检索结果-南通市图书馆

Regularization of the Inverse Problem for Time Fractional Pseudo-parabolic Equation with Non-local in Time Conditions

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2022年第12期38卷 2199-2219页

作者： nguyen Duc PHUONG Le Dinh LONG anh tuan nguyen Dumitru BALEANU Faculty of Fundamental Science Industrial University of Ho Chi Minh CityVietnam Division of Applied Mathematics Science and Technology Advanced InstituteVanLang UniversityHoChi Minh CityVietnam Faculty of Technology Van Lang UniversityHo Chi Minh CityVietnam Department of Mathematics Cankaya UniversityAnkaraTurkey Lebanese AmericanUniversity BeirutLebanon Institute of Space Sciences Magurele-BucharestRomania

This paper is devoted to identifying an unknown source for a time-fractional diffusion equation in a general bounded ***,we prove the problem is non-well posed and the stability of the source ***,by using the Modified Fractional Landweber method,we present regularization solutions and show the convergence rate between regularization solutions and sought solution are given under a priori and a posteriori choice rules of the regularization parameter,***,we present an illustrative numerical example to test the results of our theory.

关键词： Source problem fractional pseudo-parabolic problem ill-posed problem convergence estimates regularization

Studies on sustainable features of vernacular architecture in different regions across the world:A comprehensive synthesis and evaluation

在线全文

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2019年第4期8卷 535-548页

作者： anh tuan nguyen nguyen Song Ha Truong David Rockwood anh Dung Tran Le Faculty of Architecture the University of Danang-University of Science and TechnologyDa NangViet Nam School of Architecture University of Hawaii at ManoaUSA Laborotoire des Technologies Innovantes(LTI) Universite de Picardie Jules VerneFrance

Due to the increasing pressure brought by recent global environmental problems,building designers are embracing regionalism and the knowledge of traditional structures,arguing that these structures are energy efficient and highly *** observe clear evidence of the increasing interest in vernacular architecture among the research *** study therefore aims to clarify the contents and issues raised in the studies on vernacular architecture and the knowledge and recommendations that can be derived from them.A database of the research is established by collecting many studies from primary *** data is carefully refined and categorized into a table where synthesized information is *** results of this study show an uneven geographic and climatic distribution of the studies;the trend in selecting research objectives and research objects;the choice of research methods with a clear shift towards quantitative research methods,and the generic findings from the database of the *** results can support diverse inquiries about vernacular architecture across the world and be used as a resource or an orientation to support numerous subsequent studies.

关键词： Vernacular architecture Traditional architecture Sustainable feature Research method Building design

Adaptive data fusion framework for modeling of non-uniform aerodynamic data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第7期36卷 316-336页

作者： Vinh PHAM Maxim TYAN tuan anh nguyen Chi-Ho LEE L.V.Thang nguyen Jae-Woo LEE Department of Aerospace Information Engineering Konkuk UniversitySeoul 05029Republic of Korea Konkuk Aerospace Design-Airworthiness Institute Konkuk UniversitySeoul 05029Republic of Korea

Multi-fidelity Data Fusion(MDF)frameworks have emerged as a prominent approach to producing economical but accurate surrogate models for aerodynamic data modeling by integrating data with different fidelity ***,most existing MDF frameworks assume a uniform data structure between sampling data sources;thus,producing an accurate solution at the required level,for cases of non-uniform data structures is *** address this challenge,an Adaptive Multi-fidelity Data Fusion(AMDF)framework is proposed to produce a composite surrogate model which can efficiently model multi-fidelity data featuring non-uniform ***,the design space of the input data with non-uniform data structures is decomposed into subdomains containing simplified ***,different MDF frameworks and a rule-based selection process are adopted to construct multiple local models for the subdomain *** the other hand,the Enhanced Local Fidelity Modeling(ELFM)method is proposed to combine the generated local models into a unique and continuous global ***,the resulting model inherits the features of local models and approximates a complete database for the whole design *** validation of the proposed framework is performed to demonstrate its approximation capabilities in(A)four multi-dimensional analytical problems and(B)a practical engineering case study of constructing an F16C fighter aircraft’s aerodynamic *** comparisons of the generated models using the proposed AMDF framework and conventional MDF approaches using a single global modeling algorithm are performed to reveal the adaptability of the proposed approach for fusing multi-fidelity data featuring non-uniform ***,the results indicated that the proposed framework outperforms the state-of-the-art MDF approach in the cases of non-uniform data.

