检索结果-南通市图书馆

国家电子商务示范城市建设如何缩小城乡收入差距?——基于全国258个地级市的证据

在线全文

学校读者我要写书评

暂无评论

软科学 2024年第3期38卷 70-76,84页

作者：张志新丁鑫刘晓合山东理工大学经济学院山东淄博255022

基于国家电子商务示范城市建设的准自然实验,使用2010—2020年258个地级市面板数据和阿里淘宝村数据,构建多期DID、PSM-DID等模型,实证检验了国家电子商务示范城市建设对城乡收入差距的影响。结果表明:示范城市建设对农村和城市人均可... 详细信息

基于国家电子商务示范城市建设的准自然实验,使用2010—2020年258个地级市面板数据和阿里淘宝村数据,构建多期DID、PSM-DID等模型,实证检验了国家电子商务示范城市建设对城乡收入差距的影响。结果表明:示范城市建设对农村和城市人均可支配收入分别提升15.1%和8.7%,有效缩小了城乡收入差距。机制分析发现:示范城市建设通过促进农村电商发展和带动中低技能就业缩小城乡收入差距。异质性分析得出:示范城市缩小城乡收入差距的作用主要体现在中小城市和南方城市,对大城市和北方城市作用效果不明显。鉴于此,建议在加强已有示范城市建设的基础上,增加中小城市试点,实现试点工作下沉到区县;北方城市要借鉴南方城市电商模式,完善农村地区配套设施,打造农村电商特色;组织公益性就业技能培训,提升农户就业水平。

关键词：电子商务示范城市城乡收入差距多期DID

Improving constraint on Ωfrom SDSS using marked correlation functions

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年

作者： Limin Lai Jiacheng ding Xiaolin Luo Yizhao Yang Zihan Wang Keshi Liu Guanfu Liu xin Wang Yi Zheng Zhaoyu Li Le Zhang Xiaodong Li School of Physics and Astronomy Sun Yat-sen University Zhuhai Campus Department of Astronomy Shanghai Jiao Tong University Department of Astronomy Tsinghua University CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area SYSU Peng Cheng Laboratory

Large-scale structure （LSS） surveys will increasingly provide stringent constraints on our cosmological ***,the density-marked correlation function （MCF） has been introduced,offering an easily computable density-correlation *** have demonstrated that MCFs offer additional,independent constraints on cosmological models beyond the standard two-point correlation （2PCF）.In this study,we apply MCFs for the first time to SDSS CMASS data,aiming to investigate the statistical information regarding clustering and anisotropy properties in the Universe and assess the performance of various weighting schemes in MCFs,and finally obtain constraints on Ω*** analyzing the CMASS data,we observe that,by combining different weights （α=[-0.2,0,0.2,0.6]）,the MCFs provide a tight and independent constraint on the cosmological parameter Ωm,yielding Ωm=0.293±0.006 at the 1σlevel,which represents a significant reduction in the statistical error by a factor of 3.4compared to that from *** constraint is consistent with recent findings from the small-scale clustering of BOSS galaxies(Zhai et ***.J.948,99 （2023）) within the 1σ***,we also find that our estimate is lower than the Planck measurements by about 2.6σ,indicating the potential presence of new physics beyond the standard cosmological model if all the systematics are fully *** method outlined in this study can be extended to other surveys and datasets,allowing for the constraint of other cosmological ***,it serves as a valuable tool for forthcoming emulator analysis on the Chinese Space Station Telescope （CSST）.

