我国民航飞行员需求的遗传神经网络预测研究     

王洪佳  赵辉 《黑龙江科技信息》2009,(36):86-87

伴随着中国民航事业的飞速发展,我国民航飞行员的需求规模也开始同步扩大。由于民航飞行员需求预测具有复杂性和非线性的特征,采用神经网络预测方法,并针对神经网络易陷入局部极值的缺陷,采用遗传算法对其进行优化,构造了遗传神经网络算法对其进行预测分析。利用我国民航飞行员需求的实例验证了算法的有效性,为我国飞行员培养提供理论依据。  相似文献   

产业集群的发展轨迹分析   总被引：4，自引：0，他引：4  

戴卫明  肖光华 《湖南科技学院学报》2005,26(1):208-211

本文借鉴种群生态学的理论,建立了产业集群的逻辑斯谛增长模型,并通过对模型中各个参数的分析,总结出影响产业集群发展轨迹的内部和外部因素。文章还对地方政府如何促进产业集群的发展提出了政策建议。  相似文献   

2004中国儿童文学理论批评综述     

王泉根 《湖南科技学院学报》2005,26(10):42-46

2004年是中国儿童文学抓住时机、整合资源、创新奋进的一年.深入探讨儿童文学的社会化推广与应用、进一步加强和深化儿童文学学科建设、“成长小说”研究取得突破、理论批评积极介入当今创作现状、儿童文学史的研究与少数民族儿童文学研究有新的发现和创见,这些重要现象共同构成2004年中国儿童文学理论批评的特色与亮点.  相似文献   

互联互通蓝图下中国产业转型升级与经济中高速增长复杂系统研究     

申慧云  张向前 《科技管理研究》2019,(10)

互联互通是新时代背景下国家区域间实现资源共连的方式,中国产业转型升级是新时代中国产业发展的必然选择,经济中高速增长是新时代中国经济发展的特征体现。借助复杂适应性系统理论,采用“自下而上”的分析思路,首先分析了中国产业转型升级与经济中高速增长系统的主体适应性,接着对上述2个系统在互联互通环境系统下的复杂适应性属性及运作机制进行了分析,在此基础上提出增强主体适应性学习,营造开放包容的系统环境,明晰系统共同体演进方向,确立合理规则集,充分发挥探测器,响应器及辅助系统功能等建议,为中国产业转型升级动力,路径选择和经济中高速增长向高质量方向发展提供了理论借鉴。  相似文献   

创业板上市公司专利态势及问题研究 ——基于创业板六个行业的数据分析     

马碧玉 《科技管理研究》2019,(24)

客观评价创新型中小企业的创新能力是甄别资本市场上以“创新”作为卖点的企业价值的基础,更是制定创新激励政策的必要参考。通过对创业板具有代表性的六个行业的企业专利数据以描述性统计方法进行分析,可以描绘出六个行业中小企业的创新水平基线。从专利数量和专利质量来看,这六个行业间区别明显,各个企业间的差异显著,总体而言专利质量较低。因行业、企业间的差异较大,创新激励措施应更具有针对性而非普惠性;因专利质量总体较低,创新激励措施应更强调创新成果的质量而非数量。  相似文献   

Development of an individualized risk calculator for poor functioning in young people victimized during childhood: A longitudinal cohort study     

《Child abuse & neglect》2019

BackgroundChildhood victimization elevates the average risk of developing functional impairment in adulthood. However, not all victimized children demonstrate poor outcomes. Although research has described factors that confer vulnerability or resilience, it is unknown if this knowledge can be translated to accurately identify the most vulnerable victimized children.ObjectiveTo build and internally validate a risk calculator to identify those victimized children who are most at risk of functional impairment at age 18 years.ParticipantsWe utilized data from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally-representative birth cohort of 2232 UK children born in 1994–95.MethodsVictimization exposure was assessed repeatedly between ages 5 and 12 years along with a range of individual-, family- and community-level predictors. Functional outcomes were assessed at age 18 years. We developed and evaluated a prediction model for psychosocial disadvantage and economic disadvantage using the Least Absolute Shrinkage and Selection Operator (LASSO) regularized regression with nested 10-fold cross-validation.ResultsThe model predicting psychosocial disadvantage following childhood victimization retained 12 of 22 predictors, had an area under the curve (AUC) of 0.65, and was well-calibrated within the range of 40–70% predicted risk. The model predicting economic disadvantage retained 10 of 22 predictors, achieved excellent discrimination (AUC = 0.80), and a high degree of calibration.ConclusionsPrediction modelling techniques can be applied to estimate individual risk for poor functional outcomes in young adulthood following childhood victimization. Such risk prediction tools could potentially assist practitioners to target interventions, which is particularly useful in a context of scarce resources.  相似文献   

