集值决策信息系统属性约简的启发式算法

在集值决策信息系统中,通过引入信息量和条件信息量,对属性的重要性进行了定义.给出了分配约简（广义决策约简）的一种启发式算法：条件信息量约简算法,分析了该算法的时间复杂度,时间复杂度为O（｜A｜3｜U｜2）;最后通过例子说明,该算法能得到集值决策信息系统的一个约简.     

试论汉语的“数量范围”

基于汉语大量的语料事实,文章对汉语“数量范围”的内涵及表现形式进行了分析,认为,汉语“数量范围”除了有常见的表达式外,还具有多种标记词,这些标记词有的可以“对”用,有的可以“叠”用,标记词的“对”用使范围更加具体明确,而“叠”用则对范围起到了确认或强调作用。     

Analysis of postponement strategy by EPQ-based models with planned backorders

This paper develops economic production quantity (EPQ)-based models with planned backorders to evaluate the impact of the postponement strategy on a manufacturer in a supply chain. We derive the optimal total average costs per unit time for producing and keeping n end-products in a postponement system and a non-postponement system, respectively. By comparing the optimal total average costs of the two systems, we evaluate the impact of postponement on the manufacturer under four circumstances. Our results show that postponement strategy can give a lower total average cost under certain circumstances. We also find that the key factors in postponement decisions are the variance of the machine utilization rates and the variance of the backorder costs.     

Confidence intervals for a two-parameter exponential distribution: One- and two-sample problems

The problems of interval estimating the mean, quantiles, and survival probability in a two-parameter exponential distribution are addressed. Distribution function of a pivotal quantity whose percentiles can be used to construct confidence limits for the mean and quantiles is derived. A simple approximate method of finding confidence intervals for the difference between two means and for the difference between two location parameters is also proposed. Monte Carlo evaluation studies indicate that the approximate confidence intervals are accurate even for small samples. The methods are illustrated using two examples.     

保护与建构城市空间文化的对策与途径

中国在快速城市化的步履下,城市空间中的文化遗产破坏、文化畸形、文化贫血现象成为普遍的城市症候.在文化需求、文化活动和文化建设行动急剧增加的形势到来时,相应的规划理论、策略和方法都明显落后于城市建设实践的需要.文章通过城市空间文化的本体述要、城市空间文化的类型学分析和城市空间的文化盘点,深入探讨并提出了保护与建构城市空间文化或文化的城市空间的具体对策和途径.     

Saving for Children’s College Education: An Empirical Analysis of the Trade-off Between the Quality and Quantity of Children

This paper examines the effect of children’s college expenses on household savings. The theoretical model introduces life-cycle savings into the quality–quantity model of fertility and derives predictions for the impact of expected expenses on parents’ savings. Using the actual amount of parents’ financial support reported in the Survey of Consumer Finances, the empirical model estimates the expected expenditures on children’s college education and investigates the effect of expected expenditures on parents’ savings. The results show that parents’ support for each of their children’s college expenses decreases with the number of children. The results are consistent with the predictions of the life-cycle theory of saving and consumption that households save in advance for expected expenses to smooth their consumption.

The quality–quantity trade-off in fertility across parent earnings levels: a test for credit market failure

The dominant economic theory of the family explains the negative correlation between family size and child achievement, a ‘quality–quantity trade-off’, through borrowing constraints and credit market failure. This paper presents a model in which the opportunity cost of time spent with children is increasing, thus creating a trade-off even in economies with perfect credit markets. While both produce a family size effect, temporal and financial constraints predict different patterns for the trade-off across levels of parent income. Using data from the National Child Development Study, the trade-off is found even among high-earning families who presumably do not face credit constraints. Moreover, the trade-off does not grow as parent earnings diminish. Both of these findings suggest that temporal and not financial constraints explain the quality–quantity trade-off.

The supplier selection problem with quantity discounts and truckload shipping

To minimize procurement expenditures both purchasing and transportation costs need to be considered. We study a procurement setting in which a company needs to purchase a number of products from a set of suppliers to satisfy customer demand. The suppliers offer total quantity discounts and transportation costs are based on truckload shipping rates. The goal is to select a set of suppliers so as to satisfy product demand at minimal total costs. The resulting optimization problem is strongly NP-hard. We develop integer programming based heuristics to solve the problem. Extensive computational experiments demonstrate the efficacy of the proposed heuristics and provide insight into the impact of instance characteristics on effective procurement strategies.     

孩子质量与数量选择的理论模型及其应用

以贝克尔的孩子质量与数量选择的理论模型为基本分析工具,深入分析了母亲教育程度的提高会导致孩子质量的提高,而使孩子数量减少;同样,生育孩子的“固定成本”上升会导致有利于孩子质量的替代;最后还解释了为什么随着人们收入水平的提高,出生率反而下降和为什么在传统的农业社会,家庭普遍选择多生多育的生育模式。     

“五普”人口总量和结构的分析与调整

以人口普查资料为基础,运用人口存活分析方法和数值拟合思想,并辅之以其他统计数据和对比分析方法,分析五普数据中的重报和漏报,对普查人口总量和结构进行调整。研究发现,“五普”0-9岁人口存在漏报,漏报人口为3 743万;而10-60岁人口存在重报,重报人口为1 134万人;最终调整五普人口总数为127 120万,普查人口漏报率为2.05%。