On The Dynamics and Design of a Two-body Wave Energy Converter
Liang, Changwei; Zuo, Lei
2016-09-01
A two-body wave energy converter oscillating in heave is studied in this paper. The energy is extracted through the relative motion between the floating and submerged bodies. A linearized model in the frequency domain is adopted to study the dynamics of such a two-body system with consideration of both the viscous damping and the hydrodynamic damping. The closed form solution of the maximum absorption power and corresponding power take-off parameters are obtained. The suboptimal and optimal designs for a two-body system are proposed based on the closed form solution. The physical insight of the optimal design is to have one of the damped natural frequencies of the two body system the same as, or as close as possible to, the excitation frequency. A case study is conducted to investigate the influence of the submerged body on the absorption power of a two-body system subjected to suboptimal and optimal design under regular and irregular wave excitations. It is found that the absorption power of the two-body system can be significantly higher than that of the single body system with the same floating buoy in both regular and irregular waves. In regular waves, it is found that the mass of the submerged body should be designed with an optimal value in order to achieve the maximum absorption power for the given floating buoy. The viscous damping on the submerged body should be as small as possible for a given mass in both regular and irregular waves.
Two-body relaxation in modified Newtonian dynamics
Ciotti, L
2004-01-01
A naive extension to MOND of the standard computation of the two-body relaxation time Tb implies that Tb is comparable to the crossing time regardless of the number N of stars in the system. This computation is questionable in view of the non-linearity of MOND's field equation. A non-standard approach to the calculation of Tb is developed that can be extended to MOND whenever discreteness noise generates force fluctuations that are small compared to the mean-field force. It is shown that this approach yields standard Newtonian results for systems in which the mean density profile is either plane-parallel or spherical. In the plane-parallel case we find that in the deep-MOND regime Tbb scales with N as in the Newtonian case, but is shorter by the square of the factor by which MOND enhances the gravitational force over its Newtonian value for the same system. Application of these results to dwarf galaxies and groups and clusters of galaxies reveals that in MOND luminosity segregation should be far advanced in g...
Electromagnetic two-body problem: recurrent dynamics in the presence of state-dependent delay
Energy Technology Data Exchange (ETDEWEB)
De Luca, Jayme [Departamento de Fisica, Universidade Federal de Sao Carlos, Caixa Postal 676, Sao Carlos, Sao Paulo 13565-905 (Brazil); Guglielmi, Nicola [Dipartimento di Matematica Pura ed Applicata, Universita degli Studi di L' Aquila, I-67010, L' Aquila (Italy); Humphries, Tony [Department of Mathematics and Statistics, McGill University, Montreal, Quebec H3A 2K6 (Canada); Politi, Antonio, E-mail: deluca@df.ufscar.b [Istituto dei Sistemi Complessi, CNR Via Madonna del Piano 10-Sesto, Fiorentino I-50019 (Italy)
2010-05-21
We study the electromagnetic two-body problem of classical electrodynamics as a prototype dynamical system with state-dependent delays. The equations of motion are analysed with reference to motion along a straight line in the presence of an electrostatic field. We consider the general electromagnetic equations of motion for point charges with advanced and retarded interactions and study two limits, (a) retarded-only interactions (Dirac electrodynamics) and (b) half-retarded plus half-advanced interactions (Wheeler-Feynman electrodynamics). A fixed point is created where the electrostatic field balances the Coulombian attraction, and we use local analysis near this fixed point to derive necessary conditions for a Hopf bifurcation. In case (a), we study a Hopf bifurcation about an unphysical fixed point and find that it is subcritical. In case (b), there is a Hopf bifurcation about a physical fixed point and we study several families of periodic orbits near this point. The bifurcating periodic orbits are illustrated and simulated numerically, by introducing a surrogate dynamical system into the numerical analysis which transforms future data into past data by exploiting the periodicity, thus obtaining systems with only delays.
Electromagnetic two-body problem: recurrent dynamics in the presence of state-dependent delay
De Luca, Jayme; Guglielmi, Nicola; Humphries, Tony; Politi, Antonio
2010-05-01
We study the electromagnetic two-body problem of classical electrodynamics as a prototype dynamical system with state-dependent delays. The equations of motion are analysed with reference to motion along a straight line in the presence of an electrostatic field. We consider the general electromagnetic equations of motion for point charges with advanced and retarded interactions and study two limits, (a) retarded-only interactions (Dirac electrodynamics) and (b) half-retarded plus half-advanced interactions (Wheeler-Feynman electrodynamics). A fixed point is created where the electrostatic field balances the Coulombian attraction, and we use local analysis near this fixed point to derive necessary conditions for a Hopf bifurcation. In case (a), we study a Hopf bifurcation about an unphysical fixed point and find that it is subcritical. In case (b), there is a Hopf bifurcation about a physical fixed point and we study several families of periodic orbits near this point. The bifurcating periodic orbits are illustrated and simulated numerically, by introducing a surrogate dynamical system into the numerical analysis which transforms future data into past data by exploiting the periodicity, thus obtaining systems with only delays.
Measurement of mixing and CP violation parameters in two-body charm decays
Aaij, R; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amhis, Y; Anderson, J; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Arrabito, L; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Bailey, D S; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bates, A; Bauer, C; Bauer, Th; Bay, A; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Bernet, R; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blanks, C; Blouw, J; Blusk, S; Bobrov, A; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Büchler-Germann, A; Burducea, I; Bursche, A; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chiapolini, N; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Collins, P; Comerma-Montells, A; Constantin, F; Contu, A; Cook, A; Coombes, M; Corti, G; Cowan, G A; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Capua, S; De Cian, M; De Lorenzi, F; De Miranda, J M; De Paula, L; De Simone, P; Decamp, D; Deckenhoff, M; Degaudenzi, H; Del Buono, L; Deplano, C; Derkach, D; Deschamps, O; Dettori, F; Dickens, J; Dijkstra, H; Diniz Batista, P; Domingo Bonal, F; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisele, F; Eisenhardt, S; Ekelhof, R; Eklund, L; Elsasser, Ch; Elsby, D; Esperante Pereira, D; Estève, L; Falabella, A; Fanchini, E; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Fernandez Albor, V; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Frank, M; Frei, C; Frosini, M; Furcas, S; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garnier, J-C; Garofoli, J; Garra Tico, J; Garrido, L; Gascon, D; Gaspar, C; Gauvin, N; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Gracianiv Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Haefeli, G; Haen, C; Haines, S C; Hampson, T; Hansmann-Menzemer, S; Harji, R; Harnew, N; Harrison, J; Harrison, P F; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Holubyev, K; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Huston, R S; Hutchcroft, D; Hynds, D; Iakovenko, V; Ilten, P; Imong, J; Jacobsson, R; Jaeger, A; Jahjah Hussein, M; Jans, E; Jansen, F; Jaton, P; Jean-Marie, B; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Keaveney, J; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kim, Y M; Knecht, M; Koppenburg, P; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kruzelecki, K; Kucharczyk, M; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Leroy, O; Lesiak, T; Li, L; Li Gioi, L; Lieng, M; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Luisier, J; Mac Raighne, A; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Magnin, J; Malde, S; Mamunur, R M D; Manca, G; Mancinelli, G; Mangiafave, N; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinez Santos, D; Massafferri, A; Mathe, Z; Matteuzzi, C; Matveev, M; Maurice, E; Maynard, B; Mazurov, A; McGregor, G; McNulty, R; Meissner, M; Merk, M; Merkel, J; Messi, R; Miglioranzi, S; Milanes, D A; Minard, M-N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Musy, M; Mylroie-Smith, J; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Nedos, M; Needham, M; Neufeld, N; Nguyen-Mau, C; Nicol, M; Niess, V; Nikitin, N; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, K; Palacios, J; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Paterson, S K; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petrella, A; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pie Valls, B; Pietrzyk, B; Pilař, T; Pinci, D; Plackett, R; Playfer, S; Plo Casasus, M; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Rinnert, K; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodrigues, F; Rodriguez Perez, P; Rogers, G J; Roiser, S; Romanovsky, V; Rosello, M; Rouvinet, J; Ruf, T; Ruiz, H; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santinelli, R; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schleich, S; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, A C; Smith, N A; Smith, E; Sobczak, K; Soler, F J P; Solomin, A; Soomro, F; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Topp-Joergensen, S; Torr, N; Tournefier, E; Tran, M T; Tsaregorodtsev, A; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urquijo, P; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Viaud, B; Videau, I; Vilasis-Cardona, X; Visniakov, J; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Voss, H; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Witzeling, W; Wotton, S A; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yushchenko, O; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhong, L; Zverev, E; Zvyagin, A
2012-01-01
A study of mixing and indirect CP violation in $D^0$ mesons through the determination of the parameters $y_{CP}$ and $A_\\Gamma$ is presented. The parameter $y_{CP}$ is the deviation from unity of the ratio of effective lifetimes measured in $D^0$ decays to the CP eigenstate $K^+K^-$ with respect to decays to the Cabibbo favoured mode $K^-\\pi^+$. The result measured using data collected by LHCb in 2010, corresponding to an integrated luminosity of $29~pb^{-1}$, is $$y_{CP} = (5.5\\pm6.3_{\\rm stat}\\pm4.1_{\\rm syst})\\times 10^{-3}.$$ The parameter $A_\\Gamma$ is the asymmetry of effective lifetimes measured in decays of $D^0$ and $\\overline{D}^0$ mesons to $K^+K^-$. The result is $$A_\\Gamma = (-5.9\\pm5.9_{\\rm stat}\\pm2.1_{\\rm syst})\\times 10^{-3}.$$ A data-driven technique is used to correct for lifetime-biasing effects.
Frederico, Tobias; Pace, Emanuele; Salme`, Giovanni
2010-01-01
The electromagnetic properties of the deuteron are investigated within a Light-Front Hamiltonian Dynamics framework, with a current operator that contains both one-body and two-body contributions. In this work, we are considering new two-body contributions, with a dynamical nature generated within a Yukawa model and a structure inspired by a recent analysis of the current operator, that acts on the three-dimensional valence component and fulfills the Ward-Takahashi identity. Preliminary results for the magnetic moment are shown.
The Sharma-Parthasarathy stochastic two-body problem
Energy Technology Data Exchange (ETDEWEB)
Cresson, J. [LMAP/Université de Pau, 64013 Pau (France); SYRTE/Observatoire de Paris, 75014 Paris (France); Pierret, F. [SYRTE/Observatoire de Paris, 75014 Paris (France); Puig, B. [IPRA/Université de Pau, 64013 Pau (France)
2015-03-15
We study the Sharma-Parthasarathy stochastic two-body problem introduced by Sharma and Parthasarathy in [“Dynamics of a stochastically perturbed two-body problem,” Proc. R. Soc. A 463, 979-1003 (2007)]. In particular, we focus on the preservation of some fundamental features of the classical two-body problem like the Hamiltonian structure and first integrals in the stochastic case. Numerical simulations are performed which illustrate the dynamical behaviour of the osculating elements as the semi-major axis, the eccentricity, and the pericenter. We also derive a stochastic version of Gauss’s equations in the planar case.
The Sharma-Parthasarathy stochastic two-body problem
Cresson, J.; Pierret, F.; Puig, B.
2015-03-01
We study the Sharma-Parthasarathy stochastic two-body problem introduced by Sharma and Parthasarathy in ["Dynamics of a stochastically perturbed two-body problem," Proc. R. Soc. A 463, 979-1003 (2007)]. In particular, we focus on the preservation of some fundamental features of the classical two-body problem like the Hamiltonian structure and first integrals in the stochastic case. Numerical simulations are performed which illustrate the dynamical behaviour of the osculating elements as the semi-major axis, the eccentricity, and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
Wind Farm Decentralized Dynamic Modeling With Parameters
DEFF Research Database (Denmark)
Soltani, Mohsen; Shakeri, Sayyed Mojtaba; Grunnet, Jacob Deleuran;
2010-01-01
Development of dynamic wind flow models for wind farms is part of the research in European research FP7 project AEOLUS. The objective of this report is to provide decentralized dynamic wind flow models with parameters. The report presents a structure for decentralized flow models with inputs from...
Software Development for JSA Dynamic Parameter Measurement
Institute of Scientific and Technical Information of China (English)
LUO; Huang-da
2013-01-01
We have developed a series of experiment measurement system for Jordan sub-critical assembly.The dynamic parameter measurement system is used for measuring the prompt neutron decaying constant,a physics parameter of reactor character.It mainly consists of a 3He neutron detector in the reactor core,
HYDRODYNAMIC INTERACTIONS BETWEEN TWO BODIES
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
On the basis of model tests, potential flow theory, and viscous Computational Fluid Dynamics (CFD) method, the hydrodynamic interactions between two underwater bodies were investigated to determine the influencing factors, changing rule, interaction mechanism, and appropriate methods describing them. Some special phenomena were discovered in two series of near-wall interaction experiments. The mathematical model and predicting methods were presented for interacting forces near wall, and the calculation results agreed well with the experimental ones. From the comparisons among numerical results with respect to nonviscosity, numerical results with respect to viscosity, and measured results, data on the influence of viscosity on hydrodynamic interactions were obtained. For hydrodynamic interaction related to multi-body unsteady motions with six degrees of freedom that is difficult to simulate in tests, numerical predictions of unsteady interacting forces were given.
Parameter identifiability of linear dynamical systems
Glover, K.; Willems, J. C.
1974-01-01
It is assumed that the system matrices of a stationary linear dynamical system were parametrized by a set of unknown parameters. The question considered here is, when can such a set of unknown parameters be identified from the observed data? Conditions for the local identifiability of a parametrization are derived in three situations: (1) when input/output observations are made, (2) when there exists an unknown feedback matrix in the system and (3) when the system is assumed to be driven by white noise and only output observations are made. Also a sufficient condition for global identifiability is derived.
Stochastic perturbation of the two-body problem
Jacky, Cresson; Bénédicte, Puig
2014-01-01
We study the impact of a stochastic perturbation on the classical two-body problem in particular concerning the preservation of first integrals and the Hamiltonian structure. Numerical simulations are performed which illustrate the dynamical behavior of the osculating elements as the semi-major axis, the eccentricity and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
Stochastic perturbation of the two-body problem
Cresson, J.; Pierret, F.; Puig, B.
2013-11-01
We study the impact of a stochastic perturbation on the classical two-body problem in particular concerning the preservation of first integrals and the Hamiltonian structure. Numerical simulations are performed which illustrate the dynamical behavior of the osculating elements as the semi-major axis, the eccentricity and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
High-energy two-body photoproduction
Salin, P
1974-01-01
Considers three aspects of two-body photoproduction reactions: vector meson production as a tool to investigate properties of diffractive reactions; the occurrence of a possible J=0 fixed pole in the Compton amplitude; and pseudoscalar meson photoproduction. (73 refs).
Two-Body Relaxation in Cosmological Simulations
Binney, J; Binney, James; Knebe, Alexander
2002-01-01
The importance of two-body relaxation in cosmological simulations is explored with simulations in which there are two species of particles. The cases of mass ratio sqrt(2):1 and 4:1 are investigated. Simulations are run with both a fixed softening length and adaptive softening using the publicly available codes GADGET and MLAPM, respectively. The effects of two-body relaxation are detected in both the density profiles of halos and the mass function of halos. The effects are more pronounced with a fixed softening length, but even in this case they are not so large as to suggest that results obtained with one mass species are significantly affected by two-body relaxation. The simulations that use adaptive softening are slightly less affected by two-body relaxation and produce slightly higher central densities in the largest halos. They run about three times faster than the simulations that use a fixed softening length.
Robustness of dynamic systems with parameter uncertainties
Balemi, S; Truöl, W
1992-01-01
Robust Control is one of the fastest growing and promising areas of research today. In many practical systems there exist uncertainties which have to be considered in the analysis and design of control systems. In the last decade methods were developed for dealing with dynamic systems with unstructured uncertainties such as HOO_ and £I-optimal control. For systems with parameter uncertainties, the seminal paper of V. L. Kharitonov has triggered a large amount of very promising research. An international workshop dealing with all aspects of robust control was successfully organized by S. P. Bhattacharyya and L. H. Keel in San Antonio, Texas, USA in March 1991. We organized the second international workshop in this area in Ascona, Switzer land in April 1992. However, this second workshop was restricted to robust control of dynamic systems with parameter uncertainties with the objective to concentrate on some aspects of robust control. This book contains a collection of papers presented at the International W...
Material loss in two-body collisions during planet formation
Werner, J.; Schäfer, C.; Maindl, T. I.; Burger, C.; Speith, R.
2016-02-01
During the formation process of a terrestrial planet, a planetary embryo does not only accrete smaller dust particles but also suffers collisions with larger planetesimals. When simulating these collisions, most N-body codes treat them as perfect merging events, i.e. the resulting body's mass is the sum of the previous ones. In our work, we aim to determine whether this assumption is a justified simplification, specifically focusing on bodies containing volatile elements, such as water. To analyze this, we have developed a new Smooth Particle Hydrodynamics (SPH) code that includes elasto-plastic dynamics, a damage model for brittle materials and self gravity. It makes use of the Compute Unified Device Architecture (CUDA) and runs on modern GPU architectures which allows for higher resolution in less calculation time. This enables us to take a precise look at two-body collisions and determine the amount of both transferred and ejected mass according to specific parameters such as mass ratio of impactor and target, porosity, impact velocity, impact angle and water distribution.
Which Dynamic Rupture Parameters can be Resolved?
Peyrat, S.; Olsen, K.; Madariaga, R.
2001-12-01
We use finite-difference simulations in models of the 1992 Mw 7.3 Landers earthquake to examine which dynamic rupture parameters may be recovered for large crustal earthquakes. By trial-and-error inversion Peyrat et al. (2001) found two simple models with constant slip-weakening friction which generated a satisfactory fit between synthetic and observed strong motion data: an asperity model, with spatially-varying initial stress and constant yield stress, and a barrier model with constant initial stress and spatially-varying yield stress. However, there is some evidence from inversion of seismic data for large earthquakes (i.e., Ide and Takeo, 1997, for the 1995 Kobe earthquake), that the slip-weakening distance Dc may vary spatially. In particular, Ide and Takeo found a larger Dc in the shallower parts of the crust compared to the deeper parts. Possible causes of such variation include the increase of elastic rigidity with depth and a fundamentally different friction in the near-surface layers. Here, we examine the effects of laterally and vertically varying Dc on the strong motion synthetics computed by our dynamic rupture models. We generate an alternative barrier model with constant initial and yield stress but spatially-varying Dc which, as our two previous rupture models of the Landers event, generate synthetics in agreement with strong motion data. Thus, we have constructed three well-posed mechanical models of the Landers earthquake that satisfy available strong motion data and which are end-members of a large family of dynamically correct models. Our findings confirm an earlier hypothesis that barrier and asperity models of an earthquake generate similar signature in the seismic radiation (Madariaga, 1979). Therefore, it may not be possible to separate stress and Dc using rupture modeling. Instead, we propose to characterize dynamic rupture propagation by the local non-dimensional parameter κ introduced by Madariaga and Olsen (2000), which is expressed in
Estimating parametes for systems with complicated dynamics
Goodwin, J; Goodwin, Justin; Brown, Reggie
1998-01-01
Changes in parameters of a physical device can eventually give way to catastrophic failure. In this paper we present a method for estimating the parameters of a device from time series data. We also examine the robustness of this method to noise in the data. For our examples, the parameter estimates are good to about two decimal places even at 0 dB signal to noise ratio.
Covariant Hamiltonian for the electromagnetic two-body problem
De Luca, Jayme
2005-09-01
We give a Hamiltonian formalism for the delay equations of motion of the electromagnetic two-body problem with arbitrary masses and with either repulsive or attractive interaction. This dynamical system based on action-at-a-distance electrodynamics appeared 100 years ago and it was popularized in the 1940s by the Wheeler and Feynman program to quantize it as a means to overcome the divergencies of perturbative QED. Our finite-dimensional implicit Hamiltonian is closed and involves no series expansions. As an application, the Hamiltonian formalism is used to construct a semiclassical canonical quantization based on the numerical trajectories of the attractive problem.
Identification of Dynamic Parameters for Robots with Elastic Joints
Directory of Open Access Journals (Sweden)
Loredana Zollo
2015-02-01
Full Text Available This paper presents a novel method for identifying dynamic parameters of robot manipulators with elastic joints. A procedure based on the Lagrangianm formulation of the dynamic model is proposed. Each term is inspected to search for a linear relationship with the dynamic parameters, thus enabling the linearization of robot dynamic model. Hence, the torque vector is expressed as the product of a regressor matrix, suitably defined by the vector of dynamic parameters. A parametric identification based on a least-squares technique is applied to determine dynamic parameters of robots with elastic joints. The correctness of the proposed procedure has been tested in simulation on two robotic structures with elastic joints of different complexity, that is, a 2-degree-of-freedom (dof and a 6-dof manipulator, controlled with a PD control in the joint space.
CADLIVE optimizer: web-based parameter estimation for dynamic models
Directory of Open Access Journals (Sweden)
Inoue Kentaro
2012-08-01
Full Text Available Abstract Computer simulation has been an important technique to capture the dynamics of biochemical networks. In most networks, however, few kinetic parameters have been measured in vivo because of experimental complexity. We develop a kinetic parameter estimation system, named the CADLIVE Optimizer, which comprises genetic algorithms-based solvers with a graphical user interface. This optimizer is integrated into the CADLIVE Dynamic Simulator to attain efficient simulation for dynamic models.
Fonseca, A C
2000-01-01
Realistic interactions are used to study sup 1 H(d, gamma) sup 3 He tensor observables in the energy range of 80 keV to 95 MeV deuteron laboratory energy, as well as the differential cross section for the two-body photodisintegration of sup 3 He. The Siegert form of the E1 multipole operator in the long-wavelength limit is taken as the sole component of the electromagnetic interaction. The three-body Faddeev equations for the bound-state and continuum wave functions are solved using the Paris, Argonne V14, Bonn-A, and Bonn-B potentials. The corresponding nucleon-nucleon t-matrices are represented in a separable form using the Ernst-Shakin-Thaler representation. The Coulomb force between protons is neglected and no three-nucleon force is included. The contribution of nucleon-nucleon P-wave components to the observables is carefully studied, not only in the angular distribution of the observables, but also as a function of the deuteron laboratory energy for fixed centre-of-mass angle. Comparison with data is sh...
Online Dynamic Parameter Estimation of Synchronous Machines
West, Michael R.
Traditionally, synchronous machine parameters are determined through an offline characterization procedure. The IEEE 115 standard suggests a variety of mechanical and electrical tests to capture the fundamental characteristics and behaviors of a given machine. These characteristics and behaviors can be used to develop and understand machine models that accurately reflect the machine's performance. To perform such tests, the machine is required to be removed from service. Characterizing a machine offline can result in economic losses due to down time, labor expenses, etc. Such losses may be mitigated by implementing online characterization procedures. Historically, different approaches have been taken to develop methods of calculating a machine's electrical characteristics, without removing the machine from service. Using a machine's input and response data combined with a numerical algorithm, a machine's characteristics can be determined. This thesis explores such characterization methods and strives to compare the IEEE 115 standard for offline characterization with the least squares approximation iterative approach implemented on a 20 h.p. synchronous machine. This least squares estimation method of online parameter estimation shows encouraging results for steady-state parameters, in comparison with steady-state parameters obtained through the IEEE 115 standard.
Open quantum system parameters from molecular dynamics
Wang, Xiaoqing; Wüster, Sebastian; Eisfeld, Alexander
2015-01-01
We extract the site energies and spectral densities of the Fenna-Matthews-Olson (FMO) pigment protein complex of green sulphur bacteria from simulations of molecular dynamics combined with energy gap calculations. Comparing four different combinations of methods, we investigate the origin of quantitative differences regarding site energies and spectral densities obtained previously in the literature. We find that different forcefields for molecular dynamics and varying local energy minima found by the structure relaxation yield significantly different results. Nevertheless, a picture averaged over these variations is in good agreement with experiments and some other theory results. Throughout, we discuss how vibrations external- or internal to the pigment molecules enter the extracted quantities differently and can be distinguished. Our results offer some guidance to set up more computationally intensive calculations for a precise determination of spectral densities in the future. These are required to determ...
On gravitational interactions between two bodies
Szybka, Sebastian J
2014-01-01
Many physicists, following Einstein, believe that the ultimate aim of theoretical physics is to find a unified theory of all interactions which would not depend on any free dimensionless constant, i.e., a dimensionless constant that is only empirically determinable. We do not know if such a theory exists. Moreover, if it exists, there seems to be no reason for it to be comprehensible for the human mind. On the other hand, as pointed out in Wigner's famous paper, human mathematics is unbelievably successful in natural science. This seeming paradox may be mitigated by assuming that the mathematical structure of physical reality has many `layers'. As time goes by, physicists discover new theories that correspond to the physical reality on the deeper and deeper level. In this essay, I will take a narrow approach and discuss the mathematical structure behind a single physical phenomenon - gravitational interaction between two bodies. The main aim of this essay is to put some recent developments of this topic in a ...
Parameter Estimation in Epidemiology: from Simple to Complex Dynamics
Aguiar, Maíra; Ballesteros, Sebastién; Boto, João Pedro; Kooi, Bob W.; Mateus, Luís; Stollenwerk, Nico
2011-09-01
We revisit the parameter estimation framework for population biological dynamical systems, and apply it to calibrate various models in epidemiology with empirical time series, namely influenza and dengue fever. When it comes to more complex models like multi-strain dynamics to describe the virus-host interaction in dengue fever, even most recently developed parameter estimation techniques, like maximum likelihood iterated filtering, come to their computational limits. However, the first results of parameter estimation with data on dengue fever from Thailand indicate a subtle interplay between stochasticity and deterministic skeleton. The deterministic system on its own already displays complex dynamics up to deterministic chaos and coexistence of multiple attractors.
Xu, Wenfu; Hu, Zhonghua; Zhang, Yu; Liang, Bin
2017-03-01
After being launched into space to perform some tasks, the inertia parameters of a space robotic system may change due to fuel consumption, hardware reconfiguration, target capturing, and so on. For precision control and simulation, it is required to identify these parameters on orbit. This paper proposes an effective method for identifying the complete inertia parameters (including the mass, inertia tensor and center of mass position) of a space robotic system. The key to the method is to identify two types of simple dynamics systems: equivalent single-body and two-body systems. For the former, all of the joints are locked into a designed configuration and the thrusters are used for orbital maneuvering. The object function for optimization is defined in terms of acceleration and velocity of the equivalent single body. For the latter, only one joint is unlocked and driven to move along a planned (exiting) trajectory in free-floating mode. The object function is defined based on the linear and angular momentum equations. Then, the parameter identification problems are transformed into non-linear optimization problems. The Particle Swarm Optimization (PSO) algorithm is applied to determine the optimal parameters, i.e. the complete dynamic parameters of the two equivalent systems. By sequentially unlocking the 1st to nth joints (or unlocking the nth to 1st joints), the mass properties of body 0 to n (or n to 0) are completely identified. For the proposed method, only simple dynamics equations are needed for identification. The excitation motion (orbit maneuvering and joint motion) is also easily realized. Moreover, the method does not require prior knowledge of the mass properties of any body. It is general and practical for identifying a space robotic system on-orbit.
Identification of dynamic parameters for fireballs
Gritsevich, M.
2007-08-01
Now a big actual material on photographic registration of meteoric bodies trajectories in the Earth's atmosphere is accumulated. The greatest number of pictures is made by the four fireball networks which functioned at various times in the USA, Canada, the Europe and Spain. Approximation of real data by theoretical dependencies allows to receive the additional estimations which are not following directly from observations. Here the algorithm of selection of parameters, at which the theoretical dependence of height on speed in the best way approximates data of observations, is offered. The basic difference from previous works is approach of the set points by the analytical solution of the meteoric physics equations. The method was applied to some bright meteors from the Canadian network, Prairie network, and also to the Beneshov bolide, one of the largest, registered by the European network. Correct mathematical modeling of the meteoric phenomena in an atmosphere is necessary for the subsequent estimation of key parameters: extra-atmospheric mass, ablation coefficient, effective enthalpy of evaporation. In turn, these data are important for some applications: researches of asteroid-comet hazard, measures of planetary defense, and also for search of the bodies, capable to reach the Earth's surface.
One dimensional scattering of a two body interacting system by an infinite wall
Moro, A M; Gomez-Camacho, J
2010-01-01
The one-dimensional scattering of a two body interacting system by an infinite wall is studied in a quantum-mechanical framework. This problem contains some of the dynamical features present in the collision of atomic, molecular and nuclear systems. The scattering problem is solved exactly, for the case of a harmonic interaction between the fragments. The exact result is used to assess the validity of two different approximations to the scattering process. The adiabatic approximation, which considers that the relative co-ordinate is frozen during the scattering process, is found to be inadequate for this problem. The uncorrelated scattering approximation, which neglects the correlation between the fragments, gives results in accordance with the exact calculations when the scattering energy is high compared to the oscillator parameter.
Micromagnetic simulation of two-body magnetic nanoparticles
Li, Fei; Lu, Jincheng; Yang, Yu; Lu, Xiaofeng; Tang, Rujun; Sun, Z. Z.
2017-05-01
Field-induced magnetization dynamics was investigated in a system of two magnetic nanoparticles with uniaxial anisotropies and magnetostatic interaction. By using the micromagnetic simulation, ultralow switching field strength was found when the separation distance between the two particles reaches a critical small value on nanometer scale in the perpendicular configuration where the anisotropic axes of the two particles are perpendicular to the separation line. The switching field increases sharply when the separation is away from the critical distance. The same results were observed when varying the radius of particles. The micromagnetic results are consistent with the previous theoretical prediction where dipolar interaction between two single-domain magnetic particles was considered. Our present simulations offered further proofs and possibilities for the low-power applications of information storage as the two-body magnetic nanoparticles could be implemented as a composite information bit.
External synchronization of two dynamical systems with uncertain parameters
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
External synchronization is addressed as two or more dynamical systems with synchronous motions,which is also regarded as master-slave system.In this paper,two dynamical systems,one employs a hysteretic term to model the friction phenomenon,the other involves a hardening stiffness component with the third order of displacement due to flexible deformation,are controlled to converge to the same trajectory.The control strategy is extended from feedback control for all parameters known to adaptive control for linear parameters unknown and all parameters unknown.The slave system can keep synchronous motions with the movements of master via the designed control strategy even all the parameters are not known.The stability of synchronization error,the transient process into synchronization and the effects of parameters on the designed controller using different control strategies are investigated.The simulation results unfold the feasibility and effectiveness of this synchronization method.
Optimal parameters for the FFA-Beddoes dynamic stall model
Energy Technology Data Exchange (ETDEWEB)
Bjoerck, A.; Mert, M. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden); Madsen, H.A. [Risoe National Lab., Roskilde (Denmark)
1999-03-01
Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for wind turbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empiricial parameters. In this paper a study of finding appropriate parameters to use with the Beddoes-Leishman model is discussed. Minimisation of the `tracking error` between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters. The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations, give rise to quite different predictions of aerodynamic damping which is discussed. (au)
Dynamic Load Model using PSO-Based Parameter Estimation
Taoka, Hisao; Matsuki, Junya; Tomoda, Michiya; Hayashi, Yasuhiro; Yamagishi, Yoshio; Kanao, Norikazu
This paper presents a new method for estimating unknown parameters of dynamic load model as a parallel composite of a constant impedance load and an induction motor behind a series constant reactance. An adequate dynamic load model is essential for evaluating power system stability, and this model can represent the behavior of actual load by using appropriate parameters. However, the problem of this model is that a lot of parameters are necessary and it is not easy to estimate a lot of unknown parameters. We propose an estimating method based on Particle Swarm Optimization (PSO) which is a non-linear optimization method by using the data of voltage, active power and reactive power measured at voltage sag.
Drawing Dynamical and Parameters Planes of Iterative Families and Methods
Directory of Open Access Journals (Sweden)
Francisco I. Chicharro
2013-01-01
Full Text Available The complex dynamical analysis of the parametric fourth-order Kim’s iterative family is made on quadratic polynomials, showing the MATLAB codes generated to draw the fractal images necessary to complete the study. The parameter spaces associated with the free critical points have been analyzed, showing the stable (and unstable regions where the selection of the parameter will provide us the excellent schemes (or dreadful ones.
Drawing dynamical and parameters planes of iterative families and methods.
Chicharro, Francisco I; Cordero, Alicia; Torregrosa, Juan R
2013-01-01
The complex dynamical analysis of the parametric fourth-order Kim's iterative family is made on quadratic polynomials, showing the MATLAB codes generated to draw the fractal images necessary to complete the study. The parameter spaces associated with the free critical points have been analyzed, showing the stable (and unstable) regions where the selection of the parameter will provide us the excellent schemes (or dreadful ones).
Interacting Dark Fluid in Anisotropic Universe with Dynamical Deceleration Parameter
Adhav, K. S.; Bokey, V. D.; Bansod, A. S.; Munde, S. L.
2016-10-01
In this paper we have studied the anisotropic and homogeneous Bianchi Type-I and V universe filled with Interacting Dark Matter and Holographic Dark Energy. The solutions of field equations are obtained for both models under the assumption of linearly varying deceleration parameter which yields dynamical deceleration parameter. It has been observed that the anisotropy of expansion dies out very quickly (soon after inflation) in both models (B-I, B-V). The physical and geometrical parameters for the both models have been obtained and discussed in details.
Two-body dissipation effects on synthesis of superheavy elements
Tohyama, M
2015-01-01
To investigate the two-body dissipation effects on the synthesis of superheavy elements, we calculate low-energy collisions of the $N=50$ isotones ($^{82}$Ge, $^{84}$Se, $^{86}$Kr and $^{88}$Sr) on $^{208}$Pb using the time-dependent density-matrix theory (TDDM). TDDM is an extension of the time-dependent Hartree-Fock (TDHF) theory and can determine the time evolution of one-body and two-body density matrices. Thus TDDM describes both one-body and two-body dissipation of collective energies. It is shown that the two-body dissipation may increase fusion cross sections and enhance the synthesis of superheavy elements.
A software for parameter estimation in dynamic models
Directory of Open Access Journals (Sweden)
M. Yuceer
2008-12-01
Full Text Available A common problem in dynamic systems is to determine parameters in an equation used to represent experimental data. The goal is to determine the values of model parameters that provide the best fit to measured data, generally based on some type of least squares or maximum likelihood criterion. In the most general case, this requires the solution of a nonlinear and frequently non-convex optimization problem. Some of the available software lack in generality, while others do not provide ease of use. A user-interactive parameter estimation software was needed for identifying kinetic parameters. In this work we developed an integration based optimization approach to provide a solution to such problems. For easy implementation of the technique, a parameter estimation software (PARES has been developed in MATLAB environment. When tested with extensive example problems from literature, the suggested approach is proven to provide good agreement between predicted and observed data within relatively less computing time and iterations.
Improvement parameters in dynamic compaction adjacent to the slopes
Directory of Open Access Journals (Sweden)
Elham Ghanbari
2015-04-01
Full Text Available Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM. The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.
Improvement parameters in dynamic compaction adjacent to the slopes
Institute of Scientific and Technical Information of China (English)
Elham Ghanbari; Amir Hamidi
2015-01-01
Dynamic compaction is a cost-effective method commonly used for improvement of sandy soils. A number of researchers have investigated experimentally and numerically the improvement parameters of soils using dynamic compaction, such as crater depth, improvement depth, and radial improvement, however, these parameters are not studied for improvement adjacent to the slopes or trenches. In this research, four different slopes with different inclinations are modeled numerically using the finite element code ABAQUS, and impact loads of dynamic compaction are applied. The static factors of safety are kept similar for all trenches and determined numerically by application of gravity loads to the slope using strength reduction method (SRM). The analysis focuses on crater depth and improvement region which are compared to the state of flat ground. It can be observed that compacted area adjacent to the slopes is narrower and slightly away from the slope compared to the flat state. Moreover, crater depth increases with increase in slope inclination.
Dynamic systems models new methods of parameter and state estimation
2016-01-01
This monograph is an exposition of a novel method for solving inverse problems, a method of parameter estimation for time series data collected from simulations of real experiments. These time series might be generated by measuring the dynamics of aircraft in flight, by the function of a hidden Markov model used in bioinformatics or speech recognition or when analyzing the dynamics of asset pricing provided by the nonlinear models of financial mathematics. Dynamic Systems Models demonstrates the use of algorithms based on polynomial approximation which have weaker requirements than already-popular iterative methods. Specifically, they do not require a first approximation of a root vector and they allow non-differentiable elements in the vector functions being approximated. The text covers all the points necessary for the understanding and use of polynomial approximation from the mathematical fundamentals, through algorithm development to the application of the method in, for instance, aeroplane flight dynamic...
Analytical treatment of the two-body problem with slowly varying mass
Rahoma, W. A.; Abd El-Salam, F. A.; Ahmed, M. K.
2009-12-01
The present work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.
Analytical Treatment of the Two-Body Problem with Slowly Varying Mass
Indian Academy of Sciences (India)
W. A. Rahoma; F. A. Abd El-Salam; M. K. Ahmed
2009-09-01
The present work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.
METAHEURISTIC OPTIMIZATION METHODS FOR PARAMETERS ESTIMATION OF DYNAMIC SYSTEMS
Directory of Open Access Journals (Sweden)
V. Panteleev Andrei
2017-01-01
Full Text Available The article considers the usage of metaheuristic methods of constrained global optimization: “Big Bang - Big Crunch”, “Fireworks Algorithm”, “Grenade Explosion Method” in parameters of dynamic systems estimation, described with algebraic-differential equations. Parameters estimation is based upon the observation results from mathematical model behavior. Their values are derived after criterion minimization, which describes the total squared error of state vector coordinates from the deduced ones with precise values observation at different periods of time. Paral- lelepiped type restriction is imposed on the parameters values. Used for solving problems, metaheuristic methods of constrained global extremum don’t guarantee the result, but allow to get a solution of a rather good quality in accepta- ble amount of time. The algorithm of using metaheuristic methods is given. Alongside with the obvious methods for solving algebraic-differential equation systems, it is convenient to use implicit methods for solving ordinary differen- tial equation systems. Two ways of solving the problem of parameters evaluation are given, those parameters differ in their mathematical model. In the first example, a linear mathematical model describes the chemical action parameters change, and in the second one, a nonlinear mathematical model describes predator-prey dynamics, which characterize the changes in both kinds’ population. For each of the observed examples there are calculation results from all the three methods of optimization, there are also some recommendations for how to choose methods parameters. The obtained numerical results have demonstrated the efficiency of the proposed approach. The deduced parameters ap- proximate points slightly differ from the best known solutions, which were deduced differently. To refine the results one should apply hybrid schemes that combine classical methods of optimization of zero, first and second orders and
A new method for parameter estimation in nonlinear dynamical equations
Wang, Liu; He, Wen-Ping; Liao, Le-Jian; Wan, Shi-Quan; He, Tao
2015-01-01
Parameter estimation is an important scientific problem in various fields such as chaos control, chaos synchronization and other mathematical models. In this paper, a new method for parameter estimation in nonlinear dynamical equations is proposed based on evolutionary modelling (EM). This will be achieved by utilizing the following characteristics of EM which includes self-organizing, adaptive and self-learning features which are inspired by biological natural selection, and mutation and genetic inheritance. The performance of the new method is demonstrated by using various numerical tests on the classic chaos model—Lorenz equation (Lorenz 1963). The results indicate that the new method can be used for fast and effective parameter estimation irrespective of whether partial parameters or all parameters are unknown in the Lorenz equation. Moreover, the new method has a good convergence rate. Noises are inevitable in observational data. The influence of observational noises on the performance of the presented method has been investigated. The results indicate that the strong noises, such as signal noise ratio (SNR) of 10 dB, have a larger influence on parameter estimation than the relatively weak noises. However, it is found that the precision of the parameter estimation remains acceptable for the relatively weak noises, e.g. SNR is 20 or 30 dB. It indicates that the presented method also has some anti-noise performance.
A Bayesian framework for parameter estimation in dynamical models.
Directory of Open Access Journals (Sweden)
Flávio Codeço Coelho
Full Text Available Mathematical models in biology are powerful tools for the study and exploration of complex dynamics. Nevertheless, bringing theoretical results to an agreement with experimental observations involves acknowledging a great deal of uncertainty intrinsic to our theoretical representation of a real system. Proper handling of such uncertainties is key to the successful usage of models to predict experimental or field observations. This problem has been addressed over the years by many tools for model calibration and parameter estimation. In this article we present a general framework for uncertainty analysis and parameter estimation that is designed to handle uncertainties associated with the modeling of dynamic biological systems while remaining agnostic as to the type of model used. We apply the framework to fit an SIR-like influenza transmission model to 7 years of incidence data in three European countries: Belgium, the Netherlands and Portugal.
Service Parameter Exposure and Dynamic Service Negotiation in SDN Environments
Institute of Scientific and Technical Information of China (English)
M. Boucadair; C. Jacquenet
2014-01-01
Software-defined networking (SDN) is a generic term and one of the major interests of the telecoms industry (and beyond) over the past two years. However, defining SDN is a somewhat controversial exercise. The claimed flexibility, as well as other presumed as-sets of SDN, should be carefully investigated. In particular, the use of SDN to dynamically provision network services suggests the introduction of a certain level of automation in the overall network service delivery process, from service parameter negotiation to delivery and operation. This paper aims to clarify the SDN landscape and focuses on two main aspects of the SDN framework: net-work abstraction, and dynamic parameter exposure and negotiation.
Ignition Dynamic Parameters for Coke in Cement Calciners
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The mathematical ignition model was established and researches of ignition dynamic parameters for coke in some typical coal samples from cement plants was carried out according to circumstances of coal combusted in cement plants.In order to get the ignitioin temperature Tpi of carbon particles more accurately,the temperature rising experimental method was used and the actual heating circumstances for pulverized coal in calciners(in cement plants)were also considered.With this method,the accurate determination of the ignition temperature of coke in coal was achieved,so as to get some ignition dynamic parameters.These research results provide a theoretical basis for investigating coal ignition characteristics more scientifically and more accurately.
Dynamical Evolution of Young Embedded Clusters: A Parameter Space Survey
Proszkow, Eva-Marie
2009-01-01
This paper investigates the dynamical evolution of embedded stellar clusters from the protocluster stage, through the embedded star-forming phase, and out to ages of 10 Myr -- after the gas has been removed from the cluster. The relevant dynamical properties of young stellar clusters are explored over a wide range of possible star formation environments using N-body simulations. Many realizations of equivalent initial conditions are used to produce robust statistical descriptions of cluster evolution including the cluster bound fraction, radial probability distributions, as well as the distributions of close encounter distances and velocities. These cluster properties are presented as a function of parameters describing the initial configuration of the cluster, including the initial cluster membership N, initial stellar velocities, cluster radii, star formation efficiency, embedding gas dispersal time, and the degree of primordial mass segregation. The results of this parameter space survey, which includes ab...
Dynamic Experiments for Bioprocess Parameter Optimization with Extreme Halophilic Archaea
Directory of Open Access Journals (Sweden)
Bettina Lorantfy
2013-11-01
Full Text Available The to-date studies on extreme halophiles were focused on shake flask cultivations. Bioreactor technology with quantitative approaches can offer a wide variety of biotechnological applications to exploit the special biochemical features of halophiles. Enabling industrial use of Haloferax mediterranei, finding the optima of cultivation parameters is of high interest. In general, process parameter optimizations were mainly carried out with laborious and time-consuming chemostat cultures. This work offers a faster alternative for process parameter optimization by applying temperature ramps and pH shifts on a halophilic continuous bioreactor culture. Although the hydraulic equilibrium in continuous culture is not reached along the ramps, the main effects on the activity from the dynamic studies can still be concluded. The results revealed that the optimal temperature range may be limited at the lower end by the activity of the primary metabolism pathways. At the higher end, the mass transfer of oxygen between the gaseous and the liquid phase can be limiting for microbial growth. pH was also shown to be a key parameter for avoiding overflow metabolism. The obtained experimental data were evaluated by clustering with multivariate data analyses. Showing the feasibility on a halophilic example, the presented dynamic methodology offers a tool for accelerating bioprocess development.
Estimating Arrhenius parameters using temperature programmed molecular dynamics
Imandi, Venkataramana; Chatterjee, Abhijit
2016-07-01
Kinetic rates at different temperatures and the associated Arrhenius parameters, whenever Arrhenius law is obeyed, are efficiently estimated by applying maximum likelihood analysis to waiting times collected using the temperature programmed molecular dynamics method. When transitions involving many activated pathways are available in the dataset, their rates may be calculated using the same collection of waiting times. Arrhenius behaviour is ascertained by comparing rates at the sampled temperatures with ones from the Arrhenius expression. Three prototype systems with corrugated energy landscapes, namely, solvated alanine dipeptide, diffusion at the metal-solvent interphase, and lithium diffusion in silicon, are studied to highlight various aspects of the method. The method becomes particularly appealing when the Arrhenius parameters can be used to find rates at low temperatures where transitions are rare. Systematic coarse-graining of states can further extend the time scales accessible to the method. Good estimates for the rate parameters are obtained with 500-1000 waiting times.
Estimating Arrhenius parameters using temperature programmed molecular dynamics.
Imandi, Venkataramana; Chatterjee, Abhijit
2016-07-21
Kinetic rates at different temperatures and the associated Arrhenius parameters, whenever Arrhenius law is obeyed, are efficiently estimated by applying maximum likelihood analysis to waiting times collected using the temperature programmed molecular dynamics method. When transitions involving many activated pathways are available in the dataset, their rates may be calculated using the same collection of waiting times. Arrhenius behaviour is ascertained by comparing rates at the sampled temperatures with ones from the Arrhenius expression. Three prototype systems with corrugated energy landscapes, namely, solvated alanine dipeptide, diffusion at the metal-solvent interphase, and lithium diffusion in silicon, are studied to highlight various aspects of the method. The method becomes particularly appealing when the Arrhenius parameters can be used to find rates at low temperatures where transitions are rare. Systematic coarse-graining of states can further extend the time scales accessible to the method. Good estimates for the rate parameters are obtained with 500-1000 waiting times.
Novel metaheuristic for parameter estimation in nonlinear dynamic biological systems
Directory of Open Access Journals (Sweden)
Banga Julio R
2006-11-01
Full Text Available Abstract Background We consider the problem of parameter estimation (model calibration in nonlinear dynamic models of biological systems. Due to the frequent ill-conditioning and multi-modality of many of these problems, traditional local methods usually fail (unless initialized with very good guesses of the parameter vector. In order to surmount these difficulties, global optimization (GO methods have been suggested as robust alternatives. Currently, deterministic GO methods can not solve problems of realistic size within this class in reasonable computation times. In contrast, certain types of stochastic GO methods have shown promising results, although the computational cost remains large. Rodriguez-Fernandez and coworkers have presented hybrid stochastic-deterministic GO methods which could reduce computation time by one order of magnitude while guaranteeing robustness. Our goal here was to further reduce the computational effort without loosing robustness. Results We have developed a new procedure based on the scatter search methodology for nonlinear optimization of dynamic models of arbitrary (or even unknown structure (i.e. black-box models. In this contribution, we describe and apply this novel metaheuristic, inspired by recent developments in the field of operations research, to a set of complex identification problems and we make a critical comparison with respect to the previous (above mentioned successful methods. Conclusion Robust and efficient methods for parameter estimation are of key importance in systems biology and related areas. The new metaheuristic presented in this paper aims to ensure the proper solution of these problems by adopting a global optimization approach, while keeping the computational effort under reasonable values. This new metaheuristic was applied to a set of three challenging parameter estimation problems of nonlinear dynamic biological systems, outperforming very significantly all the methods previously
Multinucleon Ejection Model for Two Body Current Neutrino Interactions
Energy Technology Data Exchange (ETDEWEB)
Sobczyk, Jan T.; /Fermilab
2012-06-01
A model is proposed to describe nucleons ejected from a nucleus as a result of two-body-current neutrino interactions. The model can be easily implemented in Monte Carlo neutrino event generators. Various possibilities to measure the two-body-current contribution are discussed. The model can help identify genuine charge current quasielastic events and allow for a better determination of the systematic error on neutrino energy reconstruction in neutrino oscillation experiments.
Parameters Identification for a Composite Piezoelectric Actuator Dynamics
Directory of Open Access Journals (Sweden)
Mohammad Saadeh
2015-03-01
Full Text Available This work presents an approach for identifying the model of a composite piezoelectric (PZT bimorph actuator dynamics, with the objective of creating a robust model that can be used under various operating conditions. This actuator exhibits nonlinear behavior that can be described using backlash and hysteresis. A linear dynamic model with a damping matrix that incorporates the Bouc–Wen hysteresis model and the backlash operators is developed. This work proposes identifying the actuator’s model parameters using the hybrid master-slave genetic algorithm neural network (HGANN. In this algorithm, the neural network exploits the ability of the genetic algorithm to search globally to optimize its structure, weights, biases and transfer functions to perform time series analysis efficiently. A total of nine datasets (cases representing three different voltage amplitudes excited at three different frequencies are used to train and validate the model. Four cases are considered for training the NN architecture, connection weights, bias weights and learning rules. The remaining five cases are used to validate the model, which produced results that closely match the experimental ones. The analysis shows that damping parameters are inversely proportional to the excitation frequency. This indicates that the suggested hysteresis model is too general for the PZT model in this work. It also suggests that backlash appears only when dynamic forces become dominant.
Dynamic control for nanostructures through slowly ramping parameters
Yoo, Jaeyun; Blick, Robert; Ahn, Kang-Hun
2016-06-01
We propose a nanostructure control method which uses slowly ramping parameters. We demonstrate the dynamics of this method in both a nonlinear classical system and a quantum system. When a quantum mechanical two-level atom (quantum dot) is irradiated by an electric field with a slowly increasing frequency, there exists a sudden transition from ground (excited) to excited (ground) state. This occurs when the ramping rate is smaller than the square of the Rabi frequency. The transition arises when its "instant frequency"—the time derivative of the driving field phase—matches the resonance frequency, satisfying the Fermi golden rule. We also find that the parameter ramping is an efficient control manner for classical nanomechanical shuttles. For ramping of driving amplitudes, the shuttle's mechanical oscillation is amplified and even survives when the ramping is stopped outside the original oscillation region. This strange oscillation is due to the entrance into a multistable dynamic region in phase space. For ramping of driving frequencies, an onset of oscillation arises when the instant frequency enters the oscillation region. Thus, regardless of being classical or quantum, the instant frequency is physically relevant. We discuss in which conditions the dynamic control is efficient.
Dynamic Routing of IP Traffic Based on QOS Parameters
Directory of Open Access Journals (Sweden)
Martin Kriška
2014-07-01
Full Text Available The article looks into the current state of the art of dynamic routing protocols with respect to their possibilities to react to changes in the Quality of Service when selecting the best route towards a destination network. New options that could leverage information about the ever changing QoS parameters for data communication are analysed and a Cisco Performance Routing solution is described more in detail. The practical part of this work focuses on a design and implementation of a test bed that provides ascalable laboratory architecture to manipulate QoS parameters of different data communications flowing through it. The test bed is used in various use cases that were used to evaluate Cisco Performance Routing optimization capabilities in different scenarios.
Parameter Tuning of Three-Flavor Dynamical Anisotropic Clover Action
Energy Technology Data Exchange (ETDEWEB)
Huey-Wen Lin; Robert G. Edwards; Balint Joo
2007-08-04
In this work, we perform parameter tuning with dynamical anisotropic clover lattices using the Schr\\"odinger functional and stout-smearing in the fermion field. We find that $\\xi_R/\\xi_0$ is relatively close to 1 in our parameter search, which allows us to fix $\\xi_0$ in our runs. We proposed to determine the gauge and fermion anisotropy in a Schr\\"odinger-background small box using Wilson loop ratios and PCAC masses. We demonstrate that these ideas are equivalent to but more efficient than the conventional meson dispersion approach. The spatial and temporal clover coefficients are fixed to the tree-level tadpole-improved clover values, and we demonstrate that they satisfy the nonperturbative condition determined by Schr\\"odinger functional method.
Control of complex dynamics and chaos in distributed parameter systems
Energy Technology Data Exchange (ETDEWEB)
Chakravarti, S.; Marek, M.; Ray, W.H. [Univ. of Wisconsin, Madison, WI (United States)
1995-12-31
This paper discusses a methodology for controlling complex dynamics and chaos in distributed parameter systems. The reaction-diffusion system with Brusselator kinetics, where the torus-doubling or quasi-periodic (two characteristic incommensurate frequencies) route to chaos exists in a defined range of parameter values, is used as an example. Poincare maps are used for characterization of quasi-periodic and chaotic attractors. The dominant modes or topos, which are inherent properties of the system, are identified by means of the Singular Value Decomposition. Tested modal feedback control schemas based on identified dominant spatial modes confirm the possibility of stabilization of simple quasi-periodic trajectories in the complex quasi-periodic or chaotic spatiotemporal patterns.
Multi-parameter quantification of wet eruption dynamics (Invited)
Schipper, C.; Burgisser, A.; Le Voyer, M.; White, J. D.
2013-12-01
Processes observed during the extremely well documented eruption of Surtsey, Iceland (1963-67), highlighted that magma-water interaction affects eruption dynamics. Although 2013 marks the 50th anniversary of this canonical eruption, many specific aspects of Surtseyan eruption dynamics, and magma-water interaction in general, remain only qualitatively described. For example, eruptions or phases thereof are often referred to as 'phreatomagmatic', without any discussion or identification of specific geometries and interactive volumes of the magma-water interaction involved. Moving toward a more quantitative understanding requires that all types of information: observational, textural, geochemical, and thermodynamic, be combined to effectively normalize the heterogeneity that is inherent to wet eruptions, and to yield specific descriptors of how magma and water (+/- solid contaminants) interact in style-defining ways. We explore the hypothesis that Surtseyan dynamics result from mingling between actively degassing and vesiculating magma, and slurries of previously erupted material in a flooded vent. Magmatic textures and properties can be explained by co-tracking: volatiles in phenocryst-hosted melt inclusions, the composition of gases emitted during the eruption, and evolution of magma porosity/permeability. Mingling of magma with water-saturated slurry can be identified in the textures of compound clasts over a range of grain sizes. Depending on key mingling parameters, including: the magma's porosity/permeability, the magma-slurry mixing ratio, and the slurry's particle-water mass ratio, several characteristic features of Surtseyan eruptions can be explained. The low-pressure expansion of superheated water in a coarsely mingled, saturated slurry can initiate Surtseyan cock's tail jets by imparting momentum to composite bombs at the jets' leading edges. Finer-scale mingling ensures that vapour formed within ballistic bombs discharges over timescales longer than their
Sensitivity analysis of random two-body interactions
Johnson, Calvin W
2010-01-01
The input to the configuration-interaction shell model includes many dozens or hundreds of independent two-body matrix elements. Previous studies have shown that when fitting to experimental low-lying spectra, the greatest sensitivity is to only a few linear combinations of matrix elements. Here we consider interactions drawn from the two-body random ensemble, or TBRE, and find that the low-lying spectra are also most sensitive to only a few linear combinations of two-body matrix elements, in a fashion nearly indistinguishable from an interaction empirically fit to data. We find in particular the spectra for both the random and empirical interactions are sensitive to similar matrix elements, which we analyze using monopole and contact interactions.
Parameter Estimation of Nonlinear Systems by Dynamic Cuckoo Search.
Liao, Qixiang; Zhou, Shudao; Shi, Hanqing; Shi, Weilai
2017-04-01
In order to address with the problem of the traditional or improved cuckoo search (CS) algorithm, we propose a dynamic adaptive cuckoo search with crossover operator (DACS-CO) algorithm. Normally, the parameters of the CS algorithm are kept constant or adapted by empirical equation that may result in decreasing the efficiency of the algorithm. In order to solve the problem, a feedback control scheme of algorithm parameters is adopted in cuckoo search; Rechenberg's 1/5 criterion, combined with a learning strategy, is used to evaluate the evolution process. In addition, there are no information exchanges between individuals for cuckoo search algorithm. To promote the search progress and overcome premature convergence, the multiple-point random crossover operator is merged into the CS algorithm to exchange information between individuals and improve the diversification and intensification of the population. The performance of the proposed hybrid algorithm is investigated through different nonlinear systems, with the numerical results demonstrating that the method can estimate parameters accurately and efficiently. Finally, we compare the results with the standard CS algorithm, orthogonal learning cuckoo search algorithm (OLCS), an adaptive and simulated annealing operation with the cuckoo search algorithm (ACS-SA), a genetic algorithm (GA), a particle swarm optimization algorithm (PSO), and a genetic simulated annealing algorithm (GA-SA). Our simulation results demonstrate the effectiveness and superior performance of the proposed algorithm.
Wave Function Structure in Two-Body Random Matrix Ensembles
Kaplan, L; Kaplan, Lev; Papenbrock, Thomas
2000-01-01
We study the structure of eigenstates in two-body interaction random matrix ensembles and find significant deviations from random matrix theory expectations. The deviations are most prominent in the tails of the spectral density and indicate localization of the eigenstates in Fock space. Using ideas related to scar theory we derive an analytical formula that relates fluctuations in wave function intensities to fluctuations of the two-body interaction matrix elements. Numerical results for many-body fermion systems agree well with the theoretical predictions.
Studying the effects of dynamical parameters on reactor core temperature
Directory of Open Access Journals (Sweden)
R Khodabakhsh
2015-01-01
Full Text Available In order to increase productivity, reduce depreciation, and avoid possible accidents in a system such as fuel rods' melting and overpressure, control of temperature changes in the reactor core is an important factor. There are several methods for solving and analysing the stability of point kinetics equations. In most previous analyses, the effects of various factors on the temperature of the reactor core have been ignored. In this work, the effects of various dynamical parameters on the temperature of the reactor core and stability of the system in the presence of temperature feedback reactivity with external reactivity step, ramp and sinusoidal for six groups of delayed neutrons were studied using the method of Lyapunov exponent. The results proved to be in good agreement with other works
Recursive modular modelling methodology for lumped-parameter dynamic systems.
Orsino, Renato Maia Matarazzo
2017-08-01
This paper proposes a novel approach to the modelling of lumped-parameter dynamic systems, based on representing them by hierarchies of mathematical models of increasing complexity instead of a single (complex) model. Exploring the multilevel modularity that these systems typically exhibit, a general recursive modelling methodology is proposed, in order to conciliate the use of the already existing modelling techniques. The general algorithm is based on a fundamental theorem that states the conditions for computing projection operators recursively. Three procedures for these computations are discussed: orthonormalization, use of orthogonal complements and use of generalized inverses. The novel methodology is also applied for the development of a recursive algorithm based on the Udwadia-Kalaba equation, which proves to be identical to the one of a Kalman filter for estimating the state of a static process, given a sequence of noiseless measurements representing the constraints that must be satisfied by the system.
