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Modeling of hydrological processes in arid agricultural regions

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frontiers of Agricultural Science and Engineering 2015年第4期2卷 283-294页

作者： Jiang LI Xiaomin MAO Shaozhong KANG david ABARRY College of Water Resources and Civil Engineering China Agricultural UniversityBeijing 100083China Laboratoire de technologieécologique Institut d’ingénierie de l’environnementStation 2Ecole polytechnique fédérale de Lausanne(EPFL)CH-1015 LausanneSwitzerland

Understanding of hydrological processes,including consideration of interactions between vegetation growth and water transfer in the root zone,underpins efficient use of water resources in arid-zone *** transfers take place in the soil-plant-atmosphere continuum,and include groundwater dynamics,unsaturated zone flow,evaporation/transpiration from vegetated/bare soil and surface water,agricultural canal/surface water flow and seepage,and well *** can be categorized into three classes:(1)regional distributed hydrological models with various land uses,(2)groundwater-soil-plant-atmosphere continuum models that neglect lateral water fluxes,and(3)coupled models with groundwater flow and unsaturated zone water *** review highlights,in addition,future research challenges in modeling arid-zone agricultural systems,e.g.,to effectively assimilate data from remote sensing,and to fully reflect climate change effects at various model scales.

关键词： hydrological processes irrigation area SPAC crop growth groundwater canal seepage

Cryptanalysis of the double-Moduli Cryptosystem

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International Journal of Communications, Network and System Sciences 2012年第12期5卷 834-838页

作者： Sonia Mihaela Bogos Serge Vaudenay école polytechnique fédérale de lausanne (epfl) Lausanne Switzerland

In this article we present a lattice attack done on a NTRU-like scheme introduced by Verkhovsky in [1]. We show how, based on the relation between the public and private key, we can construct an attack which allows any passive adversary to decrypt the encrypted messages. We explain, step by step, how an attacker can construct an equivalent private key and guess what the original plaintext was. Our attack is efficient and provides good experimental results.

关键词： Complex Modulus Primary Residue Plaintext Pre-Conditioning Plaintext Attack Public-Key Scheme Lattices LLL Algorithm Orthogonal Lattices

A PARALLEL ALGORITHM fOR THE SOLUTION Of LARGE-SCALE NONCONfORMING fLUId-STRUCTURE INTERACTION PROBLEMS IN HEMOdYNAMICS

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Journal of Computational Mathematics 2017年第3期35卷 363-380页

作者： davide forti Alfio Ouarteroni Simone dedaris MATH-CMCS Ecole Polytechnique Federale de Lausanne Station 8 CH-1015 Lausanne Switzerland

In this work we address the numerical solution of large scale fluid-structure interaction problems when nonconforming grids and/or nonconforming finite elements discretizations are used at the interface separating the fluid and structure physical domains. To deal with nonconforming fluid-structure discretizations we use the INTERNOdeS method （INTER- polation for NOnconforming decompositionS） formerly introduced in [6] for the solution of elliptic Pdes on nonconforming domain decomposition. To cope with the high com- putational complexity of the three dimensional fSI problem obtained after spatial and temporal discretization, we use the block parallel preconditioner faCSI [7]. A numerical investigation of the accuracy properties of INTERNOdeS applied to the nonconforming fSI problem is carried out for the simulation of the pressure wave propagation in a straight elastic cylinder. finally, we study the scalability performance of the faCSI precondition- er in the nonconforming case by solving a large-scale nonconforming fSI problem in a patient-specific arterial bypass.

关键词： fluid-Structure Interaction domain decomposition Nonconforming discretizations INTERNOdeS Biomechanics Parallel preconditioners High performance comput-ing.

