一类n阶高次微分方程的特解

在复数域内,利用特征方程的特征根给出了一类n阶常系数高次微分方程求特解的方法,推广了已有文献的结果.     

基于复杂网络和粒子群算法的滤波与轨道优化模型

嫦娥三号已成功完成软着陆,其着陆准备轨道的位置和着陆轨道及其控制策略是嫦娥三号月球着陆的关键问题。运用天体物理相关理论及智能优化算法构建了基于复杂网络的滤波模型和基于粒子群算法的着陆轨道优化模型,并通过matlab计算及matlab仿真,给出了着陆轨道及其控制策略。     

Development of learning to learn skills in primary school

In Finland, schools’ effectiveness in fostering the development of transversal skills is evaluated through large-scale learning to learn (LTL) assessments. This article presents how LTL skills—general cognitive competences and learning-related motivational beliefs—develop during primary school and how they predict pupils’ CPS skills at the end of sixth grade. The six-year follow-up of 608 pupils shows that cognitive competences demonstrated in the beginning of the first grade in a learning preparedness test predict both later cognitive LTL competences and CPS, but their development is not fully determined by earlier individual differences in learning preparedness in the first grade. Motivational beliefs begin to be related to cognitive LTL performance gradually from age 10 on, and they may have a slightly stronger effect on CPS than on cognitive LTL performance. It is concluded that the development of CPS is partly depending on pupils’ initial learning preparedness and the development of their LTL skills.     

国外海岸带韧性研究进展及其对中国的启示

海岸带韧性可为沿海地区应对全球气候变化与人类活动压力的复合风险提供新的理论源泉和分析视角,对保障沿海地区可持续发展安全具有重要意义.本文在解析海岸带韧性概念内涵的基础上,剖析了以社会生态系统、复杂适应系统等理论为支撑的海岸带韧性理论框架,比较了现有4类评价方法,进而厘清了要素型、过程型和复合型3类评价指标体系的特点,阐...     

Why do students strive to outperform classmates? Unpacking their reasons for pursuing performance goals

Achievement goal theory has evolved since introduced about 40 years ago. One of its newer variants is the goal complex model. It assumes that each achievement goal (i.e., performance or mastery) can be pursued for many reasons and, more provocatively, that the goal’s effects depend partly on why it is pursued. Clearly, the first task for this area is to identify likely goal pursuit reasons, develop and validate a measure of reasons, and chart the influence of those reasons. Progress remains limited, however. Nearly all studies have considered only a small set of reasons suggested predominantly by self-determination theory, overlooking several other plausible reasons. Nor is there an established measure of goal pursuit reasons. To overcome those limitations, the current study validated and tested a new goal complex measure that includes several additional goal pursuit reasons, both personal (e.g., pride) and social (e.g., to make close others proud, or to help or serve others) in nature. Two culturally distinct samples of university students – one from the USA (n = 400), the other from Thailand (n = 404) – completed the measure with performance goals in mind and then reported a diverse array of educational outcomes. Their results converge for the most part. In each sample, the new measure proved to have good structural validity and psychometric properties. Several goal complexes, including the new social ones, showed unique and often desirable relationships with outcomes, too. The findings raise several research directions and implications for achievement goal theory.     

复杂产品系统研发项目合作伙伴选择优化

合理选择合作伙伴是复杂产品系统研发项目的关键成功因素之一。在对伙伴选择影响因素进行总结的基础上,选取费用、时间、风险及合作伙伴间的协作关系作为主要考虑因素,建立了复杂产品系统研发项目伙伴选择的多目标整数规划模型。该模型旨在为各子项目找到整体最佳的合作伙伴组合,以实现总项目失败风险最小化和总项目费用与拖期惩罚最小化。设计了遗传算法用于求解该伙伴选择数学模型,并通过实际案例证实了该模型的实用性和算法的有效性。     

干系人私人关系、知识共享行为对复杂产品研发绩效的影响

在文献回顾的基础上,提出了干系人私人关系的三个构成:感情、人情和面子,探讨了干系人私人关系的三个构面、知识共享行为和复杂产品研发绩效之间的关系,构建了理论模型,并以复杂产品研发团队的干系人为调查对象对模型进行了实证研究。研究结果显示:干系人的感情、人情和面子均对知识共享行为有显著的正面影响,感情和面子对复杂产品研发绩效有显著正面影响,知识共享行为对复杂产品研发绩效有显著正面影响。此外,研究结果还表明,知识共享行为在人情和复杂产品研发绩效之间起到了完全中介作用;知识共享行为在感情和复杂产品研发绩效及面子和复杂产品研发绩效之间分别起到了部分中介作用。     

基于检错码静默补偿的跨层链路复激活算法

有效的链路层的复激活算法可以提高语义系统的检错性能。传统方法采用自适应模式匹配方法实现语义系统的跨层链路复激活,当检错码冗余数据块随机放置时,不能有效实现语义检错。提出一种基于检错码静默补偿的跨层链路复激活算法,构建语义系统网络控制模型,设计检错码编码数据块放置方法,提出检错码静默补偿机制并实现跨层链路复激活算法改进。实验结果表明,采用该算法能有效实现语义系统检错码跨层链路激活,谱峰复激活搜索明显,任务执行精度提高17%,算法在语义网通信编码设计等领域具有较好的应用价值。     

锌(Ⅱ)离子为中心的三元配合物的水热合成及晶体结构

通过水热反应,合成了一种2-(4-吡啶基)-苯并咪唑、对硝基苯甲酸及锌(Ⅱ)三元配合物.并对该配合物的结构进行了测定,发现该配合物属于三斜晶系,P-1点群,晶胞参数为a=0.7902(8)nm,b=1.3277(13)nm,c=1.7837(17)nm;α=99.953°(18),β=94.666°(16),γ=90.354°(16).每个锌离子周围有两个对硝基苯甲酸及两个2-(4-吡啶基)-苯并咪唑;其中两个对硝基苯甲酸分别以一个羧基氧原子,两个2-(4-吡啶基)-苯并咪唑分别以吡啶环上的氮原子和锌离子中配位,形成四面体结构.     

科研人员省际流动网络分析及演化过程研究

   本文基于“科学家在线”平台数据,运用复杂网络分析方法,按照年份分别构建2010—2017年间全国34个省份之间科研人员流动网络模型,测度并分析8年间科研人员流动的复杂性网络整体特征和随时间变化的趋势。研究发现：（1）8年间科研人员流动呈现整体较为明显的“无标度”特性,即北京、上海、江苏等经济科技发达地区不仅流入科研人员的规模较大,流出科研人员的规模也不小,但是全国大部分省份流动科研人员规模较为有限;（2）除了小部分省份之外其余省份的人员流入流出相对较为均衡,一些经济科技发达省份在一定程度上也是全国或本区域科研人员流动的中心节点;（3）从发展态势来看,8年间全国省级科技人员流动态势相对平稳,但是省份之间科研人员流动规模差距越来越明显,经济科技发达省份与其他省份科研人员流动的规模相比差距越来越大;（4）最为突出的变化是流动人员规模显著增加,人员流动更加便利。