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EN
This paper investigates the variation of track geometrical parameters that lead to a local increase of specific dynamical quantities of a railway vehicle, possibly beyond their acceptable values. In particular, the changes of track geometry are investigated near track points where the running safety or ride comfort are significantly decreased during the vehicle motion due to track irregularities. The investigated dynamical quantities include the lateral and vertical forces at the wheel-rail contact as well as the acceleration of the vehicle body. The vehicle motion has been simulated using a non-linear model of a passenger car moving along a nominally tangent stiff track with random geometrical irregularities. The relationship between the local track condition and the maxima of the dynamical quantities was investigated with the statistical method proposed by the author. The performed analysis clearly identifies the characteristic variation of track irregularities that leads to a large increase of the investigated dynamical quantities at some track points.
2
Content available Cargo securing – comparison of the selected trucks
EN
The paper deals with a comparison of shocks (values of acceleration coefficients and inertial forces) of two types of vehicles (T-810 and T-815 MK IV) during transport experiments on a motorway. The measurement was performed using an OM-CP-ULTRASHOCK-5 three-axial accelerometer with a datalogger and calibration certificate. The goal of the paper is to accept or reject a hypothesis of the existence of a statistically significant difference between the values of the acceleration coefficients generated by the two vehicles. The statistical analysis of the measured data was done with use of two parameters. The results of the analysis show statistically significant differences between the examined vehicles. Based on the performed statistical analysis, the effect on cargo securing is demonstrated.
EN
The article presents a case study of the practical use of BOST surveys to identify the most important factors in chosen enterprise. This article presents an analysis of the answers given to the question contained in the BOST questionnaire, refer-ring to the roof of Toyota’s house. Toyota’s management principles by Jeffrey Liker were pointed out, which refers to elements of Toyota’s house roof. Results of the survey were presented and the proposal to improving the processes in the enterprise. Research results were subjected to statistical analysis with a use of basic statistical parameters. It was made a correlation analysis connected with elements of the Toyota’s house roof. Evaluation structure was presented in a graphic form. Based on the survey results of carried out on the population of production workers, a series of importance areas for improvement was formulated. The aim of the analysis is to present which factors are the most important by building the significance sequences of obtained results .The results obtained for the type of small and medium-sized enterprises overlap with the results of tests verified in other enterprises.
EN
The article presents a case study of the practical use of BOST surveys to identify the most important areas in the production process. It was made the identification of areas from the second Toyota’s management principle point of view. This principle is based on the conviction that appropriate process leads to appropriate results. If the process is designed properly, then good results will come automatically. The research object is company producing the mineral water and carbonated drinks. Some production workers of the company with the help of BOST questionnaire survey showed, which factors are the most important. In frames of the work it was made short characteristics of the research object - producer of mineral water, the presentation of research methodology and content second Toyota’s management principle. Based on the survey results of carried out on the population of production workers, a series of importance areas for improvement was formulated. The aim of the analysis is to present which factors are the most important by building the significance sequences of obtained results. In the article were presented results of analysis with using some statistical tools. The results obtained for the type of small and medium-sized enterprises overlap with the results of tests verified in other enterprises.
EN
This paper presents the results of the analysis of 2 124 forced outages for Eskom subtransmission circuit breakers recorded over the years 2005-15. Statistical techniques are used in the study. Firstly, the actual number of outages and outage rates are calculated and assessed for various event attributes. Further, the dependence between pairs of event attributes is evaluated graphically by plotting bivariate bar graphs and thereafter quantitatively by performing the chi-square test to assess the significance of the results. The insights gained are useful in the management of these breakers.
PL
W artykule przedstawiono analizę wymuszonych przerw w dostawie napięcia w sieci Eskom w latach 2005-2015. Przeprowadzono analizę statystyczną tych wydarzeń. Dodatkowo przeprowadzono nalizę korelacji tych zdarzeń.
