Using Cross Entropy as a Performance Metric for Quantifying Uncertainty in DNN Image Classifiers: An Application to Classification of Lung Cancer on CT Images

Cross entropy is a measure in machine learning and deep learning that assesses the difference between predicted and actual probability distributions. In this study, we propose cross entropy as a performance evaluation metric for image classifier models and apply it to the CT image classification of lung cancer. A convolutional neural network is employed as the deep neural network (DNN) image classifier, with the residual network (ResNet) 50 chosen as the DNN archi-tecture. The image data used comprise a lung CT image set. Two classification models are built from datasets with varying amounts of data, and lung cancer is categorized into four classes using 10-fold cross-validation. Furthermore, we employ t-distributed stochastic neighbor embedding to visually explain the data distribution after classification. Experimental results demonstrate that cross en-tropy is a highly useful metric for evaluating the reliability of image classifier models. It is noted that for a more comprehensive evaluation of model perfor-mance, combining with other evaluation metrics is considered essential. .

Effect of landform on aerodynamic performance of high-speed trains in cutting under cross wind

The effects of the different landforms of the cutting leeward on the aerodynamic performance of high-speed trains were analyzed based on the three-dimensional, steady, and incompressible Navier-Stokes equation and k-e double-equation turbulent model. Results show that aerodynamic forces increase with the cutting leeward slope decreasing. The maximum adding value of lateral force, lift force, and overturning moment are 147%, 44.3%, and 107%, respectively, when the slope varies from 0.67 to -0.67, and the changes in the cutting leeward landform have more effects on the aerodynamic performance when the train is running in the line No. 2 than in the line No. 1. The aerodynamic forces, except the resistance force, sharply increase with the slope depth decreasing. By comparing the circumstance of the cutting depth H=-8 m with that of H=8 m, the resistance force, lateral force, lift force, and overturning moment increase by 26.0%, 251%, 67.3% and 177%, respectively. With the wind angle increasing, the resistance force is nonmonotonic, whereas other forces continuously rise. Under three special landforms, the changes in the law of aerodynamic forces with the wind angle are almost similar to one another.

Growth Performance of Different Cross Combinations of Quality Lean Type Pig

Ten healthy weaning piglets of Landrace x Yorkshire （LY） in good body condition with body weight of （24 ± 1.27） kg were selected, and ten weaning piglets of Berkshire × LY （BLY） and Duroc × LY （DLY） with similar situation were also selected respectively to study the growth performance of different cross combinations. Three groups of experimental pigs were bred with conventional diet. The results showed that the average dry matter intakes of combinations of BLY and DLY were slightly decreased by 4.97% and 5.47% compared with the combination of LY, while average daily gain was significantly increased by 3.13% and 1.14%, and feed-weight ratio was decreased by 7.94% and 6.35%, respectively; economic benefit per pig was increased by 0.61 and 0.41 yuan, respectively. The combinations of BLY and DLY have better growth performance, which can be promoted in the production.

A NOVEL CROSS-LAYER STRATEGY OF VIDEO TRANSMISSION TO SOLVE PERFORMANCE ANOMALY IN MULTI-RATE IEEE 802.11 NETWORKS

When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it is bad for video service transmission. Considering that video is very sensitive to packet delivery delay but can tolerate some packet losses, we propose a novel cross-layer scheme which takes these two characteristics into consideration. Firstly, the maximum number of retransmissions for a video Medium Access Control (MAC) frame is computed in MAC layer according to video frame rate requirement of application layer and current access delay of MAC layer. Secondly, within the margin of the tolerant Packet Loss Rate (PLR) of application layer, several video MAC frames are allowed to drop so that we can adaptively select the transmission rate as high as possible for the rest of video MAC frames in terms of current channel quality and the maximum number of retransmissions. Experiment results show that the proposed method can reduce the delay and jitter of video service and improve the throughputs of fast hosts. Therefore, it increases the quality of reconstructed video to a certain extent and relieves the performance anomaly of network effectively.

