{X,Y}-Cyclacene Graphs with Next Nearest Neighbor Interactions

Eigensolutions of {X( = C,B,N),Y( = C,B,N)}-cyclacene graphs with next nearest neighbor (nnn) interactions have been obtained in analytical forms by adapting n-fold rotational symmetry followed by two-fold rotational symmetry (or a plane of symmetry). Expressions of eigensolution indicate the subspectral relationship among such cyclacenes with an even number of hexagonal rings e.g., eigenvalues of {X,Y}-di-cyclacene are found in the eigenspectra of all such even cyclacenes. Total π-electron energies and highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) gaps are calculated using the analytical expressions obtained and are found to vary negligibly with the variation of nnn interactions in such cyclacenes. Total π-electron energy is found to increase due to increase in restriction intensity of nnn interactions, whereas the HOMO–LUMO gap of polyacenecs having the even number of hexagonal rings and with one electron at each site (atom) decreases with increase in the restriction intensity since such systems contain degenerate half-filled HOMO (bonding or nonbonding) that are much more vulnerable for perturbations imposed through nnn interactions.     

基于最近邻与神经网络融合模型的软测量建模方法

软测量建模能够有效地解决生产过程中在线分析仪表测量滞后大、价格昂贵、维护保养复杂等问题。目前，基于数据驱动的神经网络是软测量建模的主要工具之一。而在建模数据的采集过程中，主导变量的采集相对辅助变量要困难得多，由此产生了大量缺失标签的数据。但传统的软测量建模方法却忽视了这些无标签数据，只利用少量的有标签数据建模，从而影响了模型的预测精度。为了解决标签缺失的问题，采用最近邻算法对无标签数据进行伪标记，同时设计了由卷积操作与门限循环单元神经网络（GRU）结合的网络结构来进一步利用无标签数据，提取不同时刻数据中的动态特征，提高神经网络的预测精度。最后将该方法应用于丙烯精馏塔塔顶丙烷浓度的预测，实验结果表明该模型能有效处理非线性动态系统的标签缺失问题，具有更高的预测精度。     

Use of multiple modes of flight subsidy by a soaring terrestrial bird,the golden eagle Aquila chrysaetos,when on migration

Large birds regularly use updrafts to subsidize flight. Although most research on soaring bird flight has focused on use of thermal updrafts, there is evidence suggesting that many species are likely to use multiple modes of subsidy. We tested the degree to which a large soaring species uses multiple modes of subsidy to provide insights into the decision-making that underlies flight behaviour. We statistically classified more than 22 000 global positioning satellite–global system for mobile communications telemetry points collected at 30-s intervals to identify the type of subsidized flight used by 32 migrating golden eagles during spring in eastern North America. Eagles used subsidized flight on 87% of their journey. They spent 41.9% ± 1.5 (, range: 18–56%) of their subsidized northbound migration using thermal soaring, 45.2% ± 2.1 (12–65%) of time gliding between thermals, and 12.9% ± 2.2 (1–55%) of time using orographic updrafts. Golden eagles responded to the variable local-scale meteorological events they encountered by switching flight behaviour to take advantage of multiple modes of subsidy. Orographic soaring occurred more frequently in morning and evening, earlier in the migration season, and when crosswinds and tail winds were greatest. Switching between flight modes allowed migration for relatively longer periods each day and frequent switching behaviour has implications for a better understanding of avian flight behaviour and of the evolution of use of subsidy in flight.     

Data-oriented multi-index Hashing

The multi-index hashing (MIH) is the state-of-the-art method for indexing binary codes. However, it is based on the dataset codes uniform distribution assumption, and will lower efficiency in dealing with non-uniformly distributed codes. In this paper, we propose a data-oriented multi-index hashing method. We first compute the correlations between bits and learn adaptive projection vector for each binary substring. Then, instead of using substrings as direct indices into hash tables, we project them with corresponding projection vectors to generate new indices. With adaptive projection, the indices in each hash table are nearly uniformly distributed. Besides, we put forward an entropy based measurement to evaluate the distribution of data items in each hash table. Experiments conducted on reference large scale datasets show that compared to the MIH the time performance of our method can be 36.9％～87.4％ better .     

