scholarly journals A Nonparametric Scheme for Monitoring a Process Output with a Block Effect

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Saad T. Bakir

This paper proposes a distribution-free (or nonparametric) control scheme to monitor a process output that contains two special causes of variation called “block or batch” effects and “treatment or position” effects. The scheme properties (control limits, false alarm rate, and in-control average run length) stay the same under any assumed continuous probability distribution. For moderate sample sizes, these properties can be computed exactly from available tables without the need to estimate the mean or variance of the process. The proposed monitoring scheme requires ranking the observations within blocks and using the method of analysis of means by ranks. The paper includes an illustrative example concerning the grinding process of silicon wafers used in integrated circuits production.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Johnson A. Adewara ◽  
Kayode S. Adekeye ◽  
Olubisi L. Aako

In this paper, two methods of control chart were proposed to monitor the process based on the two-parameter Gompertz distribution. The proposed methods are the Gompertz Shewhart approach and Gompertz skewness correction method. A simulation study was conducted to compare the performance of the proposed chart with that of the skewness correction approach for various sample sizes. Furthermore, real-life data on thickness of paint on refrigerators which are nonnormal data that have attributes of a Gompertz distribution were used to illustrate the proposed control chart. The coverage probability (CP), control limit interval (CLI), and average run length (ARL) were used to measure the performance of the two methods. It was found that the Gompertz exact method where the control limits are calculated through the percentiles of the underline distribution has the highest coverage probability, while the Gompertz Shewhart approach and Gompertz skewness correction method have the least CLI and ARL. Hence, the two-parameter Gompertz-based methods would detect out-of-control faster for Gompertz-based X¯ charts.


2020 ◽  
Vol 1 (1) ◽  
pp. 9-16
Author(s):  
O. L. Aako ◽  
J. A. Adewara ◽  
K. S Adekeye ◽  
E. B. Nkemnole

The fundamental assumption of variable control charts is that the data are normally distributed and spread randomly about the mean. Process data are not always normally distributed, hence there is need to set up appropriate control charts that gives accurate control limits to monitor processes that are skewed. In this study Shewhart-type control charts for monitoring positively skewed data that are assumed to be from Marshall-Olkin Inverse Loglogistic Distribution (MOILLD) was developed. Average Run Length (ARL) and Control Limits Interval (CLI) were adopted to assess the stability and performance of the MOILLD control chart. The results obtained were compared with Classical Shewhart (CS) and Skewness Correction (SC) control charts using the ARL and CLI. It was discovered that the control charts based on MOILLD performed better and are more stable compare to CS and SC control charts. It is therefore recommended that for positively skewed data, a Marshall-Olkin Inverse Loglogistic Distribution based control chart will be more appropriate.


2018 ◽  
Vol 17 (1) ◽  
Author(s):  
Darmanto Darmanto

<p><em>The manufacturing production process that is currently trend is short-run. Short-run process is a job shop and a just in-time. These causes the process parameters to be unknown due to unavailability of data and generally a small amount of product. The control chart is one of the control charts which  designed for the short run. The procedure of the control chart follows the concept of succesive difference and under the assumption of the multivariate Normal distribution. The sensitivity level of a control chart is evaluated based on the average run length (ARL) value. In this study, the ARL value was calculated based on the shift simulation of the average vector by recording the first m-point out of the control limits. The average vector shift simulation of the target () is performed simultaneously with the properties of a positive shift (=+ δ). Variations of data size and many variables in this study were m = 20, 50 and p = 2, 4, 8, respectively. Each scheme (a combination of δ, m and p) is iterated 250,000 times. The simulation results show that for all schemes when both parameters are known ARL<sub>0 </sub>≈ 370. But, when parameters are unknown, ARL<sub>1</sub> turn to smaller. This conclusion also implied when the number of p and n are increased, it reduce the sensitivity of the control chart.</em></p>


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ahmed Ibrahim Shawky ◽  
Muhammad Aslam ◽  
Khushnoor Khan

In this paper, a control chart scheme has been introduced for the mean monitoring using gamma distribution for belief statistics using multiple dependent (deferred) state sampling under the neutrosophic statistics. The coefficients of the control chart and the neutrosophic average run lengths have been estimated for specific false alarm probabilities under various process conditions. The offered chart has been compared with the existing classical chart through simulation and the real data. From the comparison, it is concluded that the performance of the proposed chart is better than that of the existing chart in terms of average run length under uncertain environment. The proposed chart has the ability to detect a shift quickly than the existing chart. It has been observed that the proposed chart is efficient in quick monitoring of the out-of-control process and a cherished addition in the toolkit of the quality control personnel.


2021 ◽  
Vol 932 ◽  
Author(s):  
Yitong Fan ◽  
Marco Atzori ◽  
Ricardo Vinuesa ◽  
Davide Gatti ◽  
Philipp Schlatter ◽  
...  

The application of drag-control strategies on canonical wall-bounded turbulence, such as periodic channel and zero- or adverse-pressure-gradient boundary layers, raises the question on how to distinguish consistently the origin of control effects under different reference conditions. We employ the RD identity (Renard & Deck, J. Fluid Mech., vol. 790, 2016, pp. 339–367) to decompose the mean friction drag and investigate the control effects of uniform blowing and suction applied to an NACA4412 airfoil at chord Reynolds numbers $Re_c=200\,000$ and $400\,000$ . The connection of the drag reduction/increase by using blowing/suction with the turbulence statistics (including viscous dissipation, turbulence kinetic energy production and spatial growth of the flow) across the boundary layer, subjected to adverse or favourable pressure gradients, is examined. We found that the inner and outer peaks of the contributions associated with the friction-drag generation show good scaling with either inner or outer units, respectively. They are also independent of the Reynolds number, control scheme and intensity of the blowing/suction. The small- and large-scale structures are separated with an adaptive scale-decomposition method, namely the empirical mode decomposition (EMD), which aims to analyse the scale-specific contribution of turbulent motions to friction-drag generation. Results unveil that blowing on the suction side of the airfoil is able to enhance the contribution of large-scale motions and to suppress that of small scales; however, suction behaves contrarily. The contributions related to cross-scale interactions remain almost unchanged with different control strategies.


