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A learning theory of meta learning

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National Science Review 2024年第8期11卷 9-10页

作者： fang Yao School of Mathematical Sciences Peking University

A key feature of human intelligence is the ability to transfer knowledge learned from multiple learning tasks to other similar but different ones. Namely, humans attempt to learn how to generalize, and thus they can tackle a continuous stream of learning tasks. Correspondingly, in real-world applications, it is always crucial to improve learning in a new task by leveraging knowledge transferred from related tasks that have already been learned.

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Kernel Estimators of the ROC Curve with Censored Data

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Acta Mathematicae Applicatae Sinica 2013年第1期29卷 43-54页

作者： fang-fang Bai Yong Zhou Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Statistics and Management Shanghai University of Finance and Economics

Receiver operating characteristic （ROC） curves are often used to study the two sample problem in medical studies. However, most data in medical studies are censored. Usually a natural estimator is based on the Kaplan-Meier estimator. In this paper we propose a smoothed estimator based on kernel techniques for the ROC curve with censored data. The large sample properties of the smoothed estimator are established. Moreover, deficiency is considered in order to compare the proposed smoothed estimator of the ROC curve with the empirical one based on Kaplan-Meier estimator. It is shown that the smoothed estimator outperforms the direct empirical estimator based on the Kaplan-Meier estimator under the criterion of deficiency. A simulation study is also conducted and a real data is analyzed.

关键词： ROC curve smoothed estimator censored data Kaplan-Meier estimator deficiency

ELECTRODEPOSITION OF AMORPHOUS Ni-P ALLOY COATINGS

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中国有色金属学会会刊：英文版 1997年第3期7卷 149-152页

作者： fang, Zhaoheng Inst of Chemical Metallurgy Chinese Acad of Sciences Beijing China

ＥＬＥＣＴＲＯＤＥＰＯＳＩＴＩＯＮＯＦＡＭＯＲＰＨＯＵＳＮｉＰＡＬＬＯＹＣＯＡＴＩＮＧＳ①ＦａｎｇＺｈａｏｈｅｎｇＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｃａｌＭｅｔａｌｕｒｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎ... 详细信息

ＥＬＥＣＴＲＯＤＥＰＯＳＩＴＩＯＮＯＦＡＭＯＲＰＨＯＵＳＮｉＰＡＬＬＯＹＣＯＡＴＩＮＧＳ①ＦａｎｇＺｈａｏｈｅｎｇＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｃａｌＭｅｔａｌｕｒｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｂｅｉｊｉｎｇ１０００８０...

关键词： electrodeposition amorphous alloy coating nickel phosphorus

A solution to parabolic system with the fractional Laplacian

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Applied Mathematics(A Journal of Chinese Universities) 2009年第2期24卷 184-190页

作者： fang Lin fang Dao-yuan Dept. of Math. Zhejiang Univ. Hangzhou 310027 China

The existence of a solution to the parabolic system with the fractional Laplacian （-△） α/2, α 〉 0 is proven, this solution decays at different rates along different time sequences going to infinity. As an application, the existence of a solution to the generalized Navier-Stokes equations is proven, which decays at different rates along different time sequences going to infinity. The generalized Navier-Stokes equations are the equations resulting from replacing -△ in the Navier-Stokes equations by （-△）^m, m〉 0. At last, a similar result for 3-D incompressible anisotropic Navier-Stokes system is obtained.

关键词： parabolic system fractional Laplacian decay rate

Impaired Face Perception in Individuals with Autism Spectrum Disorder: Insights on Diagnosis and Treatment

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Neuroscience Bulletin 2017年第6期33卷 757-759页

作者： Taiyong Bi fang fang School of Management Zunyi Medical University School of Psychological and Cognitive Sciences Peking University

Autism spectrum disorder（ASD）is a neurodevelopment disorder characterized by impaired social interaction and communication along with restricted and repetitive *** a long period of time,ASD was considered to be a rare mental disorder,with a prevalence of less than1/100,***,the prevalence of diagnosed ASD has increased rapidly in recent years to approximately

关键词： As Impaired Face Perception in Individuals with Autism Spectrum Disorder

Nitrogen release and re-adsorption dynamics on crop straw residue during straw decomposition in an Alfisol

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Journal of Integrative Agriculture 2021年第1期20卷 248-259页

作者： LI Ji-fu ZHONG fang-fang Engineering Research Center of Ecology and Agricultural Use of Wetland Ministry of Education/College of AgricultureYangtze UniversityJingzhou 434025P.R.China

Returning crop straw to the field not only improves the nitrogen(N) supplying capacity and N retention of soil but also decreases the amount of rural organic waste and prevents air pollution. Therefore, understanding the mechanisms of the N release and re-adsorption dynamics on crop straw residue during straw decomposition in agricultural soil is important, and this understanding can help us strengthen N fertilizer management during the crop growth period. An on-farm incubation experiment was conducted in the Jianghan Plain in Central China under flooded conditions using the nylon mesh bag method. Results showed that the decomposition rate of crop straw was much faster at the beginning of the incubation stage, whereas it was steady during the later stage with no observed differences among the three types of crop straw. After 120 d of incubation, the cumulative decomposition proportion of rice straw, wheat straw and rape straw was 72.9, 56.2, and 66.9%, respectively. The proportion of N that released from the three crop straws was 52.0, 54.4 and 54.9%, respectively. The zeta potentials and Brunauer, Emmett and Teller(BET) surface area of the rice, wheat and rape straw residues increased gradually as the decomposition period progressed. The water adsorption capacity of the rice straw was significantly affected during the decomposition period. The saturated water adsorption capacity of rice straw was the highest at 30 d of decomposition(4.17 g g^–1) and then decreased slightly. The saturated water adsorption of wheat and rape straws reached the lowest value at 30 d and then gradually increased and became stable. All the results demonstrated that crop straw and straw residue can re-adsorb NH4^+ ions from the surrounding solution. The re-adsorption was affected by the decomposition period and concentration of exogenous NH4^+ and was independent of the crop species via the combined efforts of physical and chemical adsorption, ion exchange and water retention on residue su

