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Flood predictions from metrics to classes by multiple machine learning algorithms coupling with clustering-deduced membership degree
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作者 ZHAI Xiaoyan ZHANG Yongyong +5 位作者 XIA Jun ZHANG Yongqiang TANG Qiuhong SHAO Quanxi CHEN Junxu ZHANG Fan 《Journal of Geographical Sciences》 2026年第1期149-176,共28页
Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting... Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting flood resource variables using single or hybrid machine learning techniques.However,class-based flood predictions have rarely been investigated,which can aid in quickly diagnosing comprehensive flood characteristics and proposing targeted management strategies.This study proposed a prediction approach of flood regime metrics and event classes coupling machine learning algorithms with clustering-deduced membership degrees.Five algorithms were adopted for this exploration.Results showed that the class membership degrees accurately determined event classes with class hit rates up to 100%,compared with the four classes clustered from nine regime metrics.The nonlinear algorithms(Multiple Linear Regression,Random Forest,and least squares-Support Vector Machine)outperformed the linear techniques(Multiple Linear Regression and Stepwise Regression)in predicting flood regime metrics.The proposed approach well predicted flood event classes with average class hit rates of 66.0%-85.4%and 47.2%-76.0%in calibration and validation periods,respectively,particularly for the slow and late flood events.The predictive capability of the proposed prediction approach for flood regime metrics and classes was considerably stronger than that of hydrological modeling approach. 展开更多
关键词 flood regime metrics class prediction machine learning algorithms hydrological model
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Quantum Geometric Tensor for Mixed States Based on the Covariant Derivative
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作者 Qianyi Wang Ben Wang +1 位作者 Jun Wang Lijian Zhang 《Chinese Physics Letters》 2025年第7期171-181,共11页
The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned... The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned only for pure states,has limited applicability in realistic scenarios where mixed states are common.To address this limitation,we generalize the defnition of the QGT to mixed states using the purifcation bundle and the covariant derivative.Notably,our proposed defnition reduces to the traditional QGT when mixed states approach pure states.In our framework,the real and imaginary parts of this generalized QGT correspond to the Bures metric and the mean gauge curvature,respectively,endowing it with a broad range of potential applications.Additionally,using our proposed mixed-state QGT,we derive the geodesic equation applicable to mixed states.This work establishes a unifed framework for the geometric analysis of both pure and mixed states,thereby deepening our understanding of the geometric properties of quantum states. 展开更多
关键词 characterizing geometric properties quantum states purifcation bundle elucidating various physical phenomenathe covariant derivative Bures metric quantum geometric tensor qgt quantum geometric tensor mixed states
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Quantum Metric, Topology and Second Harmonic Generation
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作者 En Wang Yaxian Wang Sheng Meng 《Chinese Physics Letters》 2025年第4期99-113,共15页
The quantum metric manifested as the Riemannian metric in the parameter space of Bloch bands,characterizes the topology and geometry of quantum states.The second harmonic generation(SHG),as one of the fundamental nonl... The quantum metric manifested as the Riemannian metric in the parameter space of Bloch bands,characterizes the topology and geometry of quantum states.The second harmonic generation(SHG),as one of the fundamental nonlinear optical responses that links geometry of optical transitions to physical observables,despite being widely studied in various materials,its relation to quantum metric,especially in the dynamical regime,stays obscure. 展开更多
关键词 second harmonic generation shg quantum metric quantum metricespecially geometry optical transitions nonlinear optical responses bloch bandscharacterizes riemannian metric TOPOLOGY
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GÂTEAUX DIRECTIONAL DIFFERENTIABILITY OF THE GENERALIZED METRIC PROJECTION IN BANACH SPACES
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作者 Jinlu LI 《Acta Mathematica Scientia》 2025年第4期1597-1618,共22页
Let X be a real uniformly convex and uniformly smooth Banach space and C a nonempty closed and convex subset of X.Let Π_(C):X→C denote the generalized metric projection operator introduced by Alber in[1].In this pap... Let X be a real uniformly convex and uniformly smooth Banach space and C a nonempty closed and convex subset of X.Let Π_(C):X→C denote the generalized metric projection operator introduced by Alber in[1].In this paper,we define the Gâteaux directional differentiability of Π_(C).We investigate some properties of the Gâteaux directional differentiability of Π_(C).In particular,if C is a closed ball,or a closed and convex cone(including proper closed subspaces),or a closed and convex cylinder,then,we give the exact representations of the directional derivatives of Π_(C).By comparing the results in[12]and this paper,we see the significant difference between the directional derivatives of the generalized metric projection operator Π_(C) and the Gâteaux directional derivatives of the standard metric projection operator PC. 展开更多
关键词 uniformly convex and uniformly smooth Banach space the generalized metric projection directional differentiability of the generalized metric projection directional derivative of the generalized metric projection
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A Survey on the Existence of Harmonic Metrics on Vector Bundles
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作者 SHEN Zhenghan ZHANG Xi 《数学进展》 北大核心 2025年第2期390-404,共15页
In this paper,we give a survey on the existence of Hermitian-Einstein metrics and harmonic metrics.