PL
Analiza rozwoju elektromobilności w Polsce oraz prognozy liczby pojazdów z napędem elektrycznym do roku 2025
EN
The analysis of e-mobility development in Poland and forecasts of the number electric vehicles by 2025
EN
Apparel industry is not only one of the oldest, largest, labor-intensive, and most global industries but also the typical “starter” industry for countries engaged in export-orientated industrialization. To achieve such dreams, the industry has looked over different inter-dependable factors while producing different products. In this study, an effort has been made to establish a correlation between standard allowed minutes (SAMs) and efficiency of sewing section using different variables, including production rate, number of workstations, and operation breakdown, having a differential impact on both the selected variables. All the empirical analyses were planned in a vertically integrated textile company called Almeda Textile Private Limited Company (PLC), Ethiopia, starting from the basic product category (such as V-neck shirt) up to complicated workwear including military clothing and federal police uniforms of Ethiopia. The Pearson correlation coefficient method was chosen to find the relationship between bivariate linearly scaled variables using Statistical Package for Social Science (SPSS) software. The expected outcome will help in identifying the type of correlation and its significant level as well as its impact on the overall productivity of the sewing section which eventually leads to fulfilling the mission of attaining sustainable production capacity of the mentioned vertically integrated manufacturing company.
EN
High-resolution remote sensing-based hydro-meteorological data products are being increasingly used for various scientifc studies throughout the world. As such, it is important to evaluate the quality of the data retrieved by the means of remotesensing especially for the regions characterized by the drastic variation of topography such as the Himalayas. This work focuses on the comparison and evaluation of the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA–3B43v7) with point-based ground observations recorded by Department of Hydro-Met Services (DHMS) in Bhutan. For this study, 32 rain gauge stations over Southern Himalayas in Bhutan (SHB) were selected and precipitation data for a period of 19 years (from 1998 to 2017) were compared with the TRMM precipitation product. The comparison revealed that the coefcient of correlation between satellite data and ground observation is statistically signifcant at a 95% confdence level. Furthermore, the coefcient of correlation is near unity in some stations and an average of 0.814 over the entire SHB region for 19 years. This fnding imparts that the TRMM can capture the rainfall trend over the SHB. As per the fndings, the average root-mean-square error was 219.1 mm per month considering the entire duration and 344.7 mm per month considering only the rainy season. Similarly, the average Bias was computed at 0.27 for all seasons and 0.32 for the rainy season, indicating TRMM underestimates the precipitation over SHB. The satellite estimate provides a piece of good information on the distribution of rainfall over the SHB. Nevertheless, it is still advisable to correct the bias of the satellite product, as the relative root-mean-square error is larger than 50% for 96% of the evaluated stations.
9
EN
Steel is currently main structural material in the world. Pig iron, which is the basic product of blast furnace process, is the semi-product used in steel-making processes. It is an alloy of iron with carbon containing above 2% C and other elements with limited content, intended for further processing. Chemical composition of pig iron is its basic quality factor, it defines its class and meeting requirements set by steel plant department. It is important that this chemical composition is as stable as possible. In addition, the temperature of pig iron is also very important quality parameter. The paper presents statistical analysis of quality parameters of pig iron produced in one of Polish steelworks. The content of alloying elements and temperature of tapping of pig iron from blast furnace were examined. The amount of non-conforming production and the losses related to the low quality were assessed.
EN
The article presents research results in a scope of evaluation importance of safety in the workplace in the production processes of enterprise from metal products industry. Toyota's management principles by Jeffrey Liker were pointed out, which refers to elements of Toyota’s house roof. An innovative BOST questionnaire survey was characterized as a tool for transformation of Toyota's management principles into questions. Research group which participated in BOST study from the metal product industry was characterized. Research results were subjected to statistical analysis with a use of basic statistical parameters. Research results showed that safety in the workplace is important factor in the company.
