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Sample records for agents fdtd simulation

  1. Electromagnetic simulation using the FDTD method

    CERN Document Server

    Sullivan, Dennis M

    2013-01-01

    A straightforward, easy-to-read introduction to the finite-difference time-domain (FDTD) method Finite-difference time-domain (FDTD) is one of the primary computational electrodynamics modeling techniques available. Since it is a time-domain method, FDTD solutions can cover a wide frequency range with a single simulation run and treat nonlinear material properties in a natural way. Written in a tutorial fashion, starting with the simplest programs and guiding the reader up from one-dimensional to the more complex, three-dimensional programs, this book provides a simple, yet comp

  2. Flow cytometry with gold nanoparticlesand their clusters as scattering contrast agents: FDTD simulation of light-cell interaction

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Sun, Wenbo; Pond, James;

    2009-01-01

    The formulation of the Finite-Difference Time-Domain (FDTD) approach is presented in the framework of its potential applications to in vivo flow cytometry based on light scattering. The consideration is focused on comparison of light scattering by a single biological cell alone in controlled...... avenue in the development of advanced cytometric techniques based on scattering effects from nanoscale targets....

  3. Electromagnetic metamaterial simulations using a GPU-accelerated FDTD method

    Science.gov (United States)

    Seok, Myung-Su; Lee, Min-Gon; Yoo, SeokJae; Park, Q.-Han

    2015-12-01

    Metamaterials composed of artificial subwavelength structures exhibit extraordinary properties that cannot be found in nature. Designing artificial structures having exceptional properties plays a pivotal role in current metamaterial research. We present a new numerical simulation scheme for metamaterial research. The scheme is based on a graphic processing unit (GPU)-accelerated finite-difference time-domain (FDTD) method. The FDTD computation can be significantly accelerated when GPUs are used instead of only central processing units (CPUs). We explain how the fast FDTD simulation of large-scale metamaterials can be achieved through communication optimization in a heterogeneous CPU/GPU-based computer cluster. Our method also includes various advanced FDTD techniques: the non-uniform grid technique, the total-field/scattered-field (TFSF) technique, the auxiliary field technique for dispersive materials, the running discrete Fourier transform, and the complex structure setting. We demonstrate the power of our new FDTD simulation scheme by simulating the negative refraction of light in a coaxial waveguide metamaterial.

  4. A New Wide Band Planar Antenna and FDTD Simulation

    Institute of Scientific and Technical Information of China (English)

    WANGHonziian; GAOBenqing

    2003-01-01

    A new planar trigonometric curve (PTC)antenna is firstly proposed. The finite difference time domain method (FDTD) is used to analysis the input impedance and pattern of this antenna. The image the-ory is firstly applied to obtain the impedance using FDTD.Using the image theory the computation time and RAMspace needed by the calculation of monopole antenna can be reduced greatly, while the results remain almost the same level as those of the experiments. The FDTD sim-ulation of this PTC antenna exhibit the very wide band results in impedance (14:1) and pattern (5.7:1), which are much better than those of the circular disc monopole an-tenna (CMA) and Trilateral monoDole antenna (TLA).

  5. Simulation of ultrasonic and EMAT arrays using FEM and FDTD.

    Science.gov (United States)

    Xie, Yuedong; Yin, Wuliang; Liu, Zenghua; Peyton, Anthony

    2016-03-01

    This paper presents a method which combines electromagnetic simulation and ultrasonic simulation to build EMAT array models. For a specific sensor configuration, Lorentz forces are calculated using the finite element method (FEM), which then can feed through to ultrasonic simulations. The propagation of ultrasound waves is numerically simulated using finite-difference time-domain (FDTD) method to describe their propagation within homogenous medium and their scattering phenomenon by cracks. Radiation pattern obtained with Hilbert transform on time domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle. PMID:26596420

  6. 3D FDTD simulations of photonic devices

    International Nuclear Information System (INIS)

    Full text: In our contribution we will present the recent results on 3D simulations of photonic devices. Particularly, quantum well infrared photodetectors with embedded photonic crystal are optimized to achieve optimal light coupling and quantum efficiency. Furthermore, we study schemes of light coupling into SOI waveguides. Both optical fibre-SOI waveguide and laser-SOI waveguide coupling schemes are investigated. The results of investigations regarding the influence of disorder on the reflection peak in opal 3D photonic crystal will be also presented. This work was supported by the Austrian Nanoinitiative RPC PLATON. (author)

  7. Optical simulation of surface textured TCO using FDTD method

    Science.gov (United States)

    Elviyanti, I. L.; Purwanto, H.; Kusumandari

    2016-02-01

    The purpose of this research is simulating the transmittance of surface textured transparent conducting oxide (TCO) for Dye-Sensitized Solar Cell (DSSC) application. The simulation based on finite difference time domain (FDTD) was performed using the MatLab software for flat and pyramid surface textured TCO. Fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) were used as TCO material. The transmittance simulation of flat TCO was compared to UV-Vis spectrophotometer measurement of real TCO to ensure the accuracy of the simulation. Then, the transmittance simulation of pyramid surface textures of TCO is higher than a flat one. It suggested that surface texturing enhance the path of light through dispersion and reflectance light by the pattern of the surface. This result indicates that surface textured increasing the transmittance of TCO through a complex light trapping mechanism which might be used to increase the light harvesting for DSSC application.

  8. FDTD simulations of the losses in complex electromagnetic cavities

    Science.gov (United States)

    Moglie, Franco; Bastianelli, Luca; Mariani Primiani, Valter; EMC Team

    The simulations of complex electromagnetic cavities like reverberation chambers (RC) require a massive parallel computer to accurately account the complex three dimensional geometry. A parallel finite-difference time-domain (FDTD) code optimized for a massive parallel computer could lose its efficiency if the losses are concentrated in some part of the computation volume. For example, the simulation of the finite conductivity of the cavity metallic walls requires a significant overcharge for the computer processors that handle the boundary part of the global computational domain. Our in-house parallel FDTD code replaces the volumetric losses in every cell of the grid instead of the Ohmic losses on the walls. In this contribution, we evaluate the difference in the field distribution inside the cavity due to this replacement. Moreover, we compare the common RC statistics like the number of stirrer uncorrelated positions and the field uniformity, and the resources required for the two methods are reported and discussed. Finally, the numerical results will be compared with the measurements of the RC in our laboratory with a volume of 60 m3 and plated steel walls in the frequency range 0.2-1.0 GHz, that includes the transition from the undermoded to the overmoded region. We acknowledge PRACE for awarding us access to resource FERMI based in Italy at CINECA.

  9. EMC/FDTD/MD simulation of carrier transport and electrodynamics in two-dimensional electron systems

    OpenAIRE

    Sule, N; Willis, K. J.; Hagness, S. C.; Knezevic, I.

    2014-01-01

    We present the implementation and application of a multiphysics simulation technique to carrier dynamics under electromagnetic excitation in supported two-dimensional electronic systems. The technique combines ensemble Monte Carlo (EMC) for carrier transport with finite-difference time-domain (FDTD) for electrodynamics and molecular dynamics (MD) for short-range Coulomb interactions among particles. We demonstrate the use of this EMC/FDTD/MD technique by calculating the room-temperature dc an...

  10. An Optimized Parallel FDTD Topology for Challenging Electromagnetic Simulations on Supercomputers

    Directory of Open Access Journals (Sweden)

    Shugang Jiang

    2015-01-01

    Full Text Available It may not be a challenge to run a Finite-Difference Time-Domain (FDTD code for electromagnetic simulations on a supercomputer with more than 10 thousands of CPU cores; however, to make FDTD code work with the highest efficiency is a challenge. In this paper, the performance of parallel FDTD is optimized through MPI (message passing interface virtual topology, based on which a communication model is established. The general rules of optimal topology are presented according to the model. The performance of the method is tested and analyzed on three high performance computing platforms with different architectures in China. Simulations including an airplane with a 700-wavelength wingspan, and a complex microstrip antenna array with nearly 2000 elements are performed very efficiently using a maximum of 10240 CPU cores.

  11. FDTD Simulation on Terahertz Waves Propagation Through a Dusty Plasma

    Science.gov (United States)

    Wang, Maoyan; Zhang, Meng; Li, Guiping; Jiang, Baojun; Zhang, Xiaochuan; Xu, Jun

    2016-08-01

    The frequency dependent permittivity for dusty plasmas is provided by introducing the charging response factor and charge relaxation rate of airborne particles. The field equations that describe the characteristics of Terahertz (THz) waves propagation in a dusty plasma sheath are derived and discretized on the basis of the auxiliary differential equation (ADE) in the finite difference time domain (FDTD) method. Compared with numerical solutions in reference, the accuracy for the ADE FDTD method is validated. The reflection property of the metal Aluminum interlayer of the sheath at THz frequencies is discussed. The effects of the thickness, effective collision frequency, airborne particle density, and charge relaxation rate of airborne particles on the electromagnetic properties of Terahertz waves through a dusty plasma slab are investigated. Finally, some potential applications for Terahertz waves in information and communication are analyzed. supported by National Natural Science Foundation of China (Nos. 41104097, 11504252, 61201007, 41304119), the Fundamental Research Funds for the Central Universities (Nos. ZYGX2015J039, ZYGX2015J041), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20120185120012)

  12. The use of MR B+1 imaging for validation of FDTD electromagnetic simulations of human anatomies

    International Nuclear Information System (INIS)

    In this study, MR B+1 imaging is employed to experimentally verify the validity of FDTD simulations of electromagnetic field patterns in human anatomies. Measurements and FDTD simulations of the B+1 field induced by a 3 T MR body coil in a human corpse were performed. It was found that MR B+1 imaging is a sensitive method to measure the radiofrequency (RF) magnetic field inside a human anatomy with a precision of approximately 3.5%. A good correlation was found between the B+1 measurements and FDTD simulations. The measured B+1 pattern for a human pelvis consisted of a global, diagonal modulation pattern plus local B+1 heterogeneties. It is believed that these local B+1 field variations are the result of peaks in the induced electric currents, which could not be resolved by the FDTD simulations on a 5 mm3 simulation grid. The findings from this study demonstrate that B+1 imaging is a valuable experimental technique to gain more knowledge about the dielectric interaction of RF fields with the human anatomy

  13. Development of FDTD simulation tool for designing micro-nanostructured based optical devices

    Science.gov (United States)

    Shrestha, Anil; Mizuno, Genki; Oduor, Patrick; Islam, Saif; Dutta, Achyut K.; Dhar, Nibir K.

    2016-05-01

    The use of Graphics Processing Unit (GPU) for computational work has revolutionized how complex electromagnetic problems are solved. Complex problems which required supercomputers in the past for analysis can now be tackled and solved using personal computers by channeling the computational work towards GPUs instead of the traditional computer Central Processing Unit (CPU). Finite-Difference Time-Domain (FDTD) analysis, which is a computationally expensive method of solving electromagnetic problems is highly parallel in nature and can be readily executed in a GPU. We have developed an algorithm for three dimensional FDTD analysis of optical devices with micro and nano-structures using Compute Unified Device Architecture (CUDA). The developed algorithm exploits the benefits of multiple cores of GPU chips and boosts the speed of simulation without sacrificing its accuracy. We achieved a 25-fold speed up of simulation using CUDA compared to MATLAB code in CPU.

  14. A Simple FDTD Algorithm for Simulating EM-Wave Propagation in General Dispersive Anisotropic Material

    KAUST Repository

    Al-Jabr, Ahmad Ali

    2013-03-01

    In this paper, an finite-difference time-domain (FDTD) algorithm for simulating propagation of EM waves in anisotropic material is presented. The algorithm is based on the auxiliary differential equation and the general polarization formulation. In anisotropic materials, electric fields are coupled and elements in the permittivity tensor are, in general, multiterm dispersive. The presented algorithm resolves the field coupling using a formulation based on electric polarizations. It also offers a simple procedure for the treatment of multiterm dispersion in the FDTD scheme. The algorithm is tested by simulating wave propagation in 1-D magnetized plasma showing excellent agreement with analytical solutions. Extension of the algorithm to multidimensional structures is straightforward. The presented algorithm is efficient and simple compared to other algorithms found in the literature. © 2012 IEEE.

  15. An FDTD algorithm for simulation of EM waves propagation in laser with static and dynamic gain models

    KAUST Repository

    Al-Jabr, Ahmad Ali

    2013-01-01

    This paper presents methods of simulating gain media in the finite difference time-domain (FDTD) algorithm utilizing a generalized polarization formulation. The gain can be static or dynamic. For static gain, Lorentzian and non-Lorentzian models are presented and tested. For the dynamic gain, rate equations for two-level and four-level models are incorporated in the FDTD scheme. The simulation results conform with the expected behavior of wave amplification and dynamic population inversion.

  16. Simulation of Optical Devices Using Parallel FDTD Method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    On this paper, we investigate the algorithm and efficiency of simulation of optical devices using parallel computing method, implement some real wavelength division multiplexing (WDM) components such as resonators to test the method's possibility and efficiency.

  17. Numerical simulation of nanopulse penetration of biological matter using the ADI-FDTD method

    Science.gov (United States)

    Zhu, Fei

    Nanopulses are ultra-wide-band (UWB) electromagnetic pulses with pulse duration of only a few nanoseconds and electric field amplitudes greater than 105 V/m. They have been widely used in the development of new technologies in the field of medicine. Therefore, the study of the nanopulse bioeffects is important to ensure the appropriate application with nanopulses in biomedical and biotechnological settings. The conventional finite-difference time-domain (FDTD) method for solving Maxwell's equations has been proven to be an effective method to solve the problems related to electromagnetism. However, its application is restricted by the Courant, Friedrichs, and Lewy (CFL) stability condition that confines the time increment and mesh size in the computation in order to prevent the solution from being divergent. This dissertation develops a new finite difference scheme coupled with the Cole-Cole expression for dielectric coefficients of biological tissues to simulate the electromagnetic fields inside biological tissues when exposed to nanopulses. The scheme is formulated based on the Yee's cell and alternating direction implicit (ADI) technique. The basic idea behind the ADI technique is to break up every time step into two half-time steps. At the first half-step, the finite difference operator on the right-hand side of the Maxwell's equation is implicit only along one coordinate axis direction. At the second half-step, the finite difference operator on the right-hand side of the Maxwell's equation is implicit only along the other coordinate axis direction. As such, only tridiagonal linear systems are solved. In this numerical method, the Cole-Cole expression is approximated by a second-order Taylor series based on the z-transform method. In addition, the perfectly matched layer is employed for the boundary condition, and the total/scattered field technique is employed to generate the plane wave in order to prevent the wave reflection. The scheme is tested by numerical

  18. Interactive visualization system to analyze corrugated millimeter-waveguide component of ECH in nuclear fusion with FDTD simulation

    International Nuclear Information System (INIS)

    We have simulated distribution of electromagnetic waves through the system composed of miter bends by Finite-Difference Time-Domain (FDTD) simulation. We develop the interactive visualization system using a new interactive GUI system which is composed of the virtual reality system and android tablet to analyze the FDTD simulation. The effect of the waveguide system with grooves have been investigated to quantitatively by visualization system. Comparing waveguide system with grooves and without grooves, grooves have been confirmed to suppress the surface current at the metal surface. The surface current at complex shape such as the miter bend have been investigated

  19. Interactive visualization system to analyze corrugated millimeter-waveguide component of ECH in nuclear fusion with FDTD simulation

    Science.gov (United States)

    Kashima, N.; Nakamura, H.; Tamura, Y.; Ito, A. M.; Kubo, S.

    2014-03-01

    We have simulated distribution of electromagnetic waves through the system composed of miter bends by Finite-Difference Time-Domain (FDTD) simulation. We develop the interactive visualization system using a new interactive GUI system which is composed of the virtual reality system and android tablet to analyze the FDTD simulation. The effect of the waveguide system with grooves have been investigated to quantitatively by visualization system. Comparing waveguide system with grooves and without grooves, grooves have been confirmed to suppress the surface current at the metal surface. The surface current at complex shape such as the miter bend have been investigated.

  20. FDTD simulation of LEMP propagation over lossy ground: Influence of distance, ground conductivity, and source parameters

    Science.gov (United States)

    Aoki, Masanori; Baba, Yoshihiro; Rakov, Vladimir A.

    2015-08-01

    We have computed lightning electromagnetic pulses (LEMPs), including the azimuthal magnetic field Hφ, vertical electric field Ez, and horizontal (radial) electric field Eh that propagated over 5 to 200 km of flat lossy ground, using the finite difference time domain (FDTD) method in the 2-D cylindrical coordinate system. This is the first systematic full-wave study of LEMP propagation effects based on a realistic return-stroke model and including the complete return-stroke frequency range. Influences of the return-stroke wavefront speed (ranging from c/2 to c, where c is the speed of light), current risetime (ranging from 0.5 to 5 µs), and ground conductivity (ranging from 0.1 mS/m to ∞) on Hφ, Ez, and Eh have been investigated. Also, the FDTD-computed waveforms of Eh have been compared with the corresponding ones computed using the Cooray-Rubinstein formula. Peaks of Hφ, Ez, and Eh are nearly proportional to the return-stroke wavefront speed. The peak of Eh decreases with increasing current risetime, while those of Hφ and Ez are only slightly influenced by it. The peaks of Hφ and Ez are essentially independent of the ground conductivity at a distance of 5 km. Beyond this distance, they appreciably decrease relative to the perfectly conducting ground case, and the decrease is stronger for lower ground conductivity values. The peak of Eh increases with decreasing ground conductivity. The computed Eh/Ez is consistent with measurements of Thomson et al. (1988). The observed decrease of Ez peak and increase of Ez risetime due to propagation over 200 km of Florida soil are reasonably well reproduced by the FDTD simulation with ground conductivity of 1 mS/m.

  1. MEEP: A flexible free-software package for electromagnetic simulations by the FDTD method

    Science.gov (United States)

    Oskooi, Ardavan F.; Roundy, David; Ibanescu, Mihai; Bermel, Peter; Joannopoulos, J. D.; Johnson, Steven G.