关键词 Hermitian-Einstein metric harmonic metric holomorphic vector bundle non-Hermitian Yang-Mills bundle
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Some analytic results and applications in extremal Hermitian metrics
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作者 SANG Haoxin WU Yingyi 《中国科学院大学学报(中英文)》 北大核心 2025年第5期589-599,共11页
In this paper,we introduce and prove three analytic results related to uniform convergence,properties of Newtonian potential,and convergence of sequences in Sobolev space constrained by their Laplacian.Then,utilizing ... In this paper,we introduce and prove three analytic results related to uniform convergence,properties of Newtonian potential,and convergence of sequences in Sobolev space constrained by their Laplacian.Then,utilizing our analytic results,we develop a complete proof of a crucial estimate appearing in the results of Guofang Wang and Xiaohua Zhu,which states the classification of extremal Hermitian metrics with finite energy and area on compact Riemann surfaces and finite singularities satisfying small singular angles. 展开更多
关键词 extremal Hermitian metrics conical singularities of metrics Newtonian potential
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EXISTENCE OF SOME SPECIAL CONFORMALLY-KAHLER METRICS ON CERTAIN CP1 BUNDLES
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作者 Jing CHEN Daniel GUAN 《Acta Mathematica Scientia》 2025年第2期525-539,共15页
In this paper,we prove that for certain fiber bundles there is a k-Futaki-Ono conformally Kahler metric related to a metric in any given Kahler class for any k≥2.
关键词 Hermitian metrics conformally-Kahler metrics complex manifolds scalar curvature fiber bundle almost homogeneous manifolds
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Metric Identification of Vertices in Polygonal Cacti
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作者 Xiujun Zhang Muhammad Salman +3 位作者 Anam Rani Rashna Tanveer Usman Ali Zehui Shao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第7期883-899,共17页
The distance between two vertices u and v in a connected graph G is the number of edges lying in a shortest path(geodesic)between them.A vertex x of G performs the metric identification for a pair(u,v)of vertices in G... The distance between two vertices u and v in a connected graph G is the number of edges lying in a shortest path(geodesic)between them.A vertex x of G performs the metric identification for a pair(u,v)of vertices in G if and only if the equality between the distances of u and v with x implies that u=v(That is,the distance between u and x is different from the distance between v and x).The minimum number of vertices performing the metric identification for every pair of vertices in G defines themetric dimension of G.In this paper,we performthemetric identification of vertices in two types of polygonal cacti:chain polygonal cactus and star polygonal cactus. 展开更多
关键词 metric metric identification metric generator metric dimension cactus graph
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The Gravitational Potential and the Gravitational Force According to the Correct Reissner-Nordstrøm, Kerr and Kerr-Newman Metrics
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作者 Carlo Maria Pace 《Journal of Modern Physics》 2025年第1期52-92,共41页
In a recent article, we have corrected the traditional derivation of the Schwarzschild metric, thus obtaining the formulation of the correct Schwarzschild metric, which is different from the traditional Schwarzschild ... In a recent article, we have corrected the traditional derivation of the Schwarzschild metric, thus obtaining the formulation of the correct Schwarzschild metric, which is different from the traditional Schwarzschild metric. Then, in another article by starting from this correct Schwarzschild metric, we have corrected also the Reissner-Nordstrøm, Kerr and Kerr-Newman metrics. On the other hand, in a third article, always by starting from this correct Schwarzschild metric, we have obtained the formulas of the correct gravitational potential and of the correct gravitational force in the case described by this metric. Now, in this article, by starting from these correct Reissner-Nordstrøm, Kerr and Kerr-Newman metrics and proceeding in a manner analogous to this third article, we obtain the formulas of the correct gravitational potential and of the correct gravitational force in the cases described by these metrics. Moreover, we analyze these correct results and their consequences. Finally, we propose some possible crucial experiments between the commonly accepted theory and the same theory corrected according to this article. 展开更多
关键词 General Theory of Relativity SCHWARZSCHILD Reissner-Nordstrøm KERR Kerr-Newman metric Gravitational Potential Gravitational Force Orbital Motion
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Greenness evaluation metric for analytical methods and software
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作者 Tong Xin Luyao Yu +7 位作者 Wenying Zhang Yingxia Guo Chuya Wang Zhong Li Jiansong You Hongyu Xue Meiyun Shi Lei Yin 《Journal of Pharmaceutical Analysis》 2025年第7期1667-1676,共10页