EN
The article presents a case study of the practical use of BOST surveys to identify the most important areas that require improvement actions. It was made the identification and of areas requiring improvement from the fourteenth Toyota’s management principle point of view. According to this principle it is crucial to determine the causes of problem by solving technical issues. The research object is company from illumination branch. Some production workers of the company with the help of BOST questionnaire survey showed, which factors can bring the best effect after being improved. In frames of the work it was made characteristics of the research object - producer of illumination, the presentation of research methodology and content fourteenth Toyota’s management principle. Based on the survey results of carried out on the population of production workers, a series of importance areas for improvement was formulated. The aim of the analysis is to present which factors are the most important by building the significance sequences of obtained results. In the article were presented results of analysis with using circular charts, box-and-whisker plots and some statistical tools. The results obtained for the type of small and medium-sized enterprises overlap with the results of tests verified in other enterprises.
PL
W tekście przedstawiono wyniki zastosowania metody MARSplines, należącej do szerokiej grupy metod Data Mining, do prognozowania zapotrzebowania na moc elektryczną w Krajowym Systemie Elektroenergetycznym. Przedstawiono zmienne objaśniające i ich powiązanie ze zmienną prognozowaną. Zamieszczono ponadto obszerną analizę statystyczną tych zmiennych. Na podstawie przeprowadzonych symulacji w trybie ex post i ex ante sformułowano wnioski dotyczące samej metody oraz wnioski wynikające z czynności prognostycznych.
EN
The article presents the results obtained from applying the MARSplines method, which belongs to a broad group of Data Mining methods, to forecast the electric power demand in the Polish National Power System. Furthermore, the relationship between explanatory variables and the forecasted variable is examined through an extensive statistical analysis. Based on the (ex–post and ex–ante) simulations results a number of conclusions are drawn regarding the method itself and the accuracy of its predictions.
EN
In the era of globalisation and permanent travel of people between faraway regions of the world, air transport is one of the most important means of transport. Today it is also one of the most secure transport modest possibilities. This idea stands at the beginning of the article subject. The aim of this work is to present the aviation infrastructure of Mexico and to analyse how it has changed over the years. In this contribution, on the example of Mexico country, a statistical analysis of characteristic parameters determining the development of aviation infrastructure was performed. A statistical analysis of selected aspects may enable to reveal the situation related to air transport in North America and the predictions might visualise expectations in the following years. The factors that determine the development of infrastructure in this country are also presented. The most important elements of the aviation infrastructure, such as airports, are described. They were divided in terms of the number of passengers served and the amount of transported cargo.
PL
W dobie globalizacji i stałych podróży ludzi między odległymi regionami świata transport lotniczy jest jednym z najważniejszych środków transportu. Dziś jest to również jedna z najbezpieczniejszych możliwości transportu. Celem tej pracy jest przedstawienie infrastruktury lotniczej Meksyku i jej analiza jak zmieniła się na przestrzeni lat. W artykule tym na przykładzie kraju meksykańskiego, przeprowadzono analizę statystyczną charakterystycznych parametrów determinujących rozwój infrastruktury lotniczej. Analiza statystyczna wybranych aspektów może umożliwić ujawnienie sytuacji związanej z transportem lotniczym w Ameryce Północnej, a prognozy mogą przedstawiać oczekiwania w kolejnych latach. Przedstawiono również czynniki determinujące rozwój infrastruktury w tym kraju. Opisano najważniejsze elementy infrastruktury lotniczej, takie jak lotniska. Zostały one podzielone pod względem liczby obsługiwanych pasażerów i ilości przewożonego ładunku.