    2010-03-01

    This paper describes Meep, a popular free implementation of the finite-difference time-domain (FDTD) method for simulating electromagnetism. In particular, we focus on aspects of implementing a full-featured FDTD package that go beyond standard textbook descriptions of the algorithm, or ways in which Meep differs from typical FDTD implementations. These include pervasive interpolation and accurate modeling of subpixel features, advanced signal processing, support for nonlinear materials via Padé approximants, and flexible scripting capabilities. Program summaryProgram title: Meep Catalogue identifier: AEFU_v1_0 Program summary URL::http://cpc.cs.qub.ac.uk/summaries/AEFU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL No. of lines in distributed program, including test data, etc.: 151 821 No. of bytes in distributed program, including test data, etc.: 1 925 774 Distribution format: tar.gz Programming language: C++ Computer: Any computer with a Unix-like system and a C++ compiler; optionally exploits additional free software packages: GNU Guile [1], libctl interface library [2], HDF5 [3], MPI message-passing interface [4], and Harminv filter-diagonalization [5]. Developed on 2.8 GHz Intel Core 2 Duo. Operating system: Any Unix-like system; developed under Debian GNU/Linux 5.0.2. RAM: Problem dependent (roughly 100 bytes per pixel/voxel) Classification: 10 External routines: Optionally exploits additional free software packages: GNU Guile [1], libctl interface library [2], HDF5 [3], MPI message-passing interface [4], and Harminv filter-diagonalization [5] (which requires LAPACK and BLAS linear-algebra software [6]). Nature of problem: Classical electrodynamics Solution method: Finite-difference time-domain (FDTD) method Running time: Problem dependent (typically about 10 ns per pixel per timestep) References:[1] GNU Guile, http://www.gnu.org/software/guile[2] Libctl, http

  2. Simulation of an Electromagnetic Acoustic Transducer Array by Using Analytical Method and FDTD

    Directory of Open Access Journals (Sweden)

    Yuedong Xie

    2016-01-01

    Full Text Available Previously, we developed a method based on FEM and FDTD for the study of an Electromagnetic Acoustic Transducer Array (EMAT. This paper presents a new analytical solution to the eddy current problem for the meander coil used in an EMAT, which is adapted from the classic Deeds and Dodd solution originally intended for circular coils. The analytical solution resulting from this novel adaptation exploits the large radius extrapolation and shows several advantages over the finite element method (FEM, especially in the higher frequency regime. The calculated Lorentz force density from the analytical EM solver is then coupled to the ultrasonic simulations, which exploit the finite-difference time-domain (FDTD method to describe the propagation of ultrasound waves, in particular for Rayleigh waves. Radiation pattern obtained with Hilbert transform on time-domain waveforms is proposed to characterise the sensor in terms of its beam directivity and field distribution along the steering angle, which can produce performance parameters for an EMAT array, facilitating the optimum design of such sensors.

  3. Fabrication of plasmonic thin films and their characterization by optical method and FDTD simulation technique

    Science.gov (United States)

    Kuzma, A.; Uherek, F.; Å kriniarová, J.; Pudiš, D.; Weis, M.; Donoval, M.

    2015-08-01

    In this paper we present optical properties of thin metal films deposited on the glass substrates by the physical vapor deposition. Localized surface plasmon polaritons of different film thicknesses have been spectrally characterized by optical methods. Evidence of the Au nanoparticles in deposited thin films have been demonstrated by Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) and their dimensions as well as separations have been evaluated. As a first approximation, the simulation model of deposited nanoparticles without assuming their dimension and separation distributions has been created. Simulation model defines relation between the nanoparticle dimensions and their separations. Model of deposited nanoparticles has been simulated by the Finite-Difference Time-Domain (FDTD) simulation method. The pulsed excitation has been used and transmission of optical radiation has been calculated from the spectral response by Fast Fourier Transform (FFT) analyses. Plasmonic extinctions have been calculated from measured spectral characteristics as well as simulated characteristics and compared with each other. The nanoparticle dimensions and separations have been evaluated from the agreement between the simulation and experimental spectral characteristics. Surface morphology of thin metal film has been used as an input for the detail simulation study based on the experimental observation of metal nanoparticle distribution. Hence, this simulation method includes appropriate coupling effects between nanoparticles and provides more reliable results. Obtained results are helpful for further deep understanding of thin metal films plasmonic properties and simulation method is demonstrated as a powerful tool for the deposition technology optimizations.

  4. An FDTD algorithm for simulating light propagation in anisotropic dynamic gain media

    KAUST Repository

    Al-Jabr, A. A.

    2014-05-02

    Simulating light propagation in anisotropic dynamic gain media such as semiconductors and solid-state lasers using the finite difference time-domain FDTD technique is a tedious process, as many variables need to be evaluated in the same instant of time. The algorithm has to take care of the laser dynamic gain, rate equations, anisotropy and dispersion. In this paper, to the best of our knowledge, we present the first algorithm that solves this problem. The algorithm is based on separating calculations into independent layers and hence solving each problem in a layer of calculations. The anisotropic gain medium is presented and tested using a one-dimensional set-up. The algorithm is then used for the analysis of a two-dimensional problem.

  5. Simulation of Plasmonics Nanodevices with Coupled Maxwell and Schrödinger Equations using the FDTD Method

    Directory of Open Access Journals (Sweden)

    Iftikhar Ahmed

    2012-05-01

    Full Text Available Maxwell and Schrödinger equations are coupled to incorporate quantum effects for the simulation of plasmonics nanodevices. Maxwell equations with Lorentz-Drude (LD dispersive model are applied to large size plasmonics components, whereas coupled Maxwell and Schrödinger equations are applied to components where quantum effects are needed. The finite difference time domain method (FDTD is applied to simulate these coupled equations.

  6. One-step leapfrog ADI-FDTD method for simulating electromagnetic wave propagation in general dispersive media.

    Science.gov (United States)

    Wang, Xiang-Hua; Yin, Wen-Yan; Chen, Zhi Zhang David

    2013-09-01

    The one-step leapfrog alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is reformulated for simulating general electrically dispersive media. It models material dispersive properties with equivalent polarization currents. These currents are then solved with the auxiliary differential equation (ADE) and then incorporated into the one-step leapfrog ADI-FDTD method. The final equations are presented in the form similar to that of the conventional FDTD method but with second-order perturbation. The adapted method is then applied to characterize (a) electromagnetic wave propagation in a rectangular waveguide loaded with a magnetized plasma slab, (b) transmission coefficient of a plane wave normally incident on a monolayer graphene sheet biased by a magnetostatic field, and (c) surface plasmon polaritons (SPPs) propagation along a monolayer graphene sheet biased by an electrostatic field. The numerical results verify the stability, accuracy and computational efficiency of the proposed one-step leapfrog ADI-FDTD algorithm in comparison with analytical results and the results obtained with the other methods. PMID:24103929

  7. Characterization and FDTD simulation analysis on light trapping structures of amorphous silicon thin films by laser irradiation

    Science.gov (United States)

    Huang, Lu; Jin, Jing; Yuan, Zhijun; Yang, Weiguang; Wang, Linjun; Shi, Weimin; Zhou, Jun; Lou, Qihong

    2016-05-01

    The effect of laser energy density on the light-trapping structures of amorphous silicon (α-Si) thin films is studied both theoretically and experimentally. The thin films are irradiated by a frequency-doubled (λ = 532 nm) Nd:YAG pulsed nanosecond laser. An effective finite difference time domain (FDTD) model is built to find the optimized laser energy density (EL) for the light trapping structures of α-Si. Based on the simulation analysis, it shows the variation of reflection spectra with laser energy density. The optimized reflection spectra at EL = 1000 mJ/cm2 measured by UV-visible spectroscopy confirms to agree well with that corresponding to the depth to diameter ratio (h/D) in the FDTD simulation. The surface morphology characterization by optical microscope (OM) and scanning electron microscope (SEM) accords fairly well to of light-trapping modeling in the simulation.

  8. High accuracy models of sources in FDTD computations for subwavelength photonics design simulations

    Science.gov (United States)

    Cole, James B.; Banerjee, Saswatee

    2014-09-01

    The simple source model used in the conventional finite difference time domain (FDTD) algorithm gives rise to large errors. Conventional second-order FDTD has large errors (order h**2/ 12), h = grid spacing), and the errors due to the source model further increase this error. Nonstandard (NS) FDTD, based on a superposition of second-order finite differences, has been demonstrated to give much higher accuracy than conventional FDTD for the sourceless wave equation and Maxwell's equations (h**6 / 24192). Since the Green's function for the wave equation in free space is known, we can compute the field due to a point source. This analytical solution is inserted into the NS finite difference (FD) model and the parameters of the source model are adjusted so that the FDTD solution matches the analytical one. To derive the scattered field source model, we use the NS-FD model of the total field and of the incident field to deduce the correct source model. We find that sources that generate a scattered field must be modeled differently from ones radiate into free space. We demonstrate the high accuracy of our source models by comparing with analytical solutions. This approach yields a significant improvement inaccuracy, especially for the scattered field, where we verified the results against Mie theory. The computation time and memory requirements are about the same as for conventional FDTD. We apply these developments to solve propagation problems in subwavelength structures.

  9. Comparing FDTD and Ray-Tracing Models in Numerical Simulation of HgCdTe LWIR Photodetectors

    Science.gov (United States)

    Vallone, Marco; Goano, Michele; Bertazzi, Francesco; Ghione, Giovanni; Schirmacher, Wilhelm; Hanna, Stefan; Figgemeier, Heinrich

    2016-09-01

    We present a simulation study of HgCdTe-based long-wavelength infrared detectors, focusing on methodological comparisons between the finite-difference time-domain (FDTD) and ray-tracing optical models. We performed three-dimensional simulations to determine the absorbed photon density distributions and the corresponding photocurrent and quantum efficiency spectra of isolated n-on- p uniform-composition pixels, systematically comparing the results obtained with FDTD and ray tracing. Since ray tracing is a classical optics approach, unable to describe interference effects, its applicability has been found to be strongly wavelength dependent, especially when reflections from metallic layers are relevant. Interesting cavity effects around the material cutoff wavelength are described, and the cases where ray tracing can be considered a viable approximation are discussed.

  10. Evaluation of electric and magnetic fields distribution and SAR induced in 3D models of water containers by radiofrequency radiation using FDTD and FEM simulation techniques

    CERN Document Server

    Abdelsamie, Maher A A; Mustafa, Shuhaimi; Hashim, Dzulkifly

    2014-01-01

    In this study, two software packages using different numerical techniques FEKO 6.3 with Finite-Element Method (FEM) and XFDTD 7 with Finite Difference Time Domain Method (FDTD) were used to assess exposure of 3D models of square, rectangular, and pyramidal shaped water containers to electromagnetic waves at 300, 900, and 2400 MHz frequencies. Using the FEM simulation technique, the peak electric field of 25, 4.5, and 2 V/m at 300 MHz and 15.75, 1.5, and 1.75 V/m at 900 MHz were observed in pyramidal, rectangular, and square shaped 3D container models, respectively. The FDTD simulation method confirmed a peak electric field of 12.782, 10.907, and 10.625 V/m at 2400 MHz in the pyramidal, square, and rectangular shaped 3D models, respectively. The study demonstrated an exceptionally high level of electric field in the water in the two identical pyramid shaped 3D models analyzed using the two different simulation techniques. Both FEM and FDTD simulation techniques indicated variations in the distribution of elect...

  11. Finite Difference Time Domain (FDTD) Simulations of Electromagnetic Wave Propagation Using a Spreadsheet

    CERN Document Server

    Ward, D W; Cantarella, Jason; Fu, Joseph H.G.; Kusner, Rob; Sullivan, John M.; Wrinkle, Nancy C.; Cantarella, Jason; Fu, Joseph H.G.; Kusner, Rob; Sullivan, John M.; Wrinkle, Nancy C.; Cantarella, Jason; Fu, Joseph H.G.; Kusner, Rob; Sullivan, John M.; Wrinkle, Nancy C.; Cantarella, Jason; Fu, Joseph H.G.; Kusner, Rob; Sullivan, John M.; Wrinkle, Nancy C.; Gelaki, Shlomo; Ward, David W.; Nelson, Keith A.

    2004-01-01

    We describe a simple and intuitive implementation of the method of finite difference time domain simulations for propagating electromagnetic waves using the simplest possible tools available in Microsoft Excel. The method overcomes the usual obstacles of familiarity with programming languages as it relies on little more than the cut and paste features that are standard in Excel. Avenues of exploration by students are proposed and sample graphs are included. The pedagogical effectiveness of the implementation was tested during an Independent Activities Period class, composed of 80% freshmen, at MIT, and yielded positive results.

  12. Limitation of FDTD in simulation of a perfect lens imaging system.

    Science.gov (United States)

    Chen, Jianbing J; Grzegorczyk, Tomasz M; Wu, Bae-Ian; Kong, Jin Au

    2005-12-26

    The ability of the Finite-Difference Time-Domain method to model a perfect lens made of a slab of homogeneous left-handed material (LHM) is investigated. It is shown that because of the frequency dispersive nature of the medium and the time discretization, an inherent mismatch in the constitutive parameters exists between the slab and its surrounding medium. This mismatch in the real part of the permittivity and permeability is found to have the same order of magnitude as the losses typically used in numerical simulations. Hence, when the LHM slab is lossless, this mismatch is shown to be the main factor contributing to the image resolution loss of the slab. PMID:19503302

  13. Agent Simulation of Chain Bankruptcy

    OpenAIRE

    Yuichi Ikeda; Yoshi Fujiwara; Wataru Souma; Hideaki Aoyama; Hiroshi Iyetomi

    2007-01-01

    We have conducted an agent-based simulation of chain bankruptcy. The propagation of credit risk on a network, i.e., chain bankruptcy, is the key to nderstanding largesized bankruptcies. In our model, decrease of revenue by the loss of accounts payable is modeled by an interaction term, and bankruptcy is defined as a capital deficit. Model parameters were estimated using financial data for 1,077 listed Japanese firms. Simulations of chain bankruptcy on the real transaction network consisting o...

  14. Explaining simulations through self explaining agents

    NARCIS (Netherlands)

    Harbers, M.; Bosch, K. van den; Meyer, J.J.C.

    2010-01-01

    Several strategies are used to explain emergent interaction patterns in agent-based simulations. A distinction can be made between simulations in which the agents just behave in a reactive way, and simulations involving agents with also pro-active (goal-directed) behavior. Pro-active behavior is mor

  15. Explaining Simulations through Self Explaining Agents

    NARCIS (Netherlands)

    Harbers, M.; Dignum, F.; Bosch, K. van den; Meyer, J.J.C.

    2008-01-01

    Several strategies are used to explain emergent interaction patterns in agent-based simulations. A distinction can be made between simulations in which the agents just behave in a reactive way, and simulations involving agents with also pro-active (goal-directed) behavior. Pro-active behavior is mor

  16. Explaining Simulations Through Self Explaining Agents

    OpenAIRE

    Maaike Harbers; John-Jules Meyer; Karel Van den Bosch

    2010-01-01

    Several strategies are used to explain emergent interaction patterns in agent-based simulations. A distinction can be made between simulations in which the agents just behave in a reactive way, and simulations involving agents with also pro-active (goal-directed) behavior. Pro-active behavior is more variable and harder to predict than reactive behavior, and therefore it might be harder to explain. However, the approach presented in this paper tries to make advantage of the agents' pro-active...

  17. Multi-agent systems simulation and applications

    CERN Document Server

    Uhrmacher, Adelinde M

    2009-01-01

    Methodological Guidelines for Modeling and Developing MAS-Based SimulationsThe intersection of agents, modeling, simulation, and application domains has been the subject of active research for over two decades. Although agents and simulation have been used effectively in a variety of application domains, much of the supporting research remains scattered in the literature, too often leaving scientists to develop multi-agent system (MAS) models and simulations from scratch. Multi-Agent Systems: Simulation and Applications provides an overdue review of the wide ranging facets of MAS simulation, i

  18. A multi-band, multi-level, multi-electron model for efficient FDTD simulations of electromagnetic interactions with semiconductor quantum wells

    CERN Document Server

    Ravi, Koustuban; Ho, Seng-Tiong

    2015-01-01

    We report a new computational model for simulations of electromagnetic interactions with semiconductor quantum well(s) (SQW) in complex electromagnetic geometries using the finite difference time domain (FDTD) method. The presented model is based on an approach of spanning a large number of electron transverse momentum states in each SQW sub-band (multi-band) with a small number of discrete multi-electron states (multi-level, multi-electron). This enables accurate and efficient two dimensional (2-D) and 3-D simulations of nanophotonic devices with SQW active media. The model includes the following features: (1) Optically induced interband transitions between various SQW conduction and heavy-hole or light-hole sub-bands are considered. (2) Novel intra sub-band and inter sub-band transition terms are derived to thermalize the electron and hole occupational distributions to the correct Fermi-Dirac distributions. (3) The terms in (2) result in an explicit update scheme which circumvents numerically cumbersome ite...

  19. FDTD Method in the Analysis of Lithium Niobate Modulator

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Mach-Zehnder traveling-wave lithium niobate modulator is simulated by time domain finite difference (FDTD) method for different device geometry. The result is comparable to the reported value by finite element method.

  20. Intelligent Farmer Agent for Multi-Agent Ecological Simulations Optimization

    OpenAIRE

    Filipe Cruz; António Pereira; Pedro Valente; Pedro Duarte; Luis Paulo Reis

    2007-01-01

    This paper presents the development of a bivalve farmer agent interacting with a realistic ecological simulation system. The purpose of the farmer agent is to determine the best combinations of bivalve seeding areas in a large region, maximizing the production without exceeding the total allowed seeding area. A system based on simulated annealing, tabu search, genetic algorithms and reinforcement learning, was developed to minimize the number of iterations required to unravel a semi-optimum s...

  1. Advanced FDTD methods parallelization, acceleration, and engineering applications

    CERN Document Server

    Yu, Wenhua

    2011-01-01

    The finite-difference time-domain (FDTD) method has revolutionized antenna design and electromagnetics engineering. Here's a cutting-edge book that focuses on the performance optimization and engineering applications of FDTD simulation systems. Covering the latest developments in this area, this unique resource offer you expert advice on the FDTD method, hardware platforms, and network systems. Moreover the book offers guidance in distinguishing between the many different electromagnetics software packages on the market today. You also find a complete chapter dedicated to large multi-scale pro

  2. Compound FDTD method for silicon photonics

    Directory of Open Access Journals (Sweden)

    Abbas Olyaee

    2011-09-01

    Full Text Available Attempt to manufacture photonics devices on silicon requires theoretical and numerical prediction. This essay presents Compound FDTD (C-FDTD method for comprehensive simulation of silicon photonics devices. Although this method is comprehensive, it maintains conventional Yee algorithm. The method involves variation of refractive index due to nonlinear effects. With the help of this simulator, refractive index change due to free-carriers created through two photon absorption and Kerr effect in silicon waveguide is considered. Results indicate how to choose pump pulse shape to optimum operation of active photonics devices. Also conductivity variation of Si waveguide due to change in free-carrier density is studied. By considering variations in conductivity profile, we are able to design better schemes for sweep free carriers away with reverse bias or nonlinear photovoltaic effect for fast devices and Raman amplifiers.

