24 Hits in 0.55 sec

The Smoothed Bootstrap Fine-Tuning

Renata Dwornicka, Andrii Goroshko, Jacek Pietraszek
2019 System Safety: Human - Technical Facility - Environment  
The bootstrap method is a well-known method to gather a full probability distribution from the dataset of a small sample. The simple bootstrap i.e. resampling from the raw dataset often leads to a significant irregularities in a shape of resulting empirical distribution due to the discontinuity of a support. The remedy for these irregularities is the smoothed bootstrap: a small random shift of source points before each resampling. This shift is controlled by specifically selected distributions.
more » ... The key issue is such parameter settings of these distributions to achieve the desired characteristics of the empirical distribution. This paper describes an example of this procedure.
doi:10.2478/czoto-2019-0091 fatcat:xodo25vf3rbqnhjjexz5uuviey

Analysis of quality control efficiency in the automotive industry

Andrzej Pacana, Karolina Czerwińska, Renata Dwornicka
2021 Transportation Research Procedia  
Andrzej Pacana, Karolina Czerwinska, Renata Dwornicka/ Transportation Research Procedia 00 (2021) Results and analysis As part of the correlation analysis between the frequency of each type of inspection  ...  Andrzej Pacana, Karolina Czerwinska, Renata Dwornicka/ Transportation Research Procedia 00 (2021) 000-000 The analysis of the relationship between the type of quality control methods and their participation  ... 
doi:10.1016/j.trpro.2021.07.037 fatcat:dcfekvq5b5g5hnsq556eobklim

The outline of the expert system for the design of experiment

Renata Dwornicka, Jacek Pietraszek
2018 Production Engineering Archives  
The design of experiment (DoE) is a methodology originated from early 1920s when Fisher's papers created the analysis of variance and first known experimental designs: latin squares. It is focused on a construction of empirical models based on measurements obtained from specifically structured and driven experiments. Its development resulted in the constitution of four distinctive branches recognized by the industry: factorials (full or fractional), Taguchi's robust design, Shainin's Red-X®and
more » ... response surface methodology (RSM). On one hand, the well-known success stories of this methodology implementations promise great benefits, while on other hand, the mathematical complexity of mathematical and statistical assumptions very often lead to improper use and wrong inferences. The possible solution to avoid such mistakes is the expert system supporting the design of experiments and subsequently the analysis of obtained data. The authors propose the outline of such system and provides the general analysis of the ontology and related inference rules.
doi:10.30657/pea.2018.20.09 fatcat:qlly6ylp7vcwled5aifasuetxu

Reliability of Variability Source Detection in Shainin's Component Search Procedure

Jacek Pietraszek, Renata Dwornicka, Andrii Goroshko
2019 Quality Production Improvement - QPI  
Shainin's component search procedure uses variability source detection based on specific median test. This approach has only two triple subsets and the certainty of inference can be weak for this reason. This paper checks this approach by series of numerical simulations.
doi:10.2478/cqpi-2019-0048 fatcat:llvjx4u2q5gflcac5wv6vbinya

ICT development on the example of selected software applied in manufacturing area

Agnieszka Szczotok, Renata Dwornicka, R. Ulewicz, B. Hadzima
2018 MATEC Web of Conferences  
This paper provides an insight into a few selected aspects of computer-aided software usage in the manufacturing processes. This research aims to point out a diversity of software used in manufacturing area which is available on the market and to summarize most of the functionalities of three selected types of software for production zone backing.
doi:10.1051/matecconf/201818301010 fatcat:6arynwade5f4xozelzq4gj4tym

Design Principles of Horizontal Drum Machines with Low Vibration

Ilona Drach, Andrii Goroshko, Renata Dwornicka
2021 Advances in Science and Technology Research Journal  
Using the example of washing machines using the linear theory of vibrations, the dynamics of horizontal rotary drum machines is investigated and the basic requirements for their layout are formulated to reduce vibration activity. The mathematical equations of vibrations of the multiply connected system tub-drum on elastic suspensions are compiled for main types of washing machines and centrifuges with horizontal axis of rotation. The problem is solved in a linear setting based on the Lagrange
more » ... uation of the second kind. The accuracy and adequacy of the mathematical model was tested directly on a full-scale object by measuring noise, vibrations, support forces and stress distribution in individual elements and units of the washing machine in the entire range of drum rotation frequencies. Investigations of the nature of system vibrations depending on changes in the position and attachment points of elastic and damping elements were carried out using simulation in the Simulink environment. As a result of the research, the basic requirements for the layout of horizontal rotary drum machines were experimentally confirmed. Experimental verification was carried out to confirm the results obtained. It has been experimentally proven that the improvement of the experimental setup to reduce its vibration activity increases the efficiency of using direct-acting liquid autobalancers.
doi:10.12913/22998624/136441 fatcat:wje6sqcwdvbijftg4tgtfrpqam