Density estimates on the unit simplex and calculation of the mode of a sample

This paper addresses reliable and efficient calculation of the mode of a multivariate sample, which is a classical fusion function. In particular, we focus on the inputs given on the unit simplex, when aggregating elements of Atanassov intuitionistic fuzzy sets, interval-valued fuzzy sets and their extensions, as well as compositional data. We outline the use of a specially designed 2-additive fuzzy measures and the Choquet integral for the purposes of reducing computational complexity in higher dimensions. We present computational analysis and benchmark four different methods of density-based mode estimation.     

基于模糊数学的"快速递减加权式"在比较法评估房地产价格中的应用研究

本文将模糊数学运用于房地产估价中,引进了贴近度、择近原则的概念,建立了“快速递减加权式”,并运用实例,很好地解决了比较法评估房地产价格时的二大难题:一是如何选择与待估房地产条件相似的交易实例并进行因素差异的量化修正;二是计算出各交易实例的修正价格后,如何确定待估房地产的价格。在国内外,至今尚未发现对此有全面系统地研究,该方法对大宗房地产价格的评估具有广泛的推广应用价值。     

基于改进冒泡排序的模块化多电平换流器电容电压均衡策略

模块化多电平换流器(Modular Multilevel Converter, MMC)子模块电容电压均衡是当前MMC研究领域的热点问题。当MMC的单个桥臂子模块数量较多时,存在控制器运算时间长、子模块投切频繁和开关损耗大并导致MMC故障等缺陷。针对上述缺陷,提出了一种基于改进冒泡排序算法和平均值法混合控制策略。通过实时监测电容电压,采用改进冒泡法在初始化时对子模块电容电压进行排序,减少MMC控制器的运算量。在之后的控制周期采用已投入子模块平均值比较法对子模块作投切,降低开关频率。最后在Matlab/Simulink搭建21电平MMC模型,仿真结果验证了所提混合控制策略的有效性和正确性。     

On information and communication technology and production cost in construction industry: evidence from the Netherlands

The interplay between information and communication technology (ICT) and the competitiveness of construction firms is considered. More specifically, the question is whether firms that invest in information and communication technology have a production cost advantage. The economics literature hypothesizes that ICT brings about a production cost advantage, as ICT brings flexibility and improves the planning, organization and control of work. To test this proposition for the construction industry, a production cost function allowing for the inclusion of ICT is formulated. Using statistical nearest-neighbour matching methods it is possible to identify the effect of ICT on production costs thereby controlling for economic moderators. Data from a sample of Dutch construction firms reveal that those firms that installed ICT capital do have a production cost advantage. The results indicate further that firms need a minimum level of ICT capital to fully benefit from its production cost advantage.     

基于线性最优的MMC子模块电容电压均衡控制策略

为进一步优化模块化多电平换流器(MMC)子模块控制策略,尤其是能够兼顾子模块电容电压波动、桥臂环流二次谐波含量、子模块绝缘栅双极型晶体管(IGBT)投切次数和算法计算量四方面的性能,提出一种基于线性最优解的MMC子模块电容电压均衡控制策略。首先,阐述了子模块电容电压波动和子模块IGBT投切次数之间的相悖性,通过理论分析证明子模块电容电压波动与桥臂环流二次谐波含量之间也存在非线性关系,需寻找适当算法使其三者同时达到最优情况。然后,针对此目标,对传统算法进行优化,增加附加调节子模块功能,并结合子模块电容电压均衡控制策略,详细阐述了所述算法的控制流程及其优越性。最后,通过动模试验对传统控制策略、子模块电容电压均衡控制策略、所提控制策略及其他采用不同数量的附加调节子模块的控制策略进行对比。试验数据表明,所提策略可以在子模块电压波动、桥臂环流中的二次谐波含量和子模块IGBT投切次数三方面达到线性最优。