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Optimal control of quadratic functionals for affine nonlinear systems

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Theoretical & Applied mechanics Letters 2012年第4期2卷 56-59页

作者： m.popescu A.Dumitrache Institute of mathematical Statistics and Applied mathematics Calea 13 Septembrie 13Bucharest 050711Romania

In this paper we analyze the optimal control problem for a class of afflne nonlinear systems under the assumption that the associated Lie algebra is nilpotent. The Lie brackets generated by the vector fields which define the nonlinear system represent a remarkable mathematical instrument for the control of affine systems. We determine the optimal control which corresponds to the nilpotent operator of the first order. In particular, we obtain the control that minimizes the energy of the given nonlinear system. Applications of this control to bilinear systems with first order nilpotent operator are considered.

关键词： optimal control affine nonlinear systems nilpotent operator quadratic functionals

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Existence and Uniqueness of the Optimal Control in Hilbert Spaces for a Class of Linear Systems

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Intelligent Information management 2010年第2期2卷 134-142页

作者： m. popescu 不详

We analyze the existence and uniqueness of the optimal control for a class of exactly controllable linear systems. We are interested in the minimization of time, energy and final manifold in transfer problems. The state variables space X and, respectively, the control variables space U, are considered to be Hilbert spaces. The linear operator T(t) which defines the solution of the linear control system is a strong semigroup. Our analysis is based on some results from the theory of linear operators and functional analysis. The results obtained in this paper are based on the properties of linear operators and on some theorems from functional analysis.

关键词： Existence and Uniqueness Optimal Control Controllable Linear Systems Linear Operator

Is it better to use two elastographic methods for liver fibrosis assessment?

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World Journal of Gastroenterology 2011年第33期17卷 3824-3829页

作者： Ioan Sporea Roxana Sirli Alina popescu Simona Bota Radu Badea monica Lupsor mircea Focsa mirela Danila Department of Gastroenterology and Hepatology University of Medicine and Pharmacy Timisoara10 Iosif Bulbuca Bv.300736 TimisoaraRomania Department of medical Imaging 3rd Medical ClinicUniversity of Medicine and PharmacyClujNapoca2123 Croitorilor str.400162 ClujNapocaRomania Department of Biophysics and medical Informatics University of Medicine and Pharmacy Timisoara14 Tudor Vladimirescu str.300173 TimisoaraRomania

AIm:To find out if by combining 2 ultrasound based elastographic methods:acoustic radiation force impulse(ARFI)elastography and transient elastography(TE),we can improve the prediction of fibrosis in patients with chronic hepatitis ***:Our study included 197 patients with chronic hepatitis *** each patient,we performed,in the same session,liver stiffness(LS)measurements by means of TE and ARFI,respectively,and liver biopsy(LB),assessed according to the metavir score.10 LS measurements were performed both by TE and ARFI;median values were calculated and expressed in kilopascals(kPa)and meters/second(m/s),*** TE and ARFI measurements with IQRmeasurements and fibrosis(r=0.741),between ARFI and fibrosis(r=0.730)and also between TE and ARFI(r=0.675).For predicting significant fibrosis(F≥2),for a cutoff of 6.7 kPa,TE had 77.5% sensitivity(Se)and 86.5%specificity(Sp)[area under the receiver operating characteristic curve(AUROC)0.87] and for a cutoff of 1.2 m/s,ARFI had 76.9%Se and 86.7%Sp(AUROC 0.84).For predicting cirrhosis(F=4),for a cutoff of 12.2 kPa,TE had 96.2%Se and 89.6% Sp(AUROC 0.97)and for a cutoff of 1.8 m/s,ARFI had 90.4%Se and 85.6%Sp(AUROC 0.91).When both elastographic methods were taken into consideration,for predicting significant fibrosis(F≥2),(TE≥6.7 kPa and ARFI≥1.2 m/s)we obtained 60.5%Se,93.3% Sp,96.8%positive predictive value(PPV),41.4%negative predictive value(NPV)and 68%accuracy,while for predicting cirrhosis(TE≥12.2 kPa and ARFI≥1.8 m/s) we obtained 84.9%Se,94.4%Sp,84.9%PPV,94.4% NPV and 91.8%***:TE used in combination with ARFI is highly specific for predicting significant fibrosis;therefore when the two methods are concordant,liver biopsy can be avoided.