Improvement Of The Production Process With The Use Of Selected Kpis

Czerwińska Karolina, Andrzej Pacana, Renata Dwornicka
2020 System Safety: Human - Technical Facility - Environment  
AbstractFaced with ever-increasing customer demands and global competition, companies are forced to look for production reserves, increase efficiency and productivity. Hence, the need to monitor the use of the machine park has arisen, making it possible to identify waste and production reserves in the implemented technological processes. The aim of the article is to evaluate the effectiveness of the production line of internal frame doors and to analyze the correctness of the use of selected
more » ... indicators of the production process effectiveness. This article proposes a response to the problems formulated in manufacturing companies, including practical aspects of the use of specific measures to assess the effectiveness of the use of technical infrastructure. The solutions presented in the article can be used in practice for improvements in production units.
doi:10.2478/czoto-2020-0038 fatcat:2jjoibvxqbhchegxdgtpkox25u

The Bootstrap Method As A Tool To Improve The Design Of Experiments

Renata Dwornicka, Norbert Radek, Jacek Pietraszek
2019 System Safety: Human - Technical Facility - Environment  
The paper considers the use of the bootstrap method to improve the determination of confidence intervals identified by the DOE (design of experiment) procedure. Two different approaches have been used: one that is appropriate for factorial designs and the other one relevant to the methodology of the response surface. Both approaches were tested on the real experiment datasets and compared with the results obtained from the classical statistical expressions based on well-known asymptotic formulas derived from the t distribution.
doi:10.2478/czoto-2019-0092 fatcat:as7wugnwineovgkw3svzta6w7i

Tribological Properties of Oxide Coatings Produced on EN AW-5251 Alloy using Different Distances between Electrodes

Marek Bara, Renata Dwornicka
2019 Quality Production Improvement - QPI  
The subject of the presented work was the analysis of the influence of the distance between the electrodes using in the coating process on the tribological properties of oxide coatings. Oxide coatings were prepared on EN AW-5251 aluminum alloy samples. The samples surfaces were subjected to hard anodizing process in a multicomponent electrolyte based on sulfuric acid with an addition of organic acids. Anodizing was carried out with a constant electric charge density of 180 A·min/dm2. The
more » ... es between the electrodes for subsequent samples increased every 0.125 m up to 1 m. The tribological partner in a sliding couple with oxide layers was pin of PEEK/BG. Tribological tests were conducted on a T-17 tester in reciprocating motion, in technically dry friction conditions. Before and after tribological test, examination of the geometrical structure of counter-specimens' surface was carried out using the Form Talysurf contact profilographometer, via a 3D method. The most satisfactory tribological parameters were obtained for the PEEK/BG association with the coating produced at a distance between the electrodes equal to 0.25 m.
doi:10.2478/cqpi-2019-0054 fatcat:ytyxss5hsvfi7jq7uvdbtrhgs4

Problems in the Implementation of the Lean Concept at a Steel Works - Case Study

Adrian Maszke, Renata Dwornicka, Robert Ulewicz, R. Ulewicz, B. Hadzima
2018 MATEC Web of Conferences  
The paper presents the experience of implementing selected instruments of the Lean concept at a steel works. The functioning of an enterprises in the currently prevailing conditions, i.e. in a turbulent environment, results in increased customer requirements. They expect, among other things, high quality of steel products delivered on time at a low price. Many organizations decide to implement the lean management concept without proper preparation. The purpose of this paper is to present the
more » ... itations occurring during the implementation of the lean management concept in a steel mill.
doi:10.1051/matecconf/201818301014 fatcat:z3q2dbfetncx7fum6ag6mrqcnm

Exploitation Characteristics of Teeth Flanks of Gears Regenerated by Three Hard-Facing Procedures

Svetislav Marković, Dušan Arsić, Ružica R. Nikolić, Vukić Lazić, Branislav Hadzima, Vladimir P. Milovanović, Renata Dwornicka, Robert Ulewicz
2021 Materials  
Numerous phenomena that occur during the process of machine parts' regeneration have a significant impact on the loss of their working ability. Therefore, the properties of the working surfaces of the teeth flanks of repaired gears were analyzed in this research. The hereditary properties of the gear teeth are expressed by the interdependence of their geometric and physical-mechanical-metallurgical parameters created during the technological operations of regeneration of worn teeth by
more » ... rd-facing. The hard-facing was executed with three filler metal types, namely: combination Inox 18/8/6 + EDur 600, Castolin 2 and UTP 670. The tested properties included geometrical accuracy, microstructure and microhardness. Evaluation of the executed regeneration procedures was done by comparing the mentioned parameters of the regenerated gears and the new ones. The tested gears were not withdrawn from production due to damage, but they were newly manufactured and intentionally damaged gears, made of the same materials, subjected to the same manufacturing process. In this way, all influences except for the considered filler metal type were eliminated. Based on results of the conducted experiments, it was possible to establish the influence of the filler metal type on the surface characteristics of the regenerated gears' teeth flanks.
doi:10.3390/ma14154203 fatcat:zkphppnrxjdkldkdcprce3zxjq