Two-body quantum mechanical problem on spheres
2005-01-01
The quantum mechanical two-body problem with a central interaction on the sphere ${\\bf S}^{n}$ is considered. Using recent results in representation theory an ordinary differential equation for some energy levels is found. For several interactive potentials these energy levels are calculated in explicit form.
Two-body threshold spectral analysis, the critical case
DEFF Research Database (Denmark)
Skibsted, Erik; Wang, Xue Ping
We study in dimension $d\\geq2$ low-energy spectral and scattering asymptotics for two-body $d$-dimensional Schrödinger operators with a radially symmetric potential falling off like $-\\gamma r^{-2},\\;\\gamma>0$. We consider angular momentum sectors, labelled by $l=0,1,\\dots$, for which $\\gamma...
Exact phase space functional for two-body systems
Gracia-Bondía, José M
2010-01-01
The determination of the two-body density functional from its one-body density is achieved for Moshinsky's harmonium model, using a phase-space formulation, thereby resolving its phase dilemma. The corresponding sign rules can equivalently be obtained by minimizing the ground-state energy.
Connection between dynamically derived IMF normalisation and stellar population parameters
McDermid, Richard M; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frederic; Bureau, Martin; Crocker, Alison F; Davies, Roger L; Davis, Timothy A; de Zeeuw, P T; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnovic, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M
2014-01-01
We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the Atlas3D project. We study trends between our dynamically-derived IMF normalisation and absorption line strengths, and interpret these via single stellar population- (SSP-) equivalent ages, abundance ratios (measured as [alpha/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalisation of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of normalisation at a given population parameter. As a result, we find weak IMF-[alpha/Fe] and IMF-age correlations, and no significant IMF-[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalisation via low-mass star demographics inferred through stellar spectra...
Constrained maximum likelihood modal parameter identification applied to structural dynamics
El-Kafafy, Mahmoud; Peeters, Bart; Guillaume, Patrick; De Troyer, Tim
2016-05-01
A new modal parameter estimation method to directly establish modal models of structural dynamic systems satisfying two physically motivated constraints will be presented. The constraints imposed in the identified modal model are the reciprocity of the frequency response functions (FRFs) and the estimation of normal (real) modes. The motivation behind the first constraint (i.e. reciprocity) comes from the fact that modal analysis theory shows that the FRF matrix and therefore the residue matrices are symmetric for non-gyroscopic, non-circulatory, and passive mechanical systems. In other words, such types of systems are expected to obey Maxwell-Betti's reciprocity principle. The second constraint (i.e. real mode shapes) is motivated by the fact that analytical models of structures are assumed to either be undamped or proportional damped. Therefore, normal (real) modes are needed for comparison with these analytical models. The work done in this paper is a further development of a recently introduced modal parameter identification method called ML-MM that enables us to establish modal model that satisfies such motivated constraints. The proposed constrained ML-MM method is applied to two real experimental datasets measured on fully trimmed cars. This type of data is still considered as a significant challenge in modal analysis. The results clearly demonstrate the applicability of the method to real structures with significant non-proportional damping and high modal densities.
Dynamical quantum Hall effect in the parameter space.
Gritsev, V; Polkovnikov, A
2012-04-24
Geometric phases in quantum mechanics play an extraordinary role in broadening our understanding of fundamental significance of geometry in nature. One of the best known examples is the Berry phase [M.V. Berry (1984), Proc. Royal. Soc. London A, 392:45], which naturally emerges in quantum adiabatic evolution. So far the applicability and measurements of the Berry phase were mostly limited to systems of weakly interacting quasi-particles, where interference experiments are feasible. Here we show how one can go beyond this limitation and observe the Berry curvature, and hence the Berry phase, in generic systems as a nonadiabatic response of physical observables to the rate of change of an external parameter. These results can be interpreted as a dynamical quantum Hall effect in a parameter space. The conventional quantum Hall effect is a particular example of the general relation if one views the electric field as a rate of change of the vector potential. We illustrate our findings by analyzing the response of interacting spin chains to a rotating magnetic field. We observe the quantization of this response, which we term the rotational quantum Hall effect.
Oh, Suk Yung; Bae, Young Chan
2010-07-15
The method presented in this paper was developed to predict liquid-liquid equilibria in ternary liquid mixtures by using a combination of a thermodynamic model and molecular dynamics simulations. In general, common classical thermodynamic models have many parameters which are determined by fitting a model with experimental data. This proposed method, however, provides a simple procedure for calculating liquid-liquid equilibria utilizing binary interaction parameters and molecular size parameters determined from molecular dynamics simulations. This method was applied to mixtures containing water, hydrocarbons, alcohols, chlorides, ketones, acids, and other organic liquids over various temperature ranges. The predicted results agree well with the experimental data without the use of adjustable parameters.
Separation of Potentials in the Two-Body Problem
Vasilyev, Andrey
2012-01-01
In contrast to the well-known solution of the two-body problem through the use of the concept of reduced mass, a solution is proposed involving separation of potentials. It is shown that each of the two point bodies moves in its own stationary potential well generated by the other body, and the magnitudes of these potentials are calculated. It is shown also that for each body separately the energy and the angular momentum laws are valid. The knowledge of the potentials in which the bodies are moving permits calculation of the trajectories of each body without resorting to the reduced mass. Key words: mechanics, two-body problem, gravitational potential, virial theorem.
Atlas2bgeneral: Two-body resonance calculator
Gallardo, Tabaré
2016-07-01
For a massless test particle and given a planetary system, Atlas2bgeneral calculates all resonances in a given range of semimajor axes with all the planets taken one by one. Planets are assumed in fixed circular and coplanar orbits and the test particle with arbitrary orbit. A sample input data file to calculate the two-body resonances is available for use with the Fortran77 source code.
Classical and Quantum Two-Body Problem in General Relativity
Maheshwari, Amar; Todorov, Ivan
2016-01-01
The two-body problem in general relativity is reduced to the problem of an effective particle (with an energy-dependent relativistic reduced mass) in an external field. The effective potential is evaluated from the Born diagram of the linearized quantum theory of gravity. It reduces to a Schwarzschild-like potential with two different `Schwarzschild radii'. The results derived in a weak field approximation are expected to be relevant for relativistic velocities.
Analytically optimal parameters of dynamic vibration absorber with negative stiffness
Shen, Yongjun; Peng, Haibo; Li, Xianghong; Yang, Shaopu
2017-02-01
In this paper the optimal parameters of a dynamic vibration absorber (DVA) with negative stiffness is analytically studied. The analytical solution is obtained by Laplace transform method when the primary system is subjected to harmonic excitation. The research shows there are still two fixed points independent of the absorber damping in the amplitude-frequency curve of the primary system when the system contains negative stiffness. Then the optimum frequency ratio and optimum damping ratio are respectively obtained based on the fixed-point theory. A new strategy is proposed to obtain the optimum negative stiffness ratio and make the system remain stable at the same time. At last the control performance of the presented DVA is compared with those of three existing typical DVAs, which were presented by Den Hartog, Ren and Sims respectively. The comparison results in harmonic and random excitation show that the presented DVA in this paper could not only reduce the peak value of the amplitude-frequency curve of the primary system significantly, but also broaden the efficient frequency range of vibration mitigation.
Determining tumor blood flow parameters from dynamic image measurements
Libertini, Jessica M.
2008-11-01
Many recent cancer treatments focus on preventing angiogenesis, the process by which a tumor promotes the growth of large and efficient capillary beds for the increased nourishment required to support the tumor's rapid growth[l]. To measure the efficacy of these treatments in a timely fashion, there is an interest in using data from dynamic sequences of contrast-enhanced medical imaging, such as MRI and CT, to measure blood flow parameters such as perfusion, permeability-surface-area product, and the relative volumes of the plasma and extracellular-extravascular space. Starting with a two compartment model presented by the radiology community[2], this work challenges the application of a simplification to this problem, which was originally developed to model capillary reuptake[3]. While the primary result of this work is the demonstration of the inaccuracy of this simplification, the remainder of the paper is dedicated to presenting alternative methods for calculating the perfusion and plasma volume coefficients. These methods are applied to model data sets based on real patient data, and preliminary results are presented.
Determining tumor blood flow parameters from dynamic image measurements
Energy Technology Data Exchange (ETDEWEB)
Libertini, Jessica M [Division of Applied Mathematics, Brown University, Providence, Rhode Island 02906 (United States)], E-mail: Jessica_Libertini@brown.edu
2008-11-01
Many recent cancer treatments focus on preventing angiogenesis, the process by which a tumor promotes the growth of large and efficient capillary beds for the increased nourishment required to support the tumor's rapid growth. To measure the efficacy of these treatments in a timely fashion, there is an interest in using data from dynamic sequences of contrast-enhanced medical imaging, such as MRI and CT, to measure blood flow parameters such as perfusion, permeability-surface-area product, and the relative volumes of the plasma and extracellular-extravascular space. Starting with a two compartment model presented by the radiology community, this work challenges the application of a simplification to this problem, which was originally developed to model capillary reuptake. While the primary result of this work is the demonstration of the inaccuracy of this simplification, the remainder of the paper is dedicated to presenting alternative methods for calculating the perfusion and plasma volume coefficients. These methods are applied to model data sets based on real patient data, and preliminary results are presented.
On dynamic loads in parallel shaft transmissions. 2: Parameter study
Lin, Edward Hsiang-Hsi; Huston, Ronald L.; Coy, John J.
1987-01-01
Solutions to the governing equations of a spur gear transmission model, developed in NASA TM-100180 (AVSCOM TM-87-C-2), are presented. Factors affecting the dynamic load are identified. It is found that the dynamic load increases with operating speed up to a system natural frequency. At operating speeds beyond the natural frequency the dynamic load decreases dramatically. Also. it is found that the applied load and shaft inertia have little effect on the dynamic load. Damping and friction decrease the dynamic load. Finally, tooth stiffness has a significant effect on dynamic loading; the higher the stiffness, the lower the dynamic loading. Also, the higher the stiffness the higher the rotating speed required for dynamic response.
The two-body random spin ensemble and a new type of quantum phase transition
Energy Technology Data Exchange (ETDEWEB)
Pizorn, Iztok; Prosen, Tomaz [Department of Physics, FMF, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Mossmann, Stefan; Seligman, Thomas H [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, CP 62132 Cuernavaca, Morelos (Mexico)], E-mail: tomaz.prosen@fmf.uni-lj.si
2008-02-15
We study in this paper the properties of a two-body random matrix ensemble for distinguishable spins. We require the ensemble to be invariant under the group of local transformations and analyze a parametrization in terms of the group parameters and the remaining parameters associated with the 'entangling' part of the interaction. We then specialize to a spin chain with nearest-neighbour interactions and numerically find a new type of quantum-phase transition related to the strength of a random external field, i.e. the time-reversal-breaking one-body interaction term.
The two-body random spin ensemble and a new type of quantum phase transition
Pižorn, Iztok; Prosen, Tomaž; Mossmann, Stefan; Seligman, Thomas H.
2008-02-01
We study in this paper the properties of a two-body random matrix ensemble for distinguishable spins. We require the ensemble to be invariant under the group of local transformations and analyze a parametrization in terms of the group parameters and the remaining parameters associated with the 'entangling' part of the interaction. We then specialize to a spin chain with nearest-neighbour interactions and numerically find a new type of quantum-phase transition related to the strength of a random external field, i.e. the time-reversal-breaking one-body interaction term.
Separable approximation method for two-body relativistic scattering
Energy Technology Data Exchange (ETDEWEB)
Tandy, P.C.; Thaler, R.M.
1988-03-01
A method for defining a separable approximation to a given interaction within a two-body relativistic equation, such as the Bethe-Salpeter equation, is presented. The rank-N separable representation given here permits exact reproduction of the T matrix on the mass shell and half off the mass shell at N selected bound state and/or continuum values of the invariant mass. The method employed is a four-space generalization of the separable representation developed for Schroedinger interactions by Ernst, Shakin, and Thaler, supplemented by procedures for dealing with the relativistic spin structure in the case of Dirac particles.
Separable approximation method for two-body relativistic scattering
Tandy, P. C.; Thaler, R. M.
1988-03-01
A method for defining a separable approximation to a given interaction within a two-body relativistic equation, such as the Bethe-Salpeter equation, is presented. The rank-N separable representation given here permits exact reproduction of the T matrix on the mass shell and half off the mass shell at N selected bound state and/or continuum values of the invariant mass. The method employed is a four-space generalization of the separable representation developed for Schrödinger interactions by Ernst, Shakin, and Thaler, supplemented by procedures for dealing with the relativistic spin structure in the case of Dirac particles.
Two-body bound states in quantum electrodynamics. [Rate
Energy Technology Data Exchange (ETDEWEB)
Lepage, G.P.
1978-07-01
Novel formulations of the two-body bound state problem in quantum field theory are examined. While equal in rigor, these have several calculational advantages over the traditional Bethe-Salpeter formalism. In particular there exist exact solutions of the bound state equations for a Coulomb-like interaction in quantum electrodynamics. The corrections to such zeroth-order solutions can be systematically computed in a simple perturbation theory. These methods are illustrated by computing corrections to the orthopositronium decay rate and to the ground state splittings in positronium and muonium.
Two-body bound states & the Bethe-Salpeter equation
Energy Technology Data Exchange (ETDEWEB)
Pichowsky, M. [Argonne National Lab., IL (United States); Kennedy, M. [Univ. of New Hampshire, Durham, NH (United States). Physics Dept.; Strickland, M. [Duke Univ., Durham, NC (United States)
1995-01-18
The Bethe-Salpeter formalism is used to study two-body bound states within a scalar theory: two scalar fields interacting via the exchange of a third massless scalar field. The Schwinger-Dyson equation is derived using functional and diagrammatic techniques, and the Bethe-Salpeter equation is obtained in an analogous way, showing it to be a two-particle generalization of the Schwinger-Dyson equation. The authors also present a numerical method for solving the Bethe-Salpeter equation without three-dimensional reduction. The ground and first excited state masses and wavefunctions are computed within the ladder approximation and space-like form factors are calculated.
Ling-Yuan Hsu; Tsung-Lin Chen
2012-01-01
This paper presents a vehicle dynamics prediction system, which consists of a sensor fusion system and a vehicle parameter identification system. This sensor fusion system can obtain the six degree-of-freedom vehicle dynamics and two road angles without using a vehicle model. The vehicle parameter identification system uses the vehicle dynamics from the sensor fusion system to identify ten vehicle parameters in real time, including vehicle mass, moment of inertial, and road friction coefficie...
Two-body bound state problem and nonsingular scattering equations
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Sandhas, W.
1986-11-01
We present a new momentum space approach to the two-body problem in partial waves. In contrast to the usual momentum space approaches, we treat the bound state case with the help of an inhomogeneous integral equation which possesses solutions for all (negative) energies. The bound state energies and corresponding wave functions are identified by an additional condition. This procedure straightforwardly leads to a nonsingular formulation of the scattering problem in terms of essentially the same equation and thus unifies the descriptions of both energy regimes. We show that the properties of our momentum-space approach can be understood in terms of the so-called regular solution of the Schroedinger equation in position space. The unified description of the bound state and scattering energy regimes in terms of one single, real, and manifestly nonsingular equation allows us to construct an exact representation of the two-body off-shell T matrix in which all the bound state pole and scattering cut information is contained in one single separable term, the remainder being real, nonsingular, and vanishing half on-shell. Such a representation may be of considerable advantage as input in three-body Faddeev-type integral equations. We demonstrate the applicability of our method by calculating bound state and scattering data for the two-nucleon system with the s-wave Malfliet--Tjon III potential.
On the contradiction between the statistical parameters of population dynamics
Korosov Andrey
2012-01-01
A model simulating the dynamics of the field vole (Microtus agrestis) numerosity during one year was built. The purpose of modeling was to reproduce the values of population characteristics, averaged over a long period of field observations. It was found that long-term average population characteristics can not be observed in any one year of simulated population life. A model population with an average long-term dynamics of age structure can not sustain long-term population dynamics. Long-ter...
Varying parameter models to accommodate dynamic promotion effects
Foekens, E.W.; Leeflang, P.S.H.; Wittink, D.R.
1999-01-01
The purpose of this paper is to examine the dynamic effects of sales promotions. We create dynamic brand sales models (for weekly store-level scanner data) by relating store intercepts and a brand's own price elasticity to a measure of the cumulated previous price discounts - amount and time - for t
Varying parameter models to accommodate dynamic promotion effects
Foekens, E.W.; Leeflang, P.S.H.; Wittink, D.R.
1999-01-01
The purpose of this paper is to examine the dynamic effects of sales promotions. We create dynamic brand sales models (for weekly store-level scanner data) by relating store intercepts and a brand's own price elasticity to a measure of the cumulated previous price discounts - amount and time - for
Estimation of Physical Parameters in Linear and Nonlinear Dynamic Systems
DEFF Research Database (Denmark)
Knudsen, Morten
and estimation of physical parameters in particular. 2. To apply the new methods for modelling of specific objects, such as loudspeakers, ac- and dc-motors wind turbines and beat exchangers. A reliable quality measure of an obtained parameter estimate is a prerequisite for any reasonable use of the result...
Nonleptonic two-body Bc-meson decays
Naimuddin, Sk.; Kar, Susmita; Priyadarsini, M.; Barik, N.; Dash, P. C.
2012-11-01
We study the exclusive nonleptonic two-body Bc decays within factorization approximation, in the framework of the relativistic independent quark model based on a confining potential in the scalar-vector harmonic form. The relevant weak form factors and branching ratios for different decay modes (Bc→PP,PV,VP) are predicted in reasonable agreement with other quark model predictions. We find that the dominant contribution to the Bc-meson lifetime comes from the Cabibbo-Kobayashi-Masakawa favored c¯→s¯, d¯ decay modes, and the most promising modes are found to be Bc-→B¯s0π-, Bc-→B¯s0ρ- and Bc-→B¯s⋆0π- with predicted branching ratios of 12.01, 9.96, and 8.61%, respectively, which might be easily detected at the hadron collider in the near future.
Two-body Dirac equation approach to the deuteron
Energy Technology Data Exchange (ETDEWEB)
Galeao, A.P.; Castilho A, J.A.; Ferreira, P. Leal
1996-06-01
The two-body Dirac (Breit) equation with potentials associated to one-boson-exchanges with cutoff masses is solved for the deuteron and its observables calculated. The 16-component wave-function for the J{sup {pi}} = 1{sup +} state contains four independent radial functions which satisfy a system of four coupled differential equations of firs order. This system is numerically integrated, from infinity towards the origin, by fixing the value of the deuteron binding energy and imposing appropriate boundary conditions at infinity. For the exchange potential of the pion, a mixture of direct plus derivative couplings to the nucleon is considered. We varied the pion-nucleon coupling constant, and the best results of our calculations agree with the lower values recently determined for this constant. The present treatment differs from the more conventional ones in that non-relativistic reductions up to the order c{sup -2} are not used. (author). 20 refs., 1 fig., 2 tabs.
Visualized kinematics code for two-body nuclear reactions
Lee, E. J.; Chae, K. Y.
2016-05-01
The one or few nucleon transfer reaction has been a great tool for investigating the single-particle properties of a nucleus. Both stable and exotic beams are utilized to study transfer reactions in normal and inverse kinematics, respectively. Because many energy levels of the heavy recoil from the two-body nuclear reaction can be populated by using a single beam energy, identifying each populated state, which is not often trivial owing to high level-density of the nucleus, is essential. For identification of the energy levels, a visualized kinematics code called VISKIN has been developed by utilizing the Java programming language. The development procedure, usage, and application of the VISKIN is reported.
A search for two body muon decay signals
Bayes, R; Davydov, Yu I; Depommier, P; Faszer, W; Fujiwara, M C; Gagliardi, C A; Gaponenko, A; Gill, D R; Grossheim, A; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hillairet, A; Hu, J; Koetke, D D; MacDonald, R P; Marshall, G M; Mathie, E L; Mischke, R E; Olchanski, K; Olin, A; Openshaw, R; Poutissou, J -M; Poutissou, R; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Tribble, R E
2014-01-01
Lepton family number violation is tested by searching for $\\mu^+\\to e^+X^0$ decays among the 5.8$\\times 10^8$ positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive $X^0$ bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic $\\mu^+\\to e^+X^0$ decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order $10^{-5}$\\ are obtained for boson masses of 10 - 80 MeV/c$^2$ and different asymmetries. For lighter bosons the asymmetry dependence is much stronger and the branching ratio limit varies up to $5.8 \\times 10^{-5}$. This is the first study that explicitly evaluates the limits for anisotropic two body muon decays.
Orbit Determination with the two-body Integrals. II
Gronchi, Giovanni F; Dimare, Linda
2011-01-01
The first integrals of the Kepler problem are used to compute preliminary orbits starting from two short observed arcs of a celestial body, which may be obtained either by optical or radar observations. We write polynomial equations for this problem, that we can solve using the powerful tools of computational Algebra. An algorithm to decide if the linkage of two short arcs is successful, i.e. if they belong to the same observed body, is proposed and tested numerically. In this paper we continue the research started in [Gronchi, Dimare, Milani, 'Orbit determination with the two-body intergrals', CMDA (2010) 107/3, 299-318], where the angular momentum and the energy integrals were used. A suitable component of the Laplace-Lenz vector in place of the energy turns out to be convenient, in fact the degree of the resulting system is reduced to less than half.
Loschmidt echoes in two-body random matrix ensembles
Pižorn, Iztok; Prosen, Tomaž; Seligman, Thomas H.
2007-07-01
Fidelity decay is studied for quantum many-body systems with a dominant independent particle Hamiltonian resulting, e.g., from a mean field theory with a weak two-body interaction. The diagonal terms of the interaction are included in the unperturbed Hamiltonian, while the off-diagonal terms constitute the perturbation that distorts the echo. We give the linear response solution for this problem in a random matrix framework. While the ensemble average shows no surprising behavior, we find that the typical ensemble member as represented by the median displays a very slow fidelity decay known as “freeze.” Numerical calculations confirm this result and show that the ground state even on average displays the freeze. This may contribute to explanation of the “unreasonable” success of mean field theories.
Díaz-Rodríguez, Miguel; Valera, Angel; Page, Alvaro; Besa, Antonio; Mata, Vicente
2016-05-01
Accurate knowledge of body segment inertia parameters (BSIP) improves the assessment of dynamic analysis based on biomechanical models, which is of paramount importance in fields such as sport activities or impact crash test. Early approaches for BSIP identification rely on the experiments conducted on cadavers or through imaging techniques conducted on living subjects. Recent approaches for BSIP identification rely on inverse dynamic modeling. However, most of the approaches are focused on the entire body, and verification of BSIP for dynamic analysis for distal segment or chain of segments, which has proven to be of significant importance in impact test studies, is rarely established. Previous studies have suggested that BSIP should be obtained by using subject-specific identification techniques. To this end, our paper develops a novel approach for estimating subject-specific BSIP based on static and dynamics identification models (SIM, DIM). We test the validity of SIM and DIM by comparing the results using parameters obtained from a regression model proposed by De Leva (1996, "Adjustments to Zatsiorsky-Seluyanov's Segment Inertia Parameters," J. Biomech., 29(9), pp. 1223-1230). Both SIM and DIM are developed considering robotics formalism. First, the static model allows the mass and center of gravity (COG) to be estimated. Second, the results from the static model are included in the dynamics equation allowing us to estimate the moment of inertia (MOI). As a case study, we applied the approach to evaluate the dynamics modeling of the head complex. Findings provide some insight into the validity not only of the proposed method but also of the application proposed by De Leva (1996, "Adjustments to Zatsiorsky-Seluyanov's Segment Inertia Parameters," J. Biomech., 29(9), pp. 1223-1230) for dynamic modeling of body segments.
Manual of spIds, a software package for parameter identification in dynamic systems
Everaars, C.T.H.; Hemker, P.W.; Stortelder, W.J.H.
1995-01-01
This report contains the manual of spIds, version 1.0, a software package for parameter identification in dynamic systems. SpIdslabel{ab:spIds is an acronym of underline{simulation and underline{parameter underline{identification in underline{dynamic underline {systems. It can be applied on wide var
Lee, Jung Hwan; Lee, Sang-Ho
2016-08-01
To evaluate characteristics of static and dynamic parameters in patients with degenerative flat back (DFB) and to compare degree of their improvement between successful and unsuccessful surgical outcome groups. Forty-seven patients with DFB were included who took whole spine X-ray and three-dimensional motion analysis before and 6 months after corrective surgery. Forty-four subjects were selected as a control group. As static parameters, thoracic kyphosis (TK), thoracolumbar junction (TLJ), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured. As dynamic parameters, maximal and minimal angle of pelvic tilt, lower limb joints, and thoracic and lumbar vertebrae column (dynamic TK and LL) in sagittal plane were obtained. The DFB group showed smaller TK and larger LL, pelvic posterior tilt, hip flexion, knee flexion, and ankle dorsiflexion than the control group. Most of these parameters were significantly corrected by fusion surgery. Dynamic spinal parameters correlated with static spinal parameters. The successful group obtained significant improvement in maximal and minimal dynamic LL than the unsuccessful group. The DFB group showed characteristic lower limb and spinal angles in dynamic and static parameters. Correlation between static and dynamic parameters was found in spinal segment. Dynamic LL was good predictor of successful surgical outcomes.
Regularization of the collision in the electromagnetic two-body problem
Hollander, Efrain Buksman; De Luca, Jayme
2004-12-01
We derive a differential equation that is regular at the collision of two equal-mass bodies with attractive interaction in the relativistic action-at-a-distance electrodynamics. We use the energy constant related to the Poincaré invariance of the theory to define finite variables with finite derivatives at the collision. The collision orbits are calculated numerically using the regular equation adapted in a self-consistent minimization method (a stable numerical method that chooses only nonrunaway solutions). This dynamical system appeared 100 years ago as an example of covariant time-symmetric two-body dynamics and acquired the status of electrodynamics in the 1940s by the works of Dirac, Wheeler, and Feynman. We outline the method with an emphasis on the physics of this complex conservative dynamical system.
Probing SUSY CP Violation in Two-Body Stop Decays at the LHC
Deppisch, Frank
2009-01-01
We study CP asymmetries in two-body decays of top squarks into neutralinos and sleptons at the LHC. These asymmetries are used to probe the CP phases possibly present in the stop and neutralino sector of the Minimal Supersymmetric Standard Model. Taking into account bounds from experimental electric dipole moment searches, we identify areas in the mSUGRA parameter space where CP asymmetries can be sizeable and discuss the feasibility of their observation at the LHC. As a result, potentially detectable CP asymmetries in stop decays at the LHC are found, motivating further detailed experimental studies for probing SUSY CP phases.
Probing SUSY CP violation in two-body stop decays at the LHC
Deppisch, Frank F.; Kittel, Olaf
2009-09-01
We study CP asymmetries in two-body decays of top squarks into neutralinos and sleptons at the LHC. These asymmetries are used to probe the CP phases possibly present in the stop and neutralino sector of the Minimal Supersymmetric Standard Model. Taking into account bounds from experimental electric dipole moment searches, we identify areas in the mSUGRA parameter space where CP asymmetries can be sizeable and discuss the feasibility of their observation at the LHC. As a result, potentially detectable CP asymmetries in stop decays at the LHC are found, motivating further detailed experimental studies for probing SUSY CP phases.
Neutron-deuteron scattering calculations with W-matrix representation of the two-body input
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Januschke, T.; Kerwath, U.; Sandhas, W.
1987-11-01
Employing the W-matrix representation of the partial-wave T matrix introduced by Bartnik, Haberzettl, and Sandhas, we show for the example of the Malfliet-Tjon potentials I and III that the single-term separable part of the W-matrix representation, when used as input in three-nucleon neutron-deuteron scattering calculations, is fully capable of reproducing the exact results obtained by Kloet and Tjon. This approximate two-body input not only satisfies the two-body off-shell unitarity relation but, moreover, it also contains a parameter which may be used in optimizing the three-body data. We present numerical evidence that there exists a variational (minimum) principle for the determination of the three-body binding energy which allows one to choose this parameter also in the absence of an exact reference calculation. Our results for neutron-deuteron scattering show that it is precisely this choice of the parameter which provides optimal scattering data. We conclude that the W-matrix approach, despite its simplicity, is a remarkably efficient tool for high-quality three-nucleon calculations.
Neutron-deuteron scattering calculations with W-matrix representation of the two-body input
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Januschke, T.; Kerwath, U.; Sandhas, W.
1987-05-01
Employing the W-matrix representation of the partial-wave T matrix introduced by Bartnik, Haberzettl, and Sandhas, we show for the example of the Malfliet-Tjon potentials I and III that the single-term separable part of the W-matrix representation, when used as input in three-nucleon neutron-deuteron scattering calculations, is fully capable of reproducing the exact results obtained by Kloet and Tjon. This approximate two-body input not only satisfies the two-body off-shell unitarity relation but, moreover, it also contains a parameter which may be used in optimizing the three-body data. We present numerical evidence that there exists a variational (minimum) principle for the determination of the three-body binding energy which allows one to choose this parameter also in the absence of an exact reference calculation. Our results for neutron-deuteron scattering show that it is precisely this choice of the parameter which provides optimal scattering data. We conclude that the W-matrix approach, despite its simplicity, is a remarkably efficient tool for high-quality three-nucleon calculations.
Generalized Extreme Value distribution parameters as dynamical indicators of Stability
Faranda, Davide; Turchetti, Giorgio; Vaienti, Sandro
2011-01-01
We introduce a new dynamical indicator of stability based on the Extreme Value statistics showing that it provides an insight on the local stability properties of dynamical systems. The indicator perform faster than other based on the iteration of the tangent map since it requires only the evolution of the original systems and, in the chaotic regions, gives further information about the information dimension of the attractor. A numerical validation of the method is presented through the analysis of the motions in a Standard map.
Joint Dynamics Modeling and Parameter Identification for Space Robot Applications
Directory of Open Access Journals (Sweden)
Adenilson R. da Silva
2007-01-01
Full Text Available Long-term mission identification and model validation for in-flight manipulator control system in almost zero gravity with hostile space environment are extremely important for robotic applications. In this paper, a robot joint mathematical model is developed where several nonlinearities have been taken into account. In order to identify all the required system parameters, an integrated identification strategy is derived. This strategy makes use of a robust version of least-squares procedure (LS for getting the initial conditions and a general nonlinear optimization method (MCS—multilevel coordinate search—algorithm to estimate the nonlinear parameters. The approach is applied to the intelligent robot joint (IRJ experiment that was developed at DLR for utilization opportunity on the International Space Station (ISS. The results using real and simulated measurements have shown that the developed algorithm and strategy have remarkable features in identifying all the parameters with good accuracy.
Dynamics of 'abc' and 'qd' constant parameters induction generator model
DEFF Research Database (Denmark)
Fajardo-R, L.A.; Medina, A.; Iov, F.
2009-01-01
In this paper, parametric sensibility effects on dynamics of the induction generator in the presence of local perturbations are investigated. The study is conducted in a 3x2 MW wind park dealing with abc, qd0 and qd reduced order, induction generator model respectively, and with fluxes as state v...
Structural parameter identifiability analysis for dynamic reaction networks
DEFF Research Database (Denmark)
Davidescu, Florin Paul; Jørgensen, Sten Bay
2008-01-01
. The proposed analysis is performed in two phases. The first phase determines the structurally identifiable reaction rates based on reaction network stoichiometry. The second phase assesses the structural parameter identifiability of the specific kinetic rate expressions using a generating series expansion...... method based on Lie derivatives. The proposed systematic two phase methodology is illustrated on a mass action based model for an enzymatically catalyzed reaction pathway network where only a limited set of variables is measured. The methodology clearly pinpoints the structurally identifiable parameters...
Dynamics of soil parameters relevant for humanitarian demining
Energy Technology Data Exchange (ETDEWEB)
Obhodas, Jasmina [Institute Ruder Boskovic, Department of Experimental Physics, Bijenicka c. 54, P.O. Box 180, 10000 Zagreb (Croatia); Vdovic, Neda [Institute Ruder Boskovic, Department of Experimental Physics, Bijenicka c. 54, P.O. Box 180, 10000 Zagreb (Croatia); Valkovic, Vlado [Institute Ruder Boskovic, Department of Experimental Physics, Bijenicka c. 54, P.O. Box 180, 10000 Zagreb (Croatia)]. E-mail: valkovic@irb.hr
2005-12-15
In this paper we analyzed characteristics of 6 different soils from the test field at the Ruder Boskovic Institute. Many soil properties relevant for the performance of humanitarian demining tools strongly depend on water content. This is an effort to understand better the soil moisture variability and to find soil parameters that can predict the water content regarding the weather conditions. Such knowledge will allow to optimize demining operations. To gather the main parameters like field capacity, rate and delay of water infiltration and soil water retention which are all related to soil texture, daily time-series of soil moisture from August to November 2001, where analyzed.
Dynamics of order parameters for globally coupled oscillators
DEFF Research Database (Denmark)
De Monte, Silvia; D'ovidio, Francesco
2002-01-01
The equation of motion for the centroid of globally coupled oscillators with natural frequency mismatch is obtained through a series expansion in order parameters, valid for any population size. In the case of strong coupling and narrow-frequency distribution the first-order expansion (correspond...
Synchronous Generator Model Parameter Estimation Based on Noisy Dynamic Waveforms
Berhausen, Sebastian; Paszek, Stefan
2016-01-01
In recent years, there have occurred system failures in many power systems all over the world. They have resulted in a lack of power supply to a large number of recipients. To minimize the risk of occurrence of power failures, it is necessary to perform multivariate investigations, including simulations, of power system operating conditions. To conduct reliable simulations, the current base of parameters of the models of generating units, containing the models of synchronous generators, is necessary. In the paper, there is presented a method for parameter estimation of a synchronous generator nonlinear model based on the analysis of selected transient waveforms caused by introducing a disturbance (in the form of a pseudorandom signal) in the generator voltage regulation channel. The parameter estimation was performed by minimizing the objective function defined as a mean square error for deviations between the measurement waveforms and the waveforms calculated based on the generator mathematical model. A hybrid algorithm was used for the minimization of the objective function. In the paper, there is described a filter system used for filtering the noisy measurement waveforms. The calculation results of the model of a 44 kW synchronous generator installed on a laboratory stand of the Institute of Electrical Engineering and Computer Science of the Silesian University of Technology are also given. The presented estimation method can be successfully applied to parameter estimation of different models of high-power synchronous generators operating in a power system.
Dynamic Modeling and Parameter Identification of Power Systems
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
@@ The generator, the excitation system, the steam turbine and speed governor, and the load are the so called four key models of power systems. Mathematical modeling and parameter identification for the four key models are of great importance as the basis for designing, operating, and analyzing power systems.
Strong Two--Body Decays of Light Mesons
Ricken, R; Merten, D; Metsch, B C; Ricken, Ralf; Koll, Matthias; Merten, Dirk; Metsch, Bernard C.
2003-01-01
In this paper, we present results on strong two-body decay widths of light $q\\bar q$ mesons calculated in a covariant quark model. The model is based on the Bethe-Salpeter equation in its instantaneous approximation and has already been used for computing the complete meson mass spectrum and many electroweak decay observables. Our approach relies on the use of a phenomenological confinement potential with an appropriate spinorial Dirac structure and 't Hooft's instanton--induced interaction as a residual force for pseudoscalar and scalar mesons. The transition matrix element for the decay of one initial meson into two final mesons is evaluated in lowest order by considering conventional decays via quark loops as well as Zweig rule violating instanton--induced decays generated by the six--quark vertex of 't Hooft's interaction; the latter mechanism only contributes if all mesons in the decay have zero total angular momentum. We show that the interference of both decay mechanisms plays an important role in the ...
Parameter Estimation for Dynamic Model of the Financial System
Directory of Open Access Journals (Sweden)
Veronika Novotná
2015-01-01
Full Text Available Economy can be considered a large, open system which is influenced by fluctuations, both internal and external. Based on non-linear dynamics theory, the dynamic models of a financial system try to provide a new perspective by explaining the complicated behaviour of the system not as a result of external influences or random behaviour, but as a result of the behaviour and trends of the system’s internal structures. The present article analyses a chaotic financial system from the point of view of determining the time delay of the model variables – the interest rate, investment demand, and price index. The theory is briefly explained in the first chapters of the paper and serves as a basis for formulating the relations. This article aims to determine the appropriate length of time delay variables in a dynamic model of the financial system in order to express the real economic situation and respect the effect of the history of factors under consideration. The determination of the delay length is carried out for the time series representing Euro area. The methodology for the determination of the time delay is illustrated by a concrete example.
Institute of Scientific and Technical Information of China (English)
Xu Long; Fei Ge; Lei Wang; Youshi Hong
2009-01-01
This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel (SFT) under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio (BWR), stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SFT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investi-gated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.
Dynamics of soil parameters relevant for humanitarian demining
Obhođaš, Jasmina; Vdović, Neda; Valković, Vlado
2005-12-01
In this paper we analyzed characteristics of 6 different soils from the test field at the Ruđer Bošković Institute. Many soil properties relevant for the performance of humanitarian demining tools strongly depend on water content. This is an effort to understand better the soil moisture variability and to find soil parameters that can predict the water content regarding the weather conditions. Such knowledge will allow to optimize demining operations. To gather the main parameters like field capacity, rate and delay of water infiltration and soil water retention which are all related to soil texture, daily time-series of soil moisture from August to November 2001, where analyzed.
One plus two-body random matrix ensembles with parity: Density of states and parity ratios
Vyas, Manan; Srivastava, P C
2011-01-01
One plus two-body embedded Gaussian orthogonal ensemble of random matrices with parity [EGOE(1+2)-$\\pi$] generated by a chaos producing two-body interaction in the presence of a mean-field, for spinless identical fermion systems, is defined in terms of two mixing parameters and a gap between the positive $(\\pi=+)$ and negative $(\\pi=-)$ parity single particle (sp) states. Numerical calculations are used to demonstrate, using realistic values of the mixing parameters appropriate for some nuclei, that this ensemble generates Gaussian form (with corrections) for fixed parity eigenvalue densities (i.e. state densities). The random matrix model also generates many features in parity ratios of state densities that are similar to those predicted by a method based on the Fermi-gas model for nuclei. We have also obtained a simple formula for the spectral variances defined over fixed-$(m_1,m_2)$ spaces, where $m_1$ is the number of fermions in the $+$ve parity sp states and $m_2$ is the number of fermions in the $-$ve ...
Dynamic parameters of Tb-Dy-Fe giant magnetostrictive alloy
Institute of Scientific and Technical Information of China (English)
白夏冰; 蒋成保
2010-01-01
Tb0.3Dy0.7Fe1.90 oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and compliance co...
Institute of Scientific and Technical Information of China (English)
LIU Zong-Liang; ZHAO Fang; LI Shao-Hua; ZHAO Mei-Shan; CHEN Chang-Yong
2008-01-01
This paper is concerned with the determination of a unique scaling parameter in complex scaling analysis and with accurate calculation of dynamics resonances. In the preceding paper we have presented a theoretical analysis and provided a formalism for dynamical resonance calculations. In this paper we present accurate numerical results for two non-trivial dynamical processes, namely, models of diatomie molecular predissoeiation and of barrier potential scattering for resonances. The results presented in this paper confirm our theoretical analysis, remove a theoretical ambiguity on determination of the complex scaling parameter, and provide an improved understanding for dynamical resonance calculations in rigged Hilbert space.
Comparative study of static and dynamic parameters of rock for the Xishan Rock Cliff Statue
Institute of Scientific and Technical Information of China (English)
Jin JIANG; Jin-zhong SUN
2011-01-01
Ultrasonic wave testing was applied to investigate the quality and weathering status of rock specimens obtained in two borings situated in the Xishan Buddha rock slope in Taiyuan,China.This paper pays special attention to the distribution of bulk density,dynamic parameters and static parameters of rock specimens as well as the relationship between static and dynamic parameters.The results illustrate that the distribution of both parameters is identical along the depth of two drilled holes in the rock slope.When the hole depth increases,the density of rock mass,saturated compression strength and static elastic modulus,dynamic elastic modulus and wave velocity also show increase tendency.The weathering degree in the rock mass ranging from the surface of cliffto the depth of 2.5 m is the highest while the rock mass is unsalted and more rigid when the depth is larger than 3.0 m.The relationship between dynamic elastic modulus,sonic wave velocity and horizontal depth indicates that dynamic elastic modulus is more sensitive than sonic wave velocity.Conversely,by comparing quantity relationship between static elastic modulus and sonic wave velocity,it is found that the composition of rock has a great influence on the relationship between static and dynamic parameters,that is,inequality of rock composition will lead to dispersion and abnormality of the distribution of static and dynamic parameters.
On identification of dynamic system parameters from experimental data
CSIR Research Space (South Africa)
Shatalov, M
2007-08-01
Full Text Available -linear differen- tial equations frequently used to describe the dynamics of biological systems in which two species interact. They were proposed independently by Alfred J. Lotka [1] and Vito Volterra in 1926 [2]. This system can be written in the form x′1(t...) = x1 (a11 − a12x2) x′2(t) = x2 (ηa12x1 − a22) When solved for x1 and x2 the above system of equations yields x1 = 0, x1 = 0 and 1 x1 = a22 ηa12 , x1 = a11 a12 hence there are two equilibria. The solution in the neighborhood of the first...
Dynamics of biochemical parameters of blood serum in kidney injuries
Directory of Open Access Journals (Sweden)
Y. L. Podgainiy
2014-12-01
Full Text Available Aim. Annually injuries of varying severity are registered in more than 4,5 million people (up to 10% of the population in Ukraine; renal injury in polytrauma is detected in 26,4% of cases and takes 2 – 3 place of injury of the abdominal cavity and retroperitoneal space. In order to study the kidney function and other vital organs systems 108 patients were examined. Methods and results. Laboratory methods (clinical and biochemical parameters of blood and urine tests, ultrasound and CT scans of the kidneys and abdominal organs were used. Conclusion. It was established that polytrauma often occurs in males (73,5% of middle-age. 42% of patients presented renal function violation - nitrogen excretion and 84% of patients had activated blood coagulation in the first 7 – 10 days of injury.
Weakly nonlinear dynamics and the σ{sub 8} parameter
Energy Technology Data Exchange (ETDEWEB)
Juszkiewicz, Roman [Department of Physics and Astronomy, Zielona Góra University, Lubuska 2, 65-265 Zielona Góra (Poland); Feldman, Hume A. [Department of Physics and Astronomy, University of Kansas, Lawrence KS 66045 (United States); Fry, J.N. [Department of Physics, University of Florida, Gainesville FL 32611-8440 (United States); Jaffe, Andrew H., E-mail: roman@camk.edu.pl, E-mail: feldman@ku.edu, E-mail: fry@phys.ufl.edu, E-mail: a.jaffe@imperial.ac.uk [Astrophysics, Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)
2010-02-01
The amplitude of cosmological density fluctuations, σ{sub 8}, has been studied and estimated by analysing many cosmological observations. The values of the estimates vary considerably between the various probes. However, different estimators probe the value of σ{sub 8} in different cosmological scales and do not take into account the nonlinear evolution of the parameter at late times. We show that estimates of the amplitude of cosmological density fluctuations derived from cosmic flows are systematically higher than those inferred at early epochs from the CMB because of nonlinear evolution at later times. We discuss the past and future evolution of linear and nonlinear perturbations, derive corrections to the value of σ{sub 8} and compare amplitudes after accounting for these differences.
Two body scattering length of Yukawa model on a lattice
De Soto, F; Roiesnel, C; Boucaud, P; Leroy, J P; Pène, O; Boucaud, Ph.
2007-01-01
The extraction of scattering parameters from Euclidean simulations of a Yukawa model in a finite volume with periodic boundary conditions is analyzed both in non relativistic quantum mechanics and in quantum field theory.
A genetic algorithm for dynamic parameters reverse deduction of integrated anchorage system
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In the analysis of the system of anchoring bar and wall rock in small strain and longitudinal vibration dynamic response, the influence of the cement grouting as well as the rock layer on the anchor bar can be evaluated as the two kinds of parameters: the dynamic stiffness and the damp, which are the vital reference of the anchorage quality. Based on the analytic solution to the dynamic equation of the integrated anchor bar, the new approach which combines genetic algorithm and the toolbox of Matlab is applied to solve the problem of multi-parameters reverse deduction for integrated anchorage system in dynamic testing. Using the traits of the self-organizing, self-adapting and the fast convergence speed of the genetic algorithm, the optimum of all possible solutions to dynamic parameters is obtained by calculating the project instances. Examples show that the method presented in this paper is effective and reliable.
Charmless hadronic two-body decays of Bs mesons
Chen, Yaw-Hwang; Cheng, Hai-Yang; Tseng, B.
1999-04-01
Two-body charmless nonleptonic decays of the Bs meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients are μ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of Neffc(LL) and Neffc(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Branching ratios of Bs-->PP,PV,VV decays (P: pseudoscalar meson, V: vector meson) are calculated as a function of Neffc(LR) with two different considerations for Neffc(LL): (a) Neffc(LL) being fixed at the value of 2 and (b) Neffc(LL)=Neffc(LR). Tree and penguin transitions are classified into six different classes. We find the following. (i) The electroweak penguin contributions account for about 85% [for Neffc(LL)=2] of the decay rates of Bs-->ηπ, η'π, ηρ, η'ρ, φπ, φρ, which receive contributions only from tree and electroweak penguin diagrams; a measurement of them will provide a clean determination of the electroweak penguin coefficient a9. (ii) Electroweak penguin corrections to Bs-->ωη('),φη,ωφ,K(*)φ,φφ are in general as significant as QCD penguin effects and even play a dominant role; their decay rates depend strongly on Neffc(LR). (iii) The branching ratio of Bs-->ηη', the analogue of Bd-->η'K, is of order 2×10-5, which is only slightly larger than that of η'η',K*+ρ-,K+K-,K0K¯0 decay modes. (iv) The contribution from the η' charm content is important for Bs-->η'η', but less significant for Bs-->ηη'. (v) The decay rates for the final states K+(*)K-(*) follow the pattern Γ(B¯s-->K+K-)>Γ(B¯s-->K+K*-)>~Γ(B¯s-->K*+K*-)>Γ(B¯s-->K+*K-) and likewise for K0(*)K¯0(*), as a consequence of various interference effects between the penguin amplitudes governed by the effective QCD penguin coefficients a4 and a6.
Rene de Jesus Romero-Troncoso; Gilberto Herrera-Ruiz; Roque Alfredo Osornio-Rios; Luis Morales-Velazquez; Carlos Rodriguez-Donate
2010-01-01
Intelligent robotics demands the integration of smart sensors that allow the controller to efficiently measure physical quantities. Industrial manipulator robots require a constant monitoring of several parameters such as motion dynamics, inclination, and vibration. This work presents a novel smart sensor to estimate motion dynamics, inclination, and vibration parameters on industrial manipulator robot links based on two primary sensors: an encoder and a triaxial accelerometer. The proposed s...
Experimental determination of dynamic parameters of an industrial robot
Banas, W.; Cwikła, G.; Foit, K.; Gwiazda, A.; Monica, Z.; Sekala, A.
2017-08-01
In an industry increasingly used are industrial robots. Commonly used are two basic methods of programming, on-line programming and off-line programming. In both cases, the programming consists in getting to the selected points record this position, and set the order of movement of the robot, and the introduction of logical tests. Such a program is easy to write, and it is suitable for most industrial applications. Especially when the process is known, respectively slow and unchanging. In this case, the program is being prepared for a universal model of the robot with the appropriate geometry and are checked only collisions. Is not taken into account the dynamics of the robot and how it will really behave while in motion. For this reason, the robot programmed to be tested at a reduced speed, which is raised gradually to the final value. Depending on the complexity of the move and the proximity of the elements it takes a lot of time. It is easy to notice that the robot at different speeds have different trajectories and behaves differently.
A detailed study of nonperturbative solutions of two-body Dirac equations
Energy Technology Data Exchange (ETDEWEB)
Crater, H.W.; Becker, R.L.; Wong, C.Y.; Van Alstine, P.
1992-12-01
In quark model calculations of the meson spectrums fully covariant two-body Dirac equations dictated by Dirac's relativistic constraint mechanics gave a good fit to the entire meson mass spectrum for light quark mesons as well as heavy quark mesons with constituent world scalar and vector potentials depending on just one or two parameters. In this paper, we investigate the properties of these equations that made them work so well by solving them numerically for quantum electrodynamics (QED) and related field theories. The constraint formalism generates a relativistic quantum mechanics defined by two coupled Dirac equations on a sixteen component wave function which contain Lorentz covariant constituent potentials that are initially undetermined. An exact Pauli reduction leads to a second order relativistic Schroedinger-like equation for a reduced eight component wave function determined by an effective interaction -- the quasipotential. We first determine perturbatively to lowest order the relativistic quasipotential for the Schroedinger-like equation by comparing that form with one derived from the Bethe-Salpeter equation. Insertion of this perturbative information into the minimal interaction structures of the two-body Dirac equations then completely determines their interaction structures. Then we give a procedure for constructing the full sixteen component solution to our coupled first-order Dirac equations from a solution of the second order equation for the reduced wave function. Next, we show that a perturbative treatment of these equations yields the standard spectral results for QED and related interactions.
Lukasevich, V. I.; Kramarov, S. O.; Sokolov, Sergey V.
2015-01-01
It is solved a problem of a posteriori estimation of dynamically modified parameters of angular movement of the object by satellite measurements. There are shown advantages of application of the methods of stochastic non-linear dynamic filtration before single-stage measurements. It is represented an example, showing efficiency of proposed approach.
Qi, Wei; Zhang, Chi; Fu, Guangtao; Zhou, Huicheng
2016-02-01
It is widely recognized that optimization algorithm parameters have significant impacts on algorithm performance, but quantifying the influence is very complex and difficult due to high computational demands and dynamic nature of search parameters. The overall aim of this paper is to develop a global sensitivity analysis based framework to dynamically quantify the individual and interactive influence of algorithm parameters on algorithm performance. A variance decomposition sensitivity analysis method, Analysis of Variance (ANOVA), is used for sensitivity quantification, because it is capable of handling small samples and more computationally efficient compared with other approaches. The Shuffled Complex Evolution method developed at the University of Arizona algorithm (SCE-UA) is selected as an optimization algorithm for investigation, and two criteria, i.e., convergence speed and success rate, are used to measure the performance of SCE-UA. Results show the proposed framework can effectively reveal the dynamic sensitivity of algorithm parameters in the search processes, including individual influences of parameters and their interactive impacts. Interactions between algorithm parameters have significant impacts on SCE-UA performance, which has not been reported in previous research. The proposed framework provides a means to understand the dynamics of algorithm parameter influence, and highlights the significance of considering interactive parameter influence to improve algorithm performance in the search processes.
Sun, T T; Liu, W H; Zhang, Y Q; Li, L H; Wang, R; Ye, Y Y
2017-08-01
Objective: To explore the differential between the value of dynamic contrast-enhanced MRI quantitative pharmacokinetic parameters and relative pharmacokinetic quantitative parameters in breast lesions. Methods: Retrospective analysis of 255 patients(262 breast lesions) who was obtained by clinical palpation , ultrasound or full-field digital mammography , and then all lessions were pathologically confirmed in Zhongda Hospital, Southeast University from May 2012 to May 2016. A 3.0 T MRI scanner was used to obtain the quantitative MR pharmacokinetic parameters: volume transfer constant (K(trans)), exchange rate constant (k(ep))and extravascular extracellular volume fraction (V(e)). And measured the quantitative pharmacokinetic parameters of normal glands tissues which on the same side of the same level of the lesions; and then calculated the value of relative pharmacokinetic parameters: rK(rans)、rk(ep) and rV(e).To explore the diagnostic value of two pharmacokinetic parameters in differential diagnosis of benign and malignant breast lesions using receiver operating curves and model of logistic regression. Results: (1)There were significant differences between benign lesions and malignant lesions in K(trans) and k(ep) (t=15.489, 15.022, respectively, P0.05). The areas under the ROC curve(AUC)of K(trans), k(ep) and V(e) between malignant and benign lesions were 0.933, 0.948 and 0.387, the sensitivity of K(trans), k(ep) and V(e) were 77.1%, 85.0%, 51.0% , and the specificity of K(trans), k(ep) and V(e) were 96.3%, 93.6%, 60.8% for the differential diagnosis of breast lesions if taken the maximum Youden's index as cut-off. (2)There were significant differences between benign lesions and malignant lesions in rK(trans), rk(ep) and rV(e) (t=14.177, 11.726, 2.477, respectively, Pquantitative pharmacokinetic parameters and the prediction probability of relative quantitative pharmacokinetic parameters(Z=0.867, P=0.195). Conclusion: There was no significant difference between
Identification of Dynamic Parameters Based on Pseudo-Parallel Ant Colony Optimization Algorithm
Institute of Scientific and Technical Information of China (English)
ZHAO Feng-yao; MA Zhen-yue; ZHANG Yun-liang
2007-01-01
For the parameter identification of dynamic problems, a pseudo-parallel ant colony optimization (PPACO) algorithm based on graph-based ant system (AS) was introduced. On the platform of ANSYS dynamic analysis, the PPACO algorithm was applied to the identification of dynamic parameters successfully. Using simulated data of forces and displacements, elastic modulus E and damping ratio ξ was identified for a designed 3D finite element model, and the detailed identification step was given. Mathematical example and simulation example show that the proposed method has higher precision, faster convergence speed and stronger antinoise ability compared with the standard genetic algorithm and the ant colony optimization (ACO) algorithms.
Feasibility of a single-parameter description of equilibrium viscous liquid dynamics
DEFF Research Database (Denmark)
Pedersen, Ulf Rørbæk; Christensen, Tage Emil; Schrøder, Thomas
2008-01-01
Molecular dynamics results for the dynamic Prigogine-Defay ratio are presented for two glass-forming liquids, thus evaluating the experimentally relevant quantity for testing whether metastable-equilibrium liquid dynamics is described by a single parameter to a good approximation. For the Kob......-Andersen binary Lennard-Jones mixture as well as for an asymmetric dumbbell model liquid, a single-parameter description works quite well. This is confirmed by time-domain results where it is found that energy and pressure fluctuations are strongly correlated on the alpha time scale in the constant...
Directory of Open Access Journals (Sweden)
Rene de Jesus Romero-Troncoso
2010-04-01
Full Text Available Intelligent robotics demands the integration of smart sensors that allow the controller to efficiently measure physical quantities. Industrial manipulator robots require a constant monitoring of several parameters such as motion dynamics, inclination, and vibration. This work presents a novel smart sensor to estimate motion dynamics, inclination, and vibration parameters on industrial manipulator robot links based on two primary sensors: an encoder and a triaxial accelerometer. The proposed smart sensor implements a new methodology based on an oversampling technique, averaging decimation filters, FIR filters, finite differences and linear interpolation to estimate the interest parameters, which are computed online utilizing digital hardware signal processing based on field programmable gate arrays (FPGA.
Rodriguez-Donate, Carlos; Morales-Velazquez, Luis; Osornio-Rios, Roque Alfredo; Herrera-Ruiz, Gilberto; de Jesus Romero-Troncoso, Rene
2010-01-01
Intelligent robotics demands the integration of smart sensors that allow the controller to efficiently measure physical quantities. Industrial manipulator robots require a constant monitoring of several parameters such as motion dynamics, inclination, and vibration. This work presents a novel smart sensor to estimate motion dynamics, inclination, and vibration parameters on industrial manipulator robot links based on two primary sensors: an encoder and a triaxial accelerometer. The proposed smart sensor implements a new methodology based on an oversampling technique, averaging decimation filters, FIR filters, finite differences and linear interpolation to estimate the interest parameters, which are computed online utilizing digital hardware signal processing based on field programmable gate arrays (FPGA).
Hsu, Ling-Yuan; Chen, Tsung-Lin
2012-01-01
This paper presents a vehicle dynamics prediction system, which consists of a sensor fusion system and a vehicle parameter identification system. This sensor fusion system can obtain the six degree-of-freedom vehicle dynamics and two road angles without using a vehicle model. The vehicle parameter identification system uses the vehicle dynamics from the sensor fusion system to identify ten vehicle parameters in real time, including vehicle mass, moment of inertial, and road friction coefficients. With above two systems, the future vehicle dynamics is predicted by using a vehicle dynamics model, obtained from the parameter identification system, to propagate with time the current vehicle state values, obtained from the sensor fusion system. Comparing with most existing literatures in this field, the proposed approach improves the prediction accuracy both by incorporating more vehicle dynamics to the prediction system and by on-line identification to minimize the vehicle modeling errors. Simulation results show that the proposed method successfully predicts the vehicle dynamics in a left-hand turn event and a rollover event. The prediction inaccuracy is 0.51% in a left-hand turn event and 27.3% in a rollover event.
Effect of solar dynamics parameters on the formation of substorm activity
Barkhatov, N. A.; Vorob'ev, V. G.; Revunov, S. E.; Yagodkina, O. I.
2017-05-01
An algorithm for retrieving the AL index dynamics from the parameters of solar-wind plasma and the interplanetary magnetic field (IMF) has been developed. Along with other geoeffective parameters of the solar wind, an integral parameter in the form of the cumulative sum Σ[N* V 2] is used to determine the process of substorm formation. The algorithm is incorporated into a framework developed to retrieve the AL index of an Elman-type artificial neural network (ANN) containing an additional layer of neurons that provides an "internal memory" of the prehistory of the dynamical process to be retrieved. The ANN is trained on data of 70 eight-hour-long time intervals, including the periods of isolated magnetospheric substorms. The efficiency of this approach is demonstrated by numerical neural-network experiments on retrieving the dynamics of the AL index from the of solar wind and IMF parameters during substorms.
Sensitivity analysis and dynamic modification of modal parameter in mechanical transmission system
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Sensitivity analysis is one of the effective methods in the dynamic modification. The sensitivity of the modal parameters such as the natural frequencies and mode shapes in undamped free vibration of mechanical transmission system is analyzed in this paper.In particular,the sensitivities of the modal parameters to physical parameters of shaft system such as the inertia and stiffness are given.A calculation formula for dynamic modification is presented based on the analysis of modal parameter.With a mechanical transmission system as an example, the sensitivities of natural frequencies and modes shape are calculated and analyzed. Furthermore, the dynamic modification is also carried out and a good result is obtained.
Energy Technology Data Exchange (ETDEWEB)
Dinca, Laurian; Aldemir, Tunc; Rizzoni, Giorgio
1999-06-01
A probabilistic approach is presented which can be used for the estimation of system parameters and unmonitored state variables towards model-based fault diagnosis in dynamic systems. The method can be used with any type of input-output model and can accommodate noisy data and/or parameter/modeling uncertainties. The methodology is based on Markovian representation of system dynamics in discretized state space. The example system used for the illustration of the methodology focuses on the intake, fueling, combustion and exhaust components of internal combustion engines. The results show that the methodology is capable of estimating the system parameters and tracking the unmonitored dynamic variables within user-specified magnitude intervals (which may reflect noise in the monitored data, random changes in the parameters or modeling uncertainties in general) within data collection time and hence has potential for on-line implementation.