The focus of green analytical chemistry(GAC)is to minimize the negative impacts of analytical procedures on human safety,human health,and the environment.Several factors,such as the reagents used,sample collection,sam... The focus of green analytical chemistry(GAC)is to minimize the negative impacts of analytical procedures on human safety,human health,and the environment.Several factors,such as the reagents used,sample collection,sample processing,instruments,energy consumed,and the quantities of hazardous materials and waste generated during analytical procedures,need to be considered in the evaluation of the greenness of analytical assays.In this study,we propose a greenness evaluation metric for analytical methods(GEMAM).The new greenness metric is simple,flexible,and comprehensive.The evaluation criteria are based on both the 12 principles of GAC(SIGNIFICANCE)and the 10 factors of sample preparation,and the results are presented on a 0–10 scale.The GEMAM calculation process is easy to perform,and its results are easy to interpret.The output of GEMAM is a pictogram that can provide both qualitative and quantitative information based on color and number. 展开更多
关键词 Green analytical chemistry Analytical methods Greenness evaluation metric
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Improving Robustness for Tag Recommendation via Self-Paced Adversarial Metric Learning
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作者 Zhengshun Fei Jianxin Chen +1 位作者 Gui Chen Xinjian Xiang 《Computers, Materials & Continua》 2025年第3期4237-4261,共25页
Tag recommendation systems can significantly improve the accuracy of information retrieval by recommending relevant tag sets that align with user preferences and resource characteristics.However,metric learning method... Tag recommendation systems can significantly improve the accuracy of information retrieval by recommending relevant tag sets that align with user preferences and resource characteristics.However,metric learning methods often suffer from high sensitivity,leading to unstable recommendation results when facing adversarial samples generated through malicious user behavior.Adversarial training is considered to be an effective method for improving the robustness of tag recommendation systems and addressing adversarial samples.However,it still faces the challenge of overfitting.Although curriculum learning-based adversarial training somewhat mitigates this issue,challenges still exist,such as the lack of a quantitative standard for attack intensity and catastrophic forgetting.To address these challenges,we propose a Self-Paced Adversarial Metric Learning(SPAML)method.First,we employ a metric learning model to capture the deep distance relationships between normal samples.Then,we incorporate a self-paced adversarial training model,which dynamically adjusts the weights of adversarial samples,allowing the model to progressively learn from simpler to more complex adversarial samples.Finally,we jointly optimize the metric learning loss and self-paced adversarial training loss in an adversarial manner,enhancing the robustness and performance of tag recommendation tasks.Extensive experiments on the MovieLens and LastFm datasets demonstrate that SPAML achieves F1@3 and NDCG@3 scores of 22%and 32.7%on the MovieLens dataset,and 19.4%and 29%on the LastFm dataset,respectively,outperforming the most competitive baselines.Specifically,F1@3 improves by 4.7%and 6.8%,and NDCG@3 improves by 5.0%and 6.9%,respectively. 展开更多
关键词 Tag recommendation metric learning adversarial training self-paced adversarial training ROBUSTNESS
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Distributional scalar curvature and Einstein metrics
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作者 ZHANG Huai-yu ZHANG Jiang-wei 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第2期458-479,共22页
In this paper,we study scalar curvature rigidity of non-smooth metrics on smooth manifolds with non-positive Yamabe invariant.We prove that if the scalar curvature is not less than the Yamabe invariant in the distribu... In this paper,we study scalar curvature rigidity of non-smooth metrics on smooth manifolds with non-positive Yamabe invariant.We prove that if the scalar curvature is not less than the Yamabe invariant in the distributional sense,then the manifold must be isometric to an Einstein manifold.This result extends Theorem 1.4 in Jiang,Sheng and Zhang[27],from a special case where the manifolds have zero Yamabe invariant to general cases where the manifolds have non-positive Yamabe invariant. 展开更多
关键词 scalar curvature Einstein metric Yamabe invariant
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Protection path and security-metric-based resource allocation algorithm in quantum key distribution optical networks
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作者 Li Liu Shengtong Zhai +1 位作者 Yao Pu Xu Zhang 《Chinese Physics B》 2025年第9期73-83,共11页
