关注社交异配性的社交机器人检测框架

随着社交机器人的迭代,其倾向于与正常用户进行更多交互,对其检测变得更具挑战性。现有检测方法大多基于同配性假设,由于忽视了不同类用户间存在的联系,难以保持良好的检测性能。针对这一问题文章提出一种关注社交异配性的社交机器人检测框架,以社交网络用户间的联系为依据,通过充分挖掘用户社交信息来应对异配影响,并实现更精准的检测。文章分别在同配视角和异配视角下看待用户之间的联系,将社交网络构建为图,通过消息传递机制实现同配边和异配边聚合,以提取节点的频率特征,同时利用图中各节点特征聚合得到社交环境特征,将以上特征混合后用于检测。实验结果表明,文章所提方法在开源数据集上的检测效果优于基线方法,证明了该方法的有效性。

伯努利生成矩阵码中的统计力学性质

从统计物理的角度,结合自旋玻璃理论与复杂网络理论,系统地研究了伯努利系统低密度生成矩阵码的统计力学性质.首先给出系统低密度生成矩阵码的伯努利构造、编译码框架,并讨论节点度分布以及正规图与Erdös-Rényi(ER)随机图的联系.然后研究自旋玻璃理论框架下的编译码模型、码本与微观构型的关系、空腔方法与消息传递方程,提出针对系统码的种群动力学算法来高效分析其渐近性能.最后提出正规图配置模型(Normal Graph Configuration Model,NGCM)生成具有连接偏好性的正规图,研究异配性对置信传播(Belief Propagation,BP)译码算法性能的影响,并进一步分析其机理.仿真结果表明,种群动力学算法与BP译码算法本质上相同,但前者不局限于某个具体的码,因此在分析码集的渐近性能时更具优势.此外,适当的异配性能够显著提升BP算法在瀑布区的译码性能,获得更低误码率(Bit Error Rate,BER)并且降低译码迭代次数(复杂度).

子网络的连接模式对关联网络可靠性影响研究

为了分析关联网络中子网络之间连接方式对网络可靠性的影响,根据不同子网络之间连接的度相关性,建立关联网络中子网络之间的连接模型,以节点之间非交叉路径的最大条数为可靠性测度,对由4个子网络组成的网络系统进行了分析。结果表明,当子网络之间的连接具有异配性时,网络具有较高的可靠性,但过大的异配性反而会降低网络的可靠性。

增长网络结点度相关性的混合系数

鉴于增长网络的一个显著特征是相邻结点之间的关系自发地形成,与被广泛研究的结点度分布相比,此种相邻结点关系的研究能更清楚地揭示更多内在的增长网络的结构特征.为此提出了一种称为混合系数M(g)的网络结点度相关性测度用来判别增长网络的同配和异配性.通过大量的计算机模拟和数值统计,分析了该测度关于网络规模N和稠密度ρ的稳定性,结果显示该测度比判别网络同配和异配性的Newman相关系数r(g)更具有稳定性.因此,混合系数M(g)具有优越性,可更好地被应用到实际网络的同配和异配性分析中.

集群知识网络结构特征对集群弹性的影响研究——基于双元性创新的视角

本文从双元性创新的视角研究了集群知识网络的结构特征对集群弹性的影响。在网络视角下,集群是由本地化知识网络构成的关系结构。这一关系结构的结构特征可以通过度分布和度相关性统计指标来衡量。根据集群知识网络的层级与匹配性,集群知识网络呈现出三种典型的结构,它们分别是随机网络、同配性核心/外围网络、异配性核心/外围网络。研究表明,集群中知识网络的同配性特征会弱化集群对新观念吸收与应用的整合能力,这可能是区域负向锁定的根源。而具备异配性特征的网络能够对挖掘性创新的知识和探索性创新的知识进行整合,有利于双元性创新,因而能够加强集群的弹性能力。

复杂网络理论在Internet拓扑特性分析中的应用

利用复杂网络理论对Internet进行研究,探索Internet复杂系统的现象,揭示这些现象背后的起源、不变特性以及动态规律,已成为计算机科学领域所关心的重要问题之一。介绍了复杂网络的研究简史,研究的主要内容、方法与工具,以及复杂网络的基本概念和特征量,并对目前在Internet拓扑特性分析研究方面的研究成果及经验结果进行了归纳总结,同时给出了复杂网络理论在Internet研究中的发展方向。

