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Topology-preserving flocking of nonlinear agents using optimistic planning

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Control Theory and Technology 2015年第1期13卷 70-81页

作者： Lucian BU?ONiU irinel-constantin MORRESCU Department of Automation Technical University of Cluj-NapocaMemorandumului 28 400114 Cluj-Napoca Romania Université de Lorraine CRAN UMR 7039 and CNRS CRAN UMR 7039 2 Avenue de la Forêt de HayeVandoeuvre-lès-Nancy France

We consider the generalized flocking problem in multiagent systems, where the agents must drive a subset of their state variables to common values, while communication is constrained by a proximity relationship in terms of another subset of variables. We build a flocking method for general nonlinear agent dynamics, by using at each agent a near-optimal control technique from artificial intelligence called optimistic planning. By defining the rewards to be optimized in a well-chosen way, the preservation of the interconnection topology is guaranteed, under a controllability assumption. We also give a practical variant of the algorithm that does not require to know the details of this assumption, and show that it works well in experiments on nonlinear agents.

关键词： Multiagent systems flocking optimistic planning topology preservation

AS-index： A Structure for String Search Using n-Grams and Algebraic Signatures

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Journal of Computer Science & Technology 2016年第1期31卷 147-166页

作者： Camelia constantin Cedric du Mouza Witold Litwin Philippe Rigaux Thomas Schwarz LiP6 Laboratory University Pierre et Marie Curie Paris 75005 France CEDRiC Laboratory Conservatoire National des Arts et Metiers Paris 75003 France LAMSADE Laboratory University Paris-Dauphine Paris 75775 France DiCC Laboratory Universidad Catolica del Uruguay Montevideo 11200 Uruguay

We present the AS-index, a new index structure for exact string search in disk resident databases. AS-index relies on a classical inverted file structure, whose main innovation is a probabilistic search based on the properties of algebraic signatures used for both n-grams hashing and pattern search. Specifically, the properties of our signatures allow to carry out a search by inspecting only two of the posting lists. The algorithm thus enjoys the unique feature of requiring a constant number of disk accesses, independently from both the pattern size and the database size. We conduct extensive experiments on large datasets to evaluate our index behavior. They confirm that it steadily provides a search performance proportional to the two disk accesses necessary to obtain the posting lists. This makes our structure a choice of interest for the class of applications that require very fast lookups in large textual databases. We describe the index structure, our use of algebraic signatures, and the search algorithm. We discuss the operational trade-offs based on the parameters that affect the behavior of our structure, and present the theoretical and experimental performance analysis. We next compare the AS-index with the state-of-the-art alternatives and show that 1） its construction time matches that of its competitors, due to the similarity of structures, 2） as for search time, it constantly outperforms the standard approach, thanks to the economical access to data complemented by signature calculations, which is at the core of our search method.

关键词： full text indexing large-scale indexing algebraic signature

Real-time hybrid simulation of structures equipped with viscoelastic-plastic dampers using a user-programmable computational platform

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 693-711页

作者： Jack Wen Wei Guo Ali Ashasi-Sorkhabi Oya Mercan constantin Christopoulos Kinetica 1235 Bay St.Suite 1004ONM5R 3K4 Department of Civil Engineering University of Waterloo200 University Avenue WWaterlooONN2L 3G1Canada Department of Civil Engineering University of Toronto35 St.George StreetTorontoONM5S 1A4Canada

A user-programmable computational/control platform was developed at the University of Toronto that offers real-time hybrid simulation （RTHS） capabilities. The platform was verified previously using several linear physical substructures. The study presented in this paper is focused on further validating the RTHS platform using a nonlinear viscoelastic-plastic damper that has displacement, frequency and temperature-dependent properties. The validation study includes damper component characterization tests, as well as RTHS of a series of single-degree-of-freedom （SDOF） systems equipped with viscoelastic-plastic dampers that represent different structural designs. From the component characterization tests, it was found that for a wide range of excitation frequencies and friction slip loads, the tracking errors are comparable to the errors in RTHS of linear spring systems. The hybrid SDOF results are compared to an independently validated thermal- mechanical viscoelastic model to further validate the ability for the platform to test nonlinear systems. After the validation, as an application study, nonlinear SDOF hybrid tests were used to develop performance spectra to predict the response of structures equipped with damping systems that are more challenging to model analytically. The use of the experimental performance spectra is illustrated by comparing the predicted response to the hybrid test response of 2DOF systems equipped with viscoelastic-plastic dampers.