Quantum key distribution(QKD)optical networks can provide more secure communications.However,with the increase of the QKD path requests and key updates,network blocking problems will become severe.The blocking problem... Quantum key distribution(QKD)optical networks can provide more secure communications.However,with the increase of the QKD path requests and key updates,network blocking problems will become severe.The blocking problems in the network can become more severe because each fiber link has limited resources(such as wavelengths and time slots).In addition,QKD optical networks are also affected by external disturbances such as data interception and eavesdropping,resulting in inefficient network communication.In this paper,we exploit the idea of protection path to enhance the anti-interference ability of QKD optical network.By introducing the concept of security metric,we propose a routing wavelength and time slot allocation algorithm(RWTA)based on protection path,which can lessen the blocking problem of QKD optical network.According to simulation analysis,the security-metric-based RWTA algorithm(SM-RWTA)proposed in this paper can substantially improve the success rate of security key(SK)update and significantly reduce the blocking rate of the network.It can also improve the utilization rate of resources such as wavelengths and time slots.Compared with the non-security-metric-based RWTA algorithm(NSM-RWTA),our algorithm is robust and can enhance the anti-interference ability and security of QKD optical networks. 展开更多
关键词 quantum key distribution(QKD) optical network security metric protection path
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A Contrastive Analysis of English and Chinese Intonation Systems: An Auto- Segmental Metrical Framework
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作者 Qingbo Tian Ngee Thai Yap +1 位作者 Chwee Fang Ng Yasir Yahya 《Chinese Journal of Applied Linguistics》 2025年第3期366-400,480,481,共37页
Intonation refers to the use of supra-segmental features to convey pragmatic meanings at the sentence level in a linguistically structured way.The difference in intonation between the native language and a foreign lan... Intonation refers to the use of supra-segmental features to convey pragmatic meanings at the sentence level in a linguistically structured way.The difference in intonation between the native language and a foreign language may influence second language learners’acquisition of intonation.The purpose of this study is to explore the similarities and differences at the level of phonological representation between English and Chinese intonation systems.This study investigated English and Chinese intonation systems,respectively,from both form and meaning under the Auto-Segmental Metrical framework by referring to previous studies and illustrating examples.The results showed that in terms of form,there were notable differences in the structural elements and their inventories between the intonation systems of English and Chinese.In terms of meaning,assertions were represented by different structural elements in English and Chinese intonation systems;the types of structural elements in English intonation possessed the capability to convey complex and subtle meanings,contrasting with the comparatively simpler nature of Chinese intonation.The results reveal that Chinese EFL learners demonstrate considerable difficulties in the production of the structural elements of English intonation and their combinations due to L1 intonation interference. 展开更多
关键词 acquisition of L2 intonation auto-segmental metrical framework Chinese intonation cross-linguistic effects English intonation
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Fixed point results for asymptotically regular mappings in abstract metric spaces
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作者 HAN Yan DAI Ting-ting XU Shao-yuan 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第3期632-644,共13页
In this paper,various extended contractions are introduced as generalizations of some existing contractions given by Kannan,Ciric,Reich and Gornicki,et al.Then,several meaningful results about asymptotically regular m... In this paper,various extended contractions are introduced as generalizations of some existing contractions given by Kannan,Ciric,Reich and Gornicki,et al.Then,several meaningful results about asymptotically regular mappings in cone metric spaces over Banach algebras are obtained,weakening the completeness of the spaces and the continuity of the mappings.Moreover,some nontrivial examples are showed to verify the innovation of the new concepts and our fxed point theorems. 展开更多
关键词 asymptotic regularity fixed point cone metric spaces over Banach algebras
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Bibliometrics: tracking research impact by selecting Lhe appropriate metrics 被引量:21
