基于Jaccard相似度和位置行为的协同过滤推荐算法

协同过滤是现今推荐系统中应用最为成功且最广泛的推荐方法之一,其中概率矩阵分解算法作为一类重要的协同过滤方式,能够通过学习低维的近似矩阵进行推荐。然而,传统的协同过滤推荐算法在推荐过程中只利用用户-项目评分信息,忽略了用户(项目)间的潜在影响力,影响了推荐精度。针对上述问题,首先利用Jaccard相似度对用户(项目)做预处理,而后通过用户(项目)间的位置信息挖掘出其间的潜在影响力,成功找到最近邻居集合;最后将该邻居集合融合到基于概率矩阵分解的协同过滤推荐算法中。实验证明该算法较传统的协同过滤推荐算法能够更有效地预测用户的实际评分,提高了推荐效果。

基于小世界网络的用户位置行为兴趣模型

移动智能终端的快速发展为用户的位置服务提供了新的应用,以用户位置行为分析为核心的服务技术具有重要的商业应用价值。用户位置及其活动特点和趋势与其所在位置的实际状况及本人意愿密切联系,用户所在位置的资源和状况信息直接影响了用户的位置行为。本文引入小世界网络模型分析用户的位置行为特征,发现用户基于位置的行为属性和聚类。采用推荐度计算方法描述结点之间的相似性,通过将用户位置作为一个树根,把位置资源作为用户的兴趣结点,将兴趣搜索转换为最短路径计算问题。通过改进的最短路径算法计算根结点到各个结点的推荐度,分析用户最感兴趣的位置资源结点。实验结果表明,采用该方法建立的用户位置行为兴趣模型能够很好地描述用户基于位置的兴趣和意愿,算法在结果精度和计算时间上都具有良好的性能。

非人灵长类位置行为的辐射适应与研究进展

野生动物在长期进化中形成特定的行为模式以适应特定的生存环境。灵长类的位置行为研究对于理解灵长类进化、适应性的多样化以及生态学和解剖学十分关键。该文对已有文献进行了综述,针对位置行为的分类、季节性、以及具体地点和年龄性别差异性进行了总结,分析了灵长类位置行为的发展、特征以及研究现状,以期对今后非人灵长类位置行为的研究提供借鉴和参考,从而促进我国灵长类行为生态学理论体系的发展。

位置敏感语法的三类主要敏感位置

位置敏感语法是互动语言学领域富有影响力的语法观,但言谈互动中究竟有哪些敏感位置?尚需进一步厘清。本文在现有研究的基础上,做进一步探讨,将互动中的敏感位置分为三大基本类型:1)话轮序列类位置,包括TCU位置、话轮位置、序列位置;2)身体活动类位置,包括TCU和话轮参照位置、序列参照位置;3)行为进程类位置,包括行为进程位置、行为调适位置。会话中,语言资源和身体活动资源的选择往往要考虑位置因素,不同的敏感位置上,其互动功能也不尽相同。

灵长类动物位置行为及支持物选择

灵长类动物是高度树栖的动物类群,在适应树栖生活的过程中不断面临着来自外界环境和身体结构的挑战。对灵长类动物位置行为和支持物选择的研究有助于阐明物种形态、行为和环境之间的关系,有助于理解灵长类进化、适应性的多样化以及生态学和解剖学特征。在已有研究的基础上,介绍了灵长类动物位置行为研究中最常用的相关定义与描述,并从生理因素和生态因素两个方面对影响灵长类动物的位置行为及其对支持物选择的因素进行了探讨,以期对灵长类动物位置行为和支持物选择的研究提供参考,并促进国内灵长类动物行为生态学理论体系的发展。

基于一维卷积神经网络的物联网终端非干扰身份识别方法

针对物联网终端身份识别过程易受干扰的问题,设计了基于一维卷积神经网络的物联网终端非干扰身份识别方法.通过物联网终端内置的加速度传感器收集不同步态的加速度数据,并采用平滑与分窗处理进行预处理.利用步态数据融合模型分析用户在不同行为位置组合下的数据,再利用随机森林模型预测物联网终端的位置与用户行为.将行为与位置数据融合,得到步态融合数据,再将融合数据输入至构建的一维卷积神经网络模型中,经过迭代训练后输出用户的身份识别结果.实验结果显示,基于一维卷积神经网络的物联网终端非干扰身份识别方法在合适的模型参数条件下能够准确识别物联网终端用户身份.