关键词： adsorption decomposition nitrogen(N) Alfisol straw substrate

Mitochondrion-anchoring AIEgen with Large Stokes Shift for Imaging-guided Photodynamic Therapy

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Chemical Research in Chinese Universities 2021年第1期37卷 137-142页

作者： fang fang GAO Yuting LUO Liang National Engineering Research Center for Nanomedicine College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhan430074P.R.China Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica School of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074P.R.China

Photosensitizers that can target and accumulate in mitochondria are expected to achieve good therapeutic effects in photodynamic therapy,as mitochondria are the energy generation factory in ***,we designed and synthesized a novel mitochondrion-targeting photosensitizer TPC-Py with aggregation-induced emission characteristics for image-guided photodynamic ***-Py possessed an efficient production of 1O2,with a quantum yield of 11.65%,upon mild white light irradiation(6 mW/cm^(2)).TPC-Py exhibited good biocompatibility under dark condition,but showed remarkable cytotoxicity towards human cervical carcinoma(HeLa)cells with a half maximal inhibitory concentration(IC50)of 3.2µmol/L when exposed to white light irradiation(14.4 J/cm^(2)).In addition,the Stokes shift of TPC-Py was as high as 150 nm,so that it could prevent self-absorption and increase the signal-to-noise ratio of fluorescence *** excellent performance of TPC-Py makes it a promising candidate in imaging-guided clinical PDT for cancer in the near future.

关键词： Photodynamic therapy Photosensitizer Aggregation-induced emission Mitochondria Imaging-guided

Randomized Algorithms for Orthogonal Nonnegative Matrix Factorization

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Journal of the Operations Research Society of China 2023年第2期11卷 327-345页

作者： Yong-Yong Chen fang-fang Xu College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590ShandongChina

Orthogonal nonnegative matrix factorization(ONMF)is widely used in blind image separation problem,document classification,and human face *** model of ONMF can be efficiently solved by the alternating direction method of multipliers and hierarchical alternating least squares *** the given matrix is huge,the cost of computation and communication is too ***,ONMF becomes challenging in the large-scale *** random projection is an efficient method of dimensionality *** this paper,we apply the random projection to ONMF and propose two randomized *** experiments show that our proposed algorithms perform well on both simulated and real data.

关键词： Orthogonal nonnegative matrix factorization Random projection method Dimensionality reduction Augmented lagrangian method Hierarchical alternating least squares algorithm

MC-ICP-MS 测定岩石标准物质的钒同位素组成

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岩矿测试 2025年第1期44卷 63-74页

作者：徐丽怡于慧敏丁昕黄方中国科学技术大学地球和空间科学学院岩石圈演化与环境演变全国重点实验室安徽合肥230026 中国科学院比较行星学卓越创新中心中国科学技术大学安徽合肥230026

随着分析方法的发展和分析精度的提升,钒同位素已经越来越多地被用于各种地质过程研究。为了确保钒同位素分析测试过程中,可以有效地监控数据的准确度和精度,方便国际各实验室之间的数据对比,同时考虑到早期国际上常用美国地质调查局(US... 详细信息

随着分析方法的发展和分析精度的提升,钒同位素已经越来越多地被用于各种地质过程研究。为了确保钒同位素分析测试过程中,可以有效地监控数据的准确度和精度,方便国际各实验室之间的数据对比,同时考虑到早期国际上常用美国地质调查局(USGS)的标准物质面临着库存不足等问题,本文采用多接收电感耦合等离子体质谱仪(MC-ICP-MS)测定了一系列国际地质标准物质和国家地质标准物质的钒同位素组成,δ51V值的测试精度优于0.08‰。本文选取的标准物质主要来自日本地质调查局(GSJ)和中国地质科学院地球物理地球化学勘查研究所(IGGE),包括一个安山岩(JA-1),三个玄武岩(JB-3、JB-1b和GBW07105),一个辉长岩(JGb-1),一个辉绿岩(GBW07123)以及一个土壤(GBW07454),钒含量范围为77~635μg/g,涵盖了目前大部分火成岩和部分土壤等天然样品含量的范围。这些标准物质除了土壤GBW07454,其他标准物质的钒同位素组成未曾被报道。经测量表明,辉长岩标准物质JGb-1具有最高δ51V值,为−1.05‰±0.08‰,安山岩标准物质JA-1具有最低δ51V值,为−0.34‰±0.06‰,其余标准物质的δ51V值变化范围为−0.72‰~−0.81‰,均落在MORB范围内。本文对这些标准物质钒同位素组成的报道,丰富了钒同位素研究的标准物质数据库,有助于未来在更多领域开展钒同位素研究。

关键词：钒同位素火成岩 MC-ICP-MS 标准物质高精度分析方法