The X-bar control chart with restriction of the capability indices

2017 ◽  
Vol 34 (1) ◽  
pp. 38-52 ◽  
Author(s):  
Pedro Carlos Oprime ◽  
Glauco Henrique de Sousa Mendes
Keyword(s):  
Phase I ◽  
Control Chart ◽  
Design Methodology ◽  
Simulation Method ◽  
Operating Conditions ◽  
Suggested Approach ◽  
Content Type ◽  
Capability Index ◽  
Simulation Techniques ◽  
Capability Indices

Purpose The purpose of this paper is to find the configuration of the number (m) and size (n) of the sample in Phase I that would make it possible to detect the out-of-control (OOC) state of the process with the smallest number of samples and ensure a capability index (Cpk) that would meet the customer’s requirements. Design/methodology/approach The suggested approach addresses this problem using simulation techniques and design of experiments (DOE). The simulation techniques made it possible to reproduce the normal operating conditions of the process. The DOE was used to construct a predictive model for control chart performance and thus to determine combinations of m and n in Phase I that would meet the capability objectives of the process. A numerical example and a simulation study were conducted to illustrate the proposed method. Findings Using simulation techniques and DOE, the authors can find the number (m) and size (n) of the sample in Phase I that would make it possible to detect the OOC state of the process with the smallest number of samples and ensure a Cpk that would meet the customer’s requirements. Originality/value In the real situations of many companies, choosing the numbers and sizes of samples (m and n) in Phases I and II is a crucial decision in relation to implementing a control chart. The paper shows that the simulation method and use of linear regression are effective alternatives because they are better known and more easily applied in industrial settings. Therefore, the need for alternatives to the X control chart comes into play.

Prediction of clothing mobility using a musculoskeletal simulator

2019 ◽  
Vol 32 (1) ◽  
pp. 132-147
Author(s):  
Yosuke Horiba ◽  
Ayumu Tokutake ◽  
S. Inui
Keyword(s):  
Human Body ◽  
Design Methodology ◽  
Elbow Flexion ◽  
Simulation Method ◽  
Musculoskeletal Model ◽  
Joint Torque ◽  
Musculoskeletal Simulation ◽  
Content Type ◽  
Clothing Design ◽  
Dressed State

Purpose Mobility is one of the important elements in clothing design. The purpose of this paper is to examine the predictability of clothing mobility via musculoskeletal simulation. Design/methodology/approach In order to carry out the musculoskeletal simulation considering the influence of clothing, simulation of the dressed state was attempted. This paper simulated the dressed state and measured the motion-related deformation of the clothing to estimate the force applied to the human body based on the material property of the clothing samples. The dressed state was simulated using an external force in the musculoskeletal model. Findings When the elbow flexion torque with an elbow supporter was calculated using the above-mentioned method of musculoskeletal simulation, it was confirmed that the lower the stretchability of the sample, the higher the elbow flexion torque. In addition, the sensory evaluation performed under the same condition as that in the simulation showed that the lower the joint torque during the motion, the higher the subjective mobility, and that the higher the joint torque, the lower the subjective mobility. Thus, it is suggested that musculoskeletal simulation of the dressed state can predict the clothing mobility. Research limitations/implications However, the method proposed in this paper requires the measurement of the deformation of the clothing to estimate the force applied to the human body. Thus, it is difficult to apply this in the measurement of general clothing that allows enough space between it and the human body, requiring further improvement of the dressed state simulation method. Originality/value Because it is difficult to estimate the force applied by the clothing to the human body, only a few studies have performed analysis on the effect of clothing by using musculoskeletal simulation. Conversely, although the force applied by the clothing to the human body needs to be estimated in advance by the measurement of the deformation, the utility of the simulation in clothing design seems to be high because the simulation can estimate clothing mobility and the effects of clothing on muscle activity.

Numerical simulations of non-stationary distributions of electrochemical potentials in SOFC

2017 ◽  
Vol 34 (6) ◽  
pp. 1956-1988 ◽  
Author(s):  
Mayu Muramatsu ◽  
Keiji Yashiro ◽  
Tatsuya Kawada ◽  
Kenjiro Tarada
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Chemical Potential ◽  
Simulation Method ◽  
Open Circuit ◽  
Operating Conditions ◽  
Stationary Distributions ◽  
Experimental Conditions ◽  
Content Type ◽  
Numerical Examples

