Supersaturated designs (SSDs) constitute an important class of fractional factorial designs that could be extremely useful in factor screening experiments. Most of the existing studies have focused on balanced designs. This paper provides a new lower bound for the \(E(f_{NOD})\)-optimality measure of SSDs with general run sizes. This bound is a generalization of existing bounds since it is applicable to both balanced and unbalanced designs. Optimal multi and mixed-level, balanced and nearly balanced SSDs are constructed by applying a k-circulant type methodology. Necessary and sufficient conditions are introduced for the generator vectors, in order to pre-ensure the optimality of the constructed k-circulant SSDs. The provided lower bounds were used to measure the efficiency of the generated designs. The presented methodology leads to a number of new families of improved SSDs, providing tools for directly constructing optimal or nearly-optimal k-circulant designs by just checking the corresponding generator vector. 相似文献
Family influences on economic performance are investigated. In particular, sibship sex composition is related to hourly wages using data from the National Longitudinal Survey of Youth 1979. The wages of men are increasing in the proportion of siblings who are brothers, but the wages of women are insensitive to sibling gender. Nonwage outcomes are generally unaffected. Contrasts by age structure and demographic group are also presented. The analysis addresses econometric challenges like the endogeneity of fertility and selection into the workforce. In addition, mechanisms such as labour market interactions, human capital investment and role model effects are documented. A questionnaire on job search indicates a same-gender bias in the use of brothers and sisters in obtaining employment. Developmental and psychological assessments suggest that brothers may be associated with worse childhood home environments and more traditional family attitudes among women. The findings are policy relevant and contribute to an understanding of gender differences and earnings inequality. 相似文献
This research is the first to describe financial knowledge in the Islamic Republic of Iran. Data were collected from a convenience sample of investors in the Tehran Stock Exchange. The data were used to examine objective and subjective knowledge as well as overconfidence in one's financial knowledge. The results indicated that compared with other populations, Iranians did not perform well on either basic or advanced financial knowledge questions, especially when the questions dealt with interest rates. This is likely related to the Islamic law ban on usury‐based investing. Regression analysis indicated that demographic charactristics related to basic financial knowledge were income, labour force status and being a student. Demographic characteristics related to advanced financial knowledge were education, labour force status and age. Higher income and education reduced the odds of being overconfident about one's financial knowledge, while being a student and male increased the odds. The article concludes with recommendations about future research as well as building a national financial education strategy. 相似文献
When tournament effect is negative, under complete information, whether patent protection increases the incentive for R&D is ambiguous. It depends on the extent of spillover of the new technology. In particular if that amount is less than a threshold value then patent protection increases the incentive for R&D, otherwise it does not. This note considers incomplete information framework where the spillover parameter is private information. In this framework it is shown that there are situations where patent protection unambiguously increases incentive for R&D. This happens if the distribution function of the spillover parameter is sufficiently skewed and the cost of doing research is sufficiently high even when tournament effect is negative.
The optimality of designs obtained by adding p runs to an orthogonal array is studied for experiments involving m factors each at s levels. The optimality criterion used here, is the Type 1 criterion due to Cheng (1978) which is an extension of Kiefer (1975)
universal optimality criterion. Unlike what happens with orthogonal array plus one run designs, the behavior of designs obtained
via augmentation of an orthogonal array by p runs depends on the particular runs added. 相似文献
This paper deals with Bayesian design over U-type designs of n runs and s factors with q levels for nonparametric response surface prediction. The criterion is developed in terms of the asymptotic approach of Mitchell
et al. (Ann Statist 22: 634–651, 1994) for a specific covariance kernel. An optimal design is given in approximate design
theory over the all level combinations. A connection with orthogonality and aberration is established. A lower bound for the
criterion is provided, and numerical results show that this lower bound is tight. 相似文献
What are the positive and normative implications of eliminating bankruptcy protection for indebted individuals? Without bankruptcy protection, creditors can collect on defaulted debt to the extent permitted by wage garnishment laws. The elimination lowers the default premium on unsecured debt and permits low-net-worth individuals suffering bad earnings shocks to smooth consumption by borrowing. There is a large increase in consumer debt financed essentially by super-wealthy individuals, a modest drop in capital per worker, and a higher frequency of consumer default. Average welfare rises by 1% of consumption in perpetuity, with about 90% of households favoring the change. 相似文献
With implications for navigation, safety, entertainment and vehicle maintenance as well as regulation and infrastructure investment in roads, telematics has the potential to transform driving more than any other innovation for decades. In the already well-established Asian telematics industry, revenue tends to come from extra charges at the time of vehicle-sale, with most subsequent services provided free. The US model has evolved differently, with much of the cost of telematics hardware and software subsidized in the initial vehicle sale price and revenue coming from services used. The decision to invest in telematics is therefore riskier in the US. This article first briefly summarizes the potential of telematics. It then analyzes the investment risks, particularly for automakers. It concludes with recommendations on how the US auto industry can minimize risk and make the most of the opportunities. 相似文献