  3. FDTD Modeling of Transient Scattering by Subsurface Targets

    Institute of Scientific and Technical Information of China (English)

    Gong Zhu-qian; Zhu Guo-qiang

    2004-01-01

    In this paper, a two-dimensional (2-D) finitedifference time-domain method (FDTD) scheme is used to simulate the transient scattering characteristics of buried objects, which are modeled by columns of arbitrary permittivities, conductivities, and sizes. The FDTD soil is modeled by isotropic, homogeneous and lossy media. The standing-trave-ling wave boundary condition (STWBC) that can simplify calculation and save CPU storage is used for modeling physical absorbers inside the FDTD computational domain. Reflection of electromagnetic pulses incident on a layered medium and transient scattering by the ground and an underground air square cylinder are computed. These results verify the validity of the FDTD scheme by comparisons with those shown in some references. Numerical results presented in the final part of this paper are desirable and meaningful, explicitly distinguishing echo waves stemming from the ground and the buried objects.

  4. Agent-based simulation of animal behaviour

    OpenAIRE

    Jonker, C.M.; Treur, J.

    1998-01-01

    In this paper it is shown how animal behaviour can be simulated in an agent-based manner. Different models are shown for different types of behaviour, varying from purely reactive behaviour to pro-active, social and adaptive behaviour. The compositional development method for multi-agent systems DESIRE and its software environment supports the conceptual and detailed design, and execution of these models. Experiments reported in the literature on animal behaviour have been simulated for a num...

  5. A Revised Piecewise Linear Recursive Convolution FDTD Method for Magnetized Plasmas

    Institute of Scientific and Technical Information of China (English)

    Liu Song; Zhong Shuangying; Liu Shaobin

    2005-01-01

    The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method improves accuracy over the original recursive convolution (RC) FDTD approach and current density convolution (JEC) but retains their advantages in speed and efficiency. This paper describes a revised piecewise linear recursive convolution PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time,enabling the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations of the reflection and transmission coefficients through a magnetized plasma layer. The results show that the revised PLRC-FDTD method has improved the accuracy over the original RC FDTD method and JEC FDTD method.

  6. Intelligent Agents for Interactive Simulation Environments

    OpenAIRE

    Tambe, Milind; Johnson, W. Lewis; Jones, Randolph M.; Koss, Frank; Laird, John E.; Rosenbloom, Paul S.; Schwamb, Karl

    1995-01-01

    Interactive simulation environments constitute one of today's promising emerging technologies, with applications in areas such as education, manufacturing, entertainment, and training. These environments are also rich domains for building and investigating intelligent automated agents, with requirements for the integration of a variety of agent capabilities but without the costs and demands of low-level perceptual processing or robotic control. Our project is aimed at developing humanlike, in...

  7. Multi-Agent Simulation and Management Practices

    CERN Document Server

    Siebers, Peer-Olaf; Celia, Helen; Clegg, Chris

    2010-01-01

    Intelligent agents offer a new and exciting way of understanding the world of work. Agent-Based Simulation (ABS), one way of using intelligent agents, carries great potential for progressing our understanding of management practices and how they link to retail performance. We have developed simulation models based on research by a multi-disciplinary team of economists, work psychologists and computer scientists. We will discuss our experiences of implementing these concepts working with a well-known retail department store. There is no doubt that management practices are linked to the performance of an organisation (Reynolds et al., 2005; Wall & Wood, 2005). Best practices have been developed, but when it comes down to the actual application of these guidelines considerable ambiguity remains regarding their effectiveness within particular contexts (Siebers et al., forthcoming a). Most Operational Research (OR) methods can only be used as analysis tools once management practices have been implemented. Ofte...

  8. Agent Based Modelling for Social Simulation

    NARCIS (Netherlands)

    Smit, S.K.; Ubink, E.M.; Vecht, B. van der; Langley, D.J.

    2013-01-01

    This document is the result of an exploratory project looking into the status of, and opportunities for Agent Based Modelling (ABM) at TNO. The project focussed on ABM applications containing social interactions and human factors, which we termed ABM for social simulation (ABM4SS). During the course

  9. An Agent-Based Monetary Production Simulation Model

    DEFF Research Database (Denmark)

    Bruun, Charlotte

    2006-01-01

    An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable......An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable...

  10. Agent-based modeling and simulation

    CERN Document Server

    Taylor, Simon

    2014-01-01

    Operational Research (OR) deals with the use of advanced analytical methods to support better decision-making. It is multidisciplinary with strong links to management science, decision science, computer science and many application areas such as engineering, manufacturing, commerce and healthcare. In the study of emergent behaviour in complex adaptive systems, Agent-based Modelling & Simulation (ABMS) is being used in many different domains such as healthcare, energy, evacuation, commerce, manufacturing and defense. This collection of articles presents a convenient introduction to ABMS with pa

  11. A High-Performance Parallel FDTD Method Enhanced by Using SSE Instruction Set

    Directory of Open Access Journals (Sweden)

    Dau-Chyrh Chang

    2012-01-01

    Full Text Available We introduce a hardware acceleration technique for the parallel finite difference time domain (FDTD method using the SSE (streaming (single instruction multiple data SIMD extensions instruction set. The implementation of SSE instruction set to parallel FDTD method has achieved the significant improvement on the simulation performance. The benchmarks of the SSE acceleration on both the multi-CPU workstation and computer cluster have demonstrated the advantages of (vector arithmetic logic unit VALU acceleration over GPU acceleration. Several engineering applications are employed to demonstrate the performance of parallel FDTD method enhanced by SSE instruction set.

  12. FDTD numerical simulation of the trapping force of microsphere in single optical tweezers%时域有限差分法数值仿真单光镊中微球受到的光阱力

    Institute of Scientific and Technical Information of China (English)

    胡耿军; 李静; 龙潜; 陶陶; 张恭轩; 伍小平

    2011-01-01

    In this paper the model of trapping force on microsphere near focus in single optical tweezers is built by three dimensional finite-difference time-domain (FDTD) and Maxwell stress tensor methods. Fifth order Gaussian beam based on spherical vector wave function (VSWF) is adopted as simulation light source; the correct light field transmission is obtained. The influences of the wavelength, waist and polarization of light sources, the radius and refractive index of the microsphere on the optical trapping force are discussed. The influence of nearby microsphere and beam polarization on the trapping force of the trapped microsphere in single optical tweezers is analyzed. The effect of beam polarization working on the trapping force of the trapped microsphere is specially analyzed. As results of simulation, the trapping force acting on the microsphere by the circularly polarized beam is larger than that by the linearly polarized beam. The stability of the trapped microsphere in single optical tweezers will be disturbed by the nearby microsphere and lose its balance. Varying the beam polarization will lead to the.change of the trapping force of the trapped microsphere.%本文采用三维时域有限差分法(FDTD)和Maxwell应力张量法建立了单光镊在焦点附近俘获球形微粒的光阱力模型,采用基于球矢量波函数(VSWF)的五阶高斯光源作为仿真光源,得到了准确的光场传播.讨论了光源的波长、束腰、偏振态和微球的半径、折射率对光阱力的影响,分析了在单光镊俘获微球时,邻近微球对光阱力的影响.特别研究了光源的偏振态对微球所受光阱力的作用效果,仿真结果表明圆偏振光比线偏振光对微球的俘获力更大;被光镊稳定俘获的微球,会受到邻近微球干扰,失去平衡状态,改变光源的偏振态可以改变微球的受力状态.

  13. FDTD-SPICE for Characterizing Metamaterials Integrated with Electronic Circuits

    Directory of Open Access Journals (Sweden)

    Zhengwei Hao

    2012-01-01

    Full Text Available A powerful time-domain FDTD-SPICE simulator is implemented and applied to the broadband analysis of metamaterials integrated with active and tunable circuit elements. First, the FDTD-SPICE modeling theory is studied and details of interprocess communication and hybridization of the two techniques are discussed. To verify the model, some simple cases are simulated with results in both time domain and frequency domain. Then, simulation of a metamaterial structure constructed from periodic resonant loops integrated with lumped capacitor elements is studied, which demonstrates tuning resonance frequency of medium by changing the capacitance of the integrated elements. To increase the bandwidth of the metamaterial, non-Foster transistor configurations are integrated with the loops and FDTD-SPICE is applied to successfully bridge the physics of electromagnetic and circuit topologies and to model the whole composite structure. Our model is also applied to the design and simulation of a metasurface integrated with nonlinear varactors featuring tunable reflection phase characteristic.

  14. Interfacial Numerical Dispersion and New Conformal FDTD Method

    CERN Document Server

    Fisher, Axman

    2011-01-01

    This article shows the interfacial relation in electrodynamics shall be corrected in discrete grid form which can be seen as certain numerical dispersion beyond the usual bulk type. Further we construct a lossy conductor model to illustrate how to simulate more general material other than traditional PEC or simple dielectrics, by a new conformal FDTD method which main considers the effects of penetrative depth and the distribution of free bulk electric charge and current.

  15. A generic testing framework for agent-based simulation models

    OpenAIRE

    Gürcan, Önder; Dikenelli, Oguz; Bernon, Carole

    2013-01-01

    International audience Agent-based modelling and simulation (ABMS) had an increasing attention during the last decade. However, the weak validation and verification of agent-based simulation models makes ABMS hard to trust. There is no comprehensive tool set for verification and validation of agent-based simulation models, which demonstrates that inaccuracies exist and/or reveals the existing errors in the model. Moreover, on the practical side, many ABMS frameworks are in use. In this sen...

  16. Agent-based Simulation of the Maritime Domain

    Directory of Open Access Journals (Sweden)

    O. Vaněk

    2010-01-01

    Full Text Available In this paper, a multi-agent based simulation platform is introduced that focuses on legitimate and illegitimate aspects of maritime traffic, mainly on intercontinental transport through piracy afflicted areas. The extensible architecture presented here comprises several modules controlling the simulation and the life-cycle of the agents, analyzing the simulation output and visualizing the entire simulated domain. The simulation control module is initialized by various configuration scenarios to simulate various real-world situations, such as a pirate ambush, coordinated transit through a transport corridor, or coastal fishing and local traffic. The environmental model provides a rich set of inputs for agents that use the geo-spatial data and the vessel operational characteristics for their reasoning. The agent behavior model based on finite state machines together with planning algorithms allows complex expression of agent behavior, so the resulting simulation output can serve as a substitution for real world data from the maritime domain.

  17. Crosstalk in modern on-chip interconnects a FDTD approach

    CERN Document Server

    Kaushik, B K; Patnaik, Amalendu

    2016-01-01

    The book provides accurate FDTD models for on-chip interconnects, covering most recent advancements in materials and design. Furthermore, depending on the geometry and physical configurations, different electrical equivalent models for CNT and GNR based interconnects are presented. Based on the electrical equivalent models the performance comparison among the Cu, CNT and GNR-based interconnects are also discussed in the book. The proposed models are validated with the HSPICE simulations. The book introduces the current research scenario in the modeling of on-chip interconnects. It presents the structure, properties, and characteristics of graphene based on-chip interconnects and the FDTD modeling of Cu based on-chip interconnects. The model considers the non-linear effects of CMOS driver as well as the transmission line effects of interconnect line that includes coupling capacitance and mutual inductance effects. In a more realistic manner, the proposed model includes the effect of width-dependent MFP of the ...

  18. Integrating Encrypted Mobile Agents with Smart Spaces in a Multi-agent Simulator for Resource Management

    OpenAIRE

    Sherin M. Moussa; Gul A. Agha

    2010-01-01

    The existence of advanced smart devices and related technologies such as pervasive computing, mobile wireless communications, sensor networks and agent technologies have supported the proliferation of smart spaces. In this paper, we present the design of “Bosthan”, a multi-agent-based simulation tool that manages resources consumption in multi-inhabitants smart spaces. Bosthan is built on the top of ActorNet mobile agent platform to simulate different smart space topologies with varying numbe...

  19. The Gap of Current Agent Based Simulation Modeling Practices and Feasibility of a Generic Agent Based Simulation Model

    OpenAIRE

    Yim Ling Loo; Alicia Y.C. Tang; Azhana Ahmad

    2015-01-01

    Agent-based modeling had been revolving to be established approach in modeling simulation systems which are used to understand and predict certain real-life scenarios in specific domains. Past researches which are domain-specific caused repetitive building of new models from scratch and restrict replication and reuse because of limitation of models’ description. This paper presents a review of gaps between domain-specific agent-based simulation modeling and the recent practices of agent-based...

  20. Joint FDTD-Optical/FEM-Electrical Numerical Simulation of Reflection-Type Subwavelength-Microstructure InSb Infrared Focal-Plane Arrays

    Science.gov (United States)

    He, J. L.; Hu, W. D.; Ye, Z. H.; Lv, Y. Q.; Chen, X. S.; Lu, W.

    2016-05-01

    The design of a reflection-type subwavelength microstructure has been numerically investigated to concentrate incident light onto pixels for improved photoresponse of InSb infrared focal-plane arrays. Compared with traditional microlenses placed on top of the detector substrate, this reflection-type microstructure is better suited for extremely small pixel pitches. The structure is simulated using a joint numerical method combining the finite-difference time-domain method based on Maxwell's curl equations and the finite-element method based on the Poisson and continuity equations. The results show that this advanced design could effectively improve device response without sacrificing crosstalk. The optimal structure parameters are obtained theoretically, with response increase of approximately 100%.

  1. Modeling and simulation of complex systems a framework for efficient agent-based modeling and simulation

    CERN Document Server

    Siegfried, Robert

    2014-01-01

    Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard

  2. Determination of the transmission coefficients for quantum structures using FDTD method.

    Science.gov (United States)

    Peng, Yangyang; Wang, Xiaoying; Sui, Wenquan

    2011-12-01

    The purpose of this work is to develop a simple method to incorporate quantum effect in traditional finite-difference time-domain (FDTD) simulators. Witch could make it possible to co-simulate systems include quantum structures and traditional components. In this paper, tunneling transmission coefficient is calculated by solving time-domain Schrödinger equation with a developed FDTD technique, called FDTD-S method. To validate the feasibility of the method, a simple resonant tunneling diode (RTD) structure model has been simulated using the proposed method. The good agreement between the numerical and analytical results proves its accuracy. The effectness and accuracy of this approach makes it a potential method for analysis and design of hybrid systems includes quantum structures and traditional components. PMID:22409063

  3. Agent Based Modelling and Simulation of Social Processes

    OpenAIRE

    Armano Srbljinovic; Ognjen Skunca

    2003-01-01

    The paper provides an introduction to agent-based modelling and simulation of social processes. Reader is introduced to the worldview underlying agent-based models, some basic terminology, basic properties of agent-based models, as well as to what one can and what cannot expect from such models, particularly when they are applied to social-scientific investigation. Special attention is given to the issues of validation. Classification-ACM-1998: J.4 [Computer Applications]; Social and behavior...

  4. Container Terminal Operations Modeling through Multi agent based Simulation

    OpenAIRE

    Ayub, Yasir; Faruki, Usman

    2009-01-01

    This thesis aims to propose a multi-agent based hierarchical model for the operations of container terminals. We have divided our model into four key agents that are involved in each sub processes. The proposed agent allocation policies are recommended for different situations that may occur at a container terminal. A software prototype is developed which implements the hierarchical model. This web based application is used in order to simulate the various processes involved in the following ...

  5. TACOP: A cognitive agent for a naval training simulation environment

    OpenAIRE

    Doesburg, van, P.H.; Heuvelink, Annerieke; Broek, van den, PR Peter; Dignum, F.; Dignum, V.; Koendig, S.; Kraus, S.; Pechoucek, M.; Singh, M.; Steiner, D; Thompson, S.; Wooldridge, M.

    2005-01-01

    This paper describes how cognitive modeling can be exploited in the design of software agents that support naval training sessions. The architecture, specifications, and embedding of the cognitive agent in a simulation environment are described. Subsequently, the agent’s functioning was evaluated in complex, real life training situations for naval officers.

  6. Evolution of cooperative behavior in simulation agents

    Energy Technology Data Exchange (ETDEWEB)

    Stroud, P.D.

    1998-04-01

    A simulated automobile factory paint shop is used as a testbed for exploring the emulation of human decision making behavior. A discrete events simulation of the paint shop as a collection of interacting Java actors is described. An evolutionary cognitive architecture is under development for building software actors to emulate humans in simulations of human dominated complex systems. In this paper, the cognitive architecture is extended by implementing a persistent population of trial behaviors with an incremental fitness valuation update strategy, and by allowing a group of cognitive actors to share information. A proof of principle demonstration is presented.

  7. Intelligent agent supported training in virtual simulations

    NARCIS (Netherlands)

    Heuvelink, A.; Bosch, K. van den; Doesburg, W.A. van; Harbers, M.

    2009-01-01

    Simulation-based training in military decision making often requires ample personnel for playing various roles (e.g. team mates, adversaries). Usually humans are used to play these roles to ensure varied behavior required for the training of such tasks. However, there is growing conviction and evide

  8. Specialized Multicore Architectures Supporting Efficient Multi-Agent Simulations

    Directory of Open Access Journals (Sweden)

    Wolfgang Heenes

    2011-07-01

    Full Text Available Two new multiprocessor architectures to accelerate the simulation of multi-agent systems based on the massively parallel GCA (Global Cellular Automata model are presented. The GCA model is suited to describe and simulate different multi-agent systems. The designed and implemented architectures mainly consist of a set of processors (NIOS II and a network. The multiprocessor systems allow the implementation in a flexible way through programming, thus simulating different behaviors on the same architecture. Two architectures, one with up to 16 processors, were implemented on an FPGA. The first architecture uses hardware hash functions in order to reduce the overall simulation time, but lacks scalability. The second architecture uses an agent memory and a cell field memory. This improves the scalability and further increases the performance.