Assessing performance of cross-administrative environment governance based on PSR model:An empirical analysis of the Beijing-Tianjin-Hebei region

As an effective environment governance tool,environment governance performance evaluation is an important content and method to promote the modernization of environment governance system and governance ability.The environmental pollution of the Beijing-Tianjin-Hebei region has typical cross-administrative characteristics.Based on the analysis of the major environmental pollution problems in the Beijing-Tianjin-Hebei region,according to the international environment governance PSR model,a performance evaluation system that applies to the environment governance of Beijing-Tianjin-Hebei region is established.Meanwhile,the principal component analysis method is applied to conduct an empirical analysis of the environmental governance panel data for the 13 major cities in the Beijing-Tianjin-Hebei region from 2014 to 2016.The results show that most of the cities in the Beijing-Tianjin-Hebei region attach great importance to reduction of emission and pollutants,continuously alleviating the stress of environmental governance.However,the overall improvement of the environment governance performance in Beijing-Tianjin-Hebei region has presented a polarization imbalance.There is a clear tendency for subjective biases in the implementation of environment governance and a lack of comprehensive and systematic governance.According to the environment governance performance evaluation result of Beijing-Tianjin-Hebei region,the cross-administrative regional environment governance should improve the environment governance performance evaluation system as soon as possible,strengthen the consistency of the environment governance objectives,and implement comprehensive and systematic governance for the regional environment.

Preparation and Performance of Geopolymers

The influence of each factor on the reaction of geopolymers material was investigated by using the orthogonal experimental design method, which got the optimal condition of reaction. Based on this results the performances of geopolymers were investigated. The results are as follows： （1） The effect of each factor on the compressive strength of geopolymers was different; （2） For paste the optimal condition of reaction is that the modulus and the concentration of sodium silicate solution are 1.2 and 40%, the calcined temperature and calcined time of kaolin are 800 ℃ and 2 h, and the liquid-solid ratio is 1.25; （3） When the pH value of solution is higher than l, the compressive strength of Geopolymers will not decrease as that in the water; （4） As the calcined temperature of samples were lower than 700 ℃ the heat-resistant of geopolymers was good;（5） Geopolymers is unlikely to react with the active aggregate.

A Robust Method for Ordering Performances of Multi-assets, Based Purely on Their Return Series

This study propose a new robust method to rank the performances of multi-assets （portfolios）, based purely on their return time series. This method makes no assumption on the distributions. Topsoe distance is symmetrized Kullback-Leibler divergence by average of the probabilities. The square root of Topsoe distance is a metric. We extend this metric from probability density functions to real number series on （0, 1 ]. We call it ST-metric. We show the consistency of ST-metric with mean-variance theory and stochastic dominance method of order one and two. We demonstrate the advantages of ST-metric over mean-variance rule and stochastic dominance method of order one and two.

连锁股东会影响企业ESG表现吗?

ESG作为企业实现绿色转型的重要手段,引起了广泛关注。连锁股东作为市场重要参与者,对企业ESG表现会产生何种影响值得进一步探究。基于2011—2022年中国沪深A股上市公司数据,检验了连锁股东对企业ESG表现的影响。研究发现:第一,连锁股东对企业ESG表现具有促进作用,这一结论在经历内生性与稳健性检验后依然成立;第二,机制分析发现,连锁股东通过提高分析师关注水平及内部控制质量进而促进企业ESG表现提升,即连锁股东对企业ESG表现具有信息效应及治理效应;第三,企业数字化转型在连锁股东与企业ESG表现之间起到正向调节作用,其强化了连锁股东对企业ESG表现的积极作用;第四,异质性分析发现,在非国有企业、媒体关注较高的企业与非重污染企业中,连锁股东对促进企业ESG表现提升的作用更显著。研究结论拓展了连锁股东经济后果的研究,也为企业提升ESG表现提供了参考。