关键词： Transient elastography Acoustic radiation force impulse elastography Liver stiffness Combined methods

Assessment of Air Pollution,by the Urban Traffic,in University Campus of Bucharest

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Journal of Environmental Protection 2017年第8期8卷 884-897页

作者： Razvan Stefan popescu Lelia Letitia popescu Technical University of Civil Engineering of Bucharest BucharestRomania

This study aims to measure traffic-related air pollution of vehicles with internal combustion, the main source of emissions of BTEX, organic compounds and NOx, NO2, NO, O3, CO, SO2, Pm10 and Pm2.5, inorganic compounds, in three sites of the University campus, surrounded by residential areas. According to the University data, around 8000 students are being exposed daily to the measured level of pollution, in all 3 studied places of campus. A mobile laboratory was used, which continuously measures above mentioned pollutants and mete-orological parameters. The diurnal variation of BTEX, in a sunny and rainy day showed two peaks of BTEX concentration in the morning and evening. In the rainy days, the non-polar (hydrophobic) compounds as BTEX are mechanically trained by rain into the ground, where either they enter into the groundwater, or volatilized and re-enter in the air. Particulate matter such as Pm10 and Pm2.5 is, in a large part, carried by the rain into the soil. The polar compounds (hydrophilic, NOx, SO2) dissolves in the rainwater and are absorbed in the soil (increasing soil acidity) and evaporated towards the clouds (leading to acid rain). In our study, BTEX compounds removed by the rain varied between 62% - 75%, NOx and SO2, 80% and 77% respectively. Particulate matters were washed out up to 68% for Pm10, and 42% for Pm2.5. In the sunny days the air pollution with measured concentrations of O3 (121.66 ± 7.02, 123.56 ± 4.89 μg/m3) remained for 7 hours close to the limit value (120 μg/m3). The maximum of solar radiation, with corresponding low concentrations in NOx and xylene, corresponds to photochemical reactions in the atmosphere, generating photochemical smog. In a sunny day and high traffic, we found the maximum value 5.4 μg/m3 for benzene, for 30 min., a known human carcinogen, exceeding the annual limit value de 5 μg/m3. The average background, from benzene, in three University campuses daily visited by around 8000 students was 0.97 μg/m3, exposed to 1

关键词： University Campus Outdoor Air Quality BTEX mobile Laboratory Pm10 Pm2.5

GANscan:continuous scanning microscopy using deep learning deblurring

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Light(Science & Applications) 2022年第10期11卷 2378-2387页

作者： michael John Fanous Gabriel popescu Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA Department of Bioengineering University of Illinois at Urbana-Champaign306 N.Wright StreetUrbanaIL 61801USA Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign306 N.Wright StreetUrbanaIL 61801USA

most whole slide imaging(WSI)systems today rely on the"stop-and-stare"approach,where,at each field of view,the scanning stage is brought to a complete stop before the camera snaps a *** procedure ensures that each image is free of motion blur,which comes at the expense of long acquisition *** order to speed up the acquisition process,especially for large scanning areas,such as pathology slides,we developed an acquisition method in which the data is acquired continuously while the stage is moving at high *** generative adversarial networks(GANs),we demonstrate this ultra-fast imaging approach,referred to as GANscan,which restores sharp images from motion blurred *** allows us to complete image acquisitions at 30x the throughput of stop-and-stare *** method is implemented on a Zeiss Axio Observer Z1 microscope,requires no specialized hardware,and accomplishes successful reconstructions at stage speeds of up to 5000 μm/*** validate the proposed method by imaging H&E stained tissue *** method not only retrieves crisp images from fast,continuous scans,but also adjusts for defocusing that occurs during scanning within+/-5 μ*** a consumer GPU,the inference runs atms/image.

关键词： hardware continuous image

Advancements in Fixed Point Theorems for α-Geraghty Contractions in Complete metric Space

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Journal of mathematical Research with Applications 2024年第5期 697-710页

作者： V.C.BORKAR mohammed m.A.TALEB Saeed A.A.AL-SALEHI School of mathematical at Yeshwant mahavidyalaya Swami Ramanand Teerth Marathwada University School of mathematical at Science College Swami Ramanand Teerth Marathwada University Department of mathematics Hodeidah University Department of mathematics Aden University

This article improves and advances the results achieved by Vishal and Naveen, leveraging the use of Lebesgue integrable functions. Going beyond, we investigate fixed point theorems associated with a concept introduced by Ovidiu popescu. Our research not only bolsters the theoretical framework but also unveils practical applications in the domain of Lebesgue integrals as in Example 3.6. Furthermore, our contribution enhances the understanding of fixed point theorems in metric spaces and introduces novel perspectives in the study of generalized α-Geraghty contractive mappings on Lebesgue integrals.

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High-resolution impedance mapping using electrically activated quantitative phase imaging

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Light(Science & Applications) 2021年第2期10卷 186-196页

作者： Cristina Polonschii mihaela Gheorghiu Sorin David Szilveszter Gáspár Sorin melinte Hassaan majeed mikhail E.Kandel Gabriel popescu Eugen Gheorghiu International Centre of Biodynamics 060101 BucharestRomania Institute of Information and Communication Technologies Electronics and Applied MathematicsUniversite Catholique de Louvain1348 Louvain-la-NeuveBelgium Quantitative Light Imaging Laboratory Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana-ChampaignUrbanaIL 61801USA

Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need,likely to impact various applications from biomedicine to energy *** this study,we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation,high spatial resolution,and low temporal *** achieve this,we advance a quantitative phase imaging system,referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation,to provide complementary maps of the optical path and electrical *** demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized,semi-transparent,structured coatings involving two materials with relatively similar electrical *** map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as~550 nm in a titanium(dioxide)over-layer deposited on a glass *** show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution-and beyond the limitations of electrode-based technologies(surface or scanning technologies).The findings,which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal *** virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.

