城镇化视角下的新生代农民工置业定居选择

我国现代化基本路径是城镇化,而其中最迫切和最重要的是实现新生代农民工的城镇化。基于老年父母的抚养、子女入学、文化认同及其社会身份获得等多种因素的考量,返回户籍地城镇置业安居成为新生代农民工城镇化的主要选择。在城镇化的推进过程中,应从历史和现实出发,尊重新生代农民工的这种主体性选择,将新生代农民工返乡置业纳入到城镇化的规划和发展思路上来,合理引导新生代农民工在老家中小城镇置业、定居,并为新生代农民工在老家中小城镇置业、定居提供制度性的保障。     

变拓扑机构可变运动副设计目录研究

可变运动副作为变拓扑机构改变拓扑结构的关键所在,其结构设计是变拓扑机构构型综合的难点.基于可变运动副拓扑变化方式的研究,构建可变运动副设计目录,用于可变运动副的结构设计.分别针对可变运动副的改变轴线方位、改变数目和改变类型等三类拓扑变化过程,分析可变运动副的约束变化特征,并采用运动副约束函数的算术运算进行描述.在归纳设计可变运动副结构形式的基础上,对可变运动副拓扑变化方式、约束变化特征和对应结构等设计信息进行分类和汇编,构建可变运动副设计目录.应用实例表明,采用可变运动副设计目录,能快速有效地设计可变运动副结构,为含可变运动副的变拓扑机构构型综合提供了方便.     

面向历史轨迹的多因素驾驶偏好挖掘算法

提出一种新型基于窗口的数据挖掘算法,以用来挖掘所定义的多因素驾驶偏好.具体地,定义了多因素之间的两两权衡来刻画驾驶偏好;提出了一种用于估算偏好分布的挖掘算法,并根据假设引入了椭圆对挖掘算法进行了优化.结果证明,该方法能够发现本文所定义的多因素驾驶偏好,并且算法有效、快速,具有较好的扩展性.     

基于目标导向的多属性决策属性价值公度方法

MACBETH方法在多个属性维度上确定出的一组属性Good值(或Neutral值)并不能真地具有保证属性价值公度的完全相同的偏好涵义.为克服该方法缺陷,基于包容性属性价值函数,通过引入数据包络分析技术和马尔可夫理论给出了以目标参照方案为导向的目标导向属性价值函数和多属性决策属性价值公度的方法程序.相比于具有较大随意性确定属性Good值和Neutral值的MACBETH方法,依赖目标导向属性价值函数的多属性决策属性价值公度程序具有更明显的科学合理性,因此具有发展MACBETH方法,推动实际决策应用该方法及相关多属性偏好关联决策模型的创新价值.基于决策实验的应用分析直接验证了多属性决策属性价值公度方法程序的科学有效性,间接验证了包容性属性价值函数和目标导向属性价值函数的科学理性.     

Butterflies (Lepidoptera: Papilionoidea) of Mount Kilimanjaro: Nymphalidae subfamilies Libytheinae,Danainae, Satyrinae and Charaxinae

This paper, which presents an annotated checklist of the ‘lower Nymphalidae’ (Libytheinae, Danainae, Satyrinae, Charaxinae), is the fourth in a series on the butterfly fauna of Mount Kilimanjaro. Four genera of lower Nymphalidae (Danaus, Amauris, Bicyclus, Charaxes), with a total of 11 included species, are known or believed to occur within the main forest zone, from c. 1800 to 2800 m. Of these, only three species of Charaxes (Charaxes berkeleyi, Charaxes ansorgei, Charaxes xiphares) may be restricted locally to this primary forest. The lower slopes fauna, below 1800 m, is considerably richer, with a total of 11 genera and 41 species listed (8 species of which extend into the forest zone). Possible additional species, dubious earlier records, problems with African subspecies of Danaus chrysippus, a need for more work on certain Satyrinae, and classification of the genus Charaxes are discussed. An identification key to the subfamilies of Nymphalidae, and the 19 genera of Libytheinae, Danainae, Satyrinae, Charaxinae that occur in Tanzania, together with a key to the adults of all the species of these four subfamilies considered to occur or have occurred on Kilimanjaro, with 206 colour images, are included as online Supplementary Information.     