PL
W pracy przedstawiono kompletną procedurę określania niepewności wyników dynamicznych symulacji złożowych spowodowanej brakiem lub ograniczoną informacją o dokładnych danych wejściowych (parametrów) modelu złożowego użytego do symulacji. W szczególności opisano metodę zbioru (ansamblu) równorzędnych wariantów modelu odpowiadających zmiennym wartościom jego parametrów o znanych zakresach tych zmienności oraz prawdopodobieństwach ich rozkładów. Zaprezentowana procedura obejmuje: (i) wybór funkcji celu (wyników symulacji), której niepewność będzie określana; (ii) wybór pełnej listy parametrów modelu (danych wejściowych) o wartościach nieokreślonych lub obarczonych błędami (będących źródłem niepewności wyników symulacji złożowych); (iii) analizę czułości funkcji celu ze względu na niepewność danych wejściowych; (iv) określenie danych wejściowych mających największy wpływ na oszacowanie funkcji celu; (v) próbkowanie przestrzeni danych wejściowych dla zdefiniowania ansamblu modeli symulacyjnych; (vi) wielokrotne symulacje dla znalezienia funkcji celu na ansamblu modeli; (vii) statystyczną analizę uzyskanych wyników. W powyższej procedurze zastosowano statystyczną metodę losowania typu Monte Carlo, a w szczególności metodę próbkowania Latin hypercube sampling. Rezultaty analizy niepewności wyników symulacji są nieodzowne dla ewentualnego wykorzystania modelu złoża do zaawansowanych zastosowań, takich jak optymalizacja procesu sczerpania zasobów złoża ze względu na dobór warunków eksploatacyjnych. Analiza niepewności jest szczególnie ważna w przypadku złóż niekonwencjonalnych, dla których wiele charakterystyk opisujących ich właściwości jest trudnych lub wręcz niemożliwych do uzyskania. Opisaną procedurę zastosowano do realnego przykładu takiego złoża. W jej rezultacie uzyskano niepewność (rozrzut) wyników symulacji uniemożliwiającą wykorzystanie modelu złoża w wymienionej powyżej procedurze optymalizacji. Jednocześnie zastosowana procedura analizy niepewności wskazuje na te parametry modelu, które wymagają uściślenia lub uzupełnienia po to, aby skonstruowany model złożowy nabrał cech niezbędnych do jego pełnego wykorzystania.
EN
The paper presents a complete procedure for determining the uncertainty of the results of dynamic reservoir simulations caused by lack of or limited information about the exact input data (parameters) of the reservoir model used for simulations. In particular, the method of the collection (ensemble) of the equivalent model variants corresponding to the varying values of its parameters with the known ranges of these variations and the probabilities of their distributions are described. The procedure includes: (i) selection of the target function (simulation results) whose uncertainty will be analyzed; (ii) selection of the complete list of model parameters (input data) of uncertain or undefined values; (iii) sensitivity analysis for the target function with respect to the uncertain input data; (iv) determination of the input data that affects the target function to the highest degree; (v) sampling of the input data space to define effective ensemble of the model variants; (vi) multiple simulations of the model ensemble for the target function evaluation; (vii) statistical analysis of the simulation results. The procedure employs the Monte Carlo statistical method to generate the model ensemble and, in particular, Latin Hypercube Sampling. The uncertainty analysis of simulation results is indispensable for the possible application of the reservoir model to more advanced projects such as reservoir production optimization with respect to exploitation system characterization. The uncertainty analysis is especially significant for unconventional reservoir modelling where many model parameters are difficult or even impossible to be determined. The proposed procedure was applied to a realistic example of such a reservoir. The high uncertainty of the basic simulation results, as shown in the paper, makes it impossible to effectively use the model in an optimization procedure. On the other hand, it is worth noting that the proposed procedure indicates, which model parameters are required to be more precisely determined, in order for the it to be accurate enough for reliable applications.
EN
This study contains an analysis of the main determinants of the inflow of foreign direct investment to Poland. This article is the first of the two parts of the cycle and covers theoretical considerations regarding the determinants of foreign direct investment, serving as the introduction to the second, empirical part, in which the research results will be discussed. This study focused on determining the cause-and-effect relationship between the scale of inflow of foreign direct investment and selected macroeconomic parameters of the economy. Based on the theories and results from previous research, a model was developed in which the variables and the nature of their relationship were determined. The model is based on four latent exogenous variables describing FDI determinants and one latent endogenous variable describing FDI inflow. In the article, structural equation modeling was indicated as a method for analyzing the factors conditioning the inflow of foreign direct investment. The proposed research concept will allow supplementing and extending the analysis of FDI determinants in Poland.
