There is a need to create a universal algorithm for calculating the heat transfer coefficient for multi-sash widows. The aim of this publication is to analyze the heat transfer coefficient of multi-sash windows depending on the selected factors. In the physical characteristics of thermal parameters of windows (heat transfer coefficient of glazing Ug, heat transfer coefficient of frame Uf, linear heat transfer coefficient thermal bridge ψg,f) on the heat transfer coefficient of multi-sash windows in residential buildings. Analysis made on the basis of a developed deterministic mathematical model. It was found that the optimal values of the parameters tested for multi-sash windows are: Ug = 0,30 W/(m2K); Uf = 0,80 W/(m2K); ψg,f = 0,03 W/(mK); r = 1. They allow to achieve a minimum value of Uw,min = 0,493 W/(m2K).
PL
W artykule przedstawiono zastosowanie modelu regresji do oszacowania współczynnika izolacyjności akustycznej przegrody niejednorodnej na przykładzie przegrody dwumateriałowej. Sformułowano model regresji, następnie zastosowano go do wyznaczenia izolacyjności płyty. Uzyskane wyniki porównano z wynikami pomiarów.
EN
Paper discussed the regression model which was used to determine the sound insulation of a two-materials baffle based on the known sound insulation of its layers.
EN
Mechanical properties of aluminum-silicon alloys are defined by condition of alloying components in the structure, i.e. plastic metallic matrix created from solid solution &alpha on the basis of Al, as well as hard and brittle precipitations of silicon. Size and distribution of silicon crystals are the main factors having effect on field of practical applications of such alloys. Registration of crystallization processes of the alloys on stage of their preparation is directly connected with practical implementation of crystallization theory to controlling technological processes, enabling obtainment of suitable structure of the material and determining its usage for specific requirements. An attempt to evaluate correlation between values of characteristic points laying on crystallization curves and recorded with use of developed by the author TVDA method (commonly denominated as ATND method) is presented in the paper together with assessment of hardness of tested alloy. Basing on characteristic points from the TVDA method, hardness of EN AC-AlSi9Mg alloy modified with strontium has been described in the paper in a significant way by the first order polynomial.
EN
In this study, the aim was to model the toxic effect of copper (Cu) and analyse the removal of Cu in aqueous Saharan and non-Saharan mediums by Lemna minor. Two separate test groups were formed: with Saharan dust (S) and without Saharan dust (WS). These test groups were exposed to 3 different Cu concentrations (0.05, 0.50 and 5.00 ppm). Time, concentration, and group-dependent removal efficiencies were compared using the non-parametric Mann-Whitney U test and statistically significant differences were found. The optimum removal values were tested at the highest concentration 79.6% in the S medium and observed on the 4th day for all test groups. The lowest removal value (16%) was observed at 0.50 ppm on the 1st day in the WS medium. When the S medium and WS medium were compared, in all test groups Cu was removed more successfully in the S medium than the WS medium contaminated by Cu in 3 different concentrations of (0.05 ppm, 0.50 ppm, 5.00 ppm). The regression analysis was also tested for all prediction models. Different models were performed and it was found that cubic models show the highest predicted values (R2). The R2 values of the estimation models were found to be at the interval of 0.939–0.991 in the WS medium and 0.995–1.000 in the S medium.
EN
The selection of the formwork system for high rise building affects the entire construction project duration and cost. The study reports the factors influencing the selection of different formwork system in the construction of high rise buildings through structural questionnaire survey from the client, contractor, consultant, and interviews with expert members. Total of 40 technical factors was identified from the literature and 220 filled questionnaires were received from the respondent. Relative Importance Index method is used to find the topmost factors affecting the selection of formwork system. Additionally, from factor analysis 22 factors were identified to have a correlation with one another. Regression analysis reveals that duration of the project, maintenance cost, adaptability, and safety have impact on formwork selection across time, cost and quality. These findings could potentially increase the construction company’s existing knowledge in relation to formwork selection.
EN
In the article the features of energy summation from two wind generators, located at a certain distance from each other, are considered. The method of calculating the correlation function between the wind flow speed change functions in the direction of wind distribution is presented. The formulas for describing the fluctuation components of energy at the output of the wind generator are given for two cases: when the phases of the fluctuations of the wind flow on two wind generators are the same and when the fluctuations of the wind flow are in the antiphases. It is shown that to increase the energy level that can be taken from the wind power plant it is necessary to control the phase shift between the energy fluctuations at the output of the wind generators and use the energy of the storages; and to use linear approximations to approximate the wind speed change function. Under the condition of a linear change of the internal resistance of the wind generator in time, it is advisable to introduce the wind speed change function with linear approximations. The system of orthonormal linear functions based on Walsh functions is given. A table with formulas and graphs describing the first 8 functions, which are arranged in order of increasing the number of their sign alternating on the interval of functions definition, is presented. The result of the approximation of the wind speed change function with a system of 8 linear functions based on Walsh functions is shown. Decomposition coefficients, mean-square and average relative approximation errors for such approximation are calculated. In order to find the parameters of multiple linear regression the method of least squares is applied. The regression equation in matrix form is given. An example of application of linear regression prediction method to simple functions is shown. The restoration result for wind speed change function is shown. Decomposition coefficients, mean-square and average relative approximation errors for restoration of wind speed change function with linear regression method are calculated.