Growth orientation predicts gains in middle and high school students’ mathematics outcomes over time     

《Contemporary educational psychology》2019

Academic growth constructs, such as growth mindset and various forms of growth goals, have been of substantial focus in psycho-educational research. Recent research has sought to identify how such growth constructs are inter-related, finding that an underlying growth orientation (comprised of growth mindset, self-based growth goals, and task-based growth goals) was cross-sectionally associated with more positive outcomes for students. However, for such a construct to have meaningful relevance to education and educational research, it must be associated with actual growth in academic outcomes. Accordingly, using two-wave longitudinal structural equation modeling in a large sample of Australian middle and high school students (N = 2949), we examined the extent to which students’ growth orientation predicted growth in academic outcomes. We hypothesized that students’ growth orientation would be positively associated with gains in students’ mathematics engagement and achievement, while controlling for student demographic covariates (e.g., gender, age) and prior variance in each substantive factor measured one year prior. Results demonstrated that students' growth orientation in mathematics was a significant positive predictor of students' gains in mathematics engagement and achievement, above other sources of influence. Findings are discussed in terms of improving researchers’ understanding of how growth constructs are inter-related and how to promote students’ academic success in mathematics.  相似文献   

Biased predictions of students’ future achievement: An experimental study on pre-service teachers’ interpretation of curriculum-based measurement graphs     

《Studies in Educational Evaluation》2018

In an online experiment, a sample of N = 109 pre-service teachers were presented with 14 graphs mimicking graphs used in curriculum-based measurement. Graphs depicted a student’s weekly test scores for the first part of a semester, and participants were instructed to use the graphs to predict students’ achievement at the end of the semester. Relative to a linear regression model, participants generally tended to underestimate future achievement (i.e., predictions were negatively biased). Predictions were more negatively biased when data variability was low rather than high, when improvement was steep rather than flat, and when the most recent score indicated a performance upturn as opposed to downturn. The results are interpreted in the light of models of judgmental anchoring (Kahneman & Tversky, 1973; Mussweiler & Strack, 1999). Implications for practice are discussed.  相似文献   

回归模型中的预测问题     

李小莲 《保山师专学报》2010,29(2):89-91

概率统计在社会的各个领域都有着广泛的应用,尤其是回归模型。对回归模型的预测与控制问题进行了研究。首先介绍了回归模型以及回归模型的预测与控制方法,然后分析了回归模型预测的步骤,最后以企业实例为基础,分别对一元回归模型的预测、二元回归模型的预测进行了分析。  相似文献   

Modeling of growth stress gradient effect on the oxidation rate at high temperature     

Fan Yang  Bin Liu  Dai-ning Fang 《浙江大学学报(A卷英文版)》2010,11(10):789-793

A new oxidation kinetics model is established for high-temperature oxidation. We assume that the interface reaction is fast enough and the oxidation rate is controlled by diffusion process at high temperature. By introducing the growth stress gradient we modify the classical oxidation parabolic law. The modified factor of the oxidation rate constant is a function of growth strain, environment oxygen concentration, and temperature. The modeling results show that the stress gradient effect on the oxidation rate cannot be ignored. Growth strain will dominate whether the stress gradient effect promotes or slows down the oxidation process. The stress gradient effect becomes weaker at higher temperature. This effect is amplified at higher concentrations of environmental oxygen. Applied mechanical loads do not affect the oxidation rate. This model is available for high temperature oxidation of metals and alloys.  相似文献