Browsing by Subject "statistical methods"

Now showing 1 - 9 of 9

Access status: Open Access ,
Assessment of statistical stability of steel strip hot-rolling process
(2008) Czarski, Andrzej
Statistical methods belong to the basic quality tools. Among statistical instruments the statistical process control SPC takes particular place. One of the principal tasks of SPC is monitoring of a process by means of control charts. They are first of all Shewhart's control charts. The aim of investigations was to assess stability of technological process of hot-rolling of steel strip. There were available the results of thickness measurements madę with an X-ray thickness gauge as well as measurements of convexity and wedge shape made with a profile measurement gauge. The assessment of statistical process stability was performed by means of Shewarfs control charts technique. In case of thickness the estimation of capability indices Cp, Cpk and Pp, Ppk have been carried out, in addition.
Access status: Open Access ,
Capability process assessment in Six Sigma approach
(2007) Czarski, Andrzej
Statistical techniques occupy a particular place in the organizational culture Six Sigma that is used in many renowned organizations (Motorola, General Electric, Bombardier, Nokia, Sony, BMW, Philips etc.) in order to achieve in the shortest possible time the highest quality level. In the Six Sigma approach the assessment of a process potential is made relating to client's expectations using long-term and short-term process capability - correspondingly Cp, Cpk and Pp, Ppk. The basis of such an assessment of process capability is partition of the total process variability into two components: the component independent on time (the same material, operator, tools and process setting) and the component dependent on time (caused by e.g. changes oí raw material, process setting etc.). Such a partition oí the variability is necessary, it enables the better understanding of the process and in consequence - its improvement. The aim of research has been the assessment of short-term and long-term capability of the process of drop forgings heat treatment regarding the hardness. The estimation of capability indices Cp, Cpk and Pp, Ppk as well as the detailed interpretation of the results have been carried out.
Access status: Open Access ,
Comparing deterministic and statistical approaches for predicting »short can« defects in aluminium beverage can production
(Wydawnictwa AGH, 2023) Baran, Wojciech; Regulski, Krzysztof; Kąc, Sławomir; Milenin, Andriy
In the production of beverage cans, »short can« defects in the form of material discontinuities can occur during the deep drawing of cylindrical thin-walled aluminium products. These defects have a significant impact on production efficiency and scrap generation, and their occurrence is influenced by material and process properties. To determine the main influence of material on defect occurrence, two approaches were used: deterministic analysis of mechanical properties and microstructure, as well as statistical processing of production data using decision tree models. The latter approach was found to be more efficient, and a numerical tool was developed based on this approach to predict and reduce defect occurrence in the production process.
Access status: Open Access ,
Computational challenges in the measurement of heavy-ion collision event characteristics with the atlas experiment at the LHC
(Wydawnictwa AGH, 2015) Maj, Klaudia; Bołd, Tomasz; Grabowska-Bołd, Iwona
Heavy-ion collisions at extreme energies are expected to recreate conditions present in the early universe, producing a state of matter called the Quark Gluon Plasma (QGP). This state is characterized by very low viscosity resembling the properties of a perfect fluid. In such a medium, density fluctuations can easily propagate. In experimental practice, the size of these fluctuations is estimated by measuring the angular correlation of the particles produced. The aim of this paper is to present results of the measurements of the azimuthal anisotropy of charged particles produced in heavy-ion collisions with the ATLAS detector using the LHC Grid infrastructure for bulk processing of the data and resources available at the Tier-2 computing center for the final analysis stage.
Access status: Restricted ,
Geostatystyka : teoria i zastosowania
(Oficyna Wydawnicza Politechniki Wrocławskiej, 2006) Namysłowska-Wilczyńska, Barbara
Access status: Open Access ,
Influence of measurement system quality on the evaluation of process capability indices
(2012) Czarski, Andrzej; Matusiewicz, Piotr
Among statistical instruments of quality Statistical Process Control (SPC) and Measurement Systems Analysis (MSA) take particular place. The proper quality of measurement data - verification and assurance of this quality are the task of MSA - guarantees an opportunity to carry out a solid SPC analysis supplying information about a process behavior. One of the principal tasks of SPC is estimation of capability of a process i.e. the assessment of process potential as for variability regarding expectations defined by specification limits. Data for analysis of a process capability are the results of measurements made by means of a determined measurement system. The variability of this measurement system must influence the results of capability assessment, however the measurement system adequate to control the process should guarantee that the impact is little enough to be omitted. The subject of the work is the analysis of influence of measurement system variability on evaluation of process capability indices. The mutual relations between process variability and measurement system variability present analytical relationships and experimental research given in the work. The aim of the tests was an assessment of a capability of the process of steel drop forgings' heat treatment relating to a hardness. The methodology demonstrated in the work is valid quality standards compatible (ISO 9000, ISO/TS 16949 etc.).
Access status: Open Access ,
Modelling of urban estates' values
(2011) Parzych, Piotr
The urban estates are particular components of ground property. The urban estates are characterized by the ground components of great complication. Urbanized estates may be of following type: urban grounds, commercial premises, office buildings, welfare buildings, industrial buildings, warehouse buildings and small buildings of some type. Transactions including urban estates are not very common at the real estates' market. However, if a transaction takes place, all components of the estate have an influence on the transaction price. The application of such transaction prices for the valuation of similar estates is very complicated, for estates' components structure is highly differentiated and it is not possible to establish estates' representative reference unit. The algorithm enabling the sold industrial estates unit element's and transaction prices comparative analysis with elements of valuated urban estates will be presented in this paper. This algorithm is based on statistical modelling. Its result is the urban estates' market value estimation.
Access status: Open Access ,
Statistical methods in quality management - process capability analysis
(2007) Czarski, Andrzej; Satora, Kazimierz; Matusiewicz, Piotr
Statistical methods belong to the basic quality tools. Among statistical instruments the statistical process control SPC takes particular place. One of the principal tasks of SPC is process capability analysis i.e. the assessment of process potential as for variability regarding expectations defined by specification limits. For capability estimation some indices are used - Cp, Cpk, Pp, Ppk etc. In this work the way of determining and interpreting capability indices Cp, Cpk of so-called first generation in relation to the process of steel forgings production has been presented.
Access status: Open Access ,
Zastosowanie wielowymiarowych metod statystycznych w geologicznej interpretacji profilowań geofizyki otworowej dla mioceńskich utworów z rejonu złoża Księżpol
(Wydawnictwa AGH, 2009) Kaźmierczuk, Monika; Jarzyna, Jadwiga
The Miocene formation in the area of Księżpol gas field is built of very thin sandy-shaly layers. Log data from wells Księżpol 11 and Księżpol 17 were processed with statistical methods. Principal Component Analysis was used for grouping and specifying well log data. Clustering, discrimination and classification are statistical tools facilitating data arrangement and preliminary data grouping according to natural petrophysical features of analysed rocks.