关键词：

Towards human-leveled vision systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第8期67卷 2331-2349页

作者： ding JianHao HUANG TieJun State Key Laboratory of Multimedia Information Processing School of Computer SciencePeking UniversityBeijing 100871China

The human visual system is a complex and interconnected network comprising billions of neurons. It plays an essential role in translating environmental light stimuli into information that guides and shapes human perception and action. Research on the visual system aims to uncover the underlying neural structure principles of human visual perception and their possible ***, there are two main approaches: biological system analysis and simulation, artificial intelligence models based on deep learning. Here we aim to discuss the two approaches to human-level vision systems. Deep learning has significantly impacted the field of vision with achievements in representation, modeling, and hardware design. However, there is still a significant gap between deep learning models and the human visual system in terms of scalability, transferability, and sustainability. The progress of the biological visual system can help fill the gap by further understanding the properties and functions of different components of the system. We take the efforts of reconstructing the retina as an example to illustrate that even if we are unable to replicate the visual system on a computer right now, we can still learn a lot by combining existing research outcomes in neuroscience. At the end of the paper, we suggest tracing back to gradually build visual systems from the computational counterpart of biological structures to achieve a human-level vision system in the future.

关键词： human-leveled vision system deep learning biological visual system

同方期刊数据库

From London buses to activity trackers:A reflection of 70 years of physical activity research

在线全文

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2024年第6期13卷 736-738页

作者： ding ding Ulf Ekelund Prevention Research Collaboration Sydney School of Public HealthFaculty of Medicine and HealthThe University of SydneyCamperdownNSW 2006Australia Charles Perkins Centre The University of SydneyCamperdownNSW 2006Australia Department of Sports Medicine Norwegian School of Sports SciencesOslo 0806Norway Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0213Norway

In 1953,Morris et al.^(1)published their ground-breaking findings among London bus drivers and conductors,linking physical activity to a major chronic disease for the first *** seminal paper marked the birth of a new field—physical activity epidemiology.^(1)Since then,the field has flourished,evidenced by mounting scientific publications.^(2)Our knowledge about the role of physical activity in disease prevention has expanded from coronary heart disease in Morris et al.’s^(1)initial study to dozens of additional diseases and conditions,such as diabetes,cancers,and dementia.^(3)More than 7 decades and thousands of publications later,we critically reflect on several aspects of the progress in physical activity epidemiology.

关键词： epidemiology prevention linking

在线全文

学校读者我要写书评

暂无评论

重症医学科医院感染的药物预防治疗

协和医学杂志 2024年第3期15卷 506-512页

作者：丁欣王小亭中国医学科学院北京协和医院重症医学科北京100730

重症患者医院感染的发生率高且预后差,药物预防可为特定人群带来获益。对于呼吸机相关性肺炎,可针对特定患者及疾病发病时间,选择全身应用或雾化吸入抗生素预防治疗;对于重症医学科侵袭性曲霉病(invasive aspergillosis, IA)的诊断需重... 详细信息

重症患者医院感染的发生率高且预后差,药物预防可为特定人群带来获益。对于呼吸机相关性肺炎,可针对特定患者及疾病发病时间,选择全身应用或雾化吸入抗生素预防治疗;对于重症医学科侵袭性曲霉病(invasive aspergillosis, IA)的诊断需重新认识,并评估IA高危人群预防性抗真菌治疗的必要性;巨细胞病毒(cytomegalovirus, CMV)再激活在重症患者中并不鲜见,预防性抗病毒治疗可降低CMV再激活的发生率,但能否改善患者的临床结局仍待研究进一步探索。针对重症患者医院感染进行药物预防治疗时,临床医生需对目标人群、药物种类及用药方式等因素开展充分的风险-效益评估。

关键词：重症医学医院感染药物预防

New advances in the study of Tethyan Geodynamic System

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第3期67卷 874-878页

作者： Lin ding State Key Laboratory of Tibetan Plateau Earth System Science(LATPES) Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Tethyan Ocean was initially proposed by Austrian geologist Eduard Suess in 1893. The study of the Tethyan evolution by European geologists has led to the development of modern geology, but not to the establishment of plate tectonics theory(Trümpy, 2001). With the progress in various studies, the concept of Tethys has evolved from a Mesozoic ocean into three long-term evolving oceans:Proto-Tethys, Paleo-Tethys, and Neo-Tethys (Figure 1), and their life cycles cover the entire Phanerozoic era (Wu et al., 2020).

