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Machine learning model comparison and ensemble for predicting different morphological fractions of heavy metal elements in tailings and mine waste
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作者 FENG Yu-xin HU Tao +4 位作者 ZHOU Na-na ZHOU Min BARKHORDARI Mohammad Sadegh LI Ke-chao QI Chong-chong 《Journal of Central South University》 2025年第9期3557-3573,共17页
Driven by rapid technological advancements and economic growth,mineral extraction and metal refining have increased dramatically,generating huge volumes of tailings and mine waste(TMWs).Investigating the morphological... Driven by rapid technological advancements and economic growth,mineral extraction and metal refining have increased dramatically,generating huge volumes of tailings and mine waste(TMWs).Investigating the morphological fractions of heavy metals and metalloids(HMMs)in TMWs is key to evaluating their leaching potential into the environment;however,traditional experiments are time-consuming and labor-intensive.In this study,10 machine learning(ML)algorithms were used and compared for rapidly predicting the morphological fractions of HMMs in TMWs.A dataset comprising 2376 data points was used,with mineral composition,elemental properties,and total concentration used as inputs and concentration of morphological fraction used as output.After grid search optimization,the extra tree model performed the best,achieving coefficient of determination(R2)of 0.946 and 0.942 on the validation and test sets,respectively.Electronegativity was found to have the greatest impact on the morphological fraction.The models’performance was enhanced by applying an ensemble method to the top three optimal ML models,including gradient boosting decision tree,extra trees and categorical boosting.Overall,the proposed framework can accurately predict the concentrations of different morphological fractions of HMMs in TMWs.This approach can minimize detection time,aid in the safe management and recovery of TMWs. 展开更多
关键词 tailings and mine waste morphological fractions model comparison machine learning model ensemble
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A Comparison study of First and Second Language Acquisition 被引量:2
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作者 赵健 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2002年第S1期339-341,共3页
More focuses of foreign language teaching theory and practice are on the study of first language and second language acquisition. The article deals with the concept of first and second language acquisition, the relati... More focuses of foreign language teaching theory and practice are on the study of first language and second language acquisition. The article deals with the concept of first and second language acquisition, the relationship between them and the factors influencing on them. The characteristics of the children acquisition and adult acquisition are also studied. 展开更多
关键词 first language acquisition second language acquisition comparison study
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Marginal optimization method to improve the inconsistent comparison matrix in the analytic hierarchy process 被引量:11
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作者 Shihui Wu Jiang Xie +3 位作者 Xiaodong Liu Bo He Minxiang Yang Zhengxin Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第6期1141-1151,共11页
To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(... To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(CR) as benefit, and the maximum modification compared to the original pairwise comparison matrix(PCM) as cost, then the improvement of consistency is transformed to a benefit/cost analysis problem. According to the maximal marginal effect principle, the elements of PCM are modified by a fixed increment(or decrement) step by step till the consistency ratio becomes acceptable, which can ensure minimum adjustment to the original PCM so that the decision makers’ judgment is preserved as much as possible. The correctness of the proposed method is proved mathematically by theorem. Firstly, the marginal benefit/cost ratio is calculated for each single element of the PCM when it has been modified by a fixed increment(or decrement).Then, modification to the element with the maximum marginal benefit/cost ratio is accepted. Next, the marginal benefit/cost ratio is calculated again upon the revised matrix, and followed by choosing the modification to the element with the maximum marginal benefit/cost ratio. The process of calculating marginal effect and choosing the best modified element is repeated for each revised matrix till acceptable consistency is reached, i.e., CR<0.1. Finally,illustrative examples show the proposed method is more effective and better in preserving the original comparison information than existing methods. 展开更多
关键词 analytic hierarchy process(AHP) comparison matrix CONSISTENCY marginal optimization
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New Method for Constructing Comparison Matrix Based on the Proportion Scales in the AHP 被引量:3
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作者 Huang Decai & Shen Liangzhong College of Informaton Engineering, Zhejiang University of Technology, Hangzhou 310032, P. R. China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第3期8-13,共6页
The main faults existing in current scale methods are that the scales do not represent the real importance of alternatives and their relations. This paper presents a proportion judgment scale and introduces a new meth... The main faults existing in current scale methods are that the scales do not represent the real importance of alternatives and their relations. This paper presents a proportion judgment scale and introduces a new method based on the proportion scale for construction comparison matrix in the analytic hierarchy process (AHP). The proportion judgment scales do not have the faults existing in current scale methods and the comparison matrix constructed by the new scale 展开更多
关键词 AHP Judgment scales comparison matrix Consistency checking.
