• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 2
  • 1
  • Tagged with
  • 8
  • 8
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

GLR Control Charts for Process Monitoring with Sequential Sampling

Peng, Yiming 06 November 2014 (has links)
The objective of this dissertation is to investigate GLR control charts based on a sequential sampling scheme (SS GLR charts). Phase II monitoring is considered and the goal is to quickly detect a wide range of changes in the univariate normal process mean parameter and/or the variance parameter. The performance of the SS GLR charts is evaluated and design guidelines for SS GLR charts are provided so that practitioners can easily apply the SS GLR charts in applications. More specifically, the structure of this dissertation is as follows: We first develop a two-sided SS GLR chart for monitoring the mean μ of a normal process. The performance of the SS GLR chart is evaluated and compared with other control charts. The SS GLR chart has much better performance than that of the fixed sampling rate GLR chart. It is also shown that the overall performance of the SS GLR chart is better than that of the variable sampling interval (VSI) GLR chart and the variable sampling rate (VSR) CUSUM chart. The SS GLR chart has the additional advantage that it requires fewer parameters to be specified than other VSR charts. The optimal parameter choices are given, and regression equations are provided to find the limits for the SS GLR chart. If detecting one-sided shifts in μ is of interest, the above SS GLR chart can be modified to be a one-sided chart. The performance of this modified SS GLR chart is investigated. Next we develop an SS GLR chart for simultaneously monitoring the mean μ and the variance 𝜎² of a normal process. The performance and properties of this chart are evaluated. The design methodology and some illustrative examples are provided so that the SS GLR chart can be easily used in applications. The optimal parameter choices are given, and the performance of the SS GLR chart remains very good as long as the parameter choices are not too far away from the optimized choices. / Ph. D.
2

Controlling High Quality Manufacturing Processes: A Robustness Study Of The Lower-sided Tbe Ewma Procedure

Pehlivan, Canan 01 September 2008 (has links) (PDF)
In quality control applications, Time-Between-Events (TBE) type observations may be monitored by using Exponentially Weighted Moving Average (EWMA) control charts. A widely accepted model for the TBE processes is the exponential distribution, and hence TBE EWMA charts are designed under this assumption. Nevertheless, practical applications do not always conform to the theory and it is common that the observations do not fit the exponential model. Therefore, control charts that are robust to departures from the assumed distribution are desirable in practice. In this thesis, robustness of the lower-sided TBE EWMA charts to the assumption of exponentially distributed observations has been investigated. Weibull and lognormal distributions are considered in order to represent the departures from the assumed exponential model and Markov Chain approach is utilized for evaluating the performance of the chart. By analyzing the performance results, design settings are suggested in order to achieve robust lower-sided TBE EWMA charts.
3

Rozbor parametrů výrobních zakázek ve společnosti NATE - nápojová technicka a. s. za období 2002 - 2012 / An analysis of the production parameters of the products of a company NATE-nápojová technika a.s. for the period 2002-2012

Klepetková, Iva January 2012 (has links)
This thesis deals with an analysis of the production parameters of the two main products of a company NATE-nápojová technika a.s. for the period 2002-2012. Based on the theoretical fundamentals of production management and purchasing process. It analyzes each product from the customer's territory, production deadlines, cost and productivity. Based on this analysis are revealed weak points in the production and the purchase process and try to find ways to resolve them.
4

Optimalizace vybraných návrhových prvků ČSN pro projektování místních komunikací / Optimization Of Selected Proposed ČSN Elements For Urban Road Design

Šilar, Daniel January 2014 (has links)
The purpose of this diploma thesis „Optimization Of Selected Proposed ČSN Elements For Urban Road Design„ is car parks at shopping centers. Goal of this thesis is to compare calculation parameters for car parks according to Czech standards for design of local communication with standards in selected countries in the world. Another goal of this work is to fill in missing information for assessment of capacity of connections to ground communication for various types of shopping centers. Second part of the work is focused on the measurement itself and data analysis. The last part of the work consists of comparison of calculated parking places according to standards with real number of parking places.
5

