Brueckner correlations following a boson mapping of the two-color delta model
We study the application of boson mapping methods to a two-color delta model of interacting quarks, with the purpose of extracting information of relevance to quark-model descriptions of nuclei. In an earlier treatment, the boson Hamiltonian resulting from the mapping was approximately diagonalized at the level of Hartree-Bose approximation. The results differed from those of an exact solution of the model at first order in the density. Furthermore, the results were worse than those arising from a BCS treatment of pair correlations at the quark level. Here we extend the analysis to a Brueckner treatment, so as to properly take into account the short-range repulsion between bosons originating from the quark Pauli principle. The resulting energy per quark reproduces the exact results through first order in the density and is significantly better than the BCS results. At higher densities, deviations appear, reflecting the need for a full cluster expansion in the treatment of short-range correlation effects. The relevance of these results to more realistic three-color quark models of nuclei is discussed. copyright 1996 The American Physical Society
Testing Dirac-Brueckner models in collective flow of heavy-ion collisions
We investigate differential in-plane and out-of-plane flow observables in heavy-ion reactions at intermediate energies from 0.2-2 AGeV within the framework of relativistic BUU transport calculations. The mean field is based on microscopic Dirac-Brueckner-Hartree-Fock (DB) calculations. We apply two different sets of DB predictions, those of ter Haar and Malfliet and more recent ones from the Tuebingen group, which are similar in general but differ in details. The latter DB calculations exclude spurious contributions from the negative-energy sector to the mean field which results in a slightly softer equation of state and a less repulsive momentum dependence of the nucleon-nucleus potential at high densities and high momenta. For the application to heavy-ion collisions in both cases non-equilibrium features of the phase space are taken into account on the level of the effective interaction. The systematic comparison to experimental data favours the less repulsive and softer model. Relative to non-relativistic approaches one obtains larger values of the effective nucleon mass. This produces a sufficient amount of repulsion to describe the differential flow data reasonably well. (orig.)
Kambe, Takahide; Saito, Koichi
2016-01-01
As the interior density of a neutron star can become very high, it has been expected and discussed that quark matter may exist inside it. To describe the transition from hadron to quark phases (and vice versa), there are mainly two methods; one is the first-order phase transition, and the other is the crossover phenomenon. In the present study, using the flavor-SU (3) NJL model with the vector coupling interaction, we have calculated the equation of state for the quark phase at high density. Furthermore, for the hadron phase at low density, we have used two kinds of the equations of state; one is a relatively soft one by the QHD model, and the other is a stiff one calculated with relativistic Brueckner-Hartree-Fock approximation. Using those equations of state for the two phases, we have investigated the influence of various choices of parameters concerning the crossover region on the mass and radius of a neutron star.
Brockmann, R.; Machleidt, R.
1996-01-01
In this review, we give a thorough introduction into the Dirac-Brueckner approach including the mathematical details of the formalism involved. Furthermore, we present results for nuclear matter, NN scattering in the nuclear medium, and finite nuclei.
Brueckner-AMD Study of Light Nuclei
We applied the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD) and examined the reliability of the AMD calculations based on realistic nuclear interactions. In this method, the Bethe-Goldstone equation in the Brueckner theory is solved for every nucleon pair described by wave packets of AMD, and the G-matrix is calculated with single-particle orbits in AMD self-consistently. We apply this framework to not only α-nuclei but also N≠Z nuclei with A∼10. It is confirmed that these results present the description of reasonable cluster structures and energy-level schemes comparable with the experimental ones in light nuclei.
Brueckner-AMD study of light nuclei
We applied the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD), and show the reliability of the AMD calculations based on realistic nuclear interactions. Focusing our interest on a structure dependence of the tensor force, we investigate the α-α clusterization of 8Be. (author)
Brueckner-AMD study of light nuclei
In many states of light nuclei, the cluster structure is observed in addition to the shell structure. To understand the mechanism of clustering, we apply the Brueckner theory to the Antisymmetrized Molecular Dynamics (AMD) based on realistic nuclear interactions. The Bethe-Goldstone equation in the Brueckner theory is solved for every nucleon pair described by wave packets of AMD, and the G-matrix is calculated with single-particle orbits in AMD self-consistently. We show applicability of this method not only to self-conjugate nuclei but also to N ≠ Z nuclei with A ≤ 12. It is confirmed that these results present reasonable description of cluster structures and energy-level schemes in comparison with the experimental ones in light nuclei. For 8Be having a typical α + α cluster structure, the structure dependence of the G-matrix is investigated and the role of tensor force is shown to be important in understanding the clustering mechanism.
Momentum-dependent mean field based upon the Dirac-Brueckner approach for nuclear matter
A momentum-dependent mean field potential, suitable for application in the transport-model description of nucleus-nucleus collisions, is derived in a microscopic way. The derivation is based upon the Bonn meson-exchange model for the nucleon-nucleon interaction and the Dirac-Brueckner approach for nuclear matter. The properties of the microscopic mean field are examined and compared with phenomenological parametrizations which are commonly used in transport-model calculations
Relativistic meson-exchange NN-interaction and nuclear matter in the Dirac-Brueckner approach
Starting from the full Bonn meson-exchange model for the NN-interaction an OBEP is constructed in the framework of the Thompson version of the Blankenbecler-Sugar reduction of the Bethe-Salpeter equation. The pseudo-vector coupling of the pion to the nucleon is assumed. An excellent quantitative description of the deuteron and the latest phase-shift analyses of NN-scattering is achieved. This potential is applied to the system of infinite nuclear matter in the relativistic Dirac-Brueckner approach. Due to additional strongly density dependent relativistic saturation effects, which do not occur in conventional Brueckner theory, the empirical saturation energy and density of nuclear matter are reproduced. This potential may serve as a good starting point for the evaluation of the optical potential to be applied in nucleon-nucleus scattering
Relativistic Brueckner-Hartree-Fock theory for finite nuclei
Shen, Shihang; Liang, Haozhao; Meng, Jie; Ring, Peter; Zhang, Shuangquan
2016-01-01
Starting with a bare nucleon-nucleon interaction, for the first time the full relativistic Brueckner-Hartree-Fock equations are solved for finite nuclei in a Dirac-Woods-Saxon basis. No free parameters are introduced to calculate the ground-state properties of finite nuclei. The nucleus $^{16}$O is investigated as an example. The resulting ground-state properties, such as binding energy and charge radius, are considerably improved as compared with the non-relativistic Brueckner-Hartree-Fock results and much closer to the experimental data. This opens the door for \\emph{ab initio} covariant investigations of heavy nuclei.
The description of nuclear structures with the Brueckner-AMD
We propose a new approach of the Brueckner-AMD that makes the antisymmetrized molecular dynamics (AMD) calculations possible with realistic nuclear forces. In this method, we solve the Bethe-Goldstone equation and calculate the G-matrix for every nucleon pair described by wave packets of AMD. In addition, we calculate the G-matrix in the spin and parity projection correctly using the two-body correlation functions derived from the solutions of the Bethe-Goldstone equation. We report the results of applications to light nuclei with the Brueckner-AMD plus the spin and parity projection. (author)
The study of light nuclei with the Brueckner-AMD
We propose a new approach of the Brueckner-AMD that makes the antisymmetrized molecular dynamics (AMD) calculations possible with realistic nuclear forces. In this method, we solve the Bethe-Goldstone equation and calculate the G-matrix for every nucleon pair described by wave packets of AMD. In addition, we perform the spin and parity projection correctly using the two-body correlators derived from the solutions of the Bethe-Goldstone equation. We report the results of applications to light nuclei with the Brueckner-AMD plus the spin and parity projection
The Bonn-potential and the relativistic Dirac-Brueckner approach to nuclear matter
A relativistic form of the Brueckner theory of nuclear matter is applied to an extended meson-exchange model for the NN-interaction containing explicit 2/sub π-/ and πrho-exchanges. It turns out that the relativistic saturation effects found earlier within the simplified one-boson-exchange (OBE) model maintain within this extended and more realistic model. In particular it is found that the relativistic effects caused by the explicit 2/sub π-/ and πrho-exchanges are well simulated by the fictitious σ-boson of the OBE model
Brueckner-AMD method and its applications to light nuclei
We propose a new approach employing the Brueckner-AMD in which the G-matrix is calculated using the antisymmetrized molecular dynamics (AMD). Its applications to some light nuclei are demonstrated, and the high reliability of the description of the shell and cluster structures is discussed. (author)
Nucleon self-energy in the relativistic Brueckner theory
Waindzoch, T.; Fuchs, C.; Faessler, A. [Inst. fuer Theoretische Physik, Univ. Tuebingen (Germany)
1998-06-01
The self-energy of the nucleon in nuclear matter is calculated in the relativistic Brueckner theory. We solve the Thompson equation for the two nucleon scattering in the medium using different Bonn potentials. The self-energy has a rather strong momentum dependence while the equation of state compares well with previous calculations. (orig.)
From Brueckner approach to Skyrme-type energy density functional
A Skyrme-like effective interaction is built up from the equation of state of nuclear matter. The latter is calculated in the framework of the Brueckner-Hartree-Fock approximation with two- and three-body forces. A complete Skyrme parametrization requires a fit of the neutron and proton effective masses and the Landau parameters. The new parametrization is probed on the properties of a set of closed-shell and closed-subshell nuclei, including binding energies and charge radii
The Relativistic Dirac-Brueckner Approach to Nuclear Matter
Fuchs, Christian
2003-01-01
An overview on the relativistic Dirac-Brueckner approach to the nuclear many-body problem is given. Different approximation schemes are discussed, with particular emphasis on the nuclear self-energy and the saturation mechanism of nuclear matter. I will further discuss extensions of the standard approach, amongst other things the inclusion of non-nucleonic degrees of freedom, many-body forces and finally compare relativistic and non-relativistic approaches.
Brueckner rearrangement energies in s-shell hypernuclei
We consider rearrangement effects in light hypernuclei in the framework of the lowest order Brueckner theory. The energy change of the 4He core of Λ5He when the Λ hyperon is added to 4He is first estimated without much numerical computations. Next, rearrangement contributions in ΔΒΛΛ(ΛΛ6He) are estimated, which are important to deduce the strength of the ΛΛ interaction from the experimental ΔΒΛΛ(ΛΛ6He). (author)
Description of nuclear structures in light nuclei with Brueckner-AMD
Katō K.; Yamamoto Y; Togashi T.
2010-01-01
We develop the new antisymmetrized molecular dynamics (AMD) method, Brueckner-AMD, which makes us perform the AMD calculations starting from the realistic nuclear force. In the Brueckner-AMD, the single-particle orbits of AMD can be applied straightforward to the Bethe-Goldstone equation in the Brueckner theory by using the AMD+Hartree-Fock method, and the G-matrices are determined with the single-particle energies of AMD self-consistently. In that sense, in this framework, the G-matrix...
On the effective sigma-boson exchange in the relativistic Dirac-Brueckner approach to nuclear matter
A relativistic form of the Brueckner theory of nuclear matter is applied to an extended meson-exchange model for the NN-interaction which contains explicit 2π-and πrho-exchange. This model avoids the effective sigma-boson which is characteristic of the simplified meson exchange, as e.g. the one-boson-exchange (OBE) potential. It turns out that the relativistic saturation effects found earlier within the OBE model are confirmed by the extended and more realistic model. In particular it is found that the relativistic effects caused by the explicit 2π- and πrho-exchange are well simulated by the effective sigma-boson of the OBE model. (orig.)
Structures of the Vela pulsar and the glitch crisis from the Brueckner theory
Li, A; Wang, J B; Xu, R X
2015-01-01
Detailed structures of the Vela pulsar (PSR B0833-45, with a period of $89.33$ milliseconds) are predicted by adopting a recently-constructed unified treatment of all parts of neutron stars: the outer crust, the inner crust and the core based on modern microscopic Brueckner-Hartree-Fock calculations. To take the pulsar mass ranging from $1.0M_{\\odot}$ to $2.0M_{\\odot}$, we calculate the central density, the core/crust radii, the core/crust mass, the core/crustal thickness, the moment of inertia, and the crustal moment of inertia. Among them, the crustal moment of inertia could be effectively constrained from the accumulated glitch observations, which has been a great debate recently, known as "glitch crisis". Namely, superfluid neutrons contained in the inner crust, which are regarded as the origin of the glitch in the standard two-component model, could be largely entrained in the nuclei lattices, then there may not be enough superfluid neutrons ($\\sim 4/5$ less than the previous value) to trigger the large ...
Brueckner-Hartree-Fock and its renormalized calculations for finite nuclei
Hu, B S; Ma, Y Z; Wu, Q; Sun, Z H
2016-01-01
We have performed self-consistent Brueckner-Hartree-Fock (BHF) and its renormalized theory to the structure calculations of finite nuclei. The $G$-matrix is calculated within the BHF basis, and the exact Pauli exclusion operator is determined by the BHF spectrum. Self-consistent occupation probabilities are included in the renormalized Brueckner-Hartree-Fock (RBHF). Various systematics and convergences are studies. Good results are obtained for the ground-state energy and radius. RBHF can give a more reasonable single-particle spectrum and radius. We present a first benchmark calculation with other {\\it ab initio} methods using the same effective Hamiltonian. We find that the BHF and RBHF results are in good agreement with other $\\it{ab}$ $\\it{initio}$ methods.
The Bethe-Brueckner-Goldstone expansion in nuclear and neutron matter
The microscopic theory of nuclear matter is developed within the Bethe-Brueckner-Goldstone expansion. Starting from different realistic nucleon-nucleon interactions, the equation of state of symmetric nuclear matter and pure neutron matter is calculated up to three-hole level of approximation. The expansion shows to be convergent up to densities relevant for neutron stars studies. Within the same scheme, the nucleon strength function is calculated in the kinematical region pertinent to deep inelastic electron scattering. (author)
Nucleon effective mass in symmetric nuclear matter from the extended Brueckner-Hartree-Fock approach
GAN Sheng-Xin; ZUO Wei; U. Lombardo
2012-01-01
We have calculated the nucleon effective mass in symmetric nuclear matter within the framework of the Brueckner-Bethe-Goldstone (BBG) theory,which has been extended to include both the contributions from the ground-state correlation effect and the three-body force (TBF) rearrangement effect.The effective mass is predicted by including the ground-state correlation effect and the TBF rearrangement effect,and we discuss the momentum dependence and the density dependence of the effective mass.It is shown that the effect of ground state correlations plays an important role at low densities,while the TBF-induced rearrangement effect becomes predominant at high densities.
Neutron stars with Hyperons in Dirac-Brueckner-Hartree-Fock approach
Katayama, Tetsuya; Saito, Koichi
2014-01-01
Using the Dirac-Brueckner-Hartree-Fock (DBHF) approach including the hyperon degrees of freedom, we investigate the properties of neutron-star matter. To handle the hyperons in matter, we first examine the importance of the space part of baryon self-energies at high densities, and secondly study the effect of negative-energy states of baryons, which can provide an unambiguous relationship between the in-medium reaction matrices for baryon-baryon scattering and the baryon self-energies. We sol...
Density dependence of microscopic nucleon optical potential in first order Brueckner theory
In the present work we apply the lowest order Brueckner theory of infinite nuclear matter to obtain nucleon-nucleus optical potential for p-40Ca elastic scattering at 200 MeV using Urbana V14 soft core internucleon potential. We have investigated the effect of target density on the calculated nucleon-nucleus optical potential. We find that the calculated optical potentials depend quite sensitively on the density distribution of the target nucleus. The important feature is that the real part of calculated central optical potential for all densities shows a wine-bottle-bottom type behaviour at this energy. We also discuss the effect of our new radial dependent effective mass correction. Finally, we compare the prediction of our calculated nucleon optical potential using V14 with the prediction using older hard core Hamada-Johnston internucleon potential for p-40Ca elastic scattering at 200 MeV. (author)
The use of off-shell potentials in Brueckner theory calculations of the nucleon optical potential
We calculate the nucleon optical-potential from the Hamada-Johnston potential using firstorder Brueckner theory. The new feature is that we use a fully complex off-shell potential in the energy denominator in the calculation of the t-matrix in place of the usually used real part of the on-shell potential. We find that for bombarding energies near 30 MeV the agreement with experimental data is satisfactory while at higher energies the general results from the on- and off-shell potentials are very similar. The reason for the better agreement at the lower energies using the off-shell potential in the energy denominator is that the calculated optical potential in this case has a much smaller imaginary part. (orig.)
A New Decomposition Approach of Dirac Brueckner Hartree-Fock G Matrix for Asymmetric Nuclear Matter
刘玲; 马中玉
2002-01-01
Asymmetric nuclear matter is investigated by the Dirac Brueckner Hartree-Fock (DBHF) approach with a new decomposition of the Dirac structure of nucleon self-energy from the G matrix. It is found that the isospin dependence of the scalar and vector potentials is relatively weak, although both potentials for neutron (proton)become deep (shallow) in the neutron-rich nuclear matter. The results in asymmetric nuclear matter are rather different from those obtained by a simple method, where the nucleon self-energy is deduced from the single-particle energy. The nuclear binding energy as a function of the asymmetry parameter fulfils the empirical parabolic law up to very extreme isospin asymmetric nuclear matter in the DBHF approach. The behaviour of the density dependence of the asymmetry energy is different from that obtained by non-relativistic approaches, although both give similar asymmetry energy at the nuclear saturation density.