Purpose The purpose of this study is to develop a simulation method to calculate non-stationary distributions of the chemical potential of oxygen in a solid oxide fuel cell (SOFC) under operation. Design/methodology/approach The initial-boundary value problem was appropriately formulated and the appropriate boundary conditions were implemented so that the problem of non-stationary behavior of SOFC can be solved in accordance with actual operational and typical experimental conditions. The dependencies of the material properties on the temperature and partial pressure of oxygen were also elaborately introduced to realize actual material responses. The capability of the proposed simulation method was demonstrated under arbitrary operating conditions. Findings The steady state calculated with the open circuit voltage condition was conformable with the analytical solution. In addition, the transient states of the spatial distributions of potentials and currents under the voltage- and current-controlled conditions were successfully differentiated, even though they eventually became the same steady state. Furthermore, the effects of dense materials assumed for interconnects and current collectors were found to not be influential. It is thus safe to conclude that the proposed method enables us to simulate any type of transient simulations regardless of controlling conditions. Practical implications Although only uniaxial models were tested in the numerical examples in this paper, the proposed method is applicable for arbitrary shapes of SOFC cells. Originality/value The value of this paper is that adequate numerical simulations by the proposed method properly captured the electrochemical transient transport phenomena in SOFC under various operational conditions, and that the applicability was confirmed by some numerical examples.

Numerical simulation of Nusselt-Rayleigh correlation in Bénard cells. A solution based on the network simulation method

2015 ◽  
Vol 25 (5) ◽  
pp. 986-997 ◽  
Author(s):  
Manuel Cánovas ◽  
Iván Alhama ◽  
Emilio Trigueros ◽  
Francisco Alhama
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Porous Media ◽  
Design Methodology ◽  
Network Simulation ◽  
Simulation Method ◽  
Extensive Study ◽  
Dimensionless Number ◽  
Content Type ◽  
Network Simulation Method

Purpose – Natural convection with heat transfer in porous media has been subject of extensive study in engineering due to its numerous applications. A case of particular interest is the Bénard-type flow.The paper aims to discuss this issue. Design/methodology/approach – Based on the network simulation method in order to solve this problem, a numerical model is proposed. Findings – Nusselt-Rayleigh correlation is determined for a broad range of Rayleigh, the dimensionless number that influences the solution, above and below the threshold which separates the conduction and convection pure mechanisms. Originality/value – Based on the network simulation method.

Robust approaches for monitoring logistic regression profiles under outliers

2017 ◽  
Vol 34 (4) ◽  
pp. 494-507 ◽  
Author(s):  
Ahmad Hakimi ◽  
Amirhossein Amiri ◽  
Reza Kamranrad
Keyword(s):  
Logistic Regression ◽  
Robust Control ◽  
Phase I ◽  
Control Chart ◽  
Phase Ii ◽  
Control Charts ◽  
Likelihood Estimation ◽  
Estimation Of Parameters ◽  
Content Type ◽  
Practical Applications

Purpose The purpose of this paper is to develop some robust approaches to estimate the logistic regression profile parameters in order to decrease the effects of outliers on the performance of T2 control chart. In addition, the performance of the non-robust and the proposed robust control charts is evaluated in Phase II. Design/methodology/approach In this paper some, robust approaches including weighted maximum likelihood estimation, redescending M-estimator and a combination of these two approaches (WRM) are used to decrease the effects of outliers on estimating the logistic regression parameters as well as the performance of the T2 control chart. Findings The results of the simulation studies in both Phases I and II show the better performance of the proposed robust control charts rather than the non-robust control chart for estimating the logistic regression profile parameters and monitoring the logistic regression profiles. Practical implications In many practical applications, there are outliers in processes which may affect the estimation of parameters in Phase I and as a result of deteriorate the statistical performance of control charts in Phase II. The methods developed in this paper are effective for decreasing the effect of outliers in both Phases I and II. Originality/value This paper considers monitoring the logistic regression profile in Phase I under the presence of outliers. Also, three robust approaches are developed to decrease the effects of outliers on the parameter estimation and monitoring the logistic regression profiles in both Phases I and II.