The Design of GLR Control Charts for Process Monitoring

Xu, Liaosa 27 February 2013 (has links)
Generalized likelihood ratio (GLR) control charts are investigated for two types of statistical process monitoring (SPC) problems. The first part of this dissertation considers the problem of monitoring a normally distributed process variable when a special cause may produce a time varying linear drift in the mean. The design and application of a GLR control chart for drift detection is investigated. The GLR drift chart does not require specification of any tuning parameters by the practitioner, and has the advantage that, at the time of the signal, estimates of both the change point and the drift rate are immediately available. An equation is provided to accurately approximate the control limit. The performance of the GLR drift chart is compared to other control charts such as a standard CUSUM chart and a CUSCORE chart designed for drift detection. We also compare the GLR chart designed for drift detection to the GLR chart designed for sustained shift detection since both of them require only a control limit to be specified. In terms of the expected time for detection and in terms of the bias and mean squared error of the change-point estimators, the GLR drift chart has better performance for a wide range of drift rates relative to the GLR shift chart when the out-of-control process is truly a linear drift. The second part of the dissertation considers the problem of monitoring a linear functional relationship between a response variable and one or more explanatory variables (a linear profile). The design and application of GLR control charts for this problem are investigated. The likelihood ratio test of the GLR chart is generalized over the regression coefficients, the variance of the error term, and the possible change-point. The performance of the GLR chart is compared to various existing control charts. We show that the overall performance of the GLR chart is much better than other options in detecting a wide range of shift sizes. The existing control charts designed for certain shifts that may be of particular interest have several chart parameters that need to be specified by the user, which makes the design of such control charts more difficult. The GLR chart is very simple to design, as it is invariant to the choice of design matrix and the values of in-control parameters. Therefore there is only one design parameter (the control limit) that needs to be specified. Especially, the GLR chart can be constructed based on the sample size of n=1 at each sampling point, whereas other charts cannot be applied. Another advantage of the GLR chart is its built-in diagnostic aids that provide estimates of both the change-point and the values of linear profile parameters. / Ph. D.
6

Incremento de la producción de cuadernos a partir de la implementación del RCM en la Gestión de Mantenimiento / Increase in the production of notebooks from the implementation of the RCM in Maintenance Management

Paredes Nateros, Javier Glenne, Tupez Mendoza, Jhon Rogger 05 September 2019 (has links)
Dentro del contenido de este documento se desarrolla una propuesta para incrementar la producción de cuadernos en la línea R17de la empresa Panasa, aplicando la metodología RCM. En el capítulo 1 se presenta una revisión bibliográfica de los temas principales sobre los que se fundamenta la propuesta de mejora: el sector papelero en el Perú, la evolución del mantenimiento, definición de términos, tipos de mantenimiento, técnicas de mantenimiento avanzado (RCM, TPM), costos de mantenimiento, indicadores, herramientas de mejora continua y casos de éxitos en la implementación del RCM. En el capítulo 2 se realiza una descripción general de la empresa (reseña histórica, misión, visión, valores, organigrama, productos, clientes, ventas y el proceso productivo) para finalmente llegar al detalle de la situación actual. Luego se describe y cuantifica el principal problema que afecta al cumplimiento del plan de producción anual, posteriormente se hace el análisis de causa raíz para identificar las principales causas que están generando el problema. En el capítulo 3 se evalúa tres posibles soluciones para el problema (RCM, TPM, CBM), para la elección de la metodología a aplicar se hace uso del ranking de factores y se desarrolla cada una de las fases del RCM. En el capítulo 4 se valida la propuesta para lo cual se hace un modelamiento del proceso actual y propuesto utilizando el Software de simulación ARENA, también se hace una evaluación económica-financiera para determinar la viabilidad del proyecto. El cierre de la tesis se da mediante la presentación de las conclusiones y recomendaciones. / This document develops a proposal to increase the production of notebooks in the R17 line of the Panasa company, applying the RCM methodology. Chapter 1 presents a bibliographic review of the main topics on which the proposal for improvement is based: the paper industry in Peru, the evolution of maintenance, definition of terms, types of maintenance, advanced maintenance techniques (RCM, TPM), maintenance costs, indicators, continuous improvement tools and success stories in the implementation of the RCM. In Chapter 2 a general description of the company (historical review, mission, vision, values, organization chart, products, customers, sales and the production process) is made to finally get to the detail of the current situation. Then the main problem that affects the fulfillment of the annual production plan is described and quantified, then the root cause analysis is done to identify the main causes that are generating the problem. Chapter 3 evaluates three possible solutions to the problem (RCM, TPM, CBM), for the choice of the methodology to be applied, the ranking of factors is used and each phase of the RCM is developed. Chapter 4 validates the proposal for which a modeling of the current and proposed process is done using the ARENA simulation software, an economic-financial evaluation is also made to determine the viability of the project. The thesis is closed by presenting the conclusions and recommendations. / Tesis
7