Author(s):  
N. David Theodore ◽  
Mike Dreyer ◽  
Charles Varker

Al-1.5%Cu materials are of interest for interconnect-metallization in semiconductor integrated-circuits. It is known from the literature that the mean-time-to-failure (MTF) due to electromigration of the Al-1.5%Cu interconnects depends on the microstructure of the materials. A correlation is seen for instance between grain-size distributions in the material and the MTF. Uniform large-grained distributions improve lifetime. The present study evaluated the microstructure of Al-1.5%Cu films deposited and annealed under different conditions.Al-1.5%Cu films had been deposited at 25°C and at 300°C; the layers had then been annealed at 300°C for 17 hours, prior to TEM investigation. Plan-view TEM specimens were prepared in the 100 substrategeometry, and cross-section TEM specimens were prepared in the 110 substrate-geometry. These were then analyzed using bright-field and dark-field TEM imaging techniques. A JEOL JEM 200CX transmission electron microscope was used for the investigation, operating at 200 kV.


2020 ◽  
Vol 17 (7) ◽  
pp. 2926-2931
Author(s):  
Masoud Mohammadi ◽  
Mahmood Seifouri ◽  
Elham Boyerahmadi ◽  
R. Udaiyakumar

In this paper, an ultra-compact photonic crystal sensor based resonant cavities is proposed with improved quality factor, sensitivity and detection limit. The proposed sensor has 2D pillar photonic crystals with hexagonal array of dielectric rods. The refractive index of dielectric rods, radius of rods, filling factor (r/a) and lattice constant of the proposed structure are 3.46, 108 nm, 0.2 and 542 nm, respectively. The mean transmission efficiency, Quality factor, sensitivity, Figure of Merit (FOM) and limit of detection (LOD) are calculated as 92.2%, 9975.8, 371 nm/RIU, 2366 and 4.5 x 10-5 RIU, respectively. The corresponding electric field distributions and it band characteristics are studied using finite different time domain method (FDTD) and plan wave expansion (PWE). The cross-section of the proposed structure is 86 /xm2 and is desirable for photonic integrated circuits (PIC) and ultra-compact optical sensors.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eva Díaz ◽  
Guillermo Herrera ◽  
Simón Oyarzún ◽  
Raul C. Munoz

AbstractWe report the resistivity of 5 Cu films approximately 65 nm thick, measured between 5 and 290 K, and the transverse magnetoresistance and Hall effect measured at temperatures 5 K < T < 50 K. The mean grain diameters are D = (8.9, 9.8, 20.2, 31.5, 34.7) nm, respectively. The magnetoresistance signal is positive in samples where D > L/2 (where L = 39 nm is the electron mean free path in the bulk at room temperature), and negative in samples where D < L/2. The sample where D = 20.2 nm exhibits a negative magnetoresistance at B < 2 Tesla and a positive magnetoresistance at B > 3 Tesla. A negative magnetoresistance in Cu films has been considered evidence of charge transport involving weak Anderson localization. These experiments reveal that electron scattering by disordered grain boundaries found along L leads to weak Anderson localization, confirming the localization phenomenon predicted by the quantum theory of resistivity of nanometric metallic connectors. Anderson localization becomes a severe obstacle for the successful development of the circuit miniaturization effort pursued by the electronic industry, for it leads to a steep rise in the resistivity of nanometric metallic connectors with decreasing wire dimensions (D < L/2) employed in the design of Integrated Circuits.


2017 ◽  
Vol 40 (12) ◽  
pp. 3407-3414 ◽  
Author(s):  
P Jeyadurga ◽  
S Balamurali

In this paper, we propose a new attribute np control chart for monitoring Weibull distributed mean life of a product using a quick switching sampling system. The proposed control chart consists of two pairs of control limits, namely normal and tightened control limits. The optimal parameters of the proposed control chart, such as coefficients of control limits and experiment termination ratio, are determined so that the average run length (ARL) is close to the target in-control ARL. The ARL is calculated for various shift constants for the corresponding determined parameters. The performance of the proposed control chart is evaluated and compared with other existing charts in terms of ARL.


2018 ◽  
Vol 6 (7) ◽  
pp. 382-398
Author(s):  
Doncillo Ma. Liberty B. ◽  
Naelga Sofia C.

In response to the global community problem on solid waste management and the empowerment of the persons with disability (PWDs), this study is focused on Plastiknology development and utilization among persons with disability (PWDs) in Sinacaban, Misamis Occidental, Philippines. The study employed IPO (input process output) model using the respondents’ profile as the input variables and sanitation, sorting, cutting, folding and connecting skills as the process variables. Plastiknology products such as coin purse, clutch bag, wallet and placemats serves as the output variables. Using descriptive statistics, the mean, standard deviation, frequency, percentage and percentage distribution are used to describe each variable. Regression analysis was used to test the input and process variables’ influence on the creation of the output products. Statistics shows minimal background on handicrafts, but interest in trainings is high. Active participation on livelihood trainings was shown in respondents’ positive attendance, attitude and product construction. As a result, there was no significant difference between self-evaluated and post-evaluated skills. Qualitatively, the products of the partcipants are promising and well-constructed. It was therefore recommended that the national and local institutions shall provide livelihood assistance to special sectors such as PWDs by facilitating the continuity of this livelihood program.


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