scholarly journals A Modified Expectation Maximization Approach for Process Data Rectification

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 270
Author(s):  
Weiwei Jiang ◽  
Rongqiang Li ◽  
Deshun Cao ◽  
Chuankun Li ◽  
Shaohui Tao
Keyword(s):  
Standard Deviation ◽  
Random Error ◽  
Expectation Maximization ◽  
Online Optimization ◽  
Process Data ◽  
Data Rectification ◽  
Advanced Control ◽  
And Performance ◽  
Process Measurements

Process measurements are contaminated by random and/or gross measuring errors, which degenerates performances of data-based strategies for enhancing process performances, such as online optimization and advanced control. Many approaches have been proposed to reduce the influence of measuring errors, among which expectation maximization (EM) is a novel and parameter-free one proposed recently. In this study, we studied the EM approach in detail and argued that the original EM approach is not feasible to rectify measurements contaminated by persistent biases, which is a pitfall of the original EM approach. So, we propose a modified EM approach here to circumvent this pitfall by fixing the standard deviation of random error mode. The modified EM approach was evaluated by several benchmark cases of process data rectification from literatures. The results show advantages of the proposed approach to the original EM in solving efficiency and performance of data rectification.

scholarly journals X̅ and R control charts based on marshall-olkin inverse log-logistic distribution for positive skewed data

2020 ◽  
Vol 1 (1) ◽  
pp. 9-16
Author(s):  
O. L. Aako ◽  
J. A. Adewara ◽  
K. S Adekeye ◽  
E. B. Nkemnole
Keyword(s):  
Control Chart ◽  
Control Charts ◽  
Average Run Length ◽  
Logistic Distribution ◽  
Skewed Data ◽  
Process Data ◽  
And Performance ◽  
Set Up ◽  
Control Limits ◽  
Normally Distributed

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.

System Characterization and Plasma-Particle Distribution Analysis for Development of a Closed Loop Control for Plasma Spray

2000 ◽  
Author(s):  
M. Gevelber ◽  
D. Wroblewski ◽  
J. Fincke ◽  
W. D. Swank
Keyword(s):  
Plasma Spray ◽  
Spray Deposition ◽  
Distribution Analysis ◽  
Real Time Control ◽  
Critical System ◽  
Loop Control ◽  
Time Control ◽  
System Characterization ◽  
Advanced Control ◽  
And Performance

Abstract This paper investigates the need to develop an advanced control system for plasma spray deposition. The limitations and performance capability of both feed forward and real-time control are evaluated. Critical system characteristics for developing such controllers are experimentally identified including dominant nonlinearalities; dynamics, cross-coupling, distributions, and sensor issues.

EXPRESS: Gender (Still) Matters in Business School

2020 ◽  
pp. 002224372097236
Author(s):  
Aradhna Krishna ◽  
A. Yeşim Orhun
Keyword(s):  
Standard Deviation ◽  
Gender Stereotypes ◽  
Business School ◽  
Role Models ◽  
Gender Performance ◽  
Performance Expectations ◽  
Increase Student Achievement ◽  
Administrative Dataset ◽  
Academic Aptitude ◽  
And Performance

This research documents systematic gender performance differences (GPD) at a top business school using a unique administrative dataset and survey of students. The findings show that women’s grades are 11% of a standard deviation lower in quantitative courses than those of men with similar academic aptitude and demographics, and men’s grades are 23% of a standard deviation lower in nonquantitative courses than those of comparable women. The authors discuss and test for different reasons for this finding. They show that a female instructor significantly cuts down GPD for quantitative courses by raising the grades of women. In addition, female instructors increase women’s interest and performance expectations in these courses and are perceived as role models by their female students. These results provide support for a gender stereotype process for GPD and show that faculty can serve as powerful exemplars to challenge gender stereotypes and increase student achievement. The authors discuss several important implications of these findings for business schools and for society.

Collaborative Study of Modified Elmore Method for Mercury in Formulations

1971 ◽  
Vol 54 (3) ◽  
pp. 685-687
Author(s):  
James E Launer
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Random Error ◽  
Collaborative Study ◽  
Test Pair ◽  
Titrimetric Method ◽  
Mercuric Nitrate ◽  
Thiocyanate Solution ◽  
Diluted Solution ◽  
Bearing Materials

Abstract The titrimetric method for mercury described by Elmore in 1946 was modified and collaboratively studied with formulations containing 6.7% phenylmercury urea in one test pair and 1% mercuric nitrate in another test pair. Mercury is determined in diluted solution, following reflux at 30 drops/min with fuming H2SO4-red fuming HNO3, by titration with standard thiocyanate solution, using ferric alum as indicator. The method is not applicable in presence of large quantities of chlorine-bearing materials. Single determinations on 4 samples by 14 collaborators showed that the standard deviation estimation of random error was 0.058 for phenylmercury urea and 0.004 for mercuric nitrate. Standard deviation estimates of systematic error were 0.048 and 0.009, respectively. The method has been adopted as official first action.