RONG Jian; MA Zhongyu
2004-01-01
The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E＞ 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.
Properties of dense, asymmetric nuclear matter in Dirac-Brueckner-Hartree-Fock approach
Katayama, Tetsuya
2013-01-01
Within the Dirac-Brueckner-Hartree-Fock approach, using the Bonn potentials, we investigate the properties of dense, asymmetric nuclear matter and apply it to neutron stars. In the actual calculations of the nucleon self-energies and the energy density of matter, we study in detail the validity of an angle-averaged approximation and an averaging of the total momentum squared of interacting two-nucleons in nuclear matter. For practical use, we provide convenient parametrizations for the equation of state for symmetric nuclear matter and pure neutron matter. We also parametrize the nucleon self-energies in terms of polynomials of nucleon momenta. Those parametrizations can accurately reproduce the numerical results up to high densities.
Neutron stars with Hyperons in Dirac-Brueckner-Hartree-Fock approach
Katayama, Tetsuya
2014-01-01
Using the Dirac-Brueckner-Hartree-Fock (DBHF) approach including the hyperon degrees of freedom, we investigate the properties of neutron-star matter. To handle the hyperons in matter, we first examine the importance of the space part of baryon self-energies at high densities, and secondly study the effect of negative-energy states of baryons, which can provide an unambiguous relationship between the in-medium reaction matrices for baryon-baryon scattering and the baryon self-energies. We solve the coupled, Bethe-Salpeter equations in the nuclear-matter rest frame by using the Bonn potentials. We assume that eight kinds of nonstrange and strange mesons ($\\sigma,\\,\\delta,\\,\\omega,\\,\\rho,\\,\\eta,\\,\\pi,\\,K,\\,K^{\\ast}$) take part in the interactions between two baryons. Then, we calculate the baryon self-energies, the energy density and pressure of matter. The present calculation provides a hard equation of state in neutron-star matter at high densities, which is generated by the effect of Pauli exclusion, the sho...
Validity of Brueckner theory for the nucleon optical potential near 200 MeV
A comparison is made of the experimental cross sections for proton scattering from 12C, 40Ca and 208Pb near 200 MeV bombarding energy with the results obtained from optical potentials calculated from Brueckner theory. We confirm the results of earlier analyses that the calculated potentials cannot reproduce the experimental data. It is shown that the calculated imaginary part of the potentials is completely satisfactory and that it is the calculated real part which leads to the discrepancy between theory and experiment. The real part is found to have the wrong radial shape, it has too extreme a 'wine bottle' shape. We show that this is a consequence of the calculated dependence of the t-matrix on the internucleon separation, in particular on the very different ranges for the attractive and repulsive parts. This is a consequence of our use of a hard-core internucleon potential and we suggest that a soft-core or momentum-dependent potential might give a better account of the experimental data. (orig.)
Iso-spin Dependent Microscopic Optical Model Potential Based on Dirac Bruckner Haretree Fock Method
无
2011-01-01
The microscopic optical model is investigated in the Dirac-Brueckner-Hartree-Fock (DBHF) framework with Bonn B meson exchange potential. Both real and imaginary parts of isospin-dependent self-energies are derived from a strict projection
Kohno, M
2015-01-01
The nuclear saturation mechanism is discussed in terms of two-nucleon and three-nucleon interactions in chiral effective field theory (Ch-EFT), using the framework of lowest-order Brueckner theory. After the Coester band, which is observed in calculating saturation points with various nucleon-nucleon (NN) forces, is revisited using modern NN potentials and their low-momentum equivalent interactions, detailed account of the saturation curve of the Ch-EFT interaction is presented. The three-nucleon force (3NF) is treated by reducing it to an effective two-body interaction by folding the third nucleon degrees of freedom. Uncertainties due to the choice of the 3NF low-energy constants $c_D$ and $c_E$ are discussed. The reduction of the cutoff-energy dependence of the NN potential is explained by demonstrating the effect of the 3NF in the $^1$S$_0$ and $^3$S$_1$ states.
Kohno, M.
2015-12-01
The nuclear saturation mechanism is discussed in terms of two-nucleon and three-nucleon interactions in chiral effective field theory (Ch-EFT), using the framework of lowest-order Brueckner theory. After the Coester band, which is observed in calculating saturation points with various nucleon-nucleon (NN) forces, is revisited using modern NN potentials and their low-momentum equivalent interactions, a detailed account of the saturation curve of the Ch-EFT interaction is presented. The three-nucleon force (3NF) is treated by reducing it to an effective two-body interaction by folding the third nucleon degrees of freedom. Uncertainties due to the choice of the 3NF low-energy constants c_D and c_E are discussed. The reduction of the cutoff-energy dependence of the NN potential is explained by demonstrating the effect of the 3NF in the ^1S_0 and ^3S_1 states.
Hypernucleus-16O in the density-dependent Hartree approach based on the chiral-σ model
A relativistic density-dependent interaction has been used to study hypernucleus 16O. The density-dependent coupling constants of the relativistic effective Hartree-Lagrangian are obtained from the relativistic Brueckner-Bethe-Goldstone results of nuclear matter in the chiral-σ model. With these density-dependent coupling constants, the bound states and the single-particle energy spectra of the hypernuclei Λ16O and Σ16O are obtained. The theoretical results of Λ16O are in agreement with the experimental data fairly well
Neutron matter under strong magnetic fields: a comparison of models
Aguirre, R; Vidaña, I
2013-01-01
The equation of state of neutron matter is affected by the presence of a magnetic field due to the intrinsic magnetic moment of the neutron. Here we study the equilibrium configuration of this system for a wide range of densities, temperatures and magnetic fields. Special attention is paid to the behavior of the isothermal compressibility and the magnetic susceptibility. Our calculation is performed using both microscopic and phenomenological approaches of the neutron matter equation of state, namely the Brueckner--Hartree--Fock (BHF) approach using the Argonne V18 nucleon-nucleon potential supplemented with the Urbana IX three-nucleon force, the effective Skyrme model in a Hartree--Fock description, and the Quantum Hadrodynamic formulation with a mean field approximation. All these approaches predict a change from completely spin polarized to partially polarized matter that leads to a continuous equation of state. The compressibility and the magnetic susceptibility show characteristic behaviors, which reflec...
Antonov, A N; Sarriguren, P; de Guerra, E Moya
2016-01-01
The volume and surface components of the nuclear symmetry energy (NSE) and their ratio are calculated within the coherent density fluctuation model (CDFM). The estimations use the results of the model for the NSE in finite nuclei based on the Brueckner energy-density functional for nuclear matter. In addition, we present results for the NSE and its volume and surface contributions obtained by using the Skyrme energy-density functional. The CDFM weight function is obtained using the proton and neutron densities from the self-consistent HF+BCS method with Skyrme interactions. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains studying their isotopic sensitivity. The results are compared with estimations of other approaches which have used available experimental data on binding energies, neutron-skin thicknesses, excitation energies to isobaric analog states (IAS) and also with results of other theoretical methods.
Optical-model potential in a relativistic quantum field model
Jaminon, M.; Mahaux, C.; Rochus, P.
1980-11-01
The average nucleon-nucleus potential at low and medium energy is investigated in the framework of a relativistic quantum field model. Using the same input parameters as Brockmann in his recent study of nuclear ground states, we calculate the self-consistent relativistic Hartree potential at positive energy in the case of infinite nuclear matter and of /sup 16/O and /sup 40/Ca. This potential is the sum of a scalar operator and of the fourth component of a vector operator. We construct its Schroedinger-equivalent potential by eliminating the small component of the Dirac spinor. The central part of this Schroedinger-equivalent potential is in fair agreement with empirical values at low and intermediate energy. Particular attention is paid to the intermediate energy domain, in which the calculated potential is repulsive in the nuclear interior and attractive at the nuclear surface. This is in keeping with some empirical evidence and is similar to results found in the framework of the nonrelativistic Brueckner-Hartree-Fock approximation. The spin-orbit potential of the relativistic Hartree model is also in good agreement with empirical values.
Isobar contributions to the imaginary part of the optical-model potential for finite nuclei
A recently developed non-relativistic method for calculating the nucleon optical-model potential has been employed to evaluate the contributions from isobaric degrees of freedom to the imaginary part of the nucleon optical-model potential. To evaluate the imaginary part of the optical-model potential, the authors include the contributions from terms to second order in the Brueckner G-matrix with and without the inclusion of isobars Δ. Results for 16O are presented in this work. The contributions to the imaginary part are given by the two-particle-one-hole (2p1h) and three-particle-two-hole (3p2h) diagrams. The latter contributes at negative energies only and the contribution from isobar intermediate states is rather small. The 2p1h receives significant contributions from isobars at energies near the resonance and above the threshold for the excitation of ΔΔ states. In particular, the importance of ΔΔ configurations is rather sensitive to the treatment of short-range correlations. The parameterization of the self-energy in terms of local potentials is discussed. The depletion of the occupation of the single-particle orbits due to nucleon-nucleon correlations and Δ excitations is evaluated. 49 refs., 14 figs., 3 tabs
Hyperon-hyperon interactions with the Nijmegen ESC08 model
Rijken, T.A. [Radboud University, IMAPP, AJ Nijmegen (Netherlands); Schulze, H.J. [Universita di Catania, Dipartimento di Fisica, Catania (Italy); INFN, Catania (Italy)
2016-02-15
We discuss the properties of the hyperon-hyperon interactions in the recent Nijmegen ESC08 potential, in particular the importance of the coupled-channel structure and related existence of bound states. Brueckner-Hartree-Fock calculations of hypernuclear matter employing these interactions are presented and the structure of hyperon (neutron) stars within this approach is computed. Low maximum masses are found. (orig.)
From nuclear matter to finite nuclei. Pt. 2
We discuss various relativistic models describing ground-state properties of spherical nuclei, are discussed. Relativistic mean-field and Hartree-Fock theories, which serve as a startingpoint for subsequent models, are reviewed. Using a density-dependent parametrization of the Dirac-Brueckner G-matrix in nuclear matter, we achieve an effective Dirac-Brueckner-Hartree-Fock model for finite nuclei. Finite nuclei results obtained with this model are compared with the less advanced Density-Dependent Mean-Field model, which simulates Dirac-Brueckner calculations for nuclear matter as well. It is shown that the effective Dirac-Brueckner-Hartree-Fock approach most successfully reproduces experimental data concerning spherical nuclei. (orig.)
Status of semi-classical distorted wave (SCDW) model
Watanabe, Y.; Higashi, H.; Kuwata, R.; Kawai, M. [Kyushu Univ., Fukuoka (Japan); Kohno, M.
1997-05-01
The SCDW model to describe the preequilibrium MSD reaction was extended so as to include the 3-step process. The MSD calculations of {sup 58}Ni(p,p`x) at energies of 65, 120 and 200 MeV and {sup 90}Zr(p,p`x) at 160 MeV were carried out using the extended SCDW model and compared with the experimental data. The calculations with no free parameter showed overall good agreement with the experiment, although underprediction is seen at very small and backward angles. We found that the 2- and 3-step contributions were not so large enough to compensate the difference between the 1-step cross sections and the experimental ones at backward angles. The discrepancies seen at very small and large angles is possibly responsible for the local Fermi-gas model which does not work well in the nuclear surface region. The comparisons of the SCDW calculations with the AMD, QMD and FKK calculations led to an interesting result that the differences in the shape of 1-step angular distributions are remarkable among the models, but the multistep components are rather similar in the shape of angular distributions and the step-wise contribution is not so much different. The in-medium N-N cross sections were calculated in the nonrelativistic Brueckner framework with the Paris potential, and were parametrized as a function of the incident energy and the nuclear density. The SCDW calculation with the in-medium N-N cross sections was not so different from that with the free ones. (J.P.N.)
Exact calculation of nucleon nucleus spin orbit potential in Brueckner theory
We have calculated the direct part of the spin orbit potential for the scattering of protons from 16O, 40Ca, 90Zr and 208Pb at 65 MeV to make a comparison of the spin orbit obtained by BR and our results obtained after removing the approximations which were assumed by BR. We have calculated the potential for different targets so as to study the mass number dependence of the calculated direct and imaginary parts of the spin orbit potential. We have employed Argonne v18 inter nucleon potential to solve Bethe-Goldstone integral equation to obtain t- matrices which were then folded numerically over the target densities. Effective mass correction has also been taken into account during the calculations. The nucleon densities used for the four targets were calculated using Relativistic mean field theory
The Brueckner-Hartree-Fock Equation of State for Nuclear Matter and Neutron Skin
Qing-Yang, Bu; Zeng-Hua, Li; Hans-Josef, Schulze
2016-03-01
Not Available Supported by the National Natural Science Foundation of China under Grant Nos 11075037 and 11475045, the Scientific Research Foundation for the Returned Overseas Chinese Scholars of the Ministry of Education of China, the Fundamental Research Funds for the Central Universities of China, the Shanghai Leading Academic Discipline Project under Grant No B107, and the ‘NewCompStar’, COST Action MP1304.
Microscopic Optical Potential of α-Nucleus Elastic Scattering
2008-01-01
<正>The nucleon microscopic optical model potentials (OMP) in the nuclear medium are studied in the framework of the Dirac-Brueckner-Hartree-Fock approach, which are of density- and energy-dependence.
Khoa, Dao T; Cuong, Do Cong
2007-01-01
A consistent folding model analysis of the ($\\Delta S=0, \\Delta T=1$) charge exchange \\pn reaction measured with $^{48}$Ca, $^{90}$Zr, $^{120}$Sn and $^{208}$Pb targets at the proton energies of 35 and 45 MeV is done within a two-channel coupling formalism. The nuclear ground state densities given by the Hartree-Fock-Bogoljubov formalism and the density dependent CDM3Y6 interaction were used as inputs for the folding calculation of the nucleon optical potential and \\pn form factor. To have an accurate isospin dependence of the interaction, a complex isovector density dependence of the CDM3Y6 interaction has been carefully calibrated against the microscopic Brueckner-Hatree-Fock calculation by Jeukenne, Lejeune and Mahaux before being used as folding input. Since the isovector coupling was used to explicitly link the isovector part of the nucleon optical potential to the cross section of \\pn reaction exciting the 0$^+$ isobaric analog states in $^{48}$Sc, $^{90}$Nb, $^{120}$Sb and $^{208}$Bi, the newly paramet...
A fully microscopic model of 200 MeV proton-12C elastic and inelastic scattering
An effective two nucleon (NN) interaction in the nuclear medium is defined from an accurate mapping of the NN g matrices obtained by solving the Brueckner-Bethe-Goldstone equations for infinite nuclear matter. That effective interaction is used in a fully microscopic calculation of the nonlocal effective proton-12C interaction from which are obtained predictions of the differential cross section and analysing power for 200 MeV elastic scattering. The relative motion wave functions so found are used as the distorted waves in a distorted wave approximation (DWA) study of select inelastic scattering events. The effective NN interaction is used as the transition operator in those calculations. The relevant nuclear spectroscopy for the elastic and DWA (p, p') calculations is found from a full (0 + 2) ℎω shell model evaluation of the positive parity states while a restricted (1 + 3)ℎω has been used to give the negative parity states. Results are compared with those of the 0p-shell model of Cohen and Kurath or with those based upon axially symmetric, projected Hartree-Fock calculations. The diverse structure model wave functions are assessed by using them in calculations to compare with measured longitudinal, transverse electric and transverse magnetic form factors from electron scattering to many of the excited states of 12C. Using those models of the structure of 12C in the completely microscopic model of the elastic and inelastic scattering of 200 MeV protons, good fits have been found to the cross section and analysing power data. 50 refs., 3 tabs., 20 figs
A fully microscopic model of 200 MeV proton-{sup 12}C elastic and inelastic scattering
Karataglidis, S.; Dortmans, P.J.; Amos, K.; de Swiniarski, R.
1996-03-01
An effective two nucleon (NN) interaction in the nuclear medium is defined from an accurate mapping of the NN g matrices obtained by solving the Brueckner-Bethe-Goldstone equations for infinite nuclear matter. That effective interaction is used in a fully microscopic calculation of the nonlocal effective proton-{sup 12}C interaction from which are obtained predictions of the differential cross section and analysing power for 200 MeV elastic scattering. The relative motion wave functions so found are used as the distorted waves in a distorted wave approximation (DWA) study of select inelastic scattering events. The effective NN interaction is used as the transition operator in those calculations. The relevant nuclear spectroscopy for the elastic and DWA (p, p`) calculations is found from a full (0 + 2) {Dirac_h}{omega} shell model evaluation of the positive parity states while a restricted (1 + 3){Dirac_h}{omega} has been used to give the negative parity states. Results are compared with those of the 0p-shell model of Cohen and Kurath or with those based upon axially symmetric, projected Hartree-Fock calculations. The diverse structure model wave functions are assessed by using them in calculations to compare with measured longitudinal, transverse electric and transverse magnetic form factors from electron scattering to many of the excited states of {sup 12}C. Using those models of the structure of {sup 12}C in the completely microscopic model of the elastic and inelastic scattering of 200 MeV protons, good fits have been found to the cross section and analysing power data. 50 refs., 3 tabs., 20 figs.
