Wyniki wyszukiwania - Biblioteka Nauki

1

Chemometria jako wydajne narzędzie analizy danych środowiskowych. Cz 4. Analiza wariacji

100%

Astel A.

LAB Laboratoria, Aparatura, Badania

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2007

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tom R. 12, nr 6

35-39

2

Application of significance analysis to finding root causes of product defects in continuous casting of steel

100%

Rodziewicz A. , Perzyk M.

Computer Methods in Materials Science

|

2016

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tom Vol. 16, No. 4

187--195

EN

The aim of this paper is to present an application of the input variable significance analysis to finding probable causes of product defects occurring in continuous casting (CC) of steel. The research was carried out using production data routinely recorded in one of Polish steel plants and basically referred to defective fraction of billets per heat as the process output. The data did not include the cases with zero defects which made the analysis difficult. The process inputs included eight parameters of different nature (physical, organizational and human). For determining which of the process input parameters are crucial for the output and which of them can be easily eliminated in further analyses two different approaches were applied and compared. The basic tool was an MLP-type Artificial Neural Network in which the relative significance was defined as the sum of the absolute weights of the connections from the given input node to all the nodes in the first hidden layer. As a complementary method the one-way analysis of variance (ANOVA) was utilized in which the value of the F-statistics is used as a measure of the input significance. It was found that the both methods indicate that the start-time of the CC process is the factor highly influencing the fraction of defective products. The process physical parameters which are expected to have a large influence on the billet quality, i.e. deviations from nominal casting temperature and deviation from nominal casting speed also appeared to be significant, moreover their variations also highly depend on the start-time of the CC process. The final conclusion is that the direct cause of the defective products are incorrect adjustments of the casting speed occurring mainly in the morning hours, however not correlated with particular operators. This finding can considerably facilitate the identification of the root cause of the defects by the plant engineers. Some recommendations concerning the future work are also given.

PL

Celem niniejszej pracy jest przedstawienie analizy istotności zmiennych wejściowych jako narzędzia pozwalającego na znalezienie prawdopodobnych przyczyn wad wyrobów w procesie ciągłego odlewania stali. Do analizy wykorzystano dane przemysłowe zebrane w jednej z polskich hut stali, dotyczące produkcji kęsów. Skorzystano z zarejestrowanych danych związanych z przebiegiem i parametrami procesu produkcyjnego, według obowiązujących w zakładzie procedur. Podstawowym źródłem danych była baza tzw. wybraku technologicznego rejestrowanego przez zakład produkcyjny, informująca o fakcie pojawienia się braków oraz ich ilości wyrażonej w procentach dla każdego wytopu. Baza ta nie zawierała jednak pełnej informacji o tych wytopach, w których braki nie występowały, co powodowało istotne trudności i ograniczenia prowadzonych badań. Analizie poddano osiem parametrów wejściowych o różnym charakterze: fizycznym, organizacyjnym i ludzkim. W celu określenia, które z parametrów procesu mają największe znaczenie z punktu widzenia pojawiania sic braków, a które z nich mogą być pominięte, zastosowano i porównano dwie metody. Podstawowym narzędziem były sztuczne sieci neuronowe typu MLP, w których istotność względna jest definiowana jako bezwzględna suma wag połączeń między danym wejściem a wszystkimi węzłami w pierwszej warstwie ukrytej. Drugą metoda była jednoczynnikowa analiza wariancji (ANOVA), badająca wpływ poziomu jednego czynnika klasyfikującego na wartości badanej zmiennej zależnej typu rzeczywistego, określany wartością statystyki F. Otrzymane wyniki pozwalają jed¬noznacznie stwierdzić, że parametr wejściowy ‘pora spustu' ma znaczący wpływ na kształtowanie się parametru wyjściowego ‘udział braków’. Podstawowe fizyczne parametry procesu, tj. odchyłka od nominalnej temperatury odlewania i odchyłka od szybkości odlewania, zgodnie z oczekiwaniami wykazały również duże znaczenie, a ponadto duże zróżnicowanie w zależności od wartości parametru ‘pora spustu’. Końcowym wnioskiem wynikającym z przeprowadzonych analiz jest zidentyfikowanie bezpośredniej przyczyny powstawania wadliwych produktów, którą jest niepoprawne dostosowywanie prędkości odlewania do aktualnej temperatury stali, występujące głównie w godzinach porannych, lecz niezwiązane z konkretnymi pracownikami. Poczynione spostrzeżenia mogą w znaczący sposób ułatwić dokonanie ostatecznej identyfikacji źródeł powstawania wad w wyrobach przez personel inżynieryjny zakładu. W pracy zawarto również zalecenia dotyczące przyszłych badań, zarówno przemysłowych jak i związanych z metodyką prowadzenia podobnych badań.