关键词： geology Mesozoic ocean

Equivalent linear model for seismic damage evaluation of single-degree-of-freedom systems representing reinforced concrete structures considering cyclic degradation behavior

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第3期23卷 637-648页

作者： Lulu Yan ding-Hao Yu Research Center for Geotechnical and Structural Engineering Technology of Liaoning Province Dalian UniversityDalian116622China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

In this study,a novel equivalent damping ratio model that is suitable for reinforced concrete(RC)structures considering cyclic degradation behavior is developed,and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is *** this end,Ibarra’s peak-oriented model,which incorporates an energy-based degradation rule,is selected for representing hysteretic behavior of RC structure,and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method,in which the effect of cyclic degradation is ***,the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage *** to the simplicity of the equivalent linearization method,the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC *** verification demonstrates the validity of the proposed method.

关键词： degrading system equivalent linear system equivalent damping seismic damage RC structures

在线全文

学校读者我要写书评

暂无评论

无锚双注意力孪生网络的视觉跟踪

控制与决策 2024年第2期39卷 633-640页

作者：郭文梁卜文丁昕苗山东工商学院计算机科学与技术学院山东烟台264005 山东工商学院信息与电子工程学院山东烟台264005

针对跟踪过程中因光照变化、快速运动及尺度变化等造成的角点定位精准度下降问题,受SiamCAR的跟踪框架启发提出一种无锚双注意力孪生网络的视觉跟踪算法.首先,算法的主干网络采用ResNet-50并结合增强多层融合特征图进行特征提取,充分利... 详细信息

针对跟踪过程中因光照变化、快速运动及尺度变化等造成的角点定位精准度下降问题,受SiamCAR的跟踪框架启发提出一种无锚双注意力孪生网络的视觉跟踪算法.首先,算法的主干网络采用ResNet-50并结合增强多层融合特征图进行特征提取,充分利用网络浅层特征的定位信息和深层次的语义信息,提高算法对目标特征的语义理解能力;然后,构建混合注意力模块缓解无锚跟踪器角点定位不准确问题,提高算法的跟踪准确性和定位精度;最后,在GOT10K、UAV123、LaSOT等数据集上进行广泛实验,并与当前的先进跟踪器进行比较,该算法可以较好地抵抗光照变化、快速运动及尺度变化等多种复杂因素带来的影响,同时,在多项评测指标上获得了良好的跟踪性能.

关键词：无锚注意力特征图双注意力孪生网络视觉跟踪

源-荷-储协同优化的配电网平衡能力提升方法

在线全文

学校读者我要写书评

暂无评论

中国电机工程学报 2024年第13期44卷 5097-5108,I0007页

作者：顾光荣杨鹏汤波王丁来鑫上海电力大学电气工程学院上海市杨浦区200090 国网河南省电力公司信阳供电公司河南省信阳市464000 上海理工大学机械工程学院上海市杨浦区200092

在新型电力系统建设背景下,针对分布式新能源和柔性负荷大量接入导致配电网供需情况日益复杂、功率和能量平衡愈加困难等问题,该文提出一种源-荷-储协同优化的配电网平衡能力提升方法,从经济性与用能低碳性等方面提高配电网运行水平。首... 详细信息

在新型电力系统建设背景下,针对分布式新能源和柔性负荷大量接入导致配电网供需情况日益复杂、功率和能量平衡愈加困难等问题,该文提出一种源-荷-储协同优化的配电网平衡能力提升方法,从经济性与用能低碳性等方面提高配电网运行水平。首先,建立多场景下的源荷不确定性模型,在有效量化配电网源荷不确定性的基础上提取典型运行场景;其次,提出一种基于信息熵理论的源荷功率时序平衡度量化评估方法;最后,建立源-荷-储协同的两阶段优化模型,第1阶段通过事件驱动机制深入挖掘用户参与需求响应的潜力,第2阶段在储能系统建模时引入平衡度约束以促进新能源消纳,进而使配电网的平衡能力得到最大程度提升。通过浙江某地区电网实例验证所提方法对提升配电网平衡能力和新能源消纳能力的科学性和实用性。

关键词：源-荷-储协同配电网平衡能力源荷不确定性信息熵理论事件驱动

维普期刊数据库博看期刊