Vigilance behavior of Pyrenean chamois Rupicapra pyrenaica pyrenaica:Effect of sex and position in the herd

The Pyrenean chamois Rupicapra pyrenaica pyrenaica is a mountain-dwelling ungulate with an extensive presence in open areas. Optimal group size results from the trade off between advantages （a reduction in the risk of predation） and disadvantages （competition between members of the herd） of group living. In addition, advantages and disadvantages of group living may vary depending on the position of each individual within the herd. Our objective was to study the effect of central vs. peripheral position in the herd on feeding and vigilance behavior in male and female Pyrenean chamois and to ascertain if a group size effect existed. We used focal animal sampling and recorded social interactions when a focal animal was involved. With males, vigilance rate was higher in the central part of the group than at the periphery, probably due to a higher density of animals in the central part of the herd and a higher probability of being disturbed by conspecifics. With females, vigilance rate did not differ according to position in the herd. Females spent more time feeding than males, and males showed a higher frequency of the vigilance behavior than females. We did not observe a clear relationship between group size and vigilance behavior. The differences in vigilance behavior might be due to social interactions

Effect of different quenching processes following solid-solution treatment on properties and precipitation behaviors of 7050 alloy

The effects of quenching in different ways following solid-solution treatment on properties and precipitation behaviors of7050 alloy were investigated by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, selected areaelectron diffraction （SAED）, hardness and electrical conductivity tests. Results show that after quenching in different ways, electricalconductivity of the alloy decreases rapidly in the first 48 h of natural aging. The electrical conductivity of 7050 alloy in natural agingstate is determined by the size and density of GP zones, and the size of GP zones is the main factor. After natural aging for 70 d, thesize of GP zones is 1.8-2.6 nm in matrix of the immersion quenched sample and it is 1.4-1.8 nm in matrix of both water mist andforced air quenched samples. After natural and artificial peak aging, the hardness of the water mist quenched sample is HV 193.6 andits electrical conductivity is 30.5% （IACS） which are both higher than those of the immersion quenched sample. Therefore, watermist quenching is an ideal quenching method for 7050 alloy sheets after solid-solution treatment.

Recent progress on apparatus development and in situ observation of metal solidification processes via synchrotron radiation X-ray imaging: A review

The solidification process of metals plays a critical role in their final microstructure and, correspondingly, in their performance. It is therefore important to probe the solidification behavior of metals using advanced in situ techniques. Synchrotron radiation X-ray imaging is one of the most powerful techniques to observe the solidification process of metals directly. Here, we review the development of the solidification apparatus, including the directional solidification device, resistance furnace, multi-field coupling device, semisolid forming device, aerodynamic levitation apparatus, and laser additive manufacturing apparatus. We highlight the recent research progress on the use of synchrotron radiation X-ray imaging to reveal the solidification behavior of metals in the above circumstances. The future perspectives of synchrotron radiation X-ray imaging in metal research are discussed. Further development of this technique will contribute to improve the understanding of the solidification process of metals and other types of materials at different scales.

CAPTURING COMPLEX,NON-LINEAR TEAM BEHAVIOURS DURING COMPETITIVE FOOTBALL PERFORMANCE

This study investigated changes in the complexity （magnitude and structure of variability） of the collective behaviours of association football teams during competitive performance. Raw positional data from an entire competitive match between two professional teams were obtained with the ProZone tracking system. Five compound positional variables were used to investigate the collective patterns of performance of each team including： surface and geometrical centre. Analyses involve the coefficient （ApEn）, as well as the linear association between both area, stretch index, team length, team width, of variation （%CV） and approximate entropy parameters. Collective measures successfully captured the idiosyncratic behaviours of each team and their variations across the six time periods of the match. Key events such as goals scored and game breaks （such as half time and full time） seemed to influence the collective patterns of performance. While ApEn values significantly decreased during each half, the %CV increased. Teams seem to become more regular and predictable, but with increased magnitudes of variation in their organisational shape over the natural course of a match.

