An Evolutionary Algorithm for Sequencing Production on a Paced Assembly Line

A new sequencing method for mixed‐model assembly lines is developed and tested. This method, called the Evolutionary Production Sequencer (EPS) is designed to maximize production on an assembly line. The performance of EPS is evaluated using three measures: minimum cycle time necessary to achieve 100% completion without rework, percent of items completed without rework for a given cycle time, and sequence “smoothness.” The first two of these measures are based on a simulated production system. Characteristics of the system, such as assembly line station length, assembly time and cycle time, are varied to better gauge the performance of EPS. More fundamental variation is studied by modeling two production systems. In one set of tests, the system consists of an assembly line in isolation (i.e., a single‐level system). In another set of tests, the production system consists of the assembly line and the fabrication system supplying components to the line (i.e., a two‐level system). Sequence smoothness is measured by the mean absolute deviation (MAD) between actual component usage and the ideal usage at each point in the production sequence. The performance of EPS is compared to those of well‐known assembly line sequencing techniques developed by Miltenburg (1989), Okamura and Yamashina (1979), and Yano and Rachamadugu (1991). EPS performed very well under all test conditions when the criterion of success was either minimum cycle time necessary to achieve 100% production without rework or percent of items completed without rework for a given cycle time. When MAD was the criterion of success, EPS was found inferior to the Miltenburg heuristic but better than the other two production‐oriented techniques.     

Gross primary productivity of a large metropolitan region in midsummer using high spatial resolution satellite imagery

Although gross primary productivity (GPP) is estimated with remote sensing over large regions of Earth, urban areas are usually excluded due to the lack of light use efficiency (LUE) parameters for urban vegetation and the spatial heterogeneity of urban land cover. Here, we estimated midsummer GPP, both within and among vegetation and land-use types, across the Minneapolis-Saint Paul, Minnesota metropolitan region. We derived LUE parameters for urban vegetation types using estimates of GPP from tree sap flow and eddy covariance CO₂ flux observations, and from fraction of absorbed photosynthetically active radiation based on 2 m resolution WorldView-2 satellite imagery. Mean GPP per unit land area (including vegetation, impervious surfaces, and soil) was 2.64 g C m^?2 d^?1, and was 4.45 g C m^?2 d^?1 per unit vegetated area. Mapped GPP estimates were within 11.4% of estimates from independent tall tower eddy covariance measurements. Turf grass GPP had a larger coefficient of variation (0.18) than other vegetation classes (~0.10). Vegetation composition was largely consistent across the study area. Excluding golf courses, mean land-use GPP for the total study area varied more by percent vegetation cover (R²?=?0.98, p?<?0.001) than by variability within vegetation classes (R²?=?0.21, p?=?0.19). Urban GPP in general was less than half that of natural forests and grasslands in the same climate zone.     

Keeping the family balance – adult daughters’ experiences of roles and strategies when supporting caring fathers

The Scandinavian countries represent a progressive approach to gender equality and transitions of traditional gender roles but little attention has been paid to gender equality in old age and how normative constructions of gender intersect in the lives of family carers. The aim of this study was to understand how adult daughters experience their roles and strategies when supporting fathers caring for an ill mother. A sample of eight daughters shared their experiences through in-depth interviews. The findings show that the daughters provide substantial and crucial effort and are intimately involved in the caring for their father and the sole contributors towards the emotional support of their fathers. They tend to devote a lot of energy towards picturing their family as ‘normal’ in terms of the family members adopting traditional roles and activities inside as well as outside the family context. In conclusion, the lack of understanding about gender as a ‘norm producer’ is something that needs to be further elaborated upon in order for professionals to encounter norm-breaking behaviours. The daughters’ position as family carers is often assumed and taken for granted since the intersecting structures that impact on the situations of the daughters are largely invisible.     

Posterior sampling in two classes of multivariate fractionally integrated models: corrigendum to Ravishanker,N. and B. K. Ray (1997) Australian Journal of Statistics 39 (3), 295–311

We discuss posterior sampling for two distinct multivariate generalisations of the univariate autoregressive integrated moving average (ARIMA) model with fractional integration. The existing approach to Bayesian estimation, introduced by Ravishanker & Ray, claims to provide a posterior‐sampling algorithm for fractionally integrated vector autoregressive moving averages (FIVARMAs). We show that this algorithm produces posterior draws for vector autoregressive fractionally integrated moving averages (VARFIMAs), a model of independent interest that has not previously received attention in the Bayesian literature.     

THE ROLE OF NATIONAL DEBTS IN THE DETERMINATION OF THE YEN‐DOLLAR EXCHANGE RATE

An intertemporal optimization model is developed to examine the determinants of the long‐run nominal yen‐dollar exchange rate in the presence of national debts. The model is tested empirically using data from Japan and the United States. The proposed theoretical specification is well supported by the data and shows that relative national debts as well as monetary and financial factors may play a significant role in the determination of the long‐run nominal exchange rate between the yen and the dollar. (JEL F31, G11, G15)     

Familism, Interparental Conflict, and Parenting in Mexican-Origin Families: A Cultural-Contextual Framework

The present investigation examined the relations between the cultural belief of familism and various aspects of family functioning and child adjustment, including interparental conflict, parenting, and children's attachment to school, in a sample of 549 two-parent Mexican-origin families. The results indicated that parents' familistic values were negatively associated with interparental conflict for both mothers and fathers. Parents' familistic values were also indirectly associated with parenting through the marital relationship. Interparental conflict was negatively associated with nurturant-involved parenting for both parents, but particularly for fathers. Interparental conflict had an indirect negative effect on children's attachment to school via mothers' and fathers' nurturant-involved parenting. Both paternal and maternal nurturant-involved parenting behaviors were positively associated with children's attachment to school across two time points. Child gender differences are also discussed.     

Adverse Childhood Experiences and Disordered Gambling: Assessing the Mediating Role of Emotion Dysregulation

Adverse childhood experiences (ACEs), such as sexual and physical abuse, have been established as risk factors for the development of disordered gambling. The underlying mechanism by which ACEs influence disordered gambling, however, remains unknown. The aims of the present research were to comprehensively investigate ten types of childhood adversity and their relationships to disordered gambling in adulthood, and to test whether emotion dysregulation mediated the relationship between ACEs and disordered gambling. A sample of community gamblers (N = 414) completed self-report measures of ACEs, emotion dysregulation, and gambling severity. Results revealed a significant association between all but one type (physical abuse) of ACEs and disordered gambling. Further, the results highlighted the cumulative impact of ACEs on gambling. Specifically, individuals who experienced three or more types of ACEs were more than three times as likely to report disordered gambling as compared to individuals with no history of childhood adversity. Importantly, as hypothesized, emotion dysregulation mediated the relationship between ACEs and disordered gambling. Findings from this research describe the association between ACEs and gambling and indicate a causal link between childhood adversity and disordered gambling. Results suggest that treatment initiatives may do well to address both ACEs and emotion dysregulation in the treatment of problem gambling.     

Dogmatism and Systems Development Personnel Performance

This research explores the relationship between the personal variable, dogmatism, and the performance evaluations of systems analysts within a Fortune 500 company. The Rokeach Dogmatism Scale was used to measure the analysts’ level of dogmatism. The analysts’ performance measurement was the product of the company's annual evaluation process. The results of the research indicate that personnel with the highest dogmatism scores generally receive the extreme performance ratings. The results of this study provide further support to consider dogmatism as an important personal variable influencing systems analyst job performance.