关键词： real-time hybrid simulation user-programmable computational/control platform supplemental dampers performance spectra

Abscesses of the spleen:Report of three cases

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World Journal of Gastroenterology 2008年第19期14卷 3088-3091页

作者： constantin Fotiadis Giagkos Lavranos Pavlos Patapis Gabriel Karatzas 3rd Department of Surgery Attikon University Hospital

Abscess of the spleen is a rare discovery, with about 600 cases in the international literature so far. Although it may have various causes, it is most usually associated with trauma and infections of the spleen. The latter are more common in the presence of a different primary site of infection, especially endocarditis or in cases of ischemic infarcts that are secondarily infected. Moreover, immunosuppression is a major risk factor. Clinical examination usually reveals a combination of fever, left-upper-quadrant abdominal pain and vomiting. Laboratory findings are not constant. imaging is a necessary tool for establishing the diagnosis, with a choice between ultrasound and computed tomography. Treatment includes conservative measures, and surgical intervention. in children and in cases of solitary abscesses with a thick wall, percutaneous catheter drainage may be attempted. Otherwise, splenectomy is the preferred approach in most centers. Here, we present three cases of splenic abscess. in all three, splenectomy was performed, followed by rapid clinical improvement. These cases emphasize that current understanding of spleen abscess etiology is still limited, and a study for additional risk factors may be necessary.

关键词： Spleen Abscess Splenectomy infections Trauma

Synthesis,characterization and thermolysis of lanthanide metal nitrate complexes with 1,10-phenanthroline,Part-95

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Journal of Rare Earths 2014年第6期32卷 545-552页

作者： Nibha B.P.Baranwal Gurdip Singh constantin G.Daniliuc Department of Chemistry DDU Gorakhpur University Organisch–Chemisches institut Universitat Munster

The nitrate complexes of cerium, praseodymium and neodymium with 1,10-phenanthroline （phen） of general formula [Ln（phen）2（NO3）2（H2O）2]·NO3 （where, Ln=Ce, Pr and Nd） were prepared and characterized by X-ray crystallography. Thermolysis of these complexes was investigated by simultaneous thermogravimetry （TG） and differential thermal analysis （DTA）. isothermal TG was taken to evaluate the kinetic parameters using model fitting as well as model free isoconversional methods. The thermolytic pathways were also suggested, which involves decomposition followed by ignition. All the three complexes had coordination number ten and showed multistep decompositions. in order to evaluate the response of rapid heating, ignition delay （Di） measurements were undertaken. The activation energies for ignition were found to decrease in the order： Nd〉Pr〉Ce.

关键词： crystal structure metal nitrate kinetics isoconversional model fitting ignition delay rare earths

The human retinal stem niches could overlap a vascular anatomical pattern

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Neural Regeneration Research 2015年第1期10卷 39-40页

作者： Mugurel constantin Rusu Alexandra Diana Vrapciu Division of Anatomy Faculty of Dental Medicine"Carol Davila" University of Medicine and Pharmacy MEDCENTER Center of Excellence in Laboratory Medicine and Pathology international Society of Regenerative Medicine and Surgery (iSRMS)

Stem cells are undifferentiated cells which have the unique potential to self-renew and to supply, via intermediate stages of transit amplifying cells （TACs）, differentiated cells. With- in the stem cell niches not only heterologous cells, but also differentiated progeny of stem cells provide regulation to the stem cells parents. Stem cells can differentiate in various cell types during tissue maintenance or repair.

关键词： stem cell The human retinal stem niches could overlap a vascular anatomical pattern MSCs Figure

Electrochemical Study and Electrodeposition of Copper（i） in ionic Liquid-reline

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Chemical Research in Chinese Universities 2013年第5期29卷 991-997页

作者： POPESCU Ana-Maria COJOCARU Anca DONATH Cristina constantin Virgil Laboratory of Molten Salts "Hie Murgulescu" Institute of Physical Chemistry of Romanian Academy Bucharest 060021 Romania Department of Applied Physical Chemistry and Electrochemistry University Politehnica of Bucharest Bucharest 010737 Romania

The authors made the electrochemical studies on the electrode processes during copper electrodeposition with ionic liquids-reline as an electrolytic medium. Reline is a commercial name for a eutectic mixture of choline chloride and urea（1：2, molar ratio）. This new proposed method of copper deposition is an ecological one because the ionic liquids are recyclable, non-volatile and non-toxic. Cyclic voltammetry investigations were conducted at 343 and 353 K in choline chloride-urea（Reline） deep eutectic solvent with single salt CuCl（generally in 0.05--0.38 mol/L concentration range）. Electrochemical impedance spectroscopy investigations were conducted in choline chloride- urea ionic liquid with CuCi（0.05 mol/L）. We investigated both cathodic and anodic processes of Cu＋ ions at different sweep rates in this new electrolytic system based on choline chloride. We have proposed by this an alternative to the classical copper electrodeposition. Coefficient of diffusion, Do, for the system Reline-CuCl is presented and the value of D0 is 1.22× 10^-8 cm2/s.