Microscopic model analyses of the elastic scattering of 65 MeV protons from targets of diverse mass
Nonlocal coordinate space optical potentials for the scattering of 65 MeV protons from nuclei ranging in mass from 6Li to 238U have been defined by folding a complex, medium dependent effective interaction with the density matrix elements of each target. The effective interaction is based upon solutions of the Lippmann-Schwinger and Brueckner-Bethe-Goldstone equations having the Paris potential as input. The nuclear structure information required in our folding model are the one body density matrix elements for the target and the single nucleon bound state wave functions that they weight. For light mass nuclei, very large basis shell model calculations have been made to obtain the one body density matrix elements. For medium and heavy mass nuclei, a very simple shell model prescription has been used. The bound state single particle wave functions that complete the nuclear density matrices are either Woods-Saxon or harmonic oscillator functions. The former are employed in most cases when large basis structure is available. For light nuclei (A ≤ 16) Woods-Saxon potential parameters and harmonic oscillators lengths are determined from fits to electron scattering form factors. For all other nuclei, we use harmonic oscillator functions with the oscillator lengths set from an A1/6 mass law. Using this microscopic model, optical potentials result from with differential cross sections, analyzing powers and spin rotations are found. In general the calculated results compare very well with data when the effective interactions are determined from a mapping of nucleon-nucleon g matrices. This is not the case when effective interactions built from a mapping of (free) t matrices are used. (authors)
Juel-Christiansen, Carsten
2005-01-01
Artiklen fremhæver den visuelle rotation - billeder, tegninger, modeller, værker - som det privilligerede medium i kommunikationen af ideer imellem skabende arkitekter......Artiklen fremhæver den visuelle rotation - billeder, tegninger, modeller, værker - som det privilligerede medium i kommunikationen af ideer imellem skabende arkitekter...
Spädtke, P
2013-01-01
Modeling of technical machines became a standard technique since computer became powerful enough to handle the amount of data relevant to the specific system. Simulation of an existing physical device requires the knowledge of all relevant quantities. Electric fields given by the surrounding boundary as well as magnetic fields caused by coils or permanent magnets have to be known. Internal sources for both fields are sometimes taken into account, such as space charge forces or the internal magnetic field of a moving bunch of charged particles. Used solver routines are briefly described and some bench-marking is shown to estimate necessary computing times for different problems. Different types of charged particle sources will be shown together with a suitable model to describe the physical model. Electron guns are covered as well as different ion sources (volume ion sources, laser ion sources, Penning ion sources, electron resonance ion sources, and H$^-$-sources) together with some remarks on beam transport.
This last volume in the series of textbooks on environmental isotopes in the hydrological cycle provides an overview of the basic principles of existing conceptual formulations of modelling approaches. While some of the concepts provided in Chapter 2 and Chapter 3 are of general validity for quantitative interpretation of isotope data; the modelling methodologies commonly employed for incorporating isotope data into evaluations specifically related to groundwater systems are given in this volume together with some illustrative examples. Development of conceptual models for quantitative interpretations of isotope data in hydrogeology and the assessment of their limitations and field verification has been given priority in the research and development efforts of the IAEA during the last decade. Several Co-ordinated Research Projects on this specific topic were implemented and results published by the IAEA. Based on these efforts and contributions made by a number of scientists involved in this specific field, the IAEA has published two Technical Documents entitled ''Mathematical models and their applications to isotope studies in groundwater studies -- IAEA TECDOC-777, 1994'' and ''Manual on Mathematical models in isotope hydrogeology -- IAEA TECDOC-910, 1996''. Results of a recently completed Co-ordinated Research Project by the IAEA entitled ''Use of isotopes for analysis of flow and transport dynamics in groundwater systems'' will also soon be published by the IAEA. This is the reason why the IAEA was involved in the co-ordination required for preparation of this volume; the material presented is a condensed overview prepared by some of the scientists that were involved in the above cited IAEA activities. This volume VI providing such an overview was included into the series to make this series self-sufficient in its coverage of the field of Isotope Hydrology. A special chapter on the methodologies and concepts related to geochemical modelling in groundwater
Variational approaches to the nuclear-matter problem: A progress report
The elements of state-independent Jastrow Fermi-hypermetted chain theory, of state-dependent variational theory, and of the method of correlated basis functions are surveyed. Results from application of these 'variational' approaches to popular homework potentials and to semi-realistic models of the nucleon-nucleon interaction are collected, and compared with recent results from Brueckner-Bethe theory. The crisis in nuclear-matter theory, brought on by gross discrepancies between earlier Brueckner-Bethe and variational calculations, has abated. (orig.)
Muller, Pierre-Alain; Fondement, Frédéric; Baudry, Benoit
2009-01-01
Model-driven engineering and model-based approaches have permeated all branches of software engineering; to the point that it seems that we are using models, as Molière's Monsieur Jourdain was using prose, without knowing it. At the heart of modeling, there is a relation that we establish to represent something by something else. In this paper we review various definitions of models and relations between them. Then, we define a canonical set of relations that can be used to express various ki...
On the nucleon momentum distribution in nuclei
A model of nuclear density ''coherentum fluctons'' (an alternative to Brueckner theory) is constructed with the aim of theoretically strict explanation of high moment components in nucleon momentum distribution that are responsible for the particle inclusive production. The formula of momentum distribution obtained within this model does not contain free parameters and high momentum components appear in a natural way
Muller, Pierre-Alain; Fondement, Frédéric; Baudry, Benoit; Combemale, Benoit
2012-01-01
Model-driven engineering and model-based approaches have permeated all branches of software engineering to the point that it seems that we are using models, as Molière's Monsieur Jourdain was using prose, without knowing it. At the heart of modeling, there is a relation that we establish to represent something by something else. In this paper we review various definitions of models and relations between them. Then, we define a canonical set of relations that can be used to express various kin...
Effects of Microscopic Three-body Forces in Asymmetric Nuclear Matter
无
2001-01-01
The efiects of microscopic three-body forces on the equatioil of state(EOS)and the single particle properties of isospin asymmetric nuclear matter have been studied within Brueckner-Hartree-Fock framework~[1]The microscopic three-body force model constructed from meson exchange current approach in Ref.~[2] has been extended to isospin asymmetric nuclear matter
Calculation of effective forces in nuclei from the Hamada- Johnston potential is described. This work begins from the theories of Brueckner and Bethe and applies them to finite systems. Various renormalizations of the force are discussed. The density dependence of the effective forces is considered in detail. Arguments for the partial breakdown of the shell model in heavy nuclei are given. (author)
Flavor Nuclei and One-Boson-Exchange Potentials
Bando, H.; Nagata, S.
1983-02-01
Binding energies of a flavour baryon, Λ(strange), Λc(charmed) and Λb(beauty), in nuclear matter and in the α-particle are investigated within the framework of the lowest-order Brueckner theory by employing the OBE potentials derived on the basis of the Nijmegen model D interaction.
Effective two nucleon (NN) interactions in the nuclear medium and for protons with energies in the range 65 to 200 MeV, have been defined from an accurate mapping of NN g matrices obtained by solving the Brueckner-Bethe-Goldstone (BBG) equations for infinite nuclear matter at various Fermi momenta to 1.5 fm-1. Then, by folding those effective interactions with the ground state one body (nucleon) density matrix elements (OBDME) of nuclei, we have defined proton-nucleus optical potentials. Those density matrix elements have been obtained with diverse (shell) models for the structure with very large basis space calculations used for light nuclei (to 28Si). The derived optical potentials are nonlocal, complex, and vary with energy and and have been used in the integro-differential form of the Schroedinger equation to predict differential cross sections, analyzing powers and, in some cases, spin rotations for elastic scattering. Excellent results have been obtained for many energies and for scattering from targets ranging from 4He to 208Pb and with but single shot calculations. Fits to the scattering date are very good when the ground state density matrix elements and single nucleon bound states are fixed by analyses of the form factors from elastic electron scattering. A key feature of our analysis method is that it is predictive. No adjustment of any element is made to improve fits to data. The relative motion wave functions that one finds with the nonlocal optical potentials then have been used as the distorted waves in distorted wave approximation (DWA) studies of select inelastic scattering events with light mass nuclei, in particular 12C and lithium isotopes. The same effective NN interactions were used as the transition operators in those calculations and the relevant nuclear spectroscopy (OBDME for inelastic scattering) have been found from large basis shell model evaluations of the nuclear structure; wave functions of which give good descriptions for many
On the Momentum Dependence of the Nucleon - Nucleus Optical Potential
Kleinmann, M.; Fritz, R.; Müther, H.; Ramos, A.
1994-01-01
The momentum dependence of the mean-field contribution to the real part of the optical model potential is investigated employing realistic nucleon-nucleon interactions. Within a non-relativistic approach a momentum dependence originates from the non-locality of the Fock exchange term. Deducing the real part of the optical model from a relativistic Dirac Brueckner Hartree Fock approximation for the self-energy of the nucleons yields an additional momentum dependence originating from the non-re...
Blouin A.; Combemale B.; Baudry B.; Beaudoux O.
2011-01-01
International audience Among model comprehension tools, model slicers are tools that extract a subset from a model, for a specific purpose. Model slicers are tools that let modelers rapidly gather relevant knowledge from large models. However, existing slicers are dedicated to one modeling language. This is an issue when we observe that new domain specific modeling languages (DSMLs), for which we want slicing abilities, are created almost on a daily basis. This paper proposes the Kompren l...
Hot neutron matter from a Self-Consistent Green's Functions approach
Rios, A; Vidaña, I
2008-01-01
A systematic study of the microscopic and thermodynamical properties of pure neutron matter at finite temperature within the Self-Consistent Green's Function approach is performed. The model dependence of these results is analyzed by both comparing the results obtained with two different microscopic interactions, the CD-BONN and the Argonne V18 potentials, and by analyzing the results obtained with other approaches, such as the Brueckner--Hartree--Fock approximation, the variational approach and the virial expansion.
Theory of Heavy Flavor in the Quark-Gluon Plasma
Rapp, Ralf
2011-01-01
Heavy-quark interactions in the Quark-Gluon Plasma are analyzed in terms of a selfconsistent Brueckner scheme using a thermodynamic $T$-matrix based on a potential model. The interrelations between quarkonium correlators, spectral functions and zero-modes, and open heavy-flavor transport and susceptibilities are elaborated. Independent constraints from thermal lattice QCD can be used to improve predictions for heavy-quark phenomenology in heavy-ion collisions.
Theory of Heavy Flavor in the Quark-Gluon Plasma
Rapp, Ralf [Cyclotron Institute and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843-3366 (United States)
2011-07-15
Heavy-quark interactions in the Quark-Gluon Plasma are analyzed in terms of a selfconsistent Brueckner scheme using a thermodynamic T-matrix based on a potential model. The interrelations between quarkonium correlators, spectral functions and zero-modes, and open heavy-flavor transport and susceptibilities are elaborated. Independent constraints from thermal lattice QCD can be used to improve predictions for heavy-quark phenomenology in heavy-ion collisions.
Theory of Heavy Flavor in the Quark-Gluon Plasma
Heavy-quark interactions in the Quark-Gluon Plasma are analyzed in terms of a selfconsistent Brueckner scheme using a thermodynamic T-matrix based on a potential model. The interrelations between quarkonium correlators, spectral functions and zero-modes, and open heavy-flavor transport and susceptibilities are elaborated. Independent constraints from thermal lattice QCD can be used to improve predictions for heavy-quark phenomenology in heavy-ion collisions.
Oscillations of hot, young neutron stars: Gravitational wave frequencies and damping times
Burgio, G.F.; Ferrari, V.; Gualtieri, L.; Schulze, H. J.
2011-01-01
We study how the frequencies and damping times of oscillations of a newly born, hot proto-neutron star depend on the physical quantities which characterize the star quasi-stationary evolution which follows the bounce. Stellar configurations are modeled using a microscopic equation of state obtained within the Brueckner-Hartree-Fock, nuclear many-body approach, extended to the finite-temperature regime. We discuss the mode frequency behaviour as function of the lepton composition, and of the e...
Pauli exclusion operator and binding energy of nuclear matter
Schiller, E.; Müther, H; Czerski, P.
1998-01-01
Brueckner-Hartree-Fock calculations are performed for nuclear matter with an exact treatment of the Pauli exclusion operator in the Bethe-Goldstone equation. The differences in the calculated binding energy, compared to the angle-average approximation, which is commonly used, are non-negligible. These difference exhibits a specific density dependence, which shifts the calculated saturation point towards smaller densities. This effect is observed for various versions of modern models for the N...
The Landau parameters of nuclear matter in relativistic Hartree approximation
The Landau parameters of nuclear matter have been calculated in relativistic Hartree approximation as a function of a renormalization scale. The results have then been compared to the empirical values deduced from constraints on isoscalar compression modes, spin-orbit splitting in nuclei and energy dependence of the nucleon-nucleus optical potential. For comparison, the results obtained for relativistic non-linear models and Dirac-Brueckner-Hartree-Fock calculations are also shown. (author)
Revisting the boiling of quark nuggets at nonzero chemical potential
Li, Ang; Liu, Tong; Gubler, Philipp; Xu, Ren-Xin
2013-01-01
The boiling of possible quark nuggets during the quark-hadron phase transition of the Universe at nonzero chemical potential is revisited within the microscopic Brueckner-Hartree-Fock approach employed for the hadron phase, using two kinds of baryon interactions as fundamental inputs. To describe the deconfined phase of quark matter, we use a recently developed quark mass density-dependent model with a fully self-consistent thermodynamic treatment of confinement. We study the baryon number li...
Pauli Exclusion Operator and Binding Energy of Nuclear Matter
Full text: Brueckner-Hartree-Fock calculations are performed for nuclear matter with an exact treatment of the Pauli exclusion operator in the Bethe-Goldstone equation. The differences in the calculated binding energy, compared to the angle-average approximation, which is commonly used, are non-negligible. These difference exhibits a specific density dependence, which shifts the calculated saturation point towards smaller densities. This effect is observed for various versions of modern models for the NN interaction. (author)
Microscopic in-medium nucleon-nucleon cross sections with improved Pauli blocking effects
B. Chen; Sammarruca, F.; Bertulani, C. A.
2013-01-01
We present updated predictions of effective elastic nucleon-nucleon cross sections intended for use in nucleus-nucleus reactions. A novel characteristic of the present approach combines all microscopic medium effects included in the Dirac-Brueckner-Hartree-Fock G-matrix with a Pauli blocking mechanism which is more appropriate for applications in ion-ion reaction models as compared to a previous approach. The effective in-medium cross section is found to be quite sensitive to the description ...
Mean field and collisions in hot nuclei
Collisions between heavy nuclei produce nuclear matter of high density and excitation. Brueckner methods are used to calculate the momentum and temperature dependent mean field for nucleons propagating through nuclear matter during these collisions. The mean field is complex and the imaginary part is related to the ''two-body'' collision, while the real part relates to ''one-body'' collisions. A potential model for the N-N interactions is avoided by calculating the Reaction matrix directly from the T-matrix (i.e., N-N phase shifts) using a version of Brueckner theory previously published by the author. Results are presented for nuclear matter at normal and twice normal density and for temperatures up to 50 MeV. 23 refs., 7 figs
Choice of single-particle potential and the convergence of the effective interaction
The convergence of the expansion for the effective interaction is studied considering as example the shell model for the nuclei 18O and 18F. In this work the effective interaction is computed through third order in the Brueckner G matrix, using both a harmonic-oscillator (HO) basis and a Brueckner-Hartree-Fock (BHF) basis. The significant differences in the convergence behavior of the effective interaction in these two cases are reported. The results indicate that the choice of the BHF single-particle potential facilitates the convergence of the effective interaction in low-orders of the expansion, whereas the HO results exhibit a non-convergent behavior. The implications for the HO approach are discussed. All calculations have been performed considering a modern version of the Bonn one-boson-exchange potential for the nucleon-nucleon interaction. 23 refs., 4 figs., 2 tabs
From nuclear matter to finite nuclei. Pt. 1
In this paper we develop various parametrizations of the nuclear matter Dirac-Brueckner G-matrix, which are suitable for application in relativistic Hartree-Fock calculations of finite nuclei. The relativistic one boson exchange model forms the basis of this effective interaction. The parameters, which are obtained from a least squares fit, explicitly depend on the density. We also require the interaction to reproduce the self-energies and the binding energy of nuclear matter very accurately. It is shown that for densities up to 1.5 times normal nuclear density the saturation curve virtually coincides with the original Dirac-Brueckner result and yields a good prediction of the nuclear matter compressibility. (orig.)