  9. A decontamination study of simulated chemical and biological agents

    International Nuclear Information System (INIS)

    A comprehensive decontamination scheme of the chemical and biological agents, including airborne agents and surface contaminating agents, is presented. When a chemical and biological attack occurs, it is critical to decontaminate facilities or equipments to an acceptable level in a very short time. The plasma flame presented here may provide a rapid and effective elimination of toxic substances in the interior air in isolated spaces. As an example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies air with an airflow rate of 5000 l/min contaminated with toluene, the simulated chemical agent, and soot from a diesel engine, the simulated aerosol for biological agents. Although the airborne agents in an isolated space are eliminated to an acceptable level by the plasma flame, the decontamination of the chemical and biological agents cannot be completed without cleaning surfaces of the facilities. A simulated sterilization study of micro-organisms was carried out using the electrolyzed ozone water. The electrolyzed ozone water very effectively kills endospores of Bacillus atrophaeus (ATCC 9372) within 3 min. The electrolyzed ozone water also kills the vegetative micro-organisms, fungi, and virus. The electrolyzed ozone water, after the decontamination process, disintegrates into ordinary water and oxygen without any trace of harmful materials to the environment

  10. Cognitive Modeling for Agent-Based Simulation of Child Maltreatment

    Science.gov (United States)

    Hu, Xiaolin; Puddy, Richard

    This paper extends previous work to develop cognitive modeling for agent-based simulation of child maltreatment (CM). The developed model is inspired from parental efficacy, parenting stress, and the theory of planned behavior. It provides an explanatory, process-oriented model of CM and incorporates causality relationship and feedback loops from different factors in the social ecology in order for simulating the dynamics of CM. We describe the model and present simulation results to demonstrate the features of this model.

  11. Analyzing the ENRON Communication Network Using Agent-Based Simulation

    Directory of Open Access Journals (Sweden)

    Shinako Matsuyama

    2008-07-01

    Full Text Available Agent-based modeling, simulation, and network analysis approaches are one of the emergent techniques among soft computing literature. This paper presents an agent-based model for analyzing the characteristics of peer-to-peer human communication networks. We focus on the process of the collapse of Enron Corporation, which is an interesting topic among the business management domain. The Enron email dataset is available for the analysis. Our approach consists of the four steps: First, macro-level characteristics of the Enron email dataset is analyzed from the viewpoints of social network theory: (i the degrees of the communication networks and contents information, and (ii the changes of network structures among the major events. Second, for the micro-level analysis, an agent-based simulator is implemented using the Enron email dataset. Third, both micro- and macro- level characteristics are calculated on the simulator to ground the model to the dataset. Finally, a different artificial society from the Enron email dataset is developed the simulator and we compare its characteristics of communication patterns with the result of the ones in the agent-based simulation with the Enron email dataset. The investigation suggests that the agent-based model is beneficial to uncover the characteristics of implicit communication mechanisms of the firm.

  12. Agent-Based Simulations for Project Management

    Science.gov (United States)

    White, J. Chris; Sholtes, Robert M.

    2011-01-01

    Currently, the most common approach used in project planning tools is the Critical Path Method (CPM). While this method was a great improvement over the basic Gantt chart technique being used at the time, it now suffers from three primary flaws: (1) task duration is an input, (2) productivity impacts are not considered , and (3) management corrective actions are not included. Today, computers have exceptional computational power to handle complex simulations of task e)(eculion and project management activities (e.g ., dynamically changing the number of resources assigned to a task when it is behind schedule). Through research under a Department of Defense contract, the author and the ViaSim team have developed a project simulation tool that enables more realistic cost and schedule estimates by using a resource-based model that literally turns the current duration-based CPM approach "on its head." The approach represents a fundamental paradigm shift in estimating projects, managing schedules, and reducing risk through innovative predictive techniques.

  13. Agent-Based Approaches for Behavioural Modelling in Military Simulations

    Directory of Open Access Journals (Sweden)

    Gaurav Chaudhary

    2015-12-01

    Full Text Available Behavioral modeling of combat entities in military simulations by creating synthetic agents in order to satisfy various battle scenarios is an important problem. The conventional modeling tools are not always sufficient to handle complex situations requiring adaptation. To deal with this Agent-Based Modeling (ABM is employed, as the agents exhibit autonomous behavior by adapting and varying their behavior during the course of the simulation whilst achieving the goals. Synthetic agents created by means of Computer Generated Force (CGF is a relatively recent approach to model behavior of combat entities for a more realistic training and effective military planning. CGFs, are also sometimes referred to as Semi- Automated Forces (SAF and enables to create high-fidelity simulations. Agents are used to control and augment the behavior of CGF entities, hence converting them into Intelligent CGF (ICGF. The intelligent agents can be modeled to exhibit cognitive abilities. For this review paper, extensive papers on stateof-the-art in agent-based modeling approaches and applications were surveyed. The paper assimilates issues involved in ABM with CGF as an important component of it. It reviews modeling aspects with respect to the interrelationship between ABM and CGF, which is required to carry out behavioral modeling. Important CGFs have been examined and a list with their significant features is given. Another issue that has been reviewed is that how the synthetic agents having different capabilities are implemented at different battle levels. Brief mention of state-of-the-art integrated cognitive architectures and a list of significant cognitive applications based on them with their features is given. At the same time, the maturity of ABM in agent-based applications has also been considered.

  14. DESIGN OF A SOFTWARE AGENT FOR BUSINESS GAMING SIMULATION

    Institute of Scientific and Technical Information of China (English)

    Yuji SHINODA; Mina RYOKE; Takao TERANO; Yoshiteru NAKAMORI

    2006-01-01

    This paper introduces a software agent as a virtual player of the business game called Bakery Game.The business game is a tool to understand business and management principles through experience in a virtual world. In order to construct software agents for the gaming simulation, which is able to participate in a game and become human players' worthy rival, we combine a simple model that considers the property of Bakery Game with a strategy adjustment model. The agent has so-called strategy parameters that are updated through the experience. The agent changes his strategy depending on particular situation. The agent participates in the game that is regenerated from log data in various situations.

  15. GENETIC ALGORITHM IN REDUCTION OF NUMERICAL DISPERSION OF 3-D ADI-FDTD METHOD

    Institute of Scientific and Technical Information of China (English)

    Zhang Yan; Lǖ Shanwei; Gao Wenjun

    2007-01-01

    A new method to reduce the numerical dispersion of the three-dimensional Alternating Direction Implicit Finite-Difference Time-Domain(3-D ADI-FDTD)method is proposed.Firstly,the numerical formulations of the 3-D ADI-FDTD method are modified with the artificial anisotropy,and the new numerical dispersion relation is derived.Secondly,the relative permittivity tensor of the artificial anisotropy can be obtained by the Adaptive Genetic Algorithm(AGA).In order to demonstrate the accuracy and efficiency of this new method,a monopole antenna is simulated as an example.And the numerical results and the computational requirements of the proposed method are cornpared with those of the conventional ADI-FDTD method and the measured data.In addition the reduction of the numerical dispersion is investigated as the objective function of the AGA.It is found that this new method is accurate and efficient by choosing proper objective function.

  16. FDTD COMPUTATION FOR SAR INDUCED IN HUMAN HEAD DUE TO EXPOSURE TO EMF FROM MOBILE PHONE

    Directory of Open Access Journals (Sweden)

    Ashraf A. Aly

    2014-12-01

    Full Text Available This aim of this paper is to investigate the specific absorption rate (SAR distribution in a human head by using the finite-difference time-domain (FDTD calculations, due to exposure to EMF radiation from a mobile phone at frequencies 900 MHz Mobile Phone model with a λ/2 monopole antenna and a hand head phone model dimensions are 100 mm x 50 mm x 20 mm. The head model used is a sphere with a diameter of 18 cm. The FDTD grid size used in the computation was 2.5 mm. The distance between the antenna and head was 5 mm. To simplify the FDTD simulation, the SAR in the head was calculated without the effect of the human body. It was found that the SAR induced in the head decreases with the distance from the radiating source

  17. Using cheminformatics to find simulants for chemical warfare agents

    International Nuclear Information System (INIS)

    Highlights: → Summary of chemical warfare agent (CWA) simulants in current use. → Application of method of molecular similarity to CWA and simulants. → Quantitative metric for CWA-simulant similarity. → Rank ordering of simulants in current use. → Potential of method to identify simulants for emerging agents. - Abstract: Direct experimentation with chemical warfare agents (CWA) to study important problems such as their permeation across protective barrier materials, decontamination of equipment and facilities, or the environmental transport and fate of CWAs is not feasible because of the obvious toxicity of the CWAs and associated restrictions on their laboratory use. The common practice is to use 'simulants,' namely, analogous chemicals that closely resemble the CWAs but are less toxic, with the expectation that the results attained for simulants can be correlated to how the CWAs would perform. Simulants have been traditionally chosen by experts, by means of intuition, using similarity in one or more physical properties (such as vapor pressure or aqueous solubility) or in the molecular structural features (such as functional groups) between the stimulant and the CWA. This work is designed to automate the simulant identification process backed by quantitative metrics, by means of chemical similarity search software routinely used in pharmaceutical drug discovery. The question addressed here is: By the metrics of such software, how similar are traditional simulants to CWAs? That is, what is the numerical 'distance' between each CWA and its customary simulants in the quantitative space of molecular descriptors? The answers show promise for finding close but less toxic simulants for the ever-increasing numbers of CWAs objectively and fast.

  18. Modeling and simulating human teamwork behaviors using intelligent agents

    Science.gov (United States)

    Fan, Xiaocong; Yen, John

    2004-12-01

    Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive problems. Teamwork modeling is also challenging because the research has spanned diverse disciplines from business management to cognitive science, human discourse, and distributed artificial intelligence. This article presents an extensive, but not exhaustive, list of work in the field, where the taxonomy is organized along two main dimensions: team social structure and social behaviors. Along the dimension of social structure, we consider agent-only teams and mixed human-agent teams. Along the dimension of social behaviors, we consider collaborative behaviors, communicative behaviors, helping behaviors, and the underpinning of effective teamwork-shared mental models. The contribution of this article is that it presents an organizational framework for analyzing a variety of teamwork simulation systems and for further studying simulated teamwork behaviors.

  19. Operational-level naval planning using agent-based simulation

    OpenAIRE

    Ercetin, Askin.

    2001-01-01

    This thesis uses agent-based modeling techniques to develop a simulation of the operational-level naval planning process. The simulation serves as an initial exploratory laboratory for analyzing the consequences of the force allocation, force deployment, and force movement decisions made by operational-level naval commanders during times of conflict or crisis. This model will hopefully help decision-makers in gaining insight into the naval planning process and enable them to make more informe...

  20. An Agent Based Simulation Of Smart Metering Technology Adoption

    OpenAIRE

    Zhang,Tao; Nuttall, William J.

    2007-01-01

    Based on the classic behavioural theory ?the Theory of Planned Behaviour?, we develop an agent-based model to simulate the diffusion of smart metering technology in the electricity market. We simulate the emergent adoption of smart metering technology under different management strategies and economic regulations. Our research results show that in terms of boosting the take-off of smart meters in the electricity market, choosing the initial users on a random and geographically dispersed basis...

  1. Agent 2003 Conference on Challenges in Social Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Margaret Clemmons, ed.

    2003-01-01

    Welcome to the Proceedings of the fourth in a series of agent simulation conferences cosponsored by Argonne National Laboratory and The University of Chicago. Agent 2003 is the second conference in which three Special Interest Groups from the North American Association for Computational Social and Organizational Science (NAACSOS) have been involved in planning the program--Computational Social Theory; Simulation Applications; and Methods, Toolkits and Techniques. The theme of Agent 2003, Challenges in Social Simulation, is especially relevant, as there seems to be no shortage of such challenges. Agent simulation has been applied with increasing frequency to social domains for several decades, and its promise is clear and increasingly visible. Like any nascent scientific methodology, however, it faces a number of problems or issues that must be addressed in order to progress. These challenges include: (1) Validating models relative to the social settings they are designed to represent; (2) Developing agents and interactions simple enough to understand but sufficiently complex to do justice to the social processes of interest; (3) Bridging the gap between empirically spare artificial societies and naturally occurring social phenomena; (4) Building multi-level models that span processes across domains; (5) Promoting a dialog among theoretical, qualitative, and empirical social scientists and area experts, on the one hand, and mathematical and computational modelers and engineers, on the other; (6) Using that dialog to facilitate substantive progress in the social sciences; and (7) Fulfilling the aspirations of users in business, government, and other application areas, while recognizing and addressing the preceding challenges. Although this list hardly exhausts the challenges the field faces, it does identify topics addressed throughout the presentations of Agent 2003. Agent 2003 is part of a much larger process in which new methods and techniques are applied to

  2. Tutorial on agent-based modeling and simulation. Part 2 : how to model with agents.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2006-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of interacting autonomous agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to do research. Some have gone so far as to contend that ABMS is a new way of doing science. Computational advances make possible a growing number of agent-based applications across many fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling the growth and decline of ancient civilizations to modeling the complexities of the human immune system, and many more. This tutorial describes the foundations of ABMS, identifies ABMS toolkits and development methods illustrated through a supply chain example, and provides thoughts on the appropriate contexts for ABMS versus conventional modeling techniques.

  3. Tutorial on agent-based modeling and simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2005-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS is a third way of doing science besides deductive and inductive reasoning. Computational advances have made possible a growing number of agent-based applications in a variety of fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling consumer behavior to understanding the fall of ancient civilizations, to name a few. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing ABMS models, and provides some thoughts on the relationship between ABMS and traditional modeling techniques.

  4. Return Migration After Brain Drain: An Agent Based Simulation Approach

    CERN Document Server

    Biondo, A E; Rapisarda, A

    2012-01-01

    The Brain Drain phenomenon is particularly heterogeneous and is characterized by peculiar specifications. It influences the economic fundamentals of both the country of origin and the host one in terms of human capital accumulation. Here, the brain drain is considered from a microeconomic perspective: more precisely we focus on the individual rational decision to return, referring it to the social capital owned by the worker. The presented model, restricted to the case of academic personnel, compares utility levels to justify agent's migration conduct and to simulate several scenarios with a NetLogo agent based model. In particular, we developed a simulation framework based on two fundamental individual features, i.e. risk aversion and initial expectation, which characterize the dynamics of different agents according to the random evolution of their personal social networks. Our main result is that, according to the value of risk aversion and initial expectation, the probability of return migration depends on...

  5. Simulation of convoy of unmanned vehicles using agent based modeling

    Science.gov (United States)

    Sharma, Sharad; Singh, Harpreet; Gerhart, G. R.

    2007-10-01

    There has been an increasing interest of unmanned vehicles keeping the importance of defense and security. A few models for a convoy of unmanned vehicle exist in literature. The objective of this paper is to exploit agent based modeling technique for a convoy of unmanned vehicles where each vehicle is an agent. Using this approach, the convoy of vehicles reaches a specified goal from a starting point. Each agent is associated with number of sensors. The agents make intelligent decisions based on sensor inputs and at the same time maintaining their group capability and behavior. The simulation is done for a battlefield environment from a single starting point to a single goal. This approach can be extended for multiple starting points to reach multiple goals. The simulation gives the time taken by the convoy to reach a goal from its initial position. In the battlefield environment, commanders make various tactical decisions depending upon the location of an enemy outpost, minefields, number of soldiers in platoons, and barriers. The simulation can help the commander to make effective decisions depending on battlefield, convoy and obstacles to reach a particular goal. The paper describes the proposed approach and gives the simulation results. The paper also gives problems for future research in this area.

  6. Engineering Agent-Based Social Simulations: An Introduction

    OpenAIRE

    Peer-Olaf Siebers; Paul Davidsson

    2015-01-01

    This special section on "Engineering Agent-Based Social Simulations" aims to represent the current state of the art in using Software Engineering (SE) methods in ABSS. It includes a mixture of theoretically oriented papers that describe frameworks, notations and methods adapted from SE and practice-oriented papers that demonstrate the application of SE methods in real world ABSS projects.

  7. Agent-based analysis of organizations : formalization and simulation

    OpenAIRE

    Dignum, M.V.; Tick, C.

    2008-01-01

    Organizational effectiveness depends on many factors, including individual excellence, efficient structures, effective planning and capability to understand and match context requirements. We propose a way to model organizational performance based on a combination of formal models and agent-based simulation that supports the analysis of the congruence of different organizational structures to changing environments

  8. Complete agent based simulation of mini-grids

    OpenAIRE

    González de Durana García, José María; Barambones Caramazana, Oscar; Kremers, Enrique; Viejo, Pablo

    2009-01-01

    EuroPES 2009 With eyes focused on simulation we review some of the main topics of Hybrid Renewable Energy Systems (HRES). Then we describe an Agent Based model of a simple example of one of such systems, a micro-grid, oriented to designing a decentralized Supervisor Control. The model has been implemented using AnyLogic.

  9. FDTD analysis of the light extraction efficiency of OLEDs with a random scattering layer.

    Science.gov (United States)

    Kim, Jun-Whee; Jang, Ji-Hyang; Oh, Min-Cheol; Shin, Jin-Wook; Cho, Doo-Hee; Moon, Jae-Hyun; Lee, Jeong-Ik

    2014-01-13

    The light extraction efficiency of OLEDs with a nano-sized random scattering layer (RSL-OLEDs) was analyzed using the Finite Difference Time Domain (FDTD) method. In contrast to periodic diffraction patterns, the presence of an RSL suppresses the spectral shift with respect to the viewing angle. For FDTD simulation of RSL-OLEDs, a planar light source with a certain spatial and temporal coherence was incorporated, and the light extraction efficiency with respect to the fill factor of the RSL and the absorption coefficient of the material was investigated. The design results were compared to the experimental results of the RSL-OLEDs in order to confirm the usefulness of FDTD in predicting experimental results. According to our FDTD simulations, the light confined within the ITO-organic waveguide was quickly absorbed, and the absorption coefficients of ITO and RSL materials should be reduced in order to obtain significant improvement in the external quantum efficiency (EQE). When the extinction coefficient of ITO was 0.01, the EQE in the RSL-OLED was simulated to be enhanced by a factor of 1.8. PMID:24515010

  10. A Multi-Agent Simulation of Retail Management Practices

    CERN Document Server

    Siebers, Peer-Olaf; Celia, Helen; Clegg, Christopher

    2008-01-01

    We apply Agent-Based Modeling and Simulation (ABMS) to investigate a set of problems in a retail context. Specifically, we are working to understand the relationship between human resource management practices and retail productivity. Despite the fact we are working within a relatively novel and complex domain, it is clear that intelligent agents do offer potential for developing organizational capabilities in the future. Our multi-disciplinary research team has worked with a UK department store to collect data and capture perceptions about operations from actors within departments. Based on this case study work, we have built a simulator that we present in this paper. We then use the simulator to gather empirical evidence regarding two specific management practices: empowerment and employee development.