航空企业视角的中国航空客运网络组织模式

基于37个中国航空企业的航班大数据,选取对外联系度、异(同)配性系数、层次分析、优势生态位分析等方法对中国航空客运网络组织模式进行分析。研究发现:①中国航空网络发育整体趋于成熟,已形成明显的层次性和核心-边缘结构,航空企业的航空网络均蕴藏位序-规模规律,依据其机场节点、航线和航班数量可划分为6个层级;②依据企业视角与网络规模、层次性与同配性/异配性等指标的综合度量,中国航空企业的网络组织模式可划分为核心培育阶段、核心竞争阶段、过渡阶段与稳定增长阶段4种类型;③航空企业的航空网络包括核心-边缘同配性网络和核心-边缘异配性网络,企业间竞争焦点主要表现为"核心"的竞争;④结合航空客运网络组织模式的判定,当前中国航空网络存在两条收敛规律:层次性收敛与同配性/异配性收敛;⑤实力强、规模大的航空企业在全国通航城市的比例分布均匀,具有较高生态位;实力弱、规模小的航空企业在全国通航城市的分布具有区域性且比例不均,生态位较低。为优化航空网络结构、避免企业恶性竞争,中国不同等级的航空企业一方面需结合自身发展阶段不断优化网络组织模式,寻求与企业等级相适应的生态优势位;另一方面要加强合作,避免航线饱和问题,提高整个航空网络的韧性和运营效率。

Microscopic phase-field study on directional coarsening mechanism caused by interaction between precipitates in Ni-Al-V alloy

A microscopic phase-field model was used to investigate a directional coarsening mechanism caused by the anisotropic growth of long period stacking and different effects of phases on precipitation in Ni-Al-V alloy.The results show that DO22 mainly coarsens along its short axis,which may press the neighboring L12,leading to the interaction among atoms.Diffusion channels of Al are formed in the direction where the mismatch between γ＇ and γ reduces;the occupation probabilities are anisotropic in space;and direction coarsening of L12 occurs finally.With a rise of ageing temperature,phases appear later and DO22 is much later at a higher temperature,the average occupation probabilities of Al and V reduce,and Al changes more than V.

Development of HBsAg-Binding Aptamers that bind HepG2.2.15 cells via HBV surface antigen

Hepatitis B virus surface antigen （HBsAg）, a specific antigen on the membrane of Hepatitis B virus （HBV）-infected cells, provides a perfect target for therapeutic drugs. The development of reagents with high affinity and specificity to the HBsAg is of great significance to the early-stage diagnosis and treatment of HBV infection. Herein, we report the selection of RNA aptamers that can specifically bind to HBsAg protein and HBsAg-positive hepatocytes. One high affinity aptamer, HBs-A22, was isolated from an initial 115 met library of -1.1 ×10^15 random-sequence RNA molecules using the SELEX procedure. The selected aptamer HBs-A22 bound specifically to hepatoma cell line HepG2.2.15 that expresses HBsAg but did not bind to HBsAg-devoid HepG2 cells. This is the first reported RNA aptamer which could bind to a HBV specific antigen. This newly isolated aptamer could be modified to deliver imaging, diagnostic, and therapeutic agents targeted at HBV-infected cells.

Fluorescent vital staining of plant sexual cell nuclei with DNA-specific fluorochromes and its application in gametoplast fusion

DNA-binding fluorochromes are often used for vital staining of plant cell nuclei. However, it is not always sure whether the cells after staining still remain in living state. We chose several criteria to estimate the validity of real vital staining for sexual cell nuclei. These were: the cytoplasmic streaming in pollen tubes whose nuclei were stained, the simultaneous visualization of fluo-rochromatic reaction and nucleus staining in isolated generative cells, and the capability of isolated, prestained generative or sperm cells to fuse with other protoplasts. The results confirmed that 4',6-diamidino-2-phenylindole (DAPI), Hoechst 33258 and mithramycin could be used as real vital stains, though their efficiency varied from case to case; among them DAPI showed best effect. The fluorescent vital staining technique offered a useful means fori-dentification and selection of heterokaryons in gametoplast manipulation studies.