Institute of Scientific and Technical Information of China (English)
M. Shaban; B. Eghbali
2011-01-01
A low carbon Nb-Ti microalloyed steel was subjected to hot torsion testing over the temperature range 850-1100℃ and strain rates 0.01-1 s-1 to study the influence of deformation conditions on the dynamic recrystallization characteristics of austenite. The results show that dynamic recrystallization occurs more easily with the decrease of strain rate and the increase of deformation temperature. The complete dynamically recrystallized grain size as a function of Zener-Hollomon parameter was established. It was found that dynamically recrystallized grain sizes decrease with increasing strain rate and decreasing deformation temperature. The effect of microalloying elements on peak strain was investigated and the solute drag corrected peak strain was determined. Also, the dynamic recrystallization map of austenite was obtained by using recrystallization critical parameters.
Effects on dynamic characters of antenna structures in satellite induced by disordered parameters
Institute of Scientific and Technical Information of China (English)
Liu Xiangqiu; Wang Cong; Wang Weiyuan; Zou Zhenzhu
2009-01-01
A simplified dynamic model of a dish antenna in satellite is established in this article. The model can be easily used to analyze the dynamic behaviour of the antenna structure. In terms of the simplified model, effects on dynamic characters due to the disorder of parameters are investigated in details. The frequencies calculated by the simplified model accord with those computed by ANSYS. Based on the mode shapes of disordered and perfect structure, the influence law and varying trend of dynamic characters of antenna structures in satellites produced by stiffness and mass of antenna ribs, stiffness of antenna membranes and angles between adjacent ribs, are obtained. The analyses in the paper indicate that the effects by disordered parameters can not be ignored in the dynamic analysis of such structures.
Hierarchical Bayesian methods for estimation of parameters in a longitudinal HIV dynamic system.
Huang, Yangxin; Liu, Dacheng; Wu, Hulin
2006-06-01
HIV dynamics studies have significantly contributed to the understanding of HIV infection and antiviral treatment strategies. But most studies are limited to short-term viral dynamics due to the difficulty of establishing a relationship of antiviral response with multiple treatment factors such as drug exposure and drug susceptibility during long-term treatment. In this article, a mechanism-based dynamic model is proposed for characterizing long-term viral dynamics with antiretroviral therapy, described by a set of nonlinear differential equations without closed-form solutions. In this model we directly incorporate drug concentration, adherence, and drug susceptibility into a function of treatment efficacy, defined as an inhibition rate of virus replication. We investigate a Bayesian approach under the framework of hierarchical Bayesian (mixed-effects) models for estimating unknown dynamic parameters. In particular, interest focuses on estimating individual dynamic parameters. The proposed methods not only help to alleviate the difficulty in parameter identifiability, but also flexibly deal with sparse and unbalanced longitudinal data from individual subjects. For illustration purposes, we present one simulation example to implement the proposed approach and apply the methodology to a data set from an AIDS clinical trial. The basic concept of the longitudinal HIV dynamic systems and the proposed methodologies are generally applicable to any other biomedical dynamic systems.
The Method of Variation of Parameters for Solving a Dynamical System of Relative Motion
Institute of Scientific and Technical Information of China (English)
ZHANG Yi
2011-01-01
The integration method of a dynamical system of relative motion is studied,and the method of variation of parameters for the dynamical equations of relative motion is presented.First,the dynamic equations of relative motion are brought into the frame of generalized Birkhoffian systems and are expressed in the contravariant algebraic form.Second,an auxiliary system is constructed and its complete solution is found.Finally,the variation of parameters is given,and a complete solution of the problem is obtained by taking advantage of the properties of generalized canonical transformations.An example is given to illustrate the application of the results.An important direction in analytical dynamics is to present new and versatile integration methods for a complex mechanical system.The motion of a complex system may include the motion of a carrier,as well as the motion of a carried system relative to the carrier.Whittaker[1] studied the Lagrange equations of a holonomic system subject to uniform rotation constraints.Lur'e studied the dynamics of relative motion ofa holonomic system.[2] Mei took the dynamics of relative motion as a special topic to review and research in his monographs.[3-8] Over the past twenty years,research on the dynamics of relative motion has been fruitful.[3- 24]%The integration method of a dynamical system of relative motion is studied, and the method of variation of parameters for the dynamical equations of relative motion is presented. First, the dynamic equations of relative motion are brought into the frame of generalized Birkhoffan systems and are expressed in the contravariant algebraic form. Second, an auxiliary system is constructed and its complete solution is found. Finally, the variation of parameters is given, and a complete solution of the problem is obtained by taking advantage of the properties of generalized canonical transformations. An example is given to illustrate the application of the results.
Analysis of charmless two-body B decays in factorization-assisted topological-amplitude approach
Energy Technology Data Exchange (ETDEWEB)
Zhou, Si-Hong; Zhang, Qi-An; Lue, Cai-Dian [Institute of High Energy Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physics, Beijing (China); Lyu, Wei-Ran [Renmin University of China, Physics Department, Beijing (China)
2017-02-15
We analyze charmless two-body non-leptonic B decays B → PP, PV under the framework of a factorization-assisted topological-amplitude approach, where P(V) denotes a light pseudoscalar (vector) meson. Compared with the conventional flavor diagram approach, we consider the flavor SU(3) breaking effect assisted by a factorization hypothesis for topological diagram amplitudes of different decay modes, factorizing out the corresponding decay constants and form factors. The non-perturbative parameters of topology diagram magnitudes χ and the strong phase φ are universal; they can be extracted by χ{sup 2} fit from current abundant experimental data of charmless B decays. The number of free parameters and the χ{sup 2} per degree of freedom are both reduced compared with previous analyses. With these best fitted parameters, we predict branching fractions and CP asymmetry parameters of nearly 100 B{sub u,d} and B{sub s} decay modes. The long-standing ππ and πK-CP puzzles are solved simultaneously. (orig.)
Nonparametric Comparison of Two Dynamic Parameter Setting Methods in a Meta-Heuristic Approach
Directory of Open Access Journals (Sweden)
Seyhun HEPDOGAN
2007-10-01
Full Text Available Meta-heuristics are commonly used to solve combinatorial problems in practice. Many approaches provide very good quality solutions in a short amount of computational time; however most meta-heuristics use parameters to tune the performance of the meta-heuristic for particular problems and the selection of these parameters before solving the problem can require much time. This paper investigates the problem of setting parameters using a typical meta-heuristic called Meta-RaPS (Metaheuristic for Randomized Priority Search.. Meta-RaPS is a promising meta-heuristic optimization method that has been applied to different types of combinatorial optimization problems and achieved very good performance compared to other meta-heuristic techniques. To solve a combinatorial problem, Meta-RaPS uses two well-defined stages at each iteration: construction and local search. After a number of iterations, the best solution is reported. Meta-RaPS performance depends on the fine tuning of two main parameters, priority percentage and restriction percentage, which are used during the construction stage. This paper presents two different dynamic parameter setting methods for Meta-RaPS. These dynamic parameter setting approaches tune the parameters while a solution is being found. To compare these two approaches, nonparametric statistic approaches are utilized since the solutions are not normally distributed. Results from both these dynamic parameter setting methods are reported.
Searches for CP violation in two-body charm decays
AUTHOR|(CDS)2073698
2015-01-01
The LHCb experiment recorded data corresponding to an integrated luminosity of 3.0 $fb^{-1}$ during its first run of data taking. These data yield the largest samples of charmed hadrons in the world and are used to search for CP violation in the $D^0$ system. Among the many measurements performed at LHCb, a measurement of the direct CP asymmetry in $D^0 \\rightarrow K_S^0 K_S^0$ decays is presented and is found to be $A_{CP}(D^0 \\rightarrow K_S^0 K_S^0) = (-2.9 \\pm 5.2 \\pm 2.2)\\, \\%, $ where the first uncertainty is statistical and the second systematic. This represents a significant improvement in precision over the previous measurement of this parameter. Measurements of the parameter $A^\\Gamma$, defined as the CP asymmetry of the $D^0$ effective lifetime when decaying to a CP eigenstate, are also presented. Using semi-leptonic b-hadron decays to tag the flavour of the $D^0$ meson at production with the $K^+K^-$ and $\\pi^+\\pi^-$ final states yields $A^\\Gamma(K^+K^-) = (-0.134 \\pm 0.077^{+0.026}_{-0.034})\\, \\%...
Directory of Open Access Journals (Sweden)
Wei Wang
2015-01-01
Full Text Available This paper presented a parameter estimation method based on a coupled hydromechanical model of dynamic compaction and the Pareto multiobjective optimization technique. The hydromechanical model of dynamic compaction is established in the FEM program LS-DYNA. The multiobjective optimization algorithm, Nondominated Sorted Genetic Algorithm (NSGA-IIa, is integrated with the numerical model to identify soil parameters using multiple sources of field data. A field case study is used to demonstrate the capability of the proposed method. The observed pore water pressure and crater depth at early blow of dynamic compaction are simultaneously used to estimate the soil parameters. Robustness of the back estimated parameters is further illustrated by a forward prediction. Results show that the back-analyzed soil parameters can reasonably predict lateral displacements and give generally acceptable predictions of dynamic compaction for an adjacent location. In addition, for prediction of ground response of the dynamic compaction at continuous blows, the prediction based on the second blow is more accurate than the first blow due to the occurrence of the hardening and strengthening of soil during continuous compaction.
Research on Dynamic Parameters of Soil Sites in the Dalian Area
Institute of Scientific and Technical Information of China (English)
Zhang Xiaoping; Li Ya; Liu Yang; Jiang Hua; Zhang Yinlong; Huang Yimo
2012-01-01
In this paper, dynamic soil parameters derived from Dalian area seismic risk assessment reports are collected. In this study, the measurement data is divided into 7 types, i.e. silty clay, muddy silty clay, clay, medium sand, rock fragments, backfill soil and fully- weathered slate. Statistics of the dynamic parameters of these soils are carried out to obtain the mean values of dynamic shear modulus ratio and damping ratio. Typical drill holes are selected to establish dynamic soil models to investigate the seismic response for various cases. The dynamic parameters of the models are taken from the statistical values of this study, the standard values of code 94 (i. e. the dynamic soil parameters for Dalian seismic microzonation), and the recommended values by Yuan Xiaoming et al. (2000) respectively. The calculated results of peak ground acceleration are compared with the response spectral characteristics. The results show that the statistical values are approximate to the values recommended by Yuan Xiaoming, et al. (2000), but different greatly with the standard values in code 94.
Exploratory Study for Continuous-time Parameter Estimation of Ankle Dynamics
Kukreja, Sunil L.; Boyle, Richard D.
2014-01-01
Recently, a parallel pathway model to describe ankle dynamics was proposed. This model provides a relationship between ankle angle and net ankle torque as the sum of a linear and nonlinear contribution. A technique to identify parameters of this model in discrete-time has been developed. However, these parameters are a nonlinear combination of the continuous-time physiology, making insight into the underlying physiology impossible. The stable and accurate estimation of continuous-time parameters is critical for accurate disease modeling, clinical diagnosis, robotic control strategies, development of optimal exercise protocols for longterm space exploration, sports medicine, etc. This paper explores the development of a system identification technique to estimate the continuous-time parameters of ankle dynamics. The effectiveness of this approach is assessed via simulation of a continuous-time model of ankle dynamics with typical parameters found in clinical studies. The results show that although this technique improves estimates, it does not provide robust estimates of continuous-time parameters of ankle dynamics. Due to this we conclude that alternative modeling strategies and more advanced estimation techniques be considered for future work.
Quantifying Key Climate Parameter Uncertainties Using an Earth System Model with a Dynamic 3D Ocean
Olson, R.; Sriver, R. L.; Goes, M. P.; Urban, N.; Matthews, D.; Haran, M.; Keller, K.
2011-12-01
Climate projections hinge critically on uncertain climate model parameters such as climate sensitivity, vertical ocean diffusivity and anthropogenic sulfate aerosol forcings. Climate sensitivity is defined as the equilibrium global mean temperature response to a doubling of atmospheric CO2 concentrations. Vertical ocean diffusivity parameterizes sub-grid scale ocean vertical mixing processes. These parameters are typically estimated using Intermediate Complexity Earth System Models (EMICs) that lack a full 3D representation of the oceans, thereby neglecting the effects of mixing on ocean dynamics and meridional overturning. We improve on these studies by employing an EMIC with a dynamic 3D ocean model to estimate these parameters. We carry out historical climate simulations with the University of Victoria Earth System Climate Model (UVic ESCM) varying parameters that affect climate sensitivity, vertical ocean mixing, and effects of anthropogenic sulfate aerosols. We use a Bayesian approach whereby the likelihood of each parameter combination depends on how well the model simulates surface air temperature and upper ocean heat content. We use a Gaussian process emulator to interpolate the model output to an arbitrary parameter setting. We use Markov Chain Monte Carlo method to estimate the posterior probability distribution function (pdf) of these parameters. We explore the sensitivity of the results to prior assumptions about the parameters. In addition, we estimate the relative skill of different observations to constrain the parameters. We quantify the uncertainty in parameter estimates stemming from climate variability, model and observational errors. We explore the sensitivity of key decision-relevant climate projections to these parameters. We find that climate sensitivity and vertical ocean diffusivity estimates are consistent with previously published results. The climate sensitivity pdf is strongly affected by the prior assumptions, and by the scaling
Model reduction and parameter estimation of non-linear dynamical biochemical reaction networks.
Sun, Xiaodian; Medvedovic, Mario
2016-02-01
Parameter estimation for high dimension complex dynamic system is a hot topic. However, the current statistical model and inference approach is known as a large p small n problem. How to reduce the dimension of the dynamic model and improve the accuracy of estimation is more important. To address this question, the authors take some known parameters and structure of system as priori knowledge and incorporate it into dynamic model. At the same time, they decompose the whole dynamic model into subset network modules, based on different modules, and then they apply different estimation approaches. This technique is called Rao-Blackwellised particle filters decomposition methods. To evaluate the performance of this method, the authors apply it to synthetic data generated from repressilator model and experimental data of the JAK-STAT pathway, but this method can be easily extended to large-scale cases.
Institute of Scientific and Technical Information of China (English)
ZHANG Jian; YE Jian-shu; ZHAO Xin-ming
2007-01-01
The finite strip controlling equation of pinned curve box was deduced on basis of Novozhilov theory and with flexibility method, and the problem of continuous curve box was resolved. Dynamic Bayesian error function of displacement parameters of continuous curve box was found. The corresponding formulas of dynamic Bayesian expectation and variance were derived. After the method of solving the automatic search of step length was put forward, the optimization estimation computing formulas were also obtained by adapting conjugate gradient method. Then the steps of dynamic Bayesian estimation were given in detail. Through analysis of a classic example, the criterion of judging the precision of the known information is gained as well as some other important conclusions about dynamic Bayesian stochastic estimation of displacement parameters of continuous curve box.
Energy Technology Data Exchange (ETDEWEB)
Wang, Gangsheng [ORNL; Post, Wilfred M [ORNL; Mayes, Melanie [ORNL
2013-01-01
We developed a Microbial-ENzyme-mediated Decomposition (MEND) model, based on the Michaelis-Menten kinetics, that describes the dynamics of physically defined pools of soil organic matter (SOC). These include particulate, mineral-associated, dissolved organic matter (POC, MOC, and DOC, respectively), microbial biomass, and associated exoenzymes. The ranges and/or distributions of parameters were determined by both analytical steady-state and dynamic analyses with SOC data from the literature. We used an improved multi-objective parameter sensitivity analysis (MOPSA) to identify the most important parameters for the full model: maintenance of microbial biomass, turnover and synthesis of enzymes, and carbon use efficiency (CUE). The model predicted an increase of 2 C (baseline temperature =12 C) caused the pools of POC-Cellulose, MOC, and total SOC to increase with dynamic CUE and decrease with constant CUE, as indicated by the 50% confidence intervals. Regardless of dynamic or constant CUE, the pool sizes of POC, MOC, and total SOC varied from 8% to 8% under +2 C. The scenario analysis using a single parameter set indicates that higher temperature with dynamic CUE might result in greater net increases in both POC-Cellulose and MOC pools. Different dynamics of various SOC pools reflected the catalytic functions of specific enzymes targeting specific substrates and the interactions between microbes, enzymes, and SOC. With the feasible parameter values estimated in this study, models incorporating fundamental principles of microbial-enzyme dynamics can lead to simulation results qualitatively different from traditional models with fast/slow/passive pools.
Multi-parameter numerical simulation of dynamic monitoring of rock deformation in deep mining
Institute of Scientific and Technical Information of China (English)
Li Juanjuan; Hu Mingshun; Ding Enjie; Kong Wei; Pan Dongming; Chen Shenen
2016-01-01
The level of deformation development of surrounding rocks is a vital predictor to evaluate impending coal mine disasters and it is important to establish accurate measurements of the deformed status to ensure coal mine safety. Traditional deformation monitoring methods are mostly based on single parameter, in this paper, multiple approaches are integrated: firstly, both electric and elastic models are established, from which electric field distribution and seismic wave recording are calculated and finally, the resistivity profiles and source position information are determined using inversion methods, from which then the deformation and failure of mine floor are evaluated. According to the inversion results of both electric and seismic field signals, multiple-parameter dynamic monitoring of surrounding rock deformation in deep mine can be performed. The methodology is validated using numerical simulation results which shows that the multi-parameter dynamic monitoring methods have better results for surrounding rock deformation in deep mine monitoring than single parameter methods.
Dynamic State Estimation and Parameter Calibration of DFIG based on Ensemble Kalman Filter
Energy Technology Data Exchange (ETDEWEB)
Fan, Rui; Huang, Zhenyu; Wang, Shaobu; Diao, Ruisheng; Meng, Da
2015-07-30
With the growing interest in the application of wind energy, doubly fed induction generator (DFIG) plays an essential role in the industry nowadays. To deal with the increasing stochastic variations introduced by intermittent wind resource and responsive loads, dynamic state estimation (DSE) are introduced in any power system associated with DFIGs. However, sometimes this dynamic analysis canould not work because the parameters of DFIGs are not accurate enough. To solve the problem, an ensemble Kalman filter (EnKF) method is proposed for the state estimation and parameter calibration tasks. In this paper, a DFIG is modeled and implemented with the EnKF method. Sensitivity analysis is demonstrated regarding the measurement noise, initial state errors and parameter errors. The results indicate this EnKF method has a robust performance on the state estimation and parameter calibration of DFIGs.
Sievers, Sibylle; Nass, Paul; Serrano-Guisan, Santiago; Pasquale, Massimo; Schumacher, Hans Werner
2013-01-01
We investigate an inductive probe head suitable for non-invasive characterization of the magnetostatic and dynamic parameters of magnetic thin films and multilayers on the wafer scale. The probe is based on a planar waveguide with rearward high frequency connectors that can be brought in close contact to the wafer surface. Inductive characterization of the magnetic material is carried out by vector network analyzer ferromagnetic resonance. Analysis of the field dispersion of the resonance allows the determination of key material parameters such as the saturation magnetization MS or the effective damping parameter Meff. Three waveguide designs are tested. The broadband frequency response is characterized and the suitability for inductive determination of MS and Meff is compared. Integration of such probes in a wafer prober could in the future allow wafer scale in-line testing of magnetostatic and dynamic key material parameters of magnetic thin films and multilayers.
Zhang, Zhihua; Sheng, Zheng; Shi, Hanqing; Fan, Zhiqiang
2016-01-01
Using the RFC technique to estimate refractivity parameters is a complex nonlinear optimization problem. In this paper, an improved cuckoo search (CS) algorithm is proposed to deal with this problem. To enhance the performance of the CS algorithm, a parameter dynamic adaptive operation and crossover operation were integrated into the standard CS (DACS-CO). Rechenberg's 1/5 criteria combined with learning factor were used to control the parameter dynamic adaptive adjusting process. The crossover operation of genetic algorithm was utilized to guarantee the population diversity. The new hybrid algorithm has better local search ability and contributes to superior performance. To verify the ability of the DACS-CO algorithm to estimate atmospheric refractivity parameters, the simulation data and real radar clutter data are both implemented. The numerical experiments demonstrate that the DACS-CO algorithm can provide an effective method for near-real-time estimation of the atmospheric refractivity profile from radar clutter.
Directory of Open Access Journals (Sweden)
Zhihua Zhang
2016-01-01
Full Text Available Using the RFC technique to estimate refractivity parameters is a complex nonlinear optimization problem. In this paper, an improved cuckoo search (CS algorithm is proposed to deal with this problem. To enhance the performance of the CS algorithm, a parameter dynamic adaptive operation and crossover operation were integrated into the standard CS (DACS-CO. Rechenberg’s 1/5 criteria combined with learning factor were used to control the parameter dynamic adaptive adjusting process. The crossover operation of genetic algorithm was utilized to guarantee the population diversity. The new hybrid algorithm has better local search ability and contributes to superior performance. To verify the ability of the DACS-CO algorithm to estimate atmospheric refractivity parameters, the simulation data and real radar clutter data are both implemented. The numerical experiments demonstrate that the DACS-CO algorithm can provide an effective method for near-real-time estimation of the atmospheric refractivity profile from radar clutter.
The application of virtual prototyping methods to determine the dynamic parameters of mobile robot
Kurc, Krzysztof; Szybicki, Dariusz; Burghardt, Andrzej; Muszyńska, Magdalena
2016-04-01
The paper presents methods used to determine the parameters necessary to build a mathematical model of an underwater robot with a crawler drive. The parameters present in the dynamics equation will be determined by means of advanced mechatronic design tools, including: CAD/CAE software andMES modules. The virtual prototyping process is described as well as the various possible uses (design adaptability) depending on the optional accessories added to the vehicle. A mathematical model is presented to show the kinematics and dynamics of the underwater crawler robot, essential for the design stage.
Estimating the parameters of dynamical systems from Big Data using Sequential Monte Carlo samplers
Green, P. L.; Maskell, S.
2017-09-01
In this paper the authors present a method which facilitates computationally efficient parameter estimation of dynamical systems from a continuously growing set of measurement data. It is shown that the proposed method, which utilises Sequential Monte Carlo samplers, is guaranteed to be fully parallelisable (in contrast to Markov chain Monte Carlo methods) and can be applied to a wide variety of scenarios within structural dynamics. Its ability to allow convergence of one's parameter estimates, as more data is analysed, sets it apart from other sequential methods (such as the particle filter).
Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach
Scarsoglio, Stefania; Guala, Andrea; Ridolfi, Luca
2015-01-01
Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.
Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach.
Scarsoglio, S; Camporeale, C; Guala, A; Ridolfi, L
2016-01-01
Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring, the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF, both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.
Variability of dynamic source parameters inferred from kinematic models of past earthquakes
Causse, M.
2013-12-24
We analyse the scaling and distribution of average dynamic source properties (fracture energy, static, dynamic and apparent stress drops) using 31 kinematic inversion models from 21 crustal earthquakes. Shear-stress histories are computed by solving the elastodynamic equations while imposing the slip velocity of a kinematic source model as a boundary condition on the fault plane. This is achieved using a 3-D finite difference method in which the rupture kinematics are modelled with the staggered-grid-split-node fault representation method of Dalguer & Day. Dynamic parameters are then estimated from the calculated stress-slip curves and averaged over the fault plane. Our results indicate that fracture energy, static, dynamic and apparent stress drops tend to increase with magnitude. The epistemic uncertainty due to uncertainties in kinematic inversions remains small (ϕ ∼ 0.1 in log10 units), showing that kinematic source models provide robust information to analyse the distribution of average dynamic source parameters. The proposed scaling relations may be useful to constrain friction law parameters in spontaneous dynamic rupture calculations for earthquake source studies, and physics-based near-source ground-motion prediction for seismic hazard and risk mitigation.
Use of PSO in Parameter Estimation of Robot Dynamics; Part Two: Robustness
Jahandideh, Hossein; Namvar, Mehrzad
2012-01-01
In this paper, we analyze the robustness of the PSO-based approach to parameter estimation of robot dynamics presented in Part One. We have made attempts to make the PSO method more robust by experimenting with potential cost functions. The simulated system is a cylindrical robot; through simulation, the robot is excited, samples are taken, error is added to the samples, and the noisy samples are used for estimating the robot parameters through the presented method. Comparisons are made with ...
Zang, Xizhe; Liu, Xinyu; Zhu, Yanhe; Zhao, Jie
2016-04-29
The study of human walking patterns mainly focuses on how control affects walking because control schemes are considered to be dominant in human walking. This study proposes that not only fine control schemes but also optimized body segment parameters are responsible for humans' low-energy walking. A passive dynamic walker provides the possibility of analyzing the effect of parameters on walking efficiency because of its ability to walk without any control. Thus, a passive dynamic walking model with a relatively human-like structure was built, and a parameter optimization process based on the gait sensitivity norm was implemented to determine the optimal mechanical parameters by numerical simulation. The results were close to human body parameters, thus indicating that humans can walk under a passive pattern based on their body segment parameters. A quasi-passive walking prototype was built on the basis of the optimization results. Experiments showed that a passive robot with optimized parameters could walk on level ground with only a simple hip actuation. This result implies that humans can walk under a passive pattern based on their body segment parameters with only simple control strategy implying that humans can opt to walk instinctively under a passive pattern.
a Study of the Charged Two-Body Decays of the Neutral D Mesons
Peng, Kuang-Chung (K. C.).
1995-01-01
The charged two-body decays of D^0 mesons produced by 500 GeV/c pi -incident on platium and carbon foil targets at the Fermilab Tagged Particle Laboratory have been analyzed. Three measurements are presented in this thesis: (1) Branching Ratios of Charged Two-body Decays: {Gamma(D^0to K^+K^-)overGamma(D^0to K^-pi^+)}= 0.107+/-0.003 +/-0.003, {Gamma(D^0to pi^+pi^-)over Gamma(D ^0to K^-pi^+)} =0.040 +/-0.002+/-0.002, {Gamma(D^0 to K^+K^-)overGamma(D^0 topi^+pi^-)}=2.65+/-0.14 +/-0.13, and {Gamma(D^0 to K^-pi^-pi^+pi ^+)overGamma(D^0to K^ -pi^+)} =2.19+/-.0.3+/-.0.08; (2) Lifetime Difference: tau_ {KK}=0.414+/-0.012+/-0.014, tau _{Kpi}=0.409+/-0.003+/-0.004, with Deltagamma= {-}0.06 +/-0.15+/-0.15, or the upper limit of Mixing rate as {cal R}_sp {rm mix}{it y}<0.00079 (due to lifetime difference only) at mix 90% confidence level; and (3) CP Asymmetry Parameters: A_sp{CP}{BR}(K^+/- K^mp) = {-}0.018+/-0.054+/-0.012, A_sp{CP}{BR}( pi^+/-pi^mp) = { -}0.053+/-0.093+/-0.029, and A _sp{CP}{BR}(K3pi) - {-}0.018+/-0.023+/-0.002.. All measurements are consistent with most theoretical predictions and world average experimental values.
Research on Dynamic Parameters of Soil Site in the Tianjin Coastal Area
Institute of Scientific and Technical Information of China (English)
Peng Yanju; Lv Yuejun; Qian Haitao
2011-01-01
The Tianjin coastal area is a typical soft soil region, where the soil is a marine deposit of the late Quaternary. The soil dynamic parameters from seismic risk assessment reports are collected, and drilling of 15 holes was carried out to sample the soils and measure their dynamic characteristics. The data was divided into 7 types based on lithology, namely, muddy clay, muddy silty clay, silt, silty clay, clay, silty sand and fine sand. Statistics of the dynamic parameters of these soils are collected to obtain the mean values of dynamic shear modulus ratio and damping ratio at different depths. Then, two typical drill holes are selected to establish the soil dynamic models to investigate the seismic response in different cases. The dynamic seismic responses of soil are calculated using the statistical values of this paper, and the values of Code （1994） and those recommended by Yuan Xiaoming et al. （2000）, respectively. The applicability and pertinence of the statistical value obtained in this paper are demonstrated by the response spectrum shape, peak ground acceleration and response spectral characteristics. The results can be taken as a reference of the soil dynamic value in this area and can be used in the seismic risk assessment of engineering projects.
Sliding mode identifier for parameter uncertain nonlinear dynamic systems with nonlinear input
Institute of Scientific and Technical Information of China (English)
张克勤; 庄开宇; 苏宏业; 褚健; 高红
2002-01-01
This paper presents a sliding mode (SM) based identifier to deal wit h the parameter identification problem for a class of parameter uncertain nonlin ear dynamic systems with input nonlinearity. A sliding mode controller (SMC) is used to ensure the global reaching condition of the sliding mode for the nonline ar system; an identifier is designed to identify the uncertain parameter of the nonlinear system. A numerical example is studied to show the feasibility of the SM controller and the asymptotical convergence of the identifier.
Sliding mode identifier for parameter uncertain nonlinear dynamic systems with nonlinear input
Institute of Scientific and Technical Information of China (English)
张克勤; 庄开宇; 苏宏业; 褚健; 高红
2002-01-01
This paper presents a sliding mode(SM) based identifier to deal with the parameter idenfification problem for a class of parameter uncertain nonlinear dynamic systems with input nonlinearity. A sliding mode controller (SMC) is used to ensure the global reaching condition of the sliding mode for the nonlinear system;an identifier is designed to identify the uncertain parameter of the nonlinear system. A numerical example is studied to show the feasibility of the SM controller and the asymptotical convergence of the identifier.
Energy Technology Data Exchange (ETDEWEB)
Ducoste, J.; Brauer, R.
1999-07-01
Analysis of a computational fluid dynamics (CFD) model for a water treatment plant clearwell was done. Model parameters were analyzed to determine their influence on the effluent-residence time distribution (RTD) function. The study revealed that several model parameters could have significant impact on the shape of the RTD function and consequently raise the level of uncertainty on accurate predictions of clearwell hydraulics. The study also revealed that although the modeler could select a distribution of values for some of the model parameters, most of these values can be ruled out by requiring the difference between the calculated and theoretical hydraulic retention time to within 5% of the theoretical value.
Yang, Cheng-Hsiung; Wu, Cheng-Lin
2014-01-01
An adaptive control scheme is developed to study the generalized adaptive chaos synchronization with uncertain chaotic parameters behavior between two identical chaotic dynamic systems. This generalized adaptive chaos synchronization controller is designed based on Lyapunov stability theory and an analytic expression of the adaptive controller with its update laws of uncertain chaotic parameters is shown. The generalized adaptive synchronization with uncertain parameters between two identical new Lorenz-Stenflo systems is taken as three examples to show the effectiveness of the proposed method. The numerical simulations are shown to verify the results.
DEFF Research Database (Denmark)
Ruano, MV; Ribes, J; de Pauw, DJW
2007-01-01
In this work we address the issue of parameter subset selection within the scope of activated sludge model calibration. To this end, we evaluate two approaches: (i) systems analysis and (ii) experience-based approach. The evaluation has been carried out using a dynamic model (ASM2d) calibrated...... based approaches which excluded them from their analysis. Systems analysis reveals that parameter significance ranking and size of the identifiable parameter subset depend on the information content of data available for calibration. However, it suffers from heavy computational demand. In contrast...
Dunn, M.; Watson, D. K.; Loeser, J. G.
2006-08-01
In this paper, we develop an analytic N-body wave function for identical particles under quantum confinement with a general two-body interaction. A systematic approach to correlation is developed by combining three theoretical methods: dimensional perturbation theory, the FG method of Wilson et. al., and the group theory of the symmetric group. Analytic results are achieved for a completely general interaction potential. Unlike conventional perturbation methods which are applicable only for weakly interacting systems, this analytic approach is applicable to both weakly and strongly interacting systems. This method directly accounts for each two-body interaction, rather than an average interaction so even lowest-order results include beyond-mean-field effects. One major advantage is that N appears as a parameter in the analytical expressions for the energy so results for different N are easy to obtain.
Directory of Open Access Journals (Sweden)
Rutao Luo
Full Text Available Mathematical models based on ordinary differential equations (ODE have had significant impact on understanding HIV disease dynamics and optimizing patient treatment. A model that characterizes the essential disease dynamics can be used for prediction only if the model parameters are identifiable from clinical data. Most previous parameter identification studies for HIV have used sparsely sampled data from the decay phase following the introduction of therapy. In this paper, model parameters are identified from frequently sampled viral-load data taken from ten patients enrolled in the previously published AutoVac HAART interruption study, providing between 69 and 114 viral load measurements from 3-5 phases of viral decay and rebound for each patient. This dataset is considerably larger than those used in previously published parameter estimation studies. Furthermore, the measurements come from two separate experimental conditions, which allows for the direct estimation of drug efficacy and reservoir contribution rates, two parameters that cannot be identified from decay-phase data alone. A Markov-Chain Monte-Carlo method is used to estimate the model parameter values, with initial estimates obtained using nonlinear least-squares methods. The posterior distributions of the parameter estimates are reported and compared for all patients.
A Database of Force-Field Parameters, Dynamics, and Properties of Antimicrobial Compounds
Directory of Open Access Journals (Sweden)
Giuliano Malloci
2015-08-01
Full Text Available We present an on-line database of all-atom force-field parameters and molecular properties of compounds with antimicrobial activity (mostly antibiotics and some beta-lactamase inhibitors. For each compound, we provide the General Amber Force Field parameters for the major species at physiological pH, together with an analysis of properties of interest as extracted from µs-long molecular dynamics simulations in explicit water solution. The properties include number and population of structural clusters, molecular flexibility, hydrophobic and hydrophilic molecular surfaces, the statistics of intraand inter-molecular H-bonds, as well as structural and dynamical properties of solvent molecules within first and second solvation shells. In addition, the database contains several key molecular parameters, such as energy of the frontier molecular orbitals, vibrational properties, rotational constants, atomic partial charges and electric dipole moment, computed by Density Functional Theory. The present database (to our knowledge the first extensive one including dynamical properties is part of a wider project aiming to build-up a database containing structural, physico-chemical and dynamical properties of medicinal compounds using different force-field parameters with increasing level of complexity and reliability. The database is freely accessible at http://www.dsf.unica.it/translocation/db/.
Fisher, Lloyd J; Hoffman, Edward L
1958-01-01
Data from ditching investigations conducted at the Langley Aeronautical Laboratory with dynamic scale models of various airplanes are presented in the form of tables. The effects of design parameters on the ditching characteristics of airplanes, based on scale-model investigations and on reports of full-scale ditchings, are discussed. Various ditching aids are also discussed as a means of improving ditching behavior.
Breathing dynamics based parameter sensitivity analysis of hetero-polymeric DNA
Energy Technology Data Exchange (ETDEWEB)
Talukder, Srijeeta; Sen, Shrabani; Chaudhury, Pinaki, E-mail: pinakc@rediffmail.com [Department of Chemistry, University of Calcutta, 92 A P C Road, Kolkata 700 009 (India); Chakraborti, Prantik; Banik, Suman K., E-mail: skbanik@jcbose.ac.in [Department of Chemistry, Bose Institute, 93/1 A P C Road, Kolkata 700 009 (India); Metzler, Ralf, E-mail: rmetzler@uni-potsdam.de [Institute for Physics and Astronomy, University of Potsdam, D-14476 Potsdam-Golm, Germany and Physics Department, Tampere University of Technology, FI-33101 Tampere (Finland)
2014-03-28
We study the parameter sensitivity of hetero-polymeric DNA within the purview of DNA breathing dynamics. The degree of correlation between the mean bubble size and the model parameters is estimated for this purpose for three different DNA sequences. The analysis leads us to a better understanding of the sequence dependent nature of the breathing dynamics of hetero-polymeric DNA. Out of the 14 model parameters for DNA stability in the statistical Poland-Scheraga approach, the hydrogen bond interaction ε{sub hb}(AT) for an AT base pair and the ring factor ξ turn out to be the most sensitive parameters. In addition, the stacking interaction ε{sub st}(TA-TA) for an TA-TA nearest neighbor pair of base-pairs is found to be the most sensitive one among all stacking interactions. Moreover, we also establish that the nature of stacking interaction has a deciding effect on the DNA breathing dynamics, not the number of times a particular stacking interaction appears in a sequence. We show that the sensitivity analysis can be used as an effective measure to guide a stochastic optimization technique to find the kinetic rate constants related to the dynamics as opposed to the case where the rate constants are measured using the conventional unbiased way of optimization.
Optimal Design of Measurement Programs for the Parameter Identification of Dynamic Systems
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune
1991-01-01
The design of a measurement program devoted to parameter identification of structural dynamic systems is considered. The design problem is formulated as an optimization problem to minimize the total expected cost, i.e. the cost of failure and the cost of the measurement program. All the calculati...
Satoh, Katsuhiko
2013-08-28
The thermodynamic scaling of molecular dynamic properties of rotation and thermodynamic parameters in a nematic phase was investigated by a molecular dynamic simulation using the Gay-Berne potential. A master curve for the relaxation time of flip-flop motion was obtained using thermodynamic scaling, and the dynamic property could be solely expressed as a function of TV(γτ) , where T and V are the temperature and volume, respectively. The scaling parameter γτ was in excellent agreement with the thermodynamic parameter Γ, which is the logarithm of the slope of a line plotted for the temperature and volume at constant P2. This line was fairly linear, and as good as the line for p-azoxyanisole or using the highly ordered small cluster model. The equivalence relation between Γ and γ(τ) was compared with results obtained from the highly ordered small cluster model. The possibility of adapting the molecular model for the thermodynamic scaling of other dynamic rotational properties was also explored. The rotational diffusion constant and rotational viscosity coefficients, which were calculated using established theoretical and experimental expressions, were rescaled onto master curves with the same scaling parameters. The simulation illustrates the universal nature of the equivalence relation for liquid crystals.
Flight dynamics modeling of a small ducted fan aerial vehicle based on parameter identification
Institute of Scientific and Technical Information of China (English)
Wang Zhengjie; Liu Zhijun; Fan Ningjun; Guo Meifang
2013-01-01
This paper presents a simple and useful modeling method to acquire a dynamics model of an aerial vehicle containing unknown parameters using mechanism modeling, and then to design different identification experiments to identify the parameters based on the sources and features of its unknown parameters. Based on the mathematical model of the aerial vehicle acquired by modeling and identification, a design for the structural parameters of the attitude control system is carried out, and the results of the attitude control flaps are verified by simulation experiments and flight tests of the aerial vehicle. Results of the mathematical simulation and flight tests show that the mathematical model acquired using parameter identification is comparatively accurate and of clear mechanics, and can be used as the reference and basis for the structural design.
Energy Technology Data Exchange (ETDEWEB)
Ma Huanfei [Center for Computational Systems Biology, Fudan University, Shanghai 200433 (China)] [School of Computer Science, Fudan University, Shanghai 200433 (China); Lin Wei, E-mail: wlin@fudan.edu.c [Center for Computational Systems Biology, Fudan University, Shanghai 200433 (China)] [School of Mathematical Sciences, Fudan University, Shanghai 200433 (China)] [Key Laboratory of Mathematics for Nonlinear Sciences (Fudan University), Ministry of Education (China)] [CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Sciences, Shanghai 200031 (China)
2009-12-28
The existing adaptive synchronization technique based on the stability theory and invariance principle of dynamical systems, though theoretically proved to be valid for parameters identification in specific models, is always showing slow convergence rate and even failed in practice when the number of parameters becomes large. Here, for parameters update, a novel nonlinear adaptive rule is proposed to accelerate the rate. Its feasibility is validated by analytical arguments as well as by specific parameters identification in the Lotka-Volterra model with multiple species. Two adjustable factors in this rule influence the identification accuracy, which means that a proper choice of these factors leads to an optimal performance of this rule. In addition, a feasible method for avoiding the occurrence of the approximate linear dependence among terms with parameters on the synchronized manifold is also proposed.
Estimation of noise parameters in dynamical system identification with Kalman filters.
Kwasniok, Frank
2012-09-01
A method is proposed for determining dynamical and observational noise parameters in state and parameter identification from time series using Kalman filters. The noise covariances are estimated in a secondary optimization by maximizing the predictive likelihood of the data. The approach is based on internal consistency; for the correct noise parameters, the uncertainty projected by the Kalman filter matches the actual predictive uncertainty. The method is able to disentangle dynamical and observational noise. The algorithm is demonstrated for the linear, extended, and unscented Kalman filters using an Ornstein-Uhlenbeck process, the noise-driven Lorenz system, and van der Pol oscillator as well as a paleoclimatic ice-core record as examples. The approach is also applicable to the ensemble Kalman filter and can be readily extended to non-Gaussian estimation frameworks such as Gaussian-sum filters and particle filters.
Evolutionary Design of Both Topologies and Parameters of a Hybrid Dynamical System
DEFF Research Database (Denmark)
Dupuis, Jean-Francois; Fan, Zhun; Goodman, Erik
2012-01-01
This paper investigates the issue of evolutionary design of open-ended plants for hybrid dynamical systems--i.e. both their topologies and parameters. Hybrid bond graphs are used to represent dynamical systems involving both continuous and discrete system dynamics. Genetic programming, with some...... special mechanisms incorporated, is used as a search tool to explore the open-ended design space of hybrid bond graphs. Combination of these two tools--i.e., hybrid bond graphs (HGBs) and genetic programming (GP)--leads to an approach called HBGGP that can automatically generate viable design candidates...... of hybrid dynamical systems that fulfill predefined design specifications. A comprehensive investigation of a case study of DC-DC converter design demonstrates the feasibility and effectiveness of the HBGGP approach. Important characteristics of the approach are also discussed, with some future research...
Directory of Open Access Journals (Sweden)
Yu-Chi Wang
2015-01-01
Full Text Available This paper presents a unified approach to nonlinear dynamic inversion control algorithm with the parameters for desired dynamics determined by using an eigenvalue assignment method, which may be applied in a very straightforward and convenient way. By using this method, it is not necessary to transform the nonlinear equations into linear equations by feedback linearization before beginning control designs. The applications of this method are not limited to affine nonlinear control systems or limited to minimum phase problems if the eigenvalues of error dynamics are carefully assigned so that the desired dynamics is stable. The control design by using this method is shown to be robust to modeling uncertainties. To validate the theory, the design of a UAV control system is presented as an example. Numerical simulations show the performance of the design to be quite remarkable.
Determining dynamical parameters of the Milky Way Galaxy based on high-accuracy radio astrometry
Honma, Mareki; Nagayama, Takumi; Sakai, Nobuyuki
2015-08-01
In this paper we evaluate how the dynamical structure of the Galaxy can be constrained by high-accuracy VLBI (Very Long Baseline Interferometry) astrometry such as VERA (VLBI Exploration of Radio Astrometry). We generate simulated samples of maser sources which follow the gas motion caused by a spiral or bar potential, with their distribution similar to those currently observed with VERA and VLBA (Very Long Baseline Array). We apply the Markov chain Monte Carlo analyses to the simulated sample sources to determine the dynamical parameter of the models. We show that one can successfully determine the initial model parameters if astrometric results are obtained for a few hundred sources with currently achieved astrometric accuracy. If astrometric data are available from 500 sources, the expected accuracy of R0 and Θ0 is ˜ 1% or higher, and parameters related to the spiral structure can be constrained by an error of 10% or with higher accuracy. We also show that the parameter determination accuracy is basically independent of the locations of resonances such as corotation and/or inner/outer Lindblad resonances. We also discuss the possibility of model selection based on the Bayesian information criterion (BIC), and demonstrate that BIC can be used to discriminate different dynamical models of the Galaxy.
Zhang, Wei-Ya; Li, Yong-Li; Chang, Xiao-Yong; Wang, Nan
2013-09-01
In this paper, the dynamic behavior analysis of the electromechanical coupling characteristics of a flywheel energy storage system (FESS) with a permanent magnet (PM) brushless direct-current (DC) motor (BLDCM) is studied. The Hopf bifurcation theory and nonlinear methods are used to investigate the generation process and mechanism of the coupled dynamic behavior for the average current controlled FESS in the charging mode. First, the universal nonlinear dynamic model of the FESS based on the BLDCM is derived. Then, for a 0.01 kWh/1.6 kW FESS platform in the Key Laboratory of the Smart Grid at Tianjin University, the phase trajectory of the FESS from a stable state towards chaos is presented using numerical and stroboscopic methods, and all dynamic behaviors of the system in this process are captured. The characteristics of the low-frequency oscillation and the mechanism of the Hopf bifurcation are investigated based on the Routh stability criterion and nonlinear dynamic theory. It is shown that the Hopf bifurcation is directly due to the loss of control over the inductor current, which is caused by the system control parameters exceeding certain ranges. This coupling nonlinear process of the FESS affects the stability of the motor running and the efficiency of energy transfer. In this paper, we investigate into the effects of control parameter change on the stability and the stability regions of these parameters based on the averaged-model approach. Furthermore, the effect of the quantization error in the digital control system is considered to modify the stability regions of the control parameters. Finally, these theoretical results are verified through platform experiments.
Parameters in dynamic models of complex traits are containers of missing heritability.
Directory of Open Access Journals (Sweden)
Yunpeng Wang
Full Text Available Polymorphisms identified in genome-wide association studies of human traits rarely explain more than a small proportion of the heritable variation, and improving this situation within the current paradigm appears daunting. Given a well-validated dynamic model of a complex physiological trait, a substantial part of the underlying genetic variation must manifest as variation in model parameters. These parameters are themselves phenotypic traits. By linking whole-cell phenotypic variation to genetic variation in a computational model of a single heart cell, incorporating genotype-to-parameter maps, we show that genome-wide association studies on parameters reveal much more genetic variation than when using higher-level cellular phenotypes. The results suggest that letting such studies be guided by computational physiology may facilitate a causal understanding of the genotype-to-phenotype map of complex traits, with strong implications for the development of phenomics technology.
Evaluation of a new parallel numerical parameter optimization algorithm for a dynamical system
Duran, Ahmet; Tuncel, Mehmet
2016-10-01
It is important to have a scalable parallel numerical parameter optimization algorithm for a dynamical system used in financial applications where time limitation is crucial. We use Message Passing Interface parallel programming and present such a new parallel algorithm for parameter estimation. For example, we apply the algorithm to the asset flow differential equations that have been developed and analyzed since 1989 (see [3-6] and references contained therein). We achieved speed-up for some time series to run up to 512 cores (see [10]). Unlike [10], we consider more extensive financial market situations, for example, in presence of low volatility, high volatility and stock market price at a discount/premium to its net asset value with varying magnitude, in this work. Moreover, we evaluated the convergence of the model parameter vector, the nonlinear least squares error and maximum improvement factor to quantify the success of the optimization process depending on the number of initial parameter vectors.
The role of heterogeneities as a tuning parameter of earthquake dynamics in relation to criticality
Zoeller, G.; Holschneider, M.; Ben-Zion, Y.
2003-12-01
We investigate the influence of spatial heterogeneities on various aspects of seismicity in a single-fault model. The model dynamics is governed by realistic boundary conditions consisting of constant velocity motion of regions around the fault, static/kinetic friction laws, creep with depth-dependent coefficients as in Ben-Zion (JGR 101, 1996), and 3D elastic stress transfer based on the solution of Chinnery (1963). The dynamic rupture is approximated on a continuous time scale using a finite stress propagation velocity (``quasi-dynamic model''). The model produces a ``brittle-ductile'' transition at a depth of about 12.5 km, realistic hypocenter distributions, and other features of seismicity compatible with observations. Ben-Zion et al. (JGR 108, 2003) suggested that the range of size scales in the distribution of strength-stress heterogeneities acts as a tuning parameter of dynamics, and that the evolution of this parameter in large earthquake cycles produces intermittent criticality. Here we test this hypothesis by performing a systematic parameter-space study with different forms of heterogeneities. In particular, we analyse spatial heterogeneities that can be tuned by a single parameter in two distributions: (1) a set of circular asperities with a different stress drop and variable range of radii and (2) spatial heterogeneities with fractal properties and variable fractal dimension. We analyze the influence of the tuning parameter of the heterogeneities on different measures of seismicity and discuss the results in terms of the phase diagram approach of Dahmen et al. (Phys. Rev. E 58, 1998).
Shankaraiah, N.; Dubey, Awadhesh K.; Puri, Sanjay; Shenoy, Subodh R.
2016-12-01
In the conceptual framework of phase ordering after temperature quenches below transition, we consider the underdamped Bales-Gooding-type "momentum conserving" dynamics of a 2D martensitic structural transition from a square-to-rectangle unit cell. The one-component or NOP=1 order parameter is one of the physical strains, and the Landau free energy has a triple well, describing a first-order transition. We numerically study the evolution of the strain-strain correlation, and find that it exhibits dynamical scaling, with a coarsening length L (t ) ˜tα . We find at intermediate and long times that the coarsening exponent sequentially takes on respective values close to α =2 /3 and 1 /2 . For deep quenches, the coarsening can be arrested at long times, with α ≃0 . These exponents are also found in 3D. To understand such behavior, we insert a dynamical-scaling ansatz into the correlation function dynamics to give, at a dominant scaled separation, a nonlinear kinetics of the curvature g (t )≡1 /L (t ) . The curvature solutions have time windows of power-law decays g ˜1 /tα , with exponent values α matching simulations, and manifestly independent of spatial dimension. Applying this curvature-kinetics method to mass-conserving Cahn-Hilliard dynamics for a double-well Landau potential in a scalar NOP=1 order parameter yields exponents α =1 /4 and 1 /3 for intermediate and long times. For vector order parameters with NOP≥2 , the exponents are α =1 /4 only, consistent with previous work. The curvature kinetics method could be useful in extracting coarsening exponents for other phase-ordering dynamics.
A new closed-loop output error method for parameter identification of robot dynamics
Gautier, Maxime; Vandanjon, Pierre-Olivier
2010-01-01
Off-line robot dynamic identification methods are mostly based on the use of the inverse dynamic model, which is linear with respect to the dynamic parameters. This model is sampled while the robot is tracking reference trajectories that excite the system dynamics. This allows using linear least-squares techniques to estimate the parameters. The efficiency of this method has been proved through the experimental identification of many prototypes and industrial robots. However, this method requires the joint force/torque and position measurements and the estimate of the joint velocity and acceleration, through the bandpass filtering of the joint position at high sampling rates. The proposed new method requires only the joint force/torque measurement. It is a closed-loop output error method where the usual joint position output is replaced by the joint force/torque. It is based on a closed-loop simulation of the robot using the direct dynamic model, the same structure of the control law, and the same reference t...
Optimal Input Design for Aircraft Parameter Estimation using Dynamic Programming Principles
Morelli, Eugene A.; Klein, Vladislav
1990-01-01
A new technique was developed for designing optimal flight test inputs for aircraft parameter estimation experiments. The principles of dynamic programming were used for the design in the time domain. This approach made it possible to include realistic practical constraints on the input and output variables. A description of the new approach is presented, followed by an example for a multiple input linear model describing the lateral dynamics of a fighter aircraft. The optimal input designs produced by the new technique demonstrated improved quality and expanded capability relative to the conventional multiple input design method.
Parameter estimation of social forces in pedestrian dynamics models via a probabilistic method.
Corbetta, Alessandro; Muntean, Adrian; Vafayi, Kiamars
2015-04-01
Focusing on a specific crowd dynamics situation, including real life experiments and measurements, our paper targets a twofold aim: (1) we present a Bayesian probabilistic method to estimate the value and the uncertainty (in the form of a probability density function) of parameters in crowd dynamic models from the experimental data; and (2) we introduce a fitness measure for the models to classify a couple of model structures (forces) according to their fitness to the experimental data, preparing the stage for a more general model-selection and validation strategy inspired by probabilistic data analysis. Finally, we review the essential aspects of our experimental setup and measurement technique.
Institute of Scientific and Technical Information of China (English)
Jinhong Wang; Weixia Chen; Xiuhui Zhang; Pengqiu Min; Rongbo Liu; Hengxuan Yang
2005-01-01
OBJECTIVE To prospectively investigate the correlation between the enhancement parameters of a dynamic-CT (D-CT) scan for renal cell carcinomas (RCC) and the carcinoma tissue microvessel density (MVD) in renal cell carcinomas (RCC).METHODS Twenty-four cases of renal cell carcinoma verifyied by histopathology were scanned via dynamic-CT, followed by a whole kidney scan. Enhancement parameters were derived as follows .The slope of the contrast media uptake curve (S), area under the curve(AR), the density difference before and after tissue enhancement (△HU) and tissue blood ratio (TBR) were calculated for all lesions. Time-density curve types were ranked from the lowest to the highest of the slope of the contrast media uptake curve (S) as type A, B and C. Pathologic slides corresponding to the CT imagings were subjected to CD34 monoclonal antibodies, then were evaluated with an image analyzer to count hot spots of MVD. By using the Spearman rank correlation tests, statistical analysis was performed to determine the strength of the relationship between enhancement parameters and MVD determinations.RESULTS The carcinoma tissue MVD showed a direct correlation with the enhancement parameters of D-CT (r=0.54, r=0.62, r=0.55, r=0.64, r=0.44,P＜ 0.05). Moreover the S, △HU, TBR and type curves all demonstrated a strong correlation with the MVD. By analyzing the various enhancement parameters of the time-density curves, the relationship between the enhancement CT parameters corresponding to the tumor's MVD was identified.CONCLUSION A dynamic spiral-CT scan may be a helpful method as a measurement of tumor angiogenesis in vivo in RCC.
Simulation of pedestrian evacuation based on an improved dynamic parameter model
Institute of Scientific and Technical Information of China (English)
Zhu Nuo; Jia Bin; Shao Chun-Fu; Yue Hao
2012-01-01
An improved dynamic parameter model is presented based on cellular automata.The dynamic parameters,including direction parameter,empty parameter,and cognition parameter,are formulated to simplify tactically the process of making decisions for pedestrians.The improved model reflects the judgement of pedestrians on surrounding conditions and the action of choosing or decision.According to the two-dimensional cellular automaton Moore neighborhood we establish the pedestrian moving rule,and carry out corresponding simulations of pedestrian evacuation.The improved model considers the impact of pedestrian density near exits on the evacuation process.Simulated and experimental results demonstrate that the improvement makes sense due to the fact that except for the spatial distance to exits,people also choose an exit according to the pedestrian density around exits.The impact factors α,β,and γ are introduced to describe transition payoff,and their optimal values are determined through simulation.Moreover,the effects of pedestrian distribution,pedestrian density,and the width of exits on the evacuation time are discussed.The optimal exit layout,i.e.,the optimal position and width,is offered.The comparison between the simulated results obtained with the improved model and that from a previous model and experiments indicates that the improved model can reproduce experimental results well.Thus,it has great significance for further study,and important instructional meaning for pedestrian evacuation so as to reduce the number of casualties.
Sekihara, Takayasu
2016-01-01
For a general two-body bound state in quantum mechanics, both in the stable and decaying cases, we establish a way to extract its two-body wave function in momentum space from the scattering amplitude of the constituent two particles. For this purpose, we first show that the two-body wave function of the bound state corresponds to the residue of the off-shell scattering amplitude at the bound state pole. Then, we examine our scheme to extract the two-body wave function from the scattering amplitude in several schematic models. As a result, the two-body wave functions from the Lippmann--Schwinger equation coincides with that from the Schr\\"{o}dinger equation for an energy-independent interaction. Of special interest is that the two-body wave function from the scattering amplitude is automatically scaled; the norm of the two-body wave function, to which we refer as the compositeness, is unity for an energy-independent interaction, while the compositeness deviates from unity for an energy-dependent interaction, ...
Optimal Design of Measurement Programs for the Parameter Identification of Dynamic Systems
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune
The design of a measured program devoted to parameter identification of structural dynamic systems is considered, the design problem is formulated as an optimization problem due to minimize the total expected cost of the measurement program. All the calculations are based on a priori knowledge an...... in a simply supported plane, vibrating beam model. Results show optimal number of sensors and their locations....... and engineering judgement. One of the contribution of the approach is that the optimal nmber of sensors can be estimated. This is sown in an numerical example where the proposed approach is demonstrated. The example is concerned with design of a measurement program for estimating the modal damping parameters...
Parameter estimation of breast tumour using dynamic neural network from thermal pattern
Directory of Open Access Journals (Sweden)
Elham Saniei
2016-11-01
Full Text Available This article presents a new approach for estimating the depth, size, and metabolic heat generation rate of a tumour. For this purpose, the surface temperature distribution of a breast thermal image and the dynamic neural network was used. The research consisted of two steps: forward and inverse. For the forward section, a finite element model was created. The Pennes bio-heat equation was solved to find surface and depth temperature distributions. Data from the analysis, then, were used to train the dynamic neural network model (DNN. Results from the DNN training/testing confirmed those of the finite element model. For the inverse section, the trained neural network was applied to estimate the depth temperature distribution (tumour position from the surface temperature profile, extracted from the thermal image. Finally, tumour parameters were obtained from the depth temperature distribution. Experimental findings (20 patients were promising in terms of the model’s potential for retrieving tumour parameters.
Dynamic hydrologic modeling using the zero-parameter Budyko model with instantaneous dryness index
Biswal, Basudev
2016-09-01
Long-term partitioning of hydrologic quantities is achieved by using the zero-parameter Budyko model which defines a dryness index. However, this approach is not suitable for dynamic partitioning particularly at diminishing timescales, and therefore, a universally applicable zero-parameter model remains elusive. Here an instantaneous dryness index is proposed which enables dynamic hydrologic modeling using the Budyko model. By introducing a "decay function" that characterizes the effects of antecedent rainfall and solar energy on the dryness state of a basin at a time, I propose the concept of instantaneous dryness index and use the Budyko function to perform continuous hydrologic partitioning. Using the same decay function, I then obtain discharge time series from the effective rainfall time series. The model is evaluated by considering data form 63 U.S. Geological Survey basins. Results indicate the possibility of using the proposed framework as an alternative platform for prediction in ungagued basins.
Order parameters in the Landau–de Gennes theory – the static and dynamic scenarios
Majumdar, Apala
2011-02-17
We obtain quantitative estimates for the scalar order parameters of liquid crystal configurations in three-dimensional geometries, within the Landau-de Gennes framework. We consider both static equilibria and non-equilibrium dynamics and we include external fields and surface anchoring energies in our formulation. Using maximum principle-type arguments, we obtain explicit bounds for the corresponding scalar order parameters in both static and dynamic situations; these bounds are given in terms of the material-dependent thermotropic coefficients, electric field strength and surface anchoring coefficients. These bounds provide estimates for the degree of orientational ordering, quantify the competing effects of the different energetic contributions and can be used to test the accuracy of numerical simulations. © 2011 Taylor & Francis.
The Figure and Dynamical Parameters of Io Inferred from Internal Structure Models
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The recent Galileo spacecraft explored Jupiter and its satellite system and provided us with new geodetic data. In order to discuss the dynamical param-eters and secular tidal effect of Io, the theory of synchronous satellite is described in detail. Using the new geodetic data of Io, two sets of Io's internal structure models are constructed based on the asthenosphere assumption. The liberation parameters α, β, γ and dynamical flattening H are calculated for the models of Io.A comparison of Io with the Moon indicates that they are quite different in many characteristics in spite of the fact that they are approximately equal in mass and size and that they both orbit synchronously.