高温预处理对杨木正交胶合木剪力墙抗侧力性能的影响

[目的]研究往复荷载作用时国产速生杨木正交胶合木(CLT)剪力墙的抗侧力性能,阐明木材高温预处理和加速老化对剪力墙抗侧力性能的影响,为高温改性技术和国产速生木材在建筑结构中的高效利用提供参考。[方法]以木结构建筑常用的进口欧洲云杉规格材为对照,以相同强度等级的国产速生杨木为研究对象,选用180℃为预处理温度对杨木进行高温改性,制备5面全尺寸正交胶合木剪力墙,开展往复荷载作用时加速老化前后正交胶合木剪力墙的抗侧力性能试验。[结果]与相同层板强度等级的欧洲云杉正交胶合木剪力墙相比,往复荷载作用时未处理杨木正交胶合木剪力墙的极限承载力、弹性抗侧刚度、耗能能力分别降低5.8%、12.9%、8.0%;木材经高温预处理、墙体经加速老化或二者联合处理后,杨木正交胶合木剪力墙的抗侧力性能指标不同程度降低;与未处理杨木正交胶合木墙体相比,加速老化处理后,墙体的极限承载力、弹性抗侧刚度、耗能能力分别降低9.4%、9.7%、11.2%;木材经高温预处理后,经加速老化,墙体的极限承载力、弹性抗侧刚度、耗能能力变化较小,分别降低2.9%、2.4%、5.0%。[结论]往复荷载作用时,国产速生杨木正交胶合木剪力墙的抗侧力性能略低于相同层板强度等级的欧洲云杉正交胶合木剪力墙,水平力作用时二者具有相似破坏模式,均为抗拔连接件节点处钉子被剪断;木材经高温预处理、墙体经加速老化或二者联合处理后,杨木正交胶合木剪力墙的破坏模式均为底部墙角抗拔连接件处木材被拉断或劈裂破坏;木材高温预处理能够有效降低加速老化对剪力墙抗侧力性能的影响,具有相对较好的抗老化能力;建立正交胶合木剪力墙极限承载力计算模型,理论值与试验值误差小于10%。

价值网络视角下跨界整合对企业创新绩效的影响——组织柔性的中介效应

在数字经济背景下,跨界创新成为企业新的创新范式。跨界整合对于企业顺利实施跨界创新战略极为关键。现有研究关注跨界整合产生的影响,但对于企业如何在跨界整合过程中通过调整组织结构与惯例影响创新绩效的机制探讨不足。基于价值网络视角,以358家企业为研究对象,采用层次回归分析方法检验跨界整合对企业创新绩效的影响机制以及组织柔性的中介作用。研究发现:①跨界资源价值识取与跨界资源价值配用作为跨界整合的两个维度对企业创新绩效具有显著正向影响;②组织结构柔性和惯例更新在跨界整合与创新绩效之间发挥显著中介作用。厘清跨界整合不同维度对创新绩效的作用,验证“跨界整合—组织柔性—创新绩效”影响路径,可深化既有理论对跨界整合作用的认知,对于企业跨界创新战略实施具有重要指导意义。

基于主成分分析的二元杂交鸽生长性能和繁殖性能评价

为评价石歧鸽、白卡奴鸽、欧洲肉鸽三个品种鸽不同二元杂交组合的生长性能和繁殖性能,寻求最佳二元杂交组合,试验设置XL组合[石歧鸽(X)■×欧洲肉鸽(L)♀]、XY组合[石歧鸽(X)■×白卡奴鸽(Y)♀]、LY组合[欧洲肉鸽(L)■×白卡奴鸽(Y)♀]和LX组合[欧洲肉鸽(L)■×石歧鸽(X)♀],每个组合170对,进行为期1年的生长性能和繁殖性能统计,比较产蛋间隔、产蛋窝次、年产蛋数、无精蛋数、死胚数、出雏数、出栏乳鸽数、死雏数、受精率、出雏率、成活率、公鸽重、母鸽重、28日龄乳鸽体重等指标,运用主成分分析方法进行杂交组合的综合评价和优良组合的筛选。结果表明:XY组合的产蛋间隔最短(25.50 d),极显著低于LY组合(31.28 d)和LX组合(30.67 d,P<0.01);XY组合的年产蛋数最多(22.69个),极显著高于LY组合(21.28个,P<0.01);LY组合受精率最高为88.96%,极显著高于XY组合(83.51%,P<0.01),显著高于XL组合(84.57%,P<0.05);XY组合出栏乳鸽数最多,为13.57只。产蛋窝次、产蛋数、无精蛋数和死胚数与产蛋间隔之间呈强负相关,产蛋数、无精蛋数、死胚数与产蛋窝次之间呈强正相关,乳鸽重与公鸽重和母鸽重之间呈强正相关,XL组合的公母鸽体重均较重,因此该组合的乳鸽体重最重(547.65 g)。LX组合死淘率低,出栏数相对较多,且28日龄乳鸽体重较重。从繁殖性能中提取了三个主成分,分别为产蛋因子、乳鸽数因子、乳鸽体重因子,LX组合产蛋因子得分较高,LX组合乳鸽数因子较高。说明LX组合适合于肉鸽生产;XY组合产蛋量高,适合于蛋用鸽生产。