Is extended biopsy protocol justified in all patients with PSA≥20ng/mL?

The aim of this study was to investigate whether it was necessary to increase the number of cores at initial prostate biopsy with patients of prostate-specific antigen （PSA） ≥ 20 ng/mL and to explore an appropriate individualized transrectal ultrasonograhpy （TRUS）-guided prostate biopsy for the detection of prostate cancer in men suspicious of prostate cancer. Methods： A total of 115 patients with PSA ≥ 20 ng/mL and suspicious of prostate cancer were prospectively randomized to perform TRUS-guided biopsy. Patients were randomized to a ＂6 ＋ X＂ cores or a ＂10 ＋ X＂ cores protocol. The primary end point was cancer detection rate. Secondary end points were cancer characteristics, rate of complications and the level of pain experienced by patients during TRUS-guided prostate biopsy. Results： Preoperative variables were similar in both groups. The overall prostate cancer detection rate was 73.9%. The ＂10 ＋ X＂ cores strategy increased cancer detection rate only 9.7% in patients with PSA ≥ 20 ng/mL but 〈 50 ng/mL, while there was no difference between the two strategies for cancer detection in patients with PSA ≥ 50.1 ng/mL. The number of extended biopsy cores and pain score of extended biopsy in prostate cancer patients increased significantly （P 〈 0.001）. Conclusion： Our findings suggest that there is no significant advantage in using extended biopsy protocol in all patients with PSA≥20 ng/mL.

Non-Rigid Object Tracking by Anisotropic Kernel Mean Shift

Mean shift,an iterative procedure that shifts each data point to the average of data points in its neighborhood,has been applied to object tracker.However,the traditional mean shift tracker by isotropic kernel often loses the object with the changing object structure in video sequences,especially when the object structure varies fast.This paper proposes a non-rigid object tracker by anisotropic kernel mean shift in which the shape,scale,and orientation of the kernels adapt to the changing object structure.The experimental results show that the new tracker is self-adaptive and approximately twice faster than the traditional tracker,which ensures the robustness and real time of tracking.

城市群交通网络特性

城市群经济社会蓬勃发展要求有相适应的交通运输网络为其提供强有力的支持,因此,以长株潭城市群交通网络为背景,研究了交通网络特性。给出了道路的n阶平均度、网络平均n-聚集系数、网络失效弹性等概念,定义了度为k的道路的介数中心性和基于节点介数中心性的结构熵,在数值计算的基础上分析了交通网络性质。研究分析发现:(1)五个交通网络中,整个长株潭交通网络是比较抗失效的,湘潭交通网络显示出对失效的脆弱性,而长沙市及长株潭整个交通网络是最为有序的;(2)长株潭城市群交通网络是小世界网络而不具有无标度性;(3)对网络匹配关系研究表明交通网络是异配的,利用网络异配性初步探讨了网络层阶性。

CHANGES OF SOLUBLE FAS AND SOLUBLE FAS LIGANDIN SERUM AND PERITONEAL FLUID OF INFERTILEPATIENTS WITH ENDOMETRIOSIS

Objective To evaluate the relationship between levels of soluble Fas(sFas)and soluble Fas ligand(sFasL)in serum and peritoneal fluid of endometriosis-associated infertility. Methods The soluble Fas ligand and soluble Fas levels in serum and peritoneal fluid of 20 infertile patients with endometriosis were assessed with enzyme-linked immunosorbent assay, and were compared with 14 infertile patients due to chronic pelvic infectious disease and 16 fertile controls. Results The sFasL levels were significantly higher in infertile patients with endometriosis(175.09 ± 80.55 pg/mL in serum and 284.50 ± 152.38 pg/mL in peritoneal fluid)than those of infertile controls (88.47 ± 43.55 pg/mL in serum and 17.30 ± 9.62 pg/mL in peritoneal fluid)and fertile controls(16.13 ± 11.75 pg/mL in serum and 8.84 ± 2.31 pg/mL in peritoneal fluid). In contrast, as for the sFas levels, infertile patients with endometriosis(828.60 ± 429.65 pg/mL in serum and 349.61 ± 288.89 pg/mL in peritoneal fluid)did not show any significant difference compared with those in infertile patients resulting from pelvic infectious disease(868.75 ± 570.48 pg/mL in serum and 181.76 ± 157.78 pg/mL in peritoneal fluid)and fertile control(822.26 ± 129.12 pg/mL in serum and 318.42 ± 145.16 pg/mL in peritoneal fluid). Conclusions Based upon these results, high level of sFasL in serum and peritoneal fluid and thus apoptosis mediated by it may be implicated in the mechanism involved in endometriosis-related infertility.