3

The Significance of Business Localization Factors in the Czech Republic

88%

Jirásková E. , Žižka M.

Creative and Knowledge Society

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2011

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tom 1

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nr 2

16-36

EN

This article is concerned with the significance of individual localization factors during the decision-making of economic subjects regarding the location of their businesses. In the first phase of the research, the investigated localization factors were divided into four groups into regional, local, business, labor and infrastructure. The selected localization factors were investigated with the help of an empirical examination of thirteen selected economic branches in the secondary and tertiary sectors. In subsequent stages, a statistical analysis of the acquired data was performed; the selected economic sections were compared among themselves; and with the help of a diffusion analysis, the dependence of the evaluation on the size of the enterprise and on the economic activities of the selected respondents was investigated. The main goal of the research was to identify the current localization factors associated with supplier and customer markets and to determine their significance. In the context of the research, the hypothesis was verified that despite the existence of various approaches to determining localization factors, in part there are localization factors that act universally in all economic branches and further factors that specifically manifest themselves only in some branches. In the context of each factor, investigated was whether the evaluation of a factor depends on the economic branch and whether it is possible to consider an investigated factor as universal. It was also determined whether or not the evaluation of a factor is directly proportionate to the size of the business. From the research results, it follows that during localization, businesses place the greatest significance on the availability of information and communications technologies, geographic proximity to customers, availability of qualified human resources and on transportation costs. Localization decision-making is affected by many factors and depends on a large number of circumstances.

4

An attempt at identification sources of variation in monthly net incomes among persons with tertiary education

88%

Targaszewska M.

Econometrics. Ekonometria. Advances in Applied Data Analytics

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2013

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nr 1(39)

210-221

EN

The paper presents the results of the analysis of factors differentiating the level of monthly net incomes in Poland. In the first step of the research, one-way ANOVA was applied in order to verify whether the level of education influences incomes. Subsequently, it was investigated whether such variables as sex, age, the class of residence, region, experience, study major and occupation additionally differentiate the incomes of persons with a higher education. The analysis makes use of the individual data from Social Diagnosis gathered in 2009. All the calculations were performed with the application of IBM SPSS STATISTICS 20 package.

5

STUDY TO DEVELOP A CO-RELATIONSHIP BETWEEN WATER QUALITY AND LAND USE PATTERN AS INDEX OF RIVERINE WETLAND WITH STATISTICAL APPROACH

88%

Roy M. B. , Kumar A. , Ghosh A. , Roy P. K.

Quaestiones Geographicae

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2020

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tom 39

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nr 1

EN

This investigation additionally recognizes partner cooperation issue and furthermore to moderate the real issue through subjective and quantitative appraisal of riverine wetland. Considering a floodplain wetland in rustic West Bengal, the concentration was extended to perceive the type of wetland capacities as per the idea of individuals’ contribution by group examination. Be that as it may, NDVI was connected to ponder the total weeds condition into the wetland to decide the connection between Water Quality Index (WQI) with Normalized Difference Vegatation Index (NDVI) and its impact on valuation. In ANOVA, which is computed by MINITAB programming, centrality level was lower than 0.05 for each case.

6

Impact of logistics information systems on supply chain optimization: Case of Group Bachir Rachid

88%

Belkacem Bouzida I. , Merzoug S.

Journal of Sustainable Development of Transport and Logistics

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2021

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tom Vol. 6, No. 2

60--80

EN

Purpose: This paper aims to check the contribution of Logistics Information Systems - LIS to supply chain optimization in the steel industry group of Bachir Rachid. This group that owns eight independent companies and numerous points of sale and warehouses, has to be connected by such advanced systems to ensure effectiveness and profitability. Methodology: A questionnaire was distributed among a group of employees, and the collected data was later analyzed by SPSS 25 and complemented by further structured and unstructured interviews. We have realized an analysis of variance to evaluate the impact of LIS on logistics activities, supply chain management, and integration as well as optimization. The test of Kruskal-Wallis H was chosen due to the non-linearity of the data. Results: This work proves that Logistics Information Systems contribute to the performance of logistics activities, supply chain integration, and supply chain optimization through the enhancement of the efficiency of supply chain management and by the reduction of supply chain costs. The theoretical contribution: The contribution made to the theory of logistics and supply chain management lies in confirming previous findings on the contribution of LIS to logistics and supply chain optimization in Algeria, and more specifically, in the steel industry.