用于跨介质航行器的后掠机构分析

主要阐述跨介质航行器后掠结构的设计和分析。对航行器介质转换的平滑过渡,包括机翼的收放机制、结构设计、静力学和动力学分析等多个方面进行重点研究。利用有限元分析和模态分析,展示了机翼结构在受到载荷时的响应,分析了机翼在折叠展开过程中对机构整体的气动影响。此外,通过力矩仿真进一步验证后掠机构设计的合理性和实用性,有效减弱50%入水冲击,水下航行速度提升2.5倍,过渡时间缩短1.8 s。研究成果揭示了后掠机构在改善航行器介质转换性能方面的有效性,为跨介质航行器的设计和性能优化提供了新方法。

跨界团队网络特征对其颠覆性创新绩效的影响研究

跨界团队在企业等创新主体开展颠覆性创新活动中发挥重要作用,而运用机器学习方法识别其网络特征与颠覆性创新绩效之间殊途同归的组态路径是一个亟待解决的重要问题。本文基于Incopat专利检索平台无人机领域139999条专利数据,采用社区发现算法在专利发明人合作关系数据中识别185个跨界团队,依据社会网络理论遴选跨界团队网络特征变量,利用k-means聚类算法对跨界团队进行类型划分,并运用决策树CART(classification and regression trees)算法挖掘不同类型跨界团队网络特征对其颠覆性创新绩效的影响。研究结果表明,①跨界团队共有二元合作、类完全合作和复杂合作3种合作类型,不同跨界团队类型对颠覆性创新绩效影响具有差异性,即类完全合作团队高颠覆性创新绩效占比最高,二元合作团队高颠覆性创新绩效占比最低;②合作强度具有普适性,它是影响不同跨界团队形成不同水平颠覆性创新绩效的核心因素;③合作强度正向影响二元合作团队颠覆性创新绩效,类完全合作团队的颠覆性创新绩效受聚集系数、合作强度与团队规模的共同影响,而对于合作强度较高的复杂合作团队而言,保持较低的网络密度有利于其提升颠覆性创新绩效。

轻质高绝缘复合芯体制备及其在66 kV复合横担中的应用

随着“双碳”战略的逐步落实,新型复合材料横担正逐步代替铁制横担,在电力线路中的应用日益广泛。文中制备得到密度为1.1 g/cm^(3)的66 kV轻质高绝缘复合绝缘横担,并对其进行吸水率、染料渗透、水扩散泄漏电流、击穿强度、热诱导、机械及电气试验。试验结果表明:填充芯体材料样品的质量吸水率为0.141%,水扩散泄漏电流小于103.3μA,交流击穿强度大于71 kV/cm,各项性能指标均达到DL/T 1580—2016棒形复合绝缘子用芯棒技术规范对于理化性能、电气性能及机械性能的标准要求,样品及横担整体无明显缺陷,横担耐老化性较好。同时,轻质高绝缘复合绝缘横担微观界面结合良好,绝缘性能优于传统实心横担,满足新型电力系统清洁低碳、安全可靠的应用需求。

收放伞绳对十字型伞静态气动特性影响的数值模拟研究

为研究十字型降落伞作为主动控制装置时,其可控性与气动特性的规律,建立了不同伞绳收缩比δ为0、10.0%、12.5%、15.0%、20.0%、25.0%时十字型伞无限质量充气的有限元模型,基于任意拉格朗日-欧拉方法进行数值模拟,分析了十字型降落伞收缩伞绳,引起伞面几何构型不对称对气动特性的影响.结果表明:不同攻角为0°、5°、10°时,十字型降落伞的平均阻力系数随伞绳收缩比δ的增大而减小;十字型伞的瞬时升力峰值随着伞绳收缩比δ的增加而增大,方向始终由伞绳收缩一侧指向另一侧,具有较强的时变特性.