IDENTIFICATION OF SPECIFIC PEPTIDE LIGANDS FOR B-LYMPHOMA CELL AND ITS EFFECT ON TYROSINE PHOSPHORYLATION AND CELL APOPTOSIS

Objective To search novel method for diagnosis and therapy of B-lymphoma, specific small mo-lecular peptide ligands against binding site of tumor cells were screened and its effects on signal transduction and cell apoptosis were tested. Methods Specific peptide ligands were screened by binding with site of human B lymphoma cell(OC1LY8)using peptide-bead libraries. The identified peptides were characterized with responsible cellsby rebinding test. The role of tyrosine phosphorylation of peptide ligand was tested by Western blot; and its apoptosispromoting role was observed by confocal fluorescent microscope. Results Specific peptide ligand was able to bind specifically to site on cell surface and enter into cytoplasm. Tetrameric peptide ligand was able to strongly trigger signal transduction resulting in tyrosine phosphorylation and cellular apoptosis in OC1LY8 cell line. Conclusion Screened peptide ligand can effectively bind with OC1LY8 cell, stimulate cellular tyro-sine phosphorylation and induce cellular apoptosis.

基于谱分析的无线传感器网络模块度分簇算法

基于谱分析与模块度,提出一种无线传感器网络分簇算法(CHSM),首先利用非平凡特征向量获得传感器网络的原始簇结构;然后借助模块度的增量来评估、合并原始簇,从而形成一个与真实网络相匹配的簇结构;同时设计了一种能量异配度函数,并利用各节点的能量异配度及其剩余能量在各个簇内选取簇头节点,仿真结果表明,CHSM算法找到的簇结构具有更高的模块度,其选取的簇头节点具有更高的能量异配度,进而表明了所提出的算法能有效延长网络的寿命。

Endocrine correlates of mate choice and promiscuity in females of a socially monogamous avian mating system with alternative male reproductive phenotypes

While our understanding of male reproductive strategies is informed by extensive investigations into endocrine mechanisms, the proximate mechanisms by which females compete for mates and adjust reproduction to social environment remains enigmatic. We set out to uncover endocrine correlates of mate choice, social environment, and reproductive investment in female red-backed fairy-wrens Malurus melanocephalus. In this socially monogamous, yet highly sexually promiscuous species, females experience discrete variation in the phenotype of their mates, which vary in both plumage signals and level of paternal care, and in the composition of their breeding groups, which consist of either the pair alone or with an additional cooperative auxiliary; fe- male investment varies according to these social parameters. We found that androgen, estrogen, and glucorticoid levels varied with reproductive stage, with highest androgen and estrogen concentrations during nest construction and highest corticosterone concentrations during the pre-breeding stage. These stage-dependent patterns did not vary with male phenotype or auxiliary presence, though androgen levels during pre-breeding mate selection were lower in females obtaining red/black mates than those obtaining brown mates. We found no evidence that androgen, estrogen, or corticosterone levels during the fertile period were re- lated to extra-pair young （EPY） frequency. This study demonstrates clear changes in steroid levels with reproductive stage, though it found little support for variation with social environment. We suggest hormonal responsiveness to social factors may be physiologically constrained in ways that are bypassed through exogenous hormone manipulations.