  11. Agent-based modeling and simulation Part 3 : desktop ABMS.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2007-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS 'is a third way of doing science,' in addition to traditional deductive and inductive reasoning (Axelrod 1997b). Computational advances have made possible a growing number of agent-based models across a variety of application domains. Applications range from modeling agent behavior in the stock market, supply chains, and consumer markets, to predicting the spread of epidemics, the threat of bio-warfare, and the factors responsible for the fall of ancient civilizations. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing agent models, and illustrates the development of a simple agent-based model of shopper behavior using spreadsheets.

  12. Agent-based Simulation of Processes in Medicine

    Czech Academy of Sciences Publication Activity Database

    Bošanský, Branislav

    Praha : Ústav informatiky AV ČR, v. v. i. & MATFYZPRESS, 2008 - (Hakl, F.), s. 19-27 ISBN 978-80-7378-054-8. [Doktorandské dny 2008 Ústavu informatiky AV ČR, v. v. i.. Jizerka (CZ), 29.09.2008-01.10.2008] R&D Projects: GA MŠk(CZ) 1M06014 Institutional research plan: CEZ:AV0Z10300504 Keywords : multi - agent system s * agent -based simulation * process modelling * medicine Subject RIV: IN - Informatics, Computer Science

  13. Efficient Parallel LOD- FDTD method for Debye-Dispersive Media

    OpenAIRE

    Tadashi, Hemmi; Costen, Fumie; Garcia, Salvador; HIMENO, Ryutaro; Yokota, Hideo; Mustafa, Mehshan

    2014-01-01

    The Locally One-Dimensional Finite Difference Time Domain (LOD-FDTD) method is a promising implicit technique for solving Maxwell's Equations in numerical electromagnetics. This paper describes an efficient Message Passing Interface (MPI)-parallel implementation of the LOD-FDTD method for Debye-dispersive media. Its computational efficiency is demonstrated to be superior to that of the parallel ADI-FDTD method. We demonstrate the effectiveness of the proposed parallel algorithm in the si...

  14. Enhancing Multi-Agent Based Simulation with Human-Agents Interactive Spatial Behaviour

    CERN Document Server

    Chen, Yee Ming; Shiu, Hung-Ming

    2009-01-01

    We are exploring the enhancement of models of agent behaviour with more "human-like" decision making strategies than are presently available. Our motivation is to developed with a view to as the decision analysis and support for electric taxi company under the mission of energy saving and reduction of CO2, in particular car-pool and car-sharing management policies. In order to achieve the object of decision analysis for user, we provide a human-agents interactive spatial behaviour to support user making decision real time. We adopt passenger average waiting time and electric taxi average idle time as the performance measures and decision support fro electric taxi company. Finally, according to the analysis result, we demonstrate that our multi-agent simulation and GUI can help users or companies quickly make a quality and accurate decision to reduce the decision-making cost and time.

  15. Simulation of multi-agent manufacturing systems using agent-based modelling platforms

    OpenAIRE

    Barbosa, José; Leitão, Paulo

    2011-01-01

    Multi-agent systems (MAS) are driving the way to design and engineer control solutions that exhibit flexibility, adaptation and reconfigurability, which are important advantages over traditional centralized systems. The understanding, design and testing of such distributed agentbased approaches, and particularly those exhibiting self-* properties, are usually a hard task. Simulation assumes a crucial role to analyse the behaviour of MAS solutions during the design phase and before its deploym...

  16. Agent-based simulation of electricity markets : a literature review

    International Nuclear Information System (INIS)

    The electricity sector in Europe and North America is undergoing considerable changes as a result of deregulation, issues related to climate change, and the integration of renewable resources within the electricity grid. This article reviewed agent-based simulation methods of analyzing electricity markets. The paper provided an analysis of research currently being conducted on electricity market designs and examined methods of modelling agent decisions. Methods of coupling long term and short term decisions were also reviewed. Issues related to single and multiple market analysis methods were discussed, as well as different approaches to integrating agent-based models with models of other commodities. The integration of transmission constraints within agent-based models was also discussed, and methods of measuring market efficiency were evaluated. Other topics examined in the paper included approaches to integrating investment decisions, carbon dioxide (CO2) trading, and renewable support schemes. It was concluded that agent-based models serve as a test bed for the electricity sector, and will help to provide insights for future policy decisions. 74 refs., 6 figs

  17. Robot soccer simulation competition platform based on multi-agent

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents the robot soccer software simulation platform to be firstly used at FIRA Robot World Cup China 2001, introduces the system's purpose and design plan; discusses the system core-server configuration and working principle; describes the operating method and how to develop competition strategy, and refers to the teams to take part in FIRA Robot World Cup China 2001 and investigators who are interested in the distribu ted multi-agent system.

  18. Analysis of equivalent antenna based on FDTD method

    Institute of Scientific and Technical Information of China (English)

    Yun-xing YANG; Hui-chang ZHAO; Cui DI

    2014-01-01

    An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD) method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is air)takes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

  19. Analysis of equivalent antenna based on FDTD method

    Directory of Open Access Journals (Sweden)

    Yun-xing Yang

    2014-09-01

    Full Text Available An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is airtakes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

  20. FDTD for Hydrodynamic Electron Fluid Maxwell Equations

    Directory of Open Access Journals (Sweden)

    Yingxue Zhao

    2015-05-01

    Full Text Available In this work, we develop a numerical method for solving the three dimensional hydrodynamic electron fluid Maxwell equations that describe the electron gas dynamics driven by an external electromagnetic wave excitation. Our numerical approach is based on the Finite-Difference Time-Domain (FDTD method for solving the Maxwell’s equations and an explicit central finite difference method for solving the hydrodynamic electron fluid equations containing both electron density and current equations. Numerical results show good agreement with the experiment of studying the second-harmonic generation (SHG from metallic split-ring resonator (SRR.

  1. Capacity Analysis for Parallel Runway through Agent-Based Simulation

    Directory of Open Access Journals (Sweden)

    Yang Peng

    2013-01-01

    Full Text Available Parallel runway is the mainstream structure of China hub airport, runway is often the bottleneck of an airport, and the evaluation of its capacity is of great importance to airport management. This study outlines a model, multiagent architecture, implementation approach, and software prototype of a simulation system for evaluating runway capacity. Agent Unified Modeling Language (AUML is applied to illustrate the inbound and departing procedure of planes and design the agent-based model. The model is evaluated experimentally, and the quality is studied in comparison with models, created by SIMMOD and Arena. The results seem to be highly efficient, so the method can be applied to parallel runway capacity evaluation and the model propose favorable flexibility and extensibility.

  2. Flexible carbon nanotube sensors for nerve agent simulants

    Science.gov (United States)

    Cattanach, Kyle; Kulkarni, Rashmi D.; Kozlov, Mikhail; Manohar, Sanjeev K.

    2006-08-01

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 µm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 µm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems.

  3. Multi-Agent Competition Simulation of Integrated Transportation System

    Directory of Open Access Journals (Sweden)

    Jiashun Zhang

    2013-01-01

    Full Text Available Transportation networks have been developed during the recent decades with the rapid growth of economy. At the same time, the conflicts between different transportation modes were getting more and more intense. To describe the competition relationship in integrated transportation system, a multi-agent competition model was presented. It is important to provide decision support for regulators to lead more reasonable distribution of resources for planning and operating the integrated transportation network. Thus, a simulation program was developed to implement the proposed model and provide computer-aid decision support. Finally, several experiments were conducted to illustrate the effectiveness of this technique.

  4. Agent-based simulation of electricity markets. A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Sensfuss, F.; Ragwitz, M. [Fraunhofer-Institut fuer Systemtechnik und Innovationsforschung (ISI), Karlsruhe (Germany); Genoese, M.; Moest, D. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Industriebetriebslehre und Industrielle Produktion

    2007-07-01

    Liberalisation, climate policy and promotion of renewable energy are challenges to players of the electricity sector in many countries. Policy makers have to con-sider issues like market power, bounded rationality of players and the appear-ance of fluctuating energy sources in order to provide adequate legislation. Fur-thermore the interactions between markets and environmental policy instru-ments become an issue of increasing importance. A promising approach for the scientific analysis of these developments is the field of agent-based simulation. The goal of this article is to provide an overview of the current work applying this methodology to the analysis of electricity markets. (orig.)

  5. Simulation of Cognitive Pedestrian Agents Crowds in Crisis Situations

    Directory of Open Access Journals (Sweden)

    Margaret Lyell

    2006-06-01

    Full Text Available In crisis situations in an urban environment, first responder teams often must deal with crowds of people. Consider the case of a building fire in a dense city environment. People may be injured; walkways may be blocked, with fire equipment attempting to reach the scene. Crowd behavior can become an issue when trying to reach the injured, ensure safety and restore conditions to normal. The motivations of pedestrians that form the crowd can vary. Some are there because they are curious about the crisis situation. Others, attending to their individual concerns, may have found themselves in the 'wrong' location. They may be trying to leave the area, but the density of people as well as the spatial layout of the walkways may be impeding their progress. Other individuals, unaware of the fire, may be attempting to reach their intended destinations that happen to be near the crisis area, thus adding to crowd congestion. With a model of crowd behavior, effective strategies for resource usage in managing crowd behavior can be developed. Our approach to this problem is that of agent-based modeling and simulation. We develop a cognitive pedestrian agent model. Utilizing this model, we simulate crowd behavior in a 'city fire' scenario. Characteristics of crowd behavior with different pedestrian personality mixes and a strategy for crowd management are investigated

  6. Simulating Interactive Learning Scenarios with Intelligent Pedagogical Agents in a Virtual World through BDI-Based Agents

    Directory of Open Access Journals (Sweden)

    Mohamed Soliman

    2013-04-01

    Full Text Available Intelligent Pedagogical Agents (IPAs are designed for pedagogical purposes to support learning in 3D virtual learning environments. Several benefits of IPAs have been found adding to support learning effectiveness. Pedagogical agents can be thought of as a central point of interaction between the learner and the learning environment. And hence, the intelligent behavior and functional richness of pedagogical agents have the potential to reward back into increased engagement and learning effectiveness. However, the realization of those agents remains to be a challenge based on intelligent agents in virtual worlds. This paper reports the challenging reasons and most importantly an approach for simplification. A simulation based on BDI agents is introduced opening the road for several extensions and experimentation before implementation of IPAs in a virtual world can take place. The simulation provides a proof-of concept based on three intelligent agents to represent an IPA, a learner, and learning object implemented in JACK and Jadex intelligent agent platforms. To that end, the paper exhibits the difficulties, resolutions, and decisions made when designing and implementing the learning scenario in both domains of the virtual world and the agent-based simulation while comparing the two agent platforms.

  7. FDTD based transition time dependent crosstalk analysis for coupled RLC interconnects

    International Nuclear Information System (INIS)

    The performance of high density chips operating in the GHz range is mostly affected by on-chip interconnects. The interconnect delay depends on many factors, a few of them are inputs toggling patterns, line and coupling parasitics, input rise/fall time and source/load characteristics. The transition time of the input is of prime importance in high speed circuits. This paper addresses the FDTD based analysis of transition time effects on functional and dynamic crosstalk. The analysis is carried out for equal and unequal transition times of coupled inputs. The analysis of the effects of unequal rise time is equally important because practically, it is quite common to have mismatching in the rise time of the signals transmitting through different length wires. To demonstrate the effects, two distributed RLC lines coupled inductively and capacitively are taken into consideration. The FDTD technique is used because it gives accurate results and carries time domain analysis of coupled lines. The number of lumps in SPICE simulations is considered the same as those of spatial segments. To validate the FDTD computed results, SPICE simulations are run and results are compared. A good agreement of the computed results has been observed with respect to SPICE simulated results. An average error of less than 3.2% is observed in the computation of the performance parameters using the proposed method. (semiconductor integrated circuits)

  8. Flexible carbon nanotube sensors for nerve agent simulants

    International Nuclear Information System (INIS)

    Chemiresistor-based vapour sensors made from network films of single-walled carbon nanotube (SWNT) bundles on flexible plastic substrates (polyethylene terephthalate, PET) can be used to detect chemical warfare agent simulants for the nerve agents Sarin (diisopropyl methylphosphonate, DIMP) and Soman (dimethyl methylphosphonate, DMMP). Large, reproducible resistance changes (75-150%), are observed upon exposure to DIMP or DMMP vapours, and concentrations as low as 25 ppm can be detected. Robust sensor response to simulant vapours is observed even in the presence of large equilibrium concentrations of interferent vapours commonly found in battle-space environments, such as hexane, xylene and water (10 000 ppm each), suggesting that both DIMP and DMMP vapours are capable of selectively displacing other vapours from the walls of the SWNTs. Response to these interferent vapours can be effectively filtered out by using a 2 μm thick barrier film of the chemoselective polymer polyisobutylene (PIB) on the SWNT surface. These network films are composed of a 1-2 μm thick non-woven mesh of SWNT bundles (15-30 nm diameter), whose sensor response is qualitatively and quantitatively different from previous studies on individual SWNTs, or a network of individual SWNTs, suggesting that vapour sorption at interbundle sites could be playing an important role. This study also shows that the line patterning method used in device fabrication to obtain any desired pattern of films of SWNTs on flexible substrates can be used to rapidly screen simulants at high concentrations before developing more complicated sensor systems

  9. Agent-based modeling to simulate the dengue spread

    Science.gov (United States)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

  10. Agent-based simulation of alternative classroom evacuation scenarios

    Directory of Open Access Journals (Sweden)

    Runjiao Liu

    2016-03-01

    Full Text Available Due to the growing number of emergency accidents occurring around students, evacuation issues have become significantly important for both school officials and architects. Simply following construction codes cannot ensure that a building׳s layout is suitable for evacuation behaviors; therefore, to discover the suitable planning schemes, we have introduced an agent-based simulation model via Netlogo to investigate the interrelationships between evacuation efficiency and classroom layouts. Before conducting modeling experiments, both the simulation structure and the sensitivity to its parameter settings are examined by validation research and sensitivity analysis. Furthermore, to demonstrate the importance of conducting fire drills with students, two different types of behavior rules are designed to reflect the distinctive characteristics of students evacuating without instructions and students evacuating in good order. The general comparison results show us that the classroom layout with two exits shortens students׳ evacuation time, and the premeditated behavior rules, meaning that students who follow preset instructions to arrange their activities, not only escape faster but also have some advantages in ensuring their safety during the evacuation process. Moreover, at the end of this paper, several methods of improving this simulation model are proposed for more complex research in the future.

  11. Nanoporous Anodic Alumina 3D FDTD Modelling for a Broad Range of Inter-pore Distances.

    Science.gov (United States)

    Bertó-Roselló, Francesc; Xifré-Pérez, Elisabet; Ferré-Borrull, Josep; Pallarès, Josep; Marsal, Lluis F

    2016-12-01

    The capability of the finite difference time domain (FDTD) method for the numerical modelling of the optical properties of nanoporous anodic alumina (NAA) in a broad range of inter-pore distances is evaluated. FDTD permits taking into account in the same numerical framework all the structural features of NAA, such as the texturization of the interfaces or the incorporation of electrolyte anions in the aluminium oxide host. The evaluation is carried out by comparing reflectance measurements from two samples with two very different inter-pore distances with the simulation results. Results show that considering the texturization is crucial to obtain good agreement with the measurements. On the other hand, including the anionic layer in the model leads to a second-order contribution to the reflectance spectrum. PMID:27518230

  12. Optimization of band-notched UWB antenna using micro-genetic algorithm combined with FDTD

    Institute of Scientific and Technical Information of China (English)

    YANG; Xue-xia; SHENG; Jie

    2009-01-01

    The micro-genetic algorithm(MGA)optimization combined with the finite-difference time-domain(FDTD)method is applied to design a band-notched ultra wide-band(UWB)antenna. A U-type slot on a stepped U-type UWB monopole is used to obtain the band-notched characteristic for 5 GHz wireless local area network(WLAN)band. The measured results show that voltage standing wave ration(VSWR)less than 2 covers 3.1-10.6 GHz operating band and VSWR more than 2 is within 5.150-5.825 GHz notched one with the highest value of 5.6. Agreement among the calculated, HFSS simulated and measured results validates the effectiveness of this MGA-FDTD method, which is efficient for UWB antennas design.

  13. Crisis response simulation combining discrete-event and agent-based modeling

    NARCIS (Netherlands)

    Gonzalez, R.A.

    2009-01-01

    This paper presents a crisis response simulation model architecture combining a discrete-event simulation (DES) environment for a crisis scenario with an agent-based model of the response organization. In multi-agent systems (MAS) as a computational organization, agents are modeled and implemented s

  14. Modeling, Simulation, and Characterization of Distributed Multi-agent Systems

    Directory of Open Access Journals (Sweden)

    Reed F. Young

    2012-04-01

    Full Text Available A strategy is described that utilizes a novel application of a potential-force function that includes the tuning of coefficients to control mobile robots orchestrated as a distributed multiagent system. Control system parameters are manipulated methodically via simulation and hardware experimentation to gain a better understanding of their impact upon mission performance of the multi-agent system as applied to a predetermined task of area exploration and mapping. Also included are descriptions of experiment infrastructure components that afford convenient solutions to research challenges. These consist of a surrogate localization (position and orientation function utilizing a novel MATLAB executable (MEX function and a user datagram protocol (UDP-based communications protocol that facilitates communication among network-based control computers.

  15. Using Agent Based Modeling (ABM) to Develop Cultural Interaction Simulations

    Science.gov (United States)

    Drucker, Nick; Jones, Phillip N.

    2012-01-01

    Today, most cultural training is based on or built around "cultural engagements" or discrete interactions between the individual learner and one or more cultural "others". Often, success in the engagement is the end or the objective. In reality, these interactions usually involve secondary and tertiary effects with potentially wide ranging consequences. The concern is that learning culture within a strict engagement context might lead to "checklist" cultural thinking that will not empower learners to understand the full consequence of their actions. We propose the use of agent based modeling (ABM) to collect, store, and, simulating the effects of social networks, promulgate engagement effects over time, distance, and consequence. The ABM development allows for rapid modification to re-create any number of population types, extending the applicability of the model to any requirement for social modeling.