ESG表现与企业跨区域投资

跨区域投资不仅是企业实现规模扩张的重要方式,也是政府促进区域协调发展的重要抓手。文章选取2009—2022年我国A股上市公司数据,探讨企业ESG表现与跨区域投资的关系。研究发现:良好的ESG表现会促进企业跨区域投资;机制检验发现,企业ESG表现主要通过资源获取效应和市场拓展效应促进跨区域投资,当企业信息披露质量越高、受到的融资约束越强、所在地区的市场化水平越低时,ESG表现对企业跨区域投资的促进作用越明显;拓展性研究表明,在投资区位选择上,良好的ESG表现会促使企业资本由经济发达地区向经济欠发达地区流动,在投资模式上,相较于并购投资模式,良好的ESG表现会促使企业更倾向选择新建投资模式进行跨区域投资。研究结果对优化企业跨区域投资策略,推动区域经济协同发展具有重要借鉴价值。

输电铁塔装配式基础抗剪键连接的剪切性能

预制构件连接方法及其界面剪切性能影响整个输电铁塔装配式基础的受力和变形.针对螺栓连接易松动、变形大之类的问题,提出采用高强灌浆料灌注成形的十字形抗剪键作为输电铁塔装配式基础连接方案.采用室内剪切试验和数值模拟,研究该抗剪键连接的剪切性能,并与常用的螺栓连接进行对比分析.结果表明:十字形抗剪键剪切破坏模式为剪断型脆性破坏,破坏形态表现为以抗剪键为中心向外略有扩展成菱形.和螺栓连接相比,抗剪键连接的剪切强度略低,但剪切刚度显著提高.浇筑过程中灌浆料外溢对界面抗剪强度有提高作用.抗剪键的抗剪性能与灌浆料强度正相关,但提高灌浆料强度对抗剪性能提升并不明显.抗剪键深度对抗剪性能有影响,但在抗剪键深度超过20 mm后,抗剪键的抗剪性能不再提高.根据剪切试验和数值模拟结果,建议十字形抗剪键设计为长200 mm、宽20 mm、深20 mm.

基于多尺度时空特征和篡改概率改善换脸检测的跨库性能

目前大多DeepFake换脸检测算法过于依赖局部特征,尽管库内检测性能尚佳,但容易出现过拟合,导致跨库检测性能不理想,即泛化性能不够好。有鉴于此,文中提出一种基于多尺度时空特征和篡改概率的换脸视频检测算法,目的是利用假脸视频中广泛存在的帧间时域不连续性缺陷来解决现有检测算法在跨库、跨伪造方式和视频压缩时性能明显下降的问题,改善泛化检测能力。该算法包括3个模块:为检测假脸视频在时域上留下的不连续痕迹,设计了一个多尺度时空特征提取模块;为自适应计算多尺度时空特征之间的时空域关联性,设计了一个三维双注意力机制模块;为预测随机选取的像素点的篡改概率和构造监督掩膜,设计了一个辅助监督模块。将所提出的算法在FF++、DFD、DFDC、CDF等公开大型标准数据库中进行实验,并与基线算法和近期发布的同类算法进行对比。结果显示:文中算法在保持库内平均检测性能优良的同时,跨库检测和抗视频压缩时的综合性能最好,跨伪造方法检测时的综合性能中等偏上。实验结果验证了文中算法的有效性。

10 kV配网耐张型复合绝缘横担研究综述

复合绝缘横担具有轻质高强、绝缘可靠性高且防雷效果优异等特点,正逐步在10 kV配电线路中得到推广应用。围绕配网耐张型复合绝缘横担结构设计、耐久性研究及性能测试三个问题,首先综述10 kV配网耐张型复合绝缘横担的发展现状,指出研究必要性,进而针对其设计依据、现有设计型式、以疲劳振动老化为代表的耐久性研究进展及关键性能测试与评估展开论述,同时分析目前存在的问题及有待解决的困难,最后结合应用情况进行总结与展望,以期为配网耐张型复合绝缘横担的结构优化、性能提升以及后续大规模应用提供参考。

组态视角下中国制造企业跨国并购创新绩效的影响因素研究

聚焦于跨国并购的创新绩效,采用组态视角,揭示中国制造企业跨国并购中多维度因素对跨国并购创新绩效的综合影响机制。选取3个层面的因素,包括环境因素(制度距离和东道国国家风险)、组织因素(并购经验和行业相关性)和技术因素(研发投入和标的方是否为高技术企业)作为跨国并购创新绩效的条件因素,以中国制造企业跨国并购事件为样本进行分析。研究发现,4种组态能够实现跨国并购创新高绩效,以及6种组态会导致跨国并购创新的非高绩效。研究结果证实了变量的因果不对称性,发现对跨国并购创新绩效存在多种殊途同归的前因变量组合,一定程度上弥补了传统实证研究中变量间线性单向关系的不足,从而丰富了跨国并购创新绩效的研究。