检索结果-南通市图书馆

Paper evolution graph: multi-view structural retrieval for academic literature

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Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 187-205页

作者： Dan-ping LIAO yun-tao QIAN College of Computer Science and Technology Zhejiang University

Academic literature retrieval concerns about the selection of papers that are most likely to match a user's information needs. Most of the retrieval systems are limited to list-output models, in which the retrieval results are isolated from each other. In this paper, we aim to uncover the relationships between the retrieval results and propose a method to build structural retrieval results for academic literature, which we call a paper evolution graph(PEG).The PEG describes the evolution of diverse aspects of input queries through several evolution chains of papers. By using the author, citation, and content information, PEGs can uncover various underlying relationships among the papers and present the evolution of articles from multiple viewpoints. Our system supports three types of input queries: keyword query, single-paper query, and two-paper query. The construction of a PEG consists mainly of three steps. First, the papers are soft-clustered into communities via metagraph factorization, during which the topic distribution of each paper is obtained. Second, topically cohesive evolution chains are extracted from the communities that are relevant to the query. Each chain focuses on one aspect of the query. Finally, the extracted chains are combined to generate a PEG, which fully covers all the topics of the query. Experimental results on a real-world dataset demonstrate that the proposed method can construct meaningful PEGs.

关键词： Paper evolution graph Academic literature retrieval Metagraph factorization Topic coherence

Volume of Singular Hyperbolic Sets

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Acta Mathematica Sinica,English Series 2021年第10期37卷 1507-1512页

作者： Dao Fei ZHANG yun tao ZANG Mathematics Institute University of WarwickCoventryCV47ALUK School of Mathematical Sciences East China Normal UniversityShanghai 200062P.R.C

Let X be a C^(1+)vector field on a compact Riemannian manifold M with dimension d≥***Λbe a transitive singular hypebolic set with positive *** show thatΛ=M andΛis a uniformly hyperbolic set without singularities.

关键词： Uniformly hyperbolic singular hyperbolic volume

Risk analysis and maintenance decision making of natural gas pipelines with external corrosion based on Bayesian network

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Petroleum Science 2022年第3期19卷 1250-1261页

作者： yun-tao Li Xiao-Ning He Jian Shuai College of Safety and Ocean Engineering China University of PetroleumBeijingChina

Buried natural gas pipelines are vulnerable to external corrosion because they are encased in a soil environment for a long *** the causes of external corrosion and taking specific maintenance measures is *** this work,a risk analysis and maintenance decision-making model for natural gas pipelines with external corrosion is proposed based on a Bayesian network.A fault tree model is first employed to identify the causes of external *** Bayesian network for risk analysis is determined *** maintenance strategies are then inserted into the Bayesian network to show a reduction of the *** costs of maintenance strategies and the reduced risk after maintenance are combined in an optimization function to build a decision-making *** of the limitations of historical data,some of the parameters in the Bayesian network are obtained from a probabilistic estimation model,which combines expert experience and fuzzy set ***,a case study is carried out to verify the feasibility of the maintenance decision *** indicates that the method proposed in this work can be used to provide effective maintenance schemes for different pipeline external corrosion scenarios and to reduce the possible losses caused by external corrosion.

关键词： Natural gas pipelines External corrosion Risk analysis Maintenance decision making Bayesian network

Speech enhancement with a GSC-like structure employing sparse coding

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第12期15卷 1154-1163页

作者： Li-chun YANG yun-tao QIAN College of Computer Science and Technology Zhejiang University Intelligent Control Research Institute Zhejiang Wanli University

Speech communication is often influenced by various types of interfering signals. To improve the quality of the desired signal, a generalized sidelobe canceller(GSC), which uses a reference signal to estimate the interfering signal, is attracting attention of researchers. However, the interference suppression of GSC is limited since a little residual desired signal leaks into the reference signal. To overcome this problem, we use sparse coding to suppress the residual desired signal while preserving the reference signal. Sparse coding with the learned dictionary is usually used to reconstruct the desired signal. As the training samples of a desired signal for dictionary learning are not observable in the real environment, the reconstructed desired signal may contain a lot of residual interfering signal. In contrast,the training samples of the interfering signal during the absence of the desired signal for interferer dictionary learning can be achieved through voice activity detection(VAD). Since the reference signal of an interfering signal is coherent to the interferer dictionary, it can be well restructured by sparse coding, while the residual desired signal will be removed. The performance of GSC will be improved since the estimate of the interfering signal with the proposed reference signal is more accurate than ever. Simulation and experiments on a real acoustic environment show that our proposed method is effective in suppressing interfering signals.

