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131.
INFORMIX数据库系统磁盘I/O性能优化的研究 总被引:2,自引:0,他引:2
胡建荣 《廊坊师范学院学报(自然科学版)》2009,9(4):31-33
研究和探讨了INFORMIX数据库应用系统磁盘I/O性能优化问题,提供了两条优化思路和方法,即把数据优化分布在不同磁盘驱动器上和使关键设备独占关键资源。 相似文献
132.
苏德超 《华中科技大学学报(社会科学版)》2009,23(3)
我的神秘在于:无所不在又无处可寻.早期和中期的维特根斯坦,基于先验的或现象主义的理由,通过消除我来消除这一神秘.后期(包括中后期)的维特根斯坦则认为,我是无法消除的;虽然我们可以从语言使用的角度知道"我"是谁,却无法知道"我"如何指向了我,也不能知道我是谁.维特根斯坦的相关说法可以合理地看成是康德相关论述的语言学继续. 相似文献
133.
D/A转换器是将单片微型计算机送来的数字信号,经转换后变为模拟信号进行输出,DAC0832可以方便地产生各种输出波形,在单片机接口技术中得到了广泛的应用。 相似文献
134.
135.
过去的数字化图书馆和网站的可用性测试通常都集中关注与图形化界面相关的事务以及DL(Digital Library)内部信息的组织,通常忽略了它们在改变工作实践或行为上的作用.本文提出了一种带冲突检测的DL可使用性度量模型CCMM(Conflicting Checked Measuring Model),CCMM在用户使用DL之前采集用户知识水平,并在用户使用DL后对应生成态度改变问题,将用户对这些问题的反应进行FD/I人格特征冲突检测,若未出现冲突,则认为数据真实可靠,可用于DL可使用性度量计算.计算的结果可用于DL优化,最后试验说明CCMM在进行DL可使用性度量上是适用、有效的. 相似文献
136.
董晓佳 《西南师范大学学报(人文社会科学版)》2009,(4):186-189
君士坦丁一世是罗马帝国历史上杰出的政治家,在位期间不仅保护和支持基督教,也对传统的多神教采取宽容政策。他对多神教的宽容是其宗教政策的重要组成部分,是出于实际的政治考虑,是为了达到巩固统治、统一帝国以及维持社会稳定的目的。 相似文献
137.
Critics of school choice argue that cream-skimming will worsen outcomes for those left behind in public schools. Since “high ability” families may have already sorted themselves out of the schools in question, this paper will examine whether existing within-school heterogeneity leaves any scope for cream-skimming to operate. It asks, “given the current level of within-school heterogeneity, how strong would peer effects have to be to significantly worsen outcomes for those left behind?” In order for cream-skimming to lower math test scores by one half-year's progress, the peer effect would have to be as strong as increasing class sizes by 8–20 students, or cutting per-student funding by $400–2000. These results indicate that current levels of within-school heterogeneity are so low that peer effects would have to be unrealistically strong to give cream-skimming any bite. 相似文献
138.
In the U.S., white parents may choose to send their children to private schools in response to the local concentration of minority schoolchildren, commonly referred to as “white flight”. This paper contributes to the existing literature by providing new evidence on white flight from the data set High School and Beyond (HSB). I find that a one-percentage-point increase in the county (metropolitan area, or MA) level minority share of school-age population increases the private schooling probability of white students by 0.2 (0.27) percentage points. White flight appears to be more sensitive to the concentration of black schoolchildren than to any other minority concentration. White families also appear to respond more strongly to the concentration of poor minorities than to non-poor minorities. Results also suggest substantial variation in the rate of white flight across different areas of the country. Finally, when minority shares are measured at the county level, there is some evidence of increasing rate of white flight from the local concentration of black schoolchildren as the black share increases. 相似文献
139.
Research fairly consistently demonstrates that teachers are an important measurable factor in student learning, yet few teacher characteristics are shown to be consistently related to student achievement. Using a state administrative dataset that matches individual students to their teachers over time, I find that math teachers’ undergraduate performance, as measured by GPA (overall, math, and math education) and course hours (math and math education), is predictive of 5th grade math achievement. The effects of the teacher characteristics are mediated by years of experience and vary according to student types. 相似文献
140.
Merit-based financial aid awards have become increasingly prevalent in the pricing policies of higher education institutions. This study utilizes an experiment to estimate the efficacy of merit-aid awards in achieving the institutional objective of attracting the most academically desirable applicants. I find that merit aid has a statistically significant but inelastic effect on enrollment of extremely high ability students. Additionally, the setting of this paper allows for a test of whether students respond to the framing of price in making enrollment decisions (i.e. price illusion), holding net price constant. There is weak evidence in support of price illusion among this set of students. 相似文献