Riders’ perception of symmetrical pressure on their ischial tuberosities and rein contact tension whilst sitting on a static object

2017 ◽  
Vol 13 (1) ◽  
pp. 7-12 ◽  
Author(s):  
R. Guire ◽  
H. Mathie ◽  
M. Fisher ◽  
D. Fisher
Keyword(s):  
Standard Deviation ◽  
Solid Wall ◽  
Static Model ◽  
Ischial Tuberosity ◽  
Static Object ◽  
Left And Right ◽  
And Performance ◽  
The Right ◽  
Ischial Tuberosities ◽  
Paired T Test

The horse-rider system is of great interest in understanding the mechanics involved in optimising locomotor function and performance in the ridden horse. Adult riders (n=30) attending a rider conference volunteered to take part in the study. Riders were asked to mimic riding position by positioning themselves symmetrically on their seat bones (ischial tuberosities) sitting on a (Pliance) pressure mat which was placed on a static platform. Riders were also asked to mimic even rein contact using reins with gauges which were attached to a solid wall. When satisfied that they were sitting symmetrically and had an even rein contact, pressure and rein measurements were captured for 5 s and repeated three times. A paired T Test was carried out to determine differences between left and right ischial tuberosities and rein pressures. Using a static model, this study found that the riders had significantly more pressure beneath the left ischial tuberosity (mean ± standard deviation, 3.22±1.43 N/cm2) compared to the right (2.65±1.49 N/cm2) (P=0.04) and no significant differences were observed between left (6.37±2.42 N) and right rein pressure (6.38±2.66 N) (P=0.95). Whilst sitting on a static platform, differences in ischial tuberosity pressure in adult riders were observed despite these riders’ perception that their seat was symmetrically weighted. These differences observed need to be investigated further, dynamically, to determine if there is a similar trend in the ridden situation.

scholarly journals A dynamic model and performance analysis of a stepped rotary flow control valve

2019 ◽  
Vol 233 (9) ◽  
pp. 1195-1208 ◽  
Author(s):  
Karem Abuowda ◽  
Siamak Noroozi ◽  
Mihai Dupac ◽  
Phil Godfry
Keyword(s):  
Linear Time ◽  
Control Valve ◽  
Flow Control Valve ◽  
Main Concept ◽  
Linear Time Invariant ◽  
Dynamic Representation ◽  
Advanced Control ◽  
And Performance ◽  
Time Invariant ◽  
Rotary Type

The hydraulic independent metering is an advanced actuator driving technique that allows the implementation of advanced control algorithms or methods. The main concept of independent metering is to control hydraulic actuators ports, which are the meter-in and meter-out, separately. In this article, a novel stepped rotary type valve has been developed for embedding in hydraulic independent metering systems, instead of conventional types such as poppet and spool. The insertion leads to developing different and novel control techniques, which require software-in-the-loop simulation and hardware-in-the-loop simulation of the proposed system. The paper explores the dynamic representation of this valve and defines its own performance limitations. This includes the development of a linear model comprising its two main subparts which are the stepper motor and the rotary orifice. Consequently, the linear time-invariant methods are used to explore the performance of the valve by considering the effect of different parameters namely the pressure drop, friction coefficient, damping coefficient, and bristle coefficient.

scholarly journals Comportamiento táctico de jugadores de fútbol de diferentes posiciones, durante una temporada deportiva (Tactical behaviour of soccer players from different playing positions throughout a season)

Retos ◽  
2020 ◽  
pp. 1-6
Author(s):  
Pedro Emilio Drumond Moreira ◽  
Raphael Brito e Sousa ◽  
Juan Carlos Pérez Morales ◽  
Pablo Juan Greco ◽  
María Perla Moreno Arroyo ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Field Test ◽  
Soccer Players ◽  
And Performance

El estudio comparó el comportamiento y el desempeño táctico de jóvenes jugadores de fútbol de diferentes posiciones, durante una temporada deportiva. Participaron en el estudio defensores (n=seis), centrocampistas (n=15) y atacantes (n=nueve), (media=14.1 años; desviación estándar=0.6). Se aplicó la prueba de campo de FUT-SAT, que posibilita la evaluación de la incidencia de los principios tácticos ofensivos y defensivos, así como el porcentaje de acierto ofensivo y defensivo. Para realizar el análisis de los datos se utilizó un ANOVA de dos vías para la comparación de los principios tácticos en las posiciones (defensores, centrocampistas y atacantes) durante la temporada. Los resultados mostraron que los atacantes realizaron más acciones en el principio ofensivo de espacio que los defensores y centrocampistas, durante toda la temporada (p = .04). Además, se verificó una mejora del rendimiento táctico (p =.001) y cambios en los principios de unidad ofensiva y cobertura defensiva, en todas las posiciones (p =.001).  Abstract. This study aimed at comparing tactical behavior and performance of soccer players from different playing positions throughout a season. The sample was composed of defenders (n=six), midfielders (n=15) and forwards (n=nine) (mean age 14.1, standard deviation=0.6). The players were evaluated using the FUT-SAT field test, which allows the evaluation of offensive and defensive incidence of tactical principles, as well as the percentage of positive tactical actions. Data were compared by a two-way ANOVA considering the factor “playing position” (defender, midfielder, and forward) throughout the season. Forwards carried out more actions on the offensive principle of space and width than defenders and midfielders throughout the season (p = .04). In addition, an improvement in tactical performance was verified (p = .001), as well as some variations regarding the incidence of offensive unity and defensive coverage actions throughout the season in all positions (p = .001).

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