和而不同:英语中的中国因素

中国从19世纪初到现在接触和使用英语已有近两百年的历史,由于中西文化的相互影响和渗透,许多汉语的词汇逐渐进入英语,成为英语的一部分。中国英语以英国英语为核心,但有着鲜明的中国特色。本文拟从语言变异:中国因素的融入根源、顺应理论:验证中国因素的表现特色、英语全球化、本土化:引导中国因素的发展趋势三个方面阐释英语中的中国因素。     

基于聚类方法和神经网络的非线性系统多模型自适应控制

针对具有参数跳变的非线性系统,联合聚类算法和神经网络提出新的多模型自适应控制方法。首先对系统的输入输出数据进行模糊聚类,然后基于递推最小二乘法建立多个固定模型。为提高系统的暂态性能,同时建立两个自适应模型,并在此基础上设计鲁棒自适应控制器。此外,为了补偿系统的非线性部分,建立非线性预测模型,并设计非线性神经网络自适应控制器。所提方法可使控制切换系统具有稳定性保证。最后,通过性能指标对控制器进行平滑切换。仿真结果表明,所提方法能够保证系统具有良好的控制性能。     

Reproductive ecology of the glass frog Espadarana prosoblepon (Anura: Centrolenidae) in an urban forest of the Central Andes of Colombia

Population and reproductive behaviour aspects of the glass frog Espadarana prosoblepon are well known for populations from Central America, but similar information is lacking for populations from South America. We recorded the reproductive ecology of a population of the glass frog E. prosoblepon in the city of Armenia, Central Andes of Colombia. With weekly surveys with mark-recapture between December 2013 and November 2015, we monitored activity patterns and evaluated if the probability of males mating is associated to their body size or to chorus tenure (i.e. the number of nights a same individual is calling for attracting a mate). In addition, upon observing an amplexus, we recorded the behaviour of the individuals until oviposition and noted characteristics of egg clutch. We recorded 47 males and 32 females, nine amplexus events, eight ovipositions, and 21 egg clutches (35.4 ± 4.79 eggs per clutch, N = 29). Activity of males and females and the number of egg clutches were positively correlated to rainfall. Mating success of males was not associated to their body size, but it was positively associated to longer chorus tenure; clutches from large females had a higher number of eggs than clutches from small females. Oviposition occurred on average 3.76 ± 1.74 hours after we first observed the amplexus, occurring 93.1% of the time in fronds of Selaginella geniculata at an average height of 1.58 ± 0.44 m. After the oviposition, the male left the site, while the female remained between 30 and 45 min, partially covering the eggs. The reproductive behaviour of E. prosoblepon did not vary widely between a population in Costa Rica and our population in time to oviposition, and mating success of males associated to chorus tenure; however, in our study population we recorded a larger clutch size and the preference for S. geniculata fronds as oviposition substrate.     

Diet comparison between rainforest and cave populations of Craugastor alfredi (Anura: Craugastoridae): does diet vary in contrasting habitats?

Information about interpopulational variation of diet is important for thoroughly understanding the ecological niche of a species, the possible attributes that have allowed it to live in different habitats and ecosystems (if it is the case) and the degree of dietary specialization. This study compared dietary composition and diversity, size of prey consumed and feeding intensity between two geographically proximate populations of Craugastor alfredi, inhabiting contrasting habitats: one located in a remnant tropical rainforest and the other population located within a cave entrance, in eastern Mexico. A total of 118 frogs (50 from rainforest and 68 from cave) were stomach-flushed and, from those, 86 had at least one prey item (42 from rainforest and 44 from cave). Consumption proportions of orthopterans differed between habitats, with frogs from the cave having higher importance values of this prey than frogs from the rainforest. Additionally, both dietary diversity and feeding intensity were higher in the rainforest population. It was concluded that the generalized diet of C. alfredi, besides the high consumption of orthopterans by the cave population, may have contributed to its success in cave entrances. Nonetheless, other non-feeding attributes like small body size, direct development and semiarboreality may also facilitate the use of rock crevices in caves for foraging and reproduction.