EN
Prestige, reputation, brand, image simply “enterprise goodwill” as an economic phenomenon has attracted attention of economic experts since the nineteenth century. Even though there are many various methodologies and approaches, its evaluation and quantification is still a challenge. Identification of key sources of goodwill creation and its management is the challenge for managers of enterprises. Which determinants are able to create enterprise goodwill - this question is the main aim in this study. This study identifies significant sources of the enterprise goodwill creation based on the residual income in the Slovak Republic. The data set of Slovak enterprises, which consists of 11483 financial statements of Slovak enterprises in 2016, was created for the research. As a main statistical method the multiple linear regression analysis is used. Based on the results we have identified return on equity, net income previous year, retained earning prior years, valuable rights, marketing costs and investments to the plant as key sources of enterprise goodwill creation. Additionally, we have created an econometric model, which could be used for evaluation of enterprise goodwill by companies’ management.
PL
Prestiż, reputacja, marka, wizerunek, po prostu "wartość przedsiębiorstwa" jako zjawisko, przyciągają uwagę ekspertów od XIX wieku. Mimo że istnieje wiele różnych metodologii i podejść, jej ocena i kwantyfikacja nadal stanowią wyzwanie. Identyfikacja kluczowych źródeł powstawania wartości firmy i zarządzania nią jest wyzwaniem dla menedżerów przedsiębiorstw. Które determinanty są w stanie stworzyć wartość przedsiębiorstwa - to pytanie jest głównym celem niniejszego badania. W badaniu zidentyfikowano znaczące źródła tworzenia wartości firmy w oparciu o dochód rezydualny w Republice Słowackiej. Do badań stworzono zbiór danych, pochodzących ze słowackich przedsiębiorstw, który składa się z 11483 sprawozdań finansowych z 2016 r. Jako główną metodę statystyczną zastosowano analizę wielorakiej regresji liniowej. W oparciu o wyniki, jako kluczowe źródła tworzenia wartości firmy, zidentyfikowano zwrot z kapitału własnego, zysk netto z poprzedniego roku, zachowane zyski z lat ubiegłych, cenne prawa, koszty marketingowe oraz inwestycje w zakład. Dodatkowo stworzono model ekonometryczny, który można wykorzystać do oceny wartości firmy przez kierownictwo.
EN
The capital structure has been of interest for researchers in the field of financial theory for over 60 years. However, literature surveys show that relatively few studies on the structure of capital and the factors shaping it can be applied to the TSL industry. The TSL (Transport, Spedition, Logistics) sector belongs to industries with a high development potential, both in the world and Poland. In order to meet the need for the diagnosis of the TSL industry in Poland, the research was undertaken to identify and examine the strength and direction of the impact of selected factors on the capital structure of enterprises in the TFL sector in Poland. The article consists of two parts. The first part explains the issues related to defining the concept of capital structure and includes identification of capital structure determinants based on the literature. The second part shows research methods, describes the sample, defines variables and presents results of the research. The enterprises listed on the NewConnect market were the subject of the research. It was to achieve the set goal that the correlation analysis and the linear regression method were used. Both correlation analysis and regression analysis have not confirmed the significance of all seven capital structure determinants. The correlation analysis has confirmed the significance of four determinants: asset structure, profitability, company size and financial liquidity. The regression analysis has also confirmed the statistical significance of the four determinants; these are: the structure of assets, size of the company, financial liquidity and the effective tax rate. The analysis of correlation shows that the level of indebtedness is positively correlated with the size of the enterprise and profitability, while negatively, with the structure of assets and financial liquidity. In turn, the regression analysis shows that the level of indebtedness is positively correlated only with one variable: the size of the enterprise, while negatively with the three variables: the structure of assets, financial liquidity and the effective tax rate.
PL
Struktura kapitału jest przedmiotem zainteresowania badaczy z zakresu teorii finansów od ponad 60 lat. Studia literatury wskazują jednak, że stosunkowo niewiele badań dotyczących struktury kapitału i kształtujących ją czynników dotyczy przedsiębiorstw branży TSL. Branża TSL (Transport, Spedycja, Logistyka) należy do branż o wysokim potencjale rozwoju, zarówno w skali świata, jak i Polski. Wychodząc naprzeciw potrzebie diagnozy branży TSL w Polsce podjęto badania, których celem było zidentyfikowanie oraz zbadanie siły i kierunku wpływu wybranych czynników na strukturę kapitału przedsiębiorstw branży TSL w Polsce. Artykuł składa się z dwóch części. W pierwszej części, na podstawie literatury przedmiotu wyjaśniono zagadnienia związane z definiowaniem pojęcia struktura kapitału oraz dokonano identyfikacji determinant struktury kapitału. W drugiej części omówiono metody badawcze, scharakteryzowano próbę, określono zmienne oraz przedstawiono wyniki badań. Przedmiotem badań były przedsiębiorstwa notowane na rynku NewConnect. Do realizacji postawionego celu wykorzystano analizę korelacji oraz analizę regresji liniowej. Zarówno analiza korelacji, jak i analiza regresji nie potwierdziły istotności wszystkich siedmiu przyjętych w badaniu determinant struktury kapitału. Analiza korelacji potwierdziła istotność czerech determinant: struktury aktywów, rentowności, wielkości firmy, płynności finansowej. Analiza regresji potwierdziła również statystyczną istotność czterech determinant, przy czy są to: struktura aktywów, wielkość firmy, płynność finansowa oraz efektywna stopa podatkowa. Z analizy korelacji wynika bowiem, że z poziomem zadłużenia pozytywnie skorelowana jest wielkość przedsiębiorstwa oraz rentowność, natomiast negatywnie – struktura aktywów i płynność finansowa. Z kolei z analizy regresji wynika, że poziom zadłużenia pozytywnie skorelowana jest tylko jedna zmienna – wielkością przedsiębiorstwa, natomiast negatywnie trzy zmienne – struktura aktywów, płynnością finansową oraz efektywna stopa podatkowa.