  16. Simulation of Service Supply Chain Formation Based on Mobile Agent

    Institute of Scientific and Technical Information of China (English)

    YANG Zhe; ZHANG Da-lu; XU Jian

    2005-01-01

    In E-Commerce, consumers and service suppliers can find the services through the searching of Mobile Agents (MA).The suppliers disassemble the service requests of consumers into the sub-requests. Then suppliers respond the subrequests cooperatively. Thus the Service Supply Chain(SSC) can be formed. But the existing bottom-up and upbottom supply chain formation fashions cannot be adapted to the SSC in distributed environment of E-Commerce. Task Dependency Network is exploited to illustrate the service relationship among consumers and suppliers. The formation of SSC with some simulations is elaborated. Then the influence on the formation of SSC caused by the type of service suppliers, the quantities of MA and its variety in number is elucidated.

  17. Agent-based modeling: Methods and techniques for simulating human systems

    OpenAIRE

    Bonabeau, Eric

    2002-01-01

    Agent-based modeling is a powerful simulation modeling technique that has seen a number of applications in the last few years, including applications to real-world business problems. After the basic principles of agent-based simulation are briefly introduced, its four areas of application are discussed by using real-world applications: flow simulation, organizational simulation, market simulation, and diffusion simulation. For each category, one or several business applications are described ...

  18. FDTD Modeling of Nano- and Bio-Photonic Imaging

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Tuchin, Valery; Pond, James

    2010-01-01

    address newly emerging problems and not so much on its mathematical formulation. We will first discuss the application of a traditional formulation of the FDTD approach to the modeling of sub-wavelength photonics structures. Next, a modified total/scattered field FDTD approach will be applied to the...... modeling of biophotonics applications including Optical Phase Contrast Microscope (OPCM) imaging of cells containing gold nanoparticles (NPs) as well as its potential application as a modality for in vivo flow cytometry configurations....

  19. Patient-centered appointment scheduling using agent-based simulation.

    Science.gov (United States)

    Turkcan, Ayten; Toscos, Tammy; Doebbeling, Brad N

    2014-01-01

    Enhanced access and continuity are key components of patient-centered care. Existing studies show that several interventions such as providing same day appointments, walk-in services, after-hours care, and group appointments, have been used to redesign the healthcare systems for improved access to primary care. However, an intervention focusing on a single component of care delivery (i.e. improving access to acute care) might have a negative impact other components of the system (i.e. reduced continuity of care for chronic patients). Therefore, primary care clinics should consider implementing multiple interventions tailored for their patient population needs. We collected rapid ethnography and observations to better understand clinic workflow and key constraints. We then developed an agent-based simulation model that includes all access modalities (appointments, walk-ins, and after-hours access), incorporate resources and key constraints and determine the best appointment scheduling method that improves access and continuity of care. This paper demonstrates the value of simulation models to test a variety of alternative strategies to improve access to care through scheduling. PMID:25954423

  20. Agent-based simulation of military operations other than war small unit combat

    OpenAIRE

    Woodaman, Ronald F. A.

    2000-01-01

    A significant challenge to the Armed Forces today is the development of tactics, techniques, procedures, and equipment that will enable success in the small-scale combats that characterize Military Operations Other Than War (MOOTW). This thesis develops an agent-based simulation methodology for modeling MOOTW combat scenarios. The methodology combines agent-based modeling with discrete event simulation in a software package called AgentKit. AgentKit is used to model a riot control problem for...

  1. AGENT-BASED CROWD SIMULATION CONSIDERING EMOTION CONTAGION FOR EMERGENCY EVACUATION PROBLEM

    Directory of Open Access Journals (Sweden)

    H. Faroqi

    2015-12-01

    Full Text Available During emergencies, emotions greatly affect human behaviour. For more realistic multi-agent systems in simulations of emergency evacuations, it is important to incorporate emotions and their effects on the agents. In few words, emotional contagion is a process in which a person or group influences the emotions or behavior of another person or group through the conscious or unconscious induction of emotion states and behavioral attitudes. In this study, we simulate an emergency situation in an open square area with three exits considering Adults and Children agents with different behavior. Also, Security agents are considered in order to guide Adults and Children for finding the exits and be calm. Six levels of emotion levels are considered for each agent in different scenarios and situations. The agent-based simulated model initialize with the random scattering of agent populations and then when an alarm occurs, each agent react to the situation based on its and neighbors current circumstances. The main goal of each agent is firstly to find the exit, and then help other agents to find their ways. Numbers of exited agents along with their emotion levels and damaged agents are compared in different scenarios with different initialization in order to evaluate the achieved results of the simulated model. NetLogo 5.2 is used as the multi-agent simulation framework with R language as the developing language.

  2. Agent-Based Crowd Simulation Considering Emotion Contagion for Emergency Evacuation Problem

    Science.gov (United States)

    Faroqi, H.; Mesgari, M.-S.

    2015-12-01

    During emergencies, emotions greatly affect human behaviour. For more realistic multi-agent systems in simulations of emergency evacuations, it is important to incorporate emotions and their effects on the agents. In few words, emotional contagion is a process in which a person or group influences the emotions or behavior of another person or group through the conscious or unconscious induction of emotion states and behavioral attitudes. In this study, we simulate an emergency situation in an open square area with three exits considering Adults and Children agents with different behavior. Also, Security agents are considered in order to guide Adults and Children for finding the exits and be calm. Six levels of emotion levels are considered for each agent in different scenarios and situations. The agent-based simulated model initialize with the random scattering of agent populations and then when an alarm occurs, each agent react to the situation based on its and neighbors current circumstances. The main goal of each agent is firstly to find the exit, and then help other agents to find their ways. Numbers of exited agents along with their emotion levels and damaged agents are compared in different scenarios with different initialization in order to evaluate the achieved results of the simulated model. NetLogo 5.2 is used as the multi-agent simulation framework with R language as the developing language.

  3. Construct validity of agent-based simulation of normative behaviour

    OpenAIRE

    Xenitidou, M; Elsenbroich, C

    2011-01-01

    In this paper we assess the construct validity and theoretical emdeddedness of agent-based models of normative behaviour drawing on experimental social psychology. We contend that social psychology and agent-based modelling share the focus of ‘observing’ the processes and outcomes of the interaction of individual agents. The paper focuses on two from a taxonomy of agent-based models of normative behaviour. This enables the identification of the assumptions the models are built on and in turn,...

  4. A Systematic Review of Agent-Based Modelling and Simulation Applications in the Higher Education Domain

    Science.gov (United States)

    Gu, X.; Blackmore, K. L.

    2015-01-01

    This paper presents the results of a systematic review of agent-based modelling and simulation (ABMS) applications in the higher education (HE) domain. Agent-based modelling is a "bottom-up" modelling paradigm in which system-level behaviour (macro) is modelled through the behaviour of individual local-level agent interactions (micro).…

  5. Serious games experiment toward agent-based simulation

    Science.gov (United States)

    Wein, Anne; Labiosa, William

    2013-01-01

    We evaluate the potential for serious games to be used as a scientifically based decision-support product that supports the United States Geological Survey’s (USGS) mission--to provide integrated, unbiased scientific information that can make a substantial contribution to societal well-being for a wide variety of complex environmental challenges. Serious or pedagogical games are an engaging way to educate decisionmakers and stakeholders about environmental challenges that are usefully informed by natural and social scientific information and knowledge and can be designed to promote interactive learning and exploration in the face of large uncertainties, divergent values, and complex situations. We developed two serious games that use challenging environmental-planning issues to demonstrate and investigate the potential contributions of serious games to inform regional-planning decisions. Delta Skelta is a game emulating long-term integrated environmental planning in the Sacramento-San Joaquin Delta, California, that incorporates natural hazards (flooding and earthquakes) and consequences for California water supplies amidst conflicting water interests. Age of Ecology is a game that simulates interactions between economic and ecologic processes, as well as natural hazards while implementing agent-based modeling. The content of these games spans the USGS science mission areas related to water, ecosystems, natural hazards, land use, and climate change. We describe the games, reflect on design and informational aspects, and comment on their potential usefulness. During the process of developing these games, we identified various design trade-offs involving factual information, strategic thinking, game-winning criteria, elements of fun, number and type of players, time horizon, and uncertainty. We evaluate the two games in terms of accomplishments and limitations. Overall, we demonstrated the potential for these games to usefully represent scientific information

  6. Hierarchical Distributed Control Design for Multi-agent Systems Using Approximate Simulation

    Institute of Scientific and Technical Information of China (English)

    TANG Yu-Tao; HONG Yi-Guang

    2013-01-01

    In this paper,we consider a hierarchical control design for multi-agent systems based on approximate simulation.To reduce complexity,we first construct a simple abstract system to guide the agents,then we discuss the simulation relations between the abstract system and multiple agents.With the help of this abstract system,distributed hierarchical control is proposed to complete a coordination task.By virtue of a common Lyapunov function,we analyze the collective behaviors with switching multi-agent topology in light of simulation functions.

  7. Study of High Robust Three Dimensional Finite Difference Time Domain (FDTD) Modeling of Ground Penetrating Radar for a Heterogeneous Environment

    Science.gov (United States)

    Eyuboglu, S.; Daniels, J. J.; Lee, R.; Yeh, J. T.

    2006-12-01

    Ground Penetrating Radar (GPR) is a non-invasive tool commonly used to characterize the physical properties of the subsurface. The translation of the physical measurements of geologic and hydrogeologic conditions is the culmination of many geophysical investigations. When numerical modeling is applied parallel to GPR data, it allows understanding of the effects of complex electromagnetic phenomena by defining and solving problems, as well as predicting the performance of radar in a complex heterogeneous environment. Finite difference time domain (FDTD) has been widely used for numerical modeling of GPR, but most of the previous algorithms are limited in their ability to model the electrical conductivity and permittivity. In this research, a highly efficient robust algorithm was developed to enhance the effectiveness of the FDTD forward modeling in surroundings characterized by an arbitrary distribution of all electrical properties in three dimensional space. In the first part of this research, two different FDTD codes which include different absorbing boundary conditions, Enquist and Majda absorbing boundary condition (ABC) and perfectly matched layer (PML), were used and compared. In the second part, the modeling algorithm was developed for a heterogeneous half-space medium to facilitate statistical modeling of complex distributions of electrical properties in the subsurface. The results produced by the simulation compared with real GPR results reveal high accuracy using the robust algorithm to optimize three dimensional FDTD forward modeling of GPR responses in heterogeneous surroundings.

  8. Macroeconomic Fluctuations and Propagation Mechanisms: An Agent-Based Simulation Model

    OpenAIRE

    Sella Lisa

    2009-01-01

    This paper proposes an agent-based simulation model exploring aggregate business fluctuations in an artificial market economy. It is inspired by the C++ agent-based simulation model in Howitt (2006), and proposes a modified NetLogo model, which provides new procedures and parameters aiming at analyzing the endogenous dynamics of market adjustment processes

  9. Simulated annealing algorithm for the optimal translation sequence of the jth agent in rough communication

    Institute of Scientific and Technical Information of China (English)

    Wang Hongkai; Guan Yanyong; Xue Peijun

    2008-01-01

    In rough communication, because each agent has a different language and cannot provide precise communication to each other, the concept translated among multi-agents will loss some information and this results in a less or rougher concept. With different translation sequences, the problem of information loss is varied. To get the translation sequence, in which the jth agent taking part in rough communication gets maximum information, a simulated annealing algorithm is used. Analysis and simulation of this algorithm demonstrate its effectiveness.

  10. A Multi-Agent System Using JADE for Simulation of Supply Chains

    Institute of Scientific and Technical Information of China (English)

    AHN Hyungjun; PARK Sungjoo

    2004-01-01

    This paper proposes a prototype system for modeling and simulation of supply chains using a widely accepted agent platform Java agent development platform (JADE). A simple but practical coordination mechanism agent-based dynamic information network for supply chains (ADINS) is employed for the illustration of the suggested system and a simulation experiment is performed using a supply chain model of a Korean LCD manufacturing company. The result shows that the suggested mechanism is successful in reducing bullwhip effects and increasing service rates.

  11. Object-Oriented Design for FDTD Visual Scientific Computing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A scheme for general purposed FDTD visual scientific computing software is introduced in this paper using object-oriented design (OOD) method. By abstracting the parameters of FDTD grids to an individual class and separating from the iteration procedure, the visual software can be adapted to more comprehensive computing problems. Real-time gray degree graphic and wave curve of the results can be achieved using DirectX technique. The special difference equation and data structure in dispersive medium are considered, and the peculiarity of parameters in perfectly matched layer are also discussed.``

  12. Applying FDTD to the Coverage Prediction of WiMAX Femtocells

    Directory of Open Access Journals (Sweden)

    Alvaro Valcarce

    2009-01-01

    Full Text Available Femtocells, or home base stations, are a potential future solution for operators to increase indoor coverage and reduce network cost. In a real WiMAX femtocell deployment in residential areas covered by WiMAX macrocells, interference is very likely to occur both in the streets and certain indoor regions. Propagation models that take into account both the outdoor and indoor channel characteristics are thus necessary for the purpose of WiMAX network planning in the presence of femtocells. In this paper, the finite-difference time-domain (FDTD method is adapted for the computation of radiowave propagation predictions at WiMAX frequencies. This model is particularly suitable for the study of hybrid indoor/outdoor scenarios and thus well adapted for the case of WiMAX femtocells in residential environments. Two optimization methods are proposed for the reduction of the FDTD simulation time: the reduction of the simulation frequency for problem simplification and a parallel graphics processing units (GPUs implementation. The calibration of the model is then thoroughly described. First, the calibration of the absorbing boundary condition, necessary for proper coverage predictions, is presented. Then a calibration of the material parameters that minimizes the error function between simulation and real measurements is proposed. Finally, some mobile WiMAX system-level simulations that make use of the presented propagation model are presented to illustrate the applicability of the model for the study of femto- to macrointerference.

  13. Crowd simulation influenced by agent's socio-psychological state

    CERN Document Server

    Cherif, F

    2010-01-01

    The aim our work is to create virtual humans as intelligent entities, which includes approximate the maximum as possible the virtual agent animation to the natural human behavior. In order to accomplish this task, our agent must be capable to interact with the environment, interacting with objects and other agents. The virtual agent needs to act as real person, so he should be capable to extract semantic information from the geometric model of the world where he is inserted, based on his own perception, and he realizes his own decision. The movement of the individuals is representing by the combination of two approaches of movement which are, the social force model and the based-rule model. These movements are influenced by a set of socio-psychological rules to give a more realistic result.

  14. A practical situation based agent architecture for social simulations

    OpenAIRE

    Alt, Jonathan K.; Baez, Francisco; Darken, Christian J.

    2011-01-01

    The concept of situation is central to the decision making processes of both human and software agents. The recognition of situation facilitates decision processes that ultimately result in action selection. Cognitive agent architectures that incorporate the concept of situation provide the opportunity for more sophisticated representation of human behavior and for more sophisticated decision support applications. This paper provides an overview of a general cognitive architecture for use ...

  15. An Agent-Based Simulation of In-Store Customer Experiences

    OpenAIRE

    Siebers, Peer-Olaf; Aickelin, Uwe; Celia, Helen; Clegg, Chris

    2008-01-01

    Agent-based modelling and simulation offers a new and exciting way of understanding the world of work. In this paper we describe the development of an agent-based simulation model, designed to help to understand the relationship between human resource management practices and retail productivity. We report on the current development of our simulation model which includes new features concerning the evolution of customers over time. To test some of these features we have conducted a series of ...

  16. Multi-agent Based Hierarchy Simulation Models of Carrier-based Aircraft Catapult Launch

    Institute of Scientific and Technical Information of China (English)

    Wang Weijun; Qu Xiangju; Guo Linliang

    2008-01-01

    With the aid of multi-agent based modeling approach to complex systems,the hierarchy simulation models of carrier-based aircraft catapult launch are developed.Ocean,carrier,aircraft,and atmosphere are treated as aggregation agents,the detailed components like catapult,landing gears,and disturbances are considered as meta-agents,which belong to their aggregation agent.Thus,the model with two layers is formed i.e.the aggregation agent layer and the meta-agent layer.The information communication among all agents is described.The meta-agents within one aggregation agent communicate with each other directly by information sharing,but the meta-agents,which belong to different aggregation agents exchange their information through the aggregation layer fast,and then perceive it from the sharing environment,that is the aggregation agent.Thus,not only the hierarchy model is built,but also the environment perceived by each agent is specified.Meanwhile,the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system (MAS) is resolved.Each agent involved in carrier-based aircraft catapult launch is depicted,with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier,aircraft,and landing gears.The models of reactive agents among them are derived based on tensors,and the perceived messages and inner frameworks of each agent are characterized.Finally,some results of a simulation instance are given.The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely.The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system.This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent,and it is convenient to expand,maintain,and reuse

  17. FDTD analysis of a noninvasive hyperthermia system for brain tumors

    Directory of Open Access Journals (Sweden)

    Yacoob Sulafa M

    2012-08-01

    Full Text Available Abstract Background Hyperthermia is considered one of the new therapeutic modalities for cancer treatment and is based on the difference in thermal sensitivity between healthy tissues and tumors. During hyperthermia treatment, the temperature of the tumor is raised to 40–45°C for a definite period resulting in the destruction of cancer cells. This paper investigates design, modeling and simulation of a new non-invasive hyperthermia applicator system capable of effectively heating deep seated as well as superficial brain tumors using inexpensive, simple, and easy to fabricate components without harming surrounding healthy brain tissues. Methods The proposed hyperthermia applicator system is composed of an air filled partial half ellipsoidal chamber, a patch antenna, and a head model with an embedded tumor at an arbitrary location. The irradiating antenna is placed at one of the foci of the hyperthermia chamber while the center of the brain tumor is placed at the other focus. The finite difference time domain (FDTD method is used to compute both the SAR patterns and the temperature distribution in three different head models due to two different patch antennas at a frequency of 915 MHz. Results The obtained results suggest that by using the proposed noninvasive hyperthermia system it is feasible to achieve sufficient and focused energy deposition and temperature rise to therapeutic values in deep seated as well as superficial brain tumors without harming surrounding healthy tissue. Conclusions The proposed noninvasive hyperthermia system proved suitable for raising the temperature in tumors embedded in the brain to therapeutic values by carefully selecting the systems components. The operator of the system only needs to place the center of the brain tumor at a pre-specified location and excite the antenna at a single frequency of 915 MHz. Our study may provide a basis for a clinical applicator prototype capable of heating brain tumors.

  18. Agent-based simulation of a Marine Infantry Squad in an urban environment

    OpenAIRE

    Aragon, Arthur R.

