基于变量选择-神经网络模型的复杂路网短时交通流预测

摘要： 针对传统交通流预测模型正在由单断面历史数据处理向多断面、多时刻历史数据处理转变,但在考虑各断面间的影响时,多变的交通状况往往会使预测模型复杂化的问题,引入一种多元线性回归最小绝对收缩和选择算子方法(Lasso),并利用其优秀的变量选择能力,在复杂路网多断面中选出相关性较高的断面；结合神经网络(NN)的非线性特性,提出了Lasso NN组合模型.结果表明：Lasso NN模型在路网交叉口对未来15 min交通流数据预测的误差率低于9.2%；在非交叉口的误差率低于6.7%,总体优于各自单独使用得出的结果.     

基于EPR的供应链治理机制博弈分析

研究了生产者责任延伸(EPR)制度背景下的供应链系统中主体决策影响因素和治理机制的融合问题,基于供应链治理和博弈的理论视角,构造了个体生产者责任(IPR)模式下的非合作博弈模型和集体生产者责任(CPR)模式下的合作博弈模型,分别得出了IPR和CPR模式下企业污染治理技术的最佳决策.研究结果表明,企业的污染治理决策主要取决于企业之间生产技术的差距,以及相互依赖程度.强技术差距和强依赖性更容易导致CPR模式的产生;反之,IPR模式更容易出现在低依赖性和实力相当的企业当中.最后总结了EPR制度下供应链系统动态均衡治理的内部效率机制和外部合法性机制.     

端面顶板冒落高度影响因素 多元线性回归分析

基于数理统计的方法,对影响端面顶板稳定性的多个因素进行了正交试验分析,将顶板冒落高度作为判断指标,得到了各因素的影响程度.影响程度从大到小依次为裂隙发育程度风化岩体强度推进速度端面距=支架初撑力采高.然后,假设端面顶板冒落高度与各影响因素线性相关,采用统计分析软件SPSS对各因素进行多元线性回归分析,结果表明,各因素与顶板冒落高度的线性关系成立,且得到了各因素的回归方程.最后,根据分析结果提出了预防端面顶板冒落的具体措施,为控制端面顶板提供依据.     

初探地理国情普查与省级基础测绘的协同生产

本文主要讲述地理国情普查与基础测绘的主要技术工艺及其协同生产的方式方法。明确基础测绘与地理国情项目的区别与联系,在实际作业中突出重点、避免重复,可以事半功倍。     

Platelet-derived growth factor receptor beta identifies mesenchymal stem cells with enhanced engraftment to tissue injury and pro-angiogenic property

Mesenchymal stem cells (MSCs) are heterogeneous likely consisting of subpopulations with various therapeutic potentials. Here we attempted to acquire a subset of MSCs with enhanced effect in wound healing. We found that human placental MSCs expressing platelet-derived growth factor (PDGF) receptor (PDGFR)-β exhibited greater proliferation rates and generated more colony-forming unit-fibroblast (CFU-F), compared to PDGFR-β^? MSCs. Notably, PDGFR-β⁺ MSCs expressed higher levels of pro-angiogenic factors such as Ang1, Ang2, VEGF, bFGF and PDGF. When 10⁶ GFP-expressing MSCs were topically applied into excisional wounds in mice, PDGFR-β⁺ MSCs actively incorporated into the wound tissue, resulting in enhanced engraftment (3.92 ± 0.31 × 10⁵ remained in wound by 7 days) and accelerated wound closure; meanwhile, PDGFR-β^? MSCs tended to remain on the top of the wound bed with significantly fewer cells (2.46 ± 0.26 × 10⁵) engrafted into the wound, suggesting enhanced chemotactic migration and engraftment of PDGFR-β⁺ MSCs into the wound. Real-Time PCR and immunostain analyses revealed that the expression of PDGF-B was upregulated after wounding; transwell migration assay showed that PDGFR-β⁺ MSCs migrated eightfold more than PDGFR-β^? MSCs toward PDGF-BB. Intriguingly, PDGFR-β⁺ MSC-treated wounds showed significantly enhanced angiogenesis compared to PDGFR-β^? MSC- or vehicle-treated wounds. Thus, our results indicate that PDGFR-β identifies a subset of MSCs with enhanced chemotactic migration to wound injury and effect in promoting angiogenesis and wound healing, implying a greater therapeutic potential for certain diseases.     

Improved hemimorphite flotation using xanthate as a collector with S(Ⅱ) and Pb(Ⅱ) activation

The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.     

Variable Selection via Generalized SELO-Penalized Cox Regression Models

The seamless-L_0(SELO) penalty is a smooth function that very closely resembles the L_0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection. In this paper, the authors first generalize the SELO penalty to a class of penalties retaining good features of SELO, and then develop variable selection and parameter estimation in Cox models using the proposed generalized SELO(GSELO) penalized log partial likelihood(PPL) approach. The authors show that the GSELO-PPL procedure possesses the oracle property with a diverging number of predictors under certain mild, interpretable regularity conditions. The entire path of GSELO-PPL estimates can be efficiently computed through a smoothing quasi-Newton(SQN) with continuation algorithm. The authors propose a consistent modified BIC(MBIC) tuning parameter selector for GSELO-PPL, and show that under some regularity conditions, the GSELOPPL-MBIC procedure consistently identifies the true model. Simulation studies and real data analysis are conducted to evaluate the finite sample performance of the proposed method.     

A Layer-Stripping Method for 3D Near-Surface Velocity Model Building Using Seismic First-Arrival Times

In order to improve the efficiency of 3D near-surface velocity model building, we develop a layer-stripping method using seismic first-arrival times. The velocity model within a Common Mid-Point (CMP) ...     

人工智能心理学研究的知识图谱分析

借助CitespaceⅢ对选自WoS的人工智能心理学研究文献进行知识图谱探析,结合自动聚类视图与议题标签展现了人工智能心理学领域的6个知识聚类:#0人工智能解决问题议题;#1人工与人类认知共性议题;#2人工智能学习议题;#3人工智能脑科学议题;#4人工智能环境认知议题;#5人工智能表征议题。在深入探究各聚类的核心与热点知识的基础上分析了人工智能心理学发展的各阶段特征:1.上世纪50年代图灵和米勒等人对机器认知与学习等概念的猜想与初探;2.70-90年代纽厄尔、西蒙和莱尔德等人基于模块记忆与层级分析对人工智能信息处理模型的系统性构建;3.本世纪初基于神经生理学的降维数据认知理论的发展;4.当下人工智能贝叶斯大脑与深度学习理论的兴起。