关键词： ionic liquid Reline Electrodeposition Cu(i) Coefficient of diffusion

Electromagnetic Characteristics and Corrosion Resistance of New Magnetosoft Materials Based on Capsulated iron Powders

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Chemical Research in Chinese Universities 2020年第6期36卷 1326-1331页

作者： Alexander VETCHER Gennady GOVOR Olga DEMiDENKO Virgil constantin Ana Maria POPESCU Scientific-Practical Materials Research Centre National Academy of BelarusP.Brovki 19 Str.220072 MinskBelarus “ilieMurgulescu”institute of Physical Chemistry of Romanian Academy Laboratory of Electrochemistry and CorrosionSplaiullndependentei 202Bucharest 060021Romania

A new method of depositing an insulating multifunctional oxide coating on metal particles was *** coatings increase corrosion resistance and insulate metal particles from each *** base of capsulated by oxide coating water-atomized iron powder ASC100.29,new composite soft magnetic materials were synthesized,which are able of replacing electrical steel in ***,electromagnetic properties and corrosion characte-ristics of the obtained composites were *** was found that the synthesized composite materials have low elec-tromagnetic losses,high values of magnetic induction(up to 2.1 T)and good corrosion *** results demon-strate that the use of such materials in power supplies,c hokes,transformers,stators and rotors of electric machines and other products ensures their stable operation under various conditions.

关键词： Soft magnetic composite material iron powder insulating cover High-frequency transformer Stators and rotors of electro machine

Peri-Gondwanan terranes in the Romanian Carpathians:A review of their spatial distribution,origin,provenance,and evolution

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Geoscience Frontiers 2014年第3期5卷 395-411页

作者： ioan Balintoni.constantin Balica Mihai N.Ducea Horst-Peter Hann Department of Geology Babes-Bolyai University400084 Cluj-NapocaRomania Department of Geosciences The University of Arizona1040 E.4th StreetTucsonAZ 85721USA Faculty of Geology and Geophysics Bucharest UniversityStr.N.Balcescu Nr 1BucurestiRomania institut fr Geowissenschaften Universitt Tbingen72076 TbingenGermany

The basement of the Romanian Carpathians is made of Neoproterozoic to early Paleozoic peri- Gondwanan terranes variably involved in the Variscan orogeny, similarly to other basement terrains of Europe. They were hardly dismembered during the Alpine orogeny and traditionally have their own names in the three Carpathian areas. The Danubian domain of the South Carpathians comprises the Dragsan and Lainici-Paiius peri-Amazonian terranes. The Dragsan terrane originated within the ocean surrounding Rodinia and docked with Rodinia at -800 Ma. it does not contain Cadomian magmatism and consequently it is classified as an Avalonian extra-Cadomian terrane, The Lainici-Pfiius terrane is a Ganderian fragment strongly modified by Cadomian subduction-related magmatism, it is attached to the Moesia platform. The TisoviD terrane is an ophiolite that marks the boundary between Drfagsan and Lainici-Paius terranes. The other basement terranes of the Romanian Carpathians originated close to the Ordovician North- African orogen, as a result of the eastern Rheic Ocean opening and closure. Except for the Sebes-Lotru terrane that includes a lower metamorphic unit of Cadomian age, all the other terranes （Bretila, Tulghes, Negrisoara and Rebra in the East Carpathians, Somes, Biharia and Baia de Aries in the Apuseni mountains, Fagaras, Leaota, Carat and Pades in the South Carpathians） represent late Cambrian-Ordovician rock assemblages. Their provenance, is probably within paleo-nortbeast Africa, close to the Arabian-Nubian shield. The late Cambrian-Ordovician terranes are defined here as Carpathian-type terranes. According to their lithostratigraphy and origin, some are of continental margin magmatic arc setting, whereas others formed in rift and back-arc environment and closed to passive continental margin settings. in a paleo- geographic reconstruction, the continental margin magmatic arc terranes were first that drifted out, followed by the passive continental margin terranes with the b

关键词： Romanian Carpathians pre-Alpine terranes U-Pb Geochronology Avalonian-type and Carpathian-type terranes Tornquist Rheic and Paleotethyan sutures Ordovician North-African orogen