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作者 Ashok Agarwal Damayanthi Durairajanayagam +18 位作者 Sindhuja Tatagari Sandro C Esteves Avi Harlev Ralf Henkel Shubhadeep Roychoudhury Sheryl Homa Nicolas Garrido Puchalt Ranjith Ramasamy Ahmad Majzoub Kim Dao Ly Eva Tvrda Mourad Assidi Kavindra Kesai Reecha Sharma Saleem Banihani Edmund Ko Muhammad Abu-Elmagd Jaime Gosalvez Asher Bashiri 《Asian Journal of Andrology》 SCIE CAS CSCD 2016年第2期296-309,J0008,共15页
Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to as the impact of a ... Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to as the impact of a specific researcher, is assessed through the use of various metrics. While researchers may be acquainted with such matrices, many do not know how to use them to enhance their careers. In addition to these metrics, a number of other factors should be taken into consideration to objectively evaluate a scientist's profile as a researcher and academician. Moreover, each metric has its own limitations that need to be considered when selecting an appropriate metric for evaluation. This paper provides a broad overview of the wide array of metrics currently in use in academia and research. Popular metrics are discussed and defined, including traditional metrics and article-level metrics, some of which are applied to researchers for a greater understanding of a particular concept, including varicocete that is the thematic area of this Special Issue of Asian Journal of Andrology. We recommend the combined use of quantitative and qualitative evaluation using judiciously selected metrics for a more objective assessment of scholarly output and research impact. 展开更多
关键词 article-level metrics BIBLIOmetricS citation counts H-INDEX impact factor research databases research impact research productivity traditional metrics
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The Equivalence between Bergman Metric and Einstein-Kahler Metric on the Cartan-Hartogs Domain of the Fourth Type 被引量:4
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作者 ZHAO Xiao-xia LIN Ping 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第3期317-324,共8页
In this paper, we discuss the invariant complete metric on the Cartan-Hartogs domain of the fourth type. Firstly, we find a new invariant complete metric, and prove the equivalence between Bergman metric and the new m... In this paper, we discuss the invariant complete metric on the Cartan-Hartogs domain of the fourth type. Firstly, we find a new invariant complete metric, and prove the equivalence between Bergman metric and the new metric; Secondly, the Ricci curvature of the new metric has the super bound and lower bound; Thirdly,we prove that the holomorphic sectional curvature of the new metric has the negative supper bound; Finally, we obtain the equivalence between Bergman metric and Einstein-Kahler metric on the Cartan-Hartogs domain of the fourth type. 展开更多
关键词 Cartan-Hartogs domain equivalence of invariant metric Bergman metric Einstein-Kahler metric
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ON A CLASS OF DOUGLAS FINSLER METRICS 被引量:1
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作者 朱红梅 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期695-708,共14页
In this article, we study a class of Finsler metrics called general (α, β)-metrics, which are defined by a Riemannian metric α and a 1-form β. We determine all of Douglas general (α, β)-metrics on a manifold... In this article, we study a class of Finsler metrics called general (α, β)-metrics, which are defined by a Riemannian metric α and a 1-form β. We determine all of Douglas general (α, β)-metrics on a manifold of dimension n 〉 2. 展开更多
关键词 Finsler metric general (α β)-metric Douglas metric
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GENERALIZATIONS OF THE SUZUKI AND KANNAN FIXED POINT THEOREMS IN G-CONE METRIC SPACES 被引量:1
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作者 Mohammad Sadegh Asgari Zohreh Abbasbigi 《Analysis in Theory and Applications》 2012年第3期248-262,共15页
In this paper we develop the Banach contraction principle and Kannan fixed point theorem on generalized cone metric spaces. We prove a version of Suzuki and Kannan type generalizations of fixed point theorems in gener... In this paper we develop the Banach contraction principle and Kannan fixed point theorem on generalized cone metric spaces. We prove a version of Suzuki and Kannan type generalizations of fixed point theorems in generalized cone metric spaces. 展开更多
关键词 fixed point D-metric space 2-metric space generalized cone metric space Kannan mapping generalized Kannan mapping contractive mapping
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Altmetrics与传统科研评价方法对比研究 被引量:1
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作者 刘焕成 胡雨薇 李素巧 《评价与管理》 2017年第3期9-12,共4页
随着Altmetrics的诞生和热议,本文从数据来源,计量指标,评价时效三方面对Altmetrics与传统科研评价方法进行了对比分析。发现Altmetric具有数据来源更广泛,评价指标更全面,更高效的优势。同时,分析了Altmetrics在语言选择、数据采集和... 随着Altmetrics的诞生和热议,本文从数据来源,计量指标,评价时效三方面对Altmetrics与传统科研评价方法进行了对比分析。发现Altmetric具有数据来源更广泛,评价指标更全面,更高效的优势。同时,分析了Altmetrics在语言选择、数据采集和有效性、标准统一上存在的问题。得出了Altmetrics在短期内不能取代传统科研评价方法的结论. 展开更多
关键词 Altmetrics 计量指标 引文分析 Altmetrics工具
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