PL
Okno składa się z kilku elementów ze zróżnicowanymi wartościami parametrów fizykotechnicznych. Istnieje potrzeba stworzenia uniwersalnego algorytmu do obliczania współczynnika przenikania ciepła przez stolarkę wieloskrzydłową. Celem niniejszej publikacji jest analiza współczynnika przenikania ciepła przez wieloskrzydłową stolarkę okienną w zależności od wybranych czynników. W prezentowanym artykule pokazano charakter i stopień wpływu wybranych czynników (powierzchni okna, udziału powierzchni szklonej do powierzchni okna, współczynnika przenikania ciepła oszklenia oraz współczynnika przenikania ciepła ramy i liczby skrzydeł okiennych) na współczynnik przenikania ciepła wieloskrzydłowej stolarki okiennej w budynkach mieszkalnych. Analiza wykonana na podstawie opracowanego deterministycznego modelu matematycznego. Ustalono, że optymalne wartości zbadanych parametrów dla wieloskrzydłowej stolarki okiennej to: Ao = 2,366 m2; C = 0,95; Ug = 0,20 W/(m2K); Uf = 0,70 W/(m2K); r = 1. Pozwalają one osiągnąć minimalną wartość współczynnika Uw, min = 0,476 W/(m2K).
EN
The window consists of several elements with different values of physico-technical parameters. There is a need to create a universal algorithm for calculating the heat transfer coefficient of multi-wing windows. The aim of this article is to analyze the coefficient of heat transfer of multi-wing window joinery according to selected factors. The article presents the nature and degree of influence of selected factors (window surface, glass surface area, the heat transfer coefficient values of glazed surfaces and frames and the number of wings in the window) on the heat transfer coefficient of multi-wing window joinery in residential buildings. The analysis was based on a deterministic mathematical model. It was found that the optimum values for the tested parameters for multi-wing windows are: Ao = 2,366 m2; C = 0,95; Ug = 0,20 W/(m2K); Uf = 0,70 W/(m2K); r = 1. They allow to achieve a minimum value of Uw, min = 0,476 W/(m2K).
19
Content available remote Application of Multivariate Analysis Methods in Welding Engineering
EN
Phenomena 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 analysis, principal component analysis and logistic regression analysis. The application of multivariate analyses provides the possibility of performing the mathematical description of joining processes, which, after verification, could be used to predict results of such processes, particularly in relation to the properties and fatigue service life of welded structures.
PL
Zjawiska i procesy zachodzące podczas spajania są zazwyczaj bardzo złożone i należy je opisywać metodami wielowymiarowymi. W artykule opisano podstawy metodologiczne i wybrane obszary zastosowania rozwiązywania problemów spawalniczych z wykorzystaniem statystycznych metod wielowymiarowych. Przedstawiono przykłady użycia teorii planowania eksperymentu, analizy regresji wielokrotnej, analizy skupień, analizy składowych głównych i analizy regresji logistycznej. Zastosowanie analiz wielowymiarowych daje możliwość matematycznego opisu procesów spajania, co można, po przeprowadzeniu weryfikacji merytorycznej, wykorzystywać do przewidywania ich skutków, a zwłaszcza do prognozowania właściwości i trwałości eksploatacyjnej konstrukcji spawanych.
EN
The purpose of this study is to identify relationships between the values of the fluidity obtained by computer simulation and by an experimental test in the horizontal three-channel mould designed in accordance with the Measurement Systems Analysis. Al-Si alloy was a model material. The factors affecting the fluidity varied in following ranges: Si content 5 wt.% – 12 wt.%, Fe content 0.15 wt.% – 0.3 wt. %, the pouring temperature 605°C-830°C, and the pouring speed 100 g · s-1 – 400 g · s-1. The software NovaFlow&Solid was used for simulations. The statistically significant difference between the value of fluidity calculated by the equation and obtained by experiment was not found. This design simplifies the calculation of the capability of the measurement process of the fluidity with full replacement of experiments by calculation, using regression equation.
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