Effects of operating conditions on cavitation induction of spiral groove liquid-film seal (SG-LFS)

2020 ◽  
Vol 72 (10) ◽  
pp. 1267-1275
Author(s):  
Zhentao Li ◽  
Xiaoli Yin ◽  
Jixiang Yue ◽  
Fuyu Liu ◽  
Muming Hao ◽  
...  
Keyword(s):  
Liquid Film ◽  
Relative Density ◽  
Peer Review ◽  
Design Methodology ◽  
Operating Conditions ◽  
Spiral Groove ◽  
Content Type ◽  
Relaxation Scheme ◽  
Cavitation Pressure ◽  
Lubricant Viscosity

Purpose The purpose of this paper is to study the effects of operating conditions including process coefficient, lubricant viscosity and cavitation pressure on the cavitation of spiral groove liquid-film seal (SG-LFS). Design/methodology/approach A mathematical model of SG-LFS is established based on the JFO boundary and a relative density is introduced. The universal governing equation after a coordinate transformation is discretized by the FVM method and solved by the Gauss-Seidel relaxation scheme. Findings The results indicate that the two-dimensional size of cavitation and cavitation degree are affected significantly by the process coefficient and lubricant viscosity but the effect of cavitation pressure can be ignored. Originality/value The effect mechanisms of operating conditions on the cavitation of SG-LFS are studied by the JFO boundary and cavitation degree characterized by a relative density. The results presented are helpful to perfect and deeply understand the cavitation mechanism of liquid-film seal. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0083/

FDGM(1,1) model based on unified fractional grey generation operator

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Meng ◽  
Qian Li ◽  
Bo Zeng ◽  
Yingjie Yang
Keyword(s):  
Design Methodology ◽  
Simulation Method ◽  
Simple Expression ◽  
Fractional Operators ◽  
Modeling Error ◽  
Content Type ◽  
New Information ◽  
The Relationship ◽  
Special Case ◽  
Practical Implications

PurposeThe purpose of this paper is to unify the expression of fractional grey accumulating generation operator and the reducing generation operator, and build the FDGM(1,1) model with the unified fractional grey generation operator.Design/methodology/approachBy systematically studying the properties of the fractional accumulating operator and the reducing operator, and analyzing the sensitivity of the order value, a unified expression of the fractional operators is given. The FDGM(1,1) model with the unified fractional grey generation operator is established. The relationship between the order value and the modeling error distribution is studied.FindingsThe expression of the fractional accumulating generation operator and the reducing generation operator can be unified to a simple expression. For −1<r < 1, the fractional grey generation operator satisfies the principle of new information priority. The DGM(1,1) model is a special case of the FDGM(1,1) model with r = 1.Research limitations/implicationsThe sensitivity of the unified operator is verified through random numerical simulation method, and the theoretical proof was not yet possible.Practical implicationsThe FDGM(1,1) model has a higher modeling accuracy and modeling adaptability than the DGM(1,1) by optimizing the order.Originality/valueThe expression of the fractional accumulating generation operator and the reducing generation operator is firstly unified. The FDGM(1,1) model with the unified fractional grey generation operator is firstly established. The unification of the fractional accumulating operator and the reducing operator improved the theoretical basis of grey generation operator.

Partial centralization in three-division organizations

2014 ◽  
Vol 5 (2) ◽  
pp. 187-210
Author(s):  
Siguang Li ◽  
Xi Weng
Keyword(s):  
Organizational Performance ◽  
Information Structure ◽  
Design Methodology ◽  
Optimal Allocation ◽  
Simulation Analysis ◽  
Organizational Structures ◽  
Governance Structure ◽  
Operating Conditions ◽  
Information Structures ◽  
Content Type

Purpose – The purpose of this paper is to investigate the optimal allocation of authority within “chain” organizations and to show when partial centralization becomes dominant in the sense of organizational performance. Design/methodology/approach – This paper takes an incomplete contract approach and uses an information transmission framework to investigate the optimal governance structure, in which non-contractible decisions must be adapted to local operating conditions, and also coordinated with the upstream and downstream divisions. We also use simulation analysis to numerically show the theoretical mapping between the underlying parameters (i.e. coordination need) and the dominant organizational structures. Findings – Partial decentralization will arise as the optimal governance structure only when the information in the middle branch is relatively concentrated or dispersive, so as to exploit the underlying information structure in the “chain” organizations. Specifically, when information is highly concentrated, direct control of the middle branch can improve coordination within firms. When the information is highly dispersive, to delegate authority to the middle branch only can improve communication. Originality/value – This paper characterizes the optimal governance structure in “chain” organizations. The findings may give some enlightenment on real authority driven by ex ante asymmetric information structures and have implications on asymmetric delegation within firms.