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Global Comparisons of Geological Heritages in Alxa and Establishment of Global Geopark
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作者 Yuhuan Geng~(1,2),Mingzhong Tian~1,Siwen Liu~1,Guoqing Zhang~1,Jing Guo~1 1.School of the Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China. 2.Department of Geography,McGill University,Montreal,Quebec H3A2K6,Canada 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期299-299,共1页
Alxa,located at the junction of the North China plate and the Tarim plate,is characterized by complicated geological conditions and obvious climate changes.Unique geological and geographic conditions formed a variety ... Alxa,located at the junction of the North China plate and the Tarim plate,is characterized by complicated geological conditions and obvious climate changes.Unique geological and geographic conditions formed a variety of landscapes in Alxa, including desert landscape,Gobi landscape,wind -erosion landform,canyon landform,etc.This paper compares and evaluates the scientific interests 展开更多
关键词 Alxa GEOLOGICAL heritages GEOPARK comparison
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The Comparison of Chinese and Western Cultures from the Perspective of Chinese Culture “Going Global”: With Confucius and Socrates’ Thoughts as Examples
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作者 Xie Caihong 《学术界》 CSSCI 北大核心 2019年第4期226-235,共10页
Chinese culture “going global” is an inevitable requirement for China’s economic and social development.As an important part of Chinese traditional culture,the dissemination of Confucian thought is just the spread ... Chinese culture “going global” is an inevitable requirement for China’s economic and social development.As an important part of Chinese traditional culture,the dissemination of Confucian thought is just the spread of Chinese culture.Therefore,the spread of Chinese Confucian thought abroad is also the key to Chinese culture “going global”.However,there are some cultural hinders between China and the West due to the differences in cultures.On the basis of summarizing Confucius and Socrates’ thoughts,this paper analyzes their essence of thoughts by contrast,which represent the eastern and Western cultures respectively.From the perspective of cross-cultural communication,the paper adopts the methods of multiculturalism,criticism and down-to-earth attitudes to deal with Chinese and Western cultures in order to make Chinese go global and share China’s wisdom with the world. 展开更多
关键词 CHINESE culture GOING GLOBAL Confucianism the comparison of CHINESE and Western cultures multiculturalism criticism and inheritance
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Comparison of time optimal control for two level quantum systems
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作者 Shuang Cong Jie Wen Xubo Zou 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第1期95-103,共9页
The time optimal problem for a two level quantum sys-tem is studied. We compare two different control strategies of bang-bang control and the geometric control, respectively, es-pecial y in the case of minimizing the ... The time optimal problem for a two level quantum sys-tem is studied. We compare two different control strategies of bang-bang control and the geometric control, respectively, es-pecial y in the case of minimizing the time of steering the state from North Pole to South Pole on the Bloch sphere with bounded control. The time performances are compared for different param-eters by the individual numerical simulation experiments, and the experimental results are analyzed. The results show that the ge-ometric control spends less time than the bang-bang control does. 展开更多
关键词 geometric control bang-bang control time optimal comparison
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Quantitative comparison of similarity measure and entropy for fuzzy sets