PL
Artykuł poświęcony jest analizie głównych motywów warunkujących napływ zagranicznych inwestycji bezpośrednich do Polski. Stanowi pierwszą z dwóch części cyklu i obejmuje rozważania teoretyczne dotyczące determinant podejmowania bezpośrednich inwestycji zagranicznych, będąc tym samym wstępem do drugiej części – empirycznej, w której omówione zostaną wyniki badań. Badania koncentrowały się na określeniu związku przyczynowo-skutkowego między skalą napływu bezpośrednich inwestycji zagranicznych i wybranymi parametrami makroekonomicznymi gospodarki. Na podstawie teorii oraz wyników dotychczasowych badań zbudowano model, w którym określono zmienne i charakter relacji między nimi. Model bazuje na czterech ukrytych zmiennych egzogenicznych opisujących determinanty BIZ oraz jednej ukrytej zmiennej endogenicznej, tj. napływ BIZ. W artykule do analizy czynników warunkujących napływ bezpośrednich inwestycji zagranicznych wskazano metodę równań strukturalnych. Zaproponowana koncepcja badawcza pozwoli na uzupełnienie i rozszerzenie analiz dotyczących determinant BIZ w Polsce.
EN
The paper presents a statistical analysis based on more than 500 fatigue tests available in the scientific literature, for which the influence of thermal treatment of austenitic steel on the low-cycle life of gas turbine exhaust elements is shown. The confidence range of regression parameters for test data is shown and an analysis of variance for different groups of parameters was carried out. Conducted statistical analysis allows to select important parameters affecting the life of the material, while allowing to reject non-essential parameters, which in effect allows correct description of the phenomenon. The collected data from fatigue tests was limited to those whose parameters correspond to the typical work conditions of gas turbine exhaust elements. The tested material is austenitic steel type AISI240 TP304 in various states of heat treatment: aging, tempering and in an as-fabricated condition. The tests were carried out in isothermal conditions with a fast-changing cycle or a cycle with tensile load hold during stretching.
PL
W pracy zaprezentowano analizę statystyczną wykonaną na podstawie ponad 500 wyników prób zmęczeniowych dostępnych w literaturze naukowej, dla których pokazano wpływ obróbki cieplnej stali austenitycznej na trwałość niskocyklową stali austenitycznej. Przeprowadzono analizę regresji dla zgromadzonych danych oraz analizę wariancji dla różnych grup parametrów obróbki cieplnej. Przeprowadzona analiza statystyczna pozwala na wyselekcjonowanie istotnych parametrów wpływających na trwałość materiału, pozwalając jednocześnie odrzucić parametry nieistotne, co w efekcie pozwala na poprawne opisanie zjawiska. W pracy ograniczono użyte dane do odpowiadających typowym parametrom pracy elementów odprowadzających spaliny w turbinach gazowych.
PL
Przeprowadzono badanie dla 33 przypadków leczenia stereotaktycznego w obszarze głowy. Dla każdego przypadku w systemie planowania leczenia Eclipse v.11 został stworzony plan leczenia z wykorzystaniem dynamicznej techniki VMAT (Volumetric Arc Therapy) [1]. Plany radioterapeutyczne realizowano na akceleratorze TrueBeam (Varian Medical System Palo Alto, CA, USA), który wyposażony jest w kolimator wielolistkowy MLC 120 HD [2]. Analizie poddano m.in.: wielkość napromienianych zmian, Indeks Paddicka czy wskaźnik gradientu dawki (Gradient Index) [3]. Dokonano również statystycznej analizy wzajemnych zależności między badanymi parametrami z wykorzystaniem testu korelacji Rho-Spearmana [4]. Przeprowadzona analiza wykazała, że pomiędzy wybranymi badanymi wielkościami występują wzajemne istotne statystycznie korelacje. Taki wynik może być pomocny dla fizyka, sugerując, które parametry mogą być silniej związane z wielkością targetu, pozwalając zaznaczyć potrzebę większego skupienia na wybranych aspektach procesu planowania leczenia.
