Joglekar and Tharthare [6] presented an alternate approach for minimizing total inventory carrying and ordering costs of a vendor and the purchaser(s). This approach permits the vendor and the purchaser(s) to rationally select their operating policies. Joglekar and Tharthare claimed that their approach is more economical than the joint lot-size approach. In this note we identify some conceptual issues in their approach and demonstrate the superiority of the joint lot-size approach with the help of an example. 相似文献
This study investigates the impact of worker learning, worker flexibility, and labor attrition on the system performance of a dual resource constrained (DRC) job-shop. The effects of learning and labor attrition have not been previously addressed in DRC literature. Results from the study, consistent with previous literature, show that the greatest benefits are achieved when inter-departmental worker flexibility is incrementally introduced into the system. In addition, the learning environment, which depends on the initial processing time of jobs and the learning rates of workers, is shown to impact the acquisition of flexibility. The study also shows that the impact of labor attrition on system performance under certain shop conditions may be significant. 相似文献
To design (or redesign) a competitive product, it is imperative that both the sales and manufacturing cost implications are assessed in a structured way. That is, the interactive (multidimensional) aspects of manufacturing and marketing variables need to be positioned in a proper perspective so that the system impact of variation in one or more variables may be ascertained quickly. In this paper we show how some of the system-related paradigms can be used as foundations for developing quantitative and qualitative models for tracking such interactive ímpacts. The emphasis is not on building complex mathematical models to solve specific problems but on providing a framework where system properties expressed as simple postulates can be used in an intelligent way to assess the impact of improvements in specific product-process scenarios. 相似文献
AbstractChina is home to approximately 245 million rural-to-urban migrant workers. The influx of migrants into urban areas has posed various challenges for local social service systems. Recently, increasing number of community services have been developed to meet the growing service demands from the migrant population. However, whether increase in community service use results in improved wellbeing among migrant workers remains critically unexplored. As such, this study examines the role of community service use in migrant workers’ life satisfaction and the potential mediating effect of identity integration in Shenzhen, China. Bootstrapped models were adopted to examine relationship among variables. Drawing from a sample of 1,087 rural-to-urban migrant workers, we found that community service use is positively correlated with both identity integration and migrant workers’ life satisfaction. Moreover, identity integration served as a partial mediator between community service use and life satisfaction. The mediating effect of identity integration was found to increase with age. This study highlights that diverse services should be implemented to address divergent needs of migrants in different age groups. Community service can also serve as a vehicle to foster integration among migrant workers in host communities, especially for older age groups. Future studies may further investigate the relationships between community social capital, community social support, quality of community-based organization and frequency of service use so as to optimize the life satisfaction of migrant workers. 相似文献
We examined whether pre‐existing parent psychological distress moderated juvenile offenders’ substance use, sexual risk, and mental health outcomes in a randomized trial. Forty‐seven parent–adolescent dyads received either Family‐based Affect Management Intervention (FAMI) for adolescent substance use and HIV prevention or adolescent‐only Health Promotion Intervention (HPI). Parents’ self‐reported distress at baseline significantly moderated adolescents’ self‐reported marijuana use and alcohol use but not other outcomes at 3 months postintervention, producing crossover interactions. FAMI outperformed HPI when parents reported high‐level distress, whereas HPI outperformed FAMI when parents reported low‐level distress. This finding that the relative efficacy of interventions depends on the severity of parent psychological distress could inform efforts to match substance‐using, justice‐involved adolescents with the intervention most likely to benefit them. 相似文献
We examined how perceived acculturation expectations from parents and school, and ethnic discrimination predicted early adolescents’ heritage and mainstream acculturation orientations at home (private domain) and in school (public domain) one year later. We surveyed 263 early adolescents of immigrant background in Germany (Mage = 10.44 years, 60% female). Multigroup path analyses revealed that perceived acculturation expectations and ethnic discrimination were more strongly related to adolescents’ private than public acculturation orientations. Parental heritage expectations were the strongest predictor of adolescents’ acculturation orientations. Boys were more susceptible than girls to ethnic discrimination and acculturation expectations in school, which affected their private and public acculturation orientations. Results highlight the importance of integrating domain‐specific and gendered experiences when analyzing adolescents’ acculturative development. 相似文献
Individual prosperity and welfare can be measured using both objective and subjective criteria. Although theory and previous research suggest that these two methods can produce corresponding results, the measurements can also be inconsistent. Against this background, the current paper investigates the relationship between the objective income position of older Europeans (aged 50?+?years) and their perception of their financial situation, using the seventh wave of the Survey of Health, Aging, and Retirement in Europe (SHARE) conducted in 2017. The main research questions include (1) how is objective income distributed in old age across Europe?, (2) how do elderly Europeans evaluate their income situation subjectively?, (3) is there a discrepancy between the objective prosperity position and their subjective perception observable?, (4) are there country-specific differences that are observable?, and (5) how can such discrepancies be explained?
The results show that objective income positions can be congruent with subjective self-perceptions, both good (well-being) and bad (deprivation), of one’s income situation. However, this is not always the case, and country-specific variations do exist. In analyzing the causes of the 2 forms of nonconformance—namely, adaptation (satisfaction paradox) and dissonance (dissatisfaction dilemma)—this paper concludes that sociodemographic and socioeconomic determinants alone cannot account for discrepancies. The consideration of certain social-psychological influences or personality traits and especially social comparison processes (namely, with one’s past) is essential in explaining both the satisfaction paradox and the dissatisfaction dilemma.
To perform variable selection in expectile regression, we introduce the elastic-net penalty into expectile regression and propose an elastic-net penalized expectile regression (ER-EN) model. We then adopt the semismooth Newton coordinate descent (SNCD) algorithm to solve the proposed ER-EN model in high-dimensional settings. The advantages of ER-EN model are illustrated via extensive Monte Carlo simulations. The numerical results show that the ER-EN model outperforms the elastic-net penalized least squares regression (LSR-EN), the elastic-net penalized Huber regression (HR-EN), the elastic-net penalized quantile regression (QR-EN) and conventional expectile regression (ER) in terms of variable selection and predictive ability, especially for asymmetric distributions. We also apply the ER-EN model to two real-world applications: relative location of CT slices on the axial axis and metabolism of tacrolimus (Tac) drug. Empirical results also demonstrate the superiority of the ER-EN model. 相似文献
We test the situational impact of two types of resource flexibility, machine flexibility and labor flexibility, in a material requirements planning (MRP)-driven production system. Machine flexibility has not been treated in prior multistage research, only labor flexibility. Machine flexibility is closely related to a plant's positioning strategy. A process-focused plant opts for considerable machine flexibility by choosing general-purpose equipment. Resource flexibility, if effective, can be an attractive alternative to two other types of buffers, inflated inventories and costly capacity cushions. Our simulation results, using factor settings established earlier by a panel of managers, show that resource flexibility is indeed an effective buffer against uncertainties such as end-item demand variability, capacity bottlenecks, equipment failures, and yield losses. Machine flexibility is especially helpful in environments characterized by high uncertainties, tight capacities, and large lot sizes. Worker flexibility has a similar, but less dramatic, impact. Benefits are most striking with customer service, rather than with inventory or labor productivity. Finally, we show that simultaneous introduction of both machine and labor flexibility yields only marginal improvements over either kind of flexibility alone. 相似文献