Open channel-based microchip electrophoresis interfaced with mass spectrometry via electrostatic spray ionization

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Chinese Chemical Letters 2016年第1期27卷 85-87页

作者： Yan deng Liang Qiao Natalia Gasilova Xin-Xiang Zhang Hubert H.Girault Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of Chemistry Peking University Laboratoire d’Electrochimie Physique et Analytique Ecole Polytechnique Fédérale de Lausanne

The coupling between open channel-based microchip electrophoresis and mass spectrometry via electrostatic spray ionization is proposed for in situ detection of fractionated analytes. Electrophoretic separation is performed in an open channel fabricated in a plastic substrate. The solvent of background electrolyte is evaporated from the open channel because of Joule heating during electrophoresis, leaving the dried electrophoretic bands to be directly analyzed by mass spectrometry via scanning electrostatic spray ionization. Proof-of-concept results are obtained with fluorescent dyes and antibiotics as the test samples, demonstrating an efficient on-chip detection platform based on the electrophoresis and electrostatic spray ionization mass spectrometry.

关键词： Open channel Microchip electrophoresis Interface Electrostatic spray ionization mass spectrometry

Micro 3d printing of a functional MEMS accelerometer

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Microsystems & Nanoengineering 2022年第5期8卷 69-79页

作者： Simone Pagliano david E.Marschner damien Maillard Nils Ehrmann Göran Stemme Stefan Braun Luis Guillermo Villanueva frank Niklaus KTH Royal Institute of Technology Division of Micro and NanosystemsMalvinas väg 10StockholmSweden École polytechnique fédérale de lausanne(epfl) Advanced NEMS LaboratoryInstitute of Mechanical Engineering1015 LausanneSwitzerland Hochschule Kaiserslautern University of Applied SciencesInformatik und MikrosystemtechnikCampus ZweibrückenGermany

Microelectromechanical system(MEMS)devices,such as accelerometers,are widely used across industries,including the automotive,consumer electronics,and medical *** are efficiently produced at very high volumes using large-scale semiconductor manufacturing ***,these techniques are not viable for the costefficient manufacturing of specialized MEMS devices at low-and medium-scale ***,applications that require custom-designed MEMS devices for markets with low-and medium-scale volumes of below 5000–10,000 components per year are extremely difficult to address *** 3d printing of MEMS devices could enable the efficient realization and production of MEMS devices at these low-and medium-scale ***,current micro-3d printing technologies have limited capabilities for printing functional ***,we demonstrate a functional 3d-printed MEMS accelerometer using 3d printing by two-photon polymerization in combination with the deposition of a strain gauge transducer by metal *** characterized the responsivity,resonance frequency,and stability over time of the MEMS *** results demonstrate that the 3d printing of functional MEMS is a viable approach that could enable the efficient realization of a variety of custom-designed MEMS devices,addressing new application areas that are difficult or impossible to address using conventional MEMS manufacturing.

关键词： printing accelerometer functional

Ultra-thin Bloch-surface-wave-based reflector at telecommunication wavelength

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Photonics Research 2017年第5期5卷 494-499页

作者： R. dUBEY B. VOSOUGHI LAHIJANI M. HAYRINEN M. ROUSSEY M. KUITTINEN H. P. HERZIG Optics & Photonics Technology Laboratory (OPT) ecole Polytechnique Federale de Lausanne (EPFL) rue de la Maladiere 71b Institute of Photonics University of Eastern Finland

We experimentally demonstrate the optical properties of gratings engraved in a single-mode waveguide fabricated on top of a dielectric multilayer platform. The structure can be approached as a reflector for Bloch-surface-wavebased two-dimensional optical systems. The gratings have been fabricated on a thin(～λ∕25) titanium dioxide layer with a thickness of a few tens of nanometers deposited on the top of a multilayer platform. The optical properties of the gratings have been characterized in the near field with the aid of multi-heterodyne scanning nearfield optical microscopy. We investigate the surface wave's interference pattern, produced by incident and reflected light in front of the gratings. The presented gratings behave as an efficient Bloch-surface–wave-basedreflector at telecommunication wavelength.