关键词： impedance resolution phase

Evaluation of soil erosion risk and identification of soil cover and management factor (C) for RUSLE in European vineyards with different soil management

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International Soil and Water Conservation Research 2020年第4期8卷 337-353页

作者： m.Biddoccu G.Guzmán G.Capello T.Thielke P.Strauss S.Winter J.G.Zaller A.Nicolai D.Cluzeau D.popescu C.Bunea A.Hoble E.Cavallo J.A.Gómez Institute for Agricultural and Earthmoving machines(ImAmOTER) National Research Council of Italy(CNR)TorinoItaly Institute for Sustainable Agriculture CSICCordobaSpain Institute for Land and Water management Research Federal Agency for Water ManagementPetzenkirchenAustria Institute of Plant Protection and Institute of Integrative Nature Conservation Research University of Natural Resources and Life SciencesViennaAustria Institute of Zoology University of Natural Resources and Life Sciences ViennaViennaAustria UniversitéRennes 1 Station Biologique de PaimpontUMR 6553 EcoBio35380PaimpontFrance SC JIDVEI SRI Research DepartmentJidveiRomania University of Agriculture Science and Veterinary medicine Cluj NapocaRomania

Vineyards show some of the largest erosion rates reported in agricultural areas in *** rates vary considerably under the same land use,since erosion processes are highly affected by climate,soil,topography and by the adopted soil management *** also shows differences in the effect of same conservation practices on reducing soil erosion from conventional,bare soil based,*** Revised Universal Soil Loss Equation(RUSLE)is commonly adopted to estimate rates of water erosion on cropland under different forms of land use and management,but it requires proper value of soil cover and management(C)factors in order to obtain a reliable evaluation of local soil erosion *** this study the ORUSCAL(Orchard RUSle CALibration)is used to identify the best calibration strategy against long-term experimental ***,ORUSCAL is used in order to apply the RUSLE technology from farm based information across different European wine-growing *** results suggest that the best strategy for calibration should incorporate the soil moisture sub-factor(Sm)to provide better soil loss *** C factor,whose average values ranged from 0.012 to *** a large spatial variability due to coupling with local climate and specific local *** comparison across the five wine-growing regions indicates that for the soil protection management,permanent cover crop is the best measure for accomplishing sustainable erosion rates across the studied *** and temporary cover crops,that are used in areas of limited water resources to prevent competition with vines,failed to achieve sustainable erosion rates,that still need to be *** raises the need for a careful use of C values developed under different environmental conditions.

关键词： Vineyard Erosion Soil management RUSLE Europe

mid-mantle water transportation implied by the electrical and seismic properties ofε-FeOOH

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Science Bulletin 2022年第7期67卷 748-754页

作者： Yukai Zhuang Bo Gan Zhongxun Cui Ruilian Tang Renbiao Tao mingqiang Hou Gang Jiang Catalin popescu Gaston Garbarino Youjun Zhang Qingyang Hu Center for High Pressure Science and Technology Advanced Research Beijing 100094China Institute of Atomic and molecular Physics Sichuan UniversityChengdu 610065China School of materials Science and Engineering Changchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China Consorcio para la Construcción Equipamiento y Explotación del Laboratorio de Luz de SincrotrónCerdanyola del VallèsBarcelona 08290Spain European Synchrotron Radiation Facility Grenoble 38000France International Center for Planetary Science College of Earth SciencesChengdu University of TechnologyChengdu 610059China Center for Excellence in Deep Earth Science Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

Water in the mantle transition zone and the core-mantle boundary plays a key role in Earth’s stratification,volatile cycling,and core *** water transportation is actively running between the aforementioned layers,the lower mantle should contain water channels with distinctive seismic and/or electromagnetic ***,we investigated the electrical conductivity and sound velocity ofε-FeOOH up to 71 GPa and 1800 K and compared them with global tomography *** abrupt threeorder jump of electrical conductivity was observed above 50 GPa,reaching 1.24(12)×10^(3)S/m at 61 ***,the longitudinal sound velocity dropped by 16.8%in response to the high-to-low spin transition of Fe^(3+).The high-conductivity and low-sound velocity ofε-FeOOH match the features of heterogenous scatterers in the mid-lower *** unique properties of hydrousε-FeOOH,or possibly other Fe-enriched phases can be detected as evidence of active water transportation in the mid-lower mantle.

关键词： mid-lower mantle Electrical conductivity Seismic velocity Heterogeneity

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