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作者 JUNG Dong-yean CHOI Jung-Wook +1 位作者 PARK Wook-Je LEE Sang-Hyuk 《Journal of Central South University》 SCIE EI CAS 2011年第6期2045-2049,共5页
Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy ... Comparison and data analysis with the similarity measures and entropy for fuzzy sets were carried out. The distance proportional value between the fuzzy set and the corresponding crisp set was considered by the fuzzy entropy. The relation between the similarity measure and the entropy for fuzzy set was also analyzed. The fuzzy entropy was reformulated as the dissimilarity measure. Furthermore, crisp set having the minimum uncertainty with respect to the corresponding fuzzy set was also proposed. Finally, derivation of a similarity measure from entropy with the help of total information property was derived. A simple example shows the relation between similarity measure and fuzzy entropy, in which the summation of similarity measure and fuzzy entropy represents a constant value. 展开更多
关键词 similarity measure fuzzy entropy minimum uncertainty quantitative comparison
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Research on consistency measurement and weight estimation approach of hybrid uncertain comparison matrix
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作者 Zhu Jianjun Zhu Ningning Liu Sifeng Li Tao Wang Hehua 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1145-1150,共6页
The consistency measurement and weight estimation approach of the hybrid uncertain comparison matrix in the analytic hierarchy process (AHP) are studied. First, the decision-making satisfaction membership function i... The consistency measurement and weight estimation approach of the hybrid uncertain comparison matrix in the analytic hierarchy process (AHP) are studied. First, the decision-making satisfaction membership function is defined based on the decision making's allowable error. Then, the weight model based on the maximal satisfactory consistency idea is suggested, and the consistency index is put forward. Moreover, the weight distributing value model is developed to solve the decision making misleading problem since the multioptimization solutions in the former model. Finally, the weights are ranked based on the possibility degree approach to obtain the ultimate order. 展开更多
关键词 analytic hierarchy process uncertainty hybrid comparison matrix weight
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Comparison between the 2007 and the 2016 WHO classification of tumours of the central nervous system
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《中国现代神经疾病杂志》 CAS 2016年第8期543-543,共1页
关键词 comparison between the 2007 and the 2016 WHO classification of tumours of the central nervous system NOS WHO
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Comparison between the 2007 and the 2016 WHO Classification of Tumours of the Central Nervous System
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《中国现代神经疾病杂志》 CAS 2016年第6期381-381,共1页
关键词 WHO IDH comparison between the 2007 and the 2016 WHO Classification of Tumours of the Central Nervous System
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Comparison between the 2007 and the 2016 WHO classification of tumours of the central nervous system(Ⅰ)
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《中国现代神经疾病杂志》 CAS 2016年第10期719-719,共1页
关键词 WHO comparison between the 2007 and the 2016 WHO classification of tumours of the central nervous system
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The Comparison of Ten Biggest Distance Education Institutions in the World
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《开放教育研究》 1995年第1期54-54,共1页
The 1995 International Council of Distance Education(ICDE)In Blrmingham,Britain selected ten(llstance education mstltutlons with an enrollment of over 100,000Inthe world. Theyrespectively belong to China,阶ance... The 1995 International Council of Distance Education(ICDE)In Blrmingham,Britain selected ten(llstance education mstltutlons with an enrollment of over 100,000Inthe world. Theyrespectively belong to China,阶ance,India,Indonesia, 展开更多