Quality Analysis of the Mechanical Lever and Improvement of Non-Destructive Testing Process

Dominika Siwiec, Andrzej Pacana, Renata Dwornicka
2020 System Safety: Human - Technical Facility - Environment  
AbstractThe analysis of product quality is an indispensable action in developing enterprises. In case of mechanical products, the non-destructive tests (NDT) are effective way to make control. Non-destructive tests allow making assessing product quality without destroying it. Due to the dynamically growing requirements of customers and necessary, the improvement actions for demanding organizations important is to make a complex analysis of quality products. Such an action was proposed to a
more » ... ction and service company located in Podkarpacie region of Poland. The aim was to analyze the quality of the mechanical lever and improvement the process of non-destructive tests, in order to identify the source of nonconformity with using quality management techniques. These activities were to demonstrate that the sequence (NDT and selected quality management techniques) would allow the detection of unconformities on the product surface and also identify the source of this unconformity. In the enterprise, the quality research of the product using fluorescent and magnetic-powder methods was made. After identified the unconformity on the product the additional actions which could point the source of unconformity were not practicing. The proposition of improvement in the NTD was use appropriately selected quality management techniques (Ishikawa diagram and 5Why method) after identified the unconformity. The mechanical lever was tested, which its surface using the magnetic-powder method was analyzed. After identified unconformity (scratch) using the Ishikawa diagram, the potential causes were identified and four main causes were selected (i.e.: uncleaned pattern, impurities during production, poor molding mass, poorly carried out product production method). It has been shown that sequence of NDT, Ishikawa diagram and 5Why method allows to identify the unconformity on product surface and source its creation. This sequence could be practicing to analyze other product in production and services enterprises.
doi:10.2478/czoto-2020-0037 fatcat:z7qr6tgecnaudifwsv5n4xxrv4

The analysis of friction properties after laser texturizing of the silicon carbide surface layer

Norbert Radek, Agnieszka Szczotok, Renata Dwornicka, R. Ulewicz, B. Hadzima
2018 MATEC Web of Conferences  
The modification of the surface properties is a desired technological procedure. One of the possible method is the electro-spark deposition (ESD). Unfortunately, ESD process produces a surface with high roughness. The laser beam machining (LBM) has been involved to lower roughness of the coating made by ESD. The elements coated by ESD have been tested to determine tribological properties and they were compared before and after LBM. To achieve high reliability of the results, the test has been
more » ... nducted in accordance with design of experiments methodology and the results which were obtained have been processed by a statistical analysis. The description of such an experiment performed for a silicon carbide SiC coating, the obtained results and the conclusions are included in this paper.
doi:10.1051/matecconf/201818302010 fatcat:i7z4fqdydnc47fjcm2zsf567ju


Renata, Dominik, Marek Iwaniec
The studies of the Biomedical Engineering faculty combine technical and humanistic elements. The biomedical engineering itself is a combination of knowledge located at the intersection of engineering, medical and biological applications. Technical universities which offer training courses on Biomedical Engineering place greater emphasis on engineering education. It is apparent, however, that the majority of students of this course are graduates of high schools with humanistic knowledge and no
more » ... chnical preparation. Initial teaching of technical subjects must therefore be conducted in a language and format accessible to the "non-engineers". Particularly, it is important to demonstrate and teach students the tools that will facilitate their further education.


Robert ULEWICZ, Frantisek NOVY, Renata DWORNICKA
2020 METAL 2020 Conference Proeedings   unpublished
Metal foundry, despite the progressing process of implementing new production technologies -still belongs to the fields characterized by a significant level of occupational risk. In metal foundries there is a significant concentration of harmful and arduous factors at many workplaces. The degree of work safety depends, among others, on the technology, raw materials and technical equipment used. The paper presents an analysis of the accident rate based on statistical data extended by own
more » ... and results obtained from the conducted expert interview. Based on the results obtained, the most important factors harmful to health were defined and an analysis of the causes of accidents at work in foundries was carried out. Ensuring adequate in terms of quality and safety is an important element of the management process not only in the purely human dimension but also in the economic dimension.
doi:10.37904/metal.2020.3649 fatcat:6fomcnq6rjel7lhmd6wjswlble
« Previous Showing results 1 — 15 out of 24 results