Buksman Hollander, Efrain; de Luca, Jayme
2003-02-01
We find a two-degree-of-freedom Hamiltonian for the time-symmetric problem of straight line motion of two electrons in direct relativistic interaction. This time-symmetric dynamical system appeared 100 years ago and it was popularized in the 1940s by the work of Wheeler and Feynman in electrodynamics, which was left incomplete due to the lack of a Hamiltonian description. The form of our Hamiltonian is such that the action of a Lorentz transformation is explicitly described by a canonical transformation (with rescaling of the evolution parameter). The method is closed and defines the Hamitonian in implicit form without power expansions. We outline the method with an emphasis on the physics of this complex conservative dynamical system. The Hamiltonian orbits are calculated numerically at low energies using a self-consistent steepest-descent method (a stable numerical method that chooses only the nonrunaway solution). The two-degree-of-freedom Hamiltonian suggests a simple prescription for the canonical quantization of the relativistic two-body problem.
The use of an electrical-fluid dynamic parameter in cooling tower
Energy Technology Data Exchange (ETDEWEB)
Sirena, J.A. [Univ. Nacional de Cordoba (Argentina). Facultad de Ciencias Exactas
1999-11-01
An Electrical-Fluid Dynamic quality parameter is defined for a mechanical draft type cooling tower. It allows to evaluate the efficiency of the transformation of the electrical power input into kinetic energy of the air flow. It could also be used to calculate the active electrical power of the tower at different working conditions. Results obtained through tests in a small counterflow water cooling tower are shown.
Hamilton's Equations with Euler Parameters for Rigid Body Dynamics Modeling. Chapter 3
Shivarama, Ravishankar; Fahrenthold, Eric P.
2004-01-01
A combination of Euler parameter kinematics and Hamiltonian mechanics provides a rigid body dynamics model well suited for use in strongly nonlinear problems involving arbitrarily large rotations. The model is unconstrained, free of singularities, includes a general potential energy function and a minimum set of momentum variables, and takes an explicit state space form convenient for numerical implementation. The general formulation may be specialized to address particular applications, as illustrated in several three dimensional example problems.
Soares,Priscilla Barbosa Ferreira; Nunes,Sarah Arantes; Franco,Sinésio Domingues; Pires, Raphael Rezende; Zanetta-Barbosa,Darceny; Soares, Carlos José
2014-01-01
The clinical performance of dental implants is strongly defined by biomechanical principles. The aim of this study was to quantify the Vicker's hardness (VHN) and elastic modulus (E) surround bone to dental implant in different regions, and to discuss the parameters of dynamic microindantion test. Ten cylindrical implants with morse taper interface (Titamax CM, Neodent; 3.5 mm diameter and 7 mm a height) were inserted in rabbit tibia. The mechanical properties were analyzed using microhardnes...
The relationship between gait parameters and static and dynamic balance in the elderly
Razieh Tabe; VahidReza Borhaninejad; Yahya Sokhanguei; Heydar Sadeghi; Razieh Sadat Hossieni
2015-01-01
Background: The physiological changes and muscle problems can lead to balance disorder and increased risk of falling among the elderly. Therefore, it is necessary to evaluate the factors associated with balance in the elderly, to increase their awareness of the falling risks and to provide them with appropriate assistive devices.. Hence, this study was carried out to investigate the relationship between some gait parameters and static and dynamic balance in the elderly. Methods: In this qu...
The relationship between gait parameters and static and dynamic balance in the elderly
Directory of Open Access Journals (Sweden)
Razieh Tabe
2015-02-01
Full Text Available Background: The physiological changes and muscle problems can lead to balance disorder and increased risk of falling among the elderly. Therefore, it is necessary to evaluate the factors associated with balance in the elderly, to increase their awareness of the falling risks and to provide them with appropriate assistive devices.. Hence, this study was carried out to investigate the relationship between some gait parameters and static and dynamic balance in the elderly. Methods: In this quasi-experimental study, 44 men and women in two groups (22 per group participated as the study sample. The measured values included step length, stride length, step width, rotating angle of toes, and static and dynamic balance. The static balance was measured with Romberg test and dynamic balance with TUGTU test. Data were analysed by SPSS-15 software using t-test and Pearson correlation coefficient. Results: There was a significant relationship between step length and stride length with static and dynamic balance and between step width and dynamic balance (p0/05. But no significant relationship was reported between step width and static balance and between rotating angle of toes with static and dynamic balance among the elderly. Conclusions: the elderly balance can be improved by decreasing the step length and increasing the stride length, thereby reducing the possibility of their falling.
Tandem strip mill's multi-parameter coupling dynamic modeling based on the thickness control
Peng, Yan; Zhang, Yang; Sun, Jianliang; Zang, Yong
2015-03-01
The rolling process is determined by the interaction of a number of different movements, during which the relative movement occurs between the vibrating roll system and the rolled piece, and the roll system's vibration interacts with the strip's deformation and rigid movement. So many parameters being involved leads to a complex mechanism of this coupling effect. Through testing and analyzing the vibration signals of the mill in the rolling process, the rolling mill's coupled model is established with comprehensive consideration of the coupling interaction between the mill's vertical vibration, its torsional vibration and the working roll's horizontal vibration, and vibration characteristics of different forms of rolling mill's vibration are analyzed under the coupling effect. With comprehensive attention to the relationship between the roll system, the moving strip and the rolling parameters' dynamic properties, and also from the strip thickness control point of view, further research is done on the coupling mechanism between the roll system's movement and the moving strip's characteristics in the rolling process. As a result, the law of inertial coupling and the stiffness coupling effect caused by different forms of the roll system's vibration is determined and the existence of nonlinear characteristics caused by the elastic deformation of moving strip is also found. Furthermore, a multi-parameter coupling-dynamic model is established which takes the tandem strip mill as its research object by making a detailed kinematics analysis of the roll system and using the principle of virtual work. The coupling-dynamic model proposes the instruction to describe the roll system's movement, and analyzes its dynamic response and working stability, and provides a theoretical basis for the realization of the strip thickness' dynamic control.
Longitudinal control of aircraft dynamics based on optimization of PID parameters
Deepa, S. N.; Sudha, G.
2016-03-01
Recent years many flight control systems and industries are employing PID controllers to improve the dynamic behavior of the characteristics. In this paper, PID controller is developed to improve the stability and performance of general aviation aircraft system. Designing the optimum PID controller parameters for a pitch control aircraft is important in expanding the flight safety envelope. Mathematical model is developed to describe the longitudinal pitch control of an aircraft. The PID controller is designed based on the dynamic modeling of an aircraft system. Different tuning methods namely Zeigler-Nichols method (ZN), Modified Zeigler-Nichols method, Tyreus-Luyben tuning, Astrom-Hagglund tuning methods are employed. The time domain specifications of different tuning methods are compared to obtain the optimum parameters value. The results prove that PID controller tuned by Zeigler-Nichols for aircraft pitch control dynamics is better in stability and performance in all conditions. Future research work of obtaining optimum PID controller parameters using artificial intelligence techniques should be carried out.
Yang, Li; Sun, Rui; Hase, William L
2011-11-08
In a previous study (J. Chem. Phys.2008, 129, 094701) it was shown that for a large molecule, with a total energy much greater than its barrier for decomposition and whose vibrational modes are harmonic oscillators, the expressions for the classical Rice-Ramsperger-Kassel-Marcus (RRKM) (i.e., RRK) and classical transition-state theory (TST) rate constants become equivalent. Using this relationship, a molecule's unimolecular rate constants versus temperature may be determined from chemical dynamics simulations of microcanonical ensembles for the molecule at different total energies. The simulation identifies the molecule's unimolecular pathways and their Arrhenius parameters. In the work presented here, this approach is used to study the thermal decomposition of CH3-NH-CH═CH-CH3, an important constituent in the polymer of cross-linked epoxy resins. Direct dynamics simulations, at the MP2/6-31+G* level of theory, were used to investigate the decomposition of microcanonical ensembles for this molecule. The Arrhenius A and Ea parameters determined from the direct dynamics simulation are in very good agreement with the TST Arrhenius parameters for the MP2/6-31+G* potential energy surface. The simulation method applied here may be particularly useful for large molecules with a multitude of decomposition pathways and whose transition states may be difficult to determine and have structures that are not readily obvious.
Kostka, Filip; Gallovic, Frantisek
2017-04-01
We perform dynamic finite-extent source inversion to study the source processes of three earthquakes that occurred close to Amatrice and Norcia, Central Italy, in August-October 2016. The events had moment magnitudes of 6.1-6.5 and resulted in >300 fatalities. To that end, we utilize a modified version of dynamic inversion code by Twardzik et al. (2014). The direct problem is solved by 3D fourth-order staggered-grid finite difference method in a box assuming linear slip-weakening friction law on a planar fault (Madariaga et al., 1998). The optimal solution is sought using the Neighborhood Algorithm by Sambridge (1999). We invert displacement waveforms from the 20-30 nearest stations. The distribution and evolution of slip calculated from physical parameters (stress drop, frictional properties) obtained from the dynamic inversion are compared with results of kinematic inversions and discussed in terms of fault mechanics.
Kaspi, Yohai
2014-01-01
The recent discoveries of terrestrial exoplanets and super Earths extending over a broad range of orbital and physical parameters suggests that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone---including transitions to Snowball-like states and runaway-greenhouse feedbacks---depend on the equator-to-pole temperature differences, pattern of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model (GCM) including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, planetary mass,...
Reinbolt, Jeffrey A; Haftka, Raphael T; Chmielewski, Terese L; Fregly, Benjamin J
2007-05-01
Variations in joint parameter (JP) values (axis positions and orientations in body segments) and inertial parameter (IP) values (segment masses, mass centers, and moments of inertia) as well as kinematic noise alter the results of inverse dynamics analyses of gait. Three-dimensional linkage models with joint constraints have been proposed as one way to minimize the effects of noisy kinematic data. Such models can also be used to perform gait optimizations to predict post-treatment function given pre-treatment gait data. This study evaluates whether accurate patient-specific JP and IP values are needed in three-dimensional linkage models to produce accurate inverse dynamics results for gait. The study was performed in two stages. First, we used optimization analyses to evaluate whether patient-specific JP and IP values can be calibrated accurately from noisy kinematic data, and second, we used Monte Carlo analyses to evaluate how errors in JP and IP values affect inverse dynamics calculations. Both stages were performed using a dynamic, 27 degrees-of-freedom, full-body linkage model and synthetic (i.e., computer generated) gait data corresponding to a nominal experimental gait motion. In general, JP but not IP values could be found accurately from noisy kinematic data. Root-mean-square (RMS) errors were 3 degrees and 4 mm for JP values and 1 kg, 22 mm, and 74 500 kg * mm2 for IP values. Furthermore, errors in JP but not IP values had a significant effect on calculated lower-extremity inverse dynamics joint torques. The worst RMS torque error averaged 4% bodyweight * height (BW * H) due to JP variations but less than 0.25% (BW * H) due to IP variations. These results suggest that inverse dynamics analyses of gait utilizing linkage models with joint constraints should calibrate the model's JP values to obtain accurate joint torques.
Paramfit: automated optimization of force field parameters for molecular dynamics simulations.
Betz, Robin M; Walker, Ross C
2015-01-15
The generation of bond, angle, and torsion parameters for classical molecular dynamics force fields typically requires fitting parameters such that classical properties such as energies and gradients match precalculated quantum data for structures that scan the value of interest. We present a program, Paramfit, distributed as part of the AmberTools software package that automates and extends this fitting process, allowing for simplified parameter generation for applications ranging from single molecules to entire force fields. Paramfit implements a novel combination of a genetic and simplex algorithm to find the optimal set of parameters that replicate either quantum energy or force data. The program allows for the derivation of multiple parameters simultaneously using significantly fewer quantum calculations than previous methods, and can also fit parameters across multiple molecules with applications to force field development. Paramfit has been applied successfully to systems with a sparse number of structures, and has already proven crucial in the development of the Assisted Model Building with Energy Refinement Lipid14 force field.
DYNAMIC PARAMETERS ESTIMATION OF INTERFEROMETRIC SIGNALS BASED ON SEQUENTIAL MONTE CARLO METHOD
Directory of Open Access Journals (Sweden)
M. A. Volynsky
2014-05-01
Full Text Available The paper deals with sequential Monte Carlo method applied to problem of interferometric signals parameters estimation. The method is based on the statistical approximation of the posterior probability density distribution of parameters. Detailed description of the algorithm is given. The possibility of using the residual minimum between prediction and observation as a criterion for the selection of multitude elements generated at each algorithm step is shown. Analysis of input parameters influence on performance of the algorithm has been conducted. It was found that the standard deviation of the amplitude estimation error for typical signals is about 10% of the maximum amplitude value. The phase estimation error was shown to have a normal distribution. Analysis of the algorithm characteristics depending on input parameters is done. In particular, the influence analysis for a number of selected vectors of parameters on evaluation results is carried out. On the basis of simulation results for the considered class of signals, it is recommended to select 30% of the generated vectors number. The increase of the generated vectors number over 150 does not give significant improvement of the obtained estimates quality. The sequential Monte Carlo method is recommended for usage in dynamic processing of interferometric signals for the cases when high immunity is required to non-linear changes of signal parameters and influence of random noise.
On the rotational equations of motion in rigid body dynamics when using Euler parameters.
Sherif, Karim; Nachbagauer, Karin; Steiner, Wolfgang
Many models of three-dimensional rigid body dynamics employ Euler parameters as rotational coordinates. Since the four Euler parameters are not independent, one has to consider the quaternion constraint in the equations of motion. This is usually done by the Lagrange multiplier technique. In the present paper, various forms of the rotational equations of motion will be derived, and it will be shown that they can be transformed into each other. Special attention is hereby given to the value of the Lagrange multiplier and the complexity of terms representing the inertia forces. Particular attention is also paid to the rotational generalized external force vector, which is not unique when using Euler parameters as rotational coordinates.
Matrix Elements of One- and Two-Body Operators in the Unitary Group Approach (II) - Application
Institute of Scientific and Technical Information of China (English)
DAI Lian-Rong; PAN Feng
2001-01-01
Simple analytical expressions for one- and two-body matrix elements in the unitary group approach to the configuration interaction problems of many-electron systems are obtained based on the previous results for general Un irreps.
A simplified dynamic method for field capacity estimation and its parameter analysis
Institute of Scientific and Technical Information of China (English)
Zhen-tao CONG; Hua-fang LÜ; Guang-heng NI
2014-01-01
This paper presents a simplified dynamic method based on the definition of field capacity. Two soil hydraulic characteristics models, the Brooks-Corey (BC) model and the van Genuchten (vG) model, and four soil data groups were used in this study. The relative drainage rate, which is a unique parameter and independent of the soil type in the simplified dynamic method, was analyzed using the pressure-based method with a matric potential of−1/3 bar and the flux-based method with a drainage flux of 0.005 cm/d. As a result, the relative drainage rate of the simplified dynamic method was determined to be 3% per day. This was verified by the similar field capacity results estimated with the three methods for most soils suitable for cultivating plants. In addition, the drainage time calculated with the simplified dynamic method was two to three days, which agrees with the classical definition of field capacity. We recommend the simplified dynamic method with a relative drainage rate of 3% per day due to its simple application and clearly physically-based concept.
Directory of Open Access Journals (Sweden)
Lili Guo
2015-06-01
Full Text Available Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates, starting rolling temperatures, and rolling speeds, and the effects of rolling parameters (i.e., temperature, equivalent strain, and rolling time on dynamically recrystallized (DRX microstructures of AZ31 alloy during hot rolling were studied quantitatively. The temperature-strain dependence of the high-angle grain boundary fraction (HAGB% was examined through electron backscattered diffraction. Results showed that as-rolled microstructures with high HAGB% may be obtained under average rolling temperatures of 270–320 °C, equivalent strains higher than 0.8, and a rolling speed of 246 mm/s. These results may be related to the DRX kinetics and dynamic recovery which are controlled by deformation temperature and strain. HAGB% decreased with increasing rolling time (decreasing rolling speed, which is attributed to dynamic recovery, and the recrystallized grain size decreased as rolling time increased. However, further increases in rolling time increased average grain sizes but decreased mean subgrain sizes; these results are attributed to increases in the low-angle grain boundary (LAGB length per unit area with rolling time. LAGB formation was controlled by dynamic recovery, which consistently follows polygonization or formation of new subgrains inside larger grains; hence, average subgrain sizes decreased with the rolling time. The effect of dynamic recovery on HAGB and LAGB formation and their related mechanisms over a wide range of strains and temperatures were discussed in detail.
Nonperturbative quantum dynamics of the order parameter in the BCS pairing model
Galitski, Victor
2010-08-01
We consider quantum dynamics of the order parameter in the discrete pairing model (Richardson model) in thermodynamic equilibrium. The integrable Richardson Hamiltonian is represented as a direct sum of Hamiltonians acting in different Hilbert spaces of single-particle and paired/empty states. This allows us to factorize the full thermodynamic partition function into a combination of simple terms associated with real spins on singly occupied states and the partition function of the quantum XY model for Anderson pseudospins associated with the paired/empty states. Using coherent-state path integral, we calculate the effects of superconducting phase fluctuations exactly. The contribution of superconducting amplitude fluctuations to the partition function in the broken-symmetry phase is shown to follow from the Bogoliubov-de Gennes equations in imaginary time. These equations in turn allow several interesting mappings, e.g., they are shown to be in a one-to-one correspondence with the one-dimensional Schrödinger equation in supersymmetric quantum mechanics. However, the most practically useful approach to calculate functional determinants is found to be via an analytical continuation of the quantum order parameter to real time, Δ(τ→it) , such that the problem maps onto that of a driven two-level system. The contribution of a particular dynamic order parameter, Δ(τ) , to the partition function is shown to correspond to the sum of the Berry phase and dynamic phase accumulated by the pseudospin. We also examine a family of exact solutions for two-level-system dynamics on a class of elliptic functions and suggest a compact expression to estimate the functional determinants on such trajectories. The possibility of having quantum soliton solutions coexisting with classical BCS mean field is discussed.
Tandem Strip Mill’s Multi-parameter Coupling Dynamic Modeling Based on the Thickness Control
Institute of Scientific and Technical Information of China (English)
PENG Yan; ZHANG Yang; SUN Jianliang; ZANG Yong
2015-01-01
The rolling process is determined by the interaction of a number of different movements, during which the relative movement occurs between the vibrating roll system and the rolled piece, and the roll system’s vibration interacts with the strip’s deformation and rigid movement. So many parameters being involved leads to a complex mechanism of this coupling effect. Through testing and analyzing the vibration signals of the mill in the rolling process, the rolling mill’s coupled model is established with comprehensive consideration of the coupling interaction between the mill’s vertical vibration, its torsional vibration and the working roll’s horizontal vibration, and vibration characteristics of different forms of rolling mill’s vibration are analyzed under the coupling effect. With comprehensive attention to the relationship between the roll system, the moving strip and the rolling parameters’ dynamic properties, and also from the strip thickness control point of view, further research is done on the coupling mechanism between the roll system’s movement and the moving strip’s characteristics in the rolling process. As a result, the law of inertial coupling and the stiffness coupling effect caused by different forms of the roll system’s vibration is determined and the existence of nonlinear characteristics caused by the elastic deformation of moving strip is also found. Furthermore, a multi-parameter coupling-dynamic model is established which takes the tandem strip mill as its research object by making a detailed kinematics analysis of the roll system and using the principle of virtual work. The coupling-dynamic model proposes the instruction to describe the roll system’s movement, and analyzes its dynamic response and working stability, and provides a theoretical basis for the realization of the strip thickness’ dynamic control.
Matzelle, A.; Montalto, V.; Sarà, G.; Zippay, M.; Helmuth, B.
2014-11-01
Dynamic Energy Budget (DEB) models serve as a powerful tool for describing the flow of energy through organisms from assimilation of food to utilization for maintenance, growth and reproduction. The DEB theory has been successfully applied to several bivalve species to compare bioenergetic and physiological strategies for the utilization of energy. In particular, mussels within the Mytilus edulis complex (M. edulis, M. galloprovincialis, and M. trossulus) have been the focus of many studies due to their economic and ecological importance, and their worldwide distribution. However, DEB parameter values have never been estimated for Mytilus californianus, a species that is an ecological dominant on rocky intertidal shores on the west coast of North America and which likely varies considerably from mussels in the M. edulis complex in its physiology. We estimated a set of DEB parameters for M. californianus using the covariation method estimation procedure and compared these to parameter values from other bivalve species. Model parameters were used to compare sensitivity to environmental variability among species, as a first examination of how strategies for physiologically contending with environmental change by M. californianus may differ from those of other bivalves. Results suggest that based on the parameter set obtained, M. californianus has favorable energetic strategies enabling it to contend with a range of environmental conditions. For instance, the allocation fraction of reserve to soma (κ) is among the highest of any bivalves, which is consistent with the observation that this species can survive over a wide range of environmental conditions, including prolonged periods of starvation.
Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li
2015-05-01
In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.
Li, Junlan; Huang, Hongzhou; Yan, Shaoze; Yang, Yunqiang
2017-07-01
Joint clearance and the uncertainty of geometric and physical parameters significantly influence the kinematic accuracy and dynamic response of space deployable mechanisms. Such mechanisms have been widely employed in astronautic missions to improve the capabilities of launchers. This paper proposes a methodology to investigate the kinematic accuracy and dynamic performance of space deployable mechanism with joint clearance while considering parameter uncertainty. The model of space deployable mechanism with a planar revolute joint is provided. With consideration of several uncertain parameters, the solving procedure of the dynamic equations is presented based on the Monte Carlo method. A case study is conducted to reveal the effect of parameter uncertainty on its kinematic accuracy and dynamic performance. The results indicate that parameter uncertainty should be considered to accurately evaluate the performance of long-term operating space deployable mechanisms, especially for such systems with clearance joints. According to the results, brief suggestions for design and evaluation of the mechanisms are provided.
Analysis of two-body nonleptonic B decays involving light mesons in the standard model
Ali, A.; Greub, C.
1998-03-01
We report a theoretical analysis of the exclusive nonleptonic decays of the B+/- and B0 mesons into two light mesons, some of which have been measured recently by the CLEO Collaboration. Our analysis is carried out in the context of an effective Hamiltonian based on the standard model (SM), using next-to-leading order perturbative QCD calculations. We explicitly take into account the O(αs) penguin-loop diagrams of all four-Fermi operators and the O(αs) tree-level diagram of the chromomagnetic dipole operator, and give a prescription for including their effects in nonleptonic two-body decays. Using a factorization ansatz for the hadronic matrix elements, we show that existing data, in particular, the branching ratios B(B+/--->η'K+/-), B(B+/--->π+/-K0), B(B0(B0¯)-->π-/+K+/-), and B(B+/--->ωh+/-)(h+/-=π+/-,K+/-), can be accounted for in this approach. Thus, theoretical scenarios with a substantially enhanced Wilson coefficient of the chromomagnetic dipole operator (as compared to the SM) and/or those with a substantial color-singlet cc¯ component in the wave function of η' are not required by these data. We predict, among other decay rates, the branching ratios for the decays B0(B0¯)-->π+/-π-/+ and B+/--->π0π+/-, which are close to the present experimental limits. Implications of some of these measurements for the parameters of the CKM matrix are presented.
Dynamic parameters test of Haiyang Nuclear Power Engineering in reactor areas, China
Zhou, N.; Zhao, S.; Sun, L.
2012-12-01
Haiyang Nuclear Power Project is located in Haiyang city, China. It consists of 6×1000MW AP1000 Nuclear Power generator sets. The dynamic parameters of the rockmass are essential for the design of the nuclear power plant. No.1 and No.2 reactor area are taken as research target in this paper. Sonic logging, single hole and cross-hole wave velocity are carried out respectively on the site. There are four types of rock lithology within the measured depth. They are siltstone, fine sandstone, shale and allgovite. The total depth of sonic logging is 409.8m and 2049 test points. The sound wave velocity of the rocks are respectively 5521 m/s, 5576m/s, 5318 m/s and 5576 m/s. Accroding to the statistic data, among medium weathered fine sandstone, fairly broken is majority, broken and relatively integrity are second, part of integrity. Medium weathered siltstone, relatively integrity is mojority, fairly broken is second. Medium weathered shale, fairly broken is majority, broken and relatively integrity for the next and part of integrity. Slight weathered fine sandstone, siltstone, shale and allgovite, integrity is the mojority, relatively integrity for the next, part of fairly broken.The single hole wave velocity tests are set in two boreholesin No.1 reactor area and No.2 reactor area respectively. The test depths of two holes are 2-24m, and the others are 2-40m. The wave velocity data are calculated at different depth in each holes and dynamic parameters. According to the test statistic data, the wave velocity and the dynamic parameter values of rockmass are distinctly influenced by the weathering degree. The test results are list in table 1. 3 groups of cross hole wave velocity tests are set for No.1 and 2 reactor area, No.1 reactor area: B16, B16-1, B20(Direction:175°, depth: 100m); B10, B10-1, B11(269°, 40m); B21, B21-1, B17(154°, 40m); with HB16, HB10, HB21 as trigger holes; No.2 reactor area: B47, B47-1, HB51(176°, 100m); B40, B40-1, B41(272°, 40m); B42, B42-1, B
Directory of Open Access Journals (Sweden)
Lei Wang
2014-01-01
Full Text Available A dynamic model of gear transmission system of wind turbine is built with consideration of randomness of loads and parameters. The dynamic response of the system is obtained using the theory of random sampling and the Runge-Kutta method. According to rain flow counting principle, the dynamic meshing forces are converted into a series of luffing fatigue load spectra. The amplitude and frequency of the equivalent stress are obtained using equivalent method of Geber quadratic curve. Moreover, the dynamic reliability model of components and system is built according to the theory of probability of cumulative fatigue damage. The system reliability with the random variation of parameters is calculated and the influence of random parameters on dynamic reliability of components is analyzed. In the end, the results of the proposed method are compared with that of Monte Carlo method. This paper can be instrumental in the design of wind turbine gear transmission system with more advantageous dynamic reliability.
COORDINATION OF THE MOTION PARAMETERS WITHIN STEP-BY-STEP INTEGRATION FOR DYNAMIC EQUATION
Institute of Scientific and Technical Information of China (English)
HuangQingfeng; WangQuanfeng; HuYunchang
2004-01-01
A method is presented that coordinates the calculation of the displacement, velocity and acceleration of structures within the time-steps of different types of step-by-step integration.The dynamic equation is solved using an energy equation and the calculating data of the original method. The method presented is better than the original method in terms of calculating postulations and is in better conformity with the system's movement. Take the Wilson-θ method as an example. By using the coordination process, the calculation precision has been greatly improved (reducing the errors by approximately 90% ), and the greater part of overshooting of the calculation result has been eliminated. The study suggests that the mal-coordination of the motion parameters within the time-step is the major factor that contributes to the result errors of step-by-step integration for the dynamic equation.
Tretyakov, Nikita; Müller, Marcus; Todorova, Desislava; Thiele, Uwe
2013-02-14
We study equilibrium properties of polymer films and droplets on a solid substrate employing particle-based simulation techniques (molecular dynamics) and a continuum description. Parameter-passing techniques are explored that facilitate a detailed comparison of the two models. In particular, the liquid-vapor, solid-liquid, and solid-vapor interface tensions, and the Derjaguin or disjoining pressure are determined by molecular dynamics simulations. This information is then introduced into continuum descriptions accounting for (i) the full curvature and (ii) a long-wave approximation of the curvature (thin film model). A comparison of the dependence of the contact angle on droplet size indicates that the theories agree well if the contact angles are defined in a compatible manner.
Institute of Scientific and Technical Information of China (English)
XU You-Sheng; LIU Yang; HUANG Guo-Xiang
2004-01-01
@@ Digital images (DI) and lattice Boltzmann method (LBM) are used to characterize the threshold dynamic parameters of porous media. Two-dimensional representations of the porous structure are reconstructed from segmentation of digital images obtained from a series of tiny samples. The threshold pressure gradients and threshold Péclet numbers are researched on seven test samples by using LBM. Numerical results are in agreement with that obtained by integrating Darcy's law. The results also indicate that fluids can flow through porous media only if the fluid force is large enough to overcome threshold pressure gradient in porous media. One synthetic case is used to further illustrate the applicability of the proposed technique. In addition, the dynamical rules in our model are local, therefore it can be run on parallel computers with well computational efficiency.
Zhao, He; Sokhansanj, Bahrad A
2007-10-01
Microtubule dynamics play a critical role in cell function and stress response, modulating mitosis, morphology, signaling, and transport. Drugs such as paclitaxel (Taxol) can impact tubulin polymerization and affect microtubule dynamics. While theoretical methods have been previously proposed to simulate microtubule dynamics, we develop a methodology here that can be used to compare model predictions with experimental data. Our model is a hybrid of (1) a simple two-state stochastic formulation of tubulin polymerization kinetics and (2) an equilibrium approximation for the chemical kinetics of Taxol drug binding to microtubule ends. Model parameters are biologically realistic, with values taken directly from experimental measurements. Model validation is conducted against published experimental data comparing optical measurements of microtubule dynamics in cultured cells under normal and Taxol-treated conditions. To compare model predictions with experimental data requires applying a "windowing" strategy on the spatiotemporal resolution of the simulation. From a biological perspective, this is consistent with interpreting the microtubule "pause" phenomenon as at least partially an artifact of spatiotemporal resolution limits on experimental measurement.
Karam, Ayman M.
2016-10-03
Membrane distillation (MD) is an emerging technology that has a great potential for sustainable water desalination. In order to pave the way for successful commercialization of MD-based water desalination techniques, adequate and accurate dynamical models of the process are essential. This paper presents the predictive capabilities of a lumped-parameter dynamic model for direct contact membrane distillation (DCMD) and discusses the results under wide range of steady-state and dynamic conditions. Unlike previous studies, the proposed model captures the time response of the spacial temperature distribution along the flow direction. It also directly solves for the local temperatures at the membrane interfaces, which allows to accurately model and calculate local flux values along with other intrinsic variables of great influence on the process, like the temperature polarization coefficient (TPC). The proposed model is based on energy and mass conservation principles and analogy between thermal and electrical systems. Experimental data was collected to validated the steady-state and dynamic responses of the model. The obtained results shows great agreement with the experimental data. The paper discusses the results of several simulations under various conditions to optimize the DCMD process efficiency and analyze its response. This demonstrates some potential applications of the proposed model to carry out scale up and design studies. © 2016
Huisman, Jef; Sommeijer, Ben
2002-10-01
Phytoplankton use light for photosynthesis, and the light flux decreases with depth. As a result of this simple light dependence, reaction-advection-diffusion models describing the dynamics of phytoplankton species contain an integral over depth. That is, models that simulate phytoplankton dynamics in relation to mixing processes generally have the form of an integro-partial differential equation (integro-PDE). Integro-PDEs are computationally more demanding than standard PDEs. Here, we outline a reliable and efficient technique for numerical simulation of integro-PDEs. The simulation technique is illustrated by several examples on the population dynamics of sinking phytoplankton, using both single-species models and competition models with several phytoplankton species. Our results confirm recent findings that Sverdrup's critical-depth theory breaks down if turbulent mixing is reduced below a critical turbulence. In fact, our results show that suitable conditions for bloom development of sinking phytoplankton depend on a number of critical parameters, including a minimal depth of the thermocline, a maximal depth of the thermocline, a minimal turbulence, and a maximal turbulence. We therefore conclude that models that do not carefully consider the population dynamics of phytoplankton in relation to the turbulence structure of the water column may easily lead to erroneous predictions.
Pseudo-dynamic source modelling with 1-point and 2-point statistics of earthquake source parameters
Song, S. G.
2013-12-24
Ground motion prediction is an essential element in seismic hazard and risk analysis. Empirical ground motion prediction approaches have been widely used in the community, but efficient simulation-based ground motion prediction methods are needed to complement empirical approaches, especially in the regions with limited data constraints. Recently, dynamic rupture modelling has been successfully adopted in physics-based source and ground motion modelling, but it is still computationally demanding and many input parameters are not well constrained by observational data. Pseudo-dynamic source modelling keeps the form of kinematic modelling with its computational efficiency, but also tries to emulate the physics of source process. In this paper, we develop a statistical framework that governs the finite-fault rupture process with 1-point and 2-point statistics of source parameters in order to quantify the variability of finite source models for future scenario events. We test this method by extracting 1-point and 2-point statistics from dynamically derived source models and simulating a number of rupture scenarios, given target 1-point and 2-point statistics. We propose a new rupture model generator for stochastic source modelling with the covariance matrix constructed from target 2-point statistics, that is, auto- and cross-correlations. Our sensitivity analysis of near-source ground motions to 1-point and 2-point statistics of source parameters provides insights into relations between statistical rupture properties and ground motions. We observe that larger standard deviation and stronger correlation produce stronger peak ground motions in general. The proposed new source modelling approach will contribute to understanding the effect of earthquake source on near-source ground motion characteristics in a more quantitative and systematic way.
Valero, Francisco; Iriarte, Xabier; Mata, Vicente; Ros, Javier
2013-08-01
The identification of dynamic parameters in low-mobility mechanical systems is addressed and applied to short long arm (SLA) front car suspension. The main goal of the identification technique is to obtain, from experimental measurements, the values of those dynamic parameters (masses, location of the centre of masses, terms of the inertial matrix of the links, constant friction terms and elastic and viscous damping constant terms) that affect the dynamic behaviour of the system. Moreover, additional but important information that could be obtained from the procedure is related to the weight of those terms inside the dynamics of the system, so that simplified dynamic models based on relevant and well-identified parameters can be established. First, a systematic procedure will be presented for obtaining the equations of motion in a linear form with regard to the dynamic parameters to be identified. The main drawbacks related to the identification of parameters in low-mobility mechanisms will be pointed out, mainly the difficulty of determining a natural cutoff point into the singular values of the observation matrix which allows us to determine the true dimension of the set of base parameters and of obtaining an observation matrix well conditioned from the numerical point of view that allows an identification in the presence of measurement error. The procedure proposed for overcoming these problems will be based on the development of symbolic relationships among the physical parameters in order to determine the true rank of the observation matrix and on the consideration of a reduced subset of the base parameters set. These relevant parameters will be selected according to their influence on the dynamic behaviour of the mechanical system. A virtual benchmark will be used for testing purposes. The dynamic models based on relevant parameters show a better adjustment than the complete ones, mainly when the level of noise in the measurements used in the identification
Closed-loop Dynamic Parameter Identification of Robot Manipulators Using Modified Fourier Series
Directory of Open Access Journals (Sweden)
Wenxiang Wu
2012-05-01
Full Text Available This paper concerns the problem of dynamic parameter identification of robot manipulators and proposes a closed‐loop identification procedure using modified Fourier series (MFS as exciting trajectories. First, a static continuous friction model is involved to model joint friction for realizable friction compensation in controller design. Second, MFS satisfying the boundary conditions are firstly designed as periodic exciting trajectories. To minimize the sensitivity to measurement noise, the coefficients of MFS are optimized according to the condition number criterion. Moreover, to obtain accurate parameter estimates, the maximum likelihood estimation (MLE method considering the influence of measurement noise is adopted. The proposed identification procedure has been implemented on the first three axes of the QIANJIANG‐I 6‐DOF robot manipulator. Experiment results verify the effectiveness of the proposed approach, and comparison between identification using MFS and that using finite Fourier series (FFS reveals that the proposed method achieves better identification accuracy.
Closed-Loop Dynamic Parameter Identification of Robot Manipulators Using Modified Fourier Series
Directory of Open Access Journals (Sweden)
Wenxiang Wu
2012-05-01
Full Text Available This paper concerns the problem of dynamic parameter identification of robot manipulators and proposes a closed-loop identification procedure using modified Fourier series (MFS as exciting trajectories. First, a static continuous friction model is involved to model joint friction for realizable friction compensation in controller design. Second, MFS satisfying the boundary conditions are firstly designed as periodic exciting trajectories. To minimize the sensitivity to measurement noise, the coefficients of MFS are optimized according to the condition number criterion. Moreover, to obtain accurate parameter estimates, the maximum likelihood estimation (MLE method considering the influence of measurement noise is adopted. The proposed identification procedure has been implemented on the first three axes of the QIANJIANG-I 6-DOF robot manipulator. Experiment results verify the effectiveness of the proposed approach, and comparison between identification using MFS and that using finite Fourier series (FFS reveals that the proposed method achieves better identification accuracy.
Bernard, O; Hadj-Sadok, Z; Dochain, D; Genovesi, A; Steyer, J P
2001-11-20
This paper deals with the development and the parameter identification of an anaerobic digestion process model. A two-step (acidogenesis-methanization) mass-balance model has been considered. The model incorporates electrochemical equilibria in order to include the alkalinity, which has to play a central role in the related monitoring and control strategy of a treatment plant. The identification is based on a set of dynamical experiments designed to cover a wide spectrum of operating conditions that are likely to take place in the practical operation of the plant. A step by step identification procedure to estimate the model parameters is presented. The results of 70 days of experiments in a 1-m(3) fermenter are then used to validate the model.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Gyro's fault diagnosis plays a critical role in inertia navigation systems for higher reliability and precision. A new fault diagnosis strategy based on the statistical parameter analysis (SPA) and support vector machine(SVM) classification model was proposed for dynamically tuned gyroscopes (DTG). The SPA, a kind of time domain analysis approach, was introduced to compute a set of statistical parameters of vibration signal as the state features of DTG, with which the SVM model, a novel learning machine based on statistical learning theory (SLT), was applied and constructed to train and identify the working state of DTG. The experimental results verify that the proposed diagnostic strategy can simply and effectively extract the state features of DTG, and it outperforms the radial-basis function (RBF) neural network based diagnostic method and can more reliably and accurately diagnose the working state of DTG.
Study on the Stability of Supply Chain System Under Perturbations of Dynamic Parameters
Institute of Scientific and Technical Information of China (English)
YingjinLu; XiaowoTang; ZongfangZhou
2004-01-01
The stability of supply chain system is key to implement efficiently inventory policies and improve quality of service in the supply chain. If the supply chain system were unstable, the lead-time would be uncertain. As a result, directly affects the process of manufacture, and the service level. In this paper, we analyze the stability of the supply chain system under perturbations of dynamic parameters based on the Cobb-Douglas production function and study influences on supply chain performance. We prove that the supply chain system, with the increases of the re-production input funding, becomes unstable. Further, when the optimal combination of input parameter elements, the supply chain system becomes unstable.
Directory of Open Access Journals (Sweden)
W. P. Martignoni
2007-03-01
Full Text Available Cyclone models have been used without relevant modifications for more than a century. Most of the attention has been focused on finding new methods to improve performance parameters. Recently, some studies were conducted to improve equipment performance by evaluating geometric effects on projects. In this work, the effect of cyclone geometry was studied through the creation of a symmetrical inlet and a volute scroll outlet section in an experimental cyclone and comparison to an ordinary single tangential inlet. The study was performed for gas-solid flow, based on an experimental study available in the literature, where a conventional cyclone model was used. Numerical experiments were performed by using CFX 5.7.1. The axial and tangential velocity components were evaluated using RSM and LES turbulence models. Results showed that these new designs can improve the cyclone performance parameters significantly and very interesting details were found on cyclone fluid dynamics properties using RSM and LES.
Optimal Design of Measurement Programs for the Parameter Identification of Dynamic Systems
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune
The design of measurement programs devoted to parameter identification of structural dynamic systems is considered. The design problem is formulated as an optimization problem to minimize the total expected cost that is the cost of failure and the cost of the measurement program. All the calculat...... for estimating the modal damping parameters in a simply supported plane, vibrating beam model. Results show optimal number of sensors and their locations....... the calculations are based on a priori knowledge and engineering judgement. One of the contribution of the approach is that the optimal number of sensors can be estimated. This is shown in a numerical example where the proposed approach is demonstrated. The example is concerned with design of a measurement program...
Institute of Scientific and Technical Information of China (English)
ZHOV Nian-qing; ZHAO Zai-li; QIN Min
2009-01-01
The earthquake characteristics and geological structure of the site to sitting the Qinshan Nuclear Power Station are closely related. According to site investigation drilling, sampling, seismic sound logging wave test in single-hole and cross-hole, laboratory wave velocity test of intact rock, together with analysis of the site geological conditions, the seismic wave test results of the site between strata lithology and the geologic structure were studied. The relationships of seismic waves with the site lithology and the geologic structure were set up.The dynamic parameters of different grades of weathering profile were deduced. The results assist the seismic design of Phase Ⅲ Qinshan Nuclear Power Plant, China.
Lax representation of the hyperbolic van Diejen dynamics with two coupling parameters
Pusztai, B G
2016-01-01
In this paper, we construct a Lax pair for the classical hyperbolic van Diejen system with two independent coupling parameters. Built upon this construction, we show that the dynamics can be solved by a projection method, which in turn allows us to initiate the study of the scattering properties. As a consequence, we prove the equivalence between the first integrals provided by the eigenvalues of the Lax matrix and the family of van Diejen's commuting Hamiltonians. Also, at the end of the paper, we propose a candidate for the Lax matrix of the hyperbolic van Diejen system with three independent coupling constants.
Existence of positive solutions for nonlinear dynamic systems with a parameter on a measure chain
Directory of Open Access Journals (Sweden)
Shuang-Hong Ma
2007-05-01
Full Text Available In this paper, we consider the following dynamic system with parameter on a measure chain $mathbb{T}$, $$displaylines{ u^{DeltaDelta}_{i}(t+lambda h_{i}(tf_{i}(u_{1}(sigma(t, u_{2}(sigma(t,dots ,u_{n}(sigma(t=0,quad tin[a,b], cr alpha u_{i}(a-eta u^{Delta}_{i}(a=0,quad gamma u_{i}(sigma(b+delta u^{Delta}_{i}(sigma(b=0, }$$ where $i=1,2,dots ,n$. Using fixed-point index theory, we find sufficient conditions the existence of positive solutions.
On-line parameter and delay estimation of continuous-time dynamic systems
Directory of Open Access Journals (Sweden)
Kozłowski Janusz
2015-06-01
Full Text Available The problem of on-line identification of non-stationary delay systems is considered. The dynamics of supervised industrial processes are usually modeled by ordinary differential equations. Discrete-time mechanizations of continuous-time process models are implemented with the use of dedicated finite-horizon integrating filters. Least-squares and instrumental variable procedures mechanized in recursive forms are applied for simultaneous identification of input delay and spectral parameters of the system models. The performance of the proposed estimation algorithms is verified in an illustrative numerical simulation study.
Dynamic response of carbon nanotube field-effect transistors analyzed by S-parameters measurement
Energy Technology Data Exchange (ETDEWEB)
Bethoux, J.-M. [Institut d' Electronique, de Microelectronique et de Nanotechnologie, C.N.R.S. U.M.R. 8520, BP 60069, F-59652, Villeneuve d' Ascq Cedex (France); Happy, H. [Institut d' Electronique, de Microelectronique et de Nanotechnologie, C.N.R.S. U.M.R. 8520, BP 60069, F-59652, Villeneuve d' Ascq Cedex (France)]. E-mail: henri.happy@iemn.univ-lille1.fr; Dambrine, G. [Institut d' Electronique, de Microelectronique et de Nanotechnologie, C.N.R.S. U.M.R. 8520, BP 60069, F-59652, Villeneuve d' Ascq Cedex (France); Derycke, V. [Laboratoire d' Electronique Moleculaire, SPEC, Commissariat a l' Energie Atomique, Saclay F-91191, Gif sur Yvette Cedex (France); Goffman, M. [Laboratoire d' Electronique Moleculaire, SPEC, Commissariat a l' Energie Atomique, Saclay F-91191, Gif sur Yvette Cedex (France); Bourgoin, J.-P. [Laboratoire d' Electronique Moleculaire, SPEC, Commissariat a l' Energie Atomique, Saclay F-91191, Gif sur Yvette Cedex (France)
2006-12-15
Carbon nanotube field-effect transistors (CN-FET) with a metallic back gate have been fabricated. By assembling a number of CNs in parallel, driving currents in the mA range have been obtained. The dynamic response of the CN-FETs has been investigated through S-parameters measurements. A current gain (|H {sub 21}|{sup 2}) cut-off frequency (f {sub t}) of 8 GHz, and a maximum stable gain (MSG) value of 10 dB at 1 GHz have been obtained. The extraction of an equivalent circuit is proposed.
Classical Order Parameter Dynamics and the Decay of a Metastable Vacuum State
Szép, Z
2000-01-01
Transition of the ground state of a classical $\\Phi^4$ theory in 2+1 dimensions is studied from a metastable state into the stable equilibrium. The transition occurs in the broken $Z_2$ symmetry phase and is triggered by a vanishingly small amplitude homogeneous external field $h$. A phenomenological theory is proposed in form of an effective equation of the quantitatively accounts for the decay of the false vacuum. The large amplitude transition of the order parameter between the two minima displays characteristics reflecting dynamical aspects of the Maxwell construction.
Suminar, Wulan; Saepuloh, Asep; Meilano, Irwan
2016-05-01
Analysis of hazard assessment to active volcanoes is crucial for risk management. The hazard map of volcano provides information to decision makers and communities before, during, and after volcanic crisis. The rapid and accurate hazard assessment, especially to an active volcano is necessary to be developed for better mitigation on the time of volcanic crises in Indonesia. In this paper, we identified the hazard parameters to develop quantitative and dynamic hazard map of an active volcano. The Guntur volcano in Garut Region, West Java, Indonesia was selected as study area due population are resided adjacent to active volcanoes. The development of infrastructures, especially related to tourism at the eastern flank from the Summit, are growing rapidly. The remote sensing and field investigation approaches were used to obtain hazard parameters spatially. We developed a quantitative and dynamic algorithm to map spatially hazard potential of volcano based on index overlay technique. There were identified five volcano hazard parameters based on Landsat 8 and ASTER imageries: volcanic products including pyroclastic fallout, pyroclastic flows, lava and lahar, slope topography, surface brightness temperature, and vegetation density. Following this proposed technique, the hazard parameters were extracted, indexed, and calculated to produce spatial hazard values at and around Guntur Volcano. Based on this method, the hazard potential of low vegetation density is higher than high vegetation density. Furthermore, the slope topography, surface brightness temperature, and fragmental volcanic product such as pyroclastics influenced to the spatial hazard value significantly. Further study to this proposed approach will be aimed for effective and efficient analyses of volcano risk assessment.
Directory of Open Access Journals (Sweden)
Jessica H Farley
Full Text Available Knowledge of spawning behaviour and fecundity of fish is important for estimating the reproductive potential of a stock and for constructing appropriate statistical models for assessing sustainable catch levels. Estimates of length-based reproductive parameters are particularly important for determining potential annual fecundity as a function of fish size, but they are often difficult to estimate reliably. Here we provide new information on the reproductive dynamics of southern bluefin tuna (SBT Thunnus maccoyii through the analysis of fish size and ovary histology collected on the spawning ground in 1993-1995 and 1999-2002. These are used to refine previous parameter estimates of spawning dynamics and investigate size related trends in these parameters. Our results suggest that the small SBT tend to arrive on the spawning ground slightly later and depart earlier in the spawning season relative to large fish. All females were mature and the majority were classed as spawning capable (actively spawning or non-spawning with a very small proportion classed as regressing. The fraction of females spawning per day decreased with fish size, but once females start a spawning episode, they spawned daily irrespective of size. Mean batch fecundity was estimated directly at 6.5 million oocytes. Analysis of ovary histology and ovary weight data indicated that relative batch fecundity, and the duration of spawning and non-spawning episodes, increased with fish size. These reproductive parameter estimates could be used with estimates of residency time on the spawning ground as a function of fish size (if known and demographic data for the spawning population to provide a time series of relative annual fecundity for SBT.
Directory of Open Access Journals (Sweden)
Vipa Thanachartwet
Full Text Available Few previous studies have monitored hemodynamic parameters to determine the physiological process of dengue or examined inferior vena cava (IVC parameters to assess cardiac preload during the clinical phase of dengue. From January 2013 to July 2015, we prospectively studied 162 hospitalized adults with confirmed dengue viral infection using non-invasive cardiac output monitoring and bedside ultrasonography to determine changes in hemodynamic and IVC parameters and identify the types of circulatory shock that occur in patients with dengue. Of 162 patients with dengue, 17 (10.5% experienced dengue shock and 145 (89.5% did not. In patients with shock, the mean arterial pressure was significantly lower on day 6 after fever onset (P = 0.045 and the pulse pressure was significantly lower between days 4 and 7 (P50% between days 4 and 5 (P<0.05. Hypovolemic shock was observed in 9 (52.9% patients and cardiogenic shock in 8 (47.1%, with a median (interquartile range time to shock onset of 6.0 (5.0-6.5 days after fever onset, which was the median day of defervescence. Intravascular hypovolemia occurred before defervescence, whereas myocardial dysfunction occurred on the day of defervescence until 2 weeks after fever onset. Hypovolemic shock and cardiogenic shock each occurred in approximately half of the patients with dengue shock. Therefore, dynamic measures to estimate changes in hemodynamic parameters and preload should be monitored to ensure adequate fluid therapy among patients with dengue, particularly patients with dengue shock.
Monitor of dynamic parameters in real time; Monitor de parametros dinamicos en tiempo real
Energy Technology Data Exchange (ETDEWEB)
Rojas S, A.S.; Ruiz E, J.A. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)
2008-07-01
In the complex physical systems exist parameters that are necessary for monitoring in real time. In the nuclear industry, particularly in a reactor this surveillance is important, where the times of the reactions are almost instantaneous. Although many of these parameters are monitored, given the advance of the computer systems the monitoring could either be enlarged direct or indirect of other parameters. The analysis of the neutron noise in the nuclear reactors, plays an important role, the noise signal it contains information about the operation conditions of a system, when analyzing it with analysis methodologies of analogical signals to provide important information for the early detection of possible flaws and to indicate the permissible operation levels. To show the characteristics of the operation of the system of Monitoring of Dynamic Parameters in Real Time, oscillations of neutron noise of the TRIGA Mark III of the ININ were analyzed, these were caused with the control bar to a power of 10 Watts, the oscillations were carried out to a frequency of 1Hz, signal of low frequency. In this work a virtual instrument that allows by means of the spectral analysis method in frequency point by point is presented, to indicate in real time periodic variations that could be presented in the neutron noise signal, visualizing in advance the dynamic behavior of the system or nuclear plant. Another of the tests of the monitoring system presented is that of the oscillatory event happened in the reactor of Laguna Verde Nucleo electric Central, would be convenient to have an instrument of surveillance for monitoring through the neutron noise signal the behavior of some important parameter to predict and to indicate in an immediate way an abnormal condition in the reactor operation or in the plant system. These parameters can be the power, the recirculation water flow, etc. The monitor is based on a personal computer (PC), a data acquisition card (ADC) and a computer program
RESEARCH OF DYNAMIC PARAMETERS OF THE ELECTRIC DRIVE ON THE BASIS OF ROLLING ROTOR MOTOR
Directory of Open Access Journals (Sweden)
G. V. Kulinchenko
2016-12-01
Full Text Available Purpose. Development and investigation of a dynamic model of electric drive on the base of the rolling rotor motor (RRM which reflects the positioning of the actuator of the locking and regulating equipment in time. Methodology. Analytical description of electromagnetic and mechanical processes in the electric drive during the RRM shaft movement by using a system of differential equations. Numerical imitation modeling with the processes visualization in the Matlab environment of the RRM rotor displacement with mechanical load in time. Results. It is shown that the degree of influence of the value of the load inertia on the dynamics of the object obtained by the waveform changes the rotation angle of the rotor and motor speed in time. The degree of influence of the value of the electromagnetic time constant of the dynamics of the positioning of the actuator, and the nature of transients during acceleration and fixing position of the rotor with a predetermined moment of inertia for different values of inductance. The effect of the ratio of electromechanical and electromagnetic time constants of the nature of the transition processes accompanying jog mode angular displacement of the drive shaft on the base of RRM. Originality. The lack of technical means to ensure acceptable accuracy time measurement of angular displacement shaft of the actuator in jog mode offset by using a laser meter which gives the opportunity to assess the adequacy of the dynamic model of the RRM. Practical value. The results of investigations allow to create a tool for optimization of structural, technical and hardware and software solutions for the improvement and modernization of the projected electric locking and regulating equipment. The direction for improving the dynamics of the drive on the basis of RRM is indicated providing for an increase in its torque characteristics of the motor by reducing the influence of the parameters of transients.
Relativistic two-body bound states in scalar QFT: variational basis-state approach
Energy Technology Data Exchange (ETDEWEB)
Emami-Razavi, Mohsen [Centre for Research in Earth and Space Science, York University, Toronto, Ontario, M3J 1P3 (Canada); Darewych, Jurij W [Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3 (Canada)
2006-08-15
We use the Hamiltonian formalism of quantum field theory and the variational basis-state method to derive relativistic coupled-state wave equations for scalar particles interacting via a massive or massless mediating scalar field (the scalar Yukawa model). A variational trial state comprised of two and four Fock-space states is used to derive coupled wave equations for a relativistic two (and four) body system. Approximate, variational two-body ground-state solutions of the relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields. The results show that the inclusion of virtual pairs has a large effect on the two-body binding energy at strong coupling. A comparison of the two-body binding energies with other calculations is presented.
Zhao, Jing-Shan; Li, Lingyang; Chen, Liping; Zhang, Yunqing
2010-12-01
This paper starts with a classical mechanism synthesis problem and focuses on the concept design and dynamics analysis of an independent suspension that has invariable orientation parameters when the wheel moves up (jounces) and down (rebounds). The paper first proposes a symmetric redundant constraint suspension structure that has invariable orientation parameters. And then, it analyses the mechanism mobility with the reciprocal screw theory, after which it establishes the displacement constraint equations of the suspension. This type of suspension has all the advantages of the sliding pillar suspension but overcomes its disadvantage of over-wearing. Through differentiating the constraint equations with respect to time, it obtains the kinematics relationship and builds up the dynamics equations of the suspension via Newton-Euler method. Numerical simulations indicate that this kind of independent suspensions should not only eliminate the shambling shocks induced by the jumping of wheels but also decrease the abrasion of the wheels. Therefore, this kind of independent suspensions can obviously improve the ride and handling properties of advanced automobiles.
Effect Analysis of Vehicle System Parameters on Dynamic Response of Pavement
Directory of Open Access Journals (Sweden)
Rong-xia Xia
2015-01-01
Full Text Available In order to study the damage of a semirigid pavement under vehicle loads with varied parameters, the random dynamic loads applied on the pavement by a running vehicle were computed with two degrees of freedom, quarter-vehicle model, and then a three-dimensional finite element analysis model of semirigid asphalt pavement was established. With the peak stress index of each pavement layer, the effect of varied vehicle parameters on pavement response was studied. The results indicated that the stress wave frequency of each pavement layer was similar to that of the dynamic random load, and, with increased pavement depth, the wave effect decreased. The pavement response increased with increased suspension stiffness and tire stiffness and decreased with increased suspension damping and tire damping. Furthermore, compared to the stiffness, the response variation induced by the damping was orders of magnitude lower. Compared with the traditional time response analysis method, the peak response analysis of the pavement structure was more scientific, rational, and intuitive, which could be useful for the study of vehicle-pavement interaction and road damage.
Spin Structure of Many-Body Systems with Two-Body Random Interactions
Kaplan, L; Johnson, C W; Kaplan, Lev; Papenbrock, Thomas; Johnson, Calvin W.
2001-01-01
We investigate the spin structure of many-fermion systems with a spin-conserving two-body random interaction. We find a strong dominance of spin-0 ground states and considerable correlations between energies and wave functions of low-lying states with different spin, but no indication of pairing. The spectral densities exhibit spin-dependent shapes and widths, and depend on the relative strengths of the spin-0 and spin-1 couplings in the two-body random matrix. The spin structure of low-lying states can largely be explained analytically.
Exact two-body solutions and quantum defect theory of two-dimensional dipolar quantum gas
Jie, Jianwen; Qi, Ran
2016-10-01
In this paper, we provide the two-body exact solutions of the two-dimensional (2D) Schrödinger equation with isotropic +/- 1/{r}3 interactions. An analytic quantum defect theory is constructed based on these solutions and it is applied to investigate the scattering properties as well as two-body bound states of an ultracold polar molecules confined in a quasi-2D geometry. Interestingly, we find that for the attractive case, the scattering resonance happens simultaneously in all partial waves, which has not been observed in other systems. The effect of this feature on the scattering phase shift across such resonances is also illustrated.
Analytical expressions for partial wave two-body Coulomb transition matrices at ground-state energy
Kharchenko, V. F.
2016-11-01
Leaning upon the Fock method of the stereographic projection of the three-dimensional momentum space onto the four-dimensional unit sphere the possibility of the analytical solving of the Lippmann-Schwinger integral equation for the partial wave two-body Coulomb transition matrix at the ground bound state energy has been studied. In this case new expressions for the partial p-, d- and f-wave two-body Coulomb transition matrices have been obtained in the simple analytical form. The developed approach can also be extended to determine analytically the partial wave Coulomb transition matrices at the energies of excited bound states.
Neutral weak-current two-body contributions in inclusive scattering from {sup 12}C
Energy Technology Data Exchange (ETDEWEB)
Lovato, Alessandro [ANL; Gandolfi, Stefano [LANL; Carlson, Joseph [LANL; Pieper, S. C. [ANL; Schiavilla, Rocco [JLAB, ODU
2014-05-01
An {\\it ab initio} calculation of the sum rules of the neutral weak response functions in $^{12}$C is reported, based on a realistic Hamiltonian, including two- and three-nucleon potentials, and on realistic currents, consisting of one- and two-body terms. We find that the sum rules of the response functions associated with the longitudinal and transverse components of the (space-like) neutral current are largest and that a significant portion ($\\simeq 30$\\%) of the calculated strength is due to two-body terms. This fact may have implications for the MiniBooNE and other neutrino quasi-elastic scattering data on nuclei.