Onatski, Alexei; Williams, Noah
2003-01-01
Recently there has been much interest in studying monetary policy under model uncertainty. We develop methods to analyze different sources of uncertainty in one coherent structure useful for policy decisions. We show how to estimate the size of the uncertainty based on time series data, and incorporate this uncertainty in policy optimization. We propose two different approaches to modeling model uncertainty. The first is model error modeling, which imposes additional structure on the errors o...
Microscopic optical model potentials for p-nucleus scattering at intermediate energies
A comparative study of the microscopic optical potentials viz., semimicroscopic with extended Jeukenne-Lejeune-Mahaux interaction and microscopic Brueckner theory using Hamada-Johnston as well as Urbana V14 soft-core internucleon interactions, has been carried out. These microscopic optical potentials are compared with that of Dirac phenomenology (DP) for the polarized proton-40Ca elastic scattering at 35 MeV and 200 MeV. These potentials have different shapes for 200 MeV below 4 fm. In particular, for the real part of the central potential, only the Dirac phenomenology and the microscopic optical potential calculated with the Hamada-Johnston interaction exhibit the well known wine-bottle-bottom shape. It is found that the calculated observables (cross section, analyzing power and spin rotation function) using these potentials having different shapes, compare well with the experiment
Baden-Fuller, C.; Morgan, M S
2010-01-01
Drawing on research undertaken in the history and philosophy of science, with particular reference to the extensive literature which discusses the use of models in biology and economics, we explore the question ‘Are Business Models useful?’ We point out that they act as various forms of model: to provide means to describe and classify businesses; to operate as sites for scientific investigation; and to act as recipes for creative managers. We argue that studying business models as models is r...
Model Validation and Model Error Modeling
Ljung, Lennart
1999-01-01
To validate an estimated model and to have a good understanding of its reliability is a central aspect of System Identification. This contribution discusses these aspects in the light of model error models that are explicit descriptions of the model error. A model error model is implicitly present in most model validation methods, so the concept is more of a representation form than a set of new techniques. Traditional model validation is essentially a test of whether the confidence region of...
Nonlocal optical potentials for the scattering of 200 MeV protons from 22 nuclei, ranging in mass from 6Li to 208Pb, have been identified by folding a complex, medium dependent effective interaction with density matrix elements of each target. The effective interaction is based upon solutions of the Lippmann-Schwinger and Brueckner-Bethe-Goldstone equations having the paris potential as input. The bound state single particle wave functions that specify the nuclear density matrices are Woods-Saxon functions for A≤12 but harmonic oscillator functions thereafter. The Wood-Saxon potential parameters and harmonic oscillator lengths were determined from fits made to the elastic electron scattering form factors for the low mass nuclei (A≤ 20) and by finding our best fits to the proton scattering data for the nuclei of heavier mass. The resulting differential cross sections, analyzing powers and spin rotations all compare well with the known data. 38 refs., 2 tabs., 12 figs
Poulsen, Helle
1996-01-01
This paper presents a functional modelling method called Actant Modelling rooted in linguistics and semiotics. Actant modelling can be integrated with Multilevel Flow Modelling (MFM) in order to give an interpretation of actants.......This paper presents a functional modelling method called Actant Modelling rooted in linguistics and semiotics. Actant modelling can be integrated with Multilevel Flow Modelling (MFM) in order to give an interpretation of actants....
Anaïs Schaeffer
2012-01-01
By analysing the production of mesons in the forward region of LHC proton-proton collisions, the LHCf collaboration has provided key information needed to calibrate extremely high-energy cosmic ray models. Average transverse momentum (pT) as a function of rapidity loss ∆y. Black dots represent LHCf data and the red diamonds represent SPS experiment UA7 results. The predictions of hadronic interaction models are shown by open boxes (sibyll 2.1), open circles (qgsjet II-03) and open triangles (epos 1.99). Among these models, epos 1.99 shows the best overall agreement with the LHCf data. LHCf is dedicated to the measurement of neutral particles emitted at extremely small angles in the very forward region of LHC collisions. Two imaging calorimeters – Arm1 and Arm2 – take data 140 m either side of the ATLAS interaction point. “The physics goal of this type of analysis is to provide data for calibrating the hadron interaction models – the well-known &...
Cameron, Ian; Gani, Rafiqul
2011-01-01
This chapter deals with the practicalities of building, testing, deploying and maintaining models. It gives specific advice for each phase of the modelling cycle. To do this, a modelling framework is introduced which covers: problem and model definition; model conceptualization; model data...... requirements; model construction; model solution; model verification; model validation and finally model deployment and maintenance. Within the adopted methodology, each step is discussedthrough the consideration of key issues and questions relevant to the modelling activity. Practical advice, based on many...... years of experience is providing in directing the reader in their activities.Traps and pitfalls are discussed and strategies also given to improve model development towards “fit-for-purpose” models. The emphasis in this chapter is the adoption and exercise of a modelling methodology that has proven very...
Daniel J Kliebenstein
2012-01-01
Models of myriad forms are rapidly becoming central to biology. This ranges from statistical models that are fundamental to the interpretation of experimental results to ODE models that attempt to describe the results in a mechanistic format. Models will be more and more essential to biologists but this growing importance requires all model users to become more sophisticated about what is in a model and how that limits the usability of the model. This review attempts to relay the potential pi...
Li, Qin; Zhao, Yongxin; Wu, Xiaofeng; Liu, Si
There can be multitudinous models specifying aspects of the same system. Each model has a bias towards one aspect. These models often override in specific aspects though they have different expressions. A specification written in one model can be refined by introducing additional information from other models. The paper proposes a concept of promoting models which is a methodology to obtain refinements with support from cooperating models. It refines a primary model by integrating the information from a secondary model. The promotion principle is not merely an academic point, but also a reliable and robust engineering technique which can be used to develop software and hardware systems. It can also check the consistency between two specifications from different models. A case of modeling a simple online shopping system with the cooperation of the guarded design model and CSP model illustrates the practicability of the promotion principle.
Anyone who worries that physicists are running out of interesting challenges to tackle and important problems to solve should read the two, very different feature articles in this issue. In 'Climate change: complexity in action', Klaus Hasselmann and colleagues write about the challenges of including economic and political dimensions in computer simulations of climate change. It is hard to imagine a physics-based topic that has a greater impact on the world at large. In 'Quarks, diquarks and pentaquarks', Robert Jaffe and Frank Wilczek describe our current understanding of quantum chromodynamics and the strong nuclear force. In this case it is hard to think of many more difficult problems in fundamental physics. Traditional climate modelling is difficult enough because a whole range of effects in the atmosphere and the oceans have to be taken into account. It typically takes weeks for a state-of-the-art supercomputer to simulate 100 years of climate change with a horizontal resolution of 100 km. But climate change is about much more than solving difficult differential equations - there are crucial social, political and economic influences as well. Some researchers, including a significant number of physicists, have started to look at this integrated-assessment approach. The first challenge is to develop climate models that take minutes to run on a laptop. The next challenge is to develop analogous models that work in the social, political and economic arenas - which is not a trivial task - and then integrate all these different models and explore all the possible global-warming scenarios. Physicists also hope to integrate quantum chromodynamics (QCD) into the larger framework of a so-called theory of everything. Like climate modellers, particle theorists working on QCD require enormous computational resources for their calculations, and even then there are limits to what can be achieved (e.g. the mass of the proton has yet to be calculated from first principles
The equation of state at finite temperature: Structure and composition of protoneutron stars
Burgio, G. F.; Baldo, M.; Chen, H.; Schulze, H.-J.
2016-01-01
We study the hadron-quark phase transition at finite temperature in the interior of protoneutron stars, combining the equation of state obtained within the Brueckner-Hartree-Fock approach for hadronic matter with the MIT bag and the Dyson-Schwinger models for quark matter. We discuss the dependence of the results on different nuclear three-body forces and on details of the quark model. We find that a maximum mass exceeding two solar masses can be obtained with a strong three-body force and suitable parameter values in the Dyson-Schwinger model.
无
2003-01-01
This paper puts forward a new conception:model warehouse,analyzes the reason why model warehouse appears and introduces the characteristics and architecture of model warehouse.Last,this paper points out that model warehouse is an important part of WebGIS.
Sales-Cruz, Mauricio; Piccolo, Chiara; Heitzig, Martina;
2011-01-01
This chapter presents various types of constitutive models and their applications. There are 3 aspects dealt with in this chapter, namely: creation and solution of property models, the application of parameter estimation and finally application examples of constitutive models. A systematic...... procedure is introduced for the analysis and solution of property models. Models that capture and represent the temperature dependent behaviour of physical properties are introduced, as well as equation of state models (EOS) such as the SRK EOS. Modelling of liquid phase activity coefficients are also...... covered, illustrating several models such as the Wilson equation and NRTL equation, along with their solution strategies. A section shows how to use experimental data to regress the property model parameters using a least squares approach. A full model analysis is applied in each example that discusses...
Katerina Simons
1997-01-01
Modern finance would not have been possible without models. Increasingly complex quantitative models drive financial innovation and the growth of derivatives markets. Models are necessary to value financial instruments and to measure the risks of individual positions and portfolios. Yet when used inappropriately, the models themselves can become an important source of risk. Recently, several well-publicized instances occurred of institutions suffering significant losses attributed to model er...
M Batty
2007-01-01
The term ?model? is now central to our thinking about how weunderstand and design cities. We suggest a variety of ways inwhich we use ?models?, linking these ideas to Abercrombie?sexposition of Town and Country Planning which represented thestate of the art fifty years ago. Here we focus on using models asphysical representations of the city, tracing the development ofsymbolic models where the focus is on simulating how functiongenerates form, to iconic models where the focus is on representi...
Constraints on the quark matter equation of state from astrophysical observations
Burgio, G F; Schulze, H -J; Taranto, G
2013-01-01
We calculate the structure of neutron star interiors comprising both the hadronic and the quark phases. For the hadronic sector we employ a microscopic equation of state involving nucleons and hyperons derived within the Brueckner-Hartree-Fock many-body theory with realistic two-body and three-body forces. For the description of quark matter, we use several different models, e.g. the MIT bag, the Nambu--Jona-Lasinio (NJL), the Color Dielectric (CDM), the Field Correlator method (FCM), and one based on the Dyson-Schwinger model (DSM). We find that a two solar mass hybrid star is possible only if the nucleonic EOS is stiff enough.
Yost, S.A.
1991-05-01
Radom matrix models based on an integral over supermatrices are proposed as a natural extension of bosonic matrix models. The subtle nature of superspace integration allows these models to have very different properties from the analogous bosonic models. Two choices of integration slice are investigated. One leads to a perturbative structure which is reminiscent of, and perhaps identical to, the usual Hermitian matrix models. Another leads to an eigenvalue reduction which can be described by a two component plasma in one dimension. A stationary point of the model is described.
Larsen, Lars Bjørn; Vesterager, Johan
This report provides an overview of the existing models of global manufacturing, describes the required modelling views and associated methods and identifies tools, which can provide support for this modelling activity.The model adopted for global manufacturing is that of an extended enterprise....... One or more units from beyond the network may complement the extended enterprise. The common reference model for this extended enterprise will utilise GERAM (Generalised Enterprise Reference Architecture and Methodology) to provide an architectural framework for the modelling carried out within the...
Contributions to the workshop 'Geochemical modeling' from 19 to 20 September 1990 at the Karlsruhe Nuclear Research Centre. The report contains the programme and a selection of the lectures held at the workshop 'Geochemical modeling'. (BBR)
This presentation presented information on entrainment models. Entrainment models use entrainment hypotheses to express the continuity equation. The advantage is that plume boundaries are known. A major disadvantage is that the problems that can be solved are rather simple. The ...
Fox, Mark S.; Gruninger, Michael
1998-01-01
To remain competitive, enterprises must become increasingly agile and integrated across their functions. Enterprise models play a critical role in this integration, enabling better designs for enterprises, analysis of their performance, and management of their operations. This article motivates the need for enterprise models and introduces the concepts of generic and deductive enterprise models. It reviews research to date on enterprise modeling and considers in detail the Toronto virtual ent...
Jongerden, M.R.; Haverkort, B.R.
2008-01-01
The use of mobile devices is often limited by the capacity of the employed batteries. The battery lifetime determines how long one can use a device. Battery modeling can help to predict, and possibly extend this lifetime. Many different battery models have been developed over the years. However, with these models one can only compute lifetimes for specific discharge profiles, and not for workloads in general. In this paper, we give an overview of the different battery models that are availabl...
Turner, Raymond
2009-01-01
Computational models can be found everywhere in present day science and engineering. In providing a logical framework and foundation for the specification and design of specification languages, Raymond Turner uses this framework to introduce and study computable models. In doing so he presents the first systematic attempt to provide computational models with a logical foundation. Computable models have wide-ranging applications from programming language semantics and specification languages, through to knowledge representation languages and formalism for natural language semantics. They are al
Frampton, Paul H.
1997-01-01
In this talk I begin with some general discussion of model building in particle theory, emphasizing the need for motivation and testability. Three illustrative examples are then described. The first is the Left-Right model which provides an explanation for the chirality of quarks and leptons. The second is the 331-model which offers a first step to understanding the three generations of quarks and leptons. Third and last is the SU(15) model which can accommodate the light leptoquarks possibly...
In this work the most recent magnetospheric models are reviewed. After a short overview of the particle environment, a synthetic survey of the problem is given. For each feature of magnetospheric modelling (boundary, current sheet, ring-current) the approaches used by different authors are described. In the second part a description is given of the magnetospheric models, divided into four groups. In the last part, the different uses of magnetospheric models are illustrated by means of examples
Phoenix (formerly referred to as the Second Generation Model or SGM) is a global general equilibrium model designed to analyze energy-economy-climate related questions and policy implications in the medium- to long-term. This model disaggregates the global economy into 26 industr...
Sclütter, Flemming; Frigaard, Peter; Liu, Zhou
This report presents the model test results on wave run-up on the Zeebrugge breakwater under the simulated prototype storms. The model test was performed in January 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University. The detailed description of the model is given in...
Ravn, Anders P.; Staunstrup, Jørgen
1994-01-01
This paper proposes a model for specifying interfaces between concurrently executing modules of a computing system. The model does not prescribe a particular type of communication protocol and is aimed at describing interfaces between both software and hardware modules or a combination of the two....... The model describes both functional and timing properties of an interface...
Hydrological models are mediating models
Babel, L. V.; Karssenberg, D.
2013-08-01
Despite the increasing role of models in hydrological research and decision-making processes, only few accounts of the nature and function of models exist in hydrology. Earlier considerations have traditionally been conducted while making a clear distinction between physically-based and conceptual models. A new philosophical account, primarily based on the fields of physics and economics, transcends classes of models and scientific disciplines by considering models as "mediators" between theory and observations. The core of this approach lies in identifying models as (1) being only partially dependent on theory and observations, (2) integrating non-deductive elements in their construction, and (3) carrying the role of instruments of scientific enquiry about both theory and the world. The applicability of this approach to hydrology is evaluated in the present article. Three widely used hydrological models, each showing a different degree of apparent physicality, are confronted to the main characteristics of the "mediating models" concept. We argue that irrespective of their kind, hydrological models depend on both theory and observations, rather than merely on one of these two domains. Their construction is additionally involving a large number of miscellaneous, external ingredients, such as past experiences, model objectives, knowledge and preferences of the modeller, as well as hardware and software resources. We show that hydrological models convey the role of instruments in scientific practice by mediating between theory and the world. It results from these considerations that the traditional distinction between physically-based and conceptual models is necessarily too simplistic and refers at best to the stage at which theory and observations are steering model construction. The large variety of ingredients involved in model construction would deserve closer attention, for being rarely explicitly presented in peer-reviewed literature. We believe that devoting
Selén, Yngve
2004-01-01
Before using a parametric model one has to be sure that it offers a reasonable description of the system to be modeled. If a bad model structure is employed, the obtained model will also be bad, no matter how good is the parameter estimation method. There exist many possible ways of validating candidate models. This thesis focuses on one of the most common ways, i.e., the use of information criteria. First, some common information criteria are presented, and in the later chapters, various ext...
Stubkjær, Erik
2005-01-01
Modeling is a term that refers to a variety of efforts, including data and process modeling. The domain to be modeled may be a department, an organization, or even an industrial sector. E-business presupposes the modeling of an industrial sector, a substantial task. Cadastral modeling compares...... to the modeling of an industrial sector, as it aims at rendering the basic concepts that relate to the domain of real estate and the pertinent human activities. The palpable objects are pieces of land and buildings, documents, data stores and archives, as well as persons in their diverse roles as owners, holders...... to land. The paper advances the position that cadastral modeling has to include not only the physical objects, agents, and information sets of the domain, but also the objectives or requirements of cadastral systems....