关键词： Aerodynamic modeling Data fusion Diverse data structure Multi-fidelity data Multi-fidelity surrogate modeling

Piaoac Granites Related W-Sn Mineralization, Northern Vietnam: Evidences from Geochemistry, Zircon Geochronology and Hf Isotopes

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2019年第1期30卷 52-69页

作者： tuan anh nguyen Xiaoyong Yang Hien Vu Thi Lei Liu Insung Lee School of Earth and Space Sciences University of Science and Technology of China Institute of Geological Sciences Vietnam Academy of Science and Technology(VAST) Department of Geology Hanoi University of Mining and Geology School of Earth and Environmental Sciences Seoul National University

Piaoac granites exposed in the Cao Bang region, northern Vietnam, are S-type granite, which are associated with W-Sn-Mo-Be-F mineralization. Zircon U-Pb ages, major and trace elements, mineral chemical and Hf isotopic compositions of the W-Sn-bearing granites from the Piaoac District have been investigated in detail. LA-ICP-MS U-Pb dating of zircon grains from these granites yielded ages of 82.5±2.3 and 82±1.8 Ma, representing an episode of Late Cretaceous magmatic event. These granites are characterized by high peraluminous and have typical S-type geochemical signatures with high SiO_2(72.37 wt.%–73.07 wt.%), high A/CNK values(1.61–1.65) and Al_2O_3(14.4 wt.%–15 wt.%). They are enriched in Rb, U, K, Th, Ta and Pb and display pronounced negative Ba, Sr, Nb, Ti and Eu(Eu/Eu*=0.19–0.24) anomalies. The high degree of fractional crystallization is characterized by low Rb, Sr, Ba and Eu concentrations with high ratios of La/Sm and Eu/Eu*. Zircon grains show εHf(t) values from-9.69 to-0.9 and the corresponding TDM2 range from 1.2 to 1.7 Ga, indicating that these granites could be derived from the Proterozoic basement rocks with minor input from mantle-derived magmas. The calculation of Fe^(3+) and Fe^(2+) of biotites indicates a low oxygen fugacity condition(log fO_2 ranging from 10-17 to 10-18 bars, below MH), which is favorable for the W-Sn mineralization. Tungsten and tin have been enriched in granitic magmas through fractionation, and low oxygen fugacity conditions have promoted the accumulation and transportation of W-Sn in the hydrothermal fluids, leading to deposition of mineral phases. The geochemical data suggest that Piaoac granites formed in an extensional setting related with the Late Cretaceous magmatism occurring large-scale lithospheric extensional in South China Block.

关键词： geochemistry zircon U-Pb age Hf isotope Piaoac granite W-Sn mineralization Northern Vietnam

On the speed of convergence of Picard iterations of backward stochastic differential equations

在线全文

学校读者我要写书评

暂无评论

Probability, Uncertainty and Quantitative Risk 2022年第2期7卷 133-150页

作者： Martin Hutzenthaler Thomas Kruse tuan anh nguyen Faculty of Mathematics University of Duisburg-EssenThea-Leymann-Str.9EssenNordrhein-Westfalen 45127Germany Institute of Mathematics University of GiessenArndtstraβe 2Giessen 35392Germany

It is a well-established fact in the scientific literature that Picard iterations of backward stochastic differential equations with globally Lipschitz continuous nonlinearities converge at least exponentially fast to the *** this paper we prove that this convergence is in fact at least square-root factorially *** show for one example that no higher convergence speed is possible in ***,if the nonlinearity is zindependent,then the convergence is even factorially *** we reveal a phase transition in the speed of convergence of Picard iterations of backward stochastic differential equations.