GLR Control Charts for Monitoring Correlated Binary Processes

Wang, Ning 27 December 2013 (has links)
When monitoring a binary process proportion p, it is usually assumed that the binary observations are independent. However, it is very common that the observations are correlated with p being the correlation between two successive observations. The first part of this research investigates the problem of monitoring p when the binary observations follow a first-order two-state Markov chain model with p remaining unchanged. A Markov Binary GLR (MBGLR) chart with an upper bound on the estimate of p is proposed to monitor a continuous stream of autocorrelated binary observations treating each observation as a sample of size n=1. The MBGLR chart with a large upper bound has good overall performance over a wide range of shifts. The MBGLR chart is optimized using the extra number of defectives (END) over a range of upper bounds for the MLE of p. The numerical results show that the optimized MBGLR chart has a smaller END than the optimized Markov binary CUSUM. The second part of this research develops a CUSUM-pp chart and a GLR-pp chart to monitor p and p simultaneously. The CUSUM-pp with two tuning parameters is designed to detect shifts in p and p when the shifted values are known. We apply two CUSUM-pp charts as a chart combination to detect increases in p and increases or decreases in p. The GLR-pp chart with an upper bound on the estimate of p, and an upper bound and a lower bound on the estimate of p works well when the shifts are unknown. We find that the GLR-pp chart has better overall performance. The last part of this research investigates the problem of monitoring p with p remains at the target value when the correlated binary observations are aggregated into samples with n>1. We assume that samples are independent and there is correlation between the observations in a sample. We proposed some GLR and CUSUM charts to monitor p and the performance of the charts are compared. The simulation results show MBNGLR has overall better performance than the other charts. / Ph. D.
8

Average case analysis of algorithms for the maximum subarray problem

Bashar, Mohammad Ehsanul January 2007 (has links)
Maximum Subarray Problem (MSP) is to find the consecutive array portion that maximizes the sum of array elements in it. The goal is to locate the most useful and informative array segment that associates two parameters involved in data in a 2D array. It's an efficient data mining method which gives us an accurate pattern or trend of data with respect to some associated parameters. Distance Matrix Multiplication (DMM) is at the core of MSP. Also DMM and MSP have the worst-case complexity of the same order. So if we improve the algorithm for DMM that would also trigger the improvement of MSP. The complexity of Conventional DMM is O(n³). In the average case, All Pairs Shortest Path (APSP) Problem can be modified as a fast engine for DMM and can be solved in O(n² log n) expected time. Using this result, MSP can be solved in O(n² log² n) expected time. MSP can be extended to K-MSP. To incorporate DMM into K-MSP, DMM needs to be extended to K-DMM as well. In this research we show how DMM can be extended to K-DMM using K-Tuple Approach to solve K-MSP in O(Kn² log² n log K) time complexity when K ≤ n/log n. We also present Tournament Approach which solves K-MSP in O(n² log² n + Kn²) time complexity and outperforms the K-Tuple

Page generated in 0.0617 seconds