Economic design of x-bar control chart under hybrid maintenance policy

2018 ◽  
Vol 24 (3) ◽  
pp. 331-344
Author(s):  
Xiaomei Yang ◽  
Jianchao Zeng
Keyword(s):  
Product Quality ◽  
Control Chart ◽  
Design Methodology ◽  
Maintenance Policy ◽  
Product Quality Control ◽  
Statistical Process ◽  
Content Type ◽  
Machine Maintenance ◽  
Monitoring Result ◽  
Degradation State

Purpose According to the relevance of product quality and machine degradation state, a hybrid maintenance policy is designed. The paper aims to discuss this issue. Design/methodology/approach Product quality control and machine maintenance are considered simultaneously in this policy. Based on this policy, the economic model of x-bar control chart is proposed using statistical process control and renewal reward theory. Findings This model is solved by genetic algorithm and the experimental results validated its feasibility. Originality/value In this model, the four corresponding relationship, which is between product quality monitoring result and machine degradation state, is analyzed.

Modeling and optimization of sand crushing plant using experimental design methodology

2019 ◽  
Vol 16 (4) ◽  
pp. 487-496
Author(s):  
Djamel Benyessad ◽  
Hamid Arkoub ◽  
Abdelghani Seghir
Keyword(s):  
Mathematical Model ◽  
Experimental Design ◽  
Design Methodology ◽  
Operating Conditions ◽  
Experimental Program ◽  
Operating Parameters ◽  
Content Type ◽  
Modeling And Optimization ◽  
Crushing Plant

Purpose The purpose of this paper is to present results of an experimental program conducted on manufacturing process of crushed sand. The aim of the research is to propose an optimized approach which allows to fix, directly at the process stage, the rate of fines in the produced crushed sand. Design/methodology/approach In the first step of the study, samples of crushed sand are collected in situ, at each adjustment of the identified operating parameters. They are then analyzed in laboratory to retrieve especially the fines contents for each adjustment. These adjustments are conducted for all possible combinations of the extremum operating conditions of the parameters. In the second step of the study, the experimental design technique is applied to study the influence of the different factors, and to model the interaction between them. An expression is obtained and subjected to statistical tests, and then it is confronted to other experimental measures. Findings Parameters influencing the fines rates are identified and their effects are analyzed. The domain of variation of three predominant parameters is defined allowing to conduct in situ experiments with minimal incidence on the manufacturing disturbance. A mathematical model is proposed to quantify the crushed sand fines by analytical expression that takes into account the interaction between influencing parameters. Practical implications The conducted experiments provided new data that will help to enhance and to better set up the settings of the parameters influencing the rate of filler. The proposed expression constitutes a practical tool for the manufacturer to fix the operating parameters values that results in a desired target fines contents. Originality/value Modeling and optimization of the sand crushing plant, considered here as a case study, has not been attempted previously. The conducted experiments and the proposed mathematical model constitute an original work of this study.

The influence of localized mechanical stresses on the non-homogeneous distribution of electrical conductivity

2016 ◽  
Vol 35 (6) ◽  
pp. 1983-1995 ◽  
Author(s):  
Ewa Napieralska-Juszczak ◽  
Piotr Napieralski ◽  
Krzysztof Komeza ◽  
Youcef Zeroukhi
Keyword(s):  
Electrical Conductivity ◽  
Design Methodology ◽  
Simulation Method ◽  
Uneven Distribution ◽  
Design Parameters ◽  
Homogeneous Distribution ◽  
Physical Parameters ◽  
Total Resistance ◽  
Content Type ◽  
Practical Implications

Purpose The purpose of this paper is to determine the physical design parameters that influence the total resistance of a twisted conductor (cable). One of the physical parameters characterizing this type of structures is the uneven distribution of resistivity due to hardening, which is the result of stress exerted on the wires during the manufacturing process. Design/methodology/approach The authors have developed a method to take into account the effect of localized hardening on the inhomogeneous distribution of electrical conductivity in the distorted structures of the conductor. To achieve this goal, the authors have implemented a mechanical-electrical simulation method. The resistance characteristics have been measured as a function of mechanical stress. Findings As demonstrated by the results of measurements conducted on various samples and with various cable design parameters, the resistance of a given material (copper or aluminum), expressed as a function of stress, does not depend on the type of force applied. Therefore, the same characteristics may be applied to various cable designs. Practical implications The method presented in this paper enables more detailed investigation of the influence of particular design parameters on the total resistance of a cable. It also provides the ability to determine optimal settings of design parameters. Originality/value The approach is distinct from similar studies because it takes into account the deformed geometry of the conductor and the uneven distribution of the resistivity within a filament. In the literature, it is sometimes stated that the distribution of resistivity in a compacted cable is uneven, but its measurement is deemed impossible. This paper provides a method for determining such a distribution.

Sign in / Sign up

Export Citation Format

Share Document