7

A Statistical Analysis of Evaporative Pattern Casting Process Parameters for the Production of Aluminum Alloy Components

88%

Omidiji B. V.

Journal of Casting & Materials Engineering

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2020

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tom Vol. 4, no. 3

41--47

EN

Four process parameters were investigated with the aim of determining their influence on the mechanical properties of some test castings, bars, cylinders and plates. The influence was quantified in terms of percentage contribution. Analysis of variance (ANOVA), regression, main effects and interaction effects plots were employed to carry out the statistical analysis. As regards the tensile strength of the test castings, the geometry of components (GOC) dominated, contributing 90.83% and the pouring temperature (PT) contributed 91.90% influence on the hardness property. These dominating potentials of these two parameters limited the interaction of the parameters studied in the research. statistical analysis. As regards the tensile strength of the test castings, the geometry of components (GOC) dominated, contributing 90.83% and the pouring temperature (PT) contributed 91.90% influence on the hardness property. These dominating potentials of these two parameters limited the interaction of the parameters studied in the research.

8

Checking MTL Properties of Discrete Timed Automata via Bounded Model Checking

88%

Woźna-Szcześniak B. , Zbrzezny A.

Fundamenta Informaticae

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2014

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tom Vol. 135, nr 4

553--568

EN

We investigate a SAT-based bounded model checking (BMC) method for MTL (metric temporal logic) that is interpreted over linear discrete infinite time models generated by discrete timed automata. In particular, we translate the existential model checking problem for MTL to the existential model checking problem for a variant of linear temporal logic (called HLTL), and we provide a SAT-based BMC technique for HLTL. We show how to implement the BMC technique for HLTL and discrete timed automata, and as a case study we apply the technique in the analysis of GTPP, a Generic Timed Pipeline Paradigm modelled by a network of discrete timed automata.

9

Metodyczne aspekty analizy hałasu wewnętrznego w środkach transportu miejskiego

75%

Andrzejczak K. , Tomaszewski F. , Orczyk M.

Prace Naukowe Politechniki Warszawskiej. Transport

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2016

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tom z. 114

9--18

PL

W artykule przedstawiono zastosowanie jednoczynnikowej analizy wariancji ANOVA do oceny rozkładu poziomu dźwięku we wnętrzu autobusu Solaris Urbino 12 m podczas fazy rozpędzania. Na podstawie wykonanych pomiarów hałasu we wnętrzu autobusu sformułowano pytanie czy poziom hałasu podczas fazy rozpędzania jest równomiernie rozłożony na całej długości autobusu. Aby odpowiedzieć na tak zadane pytanie i zastosować testy analizy wariancji ANOVA należało spełnić kilka warunków: w pierwszej kolejności sprawdzono spełnienie podstawowego założenia analizy wariancji tj. czy badany hałas w każdym punkcie pomiarowym ma rozkład normalny, ponadto dla kompletności badania normalności przeprowadzono testy normalności Kołmogorowa-Lillieforsa, test Cramera von Misesa oraz test jednorodności wariancji dla wszystkich punktów pomiarowych.Następnie zastosowano j ednoczynnikową analizę wariancj i ANOVA oraz na zakończenie przedstawiono graficzny rozkład 95% przedziałów ufności poziomów dźwiękuw poszczególnych lokalizacjach mikrofonów pomiarowych podczas fazy rozpędzania autobusu.

EN

This article presents application of univariate analysis of variance ANOVA to assess distribution of sound level inside bus Solaris Urbino 12 m during speeding up. On the basis of measurements of noise inside the bus a ąuestion was worded if the level of noise during acceleration is evenly distributed in the whole length of the bus. To answer such question and to apply tests of analysis of variance ANOVA a few conditions have to be met. First it is checked if the basie assumption of analysis of variance i.e. if measured noise in each measurement point has normal distribution, moreover for completeness of normality examination, normality tests of Kolmogorov-Lilliefors, test of Cramer von Mises and homoscedasticity test of variance for all measurement points were carried. Next one factor analysis of variance ANOVA was applied. In conclusion a graphic distribution of 95% of confidence intervals of sound levels of specific locations of measurement microphones during acceleration of the bus was presented.