Piovesan, Davide; Pierobon, Alberto; Dizio, Paul; Lackner, James R
2011-03-01
A common problem in the analyses of upper limb unfettered reaching movements is the estimation of joint torques using inverse dynamics. The inaccuracy in the estimation of joint torques can be caused by the inaccuracy in the acquisition of kinematic variables, body segment parameters (BSPs), and approximation in the biomechanical models. The effect of uncertainty in the estimation of body segment parameters can be especially important in the analysis of movements with high acceleration. A sensitivity analysis was performed to assess the relevance of different sources of inaccuracy in inverse dynamics analysis of a planar arm movement. Eight regression models and one water immersion method for the estimation of BSPs were used to quantify the influence of inertial models on the calculation of joint torques during numerical analysis of unfettered forward arm reaching movements. Thirteen subjects performed 72 forward planar reaches between two targets located on the horizontal plane and aligned with the median plane. Using a planar, double link model for the arm with a floating shoulder, we calculated the normalized joint torque peak and a normalized root mean square (rms) of torque at the shoulder and elbow joints. Statistical analyses quantified the influence of different BSP models on the kinetic variable variance for given uncertainty on the estimation of joint kinematics and biomechanical modeling errors. Our analysis revealed that the choice of BSP estimation method had a particular influence on the normalized rms of joint torques. Moreover, the normalization of kinetic variables to BSPs for a comparison among subjects showed that the interaction between the BSP estimation method and the subject specific somatotype and movement kinematics was a significant source of variance in the kinetic variables. The normalized joint torque peak and the normalized root mean square of joint torque represented valuable parameters to compare the effect of BSP estimation methods
Páez, Rocío Isabel; Efthymiopoulos, Christos
2015-02-01
The possibility that giant extrasolar planets could have small Trojan co-orbital companions has been examined in the literature from both viewpoints of the origin and dynamical stability of such a configuration. Here we aim to investigate the dynamics of hypothetical small Trojan exoplanets in domains of secondary resonances embedded within the tadpole domain of motion. To this end, we consider the limit of a massless Trojan companion of a giant planet. Without other planets, this is a case of the elliptic restricted three body problem (ERTBP). The presence of additional planets (hereafter referred to as the restricted multi-planet problem, RMPP) induces new direct and indirect secular effects on the dynamics of the Trojan body. The paper contains a theoretical and a numerical part. In the theoretical part, we develop a Hamiltonian formalism in action-angle variables, which allows us to treat in a unified way resonant dynamics and secular effects on the Trojan body in both the ERTBP or the RMPP. In both cases, our formalism leads to a decomposition of the Hamiltonian in two parts, . , called the basic model, describes resonant dynamics in the short-period (epicyclic) and synodic (libration) degrees of freedom, while contains only terms depending trigonometrically on slow (secular) angles. is formally identical in the ERTBP and the RMPP, apart from a re-definition of some angular variables. An important physical consequence of this analysis is that the slow chaotic diffusion along resonances proceeds in both the ERTBP and the RMPP by a qualitatively similar dynamical mechanism. We found that this is best approximated by the paradigm of `modulational diffusion'. In the paper's numerical part, we then focus on the ERTBP in order to make a detailed numerical demonstration of the chaotic diffusion process along resonances. Using color stability maps, we first provide a survey of the resonant web for characteristic mass parameter values of the primary, in which the
Energy Technology Data Exchange (ETDEWEB)
Kaspi, Yohai [Department of Earth and Planetary Sciences, Weizmann Institute of Science, 234 Herzl st., 76100, Rehovot (Israel); Showman, Adam P., E-mail: yohai.kaspi@weizmann.ac.il [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States)
2015-05-01
The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.
Similitude of ice dynamics against scaling of geometry and physical parameters
Feldmann, Johannes; Levermann, Anders
2016-08-01
The concept of similitude is commonly employed in the fields of fluid dynamics and engineering but rarely used in cryospheric research. Here we apply this method to the problem of ice flow to examine the dynamic similitude of isothermal ice sheets in shallow-shelf approximation against the scaling of their geometry and physical parameters. Carrying out a dimensional analysis of the stress balance we obtain dimensionless numbers that characterize the flow. Requiring that these numbers remain the same under scaling we obtain conditions that relate the geometric scaling factors, the parameters for the ice softness, surface mass balance and basal friction as well as the ice-sheet intrinsic response time to each other. We demonstrate that these scaling laws are the same for both the (two-dimensional) flow-line case and the three-dimensional case. The theoretically predicted ice-sheet scaling behavior agrees with results from numerical simulations that we conduct in flow-line and three-dimensional conceptual setups. We further investigate analytically the implications of geometric scaling of ice sheets for their response time. With this study we provide a framework which, under several assumptions, allows for a fundamental comparison of the ice-dynamic behavior across different scales. It proves to be useful in the design of conceptual numerical model setups and could also be helpful for designing laboratory glacier experiments. The concept might also be applied to real-world systems, e.g., to examine the response times of glaciers, ice streams or ice sheets to climatic perturbations.
Directory of Open Access Journals (Sweden)
Deepti Sharma
2016-12-01
Full Text Available Web application is being challenged to develop methods and techniques for large data processing at optimum response time. There are technical challenges in dealing with the increasing demand to handle vast traffic on these websites. As number of users‟ increases, several problems are faced by web servers like bottleneck, delayed response time, load balancing and density of services. The whole traffic cannot reside on a single server and thus there is a fundamental requirement of allocating this huge traffic on multiple load balanced servers. Distributing requests among servers in the web server clusters is the most important means to address such challenge, especially under intense workloads. In this paper, we propose a new request distribution algorithm for load balancing among web server clusters. The Dynamic Load Balancing among web servers take place based on user‟s request and dynamically estimating server workload using multiple parameters like processing and memory requirement, expected execution time and various time intervals. Our simulation results show that, the proposed method dynamically and efficiently balance the load to scale up the services, calculate average response time, average waiting time and server‟s throughput on different web servers. At the end of the paper, we presented an experimentation of running proposed system which proves the proposed algorithm is effic ient in terms of speed of processing, response time, server utilization and cost efficiency
Robust control and linear parameter varying approaches application to vehicle dynamics
Gaspar, Peter; Bokor, József
2013-01-01
Vehicles are complex systems (non-linear, multi-variable) where the abundance of embedded controllers should ensure better security. This book aims at emphasizing the interest and potential of Linear Parameter Varying methods within the framework of vehicle dynamics, e.g. · proposed control-oriented model, complex enough to handle some system non linearities but still simple for control or observer design, · take into account the adaptability of the vehicle's response to driving situations, to the driver request and/or to the road sollicitations, · manage interactions between various actuators to optimize the dynamic behavior of vehicles. This book results from the 32th International Summer School in Automatic that held in Grenoble, France, in September 2011, where recent methods (based on robust control and LPV technics), then applied to the control of vehicle dynamics, have been presented. After some theoretical background and a view on so...
Directory of Open Access Journals (Sweden)
Mihai ISPAS
2015-12-01
Full Text Available Pre-laminated (coated particleboards (PB are wood-based composites intensively used in the furniture industry. In order to prepare the PB for joining, drilling is the most commonly applied machining process. The surface quality and the dynamic parameters (thrust force and torque are significantly influenced by the tools characteristics and the machining parameters. The point/tip angle of the drill bit and the feed speed during drilling play a major role in gaining a good surface quality and minimizing the dynamic parameters. The objective of this study was to measure and analyze the influence of both the geometric and cinematic parameters on the dynamic parameters at drilling with twist (helical drills. The experiments were performed based on a factorial design. The results show that, a low feed rate generally minimizes both the drilling torque and the thrust force, while a small tip angle increases the drilling torque and minimizes the thrust force.
Jensen, Benjamin D; Bandyopadhyay, Ananyo; Wise, Kristopher E; Odegard, Gregory M
2012-09-11
The development of innovative carbon-based materials can be greatly facilitated by molecular modeling techniques. Although the Reax Force Field (ReaxFF) can be used to simulate the chemical behavior of carbon-based systems, the simulation settings required for accurate predictions have not been fully explored. Using the ReaxFF, molecular dynamics (MD) simulations are used to simulate the chemical behavior of pure carbon and hydrocarbon reactive gases that are involved in the formation of carbon structures such as graphite, buckyballs, amorphous carbon, and carbon nanotubes. It is determined that the maximum simulation time step that can be used in MD simulations with the ReaxFF is dependent on the simulated temperature and selected parameter set, as are the predicted reaction rates. It is also determined that different carbon-based reactive gases react at different rates, and that the predicted equilibrium structures are generally the same for the different ReaxFF parameter sets, except in the case of the predicted formation of large graphitic structures with the Chenoweth parameter set under specific conditions.
Belmares, M; Blanco, M; Goddard, W A; Ross, R B; Caldwell, G; Chou, S-H; Pham, J; Olofson, P M; Thomas, Cristina
2004-11-30
We introduce the Cohesive Energy Density (CED) method, a multiple sampling Molecular Dynamics computer simulation procedure that may offer higher consistency in the estimation of Hildebrand and Hansen solubility parameters. The use of a multiple sampling technique, combined with a simple but consistent molecular force field and quantum mechanically determined atomic charges, allows for the precise determination of solubility parameters in a systematic way (sigma = 0.4 hildebrands). The CED method yields first-principles Hildebrand parameter predictions in good agreement with experiment [root-mean-square (rms) = 1.1 hildebrands]. We apply the CED method to model the Caltech electronic nose, an array of 20 polymer sensors. Sensors are built with conducting leads connected through thin-film polymers loaded with carbon black. Odorant detection relies on a change in electric resistivity of the polymer film as function of the amount of swelling caused by the odorant compound. The amount of swelling depends upon the chemical composition of the polymer and the odorant molecule. The pattern is unique, and unambiguously identifies the compound. Experimentally determined changes in relative resistivity of seven polymer sensors upon exposure to 24 solvent vapors were modeled with the CED estimated Hansen solubility components. Predictions of polymer sensor responses result in Pearson R2 coefficients between 0.82 and 0.99.
Energy Technology Data Exchange (ETDEWEB)
Tunc Aldemir; Don W. Miller; Brian k. Hajek; Peng Wang
2002-04-01
The DSD (Dynamic System Doctor) is a system-independent, interactive software under development for on-line state/parameter estimation in dynamic systems (1), partially supported through a Nuclear Engineering Education (NEER) grant during 1998-2001. This paper summarizes the recent accomplishments in improving the user-friendliness and computational capability of DSD
RANS Simulation of the Heave Response of a Two-Body Floating Point Wave Absorber: Preprint
Energy Technology Data Exchange (ETDEWEB)
Yu, Y.; Li, Y.
2011-03-01
A preliminary study on a two-body floating wave absorbers is presented in this paper. A Reynolds-Averaged Navier-Stokes computational method is applied for analyzing the hydrodynamic heave response of the absorber in operational wave conditions. The two-body floating wave absorber contains a float section and a submerged reaction section. For validation purposes, our model is first assumed to be locked. The two sections are forced to move together with each other. The locked single body model is used in a heave decay test, where the RANS result is validated with the experimental measurement. For the two-body floating point absorber simulation, the two sections are connected through a mass-spring-damper system, which is applied to simulate the power take-off mechanism under design wave conditions. Overall, the details of the flow around the absorber and its nonlinear interaction with waves are investigated, and the power absorption efficiency of the two-body floating wave absorber in waves with a constant value spring-damper system is examined.
Realization of the Fredkin gate using a series of one- and two-body operators
Chau, H F; Chau, Hoi Fung; Wilczek, F
1995-01-01
The Fredkin 3-bit gate is universal for computational logic, and is reversible. Classically, it is impossible to do universal computation using reversible 2-bit gates only. Here we construct the Fredkin gate using a combination of two one-body and seven two-body reversible (quantum) operators.
Computation of Two-Body Matrix Elements From the Argonne $v_{18}$ Potential
Mihaila, B; Mihaila, Bogdan; Heisenberg, Jochen H.
1998-01-01
We discuss the computation of two-body matrix elements from the Argonne $v_{18}$ interaction. The matrix elements calculation is presented both in particle-particle and in particle-hole angular momentum coupling. The procedures developed here can be applied to the case of other NN potentials, provided that they have a similar operator format.
Two-body depolarized cils spectra of krypton and xenon at 295 K
Zoppi, M.; Moraldi, M.; Barocchi, F.; Magli, R.; Bafile, U.
1981-10-01
We have experimentally determined the two-body depolarized CILS spectra of krypton and xenon at room temperature between 2 and 120 cm-1. Comparison of the first three even experimental moments of the spectra with theoretical calculations shows, as in argon, the necessity of introducing a short-range negative contribution to the induced pair polarizability.
78 FR 54756 - Extension of Expiration Dates for Two Body System Listings
2013-09-06
... ADMINISTRATION 20 CFR Part 404 RIN 0960-AH60 Extension of Expiration Dates for Two Body System Listings AGENCY: Social Security Administration. ACTION: Final rule. SUMMARY: We are extending the expiration dates of the... claims and continuing disability reviews. DATES: This final rule is effective on September 6, 2013....
Searching for new physics in two-body decays: Ideas and pitfalls
Arrieta Diaz, E; Büchler, A; Cieri, L J; Florez, A; Garces-Garcia, E; Gonçalves, B; Koetsveld, F; Leney, K J C; Marquez Falcon, H; Moncada, M; Quintero, P; Romero, D; Shaw, K; Swain, J; Zurita, M P
2010-01-01
Many new physics processes, and indeed many Standard Model interactions involve two-body decays. Although the kinematics are relatively simple, mistakes can easily be made when applying cuts to data in order to separate the signal from backgrounds. We present a short, but relevant list of possible sources of errors, and discuss the consequences of these.
Dynamic Changes of the CT Perfusion Parameters in the Embolic Model of Cerebral Ischemia
Institute of Scientific and Technical Information of China (English)
陈唯唯; 漆剑频; 张进华; 黄文华; 宋金梅
2004-01-01
To study the dynamic changes of CT perfusion parameters during the first 12 h in the embolic cerebral ischemia models. Local cerebral ischemia model were established in 7 New Zealand white rabbits. All CT scans were performed with a GE Lightspeed 16 multislice CT. Following the baseline scan, further CT perfusion scans were performed at the same locations 20 min, 1-6 h and8, 10 and 12 h after the embolus delivery. Maps of all parameters were obtained by CT perfusion software at each time point. The brains, taken 12 h after the scan, were sliced corresponding to the positions of the CT slices and stained by 2,3,5-triphenyltetrazolium chloride (TTC). On the basis of the TTC results, the ischemicsides were divided into 3 regions: core, penumbra and the relatively normal region. The changes of all parameters were then divided into 3 stages. In the first two hours (the first stage), the CBV dropped more remarkably in the core than in the penumbra but rose slightly in the relatively normal region while the CBF decreased and MTT, TTP extended in all regions to varying degrees. In the 2nd-5th h (the second stage), all the parameters fluctuated slightly around a certain level. In the 5th-12th h (the third stage), the CBV and CBF dropped,and MTT and TTP were prolonged or shortened slightly in the core and penumbra though much notably in the former while the CBV, CBF roseand MTT, TTP were shortened remarkably in the relatively normal region. We experimentally demonstrated that the location and extent of cerebral ischemia could be accurately assessed by CT perfusion imaging. The pathophysiology of the ischemia could be reflected by the CT perfusion to varying degrees.
Directory of Open Access Journals (Sweden)
L. Pretorius
2012-01-01
Full Text Available
ENGLISH ABSTRACT: Technology can be identified as the result of an innovation process that may be time-dependent. Furthermore, technology is both an input to the innovation process and an output of it. When two competing technologies are diffused into the market, they are evaluated as a technology system by means of a systems dynamics approach. It is shown that systems thinking can be used initially to identify and assess the important factors that influence the competitive behaviour of the two technologies. Interesting dynamics of this technology management system are presented and discussed in the context of uncertainty of interaction between the two technologies. It is specifically shown that the life span of the existing technology, which resists competition, may be adversely affected under conditions of uncertainty. The effect of uncertainty in more than one systems dynamics model parameter – specifically, the interaction and market parameter in the competing technology system – is also addressed. The Lotka-Volterra approach of predator-prey interaction is used to model the interaction between and diffusion of the two technologies in the system. A qualitative assessment of the systems dynamics model without uncertainty is attempted in the exploration of a real case study of two competing technologies.
AFRIKAANSE OPSOMMING: DTegnologie kan beskryf word as die resultaat van ’n innovasie proses wat tydsveranderlik kan wees. Tegnologie is beide ’n inset sowel as ’n uitset van die innovasie proses. ’n Geval waar twee kompeterende tegnologieë in die mark diffundeer word met behulp van sisteemdinamika geëvalueer as ’n tegnologiestelsel. Dit word aangetoon dat stelselsdenke gebruik kan word as voorloper om die belangrike faktore wat die kompeterende gedrag van die twee tegnologieë beïnvloed, te identifiseer en te assesseer. Interessante dinamiese gedrag van hierdie tegnologiebestuurstelsel word aangebied en bespreek in
Lee, C.-H.; Herget, C. J.
1976-01-01
This short paper considers the parameter-identification problem of general discrete-time, nonlinear, multiple input-multiple output dynamic systems with Gaussian white distributed measurement errors. Knowledge of the system parameterization is assumed to be available. Regions of constrained maximum likelihood (CML) parameter identifiability are established. A computation procedure employing interval arithmetic is proposed for finding explicit regions of parameter identifiability for the case of linear systems.
Inverse dynamics and servomotor parameter estimation of a 2-DOF spherical parallel mechanism
Institute of Scientific and Technical Information of China (English)
D; G; CHETWYND
2008-01-01
A novel reconfigurable 5-DOF hybrid manipulator―TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limb- stroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper, on the basis of inverse dynamic formula- tion of the 2-DOF spherical parallel mechanism, an approach is proposed for esti- mating the servomotor parameters including moment of inertia, rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.
Inverse dynamics and servomotor parameter estimation of a 2-DOF spherical parallel mechanism
Institute of Scientific and Technical Information of China (English)
LIU HaiTao; MEI JiangPing; ZHAO XueMan; HUANG Tian; D G CHETWYND
2008-01-01
A novel reconfigurable 5-DOF hybrid manipulator - TriVariant-B is composed of a 2-DOF spherical parallel mechanism which is serially connected with a 3-DOF open-loop kinematic chain undergoing one translation and two rotations by a prismatic joint. The merit of this design is that a relatively large workspace/limbstroke ratio can be achieved thanks to the decomposition of the fixed point rotation and the relative translation. In this paper,on the basis of inverse dynamic formulation of the 2-DOF spherical parallel mechanism,an approach is proposed for estimating the servomotor parameters including moment of inertia,rated speed and the maximum torque in a quick manner. The approach has been employed for the development of a prototype for frame cutting process.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Guanglei, E-mail: guangleizhang@bjtu.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044 (China); Pu, Huangsheng; Liu, Fei; Bai, Jing [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); He, Wei [China Institute of Sport Science, Beijing 100061 (China); Luo, Jianwen, E-mail: luo-jianwen@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing 100084 (China)
2015-02-23
Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.
Multi-Parameter Signal Sorting Algorithm Based on Dynamic Distance Clustering
Institute of Scientific and Technical Information of China (English)
Ai-Ling He; De-Guo Zeng; Jun Wang; Bin Tang
2009-01-01
A multi-parameter signal sorting algo- rithm for interleaved radar pulses in dense emitter environment is presented. The algorithm includes two parts, pulse classification and pulse repetition interval (PRI) analysis. Firstly, we propose the dynamic distance clustering (DDC) for classification. In the clustering algorithm, the multi-dimension features of radar pulse are used for reliable classification. The similarity threshold estimation method in DDC is derived, which contributes to the efficiency of the algorithm. However, DDC has large computation with many signal pulses. Then, in order to sort radar signals in real time, the improved DDC (IDDC) algorithm is proposed. Finally, PRI analysis is adopted to complete the process of sorting. The simulation experiments and hardware implementations show both algorithms are effective.
Xu, Yuanping; Zhou, Jin; Di, Long; Zhao, Chen
2017-01-01
Active magnetic bearings (AMBs) support rotors using electromagnetic force rather than mechanical forces. It is necessary to accurately identify the AMBs force coefficients since they play a critical role in the rotordynamic analysis including system stability, bending critical speeds and modes of vibrations. This paper proposes a rotor unbalance response based approach to identifying the AMBs stiffness and damping coefficients during rotation. First, a Timoshenko beam finite element (FE) rotor model is created. Second, an identification procedure based on the FE model is proposed. Then based on the experimental rotor unbalance response data from 1200 rpm to 30,000 rpm, the AMBs dynamic force parameters (stiffness and damping) are obtained. Finally, the identified results are verified by comparing the estimated and experimental rotor unbalance responses, which shows high accuracy.
Developing Dynamic Digital Image Techniques with Continuous Parameters to Detect Structural Damage
Directory of Open Access Journals (Sweden)
Ming-Hsiang Shih
2013-01-01
Full Text Available Several earthquakes with strong magnitude occurred globally at various locations, especially the unforgettable tsunami disaster caused by the earthquake in Indonesia and Japan. If the characteristics of structures can be well understood to implement new technology, the damages caused by most natural disasters can be significantly alleviated. In this research, dynamic digital image correlation method for using continuous parameter is applied for developing a low-cost digital image correlation coefficient method with advanced digital cameras and high-speed computers. The experimental study using cantilever test object with defect control confirms that the vibration mode calculated using this proposed method can highly express the defect locations. This proposed method combined with the sensitivity of Inter-Story Drift Mode Shape, IDMS, can also reveal the damage degree of damage structure. These test and analysis results indicate that this proposed method is high enough for applying to achieve the object of real-time online monitoring of structure.
Zhang, Guanglei; Pu, Huangsheng; He, Wei; Liu, Fei; Luo, Jianwen; Bai, Jing
2015-02-01
Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.
Lugo-Frías, Rodrigo; Klapp, Sabine H L
2016-06-22
This paper is concerned with the dynamics of a binary mixture of rod-like, repulsive colloidal particles driven out of equilibrium by means of a steady shear flow (Couette geometry). To this end we first derive, starting from a microscopic density functional in Parsons-Lee approximation, a mesoscopic free energy functional whose main variables are the orientational order parameter tensors. Based on this mesoscopic functional we then explore the stability of isotropic and nematic equilibrium phases in terms of composition and rod lengths. Second, by combining the equilibrium theory with the Doi-Hess approach for the order parameter dynamics under shear, we investigate the orientational dynamics of binary mixtures for a range of shear rates and coupling parameters. We find a variety of dynamical states, including synchronized oscillatory states of the two components, but also symmetry breaking behavior where the components display different in-plane oscillatory states.
Directory of Open Access Journals (Sweden)
Emer Bernal
2017-01-01
Full Text Available In this paper we are presenting a method using fuzzy logic for dynamic parameter adaptation in the imperialist competitive algorithm, which is usually known by its acronym ICA. The ICA algorithm was initially studied in its original form to find out how it works and what parameters have more effect upon its results. Based on this study, several designs of fuzzy systems for dynamic adjustment of the ICA parameters are proposed. The experiments were performed on the basis of solving complex optimization problems, particularly applied to benchmark mathematical functions. A comparison of the original imperialist competitive algorithm and our proposed fuzzy imperialist competitive algorithm was performed. In addition, the fuzzy ICA was compared with another metaheuristic using a statistical test to measure the advantage of the proposed fuzzy approach for dynamic parameter adaptation.
Energy Technology Data Exchange (ETDEWEB)
Remesat, D.
2008-07-01
Although hydrotreating has become a large part of refining operations for sour crudes, refiners rarely achieve their run lengths and crude throughput objectives for vacuum gas oil (VGO) hydrotreaters. This shortfall in performance can be attributed to crude flow changes, feed compositional changes, sulphur and metals changes, or hydrogen partial pressure changes, all of which reduce the effectiveness of the catalysts that remove sulphur from the crude oil streams. Although some proprietary steady state models exist to indicate performance enhancement during operation, they have not been widely used and it is not certain whether they would be effective in simulating the process with disturbances over the run length of the process. This study used publicly unattainable data gathered from 14 operating hydrotreaters and developed a lumped parameter dynamic model, using both Excel and HYSYS software, for industrial refinery/upgrader VGO hydrotreaters. The model takes proprietary and public steady state hydrotreater models and successfully applies it to a commercial dynamic simulation package. The model tracks changes in intrinsic reaction rate based on catalyst deactivation, wetting efficiency, feed properties and operating conditions to determine operating temperature, outlet sulphur composition and chemical hydrogen consumed. The model simulates local disturbances, and represents the start, middle and end operating zones during hydrotreater run length. This correlative, partially predictive model demonstrates the economic benefits of increasing hydrogen to improve the operation of a hydrotreater by increasing run length and/or improving crude processing.
Renormalized parameters and perturbation theory in dynamical mean-field theory for the Hubbard model
Hewson, A. C.
2016-11-01
We calculate the renormalized parameters for the quasiparticles and their interactions for the Hubbard model in the paramagnetic phase as deduced from the low-energy Fermi-liquid fixed point using the results of a numerical renormalization-group calculation (NRG) and dynamical mean-field theory (DMFT). Even in the low-density limit there is significant renormalization of the local quasiparticle interaction U ˜, in agreement with estimates based on the two-particle scattering theory of J. Kanamori [Prog. Theor. Phys. 30, 275 (1963), 10.1143/PTP.30.275]. On the approach to the Mott transition we find a finite ratio for U ˜/D ˜ , where 2 D ˜ is the renormalized bandwidth, which is independent of whether the transition is approached by increasing the on-site interaction U or on increasing the density to half filling. The leading ω2 term in the self-energy and the local dynamical spin and charge susceptibilities are calculated within the renormalized perturbation theory (RPT) and compared with the results calculated directly from the NRG-DMFT. We also suggest, more generally from the DMFT, how an approximate expression for the q ,ω spin susceptibility χ (q ,ω ) can be derived from repeated quasiparticle scattering with a local renormalized scattering vertex.
Mohamed, Omar Ahmed; Masood, Syed Hasan; Bhowmik, Jahar Lal; Nikzad, Mostafa; Azadmanjiri, Jalal
2016-07-01
In fused deposition modeling (FDM) additive manufacturing process, it is often difficult to determine the actual levels of process parameters in order to achieve the best dynamic mechanical properties of FDM manufactured part. This is mainly due to the large number of FDM parameters and a high degree of interaction between the parameters affecting such properties. This requires a large number of experiments to be determined. This paper presents a study on the influence of six FDM process parameters (layer thickness, air gap, raster angle, build orientation, road width, and number of contours) on the dynamic mechanical properties of the FDM manufactured parts using the fraction factorial design. The most influential parameters were statistically obtained through the analysis of variance (ANOVA) technique, and the results indicate that the layer thickness, the air gap, and the number of contours have the largest impact on dynamic mechanical properties. The optimal parameters for maximum dynamic mechanical properties were found to be layer thickness of 0.3302 mm, air gap of 0.00 mm, raster angle of 0.0°, build orientation of 0.0°, road width of 0.4572 mm, and 10 contours. Finally, a confirmation experiment was performed using optimized levels of process parameters, which showed good fit with the estimated values.
Three-stage Method for Identifying the Dynamic Model Parameters of Stranded Wire Helical Springs
Institute of Scientific and Technical Information of China (English)
ZHAO Yu; WANG Shilong; ZHOU Jie; LI Chuan; SUN Shouli
2015-01-01
The dynamic behavior of the stranded wire helical spring is described by a modified Bouc-Wen model while the model parameters must be identified using an identification method and experimental data. Existing identification methods usually relies either solely nonlinear iterative algorithms or manually trial and error. Therefore, the identification process can be rather time consuming and effort taking. As a result, these methods are not ideal for engineering applications. To come up with a more practical method, a three-stage identification method is proposed. Periodic loading and identification simulations are carried out to verify the effectiveness of the proposed method. Noises are added to the simulated data to test the performance of the proposed method when dealing with noise contaminated data. The simulation results indicate that the proposed method is able to give satisfying results when the noise levels are set to be 0.01, 0.03, 0.05 and 0.07. In addition, the proposed method is also applied to experimental data and compared with an existing method. The experimental data is acquired through a periodic loading test. The experiment results suggest that the proposed method features better accuracy compared with the existing method. An effective approach is proposed for identifying the model parameters of the stranded wire helical spring.
Some parameters in arctic sea ice dynamics from an expedition in the summer of 2003
Institute of Scientific and Technical Information of China (English)
LI Zhijun; ZHANG Zhanhai; LU Peng; DONG Xilu; CHENG Bin; CHEN Zhi
2005-01-01
On the basis of the investigated data for sea ice physical processes during the Second Chinese National Arctic Research Expedition (CHINARE-2003) in the summer of 2003, the sea ice dynamical characteristics were analyzed and the parameters describing these characteristics were given. The new findings discovered from these parameters are:(1) The ice concentration obtained from the investigation is two tenths to three tenths lower compared with that from the NOAA Ice Chart; and the ice thickness in the summer is 2 m less compared with the results obtained during the First Chinese National Arctic Research Expedition in 1999 (CHINARE-1999),(2) the standard deviation of the ice bottom fluctuation is 3.8 times that of the snow surface on the ice sheet; (3) the maximum speed of the ice floe on which camp CHIS7 is located (CHIS7 floe) is 1 300 m/h with rotation and oscillation. The rotation angle increased stepwise, the maximum being 37.8 ° , while the CHIS7 floe moved toward the north-east, and its rotation angle decreased stepwise.While the CHIS7 floe moved south-eastward. The oscillation period of CHIS7 floe is 12.45 h, which is consistent with that of the inertial current at the same latitude, showing the contribution of the inertial current to the ice floe movement.
Dynamic Mapping of Rice Growth Parameters Using HJ-1 CCD Time Series Data
Directory of Open Access Journals (Sweden)
Jing Wang
2016-11-01
Full Text Available The high temporal resolution (4-day charge-coupled device (CCD cameras onboard small environment and disaster monitoring and forecasting satellites (HJ-1A/B with 30 m spatial resolution and large swath (700 km have substantially increased the availability of regional clear sky optical remote sensing data. For the application of dynamic mapping of rice growth parameters, leaf area index (LAI and aboveground biomass (AGB were considered as plant growth indicators. The HJ-1 CCD-derived vegetation indices (VIs showed robust relationships with rice growth parameters. Cumulative VIs showed strong performance for the estimation of total dry AGB. The cross-validation coefficient of determination ( R C V 2 was increased by using two machine learning methods, i.e., a back propagation neural network (BPNN and a support vector machine (SVM compared with traditional regression equations of LAI retrieval. The LAI inversion accuracy was further improved by dividing the rice growth period into before and after heading stages. This study demonstrated that continuous rice growth monitoring over time and space at field level can be implemented effectively with HJ-1 CCD 10-day composite data using a combination of proper VIs and regression models.
Dynamical analysis of a cubic Liénard system with global parameters (II)
Chen, Hebai; Chen, Xingwu
2016-06-01
In this paper, we continue to study the global dynamics of a cubic Liénard system for global parameters in the case of three equilibria to follow (2015 Nonlinearity 28 3535-62), which deals with the case of two equilibria. We first analyse qualitative properties of all equilibria and judge the existences of limit cycles and homoclinic loops and their numbers. Then we obtain the bifurcation diagram and all phase portraits as our main results. Based on these results, in the case of three equilibria a positive answer to conjecture 3.2 of (1998 Nonlinearity 11 1505-19), which is about the existence of some function whose graph is exactly the surface of double limit cycles, is obtained. Moreover, a parameter region for the nonexistence of figure-eight loops is given theoretically to compensate for previous numerical results and is illustrated numerically. Supported by NSFC 11471228, 11572263, the Fundamental Research Funds for the Central Universities and Cultivation Foundation of Excellent Doctoral Dissertation of Southwest Jiaotong University (2015).
Effects of configuration parameters on lateral dynamics of tractor–two trailer combinations
Directory of Open Access Journals (Sweden)
Hongguo Xu
2015-12-01
Full Text Available The optimum configuration parameters of tractor–trailer combinations for lateral stability performance are proposed by adjusting the length of dolly and the second trailer’s center of gravity. A linear yaw plane model of vehicle combinations is adopted for dynamic analysis, and the model is calibrated by TruckSim. According to the yaw rate rearward amplification ratio of lateral response index, and combining the simulation results of MATLAB/Simulink, dolly and the second trailer are the dominate factors for lateral stability of vehicle combinations. Simulation results show that the distance between articulation joints of dolly is 1.6 m; simultaneously, the rate of distance between front hitch and center of gravity of the second trailer to its front and rear wheelbase is 0.41 and may gain the best lateral performance. Compared with configuration parameters of the original vehicle combinations, the results also illustrate that the one derived from adjustment approach reduces high-speed rearward amplification ratio by 11.4%. The proposed approach might be used for identifying desired design variables of the tractor–two trailer combinations and provided theoretical basis for stability tests.
Towards a Collision-Free WLAN: Dynamic Parameter Adjustment in CSMA/E2CA
Directory of Open Access Journals (Sweden)
Bellalta Boris
2011-01-01
Full Text Available Carrier sense multiple access with enhanced collision avoidance (CSMA/ECA is a distributed MAC protocol that allows collision-free access to the medium in WLANs. The only difference between CSMA/ECA and the well-known CSMA/CA is that the former uses a deterministic backoff after successful transmissions. Collision-free operation is reached after a transient state during which some collisions may occur. This paper shows that the duration of the transient state can be shortened by appropriately setting the contention parameters. Standard absorbing Markov chain theory is used to describe the behaviour of the system in the transient state and to predict the expected number of slots to reach the collision-free operation. The paper also introduces CSMA/E2CA, in which a deterministic backoff is used two consecutive times after a successful transmission. CSMA/E2CA converges quicker to collision-free operation and delivers higher performance than CSMA/ECA, specially in harsh wireless scenarios with high frame-error rates. The last part of the paper addresses scenarios with a large number of contenders. We suggest dynamic parameter adjustment techniques to accommodate a varying (and potentially high number of contenders. The effectiveness of these adjustments in preventing collisions is validated by means of simulation.
Description of patellar movement by 3D parameters obtained from dynamic CT acquisition
de Sá Rebelo, Marina; Moreno, Ramon Alfredo; Gobbi, Riccardo Gomes; Camanho, Gilberto Luis; de Ávila, Luiz Francisco Rodrigues; Demange, Marco Kawamura; Pecora, Jose Ricardo; Gutierrez, Marco Antonio
2014-03-01
The patellofemoral joint is critical in the biomechanics of the knee. The patellofemoral instability is one condition that generates pain, functional impairment and often requires surgery as part of orthopedic treatment. The analysis of the patellofemoral dynamics has been performed by several medical image modalities. The clinical parameters assessed are mainly based on 2D measurements, such as the patellar tilt angle and the lateral shift among others. Besides, the acquisition protocols are mostly performed with the leg laid static at fixed angles. The use of helical multi slice CT scanner can allow the capture and display of the joint's movement performed actively by the patient. However, the orthopedic applications of this scanner have not yet been standardized or widespread. In this work we present a method to evaluate the biomechanics of the patellofemoral joint during active contraction using multi slice CT images. This approach can greatly improve the analysis of patellar instability by displaying the physiology during muscle contraction. The movement was evaluated by computing its 3D displacements and rotations from different knee angles. The first processing step registered the images in both angles based on the femuŕs position. The transformation matrix of the patella from the images was then calculated, which provided the rotations and translations performed by the patella from its position in the first image to its position in the second image. Analysis of these parameters for all frames provided real 3D information about the patellar displacement.
HFOLD - A program package for calculating two-body MSSM Higgs decays at full one-loop level.
Frisch, W; Eberl, H; Hluchá, H
2011-10-01
HFOLD (Higgs Full One Loop Decays) is a Fortran program package for calculating all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The package is done in the SUSY Parameter Analysis convention and supports the SUSY Les Houches Accord input and output format. PROGRAM SUMMARY: Program title: HFOLD Catalogue identifier: AEJG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 340 621 No. of bytes in distributed program, including test data, etc.: 1 760 051 Distribution format: tar.gz Programming language: Fortran 77 Computer: Workstation, PC Operating system: Linux RAM: 524 288 000 Bytes Classification: 11.1 External routines: LoopTools 2.2 (http://www.feynarts.de/looptools/), SLHALib 2.2 (http://www.feynarts.de/slha/). The LoopTools code is included in the distribution package. Nature of problem: A future high-energy e+e- linear collider will be the best environment for the precise measurements of masses, cross sections, branching ratios, etc. Experimental accuracies are expected at the per-cent down to the per-mile level. These must be matched from the theoretical side. Therefore higher order calculations are mandatory. Solution method: This program package calculates all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The renormalization is done in the DR scheme following the SUSY Parameter Analysis convention. The program supports the SUSY Les Houches Accord input and output format. Running time: The example provided takes only a few seconds to run.
Application of particle swarm optimization to parameter search in dynamical systems
Matsushita, Haruna; Saito, Toshimichi
This paper proposes an application of the particle swarm optimization (PSO) to analysis of switched dynamical systems (SDS). This is the first application of PSO to bifurcation analysis. We consider the application to an example of the SDS which relates to a simplified model of photovoltaic systems such that the input is a single solar cell and is converted to the output via a boost converter. Our SDS includes a piecewise linear current-controlled voltage source that is a simplified model of the solar cell and the switching rule is a variant of peak-current-controlled switching. We derive two equations that give period-doubling bifurcation set and the maximum power point (MPP) for the parameter: they are objective of the analysis. The two equations are transformed into an multi objective problem (MOP) described by the hybrid fitness function consisting of two functions evaluating the validity of parameters and criteria. The proposed method permits increase (deteriorate) of some component below the criterion and the increase can help to exclude the bad component. This criteria effect helps an improvement of trade-off problems in existing MOP solvers. Furthermore, by using the piecewise exact solution and return map for the simulation, the MOP is described exactly and the PSO can find the precise (approximate) solution. From simulation results, we confirm that the PSO for the MOP can easily find the solution parameters although a standard numerical calculation needs huge calculation amount. The efficiency of the proposed algorithm is confirmed by measuring in terms of accuracy, computation amount and robustness.
Energy Technology Data Exchange (ETDEWEB)
Meliopoulos, Sakis [Georgia Inst. of Technology, Atlanta, GA (United States); Cokkinides, George [Georgia Inst. of Technology, Atlanta, GA (United States); Fardanesh, Bruce [New York Power Authority, NY (United States); Hedrington, Clinton [U.S. Virgin Islands Water and Power Authority (WAPA), St. Croix (U.S. Virgin Islands)
2013-12-31
This is the final report for this project that was performed in the period: October1, 2009 to June 30, 2013. In this project, a fully distributed high-fidelity dynamic state estimator (DSE) that continuously tracks the real time dynamic model of a wide area system with update rates better than 60 times per second is achieved. The proposed technology is based on GPS-synchronized measurements but also utilizes data from all available Intelligent Electronic Devices in the system (numerical relays, digital fault recorders, digital meters, etc.). The distributed state estimator provides the real time model of the system not only the voltage phasors. The proposed system provides the infrastructure for a variety of applications and two very important applications (a) a high fidelity generating unit parameters estimation and (b) an energy function based transient stability monitoring of a wide area electric power system with predictive capability. Also the dynamic distributed state estimation results are stored (the storage scheme includes data and coincidental model) enabling an automatic reconstruction and “play back” of a system wide disturbance. This approach enables complete play back capability with fidelity equal to that of real time with the advantage of “playing back” at a user selected speed. The proposed technologies were developed and tested in the lab during the first 18 months of the project and then demonstrated on two actual systems, the USVI Water and Power Administration system and the New York Power Authority’s Blenheim-Gilboa pumped hydro plant in the last 18 months of the project. The four main thrusts of this project, mentioned above, are extremely important to the industry. The DSE with the achieved update rates (more than 60 times per second) provides a superior solution to the “grid visibility” question. The generator parameter identification method fills an important and practical need of the industry. The “energy function” based
Two-body physics in the Su-Schrieffer-Heeger model
Di Liberto, M.; Recati, A.; Carusotto, I.; Menotti, C.
2016-12-01
We consider two interacting bosons in a dimerized Su-Schrieffer-Heeger (SSH) lattice. We identify a rich variety of two-body states. In particular, for open boundary conditions and moderate interactions, edge bound states (EBS) are present even for the dimerization that does not sustain single-particle edge states. Moreover, for large values of the interactions, we find a breaking of the standard bulk-boundary correspondence. Based on the mapping of two interacting particles in one dimension onto a single particle in two dimensions, we propose an experimentally realistic coupled optical fibers setup as quantum simulator of the two-body SSH model. This setup is able to highlight the localization properties of the states as well as the presence of a resonant scattering mechanism provided by a bound state that crosses the scattering continuum, revealing the closed-channel population in real time and real space.
Distribution of level spacing ratios using one- plus two-body random matrix ensembles
Indian Academy of Sciences (India)
N D Chavda
2015-02-01
Probability distribution (()) of the level spacing ratios has been introduced recently and is used to investigate many-body localization as well as to quantify the distance from integrability on finite size lattices. In this paper, we study the distribution of the ratio of consecutive level spacings using one-body plus two-body random matrix ensembles for finite interacting many-fermion and many-boson systems. () for these ensembles move steadily from the Poisson to the Gaussian orthogonal ensemble (GOE) form as the two-body interaction strength is varied. Other related quantities are also used in the analysis to obtain critical strength c for the transition. The c values deduced using the () analysis are in good agreement with the results obtained using the nearest neighbour spacing distribution (NNSD) analysis.
The two-body problem of a pseudo-rigid body and a rigid sphere
DEFF Research Database (Denmark)
Kristiansen, Kristian Uldall; Vereshchagin, M.; Gózdziewski, K.;
2012-01-01
n this paper we consider the two-body problem of a spherical pseudo-rigid body and a rigid sphere. Due to the rotational and "re-labelling" symmetries, the system is shown to possess conservation of angular momentum and circulation. We follow a reduction procedure similar to that undertaken...... in the study of the two-body problem of a rigid body and a sphere so that the computed reduced non-canonical Hamiltonian takes a similar form. We then consider relative equilibria and show that the notions of locally central and planar equilibria coincide. Finally, we show that Riemann's theorem on pseudo......-rigid bodies has an extension to this system for planar relative equilibria....
CP Violating Polarization Asymmetry in Charmless Two-Body Decays of Beauty Baryons
He, Min; Li, Guan-Nan
2015-01-01
Several baryons containing a heavy b-quark, the b-baryons, have been discovered. The charmless two-body decays of b-baryons can provide a new platform for CP violating studies in a similar way as charmless two-body decays of B-meson. In b-baryon decays there are new CP violating observable related to baryon polarization. We show that in the flavor $SU(3)$ limit there exist relations involve different combinations of the decay amplitudes compared with those in CP violating rate asymmetry. These new relations therefore provide interesting tests for the mechanism of CP in the standard model (SM) and flavor $SU(3)$ symmetry. Future data from LHCb can test these relations.
Energy Centroids of Spin $I$ States by Random Two-body Interactions
Zhao, Y M; Ogawa, K
2005-01-01
In this paper we study the behavior of energy centroids (denoted as $\\bar{E_I}$) of spin $I$ states in the presence of random two-body interactions, for systems ranging from very simple systems (e.g. single-$j$ shell for very small $j$) to very complicated systems (e.g., many-$j$ shells with different parities and with isospin degree of freedom). Regularities of $\\bar{E_I}$'s discussed in terms of the so-called geometric chaoticity (or quasi-randomness of two-body coefficients of fractional parentage) in earlier works are found to hold even for very simple systems in which one cannot assume the geometric chaoticity. It is shown that the inclusion of isospin and parity does not "break" the regularities of $\\bar{E_I}$'s.
A Tale of Three Equations Breit, Eddington-Guant, and Two-Body Dirac
Van Alstine, P; Alstine, Peter Van; Crater, Horace W.
1997-01-01
G.Breit's original paper of 1929 postulates the Breit equation as a correction to an earlier defective equation due to Eddington and Gaunt, containing a form of interaction suggested by Heisenberg and Pauli. We observe that manifestly covariant electromagnetic Two-Body Dirac equations previously obtained by us in the framework of Relativistic Constraint Mechanics reproduce the spectral results of the Breit equation but through an interaction structure that contains that of Eddington and Gaunt. By repeating for our equation the analysis that Breit used to demonstrate the superiority of his equation to that of Eddington and Gaunt, we show that the historically unfamiliar interaction structures of Two-Body Dirac equations (in Breit-like form) are just what is needed to correct the covariant Eddington Gaunt equation without resorting to Breit's version of retardation.
SU-E-T-597: Influence of Smoothing Parameters on Dynamic IMRT Plan Quality and Deliverability.
Manigandan, D; Sharma, S; Gandhi, A; Subramani, V; Sharma, D; Kumar, P; Julka, P; Rath, G
2012-06-01
To study the impact of different smoothing parameters on IMRT plan quality and deliverabilityMethods: Five previously treated patients of carcinoma cervix were chosen. Planning target volume (PTV) and organ at risk (OAR) i.e. bladder and rectum were contoured. In each case, five different dynamic IMRT plans with 6MV photon beam were created in eclipse TPS for Varian 2300C/D linear accelerator. During optimization, dose volume constraints and priorities were kept constant and smoothing parameters were varied as follows: 10/5, 40/30 (TPS default value), 80/60, 100/80 and 200/150 in x/y direction. Total dose was 5040cGy in 28 fractions and prescribed at 95% isodose. Plan quality was analyzed by means of coverage index (CI=PTV covered by prescription dose/PTV), OAR mean doses and total monitor units (MUs) required to deliver a plan. In each case, deliverability of treatment plans were verified with I'matriXX ion-chamber array and compared with TPS dose-plane using gamma index of 3% dose difference and 3mm distance to agreement criteria. The CI values were 0.9435±0.032, 0.9418±0.034, 0.9380±0.041, 0.9330±0.047 and 0.8681±0.072 for 10/5, 40/30, 80/60, 100/80 and 200/150 in x/y direction. PTV dose maximum decreases with the increase of smoothing parameters and values were 5724.38±106.08 5723.30±131.60, 5708.44±1 16.74, 5697.92±116.82 and 5587.50±189.50cGy. The bladder mean doses were 4027.46±630.40, 3821.62±420.62, 3819.58±427.08, 3813.42±435.02 and 3814.78±438.0cGy. Rectum mean doses were 3839.88±466.02, 3835.52±473.18, 3837.52±472.88, 3839.10±471.20 and 3918.94±469.76cGy. Similarly, Total MUs were 1588±205, 1573±214, 1513±274, 1456±335 and 1219±68. Gamma pass rate increases with the increase of smoothing parameters and values were 99.16±0.21%, 99.07±0.19%, 99.24±0.28%, 99.29±0.29% and 99.75±0.15%. When smoothing parameters decreased below TPS default value, plan quality increases, but deliverability decreases. If smoothing parameters
Large-j Expansion Method for Two-Body Dirac Equation
Directory of Open Access Journals (Sweden)
Askold Duviryak
2006-02-01
Full Text Available By using symmetry properties, the two-body Dirac equation in coordinate representation is reduced to the coupled pair of radial second-order differential equations. Then the large-j expansion technique is used to solve a bound state problem. Linear-plus-Coulomb potentials of different spin structure are examined in order to describe the asymptotic degeneracy and fine splitting of light meson spectra.
Two bodies gravitational system with variable mass and damping-antidamping effect due to star wind
López, G V
2009-01-01
We study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-antidamping effect due to star wind during its motion. A constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion of the system, and the period of the body is studied using the constant of motion of the system. An application to the comet motion is given, using the comet Halley as an example.
Kinematics of τ two-body decay near τ threshold at BESⅢ
Institute of Scientific and Technical Information of China (English)
莫晓虎
2010-01-01
The kinematic properties of two-body decay near τ threshold are studied according to the special capacity of the BEPC accelerator and the BESⅢ detector.Explicitly presented are the transformations of energy and momentum of hadronic particles between different reference frames,and the corresponding distributions.A brand new method is proposed to obtain the energy spread of the accelerator by fitting the energy distribution of hadron from τ semi-leptonic decays.
New fixed points of the renormalisation group for two-body scattering
Energy Technology Data Exchange (ETDEWEB)
Birse, M.C. [The University of Manchester, Theoretical Physics Division, School of Physics and Astronomy, Manchester (United Kingdom); Epelbaum, E. [Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik II, Fakultaet fuer Physik und Astronomie, Bochum (Germany); Gegelia, J. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich (Germany); Tbilisi State University, Tbilisi (Georgia)
2016-02-15
We outline a separable matrix ansatz for the potentials in effective field theories of non-relativistic two-body systems with short-range interactions. We use this ansatz to construct new fixed points of the renormalisation-group equation for these potentials. New fixed points indicate a much richer structure than previously recognized in the RG flows of simple short-range potentials. (orig.)
Regularities of many-body systems interacting by a two-body random ensemble
Energy Technology Data Exchange (ETDEWEB)
Zhao, Y.M. [Department of Physics, Shanghai Jiao-Tong University, Shanghai 200030 (China) and Cyclotron Center, Institute of Physical and Chemical Research - RIKEN, Hirosawa 2-1, Wako-shi, Saitama 351-0198 (Japan) and Department of Physics, Southeast University, Nanjing 210018 (China)]. E-mail: ymzhao@riken.jp; Arima, A. [Science Museum, Japan Science Foundation, 2-1 Kitanomaru-Koen, Chiyodaku, Tokyo 102-0091 (Japan); Yoshinaga, N. [Department of Physics, Saitama University, Saitama 338-0625 (Japan)
2004-10-01
The ground states of all even-even nuclei have angular momentum, I, equal to zero, I=0, and positive parity, {pi}=+. This feature was believed to be a consequence of the attractive short-range interaction between nucleons. However, in the presence of two-body random interactions, the predominance of I{pi}=0+ ground states (0 g.s.) was found to be robust both for bosons and for an even number of fermions. For simple systems, such as d bosons, sp bosons, sd bosons, and a few fermions in single-j shells for small j, there are a few approaches to predict and/or explain spin I ground state (I g.s.) probabilities. An empirical approach to predict I g.s. probabilities is available for general cases, such as fermions in a single-j (j>72) or many-j shells and various boson systems, but a more fundamental understanding of the robustness of 0 g.s. dominance is still out of reach. Further interesting results are also reviewed concerning other robust phenomena of many-body systems in the presence of random two-body interactions, such as the odd-even staggering of binding energies, generic collectivity, the behavior of average energies, correlations, and regularities of many-body systems interacting by a displaced two-body random ensemble.
Adamuszek, Marta; Dabrowski, Marcin; Schmalholz, Stefan M.; Urai, Janos L.; Raith, Alexander
2015-04-01
Salt structures have been identified as a potential target for hydrocarbon, CO2, or radioactive waste storage. The most suitable locations for magazines are considered in the thick and relatively homogeneous rock salt layers. However, salt structures often consist of the evaporite sequence including rock salt intercalated with other rock types e.g.: anhydrite, gypsum, potassium and magnesium salt, calcite, dolomite, or shale. The presence of such heterogeneities causes a serious disturbance in the structure management. Detailed analysis of the internal architecture and internal dynamics of the salt structure are crucial for evaluating them as suitable repositories and also their long-term stability. The goal of this study is to analyse the influence of the presence of anhydrite layers on the internal dynamics of salt structures. Anhydrite is a common rock in evaporite sequences. Its physical and mechanical properties strongly differ from the properties of rock salt. The density of anhydrite is much higher than the density of salt, thus anhydrite is likely to sink in salt causing the disturbance of the surrounding structures. This suggestion was the starting point to the discussion about the long-term stability of the magazines in salt structures [1]. However, the other important parameter that has to be taken into account is the viscosity of anhydrite. The high viscosity ratio between salt and anhydrite can restrain the layer from sinking. The rheological behaviour of anhydrite has been studied in laboratory experiments [2], but the results only provide information about the short-term behaviour. The long-term behaviour can be best predicted using indirect methods e.g. based on the analysis of natural structures that developed over geological time scale. One of the most promising are fold structures, the shape of which is very sensitive to the rheological parameters of the deforming materials. Folds can develop in mechanically stratified materials during layer
Network Parameters Impact on Dynamic Transmission Power Control in Vehicular Ad hoc Networks
Directory of Open Access Journals (Sweden)
Khan Muhammad Imran
2013-09-01
Full Text Available In vehicular ad hoc networks, the dynamic change in transmission power is very effective to increase the throughput of the wireless vehicular network and decrease the delay of the message communicationbetween vehicular nodes on the highway. Whenever an event occurs on the highway, the reliability of the communication in the vehicular network becomes so vital so that event created messages shouldreach to all the moving network nodes. It becomes necessary that there should be no interference fromoutside of the network and all the neighbor nodes should lie in the transmission range of thereference vehicular node. Transmission range is directly proportional to the transmission power the moving node. If the transmission power will be high, the interference increases that can cause higherdelay in message reception at receiver end, hence the performance of the network decreased. In this paper, it is analyzed that how transmission power can be controlled by considering other differentparameter of the network such as; density, distance between moving nodes, different types of messages dissemination with their priority, selection of an antenna also affects on the transmission power. Thedynamic control of transmission power in VANET serves also for the optimization of the resources where it needs, can be decreased and increased depending on the circumstances of the network.Different applications and events of different types also cause changes in transmission power to enhance the reachability. The analysis in this paper is comprised of density, distance with single hop and multihop message broadcasting based dynamic transmission power control as well as antenna selection and applications based. Some summarized tables are produced according to the respective parameters of the vehicular network. At the end some valuable observations are made and discussed in detail. This paper concludes with a grand summary of all the protocols discussed in it.
Blanco, A E; Icken, W; Ould-Ali, D; Cavero, D; Schmutz, M
2014-10-01
Egg quality traits are of utmost importance in layer breeding programs due to their effect on profitability in the egg production industry and on the production of quality chicks. Therefore, the aim of this study was to analyze and estimate genetic parameters of different quality traits: egg weight, breaking strength, dynamic stiffness (Kdyn), egg shape index, eggshell thickness, and albumen height. Eggs were obtained from 4 pure lines of birds. Two different tests were performed: a white breeding program, with eggs from a male and female line of a white egg layer program that were analyzed at 67 to 70 wk of age, and a brown breeding program, with eggs from a male and female line of a brown egg layer program that were analyzed at 32 to 36 wk of age. In general, heritabilities were moderate to high for all traits (h² = 0.23 to 0.71). A high genetic correlation was estimated in both tests between breaking strength and Kdyn (rg = +0.40 to +0.61). Shell thickness was also positively correlated with breaking strength (rg = +0.50 to +0.63) and Kdyn (rg = +0.28 to +0.69). These moderate relationships demonstrate that the strength of an egg not only relies on the shell thickness but also on the quality and uniformity of eggshell construction. Dynamic stiffness might be preferred for breeding purposes due to its lower negative genetic correlation with egg weight and its higher heritability (h² = 0.35 to 0.70) compared with breaking strength (h² = 0.23 to 0.35). Breaking strength and Kdyn were positively correlated with shape index, which confirms that round eggs will show higher shell stability. Therefore, it is necessary to monitor egg shape to maintain an optimal form.
Gilmanov, T. G.; Wylie, B. K.; Howard, D. M.
2012-12-01
Net CO2 exchange data from long-term flux tower measurements in monocotyledonous (wheat, maize) and dicotyledonous (soybeans, alfalfa, peas, peanuts) crops were partitioned into photosynthesis (P) and respiration (R) using the light-soil temperature-VPD response method. Analysis of the resulting time series of P and R revealed patterns of temporal and phenological dynamics in these plant groups. We established differences in ranges and dynamic patterns of P and R as well as CO2 exchange parameters (quantum yield, photosynthetic capacity, respiration rate, light-use efficiency, curvature of the VPD response). Weekly P and R data combined with remotely sensed 7-day eMODIS NDVI allow identification of the quasi-linear relationships between P, R, and NDVI, as well as estimation of parameters of NDVI response (start of the growing season, duration of the linearity period, slope of NDVI response). While the linear-like patterns occur early in the season, later the flux response to NDVI becomes less pronounced, and for the whole season the flux-NDVI relationship assumes a hysteresis-like pattern. Introduction of VPD and soil moisture limitation as well as phenological controls (growing degree days) leads to more flexible models for P and R in relation to NDVI and on-site drivers. These models allow mapping of the cropland CO2 exchange at regional and larger scales (e.g., the Great Plains). Significant relationships of the crop GPP to the seasonally integrated NDVI were also established, providing an opportunity for mapping of crop productivity using geographically distributed historic NDVI data. On the other hand, long time series (6 to 12 years and longer) of weekly P and R data lead to models of annual photosynthesis and respiration in response to climatic factors that may be used for prognostic purposes. We developed a model of maize GPP on the Great Plains in relation to the sum of temperatures above 5 °C and the hydrologic year precipitation. The model describes 75
Determining dynamic parameters of different-scale ionospheric irregularities over northern Siberia
Afraimovich, E. L.; Lipko, Y. V. Y. V.; Vugmeister, B. O.
2000-01-01
In 1995-1996, observations were carried out at Norilsk (geomagnetic latitude and longitude 64.2 degN and 160.4 degE) to determine dynamic parameters of irregularities in the high-latitude ionosphere. The short-baseline spaced-receiver method that has been implemented at the ionospheric facility of the Norilsk Integrated Magnetic-Ionospheric Station, provides a means of simultaneously measuring parameters of small-scale irregularities (spatial scale of 3-5 km) by the Similar-Fading Method (SFM), as well as of medium-scale irregularities (time scale of 10-30 min, spatial scale of hundreds of kilometres) by the Statistical Angle-of-arrival and Doppler Method (SADM). About 20 h of the observational data for the F2-layer under quiet geomagnetic conditions (Kp = 3) and about 15 h for the sporadic E-layer (Kp ~ 3) were processed. It has been found that the propagation directions and velocities of different-scale irregularities do not coincide. Small-scale irregularities of the F2-layer travel predominantly eastward or westward. The velocity of the F2-layer irregularities is about 100 m/s, and under disturbed conditions it is up to 200-250 m/s. Small-scale irregularities of the sporadic E-layer travel mostly in the northward direction. It is confirmed that the Es-layer is characterised by high velocities of the irregularities (as high as 1000 m/s). Medium-scale irregularities with periods in the range of 10-30 min travel mostly in a southward direction with velocities of 20-40 m/s.
Population dynamic parameters of the red mullet Mullus barbatus (Mullidae in the Arzew Gulf, Algeria
Directory of Open Access Journals (Sweden)
Lotfi Bensahla Talet
2016-02-01
Full Text Available Population dynamic parameters of red mullet, Mullus barbatus (n=592 caught by trawlers operating in Arzew Gulf (Algeria in the western Mediterranean were studied. Samples were collected between February 2013 and January 2014. Females ranged from 10.9-23.2 cm in total length and 12-149.2 g in weight whereas males length was comprised between 12.6 and 19.7 cm and weight between 21.3 and 99.9 g. The relationship between length and weight was W=0.00167L2.842 (r²=0.850. Growth parameters of the von Bertalanffy equation were: L∞=20.89 cm, K=0.66 year-1, t0=-0.143 year for males, while for females: L∞=250.9 cm, K=0.6 year-1, t0=-0.015 year. Estimates of total (Z, natural (M and fishing (F mortalities were: 1.58, 0.8 and 0.79, respectively and the estimated exploitation ratio 0.5 indicating that the resource is being exploited at its limit in this area. The virtual population analysis of M. barbatus by VIT software showed that the number of recruits per year was estimated at 4447304.6 individuals, balanced total biomass was estimated at 168 486 tons, the gains are represented by recruitment 51.71 tons (30.69% and growth 116.76 tons (69.31%, losses are represented by natural mortality 98.48 tons (58.45% and fishing mortality 70 tons (41.55%. The current yield per recruit was estimated to Y/R=15.74 g and maximum sustainable yield can be reached by increasing the current fishing effort to stabilize it at MSY=17.91 g.