关键词： Backward stochastic differential equation Picard iteration A priori estimate Semilinear parabolic partial differential equation

Study of vertically ascending flight of a hawkmoth model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2020年第5期36卷 1031-1045,I0002页

作者： anh tuan nguyen Vu Dan Thanh Le The Hung Tran V.N.Due Van Binh Phung Faculty of Aerospace Engineering Le Quy Don Technical UniversityHanoiVietnam Institute of Theoretical and Applied Research.Duy Tan University HanoiVietnam Division of Construction Computation Institute for Computational ScienceTon Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

This paper provides insight into the wing kinematics,the power requirement and the dynamic stability characteristics of a hawkmoth model in vertically ascending *** wing kinematics of the hawkmoth model is obtained based on the minimum required power *** optimization process is conducted using genetic and simplex algorithms that are coupled with an artificial neural network to rapidly predict the aerodynamic force and required *** training data for the neural network are generated from an unsteady vortex-lattice *** to hover,the results in this study show the larger flapping frequency and the smaller rotation amplitude of the hawkmoth wing kinematics in ascending ***,more power is required when the ascending speed *** conducting a dynamic modal analysis based on a cycle-average approach,the certain effect of the ascending speed on the modal structures of the hawkmoth model was observed.

关键词： Hawkmoth Ascending flapping flight-Genetic algorithm Artificial neural network Flight dynamic stability

A Neural-network-based Approach to Study the Energy-optimal Hovering Wing Kinematics of a Bionic Hawkmoth Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2019年第5期16卷 904-915页

作者： anh tuan nguyen Ngoc Doan Tran Thanh Trung Vu Thanh Dong Pham Quoc Tru Vu Jae-Hung Han Faculty of Aerospace Engineering Le Quy Don Technical University236 Hoang Quoc VietVietnam Office of International Cooperation Le Quy Don Technical University236 Hoang Quoc VietVietnam Department ofAerospace Engineerings Korea Advanced Institute of Science and Technology Daejeon 34141Republic ofKorea

This paper presents the application of an artificial neural network to develop an approach to determine and study the energy-optimal wing kinematics of a hovering bionic hawkmoth model.A three-layered artificial neural network is used for the rapid prediction of the unsteady aerodynamic force acting on the wings and the required *** this artificial network is integrated into genetic and simplex algorithms,the running time of the optimization process is reduced *** validity of this new approach is confirmed in a comparison with a conventional method using an aerodynamic model based on an extended unsteady vortex-lattice method for a sinu soidal wing kinematics *** studying the obtained results,it is found that actual hawkmoths do not hover under an energy-optimal ***,by tilting the stroke plane and lowering the wing positions,they can compromise and expend some energy to enhance their maneuverability and the stability of their flight.

关键词： optimal hovering wing kinematics artificial neural network insect flight genetic algorithm unsteady vortex-lattice method bionics

Adaptive Gaussian Noise Image Removal Algorithm Using Filtering-Based Noise Estimation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Measurement Science and Instrumentation 2011年第3期2卷 230-234页

作者： tuan-anh nguyen Hong-son nguyen Min-cheol HONG Dept.of Information and Telecommunication Soongsil University

This paper proposes a spatially denoising algorithm using filtering-based noise estimation for an image corrupted by Gaussian *** proposed algorithm consists of two stages:estimation and elimination of noise *** adaptively deal with variety of the noise amount,a noisy input image is firstly filtered by a lowpass *** deviation of the noise is computed from different images between the noisy input and its filtered *** addition,a modified Gaussian noise removal filter based on the local statistics such as local weighted mean,local weighted activity and local maximum is used to control the degree of noise *** show the effectiveness of the proposed algorithm.

关键词： denoising local statistics Gaussian filtering noise estimation Gaussian noise

Transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第8期38卷 171-193页

作者： Thuy Tran Thi Thu Tu nguyen anh Hue nguyen Thi Hong nguyen Thi School of Mechanical and Automotive Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Technical Fundamental University of Transport TechnologyHanoiViet Nam Faculty of Mechanical Engineering Thuyloi University175 Tay SonDong DaHanoiViet Nam

Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures.

关键词： Blast load Modified first-order shear theory Biological composite structures