Bois, Frederic Y; Brochot, Céline
2016-01-01
Pharmacokinetics is the study of the fate of xenobiotics in a living organism. Physiologically based pharmacokinetic (PBPK) models provide realistic descriptions of xenobiotics' absorption, distribution, metabolism, and excretion processes. They model the body as a set of homogeneous compartments representing organs, and their parameters refer to anatomical, physiological, biochemical, and physicochemical entities. They offer a quantitative mechanistic framework to understand and simulate the time-course of the concentration of a substance in various organs and body fluids. These models are well suited for performing extrapolations inherent to toxicology and pharmacology (e.g., between species or doses) and for integrating data obtained from various sources (e.g., in vitro or in vivo experiments, structure-activity models). In this chapter, we describe the practical development and basic use of a PBPK model from model building to model simulations, through implementation with an easily accessible free software. PMID:27311461
This lecture provides a survey of the methods used to model fast magnetosonic wave coupling, propagation, and absorption in tokamaks. The validity and limitations of three distinct types of modelling codes, which will be contrasted, include discrete models which utilize ray tracing techniques, approximate continuous field models based on a parabolic approximation of the wave equation, and full field models derived using finite difference techniques. Inclusion of mode conversion effects in these models and modification of the minority distribution function will also be discussed. The lecture will conclude with a presentation of time-dependent global transport simulations of ICRF-heated tokamak discharges obtained in conjunction with the ICRF modelling codes. 52 refs., 15 figs
Model choice versus model criticism
Robert, Christian P.; Mengersen, Kerrie; Chen, Carla
2009-01-01
The new perspectives on ABC and Bayesian model criticisms presented in Ratmann et al.(2009) are challenging standard approaches to Bayesian model choice. We discuss here some issues arising from the authors' approach, including prior influence, model assessment and criticism, and the meaning of error in ABC.
Correlations and spectral functions in asymmetric nuclear matter
The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realistic models for the nucleon-nucleon interaction. Starting from the Brueckner-Hartree-Fock approximation without the usual angle average in the two-nucleon propagator the effects of the hole-hole contributions are investigated within the self-consistent Green's function approach. Special attention is paid to the isospin dependence of correlations, which can be deduced from the spectral functions of nucleons in asymmetric matter. The strong components of the proton-neutron interaction lead in neutron-rich matter to a larger depletion for the occupation probability of proton states below the Fermi momentum
We describe our results for the calculated neutron-nucleus optical potential in the energy region 65-200 MeV for the scattering of neutrons from 40Ca, in first order Brueckner theory, using both the Urbana v -14 soft-core and Hamada - Johnston (HJ) hard-core interactions. The corresponding results are denoted by UB and HJ respectively. We have made a systematic study of energy dependence of Mean Square Radii and the volume integrals of the Optical model potentials. We have also used Hamada-Johnston realistic interaction for n- 40Ca in the energy region 65 to 225 MeV
Partial restoration of chiral symmetry in nuclear matter
Recent work of Cohen, Furnstahl, and Griegel has advanced our understanding of the behavior of quark and gluon condensates in nuclear matter. We make use of their analysis to discuss the role of chiral condensates as they appear in relativistic Brueckner-Hartree-Fock theory. We find some support for assumptions we used to discuss the properties of nuclear matter in our earlier work. We also find that a rather consistent picture emerges from these studies, when we relate the parameters of the boson-exchange model of nuclear forces to an underlying field-theoretic description of nuclear matter
H. Yang
1999-11-04
The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future.
Bækgaard, Lars
2001-01-01
The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics.We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...... temporarily from bookcases to borrowers. When we characterize events as change agents we focus on concepts like transactions, entity processes, and workflow processes....
Bækgaard, Lars
2001-01-01
The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics. We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...... temporarily from bookcases to borrowers. When we characterize events as change agents we focus on concepts like transactions, entity processes, and workflow processes....
This paper is an introduction course in modelling turbulent thermohydraulics, aimed at computational fluid dynamics users. No specific knowledge other than the Navier Stokes equations is required beforehand. Chapter I (which those who are not beginners can skip) provides basic ideas on turbulence physics and is taken up in a textbook prepared by the teaching team of the ENPC (Benque, Viollet). Chapter II describes turbulent viscosity type modelling and the 2k-ε two equations model. It provides details of the channel flow case and the boundary conditions. Chapter III describes the 'standard' (Rij-ε) Reynolds tensions transport model and introduces more recent models called 'feasible'. A second paper deals with heat transfer and the effects of gravity, and returns to the Reynolds stress transport model. (author)
Braby, L.A.
1990-09-01
The biological effects of ionizing radiation exposure are the result of a complex sequence of physical, chemical, biochemical, and physiological interactions. One way to begin a search for an understanding of health effects of radiation is through the development of phenomenological models of the response. Many models have been presented and tested in the slowly evolving process of characterizing cellular response. A range of models covering different endpoints and phenomena has developed in parallel. Many of these models employ similar assumptions about some underlying processes while differing about the nature of others. An attempt is made to organize many of the models into groups with similar features and to compare the consequences of those features with the actual experimental observations. It is assumed that by showing that some assumptions are inconsistent with experimental observations, the job of devising and testing mechanistic models can be simplified. 43 refs., 13 figs.
Nielsen, Mogens Peter; Shui, Wan; Johansson, Jens
2011-01-01
In this report a new turbulence model is presented.In contrast to the bulk of modern work, the model is a classical continuum model with a relatively simple constitutive equation. The constitutive equation is, as usual in continuum mechanics, entirely empirical. It has the usual Newton or Stokes...... term with stresses depending linearly on the strain rates. This term takes into account the transfer of linear momentum from one part of the fluid to another. Besides there is another term, which takes into account the transfer of angular momentum. Thus the model implies a new definition of turbulence....... The model is in a virgin state, but a number of numerical tests have been carried out with good results. It is published to encourage other researchers to study the model in order to find its merits and possible limitations....
Blomhøj, Morten
2004-01-01
Developing competences for setting up, analysing and criticising mathematical models are normally seen as relevant only from and above upper secondary level. The general belief among teachers is that modelling activities presuppose conceptual understanding of the mathematics involved. Mathematical...... modelling, however, can be seen as a practice of teaching that place the relation between real life and mathematics into the centre of teaching and learning mathematics, and this is relevant at all levels. Modelling activities may motivate the learning process and help the learner to establish cognitive...... roots for the construction of important mathematical concepts. In addition competences for setting up, analysing and criticising modelling processes and the possible use of models is a formative aim in this own right for mathematics teaching in general education. The paper presents a theoretical...
2016-01-01
This book provides a thorough introduction to the challenge of applying mathematics in real-world scenarios. Modelling tasks rarely involve well-defined categories, and they often require multidisciplinary input from mathematics, physics, computer sciences, or engineering. In keeping with this spirit of modelling, the book includes a wealth of cross-references between the chapters and frequently points to the real-world context. The book combines classical approaches to modelling with novel areas such as soft computing methods, inverse problems, and model uncertainty. Attention is also paid to the interaction between models, data and the use of mathematical software. The reader will find a broad selection of theoretical tools for practicing industrial mathematics, including the analysis of continuum models, probabilistic and discrete phenomena, and asymptotic and sensitivity analysis.
Sochůrková, Adéla
2012-01-01
The aim of this thesis is the compilation of an inventory management methods, describe their principles and assess the appropriateness of their use. In the introductory part of the work, "The nature and importance of inventory management" are briefly described the inventory management, the main objectives of inventory control models, the basic division of inventory species and costs of supply. The following chapter "Overview of inventory control models" includes a breakdown of models from dif...
Epstein, Joshua M.
2008-01-01
This address treats some enduring misconceptions about modeling. One of these is that the goal is always prediction. The lecture distinguishes between explanation and prediction as modeling goals, and offers sixteen reasons other than prediction to build a model. It also challenges the common assumption that scientific theories arise from and 'summarize' data, when often, theories precede and guide data collection; without theory, in other words, it is not clear what data to collect. Among ot...
Marco Antonio Moreira
1996-12-01
Full Text Available The mental models subject is presented particularly in the light of Johnson-Laird’s theory. Views from different authors are also presented but the emphasis lies in Johson-Laird’s approach, proposing mental models as a third path in the images x propositions debate. In this perspective, the nature, content, and typology of mental models are discussed, as well as the issue of conciousness and computability. In addition, the methodology of research studies are provided. Essentially, the aim of the paper is to provide an introduction to the mental models topic, having science education research in mind.
Liu, Zhou; Frigaard, Peter
This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University.......This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University....
Vestergaard, Kristian
engineers, but as the scale and the complexity of the hydraulic works increased, the mathematical models became so complex that a mathematical solution could not be obtained. This created a demand for new methods and again the experimental investigation became popular, but this time as measurements on small......-scale models. But still the scale and complexity of hydraulic works were increasing, and soon even small-scale models reached a natural limit for some applications. In the mean time the modern computer was developed, and it became possible to solve complex mathematical models by use of computer-based numerical...
The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post
Modeling Documents with Event Model
Longhui Wang
2015-08-01
Full Text Available Currently deep learning has made great breakthroughs in visual and speech processing, mainly because it draws lessons from the hierarchical mode that brain deals with images and speech. In the field of NLP, a topic model is one of the important ways for modeling documents. Topic models are built on a generative model that clearly does not match the way humans write. In this paper, we propose Event Model, which is unsupervised and based on the language processing mechanism of neurolinguistics, to model documents. In Event Model, documents are descriptions of concrete or abstract events seen, heard, or sensed by people and words are objects in the events. Event Model has two stages: word learning and dimensionality reduction. Word learning is to learn semantics of words based on deep learning. Dimensionality reduction is the process that representing a document as a low dimensional vector by a linear mode that is completely different from topic models. Event Model achieves state-of-the-art results on document retrieval tasks.
Poortman, Sybilla; Sloep, Peter
2006-01-01
Educational models describes a case study on a complex learning object. Possibilities are investigated for using this learning object, which is based on a particular educational model, outside of its original context. Furthermore, this study provides advice that might lead to an increase in teachers’ motivation for using and sharing learning objects. This document is aimed at teachers and educational designers.
Højgaard, Tomas; Hansen, Rune
2016-01-01
The purpose of this paper is to introduce Didactical Modelling as a research methodology in mathematics education. We compare the methodology with other approaches and argue that Didactical Modelling has its own specificity. We discuss the methodological “why” and explain why we find it useful to...
Jantzen, Jan
1998-01-01
A neural network can approximate a function, but it is impossible to interpret the result in terms of natural language. The fusion of neural networks and fuzzy logic in neurofuzzy models provide learning as well as readability. Control engineers find this useful, because the models can be...
Giandomenico, Rossano
2006-01-01
The model determines a stochastic continuous process as continuous limit of a stochastic discrete process so to show that the stochastic continuous process converges to the stochastic discrete process such that we can integrate it. Furthermore, the model determines the expected volatility and the expected mean so to show that the volatility and the mean are increasing function of the time.
Løssing, Ulrik
1986-01-01
Ulrik Løssing har redigeret, illustreret og oversat: "Scribe Modeller System, Sheffield, november 1985" af forfatterne: Cedric Green, David Cooper og John Wells.......Ulrik Løssing har redigeret, illustreret og oversat: "Scribe Modeller System, Sheffield, november 1985" af forfatterne: Cedric Green, David Cooper og John Wells....
Gøtze, Jens Peter; Krentz, Andrew
2014-01-01
In this issue of Cardiovascular Endocrinology, we are proud to present a broad and dedicated spectrum of reviews on animal models in cardiovascular disease. The reviews cover most aspects of animal models in science from basic differences and similarities between small animals and the human...
Kindler, Ekkart
2009-01-01
There are many different notations and formalisms for modelling business processes and workflows. These notations and formalisms have been introduced with different purposes and objectives. Later, influenced by other notations, comparisons with other tools, or by standardization efforts, these...... notations have been extended in order to increase expressiveness and to be more competitive. This resulted in an increasing number of notations and formalisms for modelling business processes and in an increase of the different modelling constructs provided by modelling notations, which makes it difficult...... to compare modelling notations and to make transformations between them. One of the reasons is that, in each notation, the new concepts are introduced in a different way by extending the already existing constructs. In this chapter, we go the opposite direction: We show that it is possible to add...
Building Models and Building Modelling
Jørgensen, Kaj Asbjørn; Skauge, Jørn
teoretiske basis for de kapitler, der har et mere teoretisk indhold. De følgende appendikser B-D indeholder nærmere karakteristika om de to modellerings CAD-programmer ArchiCAD og Architectural Desktop tillige med en sammenligning mellem de to værktøjer. I de resterende to appendikser beskrives de specielle...... problemstillinger vedrørende modellering af de to "Sorthøjparken"-modeller og de resulterende modeller bliver præsenteret og evalueret. Den samlede rapport er udgivet på projektets hjemmeside: www.iprod.aau.dk/bygit/Web3B/ under Technical Reports....
Veronica J. Rutledge
2013-01-01
The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of off-gas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data is obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data and parameters were input into the adsorption model to develop models specific for krypton adsorption. The same can be done for iodine, xenon, and tritium. The model will be validated with experimental breakthrough curves. Customers will be given access to
Kreiner, Svend; Christensen, Karl Bang
Rasch models; Partial Credit models; Rating Scale models; Item bias; Differential item functioning; Local independence; Graphical models......Rasch models; Partial Credit models; Rating Scale models; Item bias; Differential item functioning; Local independence; Graphical models...
Grimaldi, P.
2012-07-01
These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The The stereometric modelling means modelling achieved with : - the use of a pair of virtual cameras, with parallel axes and positioned at a mutual distance average of 1/10 of the distance camera-object (in practice the realization and use of a stereometric camera in the modeling program); - the shot visualization in two distinct windows - the stereoscopic viewing of the shot while modelling. Since the definition of "3D vision" is inaccurately referred to as the simple perspective of an object, it is required to add the word stereo so that "3D stereo vision " shall stand for "three-dimensional view" and ,therefore, measure the width, height and depth of the surveyed image. Thanks to the development of a stereo metric model , either real or virtual, through the "materialization", either real or virtual, of the optical-stereo metric model made visible with a stereoscope. It is feasible a continuous on line updating of the cultural heritage with the help of photogrammetry and stereometric modelling. The catalogue of the Architectonic Photogrammetry Laboratory of Politecnico di Bari is available on line at: http://rappresentazione.stereofot.it:591/StereoFot/FMPro?-db=StereoFot.fp5&-lay=Scheda&-format=cerca.htm&-view
Hodges, Wilfrid
1993-01-01
An up-to-date and integrated introduction to model theory, designed to be used for graduate courses (for students who are familiar with first-order logic), and as a reference for more experienced logicians and mathematicians.
Insepov, Zeke; Veitzer, Seth; Mahalingam, Sudhakar
2011-01-01
Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gra- dient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.
National Oceanic and Atmospheric Administration, Department of Commerce — Computer simulations of past climate. Variables provided as model output are described by parameter keyword. In some cases the parameter keywords are a subset of...
The author's goal is to provide a physical understanding of the ideal MHD model which includes: (1) a basic description of the model, (2) a derivation starting from a more fundamental kinetic model, and (3) a discussion of its range of validity. The ideal MHD model is a single-fluid model that describes the effects of magnetic geometry on the macroscopic equilibrium and stability properties of fusion plasmas. The model is derived in a straight forward manner by forming the mass, momentum, and energy moments of the Boltzmann equation. The moment equations reduce to ideal MHD with the introduction of three critical assumptions: high collisionality, small ion gyro radius, and small resistivity. An analysis of the validity conditions shows that the collision-dominated assumption is never satisfied in plasmas of fusion interest. The remaining two conditions are satisfied by a wide margin. A careful examination of the collision-dominated assumption shows that those particular parts of ideal MHD treated inaccurately (i.e., the parallel momentum and energy equations), play little, if any practical role in MHD equilibrium and stability. These equations primarily describe compression and expansion of a plasma whereas most MHD instabilities involve incompressible motions. The model is incorrect only where it does not matter. This realization leads to the introduction of a modified MHD model known as collisionless MHD which makes predictions nearly identical to collision-dominated assumption. It is thus valid for plasmas of fusion interest. The derivation follows from an analysis of single-particle guiding center motion in a collisionless plasma and the subsequent closure of the system by the heuristic assumption that the motions of interest are incompressible
Accelerated life models modeling and statistical analysis
Bagdonavicius, Vilijandas
2001-01-01
Failure Time DistributionsIntroductionParametric Classes of Failure Time DistributionsAccelerated Life ModelsIntroductionGeneralized Sedyakin's ModelAccelerated Failure Time ModelProportional Hazards ModelGeneralized Proportional Hazards ModelsGeneralized Additive and Additive-Multiplicative Hazards ModelsChanging Shape and Scale ModelsGeneralizationsModels Including Switch-Up and Cycling EffectsHeredity HypothesisSummaryAccelerated Degradation ModelsIntroductionDegradation ModelsModeling the Influence of Explanatory Varia
Kocherlakota, Narayana R.