关键词： Generalized sidelobe canceller Speech enhancement Voice activity detection Dictionary learning Sparse coding

Preference transfer model in collaborative filtering for implicit data

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Frontiers of Information Technology & Electronic Engineering 2016年第6期17卷 489-500页

作者： Bin JU yun-tao QIAN Min-chao YE Institute of Artificial Intelligence College of Computer Science and TechnologyZhejiang UniversityHangzhou 3100Z7China Health Information Center of Zhejiang Province Hangzhou 310006China

Generally, predicting whether an item will be liked or disliked by active users, and how much an item will be liked, is a main task of collaborative filtering systems or recommender systems. Recently, predicting most likely bought items for a target user, which is a subproblem of the rank problem of collaborative filtering, became an important task in collaborative filtering. Traditionally, the prediction uses the user item co-occurrence data based on users' buying behaviors. However, it is challenging to achieve good prediction performance using traditional methods based on single domain information due to the extreme sparsity of the buying matrix. In this paper, we propose a novel method called the preference transfer model for effective cross-domain collaborative filtering. Based on the preference transfer model, a common basis item-factor matrix and different user-factor matrices are *** user-factor matrix can be viewed as user preference in terms of browsing behavior or buying behavior. Then,two factor-user matrices can be used to construct a so-called ‘preference dictionary' that can discover in advance the consistent preference of users, from their browsing behaviors to their buying behaviors. Experimental results demonstrate that the proposed preference transfer model outperforms the other methods on the Alibaba Tmall data set provided by the Alibaba Group.

关键词： Recommender systems Collaborative filtering Preference transfer model Cross domain Implicit data

Study on HOBEM Based on Analytical Panel Integrals Related to Translating-Pulsating Source for Hydrodynamic Responses of Vessels Sailing in Waves

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China Ocean Engineering 2022年第3期36卷 348-362页

作者： YANG yun-tao ZHU Ren-chuan LI Yu-long School of Naval Architecture and Civil Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600China State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea ExplorationSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Technology Centre for Offshore and Marine Singapore(TCOMS)Singapore

A higher-order boundary element method(HOBEM)incorporated with analytical panel integrals related to translat-ing-pulsating source Green’s function is proposed for the hydrodynamic response prediction of ships advancing in *** this method,the 9-node bi-quadratic curvilinear elements employed to discretize the mixed-source/dipole boundary integral equation are mapped into the parametric plane through a coordinate *** in order to ease the numerical instability problem,a novel analytical quadrature is derived to calculate the influence coefficients by changing the integral order and using integration by *** singularity caused by infinite discontinuity is analyzed and eliminated by adopting some mathematical *** the calculations of panel integrals of Green’s function and its x-derivative,the analytical integral method is proved to be always accurate even for field points approaching the free surface,where numerical quadrature is impossible to give reasonable *** on this,a higher-order seakeeping program is developed and applied in the motion response prediction of two different types of ships(i.e.,a wall-sided ship Wigley III and a non-wall-sided ship S175).By comparing the computed results with the corresponding experimental data and numerical solutions of the translating-pulsating and higher-order Green’s function methods based on traditional Gauss quadrature,it is found that the HOBEM based on analytical quadrature is of better accuracy and *** the non-wall-sided ship,only the present method can produce reasonable pre-diction of motion responses,while obvious oscillatory phenomenon is observed in the results of the other two numerical methods based on Gauss quadrature.

关键词： HOBEM translating-pulsating Green’s function analytical quadrature seakeeping forward speed

One-pot Three-component Mannich Reaction Catalyzed by 2-Hydroxylpyridine

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Chemical Research in Chinese Universities 2013年第4期29卷 710-713页

作者： JIN Li-li LEI yun-tao College of Sciences China Pharmaceutical University Nanjing 210009 P. R. China

An effcient synthetic protocol for the β-amino carbonyl compounds was developed via one-pot three- component Mannich reaction of aromatic aldehydes, aromatic amines and cyclohexanone catalyzed by 2-hydroxylpy- ridine under mild reaction conditions, β-Amino carbonyl compounds were obtained in moderate to good yields and rea- sonable diastereoselectivities. The effects of different solvents, catalyst amounts and the scope of different substrates on the Mannich reactions were investigated. The plausible reaction mechanism was also discussed.