    2001-01-01

    This thesis research focused on the design, development and implementation of an agent based simulation of a Marine infantry squad in an urban environment. The goal was to design an autonomous-agent framework that could model a combatantαs decision cycle. A squad entity comprised of these agents was created to explore the idea of team dynamics and the balance between meeting individual goals and team goals. The agents were placed in a two-dimensional, discrete-state, simulation world with a ...

  19. FDTD-based computed terahertz wave propagation in multilayer medium structures

    Science.gov (United States)

    Tu, Wan-li; Zhong, Shun-cong; Yao, Hai-zi; Shen, Yao-chun

    2013-08-01

    The terahertz region of the electromagnetic spectrum spans the frequency range of 0.1THz~10THz, which means it sandwiches between the mid-infrared (IR) and the millimeter/ microwave. With the development and commercialization of terahertz pulsed spectroscopy (TPS) and terahertz pulsed imaging (TPI) systems, terahertz technologies have been widely used in the sensing and imaging fields. It allows high quality cross-sectional images from within scattering media to be obtained nondestructively. Characterizing the interaction of terahertz radiation with multilayer medium structures is critical for the development of nondestructive testing technology. Currently, there was much experimental investigation of using TPI for the characterization of terahertz radiation in materials (e.g., pharmaceutical tablet coatings), but there were few theoretical researches on propagation of terahertz radiation in multilayer medium structures. Finite Difference Time Domain (FDTD) algorithm is a proven method for electromagnetic scattering theory, which analyzes continuous electromagnetic problems by employing finite difference and obtains electromagnetic field value at the sampling point to approach the actual continuous solutions. In the present work, we investigated the propagation of terahertz radiation in multilayer medium structures based on FDTD method. The model of multilayer medium structures under the THz frequency plane wave incidence was established, and the reflected radiation properties were recorded and analyzed. The terahertz radiation used was broad-band in the frequency up to 2 THz. A batch of single layer coated pharmaceutical tablets, whose coating thickness in the range of 40~100μm, was computed by FDTD method. We found that the simulation results on pharmaceutical tablet coatings were in good agreement with the experimental results obtained using a commercial system (TPI imaga 2000, TeraView, Cambridge, UK) , demonstrating its usefulness in simulating and analyzing

  20. Simulation of the Rungis Wholesale Market: Lessons on the Calibration, Validation and Usage of a Cognitive Agent-Based Simulation

    OpenAIRE

    Caillou, Philippe; Curchod, Corentin; Baptista, Tiago

    2009-01-01

    International audience We present some methodological lessons and thoughts inferred from a research we are making on a simulation of the Rungis Wholesale Market (in France) using cognitive agents. The implication of using cognitive agents with an objective of realism at the individual level question some of the classical methodological assertions about simulations. Three such lessons are of particular interest: the calibration and validation focus on individuals rather than global values (...

  1. A Participatory Agent-Based Simulation for Indoor Evacuation Supported by Google Glass.

    Science.gov (United States)

    Sánchez, Jesús M; Carrera, Álvaro; Iglesias, Carlos Á; Serrano, Emilio

    2016-01-01

    Indoor evacuation systems are needed for rescue and safety management. One of the challenges is to provide users with personalized evacuation routes in real time. To this end, this project aims at exploring the possibilities of Google Glass technology for participatory multiagent indoor evacuation simulations. Participatory multiagent simulation combines scenario-guided agents and humans equipped with Google Glass that coexist in a shared virtual space and jointly perform simulations. The paper proposes an architecture for participatory multiagent simulation in order to combine devices (Google Glass and/or smartphones) with an agent-based social simulator and indoor tracking services. PMID:27563911

  2. Efficient Calculation of Near Fields in the FDTD Method

    DEFF Research Database (Denmark)

    Franek, Ondrej

    2011-01-01

    When calculating frequency-domain near fields by the FDTD method, almost 50 % reduction in memory and CPU operations can be achieved if only E-fields are stored during the main time-stepping loop and H-fields computed later. An improved method of obtaining the H-fields from Faraday's Law is...

  3. An agent based approach for simulating complex systems with spatial dynamicsapplication in the land use planning

    Directory of Open Access Journals (Sweden)

    Fatimazahra BARRAMOU

    2012-12-01

    Full Text Available In this research a new agent based approach for simulating complex systems with spatial dynamics is presented. We propose architecture based on coupling between two systems: multi-agent systems and geographic information systems. We also propose a generic model of agent-oriented simulation that we will apply to the field of land use planning. In fact, simulating the evolution of the urban system is a key to help decision makers to anticipate the needs of the city in terms of installing new equipment and opening new urbanization’ areas to install the new population.

  4. Techniques, Advantages and Problems of Agent Based Modeling for Traffic Simulation

    Directory of Open Access Journals (Sweden)

    Ali Bazghandi

    2012-01-01

    Full Text Available Agent-based modeling (ABM is a powerful simulation modeling technique in the last few years. ABM, as an approach to simulating the behavior of a complex system in which agents interact with each other and with their environment using simple local rules, is gaining popularity and widespread use in many areas. Successes of this approach in predicting traffic flow in metropolitan areas, the spread of infectious diseases, and the behavior of economic systems have generated further interest in this powerful technology. In this paper we focus on agent-based approach to traffic simulation, and investigate its benefits, difficulties and (microscopic-macroscopic techniques.

  5. Application potential of Agent Based Simulation and Discrete Event Simulation in Enterprise integration modelling concepts

    Directory of Open Access Journals (Sweden)

    Paul-Eric DOSSOU

    2013-07-01

    Full Text Available Normal 0 21 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} This paper aims to present the dilemma of simulation tool selection. Authors discuss the examples of methodologies of enterprises architectures (CIMOSA and GRAI where agent approach is used to solve planning and managing problems. Actually simulation is widely used and practically only one tool which can enable verification of complex systems. Many companies face the problem, which simulation tool is appropriate to use for verification. Selected tools based on ABS and DES are presented. Some tools combining DES and ABS approaches are described. Authors give some recommendation on selection process.

  6. Application potential of Agent Based Simulation and Discrete Event Simulation in Enterprise integration modelling concepts

    Directory of Open Access Journals (Sweden)

    Pawel PAWLEWSKI

    2012-07-01

    Full Text Available Normal 0 21 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} This paper aims to present the dilemma of simulation tool selection. Authors discuss the examples of methodologies of enterprises architectures (CIMOSA and GRAI where agent approach is used to solve planning and managing problems. Actually simulation is widely used and practically only one tool which can enable verification of complex systems. Many companies face the problem, which simulation tool is appropriate to use for verification. Selected tools based on ABS and DES are presented. Some tools combining DES and ABS approaches are described. Authors give some recommendation on selection process.

  7. The Usability of Agent-Based Simulation in Decision Support System of E-Commerce Architecture

    Directory of Open Access Journals (Sweden)

    ŠPERKA Roman

    2012-02-01

    Full Text Available Electronic commerce (e-commerce has the potential to improve the competitiveness of the enterprises. A decision support system, used in e-commerce, is a term used to describe any software engine that enhances the user’s ability to make decisions. The paper presents a new approach for decision support system modeling. This approach is applied by a modification and extension of existing decision support system architecture by multi-agent technology and agent-based simulation models. Multi-agent technology is one of the fastest growing fields of information and communication technology – new agent-based services, products, and applications are being developed almost every day. Agent-based simulation model is applied to coordinate, control, and simulate the architecture of decision support system, used in e-commerce. The proposed architecture improves the existing decision support systems and gains competitive advantage.

  8. An Introduction to Agent Based Modelling and Simulation of Social Processes

    OpenAIRE

    Ognjen Skunca; Armano Srbljinovic

    2003-01-01

    The paper provides an introduction to agent-based modelling and simulation of social processes. Reader is introduced to the worldview underlying agent-based models, some basic terminology, basic properties of agent-based models, as well as to what one can and what cannot expect from such models, particularly when they are applied to social-scientific investigation. Special attention is given to the issues of validation.

  9. Simulation of the dynamics of contrast agents in an ultrasonic field

    International Nuclear Information System (INIS)

    A one-dimensional computational model allowing the investigation of the oscillatory dynamics and translational displacement of free bubbles and contrast agents in ultrasonic fields of varying intensity has been developed. Numerical simulation of contrast agents with thick and thin shells has been conducted. The influence of the rheological properties of the shell on the dynamics of contrast agents has been investigated and their resonant frequency has been estimated

  10. Agent-Based Modeling and Genetic Algorithm Simulation for the Climate Game Problem

    OpenAIRE

    Zheng Wang; Jingling Zhang

    2012-01-01

    The cooperative game of global temperature lacks automaticity and emotional jamming. To solve this issue, an agent-based modelling method is developed based on Milinski’s noncooperative game experiments. In addition, genetic algorithm is used to improve the investment strategy of each agent. Simulations are carried out by designing different coding schemes, mutation schemes, and fitness functions. It is demonstrated that the method can achieve maximum benefits under the premise of the agent n...

  11. Agent-Based Simulation and Assessment of NAS Security and Safety Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The key innovation proposed here is the use of agent-based modeling and simulation to evaluate the safety of the National Airspace under crisis operations and...

  12. Agent-based Social Simulation tools: Brahms and NetLogo

    NARCIS (Netherlands)

    Sie, Rory

    2010-01-01

    Sie, R. L. L. (2010, 21 September). Agent-based Social Simulation tools: Brahms and NetLogo. Presentation at the Learning Networks Plenary, Heerlen, The Netherlands: Open University of the Netherlands.

  13. The individual agent makes a difference in segregation simulation

    OpenAIRE

    Koch, Andreas

    2014-01-01

    Urban social segregation modeling from the bottom up attempts at understanding the processes which take place when residents look for a new home. This micro-scale perspective thus requires implementing actual individual agents instead of socially unified communities with similar or identical behavior. Complementary, meso- and macro-scale determinants such as housing markets, estate agencies, urban planning institutions, and societal life-style preferences must be incorporated in order to comp...

  14. Heat Conduction Analysis in a Tissue Phantom Calculated by FDTD and HCE Method

    Science.gov (United States)

    Endoh, Nobuyuki; Tsuchiya, Takenobu; Saito, Yoshikazu; Ishizeki, Takahiro

    2005-03-01

    In order to study hyperthermia in tissue, it is important to predict accurately the heat distribution. This paper describes a preliminary study of the comparison between simulation and experiment for heat conduction in a simple tissue phantom. Since it is well known that the heat increase in tissue depends on the sound intensity and the absorption coefficient, the sound pressure distribution is calculated using a Finite Difference Time Domain (FDTD) method. The thermal diffusion profile in tissue generated by the energy of the sound pulse is also simulated using the Heat Conduction Equation (HCE) method. The calculation area is 100 × 40 [mm]. The simple tissue phantom is made of agar, water and graphite. The phantom whose attenuation coefficient is 1.1 dB/cm/MHz is placed in a temperature controlled water bath. This is kept at 37 degrees [C] while sound pulses of 1 MHz are emitted over 10 minutes. Temperatures at six points on the acoustic axis are measured in the phantom. The calculation and experiment results are compared to confirm the accuracy of the proposed method. As a result, the calculation results show the validity of the combined FDTD-HCE method for thermal conduction analysis.

  15. Heat Conduction Analysis in a Tissue Phantom Calculated by FDTD and HCE Method

    International Nuclear Information System (INIS)

    In order to study hyperthermia in tissue, it is important to predict accurately the heat distribution. This paper describes a preliminary study of the comparison between simulation and experiment for heat conduction in a simple tissue phantom. Since it is well known that the heat increase in tissue depends on the sound intensity and the absorption coefficient, the sound pressure distribution is calculated using a Finite Difference Time Domain (FDTD) method. The thermal diffusion profile in tissue generated by the energy of the sound pulse is also simulated using the Heat Conduction Equation (HCE) method. The calculation area is 100 x 40 [mm]. The simple tissue phantom is made of agar, water and graphite. The phantom whose attenuation coefficient is 1.1 dB/cm/MHz is placed in a temperature controlled water bath. This is kept at 37 deg. [C] while sound pulses of 1 MHz are emitted over 10 minutes. Temperatures at six points on the acoustic axis are measured in the phantom. The calculation and experiment results are compared to confirm the accuracy of the proposed method. As a result, the calculation results show the validity of the combined FDTD-HCE method for thermal conduction analysis

  16. Pricing and Timing Strategies for New Product Using Agent-Based Simulation of Behavioural Consumers

    OpenAIRE

    Keeheon Lee; Hoyeop Lee; Chang Ouk Kim

    2014-01-01

    In this study, we are interested in the problem of determining the pricing and timing strategies of a new product by developing an agent-based product diffusion simulation. In the proposed simulation model, agents imitate behavioural consumers, who are reference dependent and risk averse in the evaluation of new products and whose interactions create word-of-mouth regarding new products. Pricing and timing strategies involve the timing of a new product release, the timing of providing a disco...

  17. An information theory based behavioral model for agent-based crowd simulations

    OpenAIRE

    Turkay, Çağatay; Turkay, Cagatay; Koç, Emre; Koc, Emre; Balcısoy, Selim; Balcisoy, Selim

    2010-01-01

    Crowds must be simulated believable in terms of their appearance and behavior to improve a virtual environment’s realism. Due to the complex nature of human behavior, realistic behavior of agents in crowd simulations is still a challenging problem. In this paper, we propose a novel behavioral model which builds analytical maps to control agents’ behavior adaptively with agent-crowd interaction formulations. We introduce information theoretical concepts to construct analytical maps automatical...

  18. The Third Way of Agent-Based Social Simulation and a Computational Account of Emergence

    OpenAIRE

    Roy Wilson

    2010-01-01

    This paper interprets a particular agent-based social simulation (ABSS) in terms of the third way of understanding agent-based simulation proposed by Conte. It is proposed that the normalized compression distance (derived from estimates of Kolmogorov complexity) between the initial and final macrolevel states of the ABSS provides a quantitative measure of the degree to which the results obtained via the ABSS might be obtained via a closed-form expression. If the final macrolevel state of an A...

  19. Comparing Stochastic Differential Equations and Agent-Based Modelling and Simulation for Early-Stage Cancer

    OpenAIRE

    Figueredo, Grazziela P.; Peer-Olaf Siebers; Owen, Markus R.; Jenna Reps; Uwe Aickelin

    2014-01-01

    There is great potential to be explored regarding the use of agent-based modelling and simulation as an alternative paradigm to investigate early-stage cancer interactions with the immune system. It does not suffer from some limitations of ordinary differential equation models, such as the lack of stochasticity, representation of individual behaviours rather than aggregates and individual memory. In this paper we investigate the potential contribution of agent-based modelling and simulation w...

  20. Exploring the World of Agent-Based Simulations: Simple Models, Complex Analyses

    OpenAIRE

    Sanchez, Susan M.; Lucas, Thomas W.

    2002-01-01

    Proceedings of the 2002 Winter Simulation Conference E. Yücesan, C.-H. Chen, J. L. Snowdon, and J. M. Charnes, eds. Agent-based simulations are models where multiple entities sense and stochastically respond to conditions in their local environments, mimicking complex large-scale system behavior. We provide an overview of some important issues in the modeling and analysis of agent-based systems. Examples are drawn from a range of fields: biological modeling, sociologic...

  1. Multi-Agent-Based Simulation for Analysis of Transport Policy and Infrastructure Measures

    OpenAIRE

    Holmgren, Johan; Ramstedt, Linda; Davidsson, Paul; Persson, Jan A.

    2012-01-01

    In this paper we elaborate on the usage of multi-agent-based simulation (MABS) for quantitative impact assessment of transport policy and infrastructure measures. We provide a general discussion on how to use MABS for freight transport analysis, focusing on issues related to input data management, validation and verification, calibration, output data analysis, and generalization of results. The discussion is built around an agent-based transport chain simulation tool called TAPAS (Transportat...

  2. Agent-Based Modeling and Simulation of Child Maltreatment and Child Maltreatment Prevention

    OpenAIRE

    Xiaolin Hu; Nicholas Keller

    2015-01-01

    This paper presents an agent-based model that simulates the dynamics of child maltreatment and child maltreatment prevention. The developed model follows the principles of complex systems science and explicitly models a community and its families with multi-level factors across the social ecology. Each agent includes behavioral/cognitive modeling to account for the behavioral/cognitive process of child maltreatment. Simulation of child maltreatment prevention is also supported to evaluate the...

  3. 基于FDTD法等离子体光子晶体的禁带特性研究%FDTD Simulation of Band Structures of Electromagnetic Wave Propagation in One-dimensional Plasma Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    郭斌; 曾进启; 张焕德

    2011-01-01

    The band structures of electromagnetic waves propagation in one-dimensional plasma photonic crystal is studied based on finite-difference domain-time method. The reflection and transmission of the incident Gaussian pulse are plotted. And the effects of the thickness of plasma layer and the dielectric constant of background materials are simulated and discussed. Parameters dependence of the effects are given.%研究了垂直入射的电磁波在一维等离子体光子晶体中的传播特性,采用时域有限差分方法数值模拟的方法讨论了等离子体厚度和介质材料的介电常数对电磁波在等离子体光子晶体中传播反射和透射特性的影响,给出相应参数的模拟结果.

  4. Agent-based modeling of malaria vectors: the importance of spatial simulation

    OpenAIRE

    Bomblies, Arne

    2014-01-01

    Background The modeling of malaria vector mosquito populations yields great insight into drivers of malaria transmission at the village scale. Simulation of individual mosquitoes as “agents” in a distributed, dynamic model domain may be greatly beneficial for simulation of spatial relationships of vectors and hosts. Methods In this study, an agent-based model is used to simulate the life cycle and movement of individual malaria vector mosquitoes in a Niger Sahel village, with individual simul...

  5. Crowd simulation incorporating agent psychological models, roles and communication

    OpenAIRE

    Pelechano Gómez, Núria; O'Brien, Kevin; Silverman, Barry G.; Badler, Norman

    2005-01-01

    We describe a new architecture to integrate a psychological model into a crowd simulation system in order to obtain believable emergent behaviors. Our existing crowd simulation system (MACES) performs high level wayfinding to explore unknown environments and obtain a cognitive map for navigation purposes, in addition to dealing with low level motion within each room based on social forces. Communication and roles are added to achieve individualistic behaviors and a realistic way to spread inf...

  6. Action Selection Properties in a Software Simulated Agent

    OpenAIRE

    Garcia, Carlos Gershenson; Perez, Pedro Pablo Gonzalez; Martinez, Jose Negrete

    2002-01-01

    This article analyses the properties of the Internal Behaviour network, an action selection mechanism previously proposed by the authors, with the aid of a simulation developed for such ends. A brief review of the Internal Behaviour network is followed by the explanation of the implementation of the simulation. Then, experiments are presented and discussed analysing the properties of the action selection in the proposed model.