2007-01-01
This paper uses an example to show that a model that fits the available data perfectly may provide worse answers to policy questions than an alternative, imperfectly fitting model. The author argues that, in the context of Bayesian estimation, this result can be interpreted as being due to the use of an inappropriate prior over the parameters of shock processes. He urges the use of priors that are obtained from explicit auxiliary information, not from the desire to obtain identification.
Model composition in model checking
Felscher, Ingo
2014-01-01
Model-checking allows one to formally check properties of systems: these properties are modeled as logic formulas and the systems as structures like transition systems. These transition systems are often composed, i.e., they arise in form of products or sums. The composition technique allows us to deduce the truth of a formula in the composed system from "interface information": the truth of formulas for the component systems and information in which components which of these formulas hold. W...
The invention relates to devices for modelling the space-dependent kinetics of a nuclear reactor. It can be advantageously used in studying the dynamics of the neutron field in the core to determine the effect of the control rods on the power distribution in the core, for training purposes. The proposed analog model of a nuclear reactor comprises operational amplifiers and a grid of resistors simulating neutron diffusion. Connected to the grid nodes are supply resistors modelling absorption and multiplication of neutrons. This is achieved by that, in the proposed model, all resistors through which power is supplied to the grid nodes are interconnected by their other leads and coupled to the output of the amplifier unit common for all nodes. Therewith, the amlifier unit models the transfer function of a ''point'' reactor. Connected to the input of this unit which includes two to four amplifiers are resistors for addition of signals with a grid node. Coupled to the grid nodes via additional resistors are voltage sources simulating reactivity
Nash, Ulrik William
2014-01-01
Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil......Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of...... probabilistic functionalism, and concerns the environment and the mind, and adaptation by the latter to the former. This entry is about the lens model, and probabilistic functionalism more broadly. Focus will mostly be on firms and their employees, but, to fully appreciate the scope, we have to keep in mind the...
2012-01-01
The relationship between representation and the represented is examined here through the notion of persistent modelling. This notion is not novel to the activity of architectural design if it is considered as describing a continued active and iterative engagement with design concerns – an evident...... characteristic of architectural practice. But the persistence in persistent modelling can also be understood to apply in other ways, reflecting and anticipating extended roles for representation. This book identifies three principle areas in which these extensions are becoming apparent within contemporary....... It also provides critical insight into the use of contemporary modelling tools and methods, together with an examination of the implications their use has within the territories of architectural design, realisation and experience....
Bork Petersen, Franziska
2013-01-01
focus centres on how the catwalk scenography evokes a ‘defiguration’ of the walking models and to what effect. Vibskov’s mobile catwalk draws attention to the walk, which is a key element of models’ performance but which usually functions in fashion shows merely to present clothes in the most...... advantageous manner. Stepping on the catwalk’s sloping, moving surfaces decelerates the models’ walk and makes it cautious, hesitant and shaky: suddenly the models lack exactly the affirmative, staccato, striving quality of motion, and the condescending expression that they perform on most contemporary...... determines the models’ walk. Furthermore, letting the models set off sound through triggers with attached sound samples gives them an implied agency. This calls into question the designer’s unrestricted authorship....
Ling Li; Vasily Volkov
2006-01-01
A physically-based model is presented for the simulation of a new type of deformable objects-inflatable objects, such as shaped balloons, which consist of pressurized air enclosed by an elastic surface. These objects have properties inherent in both 3D and 2D elastic bodies, as they demonstrate the behaviour of 3D shapes using 2D formulations. As there is no internal structure in them, their behaviour is substantially different from the behaviour of deformable solid objects. We use one of the few available models for deformable surfaces, and enhance it to include the forces of internal and external pressure. These pressure forces may also incorporate buoyancy forces, to allow objects filled with a low density gas to float in denser media. The obtained models demonstrate rich dynamic behaviour, such as bouncing, floating, deflation and inflation.
Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the 56Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed
Aarti Sharma
2009-01-01
Full Text Available The use of computational chemistry in the development of novel pharmaceuticals is becoming an increasingly important tool. In the past, drugs were simply screened for effectiveness. The recent advances in computing power and the exponential growth of the knowledge of protein structures have made it possible for organic compounds to be tailored to decrease the harmful side effects and increase the potency. This article provides a detailed description of the techniques employed in molecular modeling. Molecular modeling is a rapidly developing discipline, and has been supported by the dramatic improvements in computer hardware and software in recent years.
Arnoldi, Jakob
The article discusses the use of algorithmic models for so-called High Frequency Trading (HFT) in finance. HFT is controversial yet widespread in modern financial markets. It is a form of automated trading technology which critics among other things claim can lead to market manipulation. Drawing on...... two cases, this article shows that manipulation more likely happens in the reverse way, meaning that human traders attempt to make algorithms ‘make mistakes’ or ‘mislead’ algos. Thus, it is algorithmic models, not humans, that are manipulated. Such manipulation poses challenges for security exchanges...
Cardey, Sylviane
2013-01-01
In response to the need for reliable results from natural language processing, this book presents an original way of decomposing a language(s) in a microscopic manner by means of intra/inter‑language norms and divergences, going progressively from languages as systems to the linguistic, mathematical and computational models, which being based on a constructive approach are inherently traceable. Languages are described with their elements aggregating or repelling each other to form viable interrelated micro‑systems. The abstract model, which contrary to the current state of the art works in int
Sivaram, C.
2007-01-01
An alternate model for gamma ray bursts is suggested. For a white dwarf (WD) and neutron star (NS) very close binary system, the WD (close to Mch) can detonate due to tidal heating, leading to a SN. Material falling on to the NS at relativistic velocities can cause its collapse to a magnetar or quark star or black hole leading to a GRB. As the material smashes on to the NS, it is dubbed the Smashnova model. Here the SN is followed by a GRB. NS impacting a RG (or RSG) (like in Thorne-Zytkow ob...
Holmes, Jon L.
1999-06-01
Molecular modeling has trickled down from the realm of pharmaceutical and research laboratories into the realm of undergraduate chemistry instruction. It has opened avenues for the visualization of chemical concepts that previously were difficult or impossible to convey. I am sure that many of you have developed exercises using the various molecular modeling tools. It is the desire of this Journal to become an avenue for you to share these exercises among your colleagues. It is to this end that Ron Starkey has agreed to edit such a column and to publish not only the description of such exercises, but also the software documents they use. The WWW is the obvious medium to distribute this combination and so accepted submissions will appear online as a feature of JCE Internet. Typical molecular modeling exercise: finding conformation energies. Molecular Modeling Exercises and Experiments is the latest feature column of JCE Internet, joining Conceptual Questions and Challenge Problems, Hal's Picks, and Mathcad in the Chemistry Curriculum. JCE Internet continues to seek submissions in these areas of interest and submissions of general interest. If you have developed materials and would like to submit them, please see our Guide to Submissions for more information. The Chemical Education Resource Shelf, Equipment Buyers Guide, and WWW Site Review would also like to hear about chemistry textbooks and software, equipment, and WWW sites, respectively. Please consult JCE Internet Features to learn more about these resources at JCE Online. Email Announcements Would you like to be informed by email when the latest issue of the Journal is available online? when a new JCE Software title is shipping? when a new JCE Internet article has been published or is available for Open Review? when your subscription is about to expire? A new feature of JCE Online makes this possible. Visit our Guestbook to learn how. When you submit the form on this page, which includes your email address
Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK)
Michael, John
others' minds. Then (2), in order to bring to light some possible justifications, as well as hazards and criticisms of the methodology of looking time tests, I will take a closer look at the concept of folk psychology and will focus on the idea that folk psychology involves using oneself as a model of...
Olaf eWolkenhauer
2014-01-01
Full Text Available Next generation sequencing technologies are bringing about a renaissance of mining approaches. A comprehensive picture of the genetic landscape of an individual patient will be useful, for example, to identify groups of patients that do or do not respond to certain therapies. The high expectations may however not be satisfied if the number of patient groups with similar characteristics is going to be very large. I therefore doubt that mining sequence data will give us an understanding of why and when therapies work. For understanding the mechanisms underlying diseases, an alternative approach is to model small networks in quantitative mechanistic detail, to elucidate the role of gene and proteins in dynamically changing the functioning of cells. Here an obvious critique is that these models consider too few components, compared to what might be relevant for any particular cell function. I show here that mining approaches and dynamical systems theory are two ends of a spectrum of methodologies to choose from. Drawing upon personal experience in numerous interdisciplinary collaborations, I provide guidance on how to model by discussing the question Why model?
Baart, F.; Donchyts, G.; van Dam, A.; Plieger, M.
2015-12-01
The emergence of interactive art has blurred the line between electronic, computer graphics and art. Here we apply this art form to numerical models. Here we show how the transformation of a numerical model into an interactive painting can both provide insights and solve real world problems. The cases that are used as an example include forensic reconstructions, dredging optimization, barrier design. The system can be fed using any source of time varying vector fields, such as hydrodynamic models. The cases used here, the Indian Ocean (HYCOM), the Wadden Sea (Delft3D Curvilinear), San Francisco Bay (3Di subgrid and Delft3D Flexible Mesh), show that the method used is suitable for different time and spatial scales. High resolution numerical models become interactive paintings by exchanging their velocity fields with a high resolution (>=1M cells) image based flow visualization that runs in a html5 compatible web browser. The image based flow visualization combines three images into a new image: the current image, a drawing, and a uv + mask field. The advection scheme that computes the resultant image is executed in the graphics card using WebGL, allowing for 1M grid cells at 60Hz performance on mediocre graphic cards. The software is provided as open source software. By using different sources for a drawing one can gain insight into several aspects of the velocity fields. These aspects include not only the commonly represented magnitude and direction, but also divergence, topology and turbulence .
Taylor, Julie
2013-01-01
This paper provides a brief overview of the NSPCC/University of Edinburgh Child Protection Research Centre. It highlights the Centre's work, approach, progress to date and direction of travel. The document includes the Centre's Logic Model which details types of research and outcomes.
R.E. Waltz
2007-01-01
@@ There has been remarkable progress during the past decade in understanding and modeling turbulent transport in tokamaks. With some exceptions the progress is derived from the huge increases in computational power and the ability to simulate tokamak turbulence with ever more fundamental and physically realistic dynamical equations, e.g.
Burianová, Eva
2008-01-01
Cílem první části této bakalářské práce je - pomocí analýzy výchozích textů - teoretické shrnutí ekonomických modelů a teorií, na kterých model CAPM stojí: Markowitzův model teorie portfolia (analýza maximalizace očekávaného užitku a na něm založený model výběru optimálního portfolia), Tobina (rozšíření Markowitzova modelu ? rozdělení výběru optimálního portfolia do dvou fází; nejprve určení optimální kombinace rizikových instrumentů a následná alokace dostupného kapitálu mezi tuto optimální ...
Jensen, Morten S.; Frigaard, Peter
In the following, results from model tests with Zeebrugge breakwater are presented. The objective with these tests is partly to investigate the influence on wave run-up due to a changing waterlevel during a storm. Finally, the influence on wave run-up due to an introduced longshore current is...
N. Bosma (Niels); G. de Wit (Gerrit); M.A. Carree (Martin)
2003-01-01
textabstractTwo approaches can be distinguished with respect to modelling entrepreneurship: (i) the approach focusing on the net development of the number of entrepreneurs in an equilibrium framework and (ii) the approach focusing on the entries and exits of entrepreneurs. In this paper we unify the
The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of this analysis is to document the criticality computational method. The criticality
A. Alsaed
2004-09-14
The ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003) presents the methodology for evaluating potential criticality situations in the monitored geologic repository. As stated in the referenced Topical Report, the detailed methodology for performing the disposal criticality analyses will be documented in model reports. Many of the models developed in support of the Topical Report differ from the definition of models as given in the Office of Civilian Radioactive Waste Management procedure AP-SIII.10Q, ''Models'', in that they are procedural, rather than mathematical. These model reports document the detailed methodology necessary to implement the approach presented in the Disposal Criticality Analysis Methodology Topical Report and provide calculations utilizing the methodology. Thus, the governing procedure for this type of report is AP-3.12Q, ''Design Calculations and Analyses''. The ''Criticality Model'' is of this latter type, providing a process evaluating the criticality potential of in-package and external configurations. The purpose of this analysis is to layout the process for calculating the criticality potential for various in-package and external configurations and to calculate lower-bound tolerance limit (LBTL) values and determine range of applicability (ROA) parameters. The LBTL calculations and the ROA determinations are performed using selected benchmark experiments that are applicable to various waste forms and various in-package and external configurations. The waste forms considered in this calculation are pressurized water reactor (PWR), boiling water reactor (BWR), Fast Flux Test Facility (FFTF), Training Research Isotope General Atomic (TRIGA), Enrico Fermi, Shippingport pressurized water reactor, Shippingport light water breeder reactor (LWBR), N-Reactor, Melt and Dilute, and Fort Saint Vrain Reactor spent nuclear fuel (SNF). The scope of
Information Model for Product Modeling
焦国方; 刘慎权
1992-01-01
The Key problems in product modeling for integrated CAD ∥CAM systems are the information structures and representations of products.They are taking more and more important roles in engineering applications.With the investigation on engineering product information and from the viewpoint of industrial process,in this paper,the information models are proposed and the definitions of the framework of product information are given.And then,the integration and the consistence of product information are discussed by introucing the entity and its instance.As a summary,the information structures described in this paper have many advantage and natures helpful in engineering design.
Aarti Sharma
2009-12-01
Full Text Available
Almeida, Leandro S.; José Fernando A. Cruz; Ferreira, Helena Isabel dos Santos Ribeiro; Pinto, Alberto
2011-01-01
The Theory of Planned Behavior studies the decision-making mechanisms of individuals. We propose the Nash Equilibria as one, of many, possible mechanisms of transforming human intentions in behavior. This process corresponds to the best strategic individual decision taking in account the collective response. We built a game theoretical model to understand the role of leaders in decision-making of individuals or groups. We study the characteristics of the leaders that can have a...
Clyde, Merlise; George, Edward I.
2004-01-01
The evolution of Bayesian approaches for model uncertainty over the past decade has been remarkable. Catalyzed by advances in methods and technology for posterior computation, the scope of these methods has widened substantially. Major thrusts of these developments have included new methods for semiautomatic prior specification and posterior exploration. To illustrate key aspects of this evolution, the highlights of some of these developments are described.
This lecture was given at the KEK Summer School on August 3-6, 1993 by Professor N. Sakai. All the available experimental data at low energy can be adequately described by the standard model with SU(3) x SU(2) x U(1) gauge group. The three different gauge coupling constants originate from the three different interactions, namely, strong, weak and electromagnetic interactions. The three interactions described by the three different gauge groups can be truly unified into a single gauge group if a simple gauge group to describe all three interactions is chosen. Even if the grand unified theory is not accepted, the existence of gravitational interaction is sure. There are only two options to explain the gauge hierarchy, that is, technicolor model and supersymmetry. As the introduction to supersymmetry, Spinors and Grassmann number, Supertransformation, unitary representation, chiral scalar superfield and supersymmetric Lagrangian field theory are explained. Regarding the supersymmetric SU(3) x SU(2) x U(1) model, Yukawa coupling and particle content are described. It should be noted that the Higgsino (chiral fermions associated with Higgs scalar) in general introduces anomaly in gauge currents. The simplest way out of such anomaly problem is to introduce Higgsino doublet in pair. (K.I.)
Plimpton, Steven James; Heffernan, Julieanne; Sasaki, Darryl Yoshio; Frischknecht, Amalie Lucile; Stevens, Mark Jackson; Frink, Laura J. Douglas
2005-11-01
Understanding the properties and behavior of biomembranes is fundamental to many biological processes and technologies. Microdomains in biomembranes or ''lipid rafts'' are now known to be an integral part of cell signaling, vesicle formation, fusion processes, protein trafficking, and viral and toxin infection processes. Understanding how microdomains form, how they depend on membrane constituents, and how they act not only has biological implications, but also will impact Sandia's effort in development of membranes that structurally adapt to their environment in a controlled manner. To provide such understanding, we created physically-based models of biomembranes. Molecular dynamics (MD) simulations and classical density functional theory (DFT) calculations using these models were applied to phenomena such as microdomain formation, membrane fusion, pattern formation, and protein insertion. Because lipid dynamics and self-organization in membranes occur on length and time scales beyond atomistic MD, we used coarse-grained models of double tail lipid molecules that spontaneously self-assemble into bilayers. DFT provided equilibrium information on membrane structure. Experimental work was performed to further help elucidate the fundamental membrane organization principles.
