Manufacturing cycle time reduction using balance control in the semiconductor fabrication line

In semiconductor manufacturing, wafer fabrication is the most complicated and important process, and is composed of several hundred process steps and involves several hundred machines. The productivity of the manufacturing process depends mainly on controlling the balance of WIP (work-inprogress) flow to achieve maximum throughput under short manufacturing cycle times. This paper discusses how to determine the proper WIP level for operations, against which balance status can be measured. Balance measurement can be applied in mathematical modelling for bottleneck scheduling and operations management of the fabrication line. Performances are evaluated through computational experiments to show that balance driven management leads to 15-33% more production in 21% shorter manufacturing cycle time than production driven management.     

Risk and protective factors for child neglect during early childhood: A cross-study comparison

The present analysis relies upon data from three separate longitudinal studies to identify risk and protective factors associated with subsequent neglect during early childhood. All three studies (Fragile Families and Child Wellbeing [FFCW]; Healthy Families New York [HFNY]; Illinois Families Study-Child Wellbeing [IFS]) involve probabilistic samples or subsamples of low-income families with young children. Multivariate logistic regressions predicting official reports of investigated neglect allegations and a dichotomous indicator of neglect from the Parent-child Conflict Tactics Scale (CTS-PC) were conducted separately for each study, using common sets of predictors derived from baseline or initial survey waves. Across the three studies, consistencies emerged with respect to the predictors of both neglect outcomes. Specifically, consistencies emerged related to indicators of economic resources and hardships, parent well-being, and parenting. Understanding the predictors of child neglect is of critical importance to the development of child maltreatment prevention strategies since a clearer understanding of the risk and protective factors associated with neglect would enable more effectively targeted and tailored interventions.     

Physical and Psycho-Social Predictors of Adolescents’ Suicide Behaviors

The current study examined the relationship between suicidal behaviors and physical and psycho-social predictors including body image, weight control behaviors, and risky sexual behaviors among Asian, African American, Caucasian, and Hispanic adolescents. This study used the 2007 Youth Risk Behavior Survey (YRBS). The target populations were 11,134 adolescents (5,636 female and 5,498 male) in 9th–12th grade who completed the survey. A linear regression was conducted to examine the correlation between predictors and suicidal behaviors. The results showed that gender, grade, depression, substance use, body image, weight control behaviors, and risky sexual behaviors were significant predictors of adolescents’ suicidal behaviors, while race/ethnicity was not a good predictor. Also, there were significant gender and grade differences in suicidal behaviors. Based on the results, practice implications for suicide prevention were discussed.     

Does teacher educational training help the early math skills of English language learners in Head Start?

To address the early performance gap between native-born and immigrant children and to seek ways to reduce the disparity, the study explored the effect of teacher qualification on early math skills of preschoolers, with focused attention to immigrant children. Particularly, the study examined the effects of teacher educational levels, certification, and professional training, by employing Hierarchical Linear Modeling (HLM) analysis to a US nationally representative database from the Head Start Family and Child Experiences (FACES). The study found a significantly positive effect of teacher qualification for immigrant preschoolers in Head Start, who displayed lower early math skills than their native-born counterparts. Among immigrant preschoolers, those who were with teachers of lower educational levels showed significantly lower early math skills compared with their immigrant peers with teachers of higher educational levels. The study also supported teacher certification and professional training as potential mediators in promoting early math competency of immigrant students, especially with teachers of lower educational levels.     

Industrialization,Productivity and the Shift to Services and Information

All major world economies are exhibiting a shift from products to services in terms of relative share of GNP and employment. A well accepted explanation for this shift to services has been the lower productivity growth in services relative to manufacturing. A second trend visible in the United States and other advanced economies is that from material‐intensive to information‐intensive sectors with the latter growing relative to the former. There does not seem to be a generally accepted explanation for this shift; in fact, here it would appear that productivity in information‐intensive sectors is increasing. We construct a model of an economy with endogenous production and consumption decisions by utility maximizing individuals. We show that differential productivity changes can result in either relative growth or decline of a sector. A second factor affecting the direction of change is the degree to which consumption of sector outputs approaches satiation. When marginal utility of additional consumption drops sufficiently low, productivity increases can lead to declines in the relative size and share of, and employment in the sector. Concurrently, increases in productivity increase average wealth as expected, but income inequality can either increase or decrease.