10

Application of the analysis of variance for the determination of reinforcement structure homogeneity in MMC

75%

Gawdzińska K. , Berczyński S. , Pelczar M. , Grabian J.

Archives of Foundry Engineering

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2010

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tom Vol. 10, iss. 1

35-38

EN

These authors propose a new definition of homogeneity verified by variance analysis. The analysis aimed at quantitative variables describing the homogeneity of reinforcement structure, i.e. surface areas, reinforcement phase diameter and percentage of reinforcement area contained in a circle within a given region. The examined composite material consisting of silicon carbide reinforcement particles in AlSi11 alloy matrix was made by mechanical mixing.

11

Parametric Sensitivity Analysis of Factors Affecting Sound Transmission Loss of Multi-Layered Building Elements Using Taguchi Method

75%

Garg N. , Kumar A. , Maji S.

Archives of Acoustics

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2014

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tom Vol. 39, No. 2

165--176

EN

The paper presents application of Taguchi method in optimizing the sound transmission loss through sandwich gypsum constructions and those comprising of masonry concrete blocks and gypsum boards in order to investigate the relative influence of the various parameters affecting the sound transmission loss. The application of Taguchi method for optimizing sound transmission loss has been rarely reported. The present work uses the results analytically predicted on “Insul” software for various sandwich material configurations as desired by each experimental run in an L8 orthogonal array. The relative importance of the parameters on single-number rating, Rw (C, Ctr) is evaluated in terms of percentage contribu- tion using Analysis of Variance (ANOVA). The ANOVA method reveals that type of studs, steel stud frame and number of gypsum layers attached are the key factors controlling the sound transmission loss characteristics of sandwich multi-layered constructions.

12

Zastosowanie klasyfikacji pojedynczej do oceny podziału skał złożowych i otaczających na strop, złoże i spąg na przykładzie kopalni "Rudna"

75%

Galiński A. , Mertuszka P. , Strzelecki M. , Wojtaszek A.

Górnictwo i Geoinżynieria

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2011

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tom R. 35, z. 2

235-242

PL

W pracy pokazano, że podział skał złożowych i otaczających na strop, wyrobisko i spąg jest statystycznie istotny. Ocenę podziału oparto na analizie wariancji i klasyfikacji pojedynczej. Badania przeprowadzono dla sześciu parametrów górotworu, która zawierała dokumentacja pomiarów.

EN

It was shown in the paper that differentiation of rock massif into roof, seam and floor rocks is statistically significant. Variance analysis and one parameter classification were utilized to carry out required computation. Six rock parameters from laboratory data were taken into account.

13

A description of particle shape homogeneity in the space of composite suspension casting

75%

Gawdzińska K. , Berczyński S. , Chylińska R. , Grabian J.

Archives of Foundry Engineering

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2011

|

tom Vol. 11, iss. 1s

11-14

EN

The presented analysis of the particle shape homogeneity of the reinforcement phase in the space of composite casting is made by means of the descriptive statistics method and the analysis of variance. The reinforcement phase consisted of SiC particles with 15% content, while the matrix was an AlSi11 alloy. The composites were made by the mechanical stir casting method.

14

Hybrid GRA-PCA and modified weighted TOPSIS coupled with Taguchi for multi-response process parameter optimization in turning AISI 1040 steel

75%

Sultana, Mst. Nazma , Dhar N. R. , Sultana, Mst. Nazma , Dhar N. R.

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nr 1

15

The situation of generations on the labour market in Poland

75%

WIKTOROWICZ J.

Economic and Environmental Studies

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2018

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tom 18

|

nr 2

995-1015

EN

A generational shift is perceived as a significant challenge to organisations, especially in the ongoing changes in contemporary labour market. Four generations meet in the workplace now, while until recently one could talk only about two. Given the growing significance of human capital as a substantial factor of economic growth, the knowledge about individual generations is gaining importance. The aim of this article is to assess the position of particular generations on the labour market in Poland. The statistical analysis was carried out using the individual data of Social Diagnosis 2015 and allows for a quantitative assessment of the working situation of employees from different generations. Basic statistical tests to compare the population, as well as the multifactorial analysis of variance were applied.

