13 research outputs found
Performance comparison of the exact run-length distribution between the run sum X and EWMA X charts
The run sum (RS) X and exponentially weighted moving average (EWMA) X charts are very
effective in detecting small and moderate process mean shifts. The design of the RS X and
EWMA X charts based on the average run length (ARL) alone, can be misleading and
confusing. This is due to the fact that the run-length distribution of a control chart is highly
right-skewed when the process is in-control or slightly out-of-control; while that for the out-ofcontrol
cases, the run-length distribution is almost symmetric. On the other hand, the percentiles
of the run-length distribution provide the probability of getting a signal by a certain number of
samples. This will benefit practitioners as the percentiles of the run-length distribution give
comprehensive information regarding the behaviour of a control chart. Accordingly, this paper
provides a thorough study of the run-length properties (ARL, standard deviation of the run
length and percentiles of the run-length distribution) for the RS X and EWMA X charts.
Comparative studies show that the EWMA X chart outperforms the RS X charts for detecting
small mean shifts when all the control charts are optimized with respect to a small shift size.
However, the RS X charts surpass the EWMA X chart for all sizes of mean shifts when all
the control charts are optimized with respect to a large shift size
An Expected Average Run Length (EARL) Performance Comparison of the SSGR and EWMA Control Charts
The acceleration use of control charts in industrial processes has led to the effectiveness in their evaluation by quality practitioners. This is crucial, as it influences their decisions on the choice of which control charts to employ. This study aims to explore and compare the performance of the side sensitive group runs (SSGR) and exponentially weighted moving average (EWMA) control charts. In general, the average run length (ARL) characteristics were used to evaluate the performance of these control charts. The ARL, which considers the exact shift size in the process, is restricted in the case when the practitioner cannot identify the process shift size (unknown shift size). In this situation, the expected average run length (EARL) is an alternative performance criterion. Upon comparison of the findings obtained, the EWMA chart has superior performance when (δmin, δmax) = (0.1, 0.4). In contrast, the SSGR chart overtakes the EWMA chart when (δmin, δmax) = (0.5, 0.8) and (δmin, δmax) = (0.9, 1.2), except when the sample size n = 3 for (δmin, δmax) = (0.5, 0.8). For this particular combination, the EWMA chart performs slightly better than the SSGR chart. The outcome of this study is expected to contribute to practitioners in identifying suitable control charts in process monitoring and implementation
An Expected Average Run Length (EARL) Performance Comparison of the SSGR and EWMA Control Charts
The acceleration use of control charts in industrial processes has led to the effectiveness in their evaluation by quality practitioners. This is crucial, as it influences their decisions on the choice of which control charts to employ. This study aims to explore and compare the performance of the side sensitive group runs (SSGR) and exponentially weighted moving average (EWMA) control charts. In general, the average run length (ARL) characteristics were used to evaluate the performance of these control charts. The ARL, which considers the exact shift size in the process, is restricted in the case when the practitioner cannot identify the process shift size (unknown shift size). In this situation, the expected average run length (EARL) is an alternative performance criterion. Upon comparison of the findings obtained, the EWMA chart has superior performance when (δmin, δmax) = (0.1, 0.4). In contrast, the SSGR chart overtakes the EWMA chart when (δmin, δmax) = (0.5, 0.8) and (δmin, δmax) = (0.9, 1.2), except when the sample size n = 3 for (δmin, δmax) = (0.5, 0.8). For this particular combination, the EWMA chart performs slightly better than the SSGR chart. The outcome of this study is expected to contribute to practitioners in identifying suitable control charts in process monitoring and implementation
Magnetic and electrical transport properties of delta-doped amorphous Ge:Mn magnetic semiconductors
10.1016/j.jmmm.2006.01.237Journal of Magnetism and Magnetic Materials3032 SPEC. ISS.e318-e321JMMM
The Effect of Older Sibling, Postnatal Maternal Stress, and Household Factors on Language Development in Two-to Four-Year-Old Children
Previous literature has shown that family structure affects language development. Here, factors relating to older siblings (their presence in the house, sex and age gap), mothers (maternal stress) and household size and residential crowding were examined to systematically examine the different role of these factors. Data from mother-child dyads in a Singaporean birth cohort, (677-855 dyads; 52% males; 58-61% Chinese, 20-24% Malay, 17-19% Indian) collected when children were 24-, 48-, and 54-months old, were analysed. There was a negative effect of having an older sibling, moderated by the siblings’ age gap, but not by the older sibling’s sex, nor household size or residential crowding. Maternal stress affected language outcomes in some analyses but not others. Implications for understanding the effect of family structure on language development are discussed
The Effect of Older Sibling, Postnatal Maternal Stress, and Household Factors on Language Development in Two- to Four-Year-Old Children
Previous literature has shown that family structure affects language development. Here, factors relating to older siblings (their presence in the house, sex and age gap), mothers (maternal stress) and household size and residential crowding were examined to systematically examine the different role of these factors. Data from mother-child dyads in a Singaporean birth cohort, (677-855 dyads; 52% males; 58-61% Chinese, 20-24% Malay, 17-19% Indian) collected when children were 24-, 48-, and 54-months old, were analysed. There was a negative effect of having an older sibling, moderated by the siblings’ age gap, but not by the older sibling’s sex, nor household size or residential crowding. Maternal stress affected language outcomes in some analyses but not others. Implications for understanding the effect of family structure on language development are discussed
Maternal Depressive Symptoms and Risk for Childhood Depression:Role of Executive Functions
Parental and child genetic burden of glycaemic dysregulation and early-life cognitive development: an Asian and European prospective cohort study
Insulin resistance and glucose metabolism have been associated with neurodevelopmental disorders. However, in the metabolically more susceptible Asian populations, it is not clear whether the genetic burden of glycaemic dysregulation influences early-life neurodevelopment. In a multi-ethnic Asian prospective cohort study in Singapore (Growing Up in Singapore Towards healthy Outcomes (GUSTO)), we constructed child and parental polygenic risk scores (PRS) for glycaemic dysregulation based on the largest genome-wide association studies of type 2 diabetes and fasting glucose among Asians. We found that child PRS for HOMA-IR was associated with a lower perceptual reasoning score at ~7 years (β=-0. 141, p-value=0.024, 95%CI -0. 264 to -0. 018) and a lower WIAT-III mean score at ~9 years (β=-0.222, p-value=0.001, 95%CI -0.357 to -0.087). This association were consistent in direction among boys and girls. These inverse associations were not influenced by parental PRS and were likely mediated via insulin resistance rather than mediators such as birth weight and childhood body mass index. Higher paternal PRS for HOMA-IR was suggestively associated with lower child perceptual reasoning at ~7 years (β=-0.172, p-value=0.002, 95%CI -0.280 to -0.064). Replication analysis in a European cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort, showed that higher child PRS for fasting glucose was associated with lower verbal IQ score while higher maternal PRS for insulin resistance was associated with lower performance IQ score in their children at ~8.5 years. In summary, our findings suggest that higher child PRS for HOMA-IR was associated with lower cognitive scores in both Asian and European replication cohorts. Differential findings between cohorts may be attributed to genetic and environmental factors. Further investigation of the functions of the genetic structure and ancestry-specific PRS and a more comprehensive investigation of behavioural mediators may help to understand these findings better