关键词 The comparison of Ten Biggest Distance Education Institutions in the World ICDE
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A Comparison of Carlin-type Gold Deposits:Guizhou Province,Golden Triangle,Southwest China,and Northern Nevada,USA 被引量:29
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作者 Jean S.CLlNE John L.MUNTEAN +1 位作者 Xuexiang GU Yong XIA 《地学前缘》 EI CAS CSCD 北大核心 2013年第1期1-18,共18页
Several Au deposits in Guizhou Province,southwest China,described as being similar to the highly productive Carlin-type gold deposits in northern Nevada.USA,were examined to identify similarities and differences betwe... Several Au deposits in Guizhou Province,southwest China,described as being similar to the highly productive Carlin-type gold deposits in northern Nevada.USA,were examined to identify similarities and differences between the two districts.Samples were collected along transects from lowto high-grade rock,where possible,and fram stockpiles at the Shuiyindong,Zimudang,Taipingdong,Yata and Jinfeng(formerly Lannigou)deposits.Methods used to examine ore and alteration minerals included hand-sample description:reflectance spectroscopy using an ASD Terraspec spectrometer;analyses of hand samples by carbonate staining with Alizaren red and potassium ferricyanide;transmitted and reflected light petrography;chemical analyses,mineral identification,and imaging using a JEOL.JSM-5610 scanning electron microscope:and quantitative chemical analyses using a JEOL JXA-8900 electron probe microanalyzer.Geochemical analyses of hand samples for 52 elements were done by ALS Chemex.Results indicate both similarities and differences between the two districts.Both districts have similar geologic histories.and deposits at both locations appear to have formed as a result of similar tectonic events.though the district in southwest China lacks evidence of eoeval felsic igneous activity;however,the ore-stage minerals and the fluids that produced the minerals and deposits have some significant differences.The Nevada deposits were dominated by fluid-rock reaction in which host rock Fe was sulfidized to form Au-bearing pyrite.Although ore fluids sulfidized host rock Fe in the Cuizhou deposits.the timing of Fe metasomatism is unknown,so whether the deposits formed in response to sulfidation or pyritization is unclear.Fluid-rock reaction between an acidic,aqueous fluid and highly reactive calcareous rocks in Nevada caused extensive decarbonatization of host rocks,jasperoid replacemerit of carbonate minerals,and alteration of silty rock components to illite and kaolinite.In Guizhou,CO2-bearing ore fluids with temperatures and pressures approaching 100℃ and 500 bars greater than temperatures and pressures detemained for ore fluids in the Nevada deposits,deposited Aubearing pyrite.In examined Guizhou deposits these fluids carbonatized host rocks and farmed both replacement and open-space-filling ore.The fluids,which may have been immiscible,were sufficiently overpressured to fracture wall rocks and to create significant open space filled by vein quartz.While deposit architecture,tectonic setting,and host rocks in Guizhou are quite similar to northern Nevada,ore and alteration minerals suggest that ore-forming processes in examined Guizhou deposits have important similarities to processes associated with formation of orogenic Au systems.The Guizhou deposits display characteristics of both Carlin-type and orogenic systems,perhaps indicating formation at conditions somewhat intermediate to conditions for Carlin-type deposits and orogenic systems. 展开更多
关键词 地质 地理学 地质构造 气藏
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光谱辐射照度国际关键比对装置、方法与结果分析 被引量:1
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作者 代彩红 王彦飞 +2 位作者 李玲 吴志峰 谢一航 《光谱学与光谱分析》 SCIE EI CAS 北大核心 2025年第1期1-7,共7页