EN
The study was performed for 33 cases of head stereotactic treatment. For each case, a treatment plan was created using the dynamic VMAT (Volumetric Arc Therapy) technique [1]. Radiotherapy plans were calculated in Eclipse TPS (Treatment Planning System) for TrueBeam accelerator (Varian Medical System, Palo Alto, CA, USA), which is equipped with the MLC 120 HD multi-leaf collimator [2]. For the analysis the following factors were chosen: the size of the irradiated targets, the Paddick Index and the Gradient Index. Additionally statistical analysis of the relationships between the studied parameters was also made using the Rho-Spearman correlation test. The analysis showed that there are mutual statistically significant correlations between the selected quantities tested. Such a result may be helpful for the physicist, suggesting which parameters may be more stronger related to the size of the target, allowing to emphasize the need for greater focus on selected aspects of the treatment planning process.
EN
Before dyeing, woven cotton fabrics have been passed through different pretreatments like desizing, scouring, bleaching and mercerising to enhance quality. In every treatment cotton fabric is treated with different chemicals and mechanical processes. After these treatments, the feel of the fabric has been changed. The change in feel or in terms of the hand value of treated fabrics were analysed by determining the bending length, crease recovery angle, SEM, FTIR, surface roughness and smoothness properties. Other physical properties viz. the tear and tensile strength were also evaluated. Fabric surface roughness and smoothness were determined using the Kawabata Evaluation System (KES) and digital image processing method. Using MATLAB software, digital image processing techniques were used to evaluate the roughness index. The study revealed that the pretreatment process alters the fabric surface. Statistical analysis (ANOVA) was carried out using SPSS software in order to establish the relationship between the pretreatment process effect on the bending length, smoothness and crease recovery angle.
PL
W celu poprawy jakości tkaniny bawełniane przed barwieniem poddawane są obróbce wstępnej składającej się z następujących etapów: odklejanie, szorowanie, wybielanie i merceryzowanie. Podczas każdego etapu tkanina bawełniana jest poddawana różnym procesom chemicznym i mechanicznym. Przebadano tkaniny SEM, FTIR, określono chropowatości powierzchni i gładkość. Oceniono również wytrzymałość na rozdarcie i rozciąganie. Chropowatość i gładkość powierzchni tkaniny określono przy użyciu Kawabata Evaluation System (KES), metody cyfrowego przetwarzania obrazu i oprogramowania MATLAB. Badanie ujawniło, że proces obróbki wstępnej zmienia powierzchnię tkaniny. Wyniki badań poddano analizie statystycznej.
19
Content available remote Predicting automotive sales using pre-purchase online search data
EN
Sales forecasting is an essential element for implementing sustainable business strategies in the automotive industry. Accurate sales forecasts enhance the competitive edge of car manufacturers in the effort to optimize their production planning processes. We propose a forecasting technique that combines keyword-specific customer online search data with economic variables to predict monthly car sales. To isolate online search data related to pre-purchase information search, we follow a backward induction approach and identify those keywords that are frequently applied by search engine users. In a set of experiments using real-world sales data and Google Trends, we find that our keyword-specific forecasting technique reduces the out-of-sample error by 5\% as compared to existing techniques without systematic keyword selection. We also find that our regression models outperform the benchmark model by an out-of-sample prediction accuracy of up to 27%.
EN
The article presents the analysis of the influence of various fixtures of the Y-axis slide of the CMX 70U machining center measured in a coordinate measuring machine. As a result of a series of measurements of the designated geometric features, specific deviations were determined, and statistical calculations were performed on their basis. The further part of the article shows the analysis of the theoretical body deflection under the influence of the force of gravity performed using the MES method in CREO Simulate.
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