Exhaust gases from power plants that burn fossil fuels contain concentrations of sulfur dioxide (SO2), nitric oxide (NO), particulate matter, hydrocarbon compounds and trace metals. Estimated emissions from the operation of a hypothetical 500 MW coal-fired power plant are given. Ozone is considered a secondary pollutant, since it is not emitted directly into the atmosphere but is formed from other air pollutants, specifically, nitrogen oxides (NO), and non-methane organic compounds (NMOQ) in the presence of sunlight. (NMOC are sometimes referred to as hydrocarbons, HC, or volatile organic compounds, VOC, and they may or may not include methane). Additionally, ozone formation Alternative is a function of the ratio of NMOC concentrations to NOx concentrations. A typical ozone isopleth is shown, generated with the Empirical Kinetic Modeling Approach (EKMA) option of the Environmental Protection Agency's (EPA) Ozone Isopleth Plotting Mechanism (OZIPM-4) model. Ozone isopleth diagrams, originally generated with smog chamber data, are more commonly generated with photochemical reaction mechanisms and tested against smog chamber data. The shape of the isopleth curves is a function of the region (i.e. background conditions) where ozone concentrations are simulated. The location of an ozone concentration on the isopleth diagram is defined by the ratio of NMOC and NOx coordinates of the point, known as the NMOC/NOx ratio. Results obtained by the described model are presented
Technological Forecasting---Model Selection, Model Stability, and Combining Models
Nigel Meade; Towhidul Islam
1998-01-01
The paper identifies 29 models that the literature suggests are appropriate for technological forecasting. These models are divided into three classes according to the timing of the point of inflexion in the innovation or substitution process. Faced with a given data set and such a choice, the issue of model selection needs to be addressed. Evidence used to aid model selection is drawn from measures of model fit and model stability. An analysis of the forecasting performance of these models u...
Model Construct Based Enterprise Model Architecture and Its Modeling Approach
无
2002-01-01
In order to support enterprise integration, a kind of model construct based enterprise model architecture and its modeling approach are studied in this paper. First, the structural makeup and internal relationships of enterprise model architecture are discussed. Then, the concept of reusable model construct (MC) which belongs to the control view and can help to derive other views is proposed. The modeling approach based on model construct consists of three steps, reference model architecture synthesis, enterprise model customization, system design and implementation. According to MC based modeling approach a case study with the background of one-kind-product machinery manufacturing enterprises is illustrated. It is shown that proposal model construct based enterprise model architecture and modeling approach are practical and efficient.
Unnikrishnan, A.S.; Manoj, N.T.
the wetted perimeter and A the area of cross section (excluding mud flats); C = (1.49/n)R1/6, where n is the Manning coefficient. The numerical scheme used by Harleman and Lee (1969) was used to solve the above equations. In this scheme, the continuity... equation is solved at odd grid points to compute eta at the next time step and the momentum equation is solved at even grid points to compute U . The original scheme of Harleman & Lee (1969) was developed for a single channel. For developing a model...
Liu Zhiyang
2011-01-01
Similar to ISO Technical Committees,SAC Technical Committees undertake the management and coordination of standard's development and amendments in various sectors in industry,playing the role as a bridge among enterprises,research institutions and the governmental standardization administration.How to fully play the essential role is the vital issue SAC has been committing to resolve.Among hundreds of SAC TCs,one stands out in knitting together those isolated,scattered,but highly competitive enterprises in the same industry with the "Standards" thread,and achieving remarkable results in promoting industry development with standardization.It sets a role model for other TCs.
From model checking to model measuring
Henzinger, Thomas A.; Otop, Jan
2013-01-01
We define the model-measuring problem: given a model $M$ and specification~$\\varphi$, what is the maximal distance $\\rho$ such that all models $M'$ within distance $\\rho$ from $M$ satisfy (or violate)~$\\varphi$. The model measuring problem presupposes a distance function on models. We concentrate on automatic distance functions, which are defined by weighted automata. The model-measuring problem subsumes several generalizations of the classical model-checking problem, in particular, qu...
ModelWizard: Toward Interactive Model Construction
Hutchison, Dylan
2016-01-01
Data scientists engage in model construction to discover machine learning models that well explain a dataset, in terms of predictiveness, understandability and generalization across domains. Questions such as "what if we model common cause Z" and "what if Y's dependence on X reverses" inspire many candidate models to consider and compare, yet current tools emphasize constructing a final model all at once. To more naturally reflect exploration when debating numerous models, we propose an inter...
Towards a Multi Business Model Innovation Model
Lindgren, Peter; Jørgensen, Rasmus
2012-01-01
This paper studies the evolution of business model (BM) innovations related to a multi business model framework. The paper tries to answer the research questions: • What are the requirements for a multi business model innovation model (BMIM)? • How should a multi business model innovation model...... look like? Different generations of BMIMs are initially studied in the context of laying the baseline for how next generation multi BM Innovation model (BMIM) should look like. All generations of models are analyzed with the purpose of comparing the characteristics and challenges of previous...
Better Language Models with Model Merging
Brants, T
1996-01-01
This paper investigates model merging, a technique for deriving Markov models from text or speech corpora. Models are derived by starting with a large and specific model and by successively combining states to build smaller and more general models. We present methods to reduce the time complexity of the algorithm and report on experiments on deriving language models for a speech recognition task. The experiments show the advantage of model merging over the standard bigram approach. The merged model assigns a lower perplexity to the test set and uses considerably fewer states.
Impedance model for nanostructures
R. S. Akhmedov
2007-06-01
Full Text Available The application of the impedance model for nanoelectronic quantum-mechanical structures modelling is described. Characteristics illustrating the efficiency of the model are presented.
Building Mental Models by Dissecting Physical Models
Srivastava, Anveshna
2016-01-01
When students build physical models from prefabricated components to learn about model systems, there is an implicit trade-off between the physical degrees of freedom in building the model and the intensity of instructor supervision needed. Models that are too flexible, permitting multiple possible constructions require greater supervision to…
From Product Models to Product State Models
Larsen, Michael Holm
1999-01-01
A well-known technology designed to handle product data is Product Models. Product Models are in their current form not able to handle all types of product state information. Hence, the concept of a Product State Model (PSM) is proposed. The PSM and in particular how to model a PSM is the Research...
The IMACLIM model; Le modele IMACLIM
NONE
2003-07-01
This document provides annexes to the IMACLIM model which propose an actualized description of IMACLIM, model allowing the design of an evaluation tool of the greenhouse gases reduction policies. The model is described in a version coupled with the POLES, technical and economical model of the energy industry. Notations, equations, sources, processing and specifications are proposed and detailed. (A.L.B.)
Rask, Morten
insight from the literature about business models, international product policy, international entry modes and globalization into a conceptual model of relevant design elements of global business models, enabling global business model innovation to deal with differences in a downstream perspective...
Forward model nonlinearity versus inverse model nonlinearity
Mehl, S.
2007-01-01
The issue of concern is the impact of forward model nonlinearity on the nonlinearity of the inverse model. The question posed is, "Does increased nonlinearity in the head solution (forward model) always result in increased nonlinearity in the inverse solution (estimation of hydraulic conductivity)?" It is shown that the two nonlinearities are separate, and it is not universally true that increased forward model nonlinearity increases inverse model nonlinearity. ?? 2007 National Ground Water Association.
Combemale, Benoit; Cheng, Betty H.C.; Moreira, Ana; Bruel, Jean-Michel; Gray, Jeff
2015-01-01
Various disciplines use models for different purposes. An engineering model, including a software engineering model, is often developed to guide the construction of a non-existent system. A scientific model is created to better understand a natural phenomenon (i.e., an already existing system). An engineering model may incorporate scientific models to build a system. Sustainability is an area that requires both types of models. Both engineering and scientific models have been used to support ...
A review is made of some properties of the rotating Universe models. Godel's model is identified as a generalized filted model. Some properties of new solutions of the Einstein's equations, which are rotating non-stationary Universe models, are presented and analyzed. These models have the Godel's model as a particular case. Non-stationary cosmological models are found which are a generalization of the Godel's metrics in an analogous way in which Friedmann is to the Einstein's model. (L.C.)
Concept Modeling vs. Data modeling in Practice
Madsen, Bodil Nistrup; Erdman Thomsen, Hanne
2015-01-01
This chapter shows the usefulness of terminological concept modeling as a first step in data modeling. First, we introduce terminological concept modeling with terminological ontologies, i.e. concept systems enriched with characteristics modeled as feature specifications. This enables a formal...... account of the inheritance of characteristics and allows us to introduce a number of principles and constraints which render concept modeling more coherent than earlier approaches. Second, we explain how terminological ontologies can be used as the basis for developing conceptual and logical data models....... We also show how to map from the various elements in the terminological ontology to elements in the data models, and explain the differences between the models. Finally the usefulness of terminological ontologies as a prerequisite for IT development and data modeling is illustrated with examples from...
Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik
1997-01-01
This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application of the l......This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...
Ab initio calculation of the lifetimes of 4p and 3d levels of Ca+
We have done an ab initio calculation based on the Brueckner approximation for the lifetimes of 4p2P and 3d2D levels of Ca+. The results of the Brueckner approximation differ from experiment by 2.5%. With leading third-order corrections included, our results agree with the latest accurate experiment within a 1% difference
Optimal predictive model selection
Barbieri, Maria Maddalena; Berger, James O.
2004-01-01
Often the goal of model selection is to choose a model for future prediction, and it is natural to measure the accuracy of a future prediction by squared error loss. Under the Bayesian approach, it is commonly perceived that the optimal predictive model is the model with highest posterior probability, but this is not necessarily the case. In this paper we show that, for selection among normal linear models, the optimal predictive model is often the median probability model, which is defined a...
Dodgson, Mark; Gann, David; Phillips, Nelson; Massa, Lorenzo; Tucci, Christopher
2014-01-01
The chapter offers a broad review of the literature at the nexus between Business Models and innovation studies, and examines the notion of Business Model Innovation in three different situations: Business Model Design in newly formed organizations, Business Model Reconfiguration in incumbent firms, and Business Model Innovation in the broad context of sustainability. Tools and perspectives to make sense of Business Models and support managers and entrepreneurs in dealing with Business Model ...
Wake modelling combining mesoscale and microscale models
Badger, Jake; Volker, Patrick; Prospathospoulos, J.; Sieros, G.; Ott, Søren; Réthoré, Pierre-Elouan; Hahmann, Andrea N.; Hasager, Charlotte Bay
2013-01-01
In this paper the basis for introducing thrust information from microscale wake models into mesocale model wake parameterizations will be described. A classification system for the different types of mesoscale wake parameterizations is suggested and outlined. Four different mesoscale wake...
Model Manipulation for End-User Modelers
Acretoaie, Vlad
, and transformations using their modeling notation and editor of choice. The VM* languages are implemented via a single execution engine, the VM* Runtime, built on top of the Henshin graph-based transformation engine. This approach combines the benefits of flexibility, maturity, and formality. To simplify model editor......End-user modelers are domain experts who create and use models as part of their work. They are typically not Software Engineers, and have little or no programming and meta-modeling experience. However, using model manipulation languages developed in the context of Model-Driven Engineering often...... requires such experience. These languages are therefore only used by a small subset of the modelers that could, in theory, benefit from them. The goals of this thesis are to substantiate this observation, introduce the concepts and tools required to overcome it, and provide empirical evidence in support...
Model Checking of Boolean Process Models
Schneider, Christoph; Wehler, Joachim
2011-01-01
In the field of Business Process Management formal models for the control flow of business processes have been designed since more than 15 years. Which methods are best suited to verify the bulk of these models? The first step is to select a formal language which fixes the semantics of the models. We adopt the language of Boolean systems as reference language for Boolean process models. Boolean systems form a simple subclass of coloured Petri nets. Their characteristics are low tokens to mode...
MODEL VALIDATION AND THE PHILIPPINE PROGRAMMING MODEL
Rodriguez, Gil R. Jr.; Kunkel, David E.
1980-01-01
This research demonstrates the need and the procedure for testing sector programming models It compares the model estimates of endogenous variables to carefully selected base period parameters It uses an operational, static, deterministic, and highly aggregate programming model of Philippine agriculture as the framework Alternative formulations of the Philippine model are also examined for possible errors In the consumption, production, and objective function data sets
Molecular Models: Construction of Models with Magnets
Kalinovčić P.
2015-01-01
Molecular models are indispensable tools in teaching chemistry. Beside their high price, commercially available models are generally too small for classroom demonstration. This paper suggests how to make space-filling (callote) models from Styrofoam with magnetic balls as connectors and disc magnets for showing molecular polarity
Tahir Abdullah
2012-02-01
Full Text Available Software architecture design and requirement engineering are core and independent areas of engineering. A lot of research, education and practice are carried on Requirement elicitation and doing refine it, but it is a major issue of engineering. QSMSR model act as a bridge between requirement and design there is a huge gap between these two areas of software architecture and requirement engineering. The QSMSR model divide into two sub model qualitative model and Principal model in this research we focus on Qualitative model which further divide into two sub models fabricated model and classified model. Classified model make the sub groups of the role and match it with components. The Fabricated model link QSMSR Principal Model to an architecture design. At the end it provides the QSMSR Architecture model of the system as output.
Willden, Jeff
2001-01-01
"Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…
Könemann, Patrick
just contain a list of strings, one for each line, whereas the structure of models is defined by their meta models. There are tools available which are able to compute the diff between two models, e.g. RSA or EMF Compare. However, their diff is not model-independent, i.e. it refers to the models it was...
Automated data model evaluation
Modeling process is essential phase within information systems development and implementation. This paper presents methods and techniques for analysis and evaluation of data model correctness. Recent methodologies and development results regarding automation of the process of model correctness analysis and relations with ontology tools has been presented. Key words: Database modeling, Data model correctness, Evaluation
Modelling Foundations and Applications
selected from 81 submissions. Papers on all aspects of MDE were received, including topics such as architectural modelling and product lines, code generation, domain-specic modeling, metamodeling, model analysis and verication, model management, model transformation and simulation. The breadth of topics...
Environmental Satellite Models for a Macroeconomic Model
To support national environmental policy, it is desirable to forecast and analyse environmental indicators consistently with economic variables. However, environmental indicators are physical measures linked to physical activities that are not specified in economic models. One way to deal with this is to develop environmental satellite models linked to economic models. The system of models presented gives a frame of reference where emissions of greenhouse gases, acid gases, and leaching of nutrients to the aquatic environment are analysed in line with - and consistently with - macroeconomic variables. This paper gives an overview of the data and the satellite models. Finally, the results of applying the model system to calculate the impacts on emissions and the economy are reviewed in a few illustrative examples. The models have been developed for Denmark; however, most of the environmental data used are from the CORINAIR system implemented in numerous countries
Geologic Framework Model Analysis Model Report
R. Clayton
2000-12-19
The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M&O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and the
Geologic Framework Model Analysis Model Report
The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M and O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and
Collaborative networks: Reference modeling
L.M. Camarinha-Matos; H. Afsarmanesh
2008-01-01
Collaborative Networks: Reference Modeling works to establish a theoretical foundation for Collaborative Networks. Particular emphasis is put on modeling multiple facets of collaborative networks and establishing a comprehensive modeling framework that captures and structures diverse perspectives of
Earth Data Analysis Center, University of New Mexico — The model combines three modeled fire behavior parameters (rate of spread, flame length, crown fire potential) and one modeled ecological health measure (fire...
LSTM based Conversation Models
Luan, Yi; Ji, Yangfeng; Ostendorf, Mari
2016-01-01
In this paper, we present a conversational model that incorporates both context and participant role for two-party conversations. Different architectures are explored for integrating participant role and context information into a Long Short-term Memory (LSTM) language model. The conversational model can function as a language model or a language generation model. Experiments on the Ubuntu Dialog Corpus show that our model can capture multiple turn interaction between participants. The propos...
Computational neurogenetic modeling
Benuskova, Lubica
2010-01-01
Computational Neurogenetic Modeling is a student text, introducing the scope and problems of a new scientific discipline - Computational Neurogenetic Modeling (CNGM). CNGM is concerned with the study and development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes. These include neural network models and their integration with gene network models. This new area brings together knowledge from various scientific disciplines, such as computer and information science, neuroscience and cognitive science, genetics and molecular biol
National Aeronautics and Space Administration — CLAIRE MONTELEONI*, GAVIN SCHMIDT, AND SHAILESH SAROHA* Climate models are complex mathematical models designed by meteorologists, geophysicists, and climate...
Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...
Combustion modeling in a model combustor
L.Y.Jiang; I.Campbell; K.Su
2007-01-01
The flow-field of a propane-air diffusion flame combustor with interior and exterior conjugate heat transfers was numerically studied.Results obtained from four combustion models,combined with the re-normalization group (RNG) k-ε turbulence model,discrete ordinates radiation model and enhanced wall treatment are presented and discussed.The results are compared with a comprehensive database obtained from a series of experimental measurements.The flow patterns and the recirculation zone length in the combustion chamber are accurately predicted,and the mean axial velocities are in fairly good agreement with the experimental data,particularly at downstream sections for all four combustion models.The mean temperature profiles are captured fairly well by the eddy dissipation (EDS),probability density function (PDF),and laminar flamelet combustion models.However,the EDS-finite-rate combustion model fails to provide an acceptable temperature field.In general,the flamelet model illustrates little superiority over the PDF model,and to some extent the PDF model shows better performance than the EDS model.