Energy Technology Data Exchange (ETDEWEB)
Chakiba, Camille [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Cornelis, François [Department of Radiology, Pellegrin Hospital, Bordeaux (France); Descat, Edouard [Department of Radiology, Saint-Augustin Clinic, Bordeaux (France); Gross-Goupil, Marine [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Sargos, Paul [Department of Radiotherapy, Bergonié Cancer Institute, Bordeaux (France); Roubaud, Guilhem [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Houédé, Nadine, E-mail: nadine.houede@chu-nimes.fr [Department of Medical Oncology, Bergonié Cancer Institute, Bordeaux (France); Department of Medical Oncology, Nimes University Hosptital, Nîmes (France)
2015-06-15
Highlights: • DCE-MRI parameters could be useful biomarker for patients with localized bladder carcinoma. • Rate of relapse is lower for good responders assessed by DCE-MRI. • The use of DCE-MRI parameters may improve the standardization of patients’ selection before surgery. - Abstract: Objectives: To evaluate the performance of dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging to assess the histological response after chemotherapy on bladder carcinoma. Methods: From 2008 to 2010, 12 patients presenting localized urothelial carcinoma of the bladder were prospectively evaluated by DCE-MR imaging before and after two courses of cisplatin-based neoadjuvant chemotherapy. Size and thickness of tumours were measured. Relative enhancement at the arterial (rSI{sub 35s}) and venous phases (rSI{sub 80s}) of each tumour was obtained. Histological response was assessed and outcomes were recorded. Results: Histological examination after neoadjuvant chemotherapy concluded as pathological complete response (pCR) for 6 out of 12 patients. Five patients developed recurrences (4/6 no pCR and 1/6 pCR). Significant differences, between before and after treatment, were found for patients with complete pathological response after chemotherapy for all MR quantitative values. Tumours decreased in size and thickness (both P = 0.03). After treatment, rSI{sub 80s} was significantly different between pCR and non-pCR patients (P = 0.04) with a cut-off value of 40%. For this cut-off, sensitivity, specificity and accuracy were 83.33%. Similar recurrence free survivals were obtained if applying the MR cut-off value or the histopathological findings. Conclusion: Our results suggest that DCE-MR imaging may be a useful biomarker for patients with localized bladder carcinoma, improving selection before surgery.
Yan, Yangqian; Blume, D.
2015-09-01
The low-energy spectrum of N -boson clusters with pairwise zero-range interactions is believed to be governed by a three-body parameter. We study the ground state of N -boson clusters with infinite two-body s -wave scattering length by performing ab initio Monte Carlo simulations. To prevent Thomas collapse, different finite-range three-body regulators are used. The energy and structural properties for the three-body Hamiltonian with two-body zero-range interactions and three-body regulator are in much better agreement with the "ideal zero-range Efimov theory" results than those for Hamiltonian with two-body finite-range interactions. For larger clusters we find that the ground-state energy and structural properties of the Hamiltonian with two-body zero-range interactions and finite-range three-body regulators are not universally determined by the three-body parameter, i.e., dependencies on the specific form of the three-body regulator are observed. For comparison, we consider Hamiltonian with two-body van der Waals interactions and no three-body regulator. For the interactions considered, the ground-state energy of the N -body clusters is—if scaled by the three-body ground-state energy—fairly universal, i.e., the dependence on the short-range details of the two-body van der Waals potentials is small. Our results are compared with those in the literature.
Benevicius, Vincas; Ostasevicius, Vytautas; Gaidys, Rimvydas
2013-08-22
Due to their small size, low weight, low cost and low energy consumption, MEMS accelerometers have achieved great commercial success in recent decades. The aim of this research work is to identify a MEMS accelerometer structure for human body dynamics measurements. Photogrammetry was used in order to measure possible maximum accelerations of human body parts and the bandwidth of the digital acceleration signal. As the primary structure the capacitive accelerometer configuration is chosen in such a way that sensing part measures on all three axes as it is 3D accelerometer and sensitivity on each axis is equal. Hill climbing optimization was used to find the structure parameters. Proof-mass displacements were simulated for all the acceleration range that was given by the optimization problem constraints. The final model was constructed in Comsol Multiphysics. Eigenfrequencies were calculated and model's response was found, when vibration stand displacement data was fed into the model as the base excitation law. Model output comparison with experimental data was conducted for all excitation frequencies used during the experiments.
Energy Technology Data Exchange (ETDEWEB)
Jabehdar Maralani, Pejman [University of Toronto, Department of Medical Imaging, Sunnybrook Health Sciences Center, Toronto, ON (Canada); Melhem, Elias R.; Herskovits, Edward H. [University of Maryland Medical Center, Department of Radiology, Baltimore, MD (United States); Wang, Sumei; Voluck, Matthew R.; Learned, Kim O.; Mohan, Suyash [Perelman School of Medicine at University of Pennsylvania, Department of Radiology, Division of Neuroradiology, Philadelphia, PA (United States); Kim, Sang Joon [University of Ulsan Asan Medical Center, Department of Radiology, Songpa-gu, Seoul (Korea, Republic of); O' Rourke, Donald M. [Perelman School of Medicine at University of Pennsylvania, Department of Surgery, Division of Neurosurgery, Philadelphia, PA (United States)
2015-09-15
We aimed to evaluate the prognostic value of dynamic susceptibility contrast (DSC) MR perfusion in elderly patients with glioblastomas (GBM). Thirty five patients aged ≥65 and 35 aged <65 years old, (referred to as elderly and younger, respectively) were included in this retrospective study. The median relative cerebral volume (rCBV) from the enhancing region (rCBV{sub ER-Med}) and immediate peritumoral region (rCBV{sub IPR-Med}) and maximum rCBV from the enhancing region of the tumor (rCBV{sub ER-Max}) were compared and correlated with survival data. Analysis was repeated after rCBVs were dichotomized into high and low values and after excluding elderly patients who did not receive postoperative chemoradiation (34.3 %). Kaplan-Meyer survival curves and parametric and semi-parametric regression tests were used for analysis. All rCBV parameters were higher in elderly compared to younger patients (p < 0.05). After adjustment for age, none were independently associated with shorter survival (p > 0.05). After rCBV dichotomization into high and low values, high rCBV in elderly was independently associated with shorter survival compared to low rCBV in elderly, or any rCBV in younger patients (p < 0.05). rCBV can be an imaging biomarker to identify a subgroup of GBM patients in the elderly with worse prognosis compared to others. (orig.)
The Influence of Meteorological Parameters and Other Factors on Soil Radon Dynamics
Yakovleva, V. S.; Nagorsky, P. M.; Kondratyeva, A. G.; Mishina, N. V.
2016-08-01
The paper presents the results of the research in the degree of the effect of space weather meteorological parameters and factors on the dynamics of soil radon levels and α- and β-radiation flux densities in a seismically passive region. The cross-correlation analysis showed a significant correlation of β-radiation flux density with temperature in summer, and no correlation in winter. A significant relation between α- and β-radiation flux densities and pressure within the intra-annual range was not observed. The investigation of the high-intensity precipitation effect on radon volumetric activity and α- and β-radiation flux densities showed their abnormal increase. The dependence of the anomaly duration on the depth was revealed. The abnormal jumps in α- and β-radiation flux densities data series occur in the snow-melting periods as well. Low-intensity precipitations significantly violate the standard "diurnal variations" of α- and β-radiation soil fluxes and radon volumetric activity. Fourier analysis showed the diurnal (24 hours) and semidiurnal (12 hours) harmonics for the observed radiation values at a depth of 0.5 m. The obtained results can be used for interpretation of the data on the soil radon monitoring in order to predict earthquakes, etc.
Directory of Open Access Journals (Sweden)
Vincas Benevicius
2013-08-01
Full Text Available Due to their small size, low weight, low cost and low energy consumption, MEMS accelerometers have achieved great commercial success in recent decades. The aim of this research work is to identify a MEMS accelerometer structure for human body dynamics measurements. Photogrammetry was used in order to measure possible maximum accelerations of human body parts and the bandwidth of the digital acceleration signal. As the primary structure the capacitive accelerometer configuration is chosen in such a way that sensing part measures on all three axes as it is 3D accelerometer and sensitivity on each axis is equal. Hill climbing optimization was used to find the structure parameters. Proof-mass displacements were simulated for all the acceleration range that was given by the optimization problem constraints. The final model was constructed in Comsol Multiphysics. Eigenfrequencies were calculated and model’s response was found, when vibration stand displacement data was fed into the model as the base excitation law. Model output comparison with experimental data was conducted for all excitation frequencies used during the experiments.
Parameters Optimization for a Kind of Dynamic Vibration Absorber with Negative Stiffness
Directory of Open Access Journals (Sweden)
Yongjun Shen
2016-01-01
Full Text Available A new type of dynamic vibration absorber (DVA with negative stiffness is studied in detail. At first, the analytical solution of the system is obtained based on the established differential motion equation. Three fixed points are found in the amplitude-frequency curves of the primary system. The design formulae for the optimum tuning ratio and optimum stiffness ratio of DVA are obtained by adjusting the three fixed points to the same height according to the fixed-point theory. Then, the optimum damping ratio is formulated by minimizing the maximum value of the amplitude-frequency curves according to H∞ optimization principle. According to the characteristics of negative stiffness element, the optimum negative stiffness ratio is also established and it could still keep the system stable. In the end, the comparison between the analytical and the numerical solutions verifies the correctness of the analytical solution. The comparisons with three other traditional DVAs under the harmonic and random excitations show that the presented DVA performs better in vibration absorption. This result could provide theoretical basis for optimum parameters design of similar DVAs.
Shen, Chengcheng; Shi, Honghua; Liu, Yongzhi; Li, Fen; Ding, Dewen
2016-07-01
Marine ecosystem dynamic models (MEDMs) are important tools for the simulation and prediction of marine ecosystems. This article summarizes the methods and strategies used for the improvement and assessment of MEDM skill, and it attempts to establish a technical framework to inspire further ideas concerning MEDM skill improvement. The skill of MEDMs can be improved by parameter optimization (PO), which is an important step in model calibration. An efficient approach to solve the problem of PO constrained by MEDMs is the global treatment of both sensitivity analysis and PO. Model validation is an essential step following PO, which validates the efficiency of model calibration by analyzing and estimating the goodness-of-fit of the optimized model. Additionally, by focusing on the degree of impact of various factors on model skill, model uncertainty analysis can supply model users with a quantitative assessment of model confidence. Research on MEDMs is ongoing; however, improvement in model skill still lacks global treatments and its assessment is not integrated. Thus, the predictive performance of MEDMs is not strong and model uncertainties lack quantitative descriptions, limiting their application. Therefore, a large number of case studies concerning model skill should be performed to promote the development of a scientific and normative technical framework for the improvement of MEDM skill.
Investigating dynamic parameters in HWZPR ased on the experimental and calculated results
Energy Technology Data Exchange (ETDEWEB)
Nasrazadani, Zahra; Behfamia, Manochehar; Khosandi, Jamshid; Mirvakili, Mohammad [Reactors Research School, Nuclear Science And Technology Research Institute, Atomic Energy Organization of Iran, Esfahan (Iran, Islamic Republic of)
2016-10-15
The neutron decay constant, α, and effective delayed neutron fraction, β{sub eff}, are important parameters for the control of the dynamic behavior of nuclear reactors. For the heavy water zero power reactor (HWZPR), this document describes the measurements of the neutron decay constant by noise analysis methods, including variance to mean (VTM) ratio and endogenous pulse source (EPS) methods. The measured α is successively used to determine the experimental value of the effective delayed neutron fraction as well. According to the experimental results, β{sub eff} of the HWZPR reactor under study is equal to 7.84e-3. This value is finally used to validate the calculation of the effective delayed neutron fraction by the Monte Carlo methods that are discussed in the document. Using the Monte Carlo N-Particle (MCNP)-4C code, a β{sub eff} value of 7.58e-3 was obtained for the reactor under study. Thus, the relative difference between the β{sub eff} values determined experimentally and by Monte Carlo methods was estimated to be < 4%.
Directory of Open Access Journals (Sweden)
Chun-Liang Lu
2015-10-01
Full Text Available The optimized hybrid artificial intelligence model is a potential tool to deal with construction engineering and management problems. Support vector machine (SVM has achieved excellent performance in a wide variety of applications. Nevertheless, how to effectively reduce the training complexity for SVM is still a serious challenge. In this paper, a novel order-independent approach for instance selection, called the dynamic condensed nearest neighbor (DCNN rule, is proposed to adaptively construct prototypes in the training dataset and to reduce the redundant or noisy instances in a classification process for the SVM. Furthermore, a hybrid model based on the genetic algorithm (GA is proposed to simultaneously optimize the prototype construction and the SVM kernel parameters setting to enhance the classification accuracy. Several UCI benchmark datasets are considered to compare the proposed hybrid GA-DCNN-SVM approach with the previously published GA-based method. The experimental results illustrate that the proposed hybrid model outperforms the existing method and effectively improves the classification performance for the SVM.
Hansen, Clint; Venture, Gentiane; Rezzoug, Nasser; Gorce, Philippe; Isableu, Brice
2014-05-01
Over the last decades a variety of research has been conducted with the goal to improve the Body Segment Inertial Parameters (BSIP) estimations but to our knowledge a real validation has never been completely successful, because no ground truth is available. The aim of this paper is to propose a validation method for a BSIP identification method (IM) and to confirm the results by comparing them with recalculated contact forces using inverse dynamics to those obtained by a force plate. Furthermore, the results are compared with the recently proposed estimation method by Dumas et al. (2007). Additionally, the results are cross validated with a high velocity overarm throwing movement. Throughout conditions higher correlations, smaller metrics and smaller RMSE can be found for the proposed BSIP estimation (IM) which shows its advantage compared to recently proposed methods as of Dumas et al. (2007). The purpose of the paper is to validate an already proposed method and to show that this method can be of significant advantage compared to conventional methods.
Saha, Sourav; Mojumder, Satyajit; Mahboob, Monon; Islam, M. Zahabul
2016-07-01
Tungsten is a promising material and has potential use as battery anode. Tungsten nanowires are gaining attention from researchers all over the world for this wide field of application. In this paper, we investigated effect of temperature and geometric parameters (diameter and aspect ratio) on elastic properties of Tungsten nanowire. Aspect ratios (length to diameter ratio) considered are 8:1, 10:1, and 12:1 while diameter of the nanowire is varied from 1-4 nm. For 2 nm diameter sample (aspect ratio 10:1), temperature is varied (10K ~ 1500K) to observe elastic behavior of Tungsten nanowire under uniaxial tensile loading. EAM potential is used for molecular dynamic simulation. We applied constant strain rate of 109 s-1 to deform the nanowire. Elastic behavior is expressed through stress vs. strain plot. We also investigated the fracture mechanism of tungsten nanowire and radial distribution function. Investigation suggests peculiar behavior of Tungsten nanowire in nano-scale with double peaks in stress vs. strain diagram. Necking before final fracture suggests that actual elastic behavior of the material is successfully captured through atomistic modeling.
Institute of Scientific and Technical Information of China (English)
倪芝芳; 李玉民
1996-01-01
According to detonation theory and hydrodynamic principle, a physical model has been set up in this paper. Based on the model a methodology for calculating dynamic initial shock parameters such as shock pressure p,,, shock wave velosity Dm etc. of coupling charge on borehole wall has ben developed. The shock parameters have been calculated when high explosives works on granite, limestone and marble respectively. The magnitude of every parameter on borehole wall has been obtained from ignited dot to the end of borehole along axial direction. Some important conclusions are also gained.
The Grüneisen Parameter of NaCl at High Pressures and Temperatures: a Molecular Dynamics Study
Institute of Scientific and Technical Information of China (English)
CAI Ling-Cang; CHEN Qi-Feng; CUI Shou-Xin; JING Fu-Qian
2005-01-01
@@ The isotherms and Griineisen parameters are calculated by using the molecular dynamics (MD) method with an improved Tosi-Fumi pair potential. The results show that the approximate power law dependence of the Griineisen parameter on compression γ = γo( V/Vo )q, with q ≈ 1.078, holds in the temperature range from 298 to 1073K and pressure range from 0 to 60 GPa, and that the Griineisen parameter for a given density of 2.16g/cm3varies with temperature in a wind range from 300 to 10000K, expressed by γ = 1.052 + 0.582exp(-T/4878.56).
The post-Keplerian orbital representations of the relativistic two-body problem
Klioner, S. A.; Kopeikin, S. M.
1994-06-01
Orbital parameterizations of the relativstic two-body problem due to Brumberg, Damour-Deruelle, Epstein-Haugan, and Blandford-Teukolsky as well as osculating elements are compared. Exact relations between constants describing the orbit in the parameterizations are derived. It is shown that all the parameterizations in question are valid not only in general relativity, but in a generic class of relatvistic theories of gravity. The obtained results provide us with an additional check of consistency of different models used in timing of binary pulsars.
On the change of density of states in two-body interactions
Gao, Bo
2016-01-01
We derive a general relation in two-body scattering theory that more directly relates the change of density of states (DDOS) due to interaction to the shape of the potential. The relation allows us to infer certain global properties of the DDOS from the global properties of the potential. In particular, we show that DDOS is negative at all energies and for all partial waves, for potentials that are more repulsive than $+1/r^2$ everywhere. This behavior represents a different class of global properties of DDOS from that described by the Levinson's theorem.
Two-body decays of gluino at full one-loop level in the quark-flavour violating MSSM.
Eberl, Helmut; Ginina, Elena; Hidaka, Keisho
2017-01-01
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalisation is done in the [Formula: see text] scheme. The gluon and photon radiations are included by adding the corresponding three-body decay widths. We discuss the dependence of the gluino decay widths on the QFV parameters. The main dependence stems from the [Formula: see text]-[Formula: see text] mixing in the decays to up-type squarks, and from the [Formula: see text]-[Formula: see text] mixing in the decays to down-type squarks due to the strong constraints from B-physics on the other quark-flavour-mixing parameters. The full one-loop corrections to the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest [Formula: see text] squark. For the corresponding branching ratio the effect is somehow washed out by at least a factor of two. The electroweak corrections can be as large as 35% of the SUSY QCD corrections.
Two-body decays of gluino at full one-loop level in the quark-flavour violating MSSM
Energy Technology Data Exchange (ETDEWEB)
Eberl, Helmut; Ginina, Elena [Institut fuer Hochenergiephysik der Oesterreichischen Akademie der Wissenschaften, Vienna (Austria); Hidaka, Keisho [Tokyo Gakugei University, Department of Physics, Tokyo (Japan)
2017-03-15
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalisation is done in the DR scheme. The gluon and photon radiations are included by adding the corresponding three-body decay widths. We discuss the dependence of the gluino decay widths on the QFV parameters. The main dependence stems from the c{sub R}-t{sub R} mixing in the decays to up-type squarks, and from the s{sub R}-b{sub R} mixing in the decays to down-type squarks due to the strong constraints from B-physics on the other quark-flavour-mixing parameters. The full one-loop corrections to the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest u squark. For the corresponding branching ratio the effect is somehow washed out by at least a factor of two. The electroweak corrections can be as large as 35% of the SUSY QCD corrections. (orig.)
Shanmugam, Palanisamy; Varunan, Theenathayalan; Nagendra Jaiganesh, S. N.; Sahay, Arvind; Chauhan, Prakash
2016-06-01
Prediction of the curve of the absorption coefficient of colored dissolved organic matter (CDOM) and differentiation between marine and terrestrially derived CDOM pools in coastal environments are hampered by a high degree of variability in the composition and concentration of CDOM, uncertainties in retrieved remote sensing reflectance and the weak signal-to-noise ratio of space-borne instruments. In the present study, a hybrid model is presented along with empirical methods to remotely determine the amount and type of CDOM in coastal and inland water environments. A large set of in-situ data collected on several oceanographic cruises and field campaigns from different regional waters was used to develop empirical methods for studying the distribution and dynamics of CDOM, dissolved organic carbon (DOC) and salinity. Our validation analyses demonstrated that the hybrid model is a better descriptor of CDOM absorption spectra compared to the existing models. Additional spectral slope parameters included in the present model to differentiate between terrestrially derived and marine CDOM pools make a substantial improvement over those existing models. Empirical algorithms to derive CDOM, DOC and salinity from remote sensing reflectance data demonstrated success in retrieval of these products with significantly low mean relative percent differences from large in-situ measurements. The performance of these algorithms was further assessed using three hyperspectral HICO images acquired simultaneously with our field measurements in productive coastal and lagoon waters on the southeast part of India. The validation match-ups of CDOM and salinity showed good agreement between HICO retrievals and field observations. Further analyses of these data showed significant temporal changes in CDOM and phytoplankton absorption coefficients with a distinct phase shift between these two products. Healthy phytoplankton cells and macrophytes were recognized to directly contribute to the
Directory of Open Access Journals (Sweden)
Mingxin Ao
Full Text Available PURPOSE: Dynamic visual acuity (DVA is a relatively independent parameter for evaluating the ability to distinguish details of a moving target. The present study has been designed to discuss the extent to which age-related cataract impacts DVA in elderly individuals and to determine whether it could be restored after bilateral phacoemulsification combined with intraocular lens implantation surgery. METHODS: Twenty-six elderly cataract patients scheduled for binocular cataract surgery and 30 elderly volunteers without cataract were enrolled in the study. DVA at 15, 30, 60 and 90 degree per second (dps was assessed, and velocity-dependent visual acuity decreases between consecutive speed levels were calculated. RESULTS: Compared with the control group, the patient group exhibited significantly worse DVA performance at all speed levels (p<0.001, and the decreases in velocity-dependent visual acuity were more serious in the patient group at the intervals of 0-15 dps (p<0.001, 15-30 dps (p = 0.007 and 30-60 dps (p = 0.008. Postoperatively, DVA performance at every speed level in the patient group clearly improved (p<0.001 and recovered to levels compatible to the control group. The decrease in visual acuity with increasing speed was less pronounced than during the preoperative phase (p0-15 dps = 0.001, p15-30 dps<0.001 and p30-60 dps = 0.001 and became similar to that of the control group. The postoperative visual benefit regarding DVA was more pronounced than the improvement in static visual acuity (p15 dps = 0.001 and p<0.001 at 30 dps, 60 dps and 90 dps. CONCLUSIONS: The impact of age-related cataract on DVA was more severe than its effects on static visual acuity. After cataract surgery, not only static vision of the patients was restored markedly, but also the dynamic vision. DVA could be an important adjunct to the current evaluation system of functional vision, thereby meriting additional attention in clinical assessment.
Koeppe, Robert Allen
Positron computed tomography (PCT) is a diagnostic imaging technique that provides both three dimensional imaging capability and quantitative measurements of local tissue radioactivity concentrations in vivo. This allows the development of non-invasive methods that employ the principles of tracer kinetics for determining physiological properties such as mass specific blood flow, tissue pH, and rates of substrate transport or utilization. A physiologically based, two-compartment tracer kinetic model was derived to mathematically describe the exchange of a radioindicator between blood and tissue. The model was adapted for use with dynamic sequences of data acquired with a positron tomograph. Rapid estimation techniques were implemented to produce functional images of the model parameters by analyzing each individual pixel sequence of the image data. A detailed analysis of the performance characteristics of three different parameter estimation schemes was performed. The analysis included examination of errors caused by statistical uncertainties in the measured data, errors in the timing of the data, and errors caused by violation of various assumptions of the tracer kinetic model. Two specific radioindicators were investigated. ('18)F -fluoromethane, an inert freely diffusible gas, was used for local quantitative determinations of both cerebral blood flow and tissue:blood partition coefficient. A method was developed that did not require direct sampling of arterial blood for the absolute scaling of flow values. The arterial input concentration time course was obtained by assuming that the alveolar or end-tidal expired breath radioactivity concentration is proportional to the arterial blood concentration. The scale of the input function was obtained from a series of venous blood concentration measurements. The method of absolute scaling using venous samples was validated in four studies, performed on normal volunteers, in which directly measured arterial concentrations
Lika, K.; Kearney, M.R.; Freitas, V.; Veer, van der H.W.; Meer, van der J.; Wijsman, J.W.M.; Pecquerie, L.; Kooijman, S.A.L.M.
2011-01-01
The Dynamic Energy Budget (DEB) theory for metabolic organisation captures the processes of development, growth, maintenance, reproduction and ageing for any kind of organism throughout its life-cycle. However, the application of DEB theory is challenging because the state variables and parameters a
Lika, K.; Kearney, M.R.; Freitas, V.; van der Veer, H.W.; van der Meer, J.; Wijsman, J.W.M.; Pecquerie, L.; Kooijman, S.A.L.M.
2011-01-01
The Dynamic Energy Budget (DEB) theory for metabolic organisation captures the processes of development, growth, maintenance, reproduction and ageing for any kind of organism throughout its life-cycle. However, the application of DEB theory is challenging because the state variables and parameters a
DEFF Research Database (Denmark)
Tofts, P.S.; Brix, G; Buckley, D.L.
1999-01-01
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K...
Ludwig, C; Grimmer, S; Seyfarth, A; Maus, H-M
2012-09-21
The spring-loaded inverted pendulum (SLIP) model is a well established model for describing bouncy gaits like human running. The notion of spring-like leg behavior has led many researchers to compute the corresponding parameters, predominantly stiffness, in various experimental setups and in various ways. However, different methods yield different results, making the comparison between studies difficult. Further, a model simulation with experimentally obtained leg parameters typically results in comparatively large differences between model and experimental center of mass trajectories. Here, we pursue the opposite approach which is calculating model parameters that allow reproduction of an experimental sequence of steps. In addition, to capture energy fluctuations, an extension of the SLIP (ESLIP) is required and presented. The excellent match of the models with the experiment validates the description of human running by the SLIP with the obtained parameters which we hence call dynamical leg parameters.
Institute of Scientific and Technical Information of China (English)
Jian Zhang; Chu-Wei Zhou; Jia-Shou Zhuo
2011-01-01
The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory, dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples, it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence, which demonstrates that the presented method and the compiled procedure are correct and reliable.The project was supported by the National Natural Science Foundation of China ( 10472045.10772078 and 11072108 and the Science Foundation of NUAA(S0851-013).During parameters' iterative processes, the Powell theory is irrelevant with the calculation of finite curve strip element (FCSE) partial differentiation, which proves high computation efficiency of the studied method.
Improving the Volume Dependence of Two-Body Binding Energies Calculated with Lattice QCD
Davoudi, Zohreh
2011-01-01
Volume modifications to the binding of two-body systems in large cubic volumes of extent L depend upon the total momentum and exponentially upon the ratio of L to the size of the boosted system. Recent work by Bour et al determined the momentum dependence of the leading volume modifications to nonrelativistic systems with periodic boundary conditions imposed on the single-particle wavefunctions, enabling them to numerically determine the scattering of such bound states using a low-energy effective field theory and Luschers finite-volume method. The calculation of bound nuclear systems directly from QCD using Lattice QCD has begun, and it is important to reduce the systematic uncertainty introduced into such calculations by the finite spatial extent of the gauge-field configurations. We extend the work of Bour et al from nonrelativistic quantum mechanics to quantum field theory by generalizing the work of Luscher and of Gottlieb and Rummukainen to boosted two-body bound states. The volume modifications to bind...
Global solutions to the electrodynamic two-body problem on a straight line
Bauer, G.; Deckert, D.-A.; Dürr, D.; Hinrichs, G.
2017-06-01
The classical electrodynamic two-body problem has been a long standing open problem in mathematics. For motion constrained to the straight line, the interaction is similar to that of the two-body problem of classical gravitation. The additional complication is the presence of unbounded state-dependent delays in the Coulomb forces due to the finiteness of the speed of light. This circumstance renders the notion of local solutions meaningless, and therefore, straightforward ODE techniques cannot be applied. Here, we study the time-symmetric case, i.e., the Fokker-Schwarzschild-Tetrode (FST) equations, comprising both advanced and retarded delays. We extend the technique developed in Deckert and Hinrichs (J Differ Equ 260:6900-6929, 2016), where existence of FST solutions was proven on the half line, to ensure global existence—a result that had been obtained by Bauer (Ein Existenzsatz für die Wheeler-Feynman-Elektrodynamik, Herbert Utz Verlag, München, 1997). Due to the novel technique, the presented proof is shorter and more transparent but also relies on the idea to employ asymptotic data to characterize solutions.
Energy spectra of massive two-body decay products and mass measurement
Agashe, Kaustubh; Hong, Sungwoo; Kim, Doojin
2016-01-01
We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the SM particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial b...
Zhang, Yang; Peng, Yan; Sun, Jianliang; Zang, Yong
2017-05-01
The existence of rolling deformation area in the rolling mill system is the main characteristic which distinguishes the other machinery. In order to analyze the dynamic property of roll system's flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simultaneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through introducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the coupled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural deformation movement's mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment of dynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.
Zhang, Yang; Peng, Yan; Sun, Jianliang; Zang, Yong
2017-03-01
The existence of rolling deformation area in the rolling mill system is the main characteristic which distinguishes the other machinery. In order to analyze the dynamic property of roll system's flexural deformation, it is necessary to consider the transverse periodic movement of stock in the rolling deformation area which is caused by the flexural deformation movement of roll system simultaneously. Therefore, the displacement field of roll system and flow of metal in the deformation area is described by kinematic analysis in the dynamic system. Through introducing the lateral displacement function of metal in the deformation area, the dynamic variation of per unit width rolling force can be determined at the same time. Then the coupling law caused by the co-effect of rigid movement and flexural deformation of the system structural elements is determined. Furthermore, a multi-parameter coupling dynamic model of the roll system and stock is established by the principle of virtual work. More explicitly, the coupled motion modal analysis was made for the roll system. Meanwhile, the analytical solutions for the flexural deformation movement's mode shape functions of rolls are discussed. In addition, the dynamic characteristic of the lateral flow of metal in the rolling deformation area has been analyzed at the same time. The establishment of dynamic lateral displacement function of metal in the deformation area makes the foundation for analyzing the coupling law between roll system and rolling deformation area, and provides a theoretical basis for the realization of the dynamic shape control of steel strip.
Zi, Bin; Zhou, Bin
2016-07-01
For the prediction of dynamic response field of the luffing system of an automobile crane (LSOAAC) with random and interval parameters, a hybrid uncertain model is introduced. In the hybrid uncertain model, the parameters with certain probability distribution are modeled as random variables, whereas, the parameters with lower and upper bounds are modeled as interval variables instead of given precise values. Based on the hybrid uncertain model, the hybrid uncertain dynamic response equilibrium equation, in which different random and interval parameters are simultaneously included in input and output terms, is constructed. Then a modified hybrid uncertain analysis method (MHUAM) is proposed. In the MHUAM, based on random interval perturbation method, the first-order Taylor series expansion and the first-order Neumann series, the dynamic response expression of the LSOAAC is developed. Moreover, the mathematical characteristics of extrema of bounds of dynamic response are determined by random interval moment method and monotonic analysis technique. Compared with the hybrid Monte Carlo method (HMCM) and interval perturbation method (IPM), numerical results show the feasibility and efficiency of the MHUAM for solving the hybrid LSOAAC problems. The effects of different uncertain models and parameters on the LSOAAC response field are also investigated deeply, and numerical results indicate that the impact made by the randomness in the thrust of the luffing cylinder F is larger than that made by the gravity of the weight in suspension Q . In addition, the impact made by the uncertainty in the displacement between the lower end of the lifting arm and the luffing cylinder a is larger than that made by the length of the lifting arm L .
Hydrodynamic interactions between two bodies in waves in 3D time domain
Institute of Scientific and Technical Information of China (English)
WANG Jian-fang; LI Ji-de; CAI Xin-gong; TIAN Ming-qi; Hao Jin-feng
2005-01-01
In this paper, a 3D time domain technique is adopted to calculate the coupled hydrodynamic interaction between two bodies without flare in waves. For verifying the code, two same cylinders are selected to calculate coupled hydrodynamic effects by comparison with the results obtained by 3D frequency method which has been proved to be efficient for solving such problems. In order to improve efficiency of calculation, the effect of history time has been discussed, and an improved method is presented. Moreover, the effect of lateral separation distance is also discussed in detail. The technique developed here may serve as a more rigorous tool to analyze the related transient problems of two ships doing underway replenishment in waves.
One-body and Two-body Fractional Parentage Coefficients for Spinor Bose-Einstein Condensation
Institute of Scientific and Technical Information of China (English)
BAO Cheng-guang
2006-01-01
A very effective tool,namely,the analytical expression of the fractional parentage coefficients (FPC),is introduced in this paper to deal with the total spin states of N-body spinor bosonic systems,where N is supposed to be large and the spin of each boson is one.In particular,the analytical forms of the one-body and two-body FPC for the total spin states with {N} and {N-1,1} permutation symmetries have been derived.These coefficients facilitate greatly the calculation of related matrix elements,and they can be used even in the case of N →∞.Theyappear as a powerful tool for the establishment of an improved theory of spinor Bose-Einstein condensation,where the eigenstates have the total spin S and its Z-component being both conserved.
Charmless Hadronic Two-body Decays of $B_{u}$ and $B_{d}$ Mesons
Chen, Y H; Tseng, B; Yang, K C; Chen, Yaw-Hwang; Cheng, Hai-Yang; Yang, Kwei-Chou
1999-01-01
Two-body charmless nonleptonic decays of B_u and B_d mesons are studied within the framework of generalized factorization in which the effective Wilson coefficients $c^{eff}_i$ are renormalization-scale and -scheme independent while factorization is applied to the tree-level hadronic matrix elements. Contrary to previous studies, our $c_i^{eff}$ do not suffer from gauge and infrared problems. Nonfactorizable effects are parametrized in terms of N_c(LL) and N_c(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Tree and penguin transitions are classified into six different classes. The data of $B^-\\to\\rho^0\\pi^-$ and $B^-\\to\\phi K^-$ clearly indicate that $N_c(LR)\
Rivera, R.; Villarroel, D.
1997-11-01
An exactly solvable two-body problem dealing with the Lorentz-Dirac equation is constructed in this paper. It corresponds to the motion of two identical charges rotating at opposite ends of a diameter, in a fixed circle, at constant angular velocity. The external electromagnetic field that allows this motion consists of a tangential time-independent electric field with a fixed value over the orbit circle, and a homogeneous time-independent magnetic field that points orthogonally to the orbit plane. Because of the geometrical symmetries of the charges' motion, in this case it is possible to obtain the rate of radiation emitted by the charges directly from the equation of motion. The rate of radiation is also calculated by studying the energy flux across a sphere of a very large radius, using the far retarded fields of the charges. Both calculations lead to the same result, in agreement with energy conservation.
Parametric Study of Two-Body Floating-Point Wave Absorber
Institute of Scientific and Technical Information of China (English)
Atena Amiri; Roozbeh Panahi; Soheil Radfar
2016-01-01
In this paper, we present a comprehensive numerical simulation of a point wave absorber in deep water. Analyses are performed in both the frequency and time domains. The converter is a two-body floating-point absorber (FPA) with one degree of freedom in the heave direction. Its two parts are connected by a linear mass-spring-damper system. The commercial ANSYS-AQWA software used in this study performs well in considering validations. The velocity potential is obtained by assuming incompressible and irrotational flow. As such, we investigated the effects of wave characteristics on energy conversion and device efficiency, including wave height and wave period, as well as the device diameter, draft, geometry, and damping coefficient. To validate the model, we compared our numerical results with those from similar experiments. Our study results can clearly help to maximize the converter’s efficiency when considering specific conditions.
Entropy theorems in classical mechanics, general relativity, and the gravitational two-body problem
Oltean, Marius; Bonetti, Luca; Spallicci, Alessandro D. A. M.; Sopuerta, Carlos F.
2016-09-01
In classical Hamiltonian theories, entropy may be understood either as a statistical property of canonical systems or as a mechanical property, that is, as a monotonic function of the phase space along trajectories. In classical mechanics, there are theorems which have been proposed for proving the nonexistence of entropy in the latter sense. We explicate, clarify, and extend the proofs of these theorems to some standard matter (scalar and electromagnetic) field theories in curved spacetime, and then we show why these proofs fail in general relativity; due to properties of the gravitational Hamiltonian and phase space measures, the second law of thermodynamics holds. As a concrete application, we focus on the consequences of these results for the gravitational two-body problem, and in particular, we prove the noncompactness of the phase space of perturbed Schwarzschild-Droste spacetimes. We thus identify the lack of recurring orbits in phase space as a distinct sign of dissipation and hence entropy production.
Non-Collision Singularities in the Planar Two-Center-Two-Body Problem
Xue, Jinxin; Dolgopyat, Dmitry
2016-08-01
In this paper, we study a restricted four-body problem called the planar two-center-two-body problem. In the plane, we have two fixed centers Q 1 and Q 2 of masses 1, and two moving bodies Q 3 and Q 4 of masses {μ≪ 1}. They interact via Newtonian potential. Q 3 is captured by Q 2, and Q 4 travels back and forth between two centers. Based on a model of Gerver, we prove that there is a Cantor set of initial conditions that lead to solutions of the Hamiltonian system whose velocities are accelerated to infinity within finite time avoiding all earlier collisions. This problem is a simplified model for the planar four-body problem case of the Painlevé conjecture.
Low-Thrust Orbital Transfers in the Two-Body Problem
Directory of Open Access Journals (Sweden)
A. A. Sukhanov
2012-01-01
Full Text Available Low-thrust transfers between given orbits within the two-body problem are considered; the thrust is assumed power limited. A simple method for obtaining the transfer trajectories based on the linearization of the motion near reference orbits is suggested. Required calculation accuracy can be reached by means of use of a proper number of the reference orbits. The method may be used in the case of a large number of the orbits around the attracting center; no averaging is necessary in this case. The suggested method also is applicable to the cases of partly given final orbit and if there are constraints on the thrust direction. The method gives an optimal solution to the linearized problem which is not optimal for the original nonlinear problem; the difference between the optimal solutions to the original and linearized problems is estimated using a numerical example. Also examples illustrating the method capacities are given.
Calculation of the Two-body T-matrix in Configuration Space
Rawitscher, George
2007-01-01
A spectral integral method (IEM) for solving the two-body Schroedinger equation in configuration space is generalized to the calculation of the corresponding T-matrix. It is found that the desirable features of the IEM, such as the economy of mesh-points for a given required accuracy, are carried over also to the solution of the T-matrix. However the algorithm is considerably more complex, because the T-matrix is a function of two variables r and r', rather than only one variable r, and has a slope discontinuity at r=r'. For a simple exponential potential an accuracy of 7 significant figures is achieved, with the number N of Chebyshev support points in each partition equal to 17. For a potential with a large repulsive core, such as the potential between two He atoms, the accuracy decreases to 4 significant figures, but is restored to 7 if N is increased to 65.
Branching ratios for pbarp annihilation at rest into two-body final states
Abele, A; Amsler, Claude; Baker, C A; Barnett, B M; Batty, C J; Benayoun, M; Bischoff, S; Blüm, P; Braune, K; Bugg, D V; Case, T; Crowe, K M; Degener, T; Doser, Michael; Dünnweber, W; Engelhardt, D; Faessler, M A; Giarritta, P; Haddock, R P; Heinsius, F H; Heinzelmann, M; Herbstrith, A; Herz, M; Hessey, N P; Hidas, P; Hodd, C; Holtzhaussen, C; Jamnik, D; Kalinowsky, H; Kammel, P; Kisiel, J; Klempt, E; Koch, H; Kunze, M; Kurilla, U; Lakata, M; Landua, Rolf; Matthäy, H; McCrady, R; Meier, J; Meyer, C A; Montanet, Lucien; Ouared, R; Peters, K; Pick, B; Ratajczak, M; Regenfus, C; Röthel, W; Spanier, S; Stöck, H; Strassburger, C; Strohbusch, U; Suffert, Martin; Suh, J S; Thoma, U; Tischhäuser, M; Uman, I; Völcker, C; Wallis-Plachner, S; Walther, D; Wiedner, U; Wittmack, K; Zou, B S
2001-01-01
Measurements of two-body branching ratios for pbarp annihilations at rest in liquid and gaseous (12 rho sub S sub T sub P) hydrogen are reported. Channels studied are pbarp-> pi sup 0 pi sup 0 ,pi sup 0 eta, K sup 0 sub S K sup 0 sub L , K sup + K sup -. The branching ratio for the pi sup 0 pi sup 0 channel in liquid H sub 2 is measured to be (6.14+-0.40)x10 sup - sup 4. The results are compared with those from other experiments. The fraction of P-state annihilation for a range of target densities from 0.002 rho sub S sub T sub P to liquid H sub 2 is determined. Values obtained include 0.11+-0.02 in liquid H sub 2 and 0.48+-0.04 in 12 rho sub S sub T sub P H sub 2 gas.
Iorio, Lorenzo
2013-01-01
By phenomenologically assuming a slow temporal variation of the percent acceleration rate $\\ddot S S^{-1}$ of the cosmic scale factor $S(t)$, it is shown that the orbit of a local binary undergoes a secular expansion. To first order in the power expansion of $\\ddot S S^{-1}$ around the present epoch $t_0$, a non-vanishing shift per orbit $\\left\\langle\\Delta r\\right\\rangle$ of the two-body relative distance $r$ occurs for eccentric trajectories. A general relativistic expression, which turns out to be cubic in the Hubble parameter $H_0$ at the present epoch, is explicitly calculated for it in the case of matter-dominated epochs with Dark Energy. For a highly eccentric Oort comet orbit with period $P_{\\rm b}\\approx 31$ Myr, the general relativistic distance shift per orbit turns out to be of the order of $\\left\\langle\\Delta r\\right\\rangle\\approx 70$ km. For the Large Magellanic Cloud, assumed on a bound elliptic orbit around the Milky Way, the shift per orbit is of the order of $\\left\\langle\\Delta r\\right\\rangl...
Two-body wear of dental porcelain and substructure oxide ceramics.
Rosentritt, Martin; Preis, Verena; Behr, Michael; Hahnel, Sebastian; Handel, Gerhard; Kolbeck, Carola
2012-06-01
The aim of this in vitro study was to investigate the two-body wear of different ceramics. Two-body wear tests were performed in a chewing simulator with steatite and enamel antagonists, respectively. Specimens were loaded in a pin-on-block design with a vertical load of 50 N for 1.2 × 10(5) cycles; (f = 1.6 Hz; lateral movement, 1 mm; mouth opening: 2 mm). Human enamel was used as a reference. Three zirconia ceramics, three veneering porcelains, two glass-infiltrated and one lithium disilicate ceramic were investigated. Veneering and lithium disilicate ceramics were glazed before testing. Surface roughness Ra (SP6, Perthen-Feinprüf, G) and wear depth were determined using a 3D scanner (Laserscan 3D, Willytec, G). SEM (Quanta FEG 400, FEI, USA) pictures of the worn specimens and antagonists were made for evaluating wear performance. Veneering porcelain provided wear traces between 71.2 and 124.1 μm (enamel antagonist) and 117.4 and 274.1 μm (steatite). Wear of the steatite antagonists varied between 0.618 and 2.85 mm². No wear was found for zirconia and glass-infiltrated substructure ceramics. Also, no wear was found for the corresponding antagonists. Wear of specimens and antagonists was strongly material dependent. No visible wear was found on zirconia and glass-infiltrated ceramics. Porcelain and lithium disilicate ceramic showed a comparable or lower wear than the enamel reference. Antagonist wear was found to be lower when specimens were made of substructure oxide ceramics instead of veneering porcelain. From the point of wear testing, zirconia may be used for the fabrication of fixed dental prosthesis without veneering.
Street, K. W. Jr.; Kobrick, R. L.; Klaus, D. M.
2011-01-01
A limitation has been identified in the existing test standards used for making controlled, two-body abrasion scratch measurements based solely on the width of the resultant score on the surface of the material. A new, more robust method is proposed for analyzing a surface scratch that takes into account the full three-dimensional profile of the displaced material. To accomplish this, a set of four volume- displacement metrics was systematically defined by normalizing the overall surface profile to denote statistically the area of relevance, termed the Zone of Interaction. From this baseline, depth of the trough and height of the plowed material are factored into the overall deformation assessment. Proof-of-concept data were collected and analyzed to demonstrate the performance of this proposed methodology. This technique takes advantage of advanced imaging capabilities that allow resolution of the scratched surface to be quantified in greater detail than was previously achievable. When reviewing existing data analysis techniques for conducting two-body abrasive scratch tests, it was found that the ASTM International Standard G 171 specified a generic metric based only on visually determined scratch width as a way to compare abraded materials. A limitation to this method was identified in that the scratch width is based on optical surface measurements, manually defined by approximating the boundaries, but does not consider the three-dimensional volume of material that was displaced. With large, potentially irregular deformations occurring on softer materials, it becomes unclear where to systematically determine the scratch width. Specifically, surface scratches on different samples may look the same from a top view, resulting in an identical scratch width measurement, but may vary in actual penetration depth and/or plowing deformation. Therefore, two different scratch profiles would be measured as having identical abrasion properties, although they differ
DEFF Research Database (Denmark)
Maragakis, Paul; Lindorff-Larsen, Kresten; Eastwood, Michael P
2008-01-01
methods. However, apparent systematic discrepancies between order parameters extracted from simulations and experiments are common, particularly for elements of noncanonical secondary structure. In this paper, results from a 1.2 micros explicit solvent MD simulation of the protein ubiquitin are compared...... with previously determined backbone order parameters derived from NMR relaxation experiments [Tjandra, N.; Feller, S. E.; Pastor, R. W.; Bax, A. J. Am. Chem. Soc. 1995, 117, 12562-12566]. The simulation reveals fluctuations in three loop regions that occur on time scales comparable to or longer than...
White, Andrew; Bowers, Roger G
2005-01-01
We determine the adaptive dynamics of a general Lotka-Volterra system containing an intraspecific parameter dependency--in the form of an explicit functional trade-off between evolving parameters--and interspecific parameter dependencies--arising from modelling species interactions. We develop expressions for the fitness of a mutant strategy in a multi-species resident environment, the position of the singular strategy in such systems and the non-mixed second-order partial derivatives of the mutant fitness. These expressions can be used to determine the evolutionary behaviour of the system. The type of behaviour expected depends on the curvature of the trade-off function and can be interpreted in a biologically intuitive manner using the rate of acceleration/deceleration of the costs implicit in the trade-off function. We show that for evolutionary branching to occur we require that one (or both) of the traded-off parameters includes an interspecific parameter dependency and that the trade-off function has weakly accelerating costs. This could have important implications for understanding the type of mechanisms that cause speciation. The general theory is motivated by using adaptive dynamics to examine evolution in a predator-prey system. The applicability of the general theory as a tool for examining specific systems is highlighted by calculating the evolutionary behaviour in a three species (prey-predator-predator) system.
Directory of Open Access Journals (Sweden)
D. Sarsri
2016-03-01
Full Text Available This paper presents a methodological approach to compute the stochastic eigenmodes of large FE models with parameter uncertainties based on coupling of second order perturbation method and component mode synthesis methods. Various component mode synthesis methods are used to optimally reduce the size of the model. The statistical first two moments of dynamic response of the reduced system are obtained by the second order perturbation method. Numerical results illustrating the accuracy and efficiency of the proposed coupled methodological procedures for large FE models with uncertain parameters are presented.
Helgesson, J; Ekman, J; Helgesson, Johan; Ghetti, Roberta; Jorgen Ekman
2006-01-01
From velocity-gated small-angle correlation functions the emission chronology can be deduced for non-identical particles, if the emission is independent. This is not the case for non-identical particles that originate from two-body decay of fragments. Experimental results may contain contributions from both independent emission and two-body decay, so care is needed in interpreting the velocity-gated correlation functions. It is shown that in some special cases, it is still possible to deduce the emission chronology, even if there is a contribution from two-body decay.
Energy Technology Data Exchange (ETDEWEB)
Aerts, Hugo J W L [Department of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht University, Maastricht (Netherlands); Jaspers, K; Backes, Walter H, E-mail: w.backes@mumc.nl [Department of Radiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center (MUMC), Maastricht (Netherlands)
2011-09-07
Dynamic contrast-enhanced magnetic resonance imaging is increasingly applied for tumour diagnosis and early evaluation of therapeutic responses over time. However, the reliability of pharmacokinetic parameters derived from DCE-MRI is highly dependent on the experimental settings. In this study, the effect of sampling frequency (f{sub s}) and duration on the precision of pharmacokinetic parameters was evaluated based on system identification theory and computer simulations. Both theoretical analysis and simulations showed that a higher value of the pharmacokinetic parameter K{sup trans} required an increasing sampling frequency. For instance, for similar results, a relatively low f{sub s} of 0.2 Hz was sufficient for a low K{sup trans} of 0.1 min{sup -1}, compared to a high f{sub s} of 3 Hz for a high K{sup trans} of 0.5 min{sup -1}. For the parameter v{sub e}, a decreasing value required a higher sampling frequency. A sampling frequency below 0.1 Hz systematically resulted in imprecise estimates for all parameters. For the K{sup trans} and v{sub e} parameters, the sampling duration should be above 2 min, but durations of more than 7 min do not further improve parameter estimates.
Aerts, Hugo J. W. L.; Jaspers, K.; Backes, Walter H.
2011-09-01
Dynamic contrast-enhanced magnetic resonance imaging is increasingly applied for tumour diagnosis and early evaluation of therapeutic responses over time. However, the reliability of pharmacokinetic parameters derived from DCE-MRI is highly dependent on the experimental settings. In this study, the effect of sampling frequency (fs) and duration on the precision of pharmacokinetic parameters was evaluated based on system identification theory and computer simulations. Both theoretical analysis and simulations showed that a higher value of the pharmacokinetic parameter Ktrans required an increasing sampling frequency. For instance, for similar results, a relatively low fs of 0.2 Hz was sufficient for a low Ktrans of 0.1 min-1, compared to a high fs of 3 Hz for a high Ktrans of 0.5 min-1. For the parameter ve, a decreasing value required a higher sampling frequency. A sampling frequency below 0.1 Hz systematically resulted in imprecise estimates for all parameters. For the Ktrans and ve parameters, the sampling duration should be above 2 min, but durations of more than 7 min do not further improve parameter estimates.
De Groote, F; Van Campen, A; Jonkers, I; De Schutter, J
2010-07-20
We assessed and compared sensitivities of dynamic simulations to musculotendon (MT) parameters for gait and dynamometer experiments. Our aim with this comparison was to investigate whether dynamometer experiments could provide information about MT-parameters that are important to reliably study MT-function during gait. This would mean that dynamometer experiments could be used to estimate these parameters. Muscle contribution to the joint torque (MT-torque) rather than relative MT-force primarily affects the resulting gait pattern and torque measured by the dynamometer. In contrast to recent studies, therefore, we assessed the sensitivity of the MT-torque, rather than the sensitivity of the relative MT-force. Based on sensitivity of the MT-torque to a parameter perturbation, MT-parameters of the knee flexors and extensors were classified in three categories: low, medium, and high. For gait, classification was based on the average sensitivity during a gait cycle. For isometric and isokinetic dynamometer experiments, classification was based on the highest sensitivity found in the experiments. The calculated muscle contributions to the knee torque during gait and dynamometer experiments had a high sensitivity to only a limited number of MT-parameters of the knee flexors and extensors, suggesting that not all MT-parameters need to be estimated. In general, the highest sensitivity was found for tendon slack length. However, for some muscles the sensitivity to the optimal fibre length or the maximal isometric muscle force was also high or medium. The classification of the individual MT-parameters for gait and dynamometer experiments was largely similar. We therefore conclude that dynamometer experiments provide information about MT-parameters important to reliably study MT-function during gait, so that subject-specific estimates of MT-parameters could be made based on dynamometer experiments.
Tassis, Konstantinos; Yorke, Harold W; Turner, Neal
2011-01-01
We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores, and explore the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of initial magnetic support, and non-magnetic cores, with varying collapse delay times. We explore, through a parameter study, the competing effects of various model parameters in the evolving molecular abundances, including the elemental C/O ratio, the temperature, and the cosmic-ray ionization rate. We find that different models show their largest quantitative differences at the center of the core, whereas the outer layers, which evolve slower, have abundances which are severely degenerate among different dynamical models. There is a large range of possible abundance values for different models at a fixed evolutionary stage (central density), which demonstrates the large potential of chemical differentiation in prestellar cores. However, degeneracies among different models, compou...
Chen, Yung-Chuan; Tu, Yuan-Kun; Zhuang, Jun-Yan; Tsai, Yi-Jung; Yen, Cheng-Yo; Hsiao, Chih-Kun
2017-03-28
A three-dimensional dynamic elastoplastic finite element model was constructed and experimentally validated and was used to investigate the parameters which influence bone temperature during drilling, including the drill speed, feeding force, drill bit diameter, and bone density. Results showed the proposed three-dimensional dynamic elastoplastic finite element model can effectively simulate the temperature elevation during bone drilling. The bone temperature rise decreased with an increase in feeding force and drill speed, however, increased with the diameter of drill bit or bone density. The temperature distribution is significantly affected by the drilling duration; a lower drilling speed reduced the exposure duration, decreases the region of the thermally affected zone. The constructed model could be applied for analyzing the influence parameters during bone drilling to reduce the risk of thermal necrosis. It may provide important information for the design of drill bits and surgical drilling powers.
DEFF Research Database (Denmark)
Schäfer, L.; Yu, C.; Teppen, B.J.;
1999-01-01
In the context of a long-term program involving molecular dynamics simulations of adsorption phenomena at the clay mineral/aqueous solution interface, we are testing the viability of combining a force field that we developed specificially for clays with other, independently derived potential...... parameters for molecular species which are important in clay adsorption. For the current study the importance of variations in the potential parameters of water were investigated and polarization effects on oxygen studied as a function of intermolecular interactions. For this purpose ab initio MP2/6-311GG...... atomic charges were determined for several oligomers of water and for the water dimer at different intermolecular separations. Charge variations of up to ~0.1 electron charge unit on oxygen are found and, together with changes in van der Waals constants, their significance for dynamics simulations...
Directory of Open Access Journals (Sweden)
Mothanna Y. Abd
2012-01-01
Full Text Available A beam-type absorber has been known as one of the dynamic vibration absorbers used to suppress excessive vibration of an engineering structure. This paper studies an absorbing beam which is attached through a visco-elastic layer on a primary beam structure. Solutions of the dynamic response are presented at the midspan of the primary and absorbing beams in simply supported edges subjected to a stationary harmonic load. The effect of structural parameters, namely, rigidity ratio, mass ratio, and damping of the layer and the structure as well as the layer stiffness on the response is investigated to reduce the vibration amplitude at the fundamental frequency of the original single primary beam. It is found that this can considerably reduce the amplitude at the corresponding troublesome frequency, but compromised situation should be noted by controlling the structural parameters. The model is also validated with measured data with reasonable agreement.
One Form of Lyapunov Operator for Stochastic Dynamic System with Markov Parameters
Directory of Open Access Journals (Sweden)
Taras Lukashiv
2016-01-01
Full Text Available The form of weak infinitesimal operator of Lyapunov type on solutions of stochastic dynamic systems of random structure with constant delay which exist under the action of Markov perturbations is obtained.
Pirc, Gordana; Stare, Jernej; Mavri, Janez; Vianello, Robert
2014-01-01
Chemometric statistical approaches involving multiple linear regression (MLR) and principal compo-nent analysis (PCA) were employed on a set of 42 distinct snapshot structures of the physiological histamine monocation in aqueous solution along the Car-Parrinello molecular dynamics trajectory, in order to obtain a better insight into the relationship between the geometry parameters of the system and the resulting νNH stretching frequencies. A simple 2D linear regression of νNH with Namino•••Ow...
Institute of Scientific and Technical Information of China (English)
ZHANG Shan-Qing; LI Zhi-Bin
2004-01-01
@@ The master equation of a one-dimensional lattice-gas model with order preservation where the occupation probabilities of sites corresponding to Bose statistics as a consequence of the prescribed dynamics is studied with the potential symmetry method. The infinite-parameter potential symmetry and a new exact solution are obtained. The result illustrates that there remains the possibility of the above nonlinear equation to a linear partial differential equation by a non-invertible mapping.
Limit cycles by FEM for a one - parameter dynamical system associated to the Luo - Rudy I model
Bichir, Cătălin Liviu; Amuzescu, Bogdan; Nistor, Gheorghe; Popescu, Marin; Flonta, Maria-Luiza; Corlan, Alexandru Dan; Svab, Istvan
2011-01-01
An one - parameter dynamical system is associated to the mathematical problem governing the membrane excitability of a ventricular cardiomyocyte, according to the Luo-Rudy I model. Limit cycles are described by the solutions of an extended system. A finite element method time approximation (FEM) is used in order to formulate the approximate problem. Starting from a Hopf bifurcation point, approximate limit cycles are obtained, step by step, using an arc-length-continuation method and Newton's method. Some numerical results are presented.
Energy Technology Data Exchange (ETDEWEB)
Liu, Qing; Shi, Chaowei [Hefei National Laboratory for Physical Sciences at The Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Yu, Lu [Hefei National Laboratory for Physical Sciences at The Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui, 230031 (China); Zhang, Longhua [Hefei National Laboratory for Physical Sciences at The Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Xiong, Ying, E-mail: yxiong73@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at The Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Tian, Changlin, E-mail: cltian@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at The Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 (China); High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui, 230031 (China)
2015-02-13
Internal backbone dynamic motions are essential for different protein functions and occur on a wide range of time scales, from femtoseconds to seconds. Molecular dynamic (MD) simulations and nuclear magnetic resonance (NMR) spin relaxation measurements are valuable tools to gain access to fast (nanosecond) internal motions. However, there exist few reports on correlation analysis between MD and NMR relaxation data. Here, backbone relaxation measurements of {sup 15}N-labeled SH3 (Src homology 3) domain proteins in aqueous buffer were used to generate general order parameters (S{sup 2}) using a model-free approach. Simultaneously, 80 ns MD simulations of SH3 domain proteins in a defined hydrated box at neutral pH were conducted and the general order parameters (S{sup 2}) were derived from the MD trajectory. Correlation analysis using the Gromos force field indicated that S{sup 2} values from NMR relaxation measurements and MD simulations were significantly different. MD simulations were performed on models with different charge states for three histidine residues, and with different water models, which were SPC (simple point charge) water model and SPC/E (extended simple point charge) water model. S{sup 2} parameters from MD simulations with charges for all three histidines and with the SPC/E water model correlated well with S{sup 2} calculated from the experimental NMR relaxation measurements, in a site-specific manner. - Highlights: • Correlation analysis between NMR relaxation measurements and MD simulations. • General order parameter (S{sup 2}) as common reference between the two methods. • Different protein dynamics with different Histidine charge states in neutral pH. • Different protein dynamics with different water models.
