基于混合聚类的城市道路多时段控制研究*

多方案控制具有简单实用、可靠性好,稳定性高,性价比高等的优点,在城市交通控制中得到了广泛应用。本研究在利用指数平滑异同移动平均法对缺失交通数据进行修补的基础上,运用快速聚类与系统聚类相结合的混合聚类方法对交通数据进行分析,并以经典的Silhouttte评价指标作为聚类终止条件,同时兼顾/考虑了交通数据时序性,消除聚类结果中的三类“奇异点”,最后利用交通信号配时软件SYNCHRO制定了相应时段的控制方案。相关的案例分析显示,优化后的多时段控制方案可以更好地适应交通流的波动,车均延误减少9.79%,其中时序性考虑可以有效改善控制方案频繁切换对交通流的扰动,避免其负效应对混合聚类改善效果的影响。     

氰戊菊酯剂型加工研究进展

综述了近年来氰戊菊酯剂型加工研究进展，重点介绍了其混合制剂的发展情况。     

低腐蚀酚醛泡沫及其改性研究

合成了可发性酚醛树脂，确定了酚醛泡沫用低腐蚀性混合酸固化体系的配方及其发泡工艺参数，并采用聚乙二醇、氢氧化铝对其进行了改性，研究了聚乙二醇及氢氧化铝加入量对泡沫压缩强度、阻燃性及发泡工艺等的影响。     

高性能混凝土配合比设计的试验研究

从对HPC组成、结构的认识出发，借鉴利用拨开系数求砂率的方法，提出了一种新的HPC配制方法，并通过试验证实该方法是完全可行的．     

遗传算法在混合H_2/H_∞优化控制设计中的应用

介绍了现已成为关键智能计算之一的一种新的全局优化搜索算法—遗传算法，并探讨了在混合Ｈ２／Ｈ∞最优指标下优化控制设计中的应用。其最大特点是：本质并行、全局优化，它不要求目标函数连续和可微，比梯度法和随机搜索算法更适合于ＰＩＤ混合Ｈ２／Ｈ∞优化问题。     

用广义上界算法解大型供应链问题

信息技术和生产率的发展以及全球经济一体化的发展趋势，使供应链成为全世界管理科学的热点.本文在阐述供应链基本数学模型的基础上，系统论述了用改进的广义上界(GUB)算法求解大型供应链问题的计算方法．     

Hydrothermal Synthesis and Crystal Structure of a New Dimeric Lanthanum(Ⅲ) Complex

A new dimeric lanthanum(Ⅲ) complex [La2(phen)2(C7H3N2O6)6](phen=1,10-phenanthroline) was synthesized by the hydrothermal method and determined by single crystal X-ray diffraction analysis. The La(Ⅲ) ion is coordinated to seven oxygen atoms from five carboxylate groups and two nitrogen atoms from a phen ligand,forming a monocapped square antiprismatic geometry. Six carboxylate groups coordinate to two La(Ⅲ) ions in three modes which are chelating bidentate,bridging bidentate and bridging tridentate. The crystal is triclinic with space group P-1,a=1.2030(4) nm,b=1.2962(5) nm,c=1.3330(5) nm,α=104.410(5)°,β=114.048(4)°,γ＝100.054(4)°,V=1.7467(10) nm3,Mr=952.46,Z=2,Dc=1.811 g·cm-3,F(000)=944,S=1.017,μ=1.320 mm-1,with R1=0.0298 and wR2=0.0625.     

混粉电火花加工在模具制造中的应用

通过对混粉电火花加工工艺与传统模具制造工艺的比较，从混粉电火花加工工艺的机理、表面特性、影响因素等各方面来阐述，混粉电火花加工是生产高精度、高寿命、效率的模具的最有效的工艺之一。     

水泥土搅拌桩加固软土地基实例分析

本通过工程实例说明，位于稳定水位以下的土体采用水泥土搅拌桩进行加固应优先采用干法作业，而不宜采用湿法作业。     

Academic trajectories of newcomer immigrant youth.

Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve analysis revealed that although some newcomer students performed at high or improving levels over time, others showed diminishing performance. Multinomial logistic regressions identified significant group differences in academic trajectories, particularly between the high-achieving youth and the other groups. In keeping with ecological–developmental and stage–environment fit theories, School Characteristics (school segregation rate, school poverty rate, and student perceptions of school violence), Family Characteristics (maternal education, parental employment, and household structure), and Individual Characteristics (academic English proficiency, academic engagement, psychological symptoms, gender, and 2 age-related risk factors, number of school transitions and being overaged for grade placement) were associated with different trajectories of academic performance. A series of case studies triangulate many of the quantitative findings as well as illuminate patterns that were not detected in the quantitative data. Thus, the mixed-methods approach sheds light on the cumulative developmental challenges that immigrant students face as they adjust to their new educational settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)