ROCK PROPERTIES MODEL ANALYSIS MODEL REPORT
The purpose of this Analysis and Model Report (AMR) is to document Rock Properties Model (RPM) 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties models are intended principally for use as input to numerical physical-process modeling, such as of ground-water flow and/or radionuclide transport. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. This work was conducted in accordance with the following planning documents: WA-0344, ''3-D Rock Properties Modeling for FY 1998'' (SNL 1997, WA-0358), ''3-D Rock Properties Modeling for FY 1999'' (SNL 1999), and the technical development plan, Rock Properties Model Version 3.1, (CRWMS MandO 1999c). The Interim Change Notice (ICNs), ICN 02 and ICN 03, of this AMR were prepared as part of activities being conducted under the Technical Work Plan, TWP-NBS-GS-000003, ''Technical Work Plan for the Integrated Site Model, Process Model Report, Revision 01'' (CRWMS MandO 2000b). The purpose of ICN 03 is to record changes in data input status due to data qualification and verification activities. These work plans describe the scope, objectives, tasks, methodology, and implementing procedures for model construction. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The work scope for this activity consists of the following: (1) Conversion of the input data (laboratory measured porosity data, x-ray diffraction mineralogy, petrophysical calculations of bound water, and petrophysical calculations of porosity) for each borehole into stratigraphic coordinates; (2) Re-sampling and merging of data sets; (3) Development of geostatistical simulations of porosity; (4
ROCK PROPERTIES MODEL ANALYSIS MODEL REPORT
Clinton Lum
2002-02-04
The purpose of this Analysis and Model Report (AMR) is to document Rock Properties Model (RPM) 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties models are intended principally for use as input to numerical physical-process modeling, such as of ground-water flow and/or radionuclide transport. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. This work was conducted in accordance with the following planning documents: WA-0344, ''3-D Rock Properties Modeling for FY 1998'' (SNL 1997, WA-0358), ''3-D Rock Properties Modeling for FY 1999'' (SNL 1999), and the technical development plan, Rock Properties Model Version 3.1, (CRWMS M&O 1999c). The Interim Change Notice (ICNs), ICN 02 and ICN 03, of this AMR were prepared as part of activities being conducted under the Technical Work Plan, TWP-NBS-GS-000003, ''Technical Work Plan for the Integrated Site Model, Process Model Report, Revision 01'' (CRWMS M&O 2000b). The purpose of ICN 03 is to record changes in data input status due to data qualification and verification activities. These work plans describe the scope, objectives, tasks, methodology, and implementing procedures for model construction. The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The work scope for this activity consists of the following: (1) Conversion of the input data (laboratory measured porosity data, x-ray diffraction mineralogy, petrophysical calculations of bound water, and petrophysical calculations of porosity) for each borehole into stratigraphic coordinates; (2) Re-sampling and merging of data sets; (3
Business value modeling based on BPMN models
Masoumigoudarzi, Farahnaz
2014-01-01
In this study we will try to clarify the explanation of modeling and measuring 'Business Values', as it is defined in business context, in the business processes of a company and introduce different methods and select the one which is best for modeling the company's business values. These methods have been used by researchers in business analytics and senior managers of many companies. The focus in this project is business value detection and modeling. The basis of this research is on BPM...
A future of the model organism model
Rine, Jasper
2014-01-01
Changes in technology are fundamentally reframing our concept of what constitutes a model organism. Nevertheless, research advances in the more traditional model organisms have enabled fresh and exciting opportunities for young scientists to establish new careers and offer the hope of comprehensive understanding of fundamental processes in life. New advances in translational research can be expected to heighten the importance of basic research in model organisms and expand opportunities. Howe...
Failure prediction model: Model napovedovanja odpovedi:
Čelan, Štefan; Težak, Oto; Žižek, Adolf
2002-01-01
Preventative maintenance is vital for delicate technical products. Electronic components or the whole system must be changed, and thus need a good model that will indicate failure accurately. In this paper a stochastic stress-strength quantitative model is presented, folowing the five original hypothesis. Proposed new model of failure prediction could be used by the system maintenance. Failure risk could be instantaneosly calculated. The given theory considers the influences of stress on the ...
Better models are more effectively connected models
Nunes, João Pedro; Bielders, Charles; Darboux, Frederic; Fiener, Peter; Finger, David; Turnbull-Lloyd, Laura; Wainwright, John
2016-04-01
The concept of hydrologic and geomorphologic connectivity describes the processes and pathways which link sources (e.g. rainfall, snow and ice melt, springs, eroded areas and barren lands) to accumulation areas (e.g. foot slopes, streams, aquifers, reservoirs), and the spatial variations thereof. There are many examples of hydrological and sediment connectivity on a watershed scale; in consequence, a process-based understanding of connectivity is crucial to help managers understand their systems and adopt adequate measures for flood prevention, pollution mitigation and soil protection, among others. Modelling is often used as a tool to understand and predict fluxes within a catchment by complementing observations with model results. Catchment models should therefore be able to reproduce the linkages, and thus the connectivity of water and sediment fluxes within the systems under simulation. In modelling, a high level of spatial and temporal detail is desirable to ensure taking into account a maximum number of components, which then enables connectivity to emerge from the simulated structures and functions. However, computational constraints and, in many cases, lack of data prevent the representation of all relevant processes and spatial/temporal variability in most models. In most cases, therefore, the level of detail selected for modelling is too coarse to represent the system in a way in which connectivity can emerge; a problem which can be circumvented by representing fine-scale structures and processes within coarser scale models using a variety of approaches. This poster focuses on the results of ongoing discussions on modelling connectivity held during several workshops within COST Action Connecteur. It assesses the current state of the art of incorporating the concept of connectivity in hydrological and sediment models, as well as the attitudes of modellers towards this issue. The discussion will focus on the different approaches through which connectivity
Rahmani, Fouad Lazhar
2010-11-01
The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].
MacKay, N. J.
2006-01-01
An overview of Lanchester combat models, emphasising their pedagogical possibilities. After a description of the aimed-fire model and comments on the literature, we introduce briefly a range of further topics: a discrete equivalent, the unaimed-fire model, mixed forces, the meaning of a 'unit', support troops, Bracken's generalization and an asymmetric model.
Ibsen, Lars Bo; Liingaard, M.
2006-12-15
A lumped-parameter model represents the frequency dependent soil-structure interaction of a massless foundation placed on or embedded into an unbounded soil domain. In this technical report the steps of establishing a lumped-parameter model are presented. Following sections are included in this report: Static and dynamic formulation, Simple lumped-parameter models and Advanced lumped-parameter models. (au)
Croft, Barbara Y.
2002-01-01
Animal models can be used in the study of disease. This chapter discusses imaging animal models to elucidate the process of human disease. The mouse is used as the primary model. Though this choice simplifies many research choices, it necessitates compromises for in vivo imaging. In the future, we can expect improvements in both animal models and imaging techniques.
Andrist, Rafael B.; Haworth, Guy McCrossan
2005-01-01
A reference model of Fallible Endgame Play has been implemented and exercised with the chess-engine WILHELM. Past experiments have demonstrated the value of the model and the robustness of decisions based on it: experiments agree well with a Markov Model theory. Here, the reference model is exercised on the well-known endgame KBBKN.
Generative Models of Disfluency
Miller, Timothy A.
2010-01-01
This thesis describes a generative model for representing disfluent phenomena in human speech. This model makes use of observed syntactic structure present in disfluent speech, and uses a right-corner transform on syntax trees to model this structure in a very natural way. Specifically, the phenomenon of speech repair is modeled by explicitly…
Modelling Railway Interlocking Systems
Lindegaard, Morten Peter; Viuf, P.; Haxthausen, Anne Elisabeth
2000-01-01
In this report we present a model of interlocking systems, and describe how the model may be validated by simulation. Station topologies are modelled by graphs in which the nodes denote track segments, and the edges denote connectivity for train traÆc. Points and signals are modelled by annotatio...
On Multiobjective Evolution Model
Ahmed, E; Elettreby, M. F.
2004-01-01
Self-Organized Criticality (SOC) phenomena could have a significant effect on the dynamics of ecosystems. The Bak-Sneppen (BS) model is a simple and robust model of biological evolution that exhibits punctuated equilibrium behavior. Here we will introduce random version of BS model. Also we generalize the single objective BS model to a multiobjective one.
On Multiobjective Evolution Model
Ahmed, E.; Elettreby, M. F.
Self-Organized Criticality (SOC) phenomena could have a significant effect on the dynamics of ecosystems. The Bak-Sneppen (BS) model is a simple and robust model of biological evolution that exhibits punctuated equilibrium behavior. Here, we will introduce random version of BS model. We also generalize the single objective BS model to a multiobjective one.
2015-09-01
The Biomass Scenario Model (BSM) is a unique, carefully validated, state-of-the-art dynamic model of the domestic biofuels supply chain which explicitly focuses on policy issues, their feasibility, and potential side effects. It integrates resource availability, physical/technological/economic constraints, behavior, and policy. The model uses a system dynamics simulation (not optimization) to model dynamic interactions across the supply chain.
Masonry behavior and modelling
Angelillo, Maurizio; Lourenço, Paulo B.; Milani, G.
2014-01-01
In this Chapter we present the basic experimental facts on masonry materials and introduce simple and refined models for masonry. The simple models are essentially macroscopic and based on the assumption that the material is incapable of sustaining tensile loads (No-Tension assumption). The refined models account for the microscopic structure of masonry, modeling the interaction between the blocks and the interfaces.
Numerical Modelling of Streams
Vestergaard, Kristian
In recent years there has been a sharp increase in the use of numerical water quality models. Numeric water quality modeling can be divided into three steps: Hydrodynamic modeling for the determination of stream flow and water levels. Modelling of transport and dispersion of a conservative...
Gernaey, Krist; Sin, Gürkan
2008-01-01
The state-of-the-art level reached in modeling wastewater treatment plants (WWTPs) is reported. For suspended growth systems, WWTP models have evolved from simple description of biological removal of organic carbon and nitrogen in aeration tanks (ASM1 in 1987) to more advanced levels including...... practice of WWTP modeling by linking the wastewater treatment line with the sludge handling line in one modeling platform. Application of WWTP models is currently rather time consuming and thus expensive due to the high model complexity, and requires a great deal of process knowledge and modeling expertise...
Gernaey, Krist; Sin, Gürkan
2011-01-01
The state-of-the-art level reached in modeling wastewater treatment plants (WWTPs) is reported. For suspended growth systems, WWTP models have evolved from simple description of biological removal of organic carbon and nitrogen in aeration tanks (ASM1 in 1987) to more advanced levels including...... WWTP modeling by linking the wastewater treatment line with the sludge handling line in one modeling platform. Application of WWTP models is currently rather time consuming and thus expensive due to the high model complexity, and requires a great deal of process knowledge and modeling expertise...
The Hanford Environmental Dose Reconstruction (HEDR) Project has developed a set of computer models for estimating the possible radiation doses that individuals may have received from past Hanford Site operations. This document describes the validation of these models. In the HEDR Project, the model validation exercise consisted of comparing computational model estimates with limited historical field measurements and experimental measurements that are independent of those used to develop the models. The results of any one test do not mean that a model is valid. Rather, the collection of tests together provide a level of confidence that the HEDR models are valid
Sen S; Moha N.; Baudry B.; Jezequel J.-M.
2009-01-01
International audience Large and complex meta-models such as those of Uml and its profiles are growing due to modelling and inter-operability needs of numerous stakeholders. The complexity of such meta-models has led to coining of the term meta-muddle. Individual users often exercise only a small view of a meta-muddle for tasks ranging from model creation to construction of model transformations. What is the effective meta-model that represents this view? We present a flexible meta-model p...
The Hanford Environmental Dose Reconstruction (HEDR) Project has developed a set of computer models for estimating the possible radiation doses that individuals may have received from past Hanford Site operations. This document describes the validation of these models. In the HEDR Project, the model validation exercise consisted of comparing computational model predictions with limited historical field measurements and experimental measurements that are independent of those used to develop the models. The results of any one test do not mean that a model is valid. Rather, the collection of tests together provide a level of confidence that the HEDR models are valid
Conceptual Model for Communication
Fedaghi, Sabah Al; Fadel, Zahraa
2009-01-01
A variety of idealized models of communication systems exist, and all may have something in common. Starting with Shannons communication model and ending with the OSI model, this paper presents progressively more advanced forms of modeling of communication systems by tying communication models together based on the notion of flow. The basic communication process is divided into different spheres (sources, channels, and destinations), each with its own five interior stages, receiving, processing, creating, releasing, and transferring of information. The flow of information is ontologically distinguished from the flow of physical signals, accordingly, Shannons model, network based OSI models, and TCP IP are redesigned.
Widera, Paweł
2011-01-01
The process of comparison of computer generated protein structural models is an important element of protein structure prediction. It has many uses including model quality evaluation, selection of the final models from a large set of candidates or optimisation of parameters of energy functions used in template free modelling and refinement. Although many protein comparison methods are available online on numerous web servers, their ability to handle a large scale model comparison is often very limited. Most of the servers offer only a single pairwise structural comparison, and they usually do not provide a model-specific comparison with a fixed alignment between the models. To bridge the gap between the protein and model structure comparison we have developed the Protein Models Comparator (pm-cmp). To be able to deliver the scalability on demand and handle large comparison experiments the pm-cmp was implemented "in the cloud". Protein Models Comparator is a scalable web application for a fast distributed comp...
Deconfinement phase transition in neutron star matter
LI Ang; PENG Guang-Xiong; Lombardo U
2009-01-01
The transition from hadron phase to strange quark phase in dense matter is investigated. Instead of using the conventional bag model in quark sect, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates, with a thermodynamic problem improved. In nuclear slot,we adopt the equation of state from Brueckner-Bethe-Goldstone approach with three-body force. It is found that the mixed phase can occur, for reasonable confinement parameter, near the normal saturation density,and transit to pure quark matter at 4-5 times the saturation, which is quite different from the previous results from other quark models that pure quark phase can not appear at neutron-star densities.
Conceptual Model for Communication
Zahra'a Fadel; Ala'a Alsaqa; Sabah Al-Fedaghi
2009-01-01
A variety of idealized models of communication systems exist, and all may have something in common. Starting with Shannon’s communication model and ending with the OSI model, this paper presents progressively more advanced forms of modeling of communication systems by tying communication models together based on the notion of flow. The basic communication process is divided into different spheres (sources, channels, and destinations), each with its own five interior stages: receiving, process...
Høskuldsson, Agnar
1996-01-01
Determination of the proper dimension of a given linear model is one of the most important tasks in the applied modeling work. We consider here eight criteria that can be used to determine the dimension of the model, or equivalently, the number of components to use in the model. Four of these...... the basic problems in determining the dimension of linear models. Then each of the eight measures are treated. The results are illustrated by examples....
Visualizing Risk Prediction Models
Vanya Van Belle; Ben Van Calster
2015-01-01
Objective Risk prediction models can assist clinicians in making decisions. To boost the uptake of these models in clinical practice, it is important that end-users understand how the model works and can efficiently communicate its results. We introduce novel methods for interpretable model visualization. Methods The proposed visualization techniques are applied to two prediction models from the Framingham Heart Study for the prediction of intermittent claudication and stroke after atrial fib...
William Poole
2006-01-01
Most monetary economists today conduct their analysis within some version of a rational expectations model. A well-defined equilibrium in such a model requires that the private sector understand policy goals and the policymakers' model of the economy. An austere version of the model, with no information asymmetries, is valid only to a first approximation but nevertheless provides core insights to short- and long-run monetary policy. In this model, effective policy requires clarity of policy g...
Slavik Stefan; Bednar Richard
2014-01-01
The term business model has been used in practice for few years, but companies create, define and innovate their models subconsciously from the start of business. Our paper is aimed to clear the theory about business model, hence definition and all the components that form each business. In the second part, we create an analytical tool and analyze the real business models in Slovakia and define the characteristics of each part of business model, i.e., customers, distribution, value, resour...
Inference for Multiplicative Models
Wexler, Ydo; Meek, Christopher
2012-01-01
The paper introduces a generalization for known probabilistic models such as log-linear and graphical models, called here multiplicative models. These models, that express probabilities via product of parameters are shown to capture multiple forms of contextual independence between variables, including decision graphs and noisy-OR functions. An inference algorithm for multiplicative models is provided and its correctness is proved. The complexity analysis of the inference algorithm uses a mor...
Wortelboer FG
1994-01-01
This report contains the descriptions of the models currently used within the National Institute of Public Health and Environmental Protection (RIVM). Each model description contains the following entries: Name of the model, Contact in RIVM, Purpose, Policy theme, Technical specifications, Status, Availability, Documentation. Besides, the report contains a list of the models grouped by laboratory, a list of the models grouped by theme, and an index. The purpose of this report is both to give ...