基于高温黑体辐射源和双光栅光谱辐射比较测量系统,中国计量科学研究院自主研制了新一代光谱辐射照度国家基准装置,波长范围覆盖230~2550 nm,以一组稳定的卤钨灯作为副基准灯组,保存和传递光谱辐射照度量值。黑体的温度溯源至铂-碳Pt-C... 基于高温黑体辐射源和双光栅光谱辐射比较测量系统,中国计量科学研究院自主研制了新一代光谱辐射照度国家基准装置,波长范围覆盖230~2550 nm,以一组稳定的卤钨灯作为副基准灯组,保存和传递光谱辐射照度量值。黑体的温度溯源至铂-碳Pt-C和铼-碳Re-C共晶点黑体,在3021 K采用钨碳-碳WC-C共晶点黑体进行验证。采用新基准装置,2017年-2019年NIM参加国际计量局组织的光谱辐射照度国际关键比对CCPR-K1.a,比对由全俄光学物理学测量研究院(VNIIOFI)主导,共有12个实验室参加。比对结果表明:除少数实验室外,在250~290、300~1300、1500~2500 nm波长范围,各参比实验室之间的一致性分别为±2.0%、±1.0%和±2.0%。在紫外、可见和近红外波段,NIM与国际比对参考值的平均相对偏差分别为0.13%、0.28%和0.15%。在250~2500 nm全波段,NIM与国际比对参考值的平均相对偏差为0.17%,与2004年平均相对偏差0.9%相比,测量能力提升显著。 展开更多
关键词 光谱辐射照度 国际比对 高温黑体 测量不确定度 国家基准
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食用植物油安全标准的国内外比较分析(一)——体系、结构、范围和分类对比 被引量:2
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作者 赵晨伟 金青哲 王兴国 《粮油食品科技》 北大核心 2025年第4期1-6,共6页
本文从标准体系、文本结构、范围和分类4个方面系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的差异。结果发现:标准体系方面,各国... 本文从标准体系、文本结构、范围和分类4个方面系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的差异。结果发现:标准体系方面,各国按其国情制定了各自的植物油安全标准;标准文本结构方面,各国的食用植物油标准绝大多数包含了范围、理化指标、安全指标、标签等相关规定;范围和分类方面,各国的标准基本上涵盖了常见的植物油,并根据国情、依据加工深度或工艺做了不同的分类。这一分析可为中国食用植物油安全标准的制修订提供参考,以进一步完善中国食用植物油安全标准,保障消费者健康。 展开更多
关键词 食用植物油 标准体系 文本结构 范围 分类 国内外比较
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食用植物油安全标准的国内外比较分析(二)——理化指标对比 被引量:2
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作者 赵晨伟 金青哲 王兴国 《粮油食品科技》 北大核心 2025年第4期7-12,共6页
本文系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的酸价、过氧化值、溶剂残留量、游离棉酚、煎炸油废弃点等理化指标的差异。分析... 本文系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的酸价、过氧化值、溶剂残留量、游离棉酚、煎炸油废弃点等理化指标的差异。分析发现:酸价方面,仅中国、CAC、印度、俄罗斯规定了原油的酸价,中国的食用植物油酸价指标与国外标准基本一致;过氧化值方面,仅中国规定了原油的过氧化值,中国的食用植物油过氧化值指标比国外标准高;溶剂残留方面,仅中国、CAC、欧盟、新加坡、印度和韩国做了规定,中国的限值高于国外标准;棉酚方面,仅中国对其做了规定;极性组分方面,中国的限量值比国外标准高。建议在我国的食用植物油国家安全标准修订中,调整过氧化值、溶剂残留、棉酚和极性组分的限值。 展开更多
关键词 食用植物油 标准 理化指标 酸价 过氧化值 极性组分 国内外比较
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食用植物油安全标准的国内外比较分析(三)——安全指标对比 被引量:1
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作者 赵晨伟 金青哲 王兴国 《粮油食品科技》 北大核心 2025年第4期13-22,共10页
本文从污染物限量、真菌毒素限量、食品添加剂限量和农药残留限量4个安全指标层面系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的... 本文从污染物限量、真菌毒素限量、食品添加剂限量和农药残留限量4个安全指标层面系统对比了中国与国际食品法典委员会、欧盟、美国、日本、澳大利亚与新西兰、新加坡、印度、韩国和俄罗斯等国际组织、国家和地区食用植物油安全标准的差异。结果发现:污染物方面,污染物种类少于国外标准,重金属限量与国外基本一致,苯并[a]芘的限值宽松于国外;真菌毒素方面,中国对花生油、玉米油中黄曲霉毒素B1的限量宽松于国外标准;食品添加剂方面,中国与CAC标准在指标上整体处于同一水平,在种类上,中国数量偏少一些;在农药最大残留量标准方面,中国在食用植物油的农药残留规定的种类远多于其他国家,在限量上也严格于其他国家,仅有3种农药高于其他国家。建议我国在后续相关标准修订中,对苯并[a]芘、3-氯丙醇酯、缩水甘油酯、黄曲霉毒素B1等指标进行调整,并增加玉米赤霉烯酮限值。 展开更多
关键词 食用植物油 标准 污染物 真菌毒素 食品添加剂 农药残留 国内外比较
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基于标准的国家智慧教育平台调优:国际方位与发展路径 被引量:6
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作者 曹培杰 来枭雄 +1 位作者 周帆 李永智 《电化教育研究》 北大核心 2025年第1期40-46,共7页
研究以大规模创新性应用为导向,构建了包括广泛联结、融合创新、机制保障、素养提升等4个一级维度、12个二级维度、35个观测点的国家智慧教育平台应用标准。依据标准对国内外16个代表性智慧教育平台开展比较分析。研究发现:中国国家智... 研究以大规模创新性应用为导向,构建了包括广泛联结、融合创新、机制保障、素养提升等4个一级维度、12个二级维度、35个观测点的国家智慧教育平台应用标准。依据标准对国内外16个代表性智慧教育平台开展比较分析。研究发现:中国国家智慧教育平台建设与应用水平居世界前列,在平台接入、资源汇聚、应用集成和组织统筹方面处于“领跑”位置,在常态应用和终身学习方面处于“并跑”位置,在流程优化、督促激励和支撑保障方面处于“跟跑”位置。研究建议完善国家智慧教育平台体系建设、构建优质数字资源创生汇聚机制、聚焦教育教学关键环节丰富应用场景、构建以“国家平台+”为核心的数字教育新生态。 展开更多
关键词 智慧教育平台 应用标准 国际比较 教育数字化 发展路径
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人工智能教育应用政策的差异、共识与趋向——基于中、日、英、美四国比较 被引量:5
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作者 罗江华 钟文俊 陈艺 《现代远程教育研究》 北大核心 2025年第1期73-83,共11页
人工智能在教育领域的应用为教育变革提供了动力,其相关政策成为引领教育数字化转型的风向标。对人工智能教育应用政策进行国际比较研究,有助于增强人们对全球教育技术发展趋势的全局性理解,并帮助政策制定者设计更具前瞻性和适应性的... 人工智能在教育领域的应用为教育变革提供了动力,其相关政策成为引领教育数字化转型的风向标。对人工智能教育应用政策进行国际比较研究,有助于增强人们对全球教育技术发展趋势的全局性理解,并帮助政策制定者设计更具前瞻性和适应性的政策框架。通过比较分析中、日、英、美四国近年来发布的相关政策文本发现,各国均日益重视人工智能在教育中的普及应用,但其对政策工具的选择和政策目标的设定存在显著差异。在政策工具整体结构方面,中国偏向于供给型政策工具,强调直接供给,注重基础设施建设与人才培养项目等投入;而日、英、美三国倾向于环境型工具,致力于营造支持性环境。在政策目标实现的策略层面,中国采用“专注聚焦”模式,而日、英、美三国则强调“平衡多元”。尽管存在上述差异,但四国在强化教育科技领军人才的培养机制、建立多元主体协作参与的保障体系,以及打造高质量且包容的数字教育生态方面已形成发展共识。从全球趋势来看,未来世界各国对教育科技领域人才的培养和竞争将日益加剧,而各国可能会形成敏捷治理的政策框架,并利用人工智能增进教育的广泛包容性,同时产学研合作将持续引领智能教育技术的本土创新。 展开更多
关键词 人工智能 教育应用 政策比较 政策工具 政策目标
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