关键词： reflector Bloch waveguide multilayer behave grating Bragg dielectric titanium fabrication

Misalignment Between Skills discovered, disseminated, and deployed in the Knowledge Economy

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Journal of Social Computing 2022年第3期3卷 191-205页

作者： Bhargav Srinivasa desikan James Evans the department of Computer and Communication Sciences École Polytechnique Fédérale de Lausanne(EPFL)Lausanne 1015Switzerland the Knowledge Lab the Department of SociologyUniversity of ChicagoChicagoIL 60615USAand also with the Santa Fe InstituteSanta FeNM 87501USA

The knowledge economy is a complex and dynamical system,where knowledge and skills are discovered through research,diffused via education,and deployed by *** aligning the supply of new knowledge with the demand for practical skills through education is critical for developing national innovation systems that maximize human *** this paper,we evaluate the complex alignment of skills across the knowledge economy by creating an integrated semantic model that neurally encodes invented,instructed,and instituted skills across three major datasets:research abstracts from the Web of Science,teaching syllabi from the Open Syllabus Project,and job advertisements from Burning *** the high dimensional knowledge and skills space inscribed by these data,we draw critical insight about systemic misalignment between the diversity of skills supplied and demanded in the knowledge *** with insights from economic geography,demand for skills from industry exhibits high entropy(diversity)at local,regional,and national levels,demonstrating dense complementarities between them at all levels of the *** with the economics and sociology of innovation,we find low entropy in the invention of new knowledge and skills through research,as specialist researchers cluster within *** provide new evidence,however,for the low entropy of skills taught at local,regional,and national levels,illustrating a massive mismatch between diversity in skills supplied versus *** misalignment is sustained by the spatial and institutional mismatch in the organization of education by researchers at the site of skill invention over *** findings suggestively trace the societal costs of tethering education to researchers with narrow knowledge rather than students with broad skill needs.

关键词： computational content analysis knowledge economy sociology of knowledge natural language processing data science and society

A Local discontinuous Galerkin Method for Two-dimensional Time fractional diffusion Equations

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Communications on Applied Mathematics and Computation 2020年第4期2卷 689-709页

作者： Somayeh Yeganeh Reza Mokhtari Jan SHesthaven department of Mathematical Sciences Isfahan University of TechnologyIsfahan 84156-83111Iran epfl-SB-MATHICES-MCSS École Polytechnique Fédéral de Lausanne1015 LausanneSwitzerland

for two-dimensional(2d)time fractional diffusion equations,we construct a numerical method based on a local discontinuous Galerkin(LdG)method in space and a finite differ-ence scheme in *** investigate the numerical stability and convergence of the method for both rectangular and triangular meshes and show that the method is unconditionally *** results indicate the effectiveness and accuracy of the method and con-firm the analysis.

关键词： Two-dimensional(2d)time fractional difusion equation Local discontinuous Galerkin method(LdG) Numerical stability Convergence analysis

Stability Study on Hydroelectric Production Site Using Eigenvalues Analysis Method

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Journal of Energy and Power Engineering 2012年第6期6卷 940-948页

作者： Pedro Camilo de Oliveira e Silva Basile Kawkabani Sébastien Alligné Christophe Nicolet Jean-Jacques Simond francois Avellan Electrical Machinery Laboratory Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne CH-1015 Switzerland Laboratory for Hydraulic Machines Ecole Polytechnique Fédérale de Lausanne EPFL Lausanne CH-1015 Switzerland Power Vision Engineering Sàrl Eeublens CH-1024 Switzerland

The eigenvalues analysis method is generally applied to synchronous machines by using d, q-components. This paper presents the application of this method on an equivalent model for the synchronous machine based on phase variables a, b, c instead of d, q-components. The advantages of this approach, essential for programs using phase variables as state variables, are presented. The application of this method to a complete hydroelectric production site including hydraulic components （pump-turbine, penstock, gallery, reservoir...） permits the study and analysis of the interactions between the hydraulic, electric and regulation parts of the system. Results coming from the proposed eigenvalues analysis method and the numerical simulations confirm the interest of the presented approach.

关键词： Hydraulic systems eigenvalues and eigenfunctions power systems transient analysis.