Soil Parameter Identification for Wheel-terrain Interaction Dynamics and Traversability Prediction
Institute of Scientific and Technical Information of China (English)
Suksun Hutangkabodee; Yahya Hashem Zweiri; Lakmal Dasarath Seneviratne; Kaspar Althoefer
2006-01-01
This paper presents a novel technique for identifying soil parameters for a wheeled vehicle traversing unknown terrain. The identified soil parameters are required for predicting vehicle drawbar pull and wheel drive torque, which in turn can be used for traversability prediction, traction control, and performance optimization of a wheeled vehicle on unknown terrain. The proposed technique is based on the Newton Raphson method. An approximated form of a wheel-soil interaction model based on Composite Simpson's Rule is employed for this purpose. The key soil parameters to be identified are internal friction angle, shear deformation modulus, and lumped pressure-sinkage coefficient. The fourth parameter, cohesion, is not too relevant to vehicle drawbar pull, and is assigned an average value during the identification process. Identified parameters are compared with known values, and shown to be in agreement. The identification method is relatively fast and robust.The identified soil parameters can effectively be used to predict drawbar pull and wheel drive torque with good accuracy.The use of identified soil parameters to design a traversability criterion for wheeled vehicles traversing unknown terrain is presented.
Directory of Open Access Journals (Sweden)
Lorenzo Iorio
2014-01-01
Full Text Available By phenomenologically assuming a slow temporal variation of the percent acceleration rate S̈S -1 of the cosmic scale factor S(t, it is shown that the orbit of a local binary undergoes a secular expansion. To first order in the power expansion of S̈S -1 around the present epoch t0, a non-vanishing shift per orbit (Δr of the two-body relative distance r occurs for eccentric trajectories. A general relativistic expression, which turns out to be cubic in the Hubble parameter H0 at the present epoch, is explicitly calculated for it in the case of matter-dominated epochs with Dark Energy. For a highly eccentric Oort comet orbit with period Pb ≈ 31 Myr, the general relativistic distance shift per orbit turns out to be of the order of (Δr ≈ 70 km. For the Large Magellanic Cloud, assumed on a bound elliptic orbit around the Milky Way, the shift per orbit is of the order of (Δr ≈ 2–4 pc. Our result has a general validity since it holds in any cosmological model admitting the Hubble law and a slowly varying S̈S-1(t. More generally, it is valid for an arbitrary Hooke-like extra-acceleration whose “elastic” parameter κ is slowly time-dependent, irrespectively of the physical mechanism which may lead to it. The coefficient κ1 of the first-order term of the power expansion of κ(t can be preliminarily constrained in a model-independent way down to a κ1 ≲ 2 x 10-13 year-3 level from latest Solar System’s planetary observations. The radial velocities of the double lined spectroscopic binary ALPHA Cen AB yield κ1 ≲ 10-8 year-3.
Iorio, Lorenzo
2014-01-01
By phenomenologically assuming a slow temporal variation of the percent acceleration rate S̈S -1 of the cosmic scale factor S(t), it is shown that the orbit of a local binary undergoes a secular expansion. To first order in the power expansion of S̈S -1 around the present epoch t0, a non-vanishing shift per orbit (Δr) of the two-body relative distance r occurs for eccentric trajectories. A general relativistic expression, which turns out to be cubic in the Hubble parameter H0 at the present epoch, is explicitly calculated for it in the case of matter-dominated epochs with Dark Energy. For a highly eccentric Oort comet orbit with period Pb ≈ 31 Myr, the general relativistic distance shift per orbit turns out to be of the order of (Δr) ≈ 70 km. For the Large Magellanic Cloud, assumed on a bound elliptic orbit around the Milky Way, the shift per orbit is of the order of (Δr) ≈ 2-4 pc. Our result has a general validity since it holds in any cosmological model admitting the Hubble law and a slowly varying S̈S-1(t). More generally, it is valid for an arbitrary Hooke-like extra-acceleration whose "elastic" parameter κ is slowly time-dependent, irrespectively of the physical mechanism which may lead to it. The coefficient κ1 of the first-order term of the power expansion of κ(t) can be preliminarily constrained in a model-independent way down to a κ1 ≤ 2 x 10-13 year-3 level from latest Solar System's planetary observations. The radial velocities of the double lined spectroscopic binary ALPHA Cen AB yield κ1 ≤ 10-8 year-3.
Glover, K.; Willems, J. C.
1973-01-01
Consider the situation in which the unknown parameters of a stationary linear system may be parametrized by a set of unknown parameters. The question thus arises of when such a set of parameters can be uniquely identified on the basis of observed data. This problem is considered here both in the case of input and output observations and in the case of output observations in the presence of a white noise input. Conditions for local identifiability are derived for both situations and a sufficient condition for global identifiability is given for the former situation, i.e., when simultaneous input and output observations are available.
Directory of Open Access Journals (Sweden)
B. Scharnagl
2011-10-01
Full Text Available In situ observations of soil water state variables under natural boundary conditions are often used to estimate the soil hydraulic properties. However, many contributions to the soil hydrological literature have demonstrated that the information content of such data is insufficient to accurately and precisely estimate all the soil hydraulic parameters. In this case study, we explored to which degree prior information about the soil hydraulic parameters can help improve parameter identifiability in inverse modelling of in situ soil water dynamics under natural boundary conditions. We used percentages of sand, silt, and clay as input variables to the ROSETTA pedotransfer function that predicts the parameters in the van Genuchten-Mualem (VGM model of the soil hydraulic functions. To derive additional information about the correlation structure of the predicted parameters, which is not readily provided by ROSETTA, we employed a Monte Carlo approach. We formulated three prior distributions that incorporate to different extents the prior information about the VGM parameters derived with ROSETTA. The inverse problem was posed in a formal Bayesian framework and solved using Markov chain Monte Carlo (MCMC simulation with the DiffeRential Evolution Adaptive Metropolis (DREAM algorithm. Synthetic and real-world soil water content data were used to illustrate the approach. The results of this study demonstrated that prior information about the soil hydraulic parameters significantly improved parameter identifiability and that this approach was effective and robust, even in case of biased prior information. To be effective and robust, however, it was essential to use a prior distribution that incorporates information about parameter correlation.
Zhidkov, K P; Fedorova, L A; Polevshchikov, A V; Nazarov, P G
1992-03-01
The influence of autotransfusions of hemosorbent-treated blood on parameters of DNA-synthetic activity of blood lymphocytes was studied in 114 patients with gastric ulcer. A statistically significant increase in parameters of DNA-synthetic activity of lymphocytes was recorded simultaneously with the appearance of morphological signs of blast transformation on electrograms. A conclusion has been made on association of lymphocyte blastogenesis under the influence of autotransfusions with the process of ulcerous sanagenesis acceleration.
Microbial dynamics in a glycolate fed biogas reactor influenced by abiotic parameters
Reinert, Susann
2015-01-01
Much research was performed in order to find alternative energy sources. In the new concept presented in this thesis, methane was produced by a microbial consortium which is fed only by glycolate excreted by photosynthetic algae. It was unknown how the biogas production and the process stability are influenced by certain parameter shifts in glycolate feed, pH of the feed, oxygen input and temperature. Therefore, different parameter changes were applied to the reactor...
Wang, Hong; Wang, Xicheng; Li, Zheng; Li, Keqiu
2016-01-01
The metabolic network model allows for an in-depth insight into the molecular mechanism of a particular organism. Because most parameters of the metabolic network cannot be directly measured, they must be estimated by using optimization algorithms. However, three characteristics of the metabolic network model, i.e., high nonlinearity, large amount parameters, and huge variation scopes of parameters, restrict the application of many traditional optimization algorithms. As a result, there is a growing demand to develop efficient optimization approaches to address this complex problem. In this paper, a Kriging-based algorithm aiming at parameter estimation is presented for constructing the metabolic networks. In the algorithm, a new infill sampling criterion, named expected improvement and mutual information (EI&MI), is adopted to improve the modeling accuracy by selecting multiple new sample points at each cycle, and the domain decomposition strategy based on the principal component analysis is introduced to save computing time. Meanwhile, the convergence speed is accelerated by combining a single-dimensional optimization method with the dynamic coordinate perturbation strategy when determining the new sample points. Finally, the algorithm is applied to the arachidonic acid metabolic network to estimate its parameters. The obtained results demonstrate the effectiveness of the proposed algorithm in getting precise parameter values under a limited number of iterations.
Energy Technology Data Exchange (ETDEWEB)
Savvopoulou, Vasiliki; Vlahos, Lampros; Moulopoulos, Lia Angela [University of Athens, Areteion Hospital, Department of Radiology, Medical School, Athens (Greece); Maris, Thomas G. [University of Crete, Deparment of Medical Physics, Faculty of Medicine, Heraklion (Greece)
2008-09-15
To investigate the influence of age, sex and spinal level on perfusion parameters of normal lumbar bone marrow with dynamic contrast-enhanced MRI (DCE MRI). Sixty-seven subjects referred for evaluation of low back pain or sciatica underwent DCE MRI of the lumbar spine. After subtraction of dynamic images, a region of interest (ROI) was placed on each lumbar vertebral body of all subjects, and time intensity curves were generated. Consequently, perfusion parameters were calculated. Statistical analysis was performed to search for perfusion differences among lumbar vertebrae and in relation to age and sex. Upper (L1, L2) and lower (L3, L4, L5) vertebrae showed significant differences in perfusion parameters (p<0.05). Vertebrae of subjects younger than 50 years showed significantly higher perfusion compared to vertebrae of older ones (p<0.05). Vertebrae of females demonstrated significantly increased perfusion compared to those of males of corresponding age (p<0.05). All perfusion parameters, except for washout (WOUT), showed a mild linear correlation with age. Time to maximum slope (TMSP) and time to peak (TTPK) showed the same correlation with sex (0.22
Hansen, D Flemming; Westler, William M; Kunze, Micha B A; Markley, John L; Weinhold, Frank; Led, Jens J
2012-03-14
A natural bond orbital (NBO) analysis of unpaired electron spin density in metalloproteins is presented, which allows a fast and robust calculation of paramagnetic NMR parameters. Approximately 90% of the unpaired electron spin density occupies metal-ligand NBOs, allowing the majority of the density to be modeled by only a few NBOs that reflect the chemical bonding environment. We show that the paramagnetic relaxation rate of protons can be calculated accurately using only the metal-ligand NBOs and that these rates are in good agreement with corresponding rates measured experimentally. This holds, in particular, for protons of ligand residues where the point-dipole approximation breaks down. To describe the paramagnetic relaxation of heavy nuclei, also the electron spin density in the local orbitals must be taken into account. Geometric distance restraints for (15)N can be derived from the paramagnetic relaxation enhancement and the Fermi contact shift when local NBOs are included in the analysis. Thus, the NBO approach allows us to include experimental paramagnetic NMR parameters of (15)N nuclei as restraints in a structure optimization protocol. We performed a molecular dynamics simulation and structure determination of oxidized rubredoxin using the experimentally obtained paramagnetic NMR parameters of (15)N. The corresponding structures obtained are in good agreement with the crystal structure of rubredoxin. Thus, the NBO approach allows an accurate description of the geometric structure and the dynamics of metalloproteins, when NMR parameters are available of nuclei in the immediate vicinity of the metal-site.
Noroozi, S.; Rahman, A. G. A.; Dupac, M.; Vinney, J. E.
Current methods of evaluating the performance of Energy Storing and Returning (ESR) prosthesis are subjective and rely on VO2 consumption. Current prosthetic feet are designed for specific applications and the majority are designed for walking and moderate running. These mechanical feet have fixed mechanical and dynamic characteristics. They have to be selected to meet the requirement of the task and any use outside the domain of the task can result in extreme/severe lack of gait symmetry and loss of energy. Poor gait symmetry results is excess consumption of energy, back pain or fatigue. To investigate if a multipurpose foot can be designed to passively adapt to the walking or running condition one must first understand the different dynamics that are involved and are required from the task specific foot. Static tests have shown these feet to have non-linear stiffness, making the prediction of their dynamic response difficult. The most reliable method to test for dynamic characteristics is drop and modal testing. A method approach has been developed as part of this research to test and compare the dynamic characteristics of three different types of foot (natural frequency, mode shapes and damping). This is needed to explore the differences in the responses of these feet that allow one to be used for walking, one to be used for running and one to be used for sprinting with ease.
Nuclear structure with unitarily transformed two-body plus phenomenological three-body interactions
Energy Technology Data Exchange (ETDEWEB)
Guenther, Anneke
2011-02-02
calculate the {sup 4}He ground-state energy. As they are of direct interest for nuclear astrophysics collective excitation modes, namely giant resonances, are investigated in the framework of the Random Phase Approximation. Including the full three-body interaction would be very time-demanding. Therefore, a density-dependent two-body interaction is used instead. This simple interaction leads to a significant improvement in the description of the isovector dipole and isoscalar quadrupole resonances while the isoscalar monopole resonances remain in good agreement with experimental data compared to the results obtained with pure unitarily transformed two-body interactions. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Andersen, Erlend K.F. [Department of Medical Physics, Oslo University Hospital, Oslo (Norway); Hole, Knut Hakon; Lund, Kjersti V. [Department of Radiology, Oslo University Hospital, Oslo (Norway); Sundfor, Kolbein [Department of Gynaecological Oncology, Oslo University Hospital, Oslo (Norway); Kristensen, Gunnar B. [Department of Gynaecological Oncology, Oslo University Hospital, Oslo (Norway); Institute for Medical Informatics, Oslo University Hospital, Oslo (Norway); Lyng, Heidi [Department of Radiation Biology, Oslo University Hospital, Oslo (Norway); Malinen, Eirik, E-mail: eirik.malinen@fys.uio.no [Department of Medical Physics, Oslo University Hospital, Oslo (Norway); Department of Physics, University of Oslo, Oslo (Norway)
2012-03-01
Purpose: To systematically screen the tumor contrast enhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile-time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile-time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile-time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile-time interval of nRSI was associated with progression-free survival. Conclusions: The percentile-time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.
Cai, Xiuhong; Li, Xiang; Qi, Hong; Wei, Fang; Chen, Jianyong; Shuai, Jianwei
2016-10-01
The gating properties of the inositol 1, 4, 5-trisphosphate (IP3) receptor (IP3R) are determined by the binding and unbinding capability of Ca2+ ions and IP3 messengers. With the patch clamp experiments, the stationary properties have been discussed for Xenopus oocyte type-1 IP3R (Oo-IP3R1), type-3 IP3R (Oo-IP3R3) and Spodoptera frugiperda IP3R (Sf-IP3R). In this paper, in order to provide insights about the relation between the observed gating characteristics and the gating parameters in different IP3Rs, we apply the immune algorithm to fit the parameters of a modified DeYoung-Keizer model. By comparing the fitting parameter distributions of three IP3Rs, we suggest that the three types of IP3Rs have the similar open sensitivity in responding to IP3. The Oo-IP3R3 channel is easy to open in responding to low Ca2+ concentration, while Sf-IP3R channel is easily inhibited in responding to high Ca2+ concentration. We also show that the IP3 binding rate is not a sensitive parameter for stationary gating dynamics for three IP3Rs, but the inhibitory Ca2+ binding/unbinding rates are sensitive parameters for gating dynamics for both Oo-IP3R1 and Oo-IP3R3 channels. Such differences may be important in generating the spatially and temporally complex Ca2+ oscillations in cells. Our study also demonstrates that the immune algorithm can be applied for model parameter searching in biological systems.
Directory of Open Access Journals (Sweden)
E. V. Vysotskaya
2016-03-01
Full Text Available The "Introduction" describes topicality and importance of revealing the soil cover's disruption for a wide range of fields. It was shown that spectral brightness and colorimetric parameters of ground vegetation can be used for this task. However, a traditional scheme of data processing for remote sensing requires a long-term observations and can not always be applied, if quick decision-making is necessary or there is lack of information. Such cases require the use of special methods, one of which is a dynamic model developed with authors' participation based on the following basic relationships: (+,- (-, - (+, 0, (-, 0 (0,0. The section "Brief description of a dynamic model" describes the basic principles of dynamic systems used to solve the problem. Using above-mentioned relationships, the dynamics of a system consisting of several components is constructed and its main properties are listed. The main feature of this model is that the identification of structure and parameters of the dynamic system does not required sequential order of observations (as for models based on time series. This feature of the model enables for identifying the system's parameters of dynamics of the natural system to use information from a single picture taken from the spacecraft rather than long-term observations. The section "Materials and Methods" describes specific colorimetric parameters used to analyze the vegetation cover. The section "Obtained results" contains an example of the model's application to a satellite image for detecting the differences in two sites of a field with vegetation. One site is a recultivated area near the liquidated gas-oil well, another site is non-recultivated area at a considerable distance from the well (500-1000 m. The simulation results are described by eight signed graphs (4 graphs for each sites, whose structure allows to identify the system differences between the two cases. The section "Conclusions" summarizes the results of
Fodor, Z; Sexty, D; Török, C
2015-01-01
We study lattice QCD at non-vanishing chemical potential using the complex Langevin equation. We compare the results with multi-parameter reweighting both from $\\mu=0$ and phase quenched ensembles. We find a good agreement for lattice spacings below $\\approx$0.15 fm. On coarser lattices the complex Langevin approach breaks down. Four flavors of staggered fermions are used on $N_t=4, 6$ and 8 lattices. For one ensemble we also use two flavors to investigate the effects of rooting.
Expected oscillation parameters for red giants from dynamical masses and radii
Directory of Open Access Journals (Sweden)
Themeßl Nathalie
2017-01-01
Full Text Available Stellar masses and radii of stars with stochastic (solar-like oscillations can be derived using asteroseismic scaling relations. Here, we predict the asteroseismic observables using the dynamical masses and radii from red-giants in eclipsing binary systems. We show that the predicted frequency of maximum oscillation power (νmax is generally lower than the observed one, while the predicted large frequency separation (Δν is in most cases larger than the observed value. This shows that both the scaling relations for Δν and νmax used with solar references contribute to the observed differences between dynamical and asteroseismically determined masses and radii.
Effects of acoustic parameters on bubble cloud dynamics in ultrasound tissue erosion (histotripsy).
Xu, Zhen; Hall, Timothy L; Fowlkes, J Brian; Cain, Charles A
2007-07-01
High intensity pulsed ultrasound can produce significant mechanical tissue fractionation with sharp boundaries ("histotripsy"). At a tissue-fluid interface, histotripsy produces clearly demarcated tissue erosion and the erosion efficiency depends on pulse parameters. Acoustic cavitation is believed to be the primary mechanism for the histotripsy process. To investigate the physical basis of the dependence of tissue erosion on pulse parameters, an optical method was used to monitor the effects of pulse parameters on the cavitating bubble cloud generated by histotripsy pulses at a tissue-water interface. The pulse parameters studied include pulse duration, peak rarefactional pressure, and pulse repetition frequency (PRF). Results show that the duration of growth and collapse (collapse cycle) of the bubble cloud increased with increasing pulse duration, peak rarefactional pressure, and PRF when the next pulse arrived after the collapse of the previous bubble cloud. When the PRF was too high such that the next pulse arrived before the collapse of the previous bubble cloud, only a portion of histotripsy pulses could effectively create and collapse the bubble cloud. The collapse cycle of the bubble cloud also increased with increasing gas concentration. These results may explain previous in vitro results on effects of pulse parameters on tissue erosion.
Weinert, Wagner Rodrigo; Lopes, Heitor Silvério
2010-01-01
The simulation of the dynamics of a cellular systems based on cellular automata (CA) can be computationally expensive. This is particularly true when such simulation is part of a procedure of rule induction to find suitable transition rules for the CA. Several efforts have been described in the literature to make this problem more treatable. This work presents a study about the efficiency of dynamic behavior forecasting parameters (DBFPs) used for the induction of transition rules of CA for a specific problem: the classification by the majority rule. A total of 8 DBFPs were analyzed for the 31 best-performing rules found in the literature. Some of these DBFPs were highly correlated each other, meaning they yield the same information. Also, most rules presented values of the DBFPs very close each other. An evolutionary algorithm, based on gene expression programming, was developed for finding transition rules according a given preestablished behavior. The simulation of the dynamic behavior of the CA is not used to evaluate candidate transition rules. Instead, the average values for the DBFPs were used as reference. Experiments were done using the DBFPs separately and together. In both cases, the best induced transition rules were not acceptable solutions for the desired behavior of the CA. We conclude that, although the DBFPs represent interesting aspects of the dynamic behavior of CAs, the transition rule induction process still requires the simulation of the dynamics and cannot rely only on the DBFPs.
Regularities in Many-body Systems Interacting by a Two-body Random Ensemble
Zhao, Y M; Yoshinaga, N
2003-01-01
The even-even nuclei always have zero ground state angular momenta $I$ and positive parities $\\pi$. This feature was believed to be just a consequence of the attractive short-range interactions between nucleons. However, in the presence of two-body random interactions, the predominance of $I^{\\pi}=0^+$ ground states (0 g.s.) was found to be robust both for bosons and for an even number of fermions. For simple systems, such as $d$ bosons, $sp$ bosons, $sd$ bosons, and a few fermions in single-$j$ shells for small $j$, there are a few approaches to predict and/or explain the distribution of angular momentum $I$ ground state probabilities. An empirical recipe to predict the $I$ g.s. probabilities is available for general cases, but a more fundamental understanding of the robustness of 0 g.s. dominance is still out of reach. Other interesting results are also reviewed concerning other robust phenomena of many-body systems in the presence of random interactions, such as odd-even staggering of binding energies, gen...
Smallness of tree-dominated charmless two-body baryonic B decay rates
Cheng, Hai-Yang; Chua, Chun-Khiang
2015-02-01
The long-awaited baryonic B decay B¯0→p p ¯ was recently observed by LHCb with a branching fraction of order 1 0-8. All the earlier model predictions are too large compared with experiment. In this work, we point out that for a given tree operator Oi, the contribution from its Fiertz transformed operator, an effect often missed in the literature, tends to cancel the internal W -emission amplitude induced from Oi. The wave function of low-lying baryons is symmetric in momenta and the quark flavor with the same chirality but antisymmetric in color indices. Using these symmetry properties and the chiral structure of weak interactions, we find that half of the Feynman diagrams responsible for internal W emission cancel. Since this feature holds in the charmless modes but not in the charmful ones, we advocate that the partial cancellation accounts for the smallness of the tree-dominated charmless two-body baryonic B decays. This also explains why most previous model calculations predicted too large rates as the above consideration was not taken into account. Finally, we emphasize that, contrary to the claim in the literature, the internal W -emission tree amplitude should be proportional to the Wilson coefficient c1+c2 rather than c1-c2.
Charmless Hadronic Two-body Decays of the $B_s$ Mesons
Chen, Y H; Tseng, B; Chen, Yaw-Hwang; Cheng, Hai-Yang
1999-01-01
Two-body charmless nonleptonic decays of the B_s meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients are $\\mu$ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of N_c(LL) and N_c(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Branching ratios of $B_s\\to PP,PV,VV$ decays are calculated as a function of N_c(LR) with two different considerations for N_c(LL). We find that (i) the electroweak penguin contributions account for about 85% (for N_c(LL)=2) of the decay rates of $B_s\\to \\eta\\pi,\\eta'\\pi,\\eta\\rho,\\eta'\\rho,\\phi\\pi,\\phi\\rho$, which receive contributions only from tree and electroweak penguin diagrams; a measurement of them will provide a clean determination of the electroweak penguin coefficient a_9, (ii) electroweak penguin corrections to $B_s\\to\\omega as QCD penguin effects...
On the smallness of Tree-dominated Charmless Two-body Baryonic $B$ Decay Rates
Cheng, Hai-Yang
2014-01-01
The long awaited baryonic $B$ decay $\\bar B{}^0\\to p\\bar p$ was recently observed by LHCb with a branching fraction of order $10^{-8}$. All the earlier model predictions are too large compared with experiment. In this work, we point out that for a given tree operator $O_i$, the contribution from its Fiertz transformed operator, an effect often missed in the literature, tends to cancel the internal $W$-emission amplitude induced from $O_i$. The wave function of low-lying baryons are symmetric in momenta and the quark flavor with the same chirality, but antisymmetric in color indices. Using these symmetry properties and the chiral structure of weak interactions, we find that half of the Feynman diagrams responsible for internal $W$-emission cancel. Since this feature holds in the charmless modes but not in the charmful ones, we advocate that the partial cancellation accounts for the smallness of the tree-dominated charmless two-body baryonic $B$ decays. This also explains why most previous model calculations pr...
Entropy theorems in classical mechanics, general relativity, and the gravitational two-body problem
Oltean, Marius; Spallicci, Alessandro D A M; Sopuerta, Carlos F
2016-01-01
In classical Hamiltonian theories, entropy may be understood either as a statistical property of canonical systems, or as a mechanical property, that is, as a monotonic function of the phase space along trajectories. In classical mechanics, there are theorems which have been proposed for proving the non-existence of entropy in the latter sense. We explicate, clarify and extend the proofs of these theorems to some standard matter (scalar and electromagnetic) field theories in curved spacetime, and then we show why these proofs fail in general relativity; due to properties of the gravitational Hamiltonian and phase space measures, the second law of thermodynamics holds. As a concrete application, we focus on the consequences of these results for the gravitational two-body problem, and in particular, we prove the non-compactness of the phase space of perturbed Schwarzschild-Droste spacetimes. We thus identify the lack of recurring orbits in phase space as a distinct sign of dissipation and hence entropy producti...
Quartet correlations in N = Z nuclei induced by realistic two-body interactions
Energy Technology Data Exchange (ETDEWEB)
Sambataro, M. [Istituto Nazionale di Fisica Nucleare - Sezione di Catania, Catania (Italy); Sandulescu, N. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)
2017-03-15
Two variational quartet models previously employed in a treatment of pairing forces are extended to the case of a general two-body interaction. One model approximates the nuclear states as a condensate of identical quartets with angular momentum J = 0 and isospin T = 0 while the other let these quartets to be all different from each other. With these models we investigate the role of alpha-like quartet correlations both in the ground state and in the lowest J = 0, T = 0 excited states of even-even N = Z nuclei in the sd -shell. We show that the ground-state correlations of these nuclei can be described to a good extent in terms of a condensate of alpha-like quartets. This turns out to be especially the case for the nucleus {sup 32}S for which the overlap between this condensate and the shell model wave function is found close to one. In the same nucleus, a similar overlap is found also in the case of the first excited 0{sup +} state. No clear correspondence is observed instead between the second excited states of the quartet models and the shell model eigenstates in all the cases examined. (orig.)
Reactive two-body and three-body collisions of Ba$^+$ in an ultracold Rb gas
Krükow, Artjom; Härter, Arne; Denschlag, Johannes Hecker
2016-01-01
We analyze reactive collisions of a single Ba$^+$ ion in contact with an ultracold gas of Rb atoms at mK$\\times k_{\\mathrm{B}}$ collision energies. Mapping out the Ba$^+$ loss rate dependence on the Rb atom density we can discern two-body reactive collisions from three-body ones and for the first time determine both rate coefficients which are $k_2=3.1(6)(6)\\times 10^{-13}\\textrm{cm}^{3}\\textrm{s}^{-1}$ and $k_3=1.04(4)(45)\\times 10^{-24}\\textrm{cm}^{6}\\textrm{s}^{-1}$, respectively (statistical and systematic errors in parenthesis). Thus, the measured ternary recombination dominates over binary reactions even at moderate atom densities of $n\\approx 10^{12}\\: \\textrm{cm}^{-3}$. The results for Ba$^+$ and Rb are representative for a wide range of cold ion-atom systems and can serve as a guidance for the future development of the field of hybrid atom-ion research.
Two-body and three-body contacts for identical Bosons near unitarity.
Smith, D Hudson; Braaten, Eric; Kang, Daekyoung; Platter, Lucas
2014-03-21
In a recent experiment with ultracold trapped Rb85 atoms, Makotyn et al. studied a quantum-degenerate Bose gas in the unitary limit where its scattering length is infinitely large. We show that the observed momentum distributions are compatible with a universal relation that expresses the high-momentum tail in terms of the two-body contact C2 and the three-body contact C3. We determine the contact densities for the unitary Bose gas with number density n to be C2 ≈ 20 n(4/3) and C3 ≈ 2n(5/3). We also show that the observed atom loss rate is compatible with that from 3-atom inelastic collisions, which gives a contribution proportional to C3, but the loss rate is not compatible with that from 2-atom inelastic collisions, which gives a contribution proportional to C2. We point out that the contacts C2 and C3 could be measured independently by using the virial theorem near and at unitarity, respectively.
Dynamical restriction for a growing neck due to mass parameters in a dinuclear system
Adamian, G G; Díaz-Torres, A; Scheid, W
2000-01-01
Mass parameters for collective variables of a dinuclear system and strongly deformed mononucleus are microscopically formulated with the linear response theory making use of the width of single particle states and the fluctuation-dissipation theorem. For the relative motion of the nuclei and for the degree of freedom describing the neck between the nuclei, we calculate mass parameters with basis states of the adiabatic and diabatic two-center shell model. Microscopical mass parameters are found larger than the ones obtained with the hydrodynamical model and give a strong hindrance for a melting of the dinuclear system along the internuclear distance into a compound system. Therefore, the dinuclear system lives a long time enough comparable to the reaction time for fusion by nucleon transfer. Consequences of this effect for the complete fusion process are discussed.
DEFF Research Database (Denmark)
Isaeva, Olga B.; Kuznetsov, Sergey P.; Mosekilde, Erik
2011-01-01
The paper proposes an approach to constructing feasible examples of dynamical systems with hyperbolic chaotic attractors based on the successive transfer of excitation between two pairs of self-oscillators that are alternately active. An angular variable that measures the relations of the current...
Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines: a Parameter Study
Jarquin Laguna, A.; Diepeveen, N.F.B.
2013-01-01
In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed w
Dynamic Analysis of Fluid Power Drive-trains for Variable Speed Wind Turbines: a Parameter Study
Jarquin Laguna, A.; Diepeveen, N.F.B.
2013-01-01
In the pursuit of making wind energy technology more economically attractive, the application of fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This paper presents a dynamic model of a fluid power transmission for variable speed w
Determination of Scaling Parameter and Dynamical Resonances in Complex-Rotated Hamiltonian Ⅰ: Theory
Institute of Scientific and Technical Information of China (English)
LI Heng-Mei; ZHAO Fang; YUAN Hong-Chun; ZHAO Mei-Shan
2008-01-01
In this paper we present a theoretical analysis on the determination of the scaling parameter in the complex-rotated Hamiltonian, which has served as a basis for successful applications of the rigged Hilbert space theory for resonances. Based on the complex energy eigenvalue, E(θ) = En(θ) - iF(θ)/2, as a function of the scaling parameter The condition dER(θR)/ dθ = 0 is merely a consequence of the Virial theorem and θⅠ = θR is not a necessary condition for a resonance state. We also provide a harmonic approximation formalism for resonances in scattering over a potential barrier.
Parameter as a Switch Between Dynamical States of a Network in Population Decoding.
Yu, Jiali; Mao, Hua; Yi, Zhang
2017-04-01
Population coding is a method to represent stimuli using the collective activities of a number of neurons. Nevertheless, it is difficult to extract information from these population codes with the noise inherent in neuronal responses. Moreover, it is a challenge to identify the right parameter of the decoding model, which plays a key role for convergence. To address the problem, a population decoding model is proposed for parameter selection. Our method successfully identified the key conditions for a nonzero continuous attractor. Both the theoretical analysis and the application studies demonstrate the correctness and effectiveness of this strategy.
DYNAMIC PRODUCTION PREDICTION AND PARAMETER IDENTIFICATION FOR GAS WELL WITH VERTICAL FRACTURE
Institute of Scientific and Technical Information of China (English)
郭大立; 刘慈群; 赵金洲
2002-01-01
In order to devoid the hard work and factitious error in selecting charts while analyzing and interpreting hydraulic fracturing fracture parameters, on the basis of the nonDarcy flow factor, this paper put out the non-Darcy flow mathematical model of real gas in the formation and fracture, established the production history automatic matching model to identify fracture parameters, and offered the numerical solutions of those models, which took the variation of fracture conductivity in production process. These results offered a precise and reliable method to understand formation, analyze and evaluate the fracturing treatment quality of gas well.
Directory of Open Access Journals (Sweden)
Yong Wang
Full Text Available This paper proposes a two-stage algorithm to simultaneously estimate origin-destination (OD matrix, link choice proportion, and dispersion parameter using partial traffic counts in a congested network. A non-linear optimization model is developed which incorporates a dynamic dispersion parameter, followed by a two-stage algorithm in which Generalized Least Squares (GLS estimation and a Stochastic User Equilibrium (SUE assignment model are iteratively applied until the convergence is reached. To evaluate the performance of the algorithm, the proposed approach is implemented in a hypothetical network using input data with high error, and tested under a range of variation coefficients. The root mean squared error (RMSE of the estimated OD demand and link flows are used to evaluate the model estimation results. The results indicate that the estimated dispersion parameter theta is insensitive to the choice of variation coefficients. The proposed approach is shown to outperform two established OD estimation methods and produce parameter estimates that are close to the ground truth. In addition, the proposed approach is applied to an empirical network in Seattle, WA to validate the robustness and practicality of this methodology. In summary, this study proposes and evaluates an innovative computational approach to accurately estimate OD matrices using link-level traffic flow data, and provides useful insight for optimal parameter selection in modeling travelers' route choice behavior.
Dynamic identification of growth and survival kinetic parameters of microorganisms in foods
Inverse analysis is a mathematical method used in predictive microbiology to determine the kinetic parameters of microbial growth and survival in foods. The traditional approach in inverse analysis relies on isothermal experiments that are time-consuming and labor-intensive, and errors are accumula...
Effect of parameter mismatch on the dynamics of strongly coupled self sustained oscillators
Chakrabarty, Nilaj; Jain, Aditya; Lal, Nijil; Das Gupta, Kantimay; Parmananda, Punit
2017-01-01
In this paper, we present an experimental setup and an associated mathematical model to study the synchronization of two self-sustained, strongly coupled, mechanical oscillators (metronomes). The effects of a small detuning in the internal parameters, namely, damping and frequency, have been studied. Our experimental system is a pair of spring wound mechanical metronomes; coupled by placing them on a common base, free to move along a horizontal direction. We designed a photodiode array based non-contact, non-magnetic position detection system driven by a microcontroller to record the instantaneous angular displacement of each oscillator and the small linear displacement of the base, coupling the two. In our system, the mass of the oscillating pendula forms a significant fraction of the total mass of the system, leading to strong coupling of the oscillators. We modified the internal mechanism of the spring-wound "clockwork" slightly, such that the natural frequency and the internal damping could be independently tuned. Stable synchronized and anti-synchronized states were observed as the difference in the parameters was varied in the experiments. The simulation results showed a rapid increase in the phase difference between the two oscillators beyond a certain threshold of parameter mismatch. Our simple model of the escapement mechanism did not reproduce a complete 180° out of phase state. However, the numerical simulations show that increased mismatch in parameters leads to a synchronized state with a large phase difference.
S and T Parameters from a Light Nonstandard Higgs versus Near Conformal Dynamics
DEFF Research Database (Denmark)
Foadi, Roshan; Sannino, Francesco
2013-01-01
We determine the contribution to the $S$ and $T$ parameters coming from extensions of the standard model featuring a light nonstandard-like Higgs particle. We neatly separate, using the Landau gauge, the contribution from the purely nonstandard Higgs sector, from the one due to the interplay...
Directory of Open Access Journals (Sweden)
P. A. Ermolaev
2014-03-01
Full Text Available Data processing in the interferometer systems requires high-resolution and high-speed algorithms. Recurrence algorithms based on parametric representation of signals execute consequent processing of signal samples. In some cases recurrence algorithms make it possible to increase speed and quality of data processing as compared with classic processing methods. Dependence of the measured interferometer signal on parameters of its model and stochastic nature of noise formation in the system is, in general, nonlinear. The usage of nonlinear stochastic filtering algorithms is expedient for such signals processing. Extended Kalman filter with linearization of state and output equations by the first vector parameters derivatives is an example of these algorithms. To decrease approximation error of this method the second order extended Kalman filtering is suggested with additionally usage of the second vector parameters derivatives of model equations. Examples of algorithm implementation with the different sets of estimated parameters are described. The proposed algorithm gives the possibility to increase the quality of data processing in interferometer systems in which signals are forming according to considered models. Obtained standard deviation of estimated amplitude envelope does not exceed 4% of the maximum. It is shown that signal-to-noise ratio of reconstructed signal is increased by 60%.
Smith, Jason F.; Chen, Kewei; Pillai, Ajay S.; Horwitz, Barry
2013-01-01
The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here, we explicitly define “effective connectivity” using a common set of observation and state equations that are appropriate for three connectivity methods: dynamic causal modeling (DCM), multivariate autoregressive modeling (MAR), and switching linear dynamic systems for fMRI (sLDSf). In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons. PMID:23717258
Smith, Jason F; Chen, Kewei; Pillai, Ajay S; Horwitz, Barry
2013-01-01
The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here, we explicitly define "effective connectivity" using a common set of observation and state equations that are appropriate for three connectivity methods: dynamic causal modeling (DCM), multivariate autoregressive modeling (MAR), and switching linear dynamic systems for fMRI (sLDSf). In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons.
Directory of Open Access Journals (Sweden)
Jason Fitzgerald Smith
2013-05-01
Full Text Available The number and variety of connectivity estimation methods is likely to continue to grow over the coming decade. Comparisons between methods are necessary to prune this growth to only the most accurate and robust methods. However, the nature of connectivity is elusive with different methods potentially attempting to identify different aspects of connectivity. Commonalities of connectivity definitions across methods upon which base direct comparisons can be difficult to derive. Here we explicitly define effective connectivity using a common set of observation and state equations that are appropriate for three connectivity methods: Dynamic Causal Modeling (DCM, Multivariate Autoregressive Modeling (MAR, and Switching Linear Dynamic Systems for fMRI (sLDSf. In addition while deriving this set, we show how many other popular functional and effective connectivity methods are actually simplifications of these equations. We discuss implications of these connections for the practice of using one method to simulate data for another method. After mathematically connecting the three effective connectivity methods, simulated fMRI data with varying numbers of regions and task conditions is generated from the common equation. This simulated data explicitly contains the type of the connectivity that the three models were intended to identify. Each method is applied to the simulated data sets and the accuracy of parameter identification is analyzed. All methods perform above chance levels at identifying correct connectivity parameters. The sLDSf method was superior in parameter estimation accuracy to both DCM and MAR for all types of comparisons.
Energy Technology Data Exchange (ETDEWEB)
Niekerk, Cornelis G. van; Laak, Jeroen A.W.M. van der; Kaa, Christina A.H. de [Radboud University Medical Centre, Department of Pathology, P.O. Box 9101, Nijmegen (Netherlands); Hambrock, Thomas; Huisman, Henk-Jan; Barentsz, Jelle O. [Radboud University Medical Centre, Department of Radiology, Nijmegen (Netherlands); Witjes, J.A. [Radboud University Medical Centre, Department of Urology, Nijmegen (Netherlands)
2014-10-15
To correlate pharmacokinetic parameters of 3-T dynamic contrast-enhanced (DCE-)MRI with histopathologic microvascular and lymphatic parameters in organ-confined prostate cancer. In 18 patients with unilateral peripheral zone (pT2a) tumours who underwent DCE-MRI prior to radical prostatectomy (RP), the following pharmacokinetic parameters were assessed: permeability surface area volume transfer constant (K{sup trans}), extravascular extracellular volume (Ve) and rate constant (K{sub ep}). In the RP sections blood and lymph vessels were visualised immunohistochemically and automatically examined and analysed. Parameters assessed included microvessel density (MVD), area (MVA) and perimeter (MVP) as well as lymph vessel density (LVD), area (LVA) and perimeter (LVP). A negative correlation was found between age and K{sup trans} and K{sub ep} for tumour (r = -0.60, p = 0.009; r = -0.67, p = 0.002) and normal (r = -0.54, p = 0.021; r = -0.46, p = 0.055) tissue. No correlation existed between absolute values of microvascular parameters from histopathology and DCE-MRI. In contrast, the ratio between tumour and normal tissue (correcting for individual microvascularity variations) significantly correlated between K{sub ep} and MVD (r = 0.61, p = 0.007) and MVP (r = 0.54, p = 0.022). The lymphovascular parameters showed only a correlation between LVA and K{sub ep} (r = -0.66, p = 0.003). Significant correlations between DCE-MRI and histopathologic parameters were found when correcting for interpatient variations in microvascularity. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Boylan, C J; Rowbottom, C G; Mackay, R I, E-mail: Christopher.Boylan@physics.cr.man.ac.uk [North Western Medical Physics, Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX (United Kingdom)
2011-07-07
The delivery of volumetric modulated arc therapy (VMAT) requires the simultaneous movement of the linear accelerator gantry, multi-leaf collimators and jaws while the dose rate is varied. In this study, a VMAT delivery emulator was developed to accurately predict the characteristics of a given treatment plan, incorporating realistic parameters for gantry inertia and the variation in leaf speed with respect to gravity. The emulator was used to assess the impact of dynamic machine parameters on the delivery efficiency, using a set of prostate and head and neck VMAT plans. Initially, assuming a VMAT system with fixed dose rate bins, the allowable leaf and jaw speeds were increased and a significant improvement in treatment time and average dose rate was observed. The software was then adapted to simulate a VMAT system with continuously varying dose rate, and the increase in delivery efficiency was quantified, along with the impact of an increased leaf and jaw speed. Finally, a set of optimal dynamic machine parameters was derived assuming an idealized scenario in which the treatment is delivered in a single arc at constant maximum gantry speed.
Energy Technology Data Exchange (ETDEWEB)
Tsekhnov, A.N.; Nissenbaum, I.A.
1979-01-01
Characteristics are presented for the working regime of a synchronous motor in the drive of a drilling winch and the noncorrespondence of dynamic stability and the coefficient of use of the motor power to its operating conditions is indicated. An analysis is made of the change in nominal values of current and power, coefficient of overload, working angle and angular characteristics of the synchronous motor on the salient-pole coefficient. It was established that decrease in the salient-pole coefficient will permit a creation of a motor of lower nominal power and overall dimensions with an improvement in dynamic and static stability in the winch drive with conservation of electrical-engineering materials in production and electricity in operation.
Directory of Open Access Journals (Sweden)
Sornek Krzysztof
2016-01-01
Full Text Available The proper design of renewable energy based systems is really important to provide their efficient and safe operation. The aim of this paper is to compare the results obtained during traditional static calculations, with the results of dynamic simulations. For this reason, simulations of solar water heating (SWH system, designed for a typical residential building, were conducted in the TRNSYS (Transient System Simulation Tool. Carried out calculations allowed to determine the heat generation in the discussed system as well as to estimate the efficiency of considered installation. Obtained results were compared with the results from other available tool based on the static calculations. It may be concluded, that using dynamic simulations at the designing stage of renewable energy based systems may help to avoid many exploitation problems (including low efficiency, overheating etc. and allows to provide safe exploitation of such installations.
Nonlocality in many-body quantum systems detected with two-body correlators
Energy Technology Data Exchange (ETDEWEB)
Tura, J., E-mail: jordi.tura@icfo.es [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Augusiak, R.; Sainz, A.B. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Lücke, B.; Klempt, C. [Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover (Germany); Lewenstein, M.; Acín, A. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); ICREA—Institució Catalana de Recerca i Estudis Avançats, Lluis Campanys 3, 08010 Barcelona (Spain)
2015-11-15
Contemporary understanding of correlations in quantum many-body systems and in quantum phase transitions is based to a large extent on the recent intensive studies of entanglement in many-body systems. In contrast, much less is known about the role of quantum nonlocality in these systems, mostly because the available multipartite Bell inequalities involve high-order correlations among many particles, which are hard to access theoretically, and even harder experimentally. Standard, “theorist- and experimentalist-friendly” many-body observables involve correlations among only few (one, two, rarely three...) particles. Typically, there is no multipartite Bell inequality for this scenario based on such low-order correlations. Recently, however, we have succeeded in constructing multipartite Bell inequalities that involve two- and one-body correlations only, and showed how they revealed the nonlocality in many-body systems relevant for nuclear and atomic physics [Tura et al., Science 344 (2014) 1256]. With the present contribution we continue our work on this problem. On the one hand, we present a detailed derivation of the above Bell inequalities, pertaining to permutation symmetry among the involved parties. On the other hand, we present a couple of new results concerning such Bell inequalities. First, we characterize their tightness. We then discuss maximal quantum violations of these inequalities in the general case, and their scaling with the number of parties. Moreover, we provide new classes of two-body Bell inequalities which reveal nonlocality of the Dicke states—ground states of physically relevant and experimentally realizable Hamiltonians. Finally, we shortly discuss various scenarios for nonlocality detection in mesoscopic systems of trapped ions or atoms, and by atoms trapped in the vicinity of designed nanostructures.
Directory of Open Access Journals (Sweden)
Francisco José Estevez
2017-06-01
Full Text Available The present work analyses the wireless sensor network protocol (DARP and the impact of different configuration parameter sets on its performance. Different scenarios have been considered, in order to gain a better understanding of the influence of the configuration on network protocols. The developed statistical analysis is based on the method known as Analysis of Variance (ANOVA, which focuses on the effect of the configuration on the performance of DARP. Three main dependent variables were considered: number of control messages sent during the set-up time, energy consumption and convergence time. A total of 20,413 simulations were carried out to ensure greater robustness in the statistical conclusions. The main goal of this work is to discover the most critical configuration parameters for the protocol, with a view to potential applications in Smart City type scenarios.
DEFF Research Database (Denmark)
Bangsø Nielsen, Henrik
H. The experiments were carried out in lab-scale thermophilic continuously stirred tank reactors (CSTR) treating livestock waste. The imbalances included inhibition by long chain fatty acids (LCFA), inhibition by ammonia, organic overloading with proteins and organic overloading with industrial waste, i.e. meat...... out on the basis of the methane production or on the basis of fluctuations in the concentration of propionate. The experiment confirmed that propionate is a useful parameter for (1) indication of process imbalances and (2) for regulation and optimization of the anaerobic digestion process in CSTRs....... In order to gain a better insight in the activity of the propionate degraders under different operational conditions the kinetic parameters of propionate degradation by biomass from 10 CSTRs differing in temperature, hydraulic retention time (HRT) and substrates were estimated in batch substrate...
Institute of Scientific and Technical Information of China (English)
Long Wang; Jiachun Li; Jifu Zhou
2009-01-01
The calculation of settling speed of coarse parti-cles is firstly addressed, with accelerated Stokesian dynamics without adjustable parameters, in which far field force act-ing on the particle instead of particle velocity is chosen as dependent variables to consider inter-particle hydrodynamic interactions. The sedimentation of a simple cubic array of spherical particles is simulated and compared to the results available to verify and validate the numerical code and computational scheme. The improved method keeps the same computational cost of the order O(Nlog N) as usual accelerated Stokesian dynamics does. Then, more realistic random suspension sedimentation is investigated with the help of Mont Carlo method. The computational results agree well with experimental fitting. Finally, the sedimentation of finer cohesive particle, which is often observed in estuary environment, is presented as a further application in coastal engineering.
Dichev, D.; Koev, H.; Bakalova, T.; Louda, P.
2014-08-01
The present paper considers a new model for the formation of the dynamic error inertial component. It is very effective in the analysis and synthesis of measuring instruments positioned on moving objects and measuring their movement parameters. The block diagram developed within this paper is used as a basis for defining the mathematical model. The block diagram is based on the set-theoretic description of the measuring system, its input and output quantities and the process of dynamic error formation. The model reflects the specific nature of the formation of the dynamic error inertial component. In addition, the model submits to the logical interrelation and sequence of the physical processes that form it. The effectiveness, usefulness and advantages of the model proposed are rooted in the wide range of possibilities it provides in relation to the analysis and synthesis of those measuring instruments, the formulation of algorithms and optimization criteria, as well as the development of new intelligent measuring systems with improved accuracy characteristics in dynamic mode.
Directory of Open Access Journals (Sweden)
V.A. Bazhenov
2014-12-01
Full Text Available Authors in their works study vibroimpact system dynamic behaviour by numerical parametric continuation technique combined with shooting and Newton-Raphson’s methods. The technique is adapted to two-mass two-degree-of-freedom vibroimpact system under periodic excitation. Impact is simulated by nonlinear contact interaction force based on Hertz’s contact theory. Stability or instability of obtained periodic solutions is determined by monodromy matrix eigenvalues (multipliers based on Floquet’s theory. In the present paper we describe the state of problem of parameter continuation method using for nonlinear tasks solution. Also we give the short survey of numerous contemporary literature in English and Russian about parameter continuation method application for nonlinear problems. This method is applied for vibroimpact problem solving more rarely because of the difficulties connected with repeated impacts.
Looms, M. C.; Jensen, K. H.; Wildenschild, D.; Christensen, B. S.; Gudbjerg, J.
2003-12-01
Both dynamic (one-step) and semi-static (syringe pump) outflow experiments were carried out in the lab to test whether the resulting retention characteristics differed according to experiment type. Three sands of varying uniformity and coarseness were packed in a cylindrical sample holder. Compressed air was used to control the air phase pressure, while water was allowed to drain at atmospheric pressure from the outlet at the bottom of the sample. During the outflow experiments the capillary pressure was measured within the sample holder using a tensiometer connected to a pressure transducer. A medical CT-scanner was used to visualize and quantify the outflow patterns within the sand matrix during selected outflow experiments. Positive vertical shifts in capillary pressure during dynamic experiments were found in all three sand types at saturations close to porosity. The size and shape of the shifts corresponded with the dynamic effects found in previous work on the topic. Furthermore, the shifts were slightly greater in the coarsest and most uniform sand type. Numerical simulations of the one-step experiments using HYDRUS1D and T2VOC showed, however, that one of the basic assumptions when calculating the capillary pressure was most likely violated. The air phase could not be considered to be continuous at all times, and assuming this to be the case would result in positive shifts of the retention curves when running T2VOC. The results of using the CT-scanner showed the importance of achieving a homogeneous packing, since the investigated sand packing turned out to have an area at the edge of the sample holder with a higher porosity. This caused the edge to control the initial drainage. Therefore, the data collected at high saturations could not be expected to adequately describe the hydraulic properties of the inner sand. We also found that the time at which the inner sand commenced drainage coincided with a jump in capillary pressure for the resulting measured
Ovcharenko, A.; Sokolov, V.; Loh, C.-H.; Wen, K.-L.
The method for evaluation of seismic and geodynamic hazard, which is based on the models of dynamic deformation of the Earth' crust, is proposed. The 4D-model of deformation (x, y, z, t - geographic coordinates, depth, time) is constructed on the basis the geophysical data: Global Positioning System (GPS) network, Persistent Sea Water Level (PSWL) monitoring and seismic catalogues. It is possible to utilize also other indirect geophysical data that reflect the dynamic process of the Earth' crust deformation. The process of deformation is considered in the form of interaction of slow-propagating waves of deformation, the moving velocities of which vary from 0.05 per year up to 300 km per year, and the effective widths of which are about sev- eral tens of kilometers. The main goal of the modeling is to determine characteristics of these waves (fronts) of dynamic deformation on the basis of observed data. The possible seismic events (earthquakes), on the one hand, could be revealed by analysis of distribution of deformation inside the Earth' crust. The recent 1999 Chi-Chi, Tai- wan, earthquake (M=7.6) is used as an example. On the other hand, it is proposed to consider seismic events as the peculiar points of the field of dynamic deformation - the moments of interaction of four and more fronts of deformation. The 5D-model (ge- ographic coordinates, depth, time, magnitude), which describes the seismic process statistically, is used for evaluation of the earthquakes magnitude. The 4D/5D-models are applied jointly for compilation of theoretical seismic catalogue for the nearest tens and hundreds years (future and past) that, in turn, is used for purposes of seismic zona- tion and hazard assessment. The process and results of the modeling are described for the case of Taiwan region. When comparing the real and modeled seismic catalogues, it has been shown that the standard errors of determination of the earthquake param- eters do not exceed 5-10 km by coordinates, 0
A Consistent Dynamic Finite Element Formulation For a Pipe Using Euler Parameters
Directory of Open Access Journals (Sweden)
Ara Arabyan
1998-01-01
Full Text Available A pipe element developed earlier for the analysis of combined large bending and torsional deformations of blood vessels under static loading is extended to model behavior in the presence of large rotations and time-varying external forces. As in the case of the earlier element, the enhanced element supports ovalization and warping of its cross-section. The enhancements presented in this paper are comprised of a mass matrix and gyroscopic effects resulting from fast rotation rates and large deformations. The effectiveness of the element is demonstrated by two examples, which simulate the three-dimensional behavior of a highly flexible pipe under dynamic loading conditions.
Directory of Open Access Journals (Sweden)
Nicolette Meshkat
Full Text Available Parameter identifiability problems can plague biomodelers when they reach the quantification stage of development, even for relatively simple models. Structural identifiability (SI is the primary question, usually understood as knowing which of P unknown biomodel parameters p1,…, pi,…, pP are-and which are not-quantifiable in principle from particular input-output (I-O biodata. It is not widely appreciated that the same database also can provide quantitative information about the structurally unidentifiable (not quantifiable subset, in the form of explicit algebraic relationships among unidentifiable pi. Importantly, this is a first step toward finding what else is needed to quantify particular unidentifiable parameters of interest from new I-O experiments. We further develop, implement and exemplify novel algorithms that address and solve the SI problem for a practical class of ordinary differential equation (ODE systems biology models, as a user-friendly and universally-accessible web application (app-COMBOS. Users provide the structural ODE and output measurement models in one of two standard forms to a remote server via their web browser. COMBOS provides a list of uniquely and non-uniquely SI model parameters, and-importantly-the combinations of parameters not individually SI. If non-uniquely SI, it also provides the maximum number of different solutions, with important practical implications. The behind-the-scenes symbolic differential algebra algorithms are based on computing Gröbner bases of model attributes established after some algebraic transformations, using the computer-algebra system Maxima. COMBOS was developed for facile instructional and research use as well as modeling. We use it in the classroom to illustrate SI analysis; and have simplified complex models of tumor suppressor p53 and hormone regulation, based on explicit computation of parameter combinations. It's illustrated and validated here for models of moderate
Meshkat, Nicolette; Kuo, Christine Er-zhen; DiStefano, Joseph
2014-01-01
Parameter identifiability problems can plague biomodelers when they reach the quantification stage of development, even for relatively simple models. Structural identifiability (SI) is the primary question, usually understood as knowing which of P unknown biomodel parameters p1,…, pi,…, pP are-and which are not-quantifiable in principle from particular input-output (I-O) biodata. It is not widely appreciated that the same database also can provide quantitative information about the structurally unidentifiable (not quantifiable) subset, in the form of explicit algebraic relationships among unidentifiable pi. Importantly, this is a first step toward finding what else is needed to quantify particular unidentifiable parameters of interest from new I-O experiments. We further develop, implement and exemplify novel algorithms that address and solve the SI problem for a practical class of ordinary differential equation (ODE) systems biology models, as a user-friendly and universally-accessible web application (app)-COMBOS. Users provide the structural ODE and output measurement models in one of two standard forms to a remote server via their web browser. COMBOS provides a list of uniquely and non-uniquely SI model parameters, and-importantly-the combinations of parameters not individually SI. If non-uniquely SI, it also provides the maximum number of different solutions, with important practical implications. The behind-the-scenes symbolic differential algebra algorithms are based on computing Gröbner bases of model attributes established after some algebraic transformations, using the computer-algebra system Maxima. COMBOS was developed for facile instructional and research use as well as modeling. We use it in the classroom to illustrate SI analysis; and have simplified complex models of tumor suppressor p53 and hormone regulation, based on explicit computation of parameter combinations. It's illustrated and validated here for models of moderate complexity, with
Salluzzi, M.; Frayne, R.; Smith, M. R.
2006-01-01
Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies. Preliminary results associated with this paper were presented at ISMRM 12th Scientific Meeting and Exhibition, Kyoto, Japan, 2004.
Ma, Wanling; Li, Na; Zhao, Weiwei; Ren, Jing; Wei, Mengqi; Yang, Yong; Wang, Yingmei; Fu, Xin; Zhang, Zhuoli; Larson, Andrew C; Huan, Yi
2016-01-01
To clarify diffusion and perfusion abnormalities and evaluate correlation between apparent diffusion coefficient (ADC), MR perfusion and histopathologic parameters of pancreatic cancer (PC). Eighteen patients with PC underwent diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Parameters of DCE-MRI and ADC of cancer and non-cancerous tissue were compared. Correlation between the rate constant that represents transfer of contrast agent from the arterial blood into the extravascular extracellular space (K, volume of the extravascular extracellular space per unit volume of tissue (Ve), and ADC of PC and histopathologic parameters were analyzed. The rate constant that represents transfer of contrast agent from the extravascular extracellular space into blood plasma, K, tissue volume fraction occupied by vascular space, and ADC of PC were significantly lower than nontumoral pancreases. Ve of PC was significantly higher than that of nontumoral pancreas. Apparent diffusion coefficient and K values of PC were negatively correlated to fibrosis content and fibroblast activation protein staining score. Fibrosis content was positively correlated to Ve. Apparent diffusion coefficient values and parameters of DCE-MRI can differentiate PC from nontumoral pancreases. There are correlations between ADC, K, Ve, and fibrosis content of PC. Fibroblast activation protein staining score of PC is negatively correlated to ADC and K. Apparent diffusion coefficient, K, and Ve may be feasible to predict prognosis of PC.
Salluzzi, M; Frayne, R; Smith, M R
2006-01-21
Several groups have modified the standard singular value decomposition (SVD) algorithm to produce delay-insensitive cerebral blood flow (CBF) estimates from dynamic susceptibility contrast (DSC) perfusion studies. However, new dependences of CBF estimates on bolus arrival times and slice position in multi-slice studies have been recently recognized. These conflicting findings can be reconciled by accounting for several experimental and algorithmic factors. Using simulation and clinical studies, the non-simultaneous measurement of arterial and tissue concentration curves (relative slice position) in a multi-slice study is shown to affect time-related perfusion parameters, e.g. arterial-tissue-delay measurements. However, the current clinical impact of relative slice position on amplitude-related perfusion parameters, e.g. CBF, can be expected to be small unless any of the following conditions are present individually or in combination: (a) high concentration curve signal-to-noise ratios, (b) small tissue mean transit times, (c) narrow arterial input functions or (d) low temporal resolution of the DSC image sequence. Recent improvements in magnetic resonance (MR) technology can easily be expected to lead to scenarios where these effects become increasingly important sources of inaccuracy for all perfusion parameter estimates. We show that using Fourier interpolated (high temporal resolution) residue functions reduces the systematic error of the perfusion parameters obtained from multi-slice studies.