Perpendicular magnetic clusters with configurable domain structures via dipole-dipole interactions

Magnetic single-domain islands based on in-plane anisotropy （usually, shape anisotropy） and their dipole-dipole interactions have been investigated extensively in recent years. This has been driven by potential applications in magnetic recording, spintronics, magneto-biology, etc. Here, we propose a concept of out- of-plane magnetic dusters with configurable domain structures （multi-flux states） via dipole-dipole interactions. Their flux stages can be switched through an external magnetic field. The concept has been successfully demonstrated by patterned [Co/Pd] islands. A [Co/Pd] multilayer exhibits a large perpendicular anisotropy, a strong physical separation, and uniform intrinsic properties after being patterned into individual islands by electron beam lithography. A three- island cluster with six stable flux states has been realized by optimizing island size, thickness, gap, anisotropy, saturation magnetization, etc. Using [Co/Pd] multilayers, we have optimized the island structure by tuning magnetic properties （saturation magnetization and perpendicular anisotropy） using Landau-Liftshitz- Gilbert （LLG） simulation/calculation. Potential applications have been proposed, including a flexi-programmable logic device with AND, OR, NAND, and NOR functionalities and a magnetic domino, which can propagate magnetic current as far as 1 μm down from the surface via vertical dipole-dipole interactions.

Effects of nitrogen addition on clonal integration between mother and daughter ramets of Moso bamboo: a ^(13)C-CO_(2) pulse labeling study

Resource sharing among connected ramets(i.e.clonal integration)is one of the distinct traits of clonal plants.Clonal integration confers Moso bamboo(Phyllostachys pubescens)a strong adaptability to different environmental conditions.But the mechanisms of how clonal integration makes Moso bamboo has better performance are still poorly understood.In this study,acropetal and basipetal translocation of photosynthates between Moso bamboo ramets were analyzed separately to investigate how clonal fragments obtain higher benefits under heterogeneous N conditions.Clonal fragments of Moso bamboo consisting of two interconnected mother–daughter ramets were used,each of the ramets was subjected to either with or without N addition.The acropetal and basipetal translocation of ^(13)C-photosynthates was separated via single-ramet ^(13)C-CO_(2)-labeling.Mother ramets translocated more ^(13)C-photosynthates to daughter ramets with N addition,and the translocation of ^(13)C-photosynthates to mother ramets was more pronounced when daughter ramets were treated with N addition.The ^(13)C-photosynthates that were translocated from mother ramets without and with N addition were mainly invested in the leaves and roots of daughter ramets with N addition,from daughter ramets with N addition were mainly invested in the leaves and roots of mother ramets with and without N addition,respectively.These results suggest that mother ramets preferentially invest more resources in nutrient-rich daughter ramets,and that daughter ramets serve as efficient resource acquisition sites to specialize in acquiring abundant resources based on the resource conditions of mother ramets.Clonal plants can improve their resource acquisition efficiency and maximize the overall performance in this way.

Variation in sexual dimorphism and assortative mating do not predict genetic divergence in the sexually dimorphic Goodeid fish Girardinichthys multiradiatus

Sexual dimorphism is often used as a proxy for the intensity of sexual selection in comparative studies of sexual selection and diversification. The Mexican Goodeinae are a group of livebearing freshwater fishes with large variation between species in sexual dimorphism in body shape. Previously we found an association between variation in morphological sexual dimorphism between species and the amount of gene flow within populations in the Goodeinae. Here we have examined if mor- phological differentiation within a single dimorphic species is related to assortative mating or gene flow between populations. In the Amarillo fish Girardinichthys multiradiatus studies have shown that exaggerated male fins are targets of female preferences. We find that populations of the species differ in the level of sexual dimorphism displayed due to faster evolution of differences in male than female morphology. However, this does not predict variation in assortative mating tests in the laboratory; in fact dif- ferences in male morphology are negatively correlated with assortative mating. Microsatellite markers reveal significant genetic differences between populations. However, gene flow is not predicted by either morphological differences or assortative mating. Rather, it demonstrates a pattern of isolation by distance with greater differentiation between watersheds. We discuss the caveats of predicting behavioural and genetic divergence from so-called proxies of sexual selection [Current Zoology 58 （3）： 440-452, 2012].