关键词： 2-Hydroxylpyridine Catalyze Mannich reaction fl-Amino carbonyl compound

Numerical Study on Motion Responses of Two Parallel Ships During Underway Replenishment by the Semi-Analytical HOTP Method

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China Ocean Engineering 2022年第2期36卷 233-246页

作者： YANG yun-tao ZHU Ren-chuan MA Chao GAO Hui School of Naval Architecture and Civil Engineering Jiangsu University of Science and TechnologyZhangjiagang 215600China State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea ExplorationSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of High Performance Ship Technology(Wuhan University of Technology) Ministry of EducationWuhan 430063China School of Naval Architecture Ocean and Energy Power EngineeringWuhan University of TechnologyWuhan 430063China

Motion responses of two ships advancing parallel in waves with hydrodynamic interactions are investigated in this paper. Within the framework of the frequency-domain potential flow theory, a semi-analytical higher-order translating-pulsating source(HOTP) method is presented to solve the problems of coupled radiation and diffraction potential. The method employs nine-node bi-quadratic curvilinear elements to discretize the boundary integral equations(BIEs) constructed over the mean wetted surface of the two ship hulls. In order to eliminate the numerical oscillation, analytical quadrature formulas are derived and adopted to evaluate the integrals related to the Froudedependent part of the Green’s function along the horizontal direction in the BIEs. Based on the method, a numerical program is originally coded. Through the calculations of hydrodynamic responses of single ships, the numerical implementation is proved successful. Then the validated program is applied in the investigations on the hydrodynamic interactions of two identical Wigley Ⅲ hulls and the underway replenishment of a frigate and a supply ship in waves with and without stagger, respectively. The comparison between the present computed results with experimental data and numerical solutions of other methods shows that the semi-analytical HOTP method is of higher accuracy than the pulsating source Green’s function method with speed correction and better stability than the traditional HOTP method based on Gauss quadrature. In addition, for two ships with obviously different dimensions,the influence of hydrodynamic interactions on the smaller ship is found to be more noticeable than that on the larger ship, which leads to the differences between the motions of frigate with and without the presence of supply ship.

关键词： semi-analytical HOTP method two parallel ships underway replenishment coupled motions

Application of ultrasound contrast in identification and diagnosis of ocular spaceoccupying lesions

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International Journal of Ophthalmology(English edition) 2011年第4期4卷 337-342页

作者： Jia-Ying Yuan, yun-tao Zhang Department of Ultrasonography Hospital of Military Area of He'nan Zhengzhou 450003 He'nan Province China The Faculty of Biomedical Engineering of Zhengzhou University Zhengzhou 450001 He'nan Province China Department of Ultrasonography Xi'an Electricity Hospital Xi'an 710032 Shaanxi Province China Department of Urology Surgery Xijing Hospital the Fourth Military Medical University Xìan 710032 Shaanxi Province China

AIM: To analyze the application significance of ultrasound contrast agent in identification and diagnosis of ocular spaceoccupying lesions, and mainly analyze its advantages and problems. METHODS: Thirty-two representative literatures about the application of ultrasound contrast agent in diagnosis of spaceoccupying lesions at home and abroad were collected after focused on sorting the literature reporting the application of ultrasound contrast diagnostic technology in the diagnosis and identification of ocular spaceoccupying lesions in recent years. Its advantages and problems were retrospectively analyzed, and reasonable assessment on Existing problems was made and possible solutions to the problems were proposed. RESULTS: As a new imaging diagnostic technique, the contrast-enhanced ultrasound, which can enhance the display of tumor microcirculation vessels and improve the tumor's ultrasound diagnostic capability, was analyzed. Through sorting and comprehensively analyzing the collected literatures, the positive rate of ocular spaceoccupying lesion diagnosis could be significantly improved with ultrasound contrast technology. Thus, the vascular perfusion in normal tissues and lesions was reflected objectively. According to the lesion's perfusion characteristics of the contrast agent plus with the performance features of two-dimensional ultrasound, the ocular spaceoccupying lesions can be accurately diagnosed, and this could provide clinicians with reliable research basis in this field. CONCLUSION: Ultrasound contrast examination is a new testing method, and ultrasound contrast agent can significantly enhance the ultrasonic detection signal, clearly show the blood perfusion in vessels and tissues, increase the image contrast resolution, and improve the lesion's detection capability in the microcirculation perfusion level, especially its important value in the diagnosis of ocular tumor.

关键词： ultrasound contrast ocular spaceoccupying lesion differential diagnosis new microbubble contrast agent