PL

Współczesny rynek pracy zmienia się, a jako istotne wyzwanie dla organizacji postrzega się m.in. zmiany generacyjne. W miejscu pracy spotykają się obecnie cztery pokolenia, podczas gdy jeszcze niedawno były to dwie generacje. Biorąc pod uwagę rosnące znaczenie kapitału ludzkiego jako ważnego czynnika wzrostu gospodarczego, wiedza na temat generacji zyskuje na znaczeniu. Celem artykułu jest ocena pozycji poszczególnych pokoleń na rynku pracy w Polsce. Analiza statystyczna przeprowadzona została z wykorzystaniem indywidualnych danych Diagnozy Społecznej 2015 i pozwala na dokonanie ilościowej oceny sytuacji zawodowej pracujących z różnych generacji. Zastosowano podstawowe testy służące porównaniu populacji oraz wieloczynnikową analizę wariancji.

16

Comparison of information on sleep apnoea contained in two symmetric EEG recordings

75%

Prucnal M. A. , Polak A. G.

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nr 2

17

Homogeneity of particle size in the space of composite suspension casting

75%

Gawdzińska K.

Archives of Foundry Engineering

|

2010

|

tom Vol. 10, iss. 1 spec.

163--168

EN

The presented analysis of the reinforcement particle size homogeneity in the space of composite casting is made by means of descriptive statistics methods and the analysis of variance. The reinforcement phase consisted of SiC particles with 15% content, while the matrix was an AlSi11 alloy. The composites were made by the mechanical stir casting method.

18

Statistical analysis of impact of visual impairment on postural stability

75%

Jureczko M. , Jureczko P.

Modelowanie Inżynierskie

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2018

|

tom T. 38, nr 69

37--42

EN

The main aim of the presented research was assessment of postural stability in patients with various degree of visual impairment. The article contains basic explanation and requirements for stabilography research. Statistical analysis of impact of degree of visual impairment on postural stability opposed to people perfectly sighted was also conducted. The studies were conducted on 45 patients with various degree of visual impairment and 15 patients perfectly sighted. Postural stability was tested using diagnostic platform Zebris. The test results showed relationship between postural stability and degree of impairment and in line with them it can be stated that visual control has a significant impact on stability.

PL

Głównym celem przeprowadzonych badań była ocena stabilności postawy u pacjentów z różnym stopniem niepełnosprawności wzrokowej. Artykuł zawiera podstawowe wyjaśnienia i wymagania dotyczące badań nad stabilografią. Przeprowadzono analizę statystyczną wpływu stopnia upośledzenia wzroku na stabilność postawy w stosunku do osób doskonale widzących. Badania przeprowadzono na 45 pacjentach z różnym stopniem zaburzeń widzenia i 15 doskonale widzących. Stabilność postawy testowano przy użyciu urządzenia diagnostycznego firmy Zebris. Przeprowadzone badania dały wyniki pokazujące wpływ stopnia upośledzenia wzroku na stabilność postawy człowieka. Badania wykazały, że kontrola wizualna ma znaczący wpływ na stabilność człowieka.

19

On a New Approach to the Analysis of Variance for Experiments with Orthogonal Block Structure.

75%

Calinski T. , Siatkowski I.

Biometrical Letters

|

2017

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tom 54

|

nr 2

91-122

EN

Summary The main estimation and hypothesis testing results are presented for experiments conducted in proper block designs. It is shown that, under appropriate randomization, these experiments have the convenient orthogonal block structure. Because of this, the analysis of experimental data can be performed in a comparatively simple way. Certain simplifying procedures are introduced. The main advantage of the presented methodology concerns the analysis of variance and related hypothesis testing procedures. Under the adopted approach one can perform them directly, not by combining results from intra-block and inter-block analyses. Application of the theory is illustrated by three examples of real experiments in proper block designs. This is the first of a projected series of papers concerning the analysis of experiments with orthogonal block structure.

20

Impact of cereal diseases on the qualitative traits of spring barley breeding lines

75%

Zawieja B. , Bakinowska E. , Bichoński A. , Pilarczyk W.

Biometrical Letters

|

2017

|

tom 54

|

nr 1

77-90

EN

The differences between individual breeding lines of spring barley and a control variety were tested in terms of several measured (continuous) and qualitative traits. The impact of the qualitative traits (diseases) on the quantitative traits, especially yield, was assessed on the basis of the significance of differences for both qualitative traits and yield. Depending on the type of trait, either a logistic model or analysis of variance was used as a statistical tool. The statistically significant differences between some breeding lines and the control variety were shown. It was observed that in fodder barley both infection by mildew and lodging influenced yield. The results of analyses obtained in the so-called pre-preliminary trials and preliminary trials were different. This fact confirmed the necessity of repeating trials over several years.