Mansell, Erin J; Docherty, Paul D; Fisk, Liam M; Chase, J Geoffrey
2015-08-01
Some individuals with type 1 diabetes mellitus find self-managed glycaemic control difficult due to the confounding influence of secondary effects. Stress and sleep deprivation temporarily lower insulin sensitivity (SI), often resulting in hyperglycaemia, while aerobic exercise depletes glucose, leading to hypoglycaemia if treatment is unchanged. This study tests the estimation of these factors and circadian rhythms of SI in noisy data. Sparse, irregular and noisy virtual blood glucose data, mimicking the glycaemic dynamics of an individual with type 1 diabetes, was created via adapted pharmacokinetic-pharmacodynamic models of glucose and insulin that included the impact of the secondary effects. A Gauss-Newton algorithm was used to recover the original model parameters for SI, stress, fatigue and exercise. During longer identification periods, compensation was made for drift in SI. Monte Carlo analyses were undertaken to validate the methods. The coefficient of variation (CV) in all parameters decreased as the data accumulated in proportion to the 1/n rule (R(2) > 99.9%). Relatively small biases from the original parameter values occurred (data to override the effect of measurement error. Compensation for SI drift allows viable observation of secondary effects and SI rhythms over longer time periods. Collectively, these outcomes indicate that quality results for identified parameters could be obtained during in vivo studies.
Ramteke, D. D.; Balakrishna, A.; Kumar, Vijay; Swart, H. C.
2017-02-01
Sm3+ ion doped 20 ZnOsbnd 10Li2Osbnd 10Na2Osbnd 60P2O5 glasses were prepared. The density was determined by the Archimedes method and the glasses were analyzed by using, optical absorption spectroscopy, excitation and emission luminescence studies. The Sm3+ concentration was varied between 0 and 1 mol%. The Judd-Ofelt (J-O) parameters (Ω2, Ω4, Ω6) were calculated by using the absorption data and the least square fit method. The Nephelauxetic ratio (β), bonding parameters (δ), spectroscopic quality factors, effective line width (Δλeff), radiative transition probability (A) and emission cross section (σp) were deduced by using the J-O parameters and emission spectra. The emission spectra showed the 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 &4G5/2 → 6H11/2 transitions of the Sm3+ ions in the prepared glasses. Concentration quenching behavior was also observed, which was explained by the increase number of Sm3+ ions in the glass matrix. This was confirmed by the decrease in decay times with an increase in Sm3+ concentration. The analysis of the concentration shows 0.75 mol % Sm2O3 containing glasses can possibly be used for visible laser and fiber optic amplifier applications due to the fact that it has higher emission cross section and branching ratio values.
Directory of Open Access Journals (Sweden)
SungJoong Kim, JaeHo Yu
2015-06-01
Full Text Available This study aimed to clarify the mechanical gait changes caused by achilles tendinopathy by comparing gait parameters and changes in hip, knee, and ankle moments between an experimental group (EG and a control group (CG. Twenty runners with achilles tendinopathy were included in the EG (male/female: 10/10, age: 27.00 ± 4.63, and 20 CG (male/female: 10/10, age: 27.25 ± 4.33 participants were recruited. Subjects walked a 13-m distance at their normal walking speed 5 times to obtain motion analysis and joint moment data. Gait parameter analysis showed significant differences in double-limb support (EG: 22.65 ± 4.26%, CG: 20.37 ± 4.46%, step length (EG: 0.58 ± 0.0 7m, CG: 0.64 ± 0.08 m, step width (EG: 0.16 ± 0.04 m, CG: 0.14 ± 0.05 m, stride time (EG: 1.09 ± 0.10 second, CG: 1.05 ± 0.08 second, and walking speed (EG: 1.09±0.18 m·s-1, CG: 1.23 ± 0.17 m·s-1 between the 2 groups (p < 0.05. Significant differences were found in hip joint moment for initial contact, mid-stance, terminal stance, and pre-swing phases; knee joint moment for initial contact and pre-swing phases; and ankle joint moment for pre-swing and terminal swing phases (p < 0.05. Gait parameters and hip, knee, and ankle moments were altered in runners with achilles tendinopathy. Thus, clinical features of gait changes should be understood for optimal treatment of achilles tendinopathy; further research is required in this field.
The dynamics of blood biochemical parameters in cosmonauts during long-term space flights
Markin, Andrei; Strogonova, Lubov; Balashov, Oleg; Polyakov, Valery; Tigner, Timoty
Most of the previously obtained data on cosmonauts' metabolic state concerned certain stages of the postflight period. In this connection, all conclusions, as to metabolism peculiarities during the space flight, were to a large extent probabilistic. The purpose of this work was study of metabolism characteristics in cosmonauts directly during long-term space flights. In the capillary blood samples taken from a finger, by "Reflotron IV" biochemical analyzer, "Boehringer Mannheim" GmbH, Germany, adapted to weightlessness environments, the activity of GOT, GPT, CK, gamma-GT, total and pancreatic amylase, as well as concentration of hemoglobin, glucose, total bilirubin, uric acid, urea, creatinine, total, HDL- and LDL cholesterol, triglycerides had been determined. HDL/LDL-cholesterol ratio also was computed. The crewmembers of 6 main missions to the "Mir" orbital station, a total of 17 cosmonauts, were examined. Biochemical tests were carryed out 30-60 days before lounch, and in the flights different stages between the 25-th and the 423-rd days of flights. In cosmonauts during space flight had been found tendency to increase, in compare with basal level, GOT, GPT, total amylase activity, glucose and total cholesterol concentration, and tendency to decrease of CK activity, hemoglobin, HDL-cholesterol concentration, and HDL/LDL — cholesterol ratio. Some definite trends in variations of other determined biochemical parameters had not been found. The same trends of mentioned biochemical parameters alterations observed in majority of tested cosmonauts, allows to suppose existence of connection between noted metabolic alterations with influence of space flight conditions upon cosmonaut's body. Variations of other studied blood biochemical parameters depends on, probably, pure individual causes.
Simulation of the relationship between roadway dynamic destruction and hypocenter parameters
Institute of Scientific and Technical Information of China (English)
GAO Ming-shi; DOU Lin-ming; ZHANG Nong; XIE Yao-she; ZHENG Bai-sheng
2008-01-01
Many factors can induce rock burst. Shock energy and shock distance are two key factors affecting rock burst. The 32101 roadway of the Xingcun coal mine, which has a tendency for rock burst, was used as an example. The dynamic module of Itasca's FLAC (Fast Lagrangian Analysis of Continua) 2D explicit finite-difference software was used to simulate the roadway's destruction. The vibration velocity and displacements of the rock surrounding the roadway were modeled for different shock energies and hypo-center distances. The simulation results indicate that the vibration velocity and displacement of rock surrounding the roadway have a quadratic relationship to the shock energy and a power law relationship to the distance of the hypocenter from the roadway. A dynamic view of the process was obtained from a series of "snap-shots" collected at 100 different time steps. This shows an isolat-ing "river" is first formed at the hypocenter. The region above the "river" is a low stress zone while below the "river" a high stress zone exists. This high stress zone surrounds the ribs of the roadway in a "double ear" pattern. Continuous and repeated action of the high stress in the "double ear" shaped zone destroys the roadway.
Dynamics of target-mediated drug disposition: characteristic profiles and parameter identification.
Peletier, Lambertus A; Gabrielsson, Johan
2012-10-01
In this paper we present a mathematical analysis of the basic model for target mediated drug disposition (TMDD). Assuming high affinity of ligand to target, we give a qualitative characterisation of ligand versus time graphs for different dosing regimes and derive accurate analytic approximations of different phases in the temporal behaviour of the system. These approximations are used to estimate model parameters, give analytical approximations of such quantities as area under the ligand curve and clearance. We formulate conditions under which a suitably chosen Michaelis-Menten model provides a good approximation of the full TMDD-model over a specified time interval.
DEFF Research Database (Denmark)
De Figueiredo, Daniela R.; P. S. Reboleira, Ana Sofia; Antunes, Sara C.
2006-01-01
(particularly phosphorus). Diatoms were dominant during winter months (inferior temperatures and higher nutrients availability) followed by green algae in early spring and then cyanobacteria from late spring until early autumn (less nutrient availability and higher temperatures). A massive cyanobacterial bloom...... was also detected in July 2001 and it occurred following a rapid decrease in abundance of green algae and diatoms. By considering not only the environmental parameters but also the occurrence of cyanobacterial blooms as explanatory variables in a canonical correspondence analysis, the variance explained...
Kim, SungJoong; Yu, JaeHo
2015-06-01
This study aimed to clarify the mechanical gait changes caused by achilles tendinopathy by comparing gait parameters and changes in hip, knee, and ankle moments between an experimental group (EG) and a control group (CG). Twenty runners with achilles tendinopathy were included in the EG (male/female: 10/10, age: 27.00 ± 4.63), and 20 CG (male/female: 10/10, age: 27.25 ± 4.33) participants were recruited. Subjects walked a 13-m distance at their normal walking speed 5 times to obtain motion analysis and joint moment data. Gait parameter analysis showed significant differences in double-limb support (EG: 22.65 ± 4.26%, CG: 20.37 ± 4.46%), step length (EG: 0.58 ± 0.0 7m, CG: 0.64 ± 0.08 m), step width (EG: 0.16 ± 0.04 m, CG: 0.14 ± 0.05 m), stride time (EG: 1.09 ± 0.10 second, CG: 1.05 ± 0.08 second), and walking speed (EG: 1.09±0.18 m·s(-1), CG: 1.23 ± 0.17 m·s(-1)) between the 2 groups (p phases; knee joint moment for initial contact and pre-swing phases; and ankle joint moment for pre-swing and terminal swing phases (p Gait parameters and hip, knee, and ankle moments were altered in runners with achilles tendinopathy. Thus, clinical features of gait changes should be understood for optimal treatment of achilles tendinopathy; further research is required in this field. Key pointsA reduction in gait parameters, namely, step length, stride length, and walking speed, and an increase in double-limb support occurs in runners with achilles tendinopathy.A reduction in the hip extension moment occurs during the initial contact, as well as a reduction in the knee flexion moment from the mid-stance to pre-swing phases, a continuous decrease in the knee flexion moment from the early stance phase, and a reduction in the extension moment during the terminal stance phase.A reduction in the ankle plantar flexion moment occurs from the mid-stance phase and that a reduction in the dorsiflexion moment occurs during the terminal swing phase.
Quantum hysteresis loops in microscopic system: The loop area as a dynamical parameter
Indian Academy of Sciences (India)
Chandan Kumar Mondal; S P Bhattacharyya
2001-01-01
The area enclosed by hysteresis loops in a periodically forced bistable microscopic system at zero-temperature is examined by using the time dependent Hellmann–Feynman theorem and the Fourier grid Hamiltonian recipe for solving time-dependent Schrödinger equation. Effects of non-zero temperatures are explored with reference to a symmetric double well potential. The barrier crossing or, relaxation rates are shown to correlate systematically with the area of the loop. The possible use of hysteresis loop area in designing ﬁeld parameters for optimal control is suggested.
Directory of Open Access Journals (Sweden)
R.Kaniezhil
2012-01-01
Full Text Available Cognitive radio nodes have been proposed as means to improve the spectrum utilization. It reuses the spectrum of a primary service provider under the condition that the primary service provider services are not harmfully interrupted. A cognitive radio can sense its operating environment's conditions and it is able to reconfigure itself and to communicate with other counterparts based on the status of the environment and also the requirements of the user to meet the optimal communication conditions and to keep quality of service (QoS as high as possible. The efficiency of spectrum sharing can be improved by minimizing the interference. The Utility function that captures the cooperative behavior to minimize the interference and the satisfaction to improve the throughput is investigated. The dynamic spectrum sharing algorithm can maintain the quality of service (QoS of each network while the effective spectrum utilisation is improved under a fluctuation traffic environment when the available spectrum is limited.
Estimation of dynamic energy budget parameters for the Mediterranean toothcarp (Aphanius fasciatus)
Rinaldi, A.; Montalto, V.; Lika, K.; Sanfilippo, M.; Manganaro, A.; Sarà, G.
2014-11-01
Organisms adopt different sets of physiological, behavioural and morphological trade-offs in order to cope with natural environmental fluctuations. This has consequential rebounds on ecological processes and population dynamics. Such aspects become crucial for sex-dimorphic species, where sex-specific growth variation could mirror different tactics both in energy acquisition and investment between maximum female and male body size with cascading effects on population demography. To date, different approaches have been used in order to understand the causes of individual growth rate changes in ectotherm indeterminate growers, most of which failed. Here, we propose the use of a mechanistic model based on the Dynamic Energy Budget theory (DEB; Koojiman, 2010) to investigate potential differences in energy allocation strategies adopted by individuals of different genders with the Mediterranean toothcarp Aphanius fasciatus (Valenciennes, 1821) as the model species. We collected literature and field data in order to study differences in energy allocation strategies between females and males of the same species by generating projections of possible growth performances: (1) throughout their entire life span and (2) under a context of varying functional responses. Generally, the present exercise of simulations returned different patterns of growth performance among females and males of A. fasciatus, with the former being able to better optimize energetic trade-offs under optimal environmental conditions. The present DEB parameterization exercise represents an essential step towards developing a mechanistic approach to depict metabolic strategies, which are at the base of observed sexual differences, and how such differences may impair ultimate fitness at individual and, therefore, population levels.
Joung, In Suk; Cheatham, Thomas E
2009-10-01
The dynamic and energetic properties of the alkali and halide ions were calculated using molecular dynamics (MD) and free energy simulations with various different water and ion force fields including our recently developed water-model-specific ion parameters. The properties calculated were activity coefficients, diffusion coefficients, residence times of atomic pairs, association constants, and solubility. Through calculation of these properties, we can assess the validity and range of applicability of the simple pair potential models and better understand their limitations. Due to extreme computational demands, the activity coefficients were only calculated for a subset of the models. The results qualitatively agree with experiment. Calculated diffusion coefficients and residence times between cation-anion, water-cation, and water-anion showed differences depending on the choice of water and ion force field used. The calculated solubilities of the alkali-halide salts were generally lower than the true solubility of the salts. However, for both the TIP4P(EW) and SPC/E water-model-specific ion parameters, solubility was reasonably well-reproduced. Finally, the correlations among the various properties led to the following conclusions: (1) The reliability of the ion force fields is significantly affected by the specific choice of water model. (2) Ion-ion interactions are very important to accurately simulate the properties, especially solubility. (3) The SPC/E and TIP4P(EW) water-model-specific ion force fields are preferred for simulation in high salt environments compared to the other ion force fields.
Pérez-Villegas, Angeles; Moreno, Edmundo
2015-01-01
Making use of a set of detailed potential models for normal spiral galaxies, we analyze the disk stellar orbital dynamics as the structural and dynamical parameters of the spiral arms (mass, pattern speed and pitch angle) are gradually modified. With this comprehensive study of ordered and chaotic behavior, we constructed an assemblage of orbitally supported galactic models and plausible parameters for orbitally self-consistent spiral arms models. We find that, to maintain orbital support for the spiral arms, the spiral arm mass, M$_{sp}$, must decrease with the increase of the pitch angle, $i$; if $i$ is smaller than $\\sim10\\deg$, M$_{sp}$ can be as large as $\\sim7\\%$, $\\sim6\\%$, $\\sim5\\%$ of the disk mass, for Sa, Sb, and Sc galaxies, respectively. If $i$ increases up to $\\sim25\\deg$, the maximum M$_{sp}$ is $\\sim1\\%$ of the disk mass independently in this case of morphological type. For values larger than these limits, spiral arms would likely act as transient features. Regarding the limits posed by extrem...
King, Richard P.; Udo, Mfon T.
1998-06-01
Seasonal and intersexual dynamics in parameters of the length-weight relationship of the mudskipper Periophthalmus barbarus, from Imo River estuary, Nigeria, were studied. The proportionality constant or intercept (a) was aseasonal in males, but in females it was significantly higher in the dry season (November April) than during the rains (May October) due to heightened breeding activity. The length exponent (b) depicted seasonal isometry in males. In females, isometry was evident in the dry season while a positive allometry occurred during the wet season. The sizes of the smallest and largest specimens examined did not regulate variations in the magnitudes of (a) and (b) in both sexes. The insignificant intersexual variation in the length-weight parameters suggests the possibility of using a single predictive length-weight equation for the population. However, the sexes exhibited different monthly rank-orders of (a) and (b), thus making such composite estimates unreliable for a study spanning up to a year. Values of (a) and (b) were inversely correlated in both sexes. The population dynamics implications of the results are discussed.
Directory of Open Access Journals (Sweden)
Zhenzhen Lei
2017-01-01
Full Text Available The driving pattern has an important influence on the parameter optimization of the energy management strategy (EMS for hybrid electric vehicles (HEVs. A new algorithm using simulated annealing particle swarm optimization (SA-PSO is proposed for parameter optimization of both the power system and control strategy of HEVs based on multiple driving cycles in order to realize the minimum fuel consumption without impairing the dynamic performance. Furthermore, taking the unknown of the actual driving cycle into consideration, an optimization method of the dynamic EMS based on driving pattern recognition is proposed in this paper. The simulation verifications for the optimized EMS based on multiple driving cycles and driving pattern recognition are carried out using Matlab/Simulink platform. The results show that compared with the original EMS, the former strategy reduces the fuel consumption by 4.36% and the latter one reduces the fuel consumption by 11.68%. A road test on the prototype vehicle is conducted and the effectiveness of the proposed EMS is validated by the test data.
Dynamical bifurcation in a system of coupled oscillators with slowly varying parameters
Directory of Open Access Journals (Sweden)
Igor Parasyuk
2016-08-01
Full Text Available This paper deals with a fast-slow system representing n nonlinearly coupled oscillators with slowly varying parameters. We find conditions which guarantee that all omega-limit sets near the slow surface of the system are equilibria and invariant tori of all dimensions not exceeding n, the tori of dimensions less then n being hyperbolic. We show that a typical trajectory demonstrates the following transient process: while its slow component is far from the stationary points of the slow vector field, the fast component exhibits damping oscillations; afterwards, the former component enters and stays in a small neighborhood of some stationary point, and the oscillation amplitude of the latter begins to increase; eventually the trajectory is attracted by an n-dimesional invariant torus and a multi-frequency oscillatory regime is established.
Between Pleasure and Contentment: Evolutionary Dynamics of Some Possible Parameters of Happiness.
Gao, Yue; Edelman, Shimon
2016-01-01
We offer and test a simple operationalization of hedonic and eudaimonic well-being ("happiness") as mediating variables that link outcomes to motivation. In six evolutionary agent-based simulation experiments, we compared the relative performance of agents endowed with different combinations of happiness-related traits (parameter values), under four types of environmental conditions. We found (i) that the effects of attaching more weight to longer-term than to momentary happiness and of extending the memory for past happiness are both stronger in an environment where food is scarce; (ii) that in such an environment "relative consumption," in which the agent's well-being is negatively affected by that of its neighbors, is more detrimental to survival when food is scarce; and (iii) that having a positive outlook, under which agents' longer-term happiness is increased by positive events more than it is decreased by negative ones, is generally advantageous.
Lekala, M. L.; Chakrabarti, B.; Das, T. K.; Rampho, G. J.; Sofianos, S. A.; Adam, R. M.; Haldar, S. K.
2017-01-01
We study the ground-state and the low-lying excitations of a trapped Bose gas in an isotropic harmonic potential for very small (˜ 3) to very large (˜ 10^7 ) particle numbers. We use the two-body correlated basis functions and the shape-dependent van der Waals interaction in our many-body calculations. We present an exhaustive study of the effect of inter-atomic correlations and the accuracy of the mean-field equations considering a wide range of particle numbers. We calculate the ground-state energy and the one-body density for different values of the van der Waals parameter C6 . We compare our results with those of the modified Gross-Pitaevskii results, the correlated Hartree hypernetted-chain equations (which also utilize the two-body correlated basis functions), as well as of the diffusion Monte Carlo for hard sphere interactions. We observe the effect of the attractive tail of the van der Waals potential in the calculations of the one-body density over the truly repulsive zero-range potential as used in the Gross-Pitaevskii equation and discuss the finite-size effects. We also present the low-lying collective excitations which are well described by a hydrodynamic model in the large particle limit.
Directory of Open Access Journals (Sweden)
M. S. Lyuft
2015-01-01
Full Text Available Summary. The main stop-factors in a landing were formed in the article according to the procedure of the European Bank for Reconstruction and Development by the means of questioning the leading Russian banks that finance small-scale business. It is given the description of this method, also it is identified the main weaknesses of the EBRD methodology. There is a description of the main methods of the borrowing company’s analytical balance and thereupon it is made the conclusion about the necessity of the analysis of the balance’s principal factors across time. The analysis of indicators and factors in the dynamics enables us to see trends in the development of the company, and to identify deviations in the coefficients. Either materiality or difference from normal values of these coefficients may indicate the factors of the borrowers’ misconduct, and in particular it gives evidence concerning falsification of reports provided to a bank. There are stages of information processing for falsification’s detection, excluding the interest from decision-makers about the possibility of lending in the results of a transaction. The formula that determinates the value of net profit falsification has been made on basis of dynamic parameters of the analytical balance and the connection with the administrative profit-and-loss report. Further, the article provides the second method of a determination of the net profit falsification already based on data of the parameters in dynamics namely business profitability rate. The process of calculation Payment To Income - payment to income - an indicator, in order to obtain good data on who falsify net income. Are key strengths of this method of identifying and conclusions paragraph article.
Soares, Priscilla Barbosa Ferreira; Nunes, Sarah Arantes; Franco, Sinésio Domingues; Pires, Raphael Rezende; Zanetta-Barbosa, Darceny; Soares, Carlos José
2014-01-01
The clinical performance of dental implants is strongly defined by biomechanical principles. The aim of this study was to quantify the Vicker's hardness (VHN) and elastic modulus (E) surround bone to dental implant in different regions, and to discuss the parameters of dynamic microindantion test. Ten cylindrical implants with morse taper interface (Titamax CM, Neodent; 3.5 mm diameter and 7 mm a height) were inserted in rabbit tibia. The mechanical properties were analyzed using microhardness dynamic indenter with 200 mN load and 15 s penetration time. Seven continuous indentations were made distancing 0.08 mm between each other perpendicularly to the implant-bone interface towards the external surface, at the limit of low (Lp) and high implant profile (Hp). Data were analyzed by Student's t-test (a=0.05) to compare the E and VHN values obtained on both regions. Mean and standard deviation of E (GPa) were: Lp. 16.6 ± 1.7, Hp. 17.0 ± 2.5 and VHN (N/mm2): Lp. 12.6 ± 40.8, Hp. 120.1 ± 43.7. No statistical difference was found between bone mechanical properties of high and low profile of the surround bone to implant, demonstrating that the bone characterization homogeneously is pertinent. Dynamic microindantion method proved to be highly useful in the characterization of the individual peri-implant bone tissue.
Keller, Stefanie; Valls, Maria; Hidalgo, Manuel; Quetglas, Antoni
2014-05-01
The cuttlefish Sepia officinalis constitutes an important fishery resource in the Mediterranean, where it is exploited by both the bottom trawl and small-scale fleet. However, there is currently scarce information on the Mediterranean stocks, since most studies on the population dynamics of this species have been undertaken in the northeast Atlantic. In this work we first analysed different aspects of the cuttlefish life-history from the western Mediterranean such as population structure, reproduction and the trade-offs between somatic condition and reproduction investments. Secondly, we investigated the effects of different environmental parameters (e.g. climate indices, sea surface temperature (SST), rainfall, chlorophyll-a concentration (Chla) and moon phase) on these populations, analysing several landing time series spanning the last 45 years. Our results revealed that Mediterranean cuttlefish populations exhibit strong seasonal variations owing to a reproductive migration towards coastal waters. The positive relationships between somatic and reproductive condition pointed to an income breeder strategy; this was reinforced by the percentage of empty stomachs, which was lowest just before the reproductive period peak. Despite the putative high sensitivity of cephalopod populations to external abiotic factors, our results showed that Mediterranean cuttlefish populations were not affected by most of the environmental parameters investigated. Significant effects were found for SST and a local climatic index, but no or very weak influences were evident for other parameters such as large-scale climatic phenomena (e.g. North Atlantic Oscillation, Mediterranean Oscillation) or other locally-related variables (e.g. rainfall, Chla). Our results revealed a shift in the cuttlefish population dynamics in the early 1980s, which could be related to important changes in the local hydroclimatology reported by previous authors.
Directory of Open Access Journals (Sweden)
Aysanov T. S.
2015-01-01
Full Text Available The article presents three-year data on the influence of different fertilization systems and predecessors (corn for silage and peas of winter wheat in the rotation on the dynamics of content in the 0-20 cm layer of black leached soil of mineral nitrogen, of available phosphorus, of potassium, and yield of winter wheat. The materials presented in this article indicate that, regardless of its predecessor in all phases of plant development, the under study fertilizer systems significantly increased the content of mineral nitrogen on the indicators of natural agrochemical background on 1,1-29,3 mg/kg; maximum contents was registered in the settlement system of fertilizer. After a seeded fallow predecessor the fertilizer systems significantly increased the content of available phosphorus in the soil at 1,5-16,6 mg/kg and exchangeable potassium in the 6-57 mg/kg. The maximum indices of both indicators were observed in the settlement system of fertilizer. Analyzed fertilizer systems contributed to a significant increase in wheat yield relatively to control 0,82-2,24 t/ha on a busy couple 0,74-1,6 t/ha for maize silage, 1,44-2,42 t/ha peas. Maximum productivity of winter wheat in the experiment was fixed at the fertilizer system after a busy couple, and was 6,19 t/ha
Jiang, S C; Zhang, X X
2005-12-01
A two-dimensional model was developed to model the effects of dynamic changes in the physical properties on tissue temperature and damage to simulate laser-induced interstitial thermotherapy (LITT) treatment procedures with temperature monitoring. A modified Monte Carlo method was used to simulate photon transport in the tissue in the non-uniform optical property field with the finite volume method used to solve the Pennes bioheat equation to calculate the temperature distribution and the Arrhenius equation used to predict the thermal damage extent. The laser light transport and the heat transfer as well as the damage accumulation were calculated iteratively at each time step. The influences of different laser sources, different applicator sizes, and different irradiation modes on the final damage volume were analyzed to optimize the LITT treatment. The numerical results showed that damage volume was the smallest for the 1,064-nm laser, with much larger, similar damage volumes for the 980- and 850-nm lasers at normal blood perfusion rates. The damage volume was the largest for the 1,064-nm laser with significantly smaller, similar damage volumes for the 980- and 850-nm lasers with temporally interrupted blood perfusion. The numerical results also showed that the variations in applicator sizes, laser powers, heating durations and temperature monitoring ranges significantly affected the shapes and sizes of the thermal damage zones. The shapes and sizes of the thermal damage zones can be optimized by selecting different applicator sizes, laser powers, heating duration times, temperature monitoring ranges, etc.
Wildgruber, D; Pihan, H; Ackermann, H; Erb, M; Grodd, W
2002-04-01
Appreciation of the emotional tone of verbal utterances represents an important aspect of social life. It is still unsettled, however, which brain areas mediate processing of intonational information and whether the presumed right-sided superiority depends upon acoustic properties of the speech signal. Functional magnetic resonance imaging was used to disentangle brain activation associated with (i) extraction of specific acoustic cues and (ii) detection of specific emotional states. Stimulus material comprised pairs of emotionally intonated utterances, exclusively differing either in pitch range or in the length of stressed vowels. Hemodynamic responses showed a dynamic pattern of cerebral activation including sequenced bilateral responses of various cortical and subcortical structures. Activation associated with discrimination of emotional expressiveness predominantly emerged within the right inferior parietal lobule, within the bilateral mesiofrontal cortex and--with an asymmetry toward the right hemisphere--at the level of bilateral dorsolateral frontal cortex. Lateralization did not depend upon acoustic structure or emotional valence of stimuli. These findings might prove helpful in reconciling the controversial previous clinical and experimental data. (C)2002 Elsevier Science (USA).
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Oscar Castillo
2013-01-01
Full Text Available Ant Colony Optimization (ACO is a population-based constructive meta-heuristic that exploits a form of past performance memory inspired by the foraging behaviour of real ants. The behaviour of the ACO algorithm is highly dependent on the values defined for its parameters. Adaptation and parameter control are recurring themes in the field of bio-inspired algorithms. The present paper explores a new approach to diversity control in ACO. The central idea is to avoid or slow down full convergence through the dynamic variation of certain parameters. The performance of different variants of the ACO algorithm was observed to choose one as the basis for the proposed approach. A convergence fuzzy logic controller with the objective of maintaining diversity at some level to avoid premature convergence was created. Encouraging results have been obtained on its application to the design of fuzzy controllers. In particular, the optimization of membership functions for a unicycle mobile robot trajectory control is presented with the proposed method.
Farooq, Omer; Crandall, Sara; Ratra, Bharat
2016-01-01
We compile an updated list of 28 independent measurements of the Hubble parameter $H(z)$ between redshifts $0.1 \\leq z \\leq 2.36$ and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, $z_{\\rm da}$, from these $H(z)$ data. Within the error bars, the measured $z_{\\rm da}$ are insensitive to the model used, depending only on the value assumed for the Hubble constant $H_0$. The weighted mean of our measurements is $z_{\\rm da} = 0.74 \\pm 0.06\\ (0.86 \\pm 0.04)$ for $H_0 = 68 \\pm 2.8\\ (73.8 \\pm 2.4)$ km s$^{-1}$ Mpc$^{-1}$ and should provide a reasonably model-independent estimate of this cosmological parameter. The $H(z)$ data are consistent with the standard spatially-flat $\\Lambda$CDM cosmological model but do not rule out non-flat models or dynamical dark energy models.
Farooq, Omer; Ranjeet Madiyar, Foram; Crandall, Sara; Ratra, Bharat
2017-01-01
We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 ≤ z ≤ 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration–acceleration transition, zda, from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H0. The weighted mean of our measurements is zda = 0.72 ± 0.05 (0.84 ± 0.03) for H0 = 68 ± 2.8 (73.24 ± 1.74) km s‑1 Mpc‑1 and should provide a reasonably model-independent estimate of this cosmological parameter. The H(z) data are consistent with the standard spatially flat ΛCDM cosmological model but do not rule out nonflat models or dynamical dark energy models.
Muraglia, Magali; Yagi, Masatoshi; Benkadda, Sadruddin; Peter, Beyer; Garbet, Xavier; Itoh, Sanae -I; Itoh, Kimitaka; Sen, Abhijit
2011-01-01
We present numerical simulation studies of 2D reduced MHD equations investigating the impact of the electronic \\beta parameter and of curvature effects on the nonlinear evolution of drift tearing islands. We observe a bifurcation phenomenon that leads to an amplification of the pressure energy, the generation of E \\times B poloidal flow and a nonlinear diamagnetic drift that affects the rotation of the magnetic island. These dynamical modifications arise due to quasilinear effects that generate a zonal flow at the onset point of the bifurcation. Our simulations show that the transition point is influenced by the \\beta parameter such that the pressure gradient through a curvature effect strongly stabilizes the transition. Regarding the modified rotation of the island, a model for the frequency is derived in order to study its origin and the effect of the \\beta parameter. It appears that after the transition, an E \\times B poloidal flow as well as a nonlinear diamagnetic drift are generated due to an amplificat...
Szabó, A; Mézes, M; Horn, P; Süto, Z; Bázár, Gy; Romvári, R
2005-01-01
Blood serum clinical biochemical parameters of fasted BUT Big 8 male turkeys were determined at the ages of 3 days, 4, 8, 12, 16 and 20 weeks, for a follow-up of the developmental changes of some serum metabolites, enzymes and ions. The serum protein content (total protein, albumin, globulin) increased with age, indicating also the moulting-associated metabolic changes in the age interval from the 8th to the 12th weeks. Creatinine was shown to have a peak at 3 days of age (role of muscle activity in thermogenesis), while urate concentration sensitively reflected the dietary protein amount. Serum triglycerides peaked at the time of yolk catabolism, while cholesterol was shown to indicate the moulting, as was serum malondialdehyde. Serum sodium content increased throughout the study. Alanine aminotransferase and aspartate aminotransferase activities increased along the ontogeny, while alkaline phosphatase activity decreased in parallel with the growth. Serum creatine kinase activity showed an over one-magnitude increase. General metabolic and enzymatic alterations were characteristic and applicable for the description of the ontogenetic development of a precocial (post-hatch triglyceride peak), large bodied, meat-type (lactate dehydrogenase, continuously increasing creatine kinase) bird species.
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Ales Pavlik
2015-02-01
Full Text Available In this study, effect of environmental condition changes during gazing period on energy metabolism parameters was investigated. Totally 40 Aberdeen Angus cows were selected for observation. Calving all of cows was situated into March. The feeding ration for the animals was comprised by pasture during the grazing period and corn silage, hay and granulated distiller’s grains during the winter period. At average age 9 days before calving, and subsequently 10, 81, 151, 189 and 273 days after calving, blood was sampled and analysed for glucose and NEFA (non-esterified fatty acid concentrations on KONELAB T20xt automatic analyser (Thermo Fisher Scientific, Finland and currently available commercial kits (Biovendor-Laboratorni medicina, Czech Republic. A rapid increase (p < 0.05 of glucose concentration was detected in blood plasma of cows in period before calving to 81 days post partum. Average value of glucose concentration at 273 days postpartum was significant (p < 0.05 lower comparing to day 189. The highest concentrations of NEFA in blood plasma of cows were found at 10 day postpartum. After that, during the persisted higher temperature period the NEFA concentration decreased significantly (p < 0.01 till 189 days postpartum. At the end of monitored period concentration of NEFA in blood plasma significantly decreased (p < 0.05. Changes of hot and cold season during the grazing period probably according to forage quality and had significant effects on blood plasma NEFA and glucose concentrations.
Influence of parameters on light propagation dynamics in optically induced planar waveguide arrays
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The diffraction and refraction of light beam in optical periodic structures can be determined by the photonic band-gap structures of spatial frequency.In this paper,by employing the equation governing the nonlinear light propagations in photorefractive crystals,we study the photonic band-gap structures, Bloch modes,and light transmission properties of optically induced planar waveguide arrays.The relationship between the photonic band-gap structures and the light diffraction characteristics is discussed in detail.Then the influence of the parameters of planar waveguide arrays on the band-gaps structures,Bloch modes,and linear light transmissions is analyzed.It is revealed that the linear light transmission properties of waveguide arrays are tightly related to the diffraction relationships determined by band-gap structures.And the Bloch modes corresponding to different transmission bands can be excited by different excitation schemes.Both the increases of the intensity and the period of the array writing beam will lead to the broadening of the forbidden gaps and the concentration of the energy of the Bloch modes to the high-index regions.Furthermore,the broadening of the forbidden gaps will lead to separation and transition between the Bloch modes of neighboring bands around the Bragg angle.Additionally,with the increase of the intensity of the array writing beams,the influences from light intensity will tend to be steady due to the saturation of the photorefractive effect.
Influence of parameters on light propagation dynamics in optically induced planar waveguide arrays
Institute of Scientific and Technical Information of China (English)
LIU Sheng; ZHANG Peng; XIAO FaJun; YANG DeXing; ZHAO JianLin
2009-01-01
The diffraction and refraction of light beam in optical periodic structures can be determined by the photonic band-gap structures of spatial frequency. In this paper, by employing the equation governing the nonlinear light propagations in photorefractive crystals, we study the photonic band-gap structures,Bloch modes, and light transmission properties of optically induced planar waveguide arrays. The relationship between the photonic band-gap structures and the light diffraction characteristics is discussed in detail. Then the influence of the parameters of planar waveguide arrays on the band-gaps structures, Bloch modes, and linear light transmissions is analyzed. It is revealed that the linear light transmission properties of waveguide arrays are tightly related to the diffraction relationships determined by band-gap structures. And the Bloch modes corresponding to different transmission bands can be excited by different excitation schemes. Both the increases of the intensity and the period of the array writing beam will lead to the broadening of the forbidden gaps and the concentration of the energy of the Bloch modes to the high-index regions. Furthermore, the broadening of the forbidden gaps will lead to separation and transition between the Bloch modes of neighboring bands around the Bragg angle. Additionally, with the increase of the intensity of the array writing beams, the influences from light intensity will tend to be steady due to the saturation of the photorefractive effect.
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Chao-Feng Yang
2016-01-01
Full Text Available Hydraulically damped rubber bushings (HDBs are important for vehicle noise, vibration, and harshness (NVH performance as they are able to decay the vehicle’s oscillation induced by engine and road. The dynamic stiffness and loss angle of an HDB are crucial and it is significant to investigate the relations between the design parameters with the dynamic stiffness and loss angle. Therefore, the force-deflection relation of the HDB is measured statically and the dynamic stiffness and loss angle are measured dynamically and the test data are analyzed with a view to examine how the measurement results are influenced by the design parameters (the number of the fluid tracks. Compared with the results predicted by a nonlinear lumped parameter model whose parameters are extracted by a parameter identification technique, using the model, the effect of the main rubber and the fluid track on the dynamic stiffness and the loss angle is investigated. A unified analytical model of HDB is also developed with the purpose of predicting the static and dynamic characteristics, and the predictions are shown to be well correlated with the measurement data. The good correlation suggests the validity of the model and the parameter identification implementation.
Validation of Proposed Metrics for Two-Body Abrasion Scratch Test Analysis Standards
Street, Kenneth W., Jr.; Kobrick, Ryan L.; Klaus, David M.
2013-01-01
Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two interacting materials. Knowing the abrasive nature of an environment (abrasive)/construction material is crucial to designing durable equipment for use in such surroundings. The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed Zone of Interaction (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width. The ZOI has been found to be at least twice the size of a standard width measurement; in some cases, considerably greater, indicating that at least half of the disturbed surface area would be neglected without this insight. The ZOI is used to calculate a more robust data set of volume measurements that can be used to computationally reconstruct a resultant profile for de tailed analysis. Documenting additional changes to various surface roughness par ameters also allows key material attributes of importance to ultimate design applications to be quantified, such as depth of penetration and final abraded surface roughness. Further - more, by investigating the use of custom scratch tips for specific needs, the usefulness of having an abrasion metric that can measure the displaced volume in this standardized
A covariant model of the electromagnetic current for the study of two-body scalar systems
Acero, M A; Sandoval, C E; Sanctis, Maurizio De; Sandoval, Carlos E.
2005-01-01
We present a procedure to derive a covariant electromagnetic current operator for a system made up by two scalars constituents. Using different wave functions we fitted their parameters to the experimental data of the pion form factor, obtainig great discrepancy at low momentum transfer. Introducing the Vector Meson Dominance corrective factor, we obtained a better fit to the data.
Robinson, S J Q; Robinson, Shadow J.Q.; Zamick, Larry
2002-01-01
Calculations of the spectra of various even-even nuclei in the fp shell ($^{44}$Ti, $^{46}$Ti, $^{48}$Cr, and $^{50}$Cr) are performed with two sets of two-body interaction matrix elements. The first set consists of the matrix elements of the FPD6 interaction. The second set have the same T=1 two-body matrix elements as the FPD6 interaction, but all the T=0 two-body matrix elements are set equal to zero. Despite the drastic differences between the two interactions, the spectra they yield are very similar and indeed it is difficult to say which set gives a better fit to experiment. That the results for the yrast spectra are insensitive to the presence or absence of T=0 two-body matrix elements is surprising because the only bound two nucleon system has T=0, namely the deuteron. Also there is the general folklore that T=0 matrix elements are responsible for nuclear collectivity. Electric quadrupole transition rates are also examined. It is found that the reintroduction of T=0 matrix elements leads to an enhance...
Dynamic finite element analysis of the aortic root from MRI-derived parameters.
Conti, Carlo A; Votta, Emiliano; Della Corte, Alessandro; Del Viscovo, Luca; Bancone, Ciro; Cotrufo, Maurizio; Redaelli, Alberto
2010-03-01
An understanding of aortic root biomechanics is pivotal for the optimisation of surgical procedures aimed at restoring normal root function in pathological subjects. For this purpose, computational models can provide important information, as long as they realistically capture the main anatomical and functional features of the aortic root. Here we present a novel and realistic finite element (FE) model of the physiological aortic root, which simulates its function during the entire cardiac cycle. Its geometry is based on magnetic resonance imaging (MRI) data obtained from 10 healthy subjects and accounts for the geometrical differences between the leaflet-sinus units. Morphological realism is combined with the modelling of the leaflets' non-linear and anisotropic mechanical response, in conjunction with dynamic boundary conditions. The results show that anatomical differences between leaflet-sinus units cause differences in stress and strain patterns. These are notably higher for the leaflets and smaller for the sinuses. For the maximum transvalvular pressure value, maximum principal stresses on the leaflets are equal to 759, 613 and 603 kPa on the non-coronary, right and left leaflet, respectively. For the maximum aortic pressure, average maximum principal stresses values are equal to 118, 112 and 111 kPa on the right, non-coronary and left sinus, respectively. Although liable of further improvements, the model seems to reliably reproduce the behaviour of the real aortic root: the model's leaflet stretches, leaflet coaptation lengths and commissure motions, as well as the timings of aortic leaflet closures and openings, all matched with the experimental findings reported in the literature.
Suresha, Suhas; Sujith, R. I.; Emerson, Benjamin; Lieuwen, Tim
2016-10-01
The flame or flow behavior of a turbulent reacting wake is known to be fundamentally different at high and low values of flame density ratio (ρu/ρb ), as the flow transitions from globally stable to unstable. This paper analyzes the nonlinear dynamics present in a bluff-body stabilized flame, and identifies the transition characteristics in the wake as ρu/ρb is varied over a Reynolds number (based on the bluff-body lip velocity) range of 1000-3300. Recurrence quantification analysis (RQA) of the experimentally obtained time series of the flame edge fluctuations reveals that the time series is highly aperiodic at high values of ρu/ρb and transitions to increasingly correlated or nearly periodic behavior at low values. From the RQA of the transverse velocity time series, we observe that periodicity in the flame oscillations are related to periodicity in the flow. Therefore, we hypothesize that this transition from aperiodic to nearly periodic behavior in the flame edge time series is a manifestation of the transition in the flow from globally stable, convective instability to global instability as ρu/ρb decreases. The recurrence analysis further reveals that the transition in periodicity is not a sudden shift; rather it occurs through an intermittent regime present at low and intermediate ρu/ρb . During intermittency, the flow behavior switches between aperiodic oscillations, reminiscent of a globally stable, convective instability, and periodic oscillations, reminiscent of a global instability. Analysis of the distribution of the lengths of the periodic regions in the intermittent time series and the first return map indicate the presence of type-II intermittency.
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Rang-song HUI
2011-11-01
Full Text Available Objective To investigate the physiological features of patients with psoriasis vulgaris during sleep.Methods Thirty-six psoriasis patients were classified into the group with "blood-heat" syndrome(n=21 and the group with "blood-dry" syndrome(n=15.Fifteen healthy volunteers served as control.All the subjects underwent a nocturnal sleep examination using the micro-movement sensitive mattress sleep monitoring system(MSMSMS.The sleep indices and nocturnal heart rate dynamics of the patients were compared with that of the control,and also between the two groups with different syndrome.Results In comparison with the control group,both psoriasis patient groups showed the phenomena of poor sleep quality,such as the shallow sleep phase,disorder of sleep rhythm and increased slight-arousals.The slight-arousal occurred more often in blood-heat syndrome group than in blood-dry syndrome group,while the sleep latency was elongated more evidently in blood-dry syndrome group.Compared with the control group,the two patient groups presented a little decrease in heart rate(HR after sleeping.However,the HR increased in the first phase of sleep,and the variation coefficient of HR increased in the whole sleep period.An increase in HR variation coefficient was more obvious in blood-heat syndrome group than in blood-dry syndrome group(P < 0.05.Conclusions The phenomena of decreased sleep quality and the variation of nocturnal HR in psoriasis patients may be due to the failure of Yin to control Yang,and disturbance of heat to the mind induced by blood-heat and Yin deficiency.The degrees of the phenomena are different between the two psoriasis groups.There is also a decrease in parasympathetic activity and relative increase in sympathetic activity in both psoriasis groups,with manifestation of different features in patients with different syndromes.
Adjoint sensitivity of global cloud droplet number to aerosol and dynamical parameters
Directory of Open Access Journals (Sweden)
V. A. Karydis
2012-10-01
Full Text Available We present the development of the adjoint of a comprehensive cloud droplet formation parameterization for use in aerosol-cloud-climate interaction studies. The adjoint efficiently and accurately calculates the sensitivity of cloud droplet number concentration (CDNC to all parameterization inputs (e.g., updraft velocity, water uptake coefficient, aerosol number and hygroscopicity with a single execution. The adjoint is then integrated within three dimensional (3-D aerosol modeling frameworks to quantify the sensitivity of CDNC formation globally to each parameter. Sensitivities are computed for year-long executions of the NASA Global Modeling Initiative (GMI Chemical Transport Model (CTM, using wind fields computed with the Goddard Institute for Space Studies (GISS Global Circulation Model (GCM II', and the GEOS-Chem CTM, driven by meteorological input from the Goddard Earth Observing System (GEOS of the NASA Global Modeling and Assimilation Office (GMAO. We find that over polluted (pristine areas, CDNC is more sensitive to updraft velocity and uptake coefficient (aerosol number and hygroscopicity. Over the oceans of the Northern Hemisphere, addition of anthropogenic or biomass burning aerosol is predicted to increase CDNC in contrast to coarse-mode sea salt which tends to decrease CDNC. Over the Southern Oceans, CDNC is most sensitive to sea salt, which is the main aerosol component of the region. Globally, CDNC is predicted to be less sensitive to changes in the hygroscopicity of the aerosols than in their concentration with the exception of dust where CDNC is very sensitive to particle hydrophilicity over arid areas. Regionally, the sensitivities differ considerably between the two frameworks and quantitatively reveal why the models differ considerably in their indirect forcing estimates.
Ammari, Zied
2011-01-01
We consider the quantum dynamics of many bosons systems in the mean field limit with a singular pair-interaction potential, including the attractive or repulsive Coulombic case in three dimensions. By using a measure transportation technique, we show that Wigner measures propagate along the nonlinear Hartree flow. Such property was previously proved only for bounded potentials in our previous works with a slightly different strategy.
Integrated, multi-parameter, investigation of eruptive dynamics at Santiaguito lava dome, Guatemala
Lavallée, Yan; De Angelis, Silvio; Rietbrock, Andreas; Lamb, Oliver; Hornby, Adrian; Lamur, Anthony; Kendrick, Jackie E.; von Aulock, Felix W.; Chigna, Gustavo
2016-04-01
Understanding the nature of the signals generated at volcanoes is central to hazard mitigation efforts. Systematic identification and understanding of the processes responsible for the signals associated with volcanic activity are only possible when high-resolution data are available over relatively long periods of time. For this reason, in November 2014, the Liverpool Earth Observatory (LEO), UK, in collaboration with colleagues of the Instituto Nacional de Sismologia, Meteorologia e Hidrologia (INSIVUMEH), Guatemala, installed a large multi-parameter geophysical monitoring network at Santiaguito - the most active volcano in Guatemala. The network, which is to date the largest temporary deployment on Santiaguito, includes nine three-component broadband seismometers, three tiltmeters, and five infrasound microphones. Further, during the initial installation campaign we conducted visual and thermal infrared measurements of surface explosive activity and collected numerous rock samples for geochemical, geophysical and rheological characterisation. Activity at Santiaguito began in 1922, with the extrusion of a series of lava domes. In recent years, persistent dome extrusion has yielded spectacularly episodic piston-like motion displayed by characteristic tilt/seismic patterns (Johnson et al, 2014). This cyclicity episodically concludes with gas emissions or gas-and-ash explosions, observed to progress along a complex fault system in the dome. The explosive activity is associated with distinct geophysical signals characterised by the presence of very-long period earthquakes as well as more rapid inflation/deflation cycles; the erupted ash further evidences partial melting and thermal vesiculation resulting from fault processes (Lavallée et al., 2015). One year of data demonstrates the regularity of the periodicity and intensity of the explosions; analysis of infrasound data suggests that each explosion expulses on the order of 10,000-100,000 kg of gas and ash. We
Induced two-body scattering resonances from a square-well potential with oscillating depth
Hudson Smith, D.
2016-03-01
In systems of ultracold atoms, pairwise interactions can be resonantly enhanced by a new mechanism which does not rely upon a magnetic Feshbach resonance. In this mechanism, interactions are controlled by tuning the frequency of an oscillating parallel component of the magnetic field close to the Bohr frequency for the transition to a two-atom bound state. The real part of the s-wave scattering length a has a resonance as a function of the oscillation frequency near the Bohr frequency. The resonance parameters can be controlled by varying the amplitude of the oscillating field. The amplitude also controls the imaginary part of a which arises predominantly because the oscillating field converts atom pairs into molecules. For the case of a shallow bound state in the scattering channel, the dimensionless resonance parameters are universal functions of the dimensionless oscillation amplitude.
Corrected Newtonian potentials in the two-body problem with applications
Anisiu, M -C
2016-01-01
The paper deals with an analytical study of various corrected Newtonian potentials. We offer a complete description of the corrected potentials, for the entire range of the parameters involved. These parameters can be fixed for different models in order to obtain a good concordance with known data. Some of the potentials are generated by continued fractions, and another one is derived from the Newtonian potential by adding a logarithmic correction. The zonal potential, which models the motion of a satellite moving in the equatorial plane of the Earth, is also considered. The range of the parameters for which the potentials behave or not similarly to the Newtonian one is pointed out. The shape of the potentials is displayed for all the significant cases, as well as the orbit of Raduga-1M 2 satellite in the field generated by the continued fractional potential U3, and then by the zonal one. For the continued fractional potential U2 we study the basic problem of the existence and linear stability of circular orb...
Corrected Newtonian potentials in the two-body problem with applications
Anisiu, M.-C.; Szücs-Csillik, I.
2016-12-01
The paper deals with an analytical study of various corrected Newtonian potentials. We offer a complete description of the corrected potentials, for the entire range of the parameters involved. These parameters can be fixed for different models in order to obtain a good concordance with known data. Some of the potentials are generated by continued fractions, and another one is derived from the Newtonian potential by adding a logarithmic correction. The zonal potential, which models the motion of a satellite moving in the equatorial plane of the Earth, is also considered. The range of the parameters for which the potentials behave or not similarly to the Newtonian one is pointed out. The shape of the potentials is displayed for all the significant cases, as well as the orbit of Raduga-1M 2 satellite in the field generated by the continued fractional potential U3, and then by the zonal one. For the continued fractional potential U2 we study the basic problem of the existence and linear stability of circular orbits. We prove that such orbits exist and are linearly stable. This qualitative study offers the possibility to choose the adequate potential, either for modeling the motion of planets or satellites, or to explain some phenomena at galactic scale.
Habarulema, J. B.; Katamzi, Z. T.; McKinnell, L. A.; Tshimangadzo, M.
2014-12-01
We report on the ongoing efforts of modelling and characterising the ionospheric dynamics over the African sector. We have investigated the usage of a combination of data sources (GPS, ionosonde, radio occultation) along with other geophysical parameters such as magnetic and solar activities to generate realistic ionospheric behaviour for both scientific understanding and application purposes. However a number of outstanding questions remain such as capturing all storm phases, and accurate validation of some data sources. This is in addition to complicated electrodynamics over the African sector coupled with significant data-gaps that hinder the development of truly representative modelling approaches. Our ultimate aim is to develop a model that can be used for accurately representing the ionospheric behaviour and can be utilised as a space weather product for application purposes. In this presentation, the current modelling options under investigation for ionospheric modelling and mapping over the African sector will be discussed.
Wu, Meihong; Liao, Lifang; Luo, Xin; Ye, Xiaoquan; Yao, Yuchen; Chen, Pinnan; Shi, Lei; Huang, Hui; Wu, Yunfeng
2016-01-01
Measuring stride variability and dynamics in children is useful for the quantitative study of gait maturation and neuromotor development in childhood and adolescence. In this paper, we computed the sample entropy (SampEn) and average stride interval (ASI) parameters to quantify the stride series of 50 gender-matched children participants in three age groups. We also normalized the SampEn and ASI values by leg length and body mass for each participant, respectively. Results show that the original and normalized SampEn values consistently decrease over the significance level of the Mann-Whitney U test (p algorithms were used to effectively distinguish the children's gait patterns. These ensemble learning algorithms both provided excellent gait classification results in terms of overall accuracy (≥90%), recall (≥0.8), and precision (≥0.8077).
The influence of selected design and operating parameters on the dynamics of the steam micro-turbine
Żywica, Grzegorz; Kiciński, Jan
2015-10-01
The topic of the article is the analysis of the influence of selected design parameters and operating conditions on the radial steam micro-turbine, which was adapted to operate with low-boiling agent in the Organic Rankine Cycle (ORC). In the following parts of this article the results of the thermal load analysis, the residual unbalance and the stiffness of bearing supports are discussed. Advanced computational methods and numerical models have been used. Computational analysis showed that the steam micro-turbine is characterized by very good dynamic properties and is resistant to extreme operating conditions. The prototype of micro-turbine has passed a series of test calculations. It has been found that it can be subjected to experimental research in the micro combined heat and power system.
Ogorodova, L M; Kulikov, E S; Deev, I A; Cherniak, B A; Fassakhov, R S
2011-01-01
Different strategies for disease control in real clinical practice are compared in terms of dynamics of functional parameters in patients with persistent bronchial asthma. This prospective multicentre surveillance study was carried out in 19 Russian clinics using the common protocol. The patients were divided in 3 groups in accordance with the changes of basal antiinflammatory therapy during the study period. Group A--stepwise increase in the extent of combined salmoterol/fluticason therapy, group B--long-term stable-dose salmoterol/fluticason therapy, group C--salmoterol/fluticason therapy with gradual decrease of the dose and/or transition to an alternative variant. Statistical analysis using Statistica 6.0 program included data from 543 patients. The results suggest that the two first modalities increased the level of control (ACT test) and improved characteristics of external respiration throughout the study period. Strategy 3 was associated with a decrease in the external respiration function and the level of control.
Verma, Ashok K.; Margot, Jean-Luc; Greenberg, Adam H.
2017-08-01
We evaluated the prospects of quantifying the parameterized post-Newtonian parameter β and solar quadrupole moment {J}2⊙ with observations of near-Earth asteroids with large orbital precession rates (9 to 27 arcsec century-1). We considered existing optical and radar astrometry, as well as radar astrometry that can realistically be obtained with the Arecibo planetary radar in the next five years. Our sensitivity calculations relied on a traditional covariance analysis and Monte Carlo simulations. We found that independent estimates of β and {J}2⊙ can be obtained with precisions of 6 × 10-4 and 3 × 10-8, respectively. Because we assumed rather conservative observational uncertainties, as is the usual practice when reporting radar astrometry, it is likely that the actual precision will be closer to 2 × 10-4 and 10-8, respectively. A purely dynamical determination of solar oblateness with asteroid radar astronomy may therefore rival the helioseismology determination.
Interacting quantum walkers: two-body bosonic and fermionic bound states
Krapivsky, P. L.; Luck, J. M.; Mallick, K.
2015-11-01
We investigate the dynamics of bound states of two interacting particles, either bosons or fermions, performing a continuous-time quantum walk on a one-dimensional lattice. We consider the situation where the distance between both particles has a hard bound, and the richer situation where the particles are bound by a smooth confining potential. The main emphasis is on the velocity characterizing the ballistic spreading of these bound states, and on the structure of the asymptotic distribution profile of their center-of-mass coordinate. The latter profile generically exhibits many internal fronts.
Lanspa, Michael J; Grissom, Colin K; Hirshberg, Eliotte L; Jones, Jason P; Brown, Samuel M
2013-02-01
Volume expansion is a mainstay of therapy in septic shock, although its effect is difficult to predict using conventional measurements. Dynamic parameters, which vary with respiratory changes, appear to predict hemodynamic response to fluid challenge in mechanically ventilated, paralyzed patients. Whether they predict response in patients who are free from mechanical ventilation is unknown. We hypothesized that dynamic parameters would be predictive in patients not receiving mechanical ventilation. This is a prospective, observational, pilot study. Patients with early septic shock and who were not receiving mechanical ventilation received 10-mL/kg volume expansion (VE) at their treating physician's discretion after initial resuscitation in the emergency department. We used transthoracic echocardiography to measure vena cava collapsibility index and aortic velocity variation before VE. We used a pulse contour analysis device to measure stroke volume variation (SVV). Cardiac index was measured immediately before and after VE using transthoracic echocardiography. Hemodynamic response was defined as an increase in cardiac index 15% or greater. Fourteen patients received VE, five of whom demonstrated a hemodynamic response. Vena cava collapsibility index and SVV were predictive (area under the curve = 0.83, 0.92, respectively). Optimal thresholds were calculated: vena cava collapsibility index, 15% or greater (positive predictive value, 62%; negative predictive value, 100%; P = 0.03); SVV, 17% or greater (positive predictive value 100%, negative predictive value 82%, P = 0.03). Aortic velocity variation was not predictive. Vena cava collapsibility index and SVV predict hemodynamic response to fluid challenge patients with septic shock who are not mechanically ventilated. Optimal thresholds differ from those described in mechanically ventilated patients.
Cristofolini, Andrea; Neretti, Gabriele; Borghi, Carlo A.
2012-08-01
This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of Hα and the Hβ lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.
Lanspa, Michael J.; Grissom, Colin K.; Hirshberg, Eliotte L.; Jones, Jason P.; Brown, Samuel M.
2013-01-01
Background Volume expansion is a mainstay of therapy in septic shock, although its effect is difficult to predict using conventional measurements. Dynamic parameters, which vary with respiratory changes, appear to predict hemodynamic response to fluid challenge in mechanically ventilated, paralyzed patients. Whether they predict response in patients who are free from mechanical ventilation is unknown. We hypothesized that dynamic parameters would be predictive in patients not receiving mechanical ventilation. Methods This is a prospective, observational, pilot study. Patients with early septic shock and who were not receiving mechanical ventilation received 10 ml/kg volume expansion (VE) at their treating physician's discretion after initial resuscitation in the emergency department. We used transthoracic echocardiography to measure vena cava collapsibility index (VCCI) and aortic velocity variation (AoVV) prior to VE. We used a pulse contour analysis device to measure stroke volume variation (SVV). Cardiac index was measured immediately before and after VE using transthoracic echocardiography. Hemodynamic response was defined as an increase in cardiac index ≥ 15%. Results 14 patients received VE, 5 of which demonstrated a hemodynamic response. VCCI and SVV were predictive (Area under curve = 0.83, 0.92, respectively). Optimal thresholds were calculated: VCCI ≥ 15% (Positive predictive value, PPV 62%, negative predictive value, NPV 100%, p = 0.03); SVV ≥ 17% (PPV 100%, NPV 82%, p = 0.03). AoVV was not predictive. Conclusions VCCI and SVV predict hemodynamic response to fluid challenge patients with septic shock who are not mechanically ventilated. Optimal thresholds differ from those described in mechanically ventilated patients. PMID:23324885
DEFF Research Database (Denmark)
Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian;
2011-01-01
of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set...
DEFF Research Database (Denmark)
2011-01-01
of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set......In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....