Effect of Pingan Fang, a Traditional Chinese Medicine compound, on behavioral sensitization and conditioned place preference induced by ethanol in mice

OBJECTIVE:To observe the effect of Pingan Fang(PG)on behavioral sensitization and conditioned place preference(CPP)induced by ethanol in mice,and to determine the intervention mechanism of PG on alcohol addiction.METHODS:A behavioral sensitization mouse model induced by ethanol was established to observe the effect of PG on the development and expression of behavioral sensitization induced by ethanol by recording the spontaneous activity of mice.The resident time of mice in a white box was measured to evaluate the effect of PG on developing CPP induced by ethanol.Concentrations of dopamine(DA),Glutamate(Glu),and?-aminobutyric acid(GABA)in the corresponding mesolimbic region of mice were determined by enzyme-linked immunosorbent assay.RESULTS:Although PG did not alter spontaneous activity in mice,it reduced the growth of spontaneous activity stimulated by ethanol.The residence time in the white box after-ethanol-training of mice in CPP experiments was decreased.CONCLUSION:Our data suggested that PG blocked the development and expression of behavioral sensitization induced by ethanol and the development of CPP in mice.The mechanism might be related to the decreased content of DA and Glu and increased content of GABA in the mesolimbic dopamine system.This suggests that PG might be useful for the prevention and treatment of alcohol addiction.

Dynamics of Nonautonomous Dark Solitons

We solve a generalized nonautonomous nonlinear Schrodinger equation analytically by performing the Hirota＇s bilinearization method. The precise expression of a parameter e, which provides a compatibility condition and dark soliton management, is obtained. Comparing with nonautonomous bright soliton, we find that the gain parameter affects both the background and the valley of dark soliton （∈2 ≠ 1） while it has no effects on the wave central position. Moreover, the precise expressions of a nonautonomous black soliton＇s （∈2 = 1） width, background and the trajectory of its wave central, which describe the dynamic behavior of soliton＇s evolution, are investigated analytically. Finally, the stability of the dark soliton solution is demonstrated numerically. It is shown that the main characteristic of the dark solitons keeps unchanged under a slight perturbation in the compatibility condition.

ANALYSES OF LOCATION-PRICE GAME ON NETWORKS WITH STOCHASTIC CUSTOMER BEHAVIOR AND ITS HEURISTIC ALGORITHM

In this paper,a two-stage model is developed to investigate the location strategy andthe commodity pricing strategy for a retail firm that wants to enter a spatial market with multiplecompetitive facilities,where a competitor firm is already operating as a monopoly with several outlets.Expected market shares are calculated based on the stochastic customer behavior on networks.Theauthors provide a sufficient condition for the existence of equilibrium prices in the price game for thefirst time.The existence and uniqueness of the pure strategy Nash equilibrium price with a specifiedutility function are proved in the subgame.A metaheuristic based on tabu search is proposed tosearch the optimal location-price solution of the model.In addition,the authors provide two numericalexamples to illustrate how to obtain the optimal solution and conduct sensitivity analysis.The analysisshows that the best location decision is robust for the follower firm,price game is more intense whenincomes of consumers are lower or there are more substitution products,and neither chain retail gainsfrom the price competition.

Asymmetric Evolution of Two Two-Level Atoms Induced by Position-Dependent Excitation Phase

We report a phenomenon of asymmetric evolution of two two-level atoms which results from pump laser phase based on the model of[Phys.Rev.Lett.101(2008) 153601].Other than investigating the dynamical behavior of whole system,in this paper we investigate the effects of the pump laser phase on dynamic behavior of each atom.We find that two atoms show asymmetry both in time evolution of(population) excitation probability and quantum correlation with environment due to the quantum interference induced by pump laser phase as well as the dipole-dipole interaction.These phenomena are deeply related to the dynamical behavior of the whole system,therefore we can understand the dynamical behavior of whole system caused by pump laser phase from this point of view.