  7. A computational-intelligence-based optimization of agents' initial positions in land combat simulation

    Institute of Scientific and Technical Information of China (English)

    WU Chunguo; LIANG Yanchun; GE Hongwei; CAO Lijuan; LEE Heow Pueh

    2003-01-01

    The optimization of agents' initial properties enables agents to perform their assigned tasks more perfectly. This paper presents an optimizing method using the combination of radial basis function (RBF) neural network and genetic algorithm (GA). In the land combat simulation, the method can ensure that the agents optimized defeat the agents not optimized absolutely. Compared with the optimization based on support vector machines (SVM), the proposed method improves the efficiency more than twenty times, so it suits the cases where the speed as well as performance is required.

  8. Numerical analysis of second harmonic generation for THz-wave in a photonic crystal waveguide using a nonlinear FDTD algorithm

    Science.gov (United States)

    Saito, Kyosuke; Tanabe, Tadao; Oyama, Yutaka

    2016-04-01

    We have presented a numerical analysis to describe the behavior of a second harmonic generation (SHG) in THz regime by taking into account for both linear and nonlinear optical susceptibility. We employed a nonlinear finite-difference-time-domain (nonlinear FDTD) method to simulate SHG output characteristics in THz photonic crystal waveguide based on semi insulating gallium phosphide crystal. Unique phase matching conditions originated from photonic band dispersions with low group velocity are appeared, resulting in SHG output characteristics. This numerical study provides spectral information of SHG output in THz PC waveguide. THz PC waveguides is one of the active nonlinear optical devices in THz regime, and nonlinear FDTD method is a powerful tool to design photonic nonlinear THz devices.

  9. Agent-based Models in Synthetic Biology: Tools for Simulation and Prospects

    Directory of Open Access Journals (Sweden)

    E.V.Krishnamurthy

    2012-03-01

    Full Text Available We describe a multiset of agents based modeling and simulation paradigm for synthetic biology. The multiset of agents –based programming paradigm, can be interpreted as the outcome arising out of deterministic, nondeterministic or stochastic interaction among elements in a multiset object space, that includes the environment. These interactions are like chemical reactions and the evolution of the multiset can emulate the system biological functions. Since the reaction rules are inherently parallel, any number of actions can be performed cooperatively or competitively among the subsets of elements, so that the elements evolve toward equilibrium or emergent state. Practical realization of this paradigm for system biological simulation is achieved through the concept of transactional style programming with agents, as well as soft computing (neural- network principles. Also we briefly describe currently available tools for agent-based-modeling, simulation and animation.

  10. Modelling and simulation of complex systems: an approach based on multi-level agents

    CERN Document Server

    Fougères, Alain-Jérôme

    2012-01-01

    A complex system is made up of many components with many interactions. So the design of systems such as simulation systems, cooperative systems or assistance systems includes a very accurate modelling of interactional and communicational levels. The agent-based approach provides an adapted abstraction level for this problem. After having studied the organizational context and communicative capacities of agentbased systems, to simulate the reorganization of a flexible manufacturing, to regulate an urban transport system, and to simulate an epidemic detection system, our thoughts on the interactional level were inspired by human-machine interface models, especially those in "cognitive engineering". To provide a general framework for agent-based complex systems modelling, we then proposed a scale of four behaviours that agents may adopt in their complex systems (reactive, routine, cognitive, and collective). To complete the description of multi-level agent models, which is the focus of this paper, we illustrate ...

  11. Research on monocentric model of urbanization by agent-based simulation

    Science.gov (United States)

    Xue, Ling; Yang, Kaizhong

    2008-10-01

    Over the past years, GIS have been widely used for modeling urbanization from a variety of perspectives such as digital terrain representation and overlay analysis using cell-based data platform. Similarly, simulation of urban dynamics has been achieved with the use of Cellular Automata. In contrast to these approaches, agent-based simulation provides a much more powerful set of tools. This allows researchers to set up a counterpart for real environmental and urban systems in computer for experimentation and scenario analysis. This Paper basically reviews the research on the economic mechanism of urbanization and an agent-based monocentric model is setup for further understanding the urbanization process and mechanism in China. We build an endogenous growth model with dynamic interactions between spatial agglomeration and urban development by using agent-based simulation. It simulates the migration decisions of two main types of agents, namely rural and urban households between rural and urban area. The model contains multiple economic interactions that are crucial in understanding urbanization and industrial process in China. These adaptive agents can adjust their supply and demand according to the market situation by a learning algorithm. The simulation result shows this agent-based urban model is able to perform the regeneration and to produce likely-to-occur projections of reality.

  12. Agent-based simulations of emotion spreading in online social networks

    CERN Document Server

    Šuvakov, Milovan; Schweitzer, Frank; Tadić, Bosiljka

    2012-01-01

    Quantitative analysis of empirical data from online social networks reveals group dynamics in which emotions are involved (\\v{S}uvakov et al). Full understanding of the underlying mechanisms, however, remains a challenging task. Using agent-based computer simulations, in this paper we study dynamics of emotional communications in online social networks. The rules that guide how the agents interact are motivated, and the realistic network structure and some important parameters are inferred from the empirical dataset of \\texttt{MySpace} social network. Agent's emotional state is characterized by two variables representing psychological arousal---reactivity to stimuli, and valence---attractiveness or aversiveness, by which common emotions can be defined. Agent's action is triggered by increased arousal. High-resolution dynamics is implemented where each message carrying agent's emotion along the network link is identified and its effect on the recipient agent is considered as continuously aging in time. Our res...

  13. Advances in FDTD computational electrodynamics photonics and nanotechnology

    CERN Document Server

    Oskooi, Ardavan; Johnson, Steven G

    2013-01-01

    Advances in photonics and nanotechnology have the potential to revolutionize humanity s ability to communicate and compute. To pursue these advances, it is mandatory to understand and properly model interactions of light with materials such as silicon and gold at the nanoscale, i.e., the span of a few tens of atoms laid side by side. These interactions are governed by the fundamental Maxwell s equations of classical electrodynamics, supplemented by quantum electrodynamics. This book presents the current state-of-the-art in formulating and implementing computational models of these interactions. Maxwell s equations are solved using the finite-difference time-domain (FDTD) technique, pioneered by the senior editor, whose prior Artech books in this area are among the top ten most-cited in the history of engineering. You discover the most important advances in all areas of FDTD and PSTD computational modeling of electromagnetic wave interactions. This cutting-edge resource helps you understand the latest develo...

  14. Agent Behavior-Based Simulation Study on Mass Collaborative Product Development Process

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2015-01-01

    Full Text Available Mass collaborative product development (MCPD benefits people by high innovation products with lower cost and shorter lead time due to quick development of group innovation, Internet-based customization, and prototype manufacturing. Simulation is an effective way to study the evolution process and therefore to guarantee the success of MCPD. In this paper, an agent behavior-based simulation approach of MCPD is developed, which models the MCPD process as the interactive process of design agents and the environment objects based on Complex Adaptive System (CAS theory. Next, the structure model of design agent is proposed, and the modification and collaboration behaviors are described. Third, the agent behavior-based simulation flow of MCPD is designed. At last, simulation experiments are carried out based on an engineering case of mobile phone design. The experiment results show the following: (1 the community scale has significant influence on MCPD process; (2 the simulation process can explicitly represent the modification and collaboration behaviors of design agents; (3 the community evolution process can be observed and analyzed dynamically based on simulation data.

  15. FDTD Computation of Human Eye Exposure to Ultra-wideband Electromagnetic Pulses

    CERN Document Server

    Simicevic, Neven

    2007-01-01

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29, and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of $\\rm 0.1 \\: mm$ and an...

  16. FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses

    International Nuclear Information System (INIS)

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW

  17. Study of FDTD algorithm based on CUDA platform%基于CUDA平台的时域有限差分算法研究

    Institute of Scientific and Technical Information of China (English)

    沈琛; 王璐; 胡玉娟; 吴先良

    2012-01-01

    In this paper, in view of the deficiencies in traditional finite-difference time-domain (FDTD) algorithm, the FDTD parallel algorithm based on Compute Unified Device Architecture(CUDA) platform is studied and realized by taking the graphics processing unit(GPU) as the core and using theoretical analysis and numerical simulation. The CUDA is a fairly new technology to program inexpensive multi-threaded GPUs. The FDTD algorithm is well suited for parallel processing across spatial domain, thus it is a good candidate for the execution on a GPU. The design and optimization of FDTD algorithm for CUDA programming model are discussed. The results of numerical experiments demonstrate that the computation time of GPU based parallel FDTD algorithm decreases significantly. The GPU based acceleration has been a hot topic in the studies of electromagnetic field numerical computation.%文章针对传统时域有限差分(FDTD)算法的不足,以图形加速卡为核心,通过理论分析和数值模拟,研究并实现了基于CUDA平台的FDTD并行算法.CUDA是最新的可编程多线程的通用计算GPU模型,由于FDTD算法在空间上具有天然的并行性,因此非常适合在GPU上实现并行算.文章描述了在CUDA编程模型上的FDTD算法的设计以及优化过程,并通过数值仿真实验结果证明了基于GPU的并行FDTD算法可以大大减少计算时间,基于GPU加速已成为电磁场数值计算的研究热点之一.

  18. Multi-agent systems for simulating spatial decision behaviors and land-use dynamics

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaoping; LI Xia; Anthony Gar-On Yeh

    2006-01-01

    A new method to simulate urban land-use dynamics is proposed based on multi-agent systems (MAS). The model consists of a series of environmental layers and multi-agent layers, which can interact with each other. It attempts to explore the interactions between different players or agents,such as residents, property developers, and governments, and between these players and the environment. These interactions can give rise to urban macro-spatial patterns. This model is used to simulate the land-use dynamics of the Haizhu district of Guangzhou City in 1995-2004. Cellular automata (CA) were also used for the simulation of land use changes as a comparison. The study indicates that MAS has better performance for simulating complex cities than CA.

  19. Generic personality and emotion simulation for conversational agents

    OpenAIRE

    Egges, A.; Kshirsagar, S.; Magnenat-Thalmann, N.

    2008-01-01

    This paper describes a generic model for personality, mood and emotion simulation for conversational virtual humans. We present a generic model for updating the parameters related to emotional behaviour, as well as a linear implementation of the generic update mechanisms. We explore how existing theories for appraisal can be integrated into the framework. Then we describe a prototype system that uses the described models in combination with a dialogue system and a talking head with synchroniz...

  20. Agent-Based Modeling and Simulation of Network Infrastructure Cyber-Attacks and Cooperative Defense Mechanisms

    OpenAIRE

    Kotenko, Igor

    2010-01-01

    This paper considered the approach to investigation of distributed cooperative cyberdefence mechanisms against network attacks. The approach is based on the simulation of network cyber-attacks (Distributed Denial of Service, network worms, botnets, etc.) and cyber-protection mechanisms which combines discrete-event simulation, multi-agent approach and packet-level simulation of network protocols. The environment developed is written in C++ and OMNeT++. It allows imitating a wide spectrum of r...

  1. The Impact of Simulation Training on Call Center Agent Performance: A Field-Based Investigation

    OpenAIRE

    Nagesh N. Murthy; Goutam N. Challagalla; Leslie H. Vincent; Tasadduq A. Shervani

    2008-01-01

    The most prevalent form of training call center agents is via classroom instruction coupled with role-plays. Role-play training has a theoretical base in behavior modeling that entails observation, practice, and feedback. Emerging simulation-based technologies offer enhancements to behavior modeling that are absent in role-play training. This study evaluates the effectiveness of simulation-based training (henceforth, simulation training) as a behavior modeling technique vis-à-vis role-play tr...

  2. Terahertz signatures of biological-warfare-agent simulants

    Science.gov (United States)

    Globus, Tatiana; Woolard, Dwight L.; Khromova, Tatyana; Partasarathy, Ramakrishnan; Majewski, Alexander; Abreu, Rene; Hesler, Jeffrey L.; Pan, Shing-Kuo; Ediss, Geoff

    2004-09-01

    This work presents spectroscopic characterization results for biological simulant materials measured in the terahertz gap. Signature data have been collected between 3 cm-1 and 10 cm-1 for toxin Ovalbumin, bacteria Erwinia herbicola, Bacillus Subtilis lyophilized cells and RNA MS2 phage, BioGene. Measurements were conducted on a modified Bruker FTIR spectrometer equipped with the noise source developed in the NRAL. The noise source provides two orders of magnitude higher power in comparison with a conventional mercury lamp. Photometric characterization of the instrument performance demonstrates that the expected error for sample characterization inside the interval from 3 to 9.5 cm-1 is less then 1%.

  3. Multi-level behaviours in agent-based simulation: colonic crypt cell populations

    Science.gov (United States)

    Chen, Chih-Chun; Nagl, Sylvia B.; Clack, Christopher D.

    Agent-based modelling and simulation is now beginning to establish itself as a suitable technique for studying biological systems. However, a major issue in using agent-based simulations to study complex systems such as those in Systems Biology is the fact that simulations are `opaque'. While we have knowledge of individuals' behaviour through agent rules and have techniques for evaluating global behaviour by aggregating the states of individuals, methods for identifying the interactive mechanisms giving rise to this global behaviour are lacking. Formulating precise hypotheses about these multi-level behaviours is also difficult without an established formalism for describing them. The complex event formalism allows relationships between agent-rule-generated events to be defined so that behaviours at different levels of abstraction to be described. Complex event types define categories of these behaviours, which can then be detected in simulation, giving us computational method for distinguishing between alternative interactive mechanisms underlying a higher level behaviour. We apply the complex event formalism to an agent-based model of cell populations in the colonic crypt and demonstrate how competition and selection events can be identified in simulation at both the individual and clonal level, allowing us to computationally test hypotheses about the interactive mechanisms underlying a clone's success.

  4. AN AGENT-BASED SIMULATION ON MARKET CONSIDERING KNOWLEDGE TRANSITION AND SOCIAL IMPACT

    Institute of Scientific and Technical Information of China (English)

    Tieju Ma; Mina Ryoke; Yoshiteru Nakamori

    2002-01-01

    In this paper, an agent-based simulation about knowledge transition associated with social impact in market is introduced. In the simulation, the genetic algorithm is used to generate the next generation products and a dynamic social impact model is used to simulate how customers are influenced by other customers. The simulation and its results not only show some features and patterns of knowledge transition, but also explore and display some phenomena of business cultures. On the basis of the innovation model of knowledge-based economy, the transition between technical knowledge and products knowledge is discussed, and a fuzzy linear quantification model which can be used to simulate the transition is introduced.

  5. Agent based simulation as a novel decision support tool for retail managers

    OpenAIRE

    Siebers, Peer-Olaf; Aickelin, Uwe; Celia, Helen; Clegg, Chris

    2008-01-01

    Intelligent agents offer a new and exciting way of understanding the world of work. We apply agent-based simulation to investigate a set of problems in a retail context. Specifically, we are working to understand the relationship between human resource management practices and retail productivity. Our multi-disciplinary research team draws upon expertise from work psychologists and computer scientists. Our research so far has led us to conduct case study work with a top ten UK retailer....

  6. Multi-Agent Systems for the Simulation of Land Use Change and Policy Interventions

    OpenAIRE

    Schreinemachers, Pepijn; Berger, Thomas

    2008-01-01

    This chapter showed how MAS models can capture the complexities of human-environment systems. Two alternative designs of agent decision-making algorithms were discussed: heuristics and optimisation. On the basis of an empirical study on soil fertility decline in Uganda, it showed that both the designs can be combined. The empirical application furthermore illustrated the calibration and validation of the agent-based simulation models and their use as tools to explore the impact of alternative...

  7. Using an agent-based model to simulate children’s active travel to school

    OpenAIRE

    Yang, Yong; Diez-Roux, Ana V.

    2013-01-01

    Background Despite the multiple advantages of active travel to school, only a small percentage of US children and adolescents walk or bicycle to school. Intervention studies are in a relatively early stage and evidence of their effectiveness over long periods is limited. The purpose of this study was to illustrate the utility of agent-based models in exploring how various policies may influence children’s active travel to school. Methods An agent-based model was developed to simulate children...

  8. Agent based simulation as an exploratory tool in the study of the human dimension of combat

    OpenAIRE

    Brown, Lloyd Philip.

    2000-01-01

    War is a human phenomenon and the essence of war is a clash between human wills Ref. 10. The Marine Corps is applying complexity theory to study the human dimension of land warfare with the agent based combat simulation Irreducible Semi-Autonomous Adaptive Combat (ISAAC), developed by Andrew Ilachinski. ISAAC is designed to allow the user to explore the evolving patterns of large unit behavior that result from the collective interactions of individual agents. An urban and a desert scenario we...

  9. Resistance of Listeria monocytogenes Biofilms to Sanitizing Agents in a Simulated Food Processing Environment▿ †

    OpenAIRE

    Pan, Y.; Breidt, F.; Kathariou, S.

    2006-01-01

    The objective of this study was to evaluate the resistance of biofilms of Listeria monocytogenes to sanitizing agents under laboratory conditions simulating a food processing environment. Biofilms were initially formed on stainless steel and Teflon coupons using a five-strain mixture of L. monocytogenes. The coupons were then subjected to repeated 24-h daily cycles. Each cycle consisted of three sequential steps: (i) a brief (60 s) exposure of the coupons to a sanitizing agent (a mixture of p...

  10. Reactively and Anticipatory Behaving Agents for Artificial Life Simulations

    Science.gov (United States)

    Kohout, Karel; Nahodil, Pavel

    2010-11-01

    Reactive behavior is still considered and the exact opposite for the anticipatory one. Despite the advances on the field of anticipation there are little thoughts on relation with the reactive behavior, the similarities and where the boundary is. In this article we will present our viewpoint and we will try to show that reactive and anticipatory behavior can be combined. This is the basic ground of our unified theory for anticipatory behavior architecture. We still miss such compact theory, which would integrate multiple aspects of anticipation. My multi-level anticipatory behavior approach is based on the current understanding of anticipation from both the artificial intelligence and biology point of view. As part of the explanation we will also elaborate on the topic of weak and strong artificial life. Anticipation is not matter of a single mechanism in a living organism. It was noted already that it happens on many different levels even in the very simple creatures. What we consider to be important for our work and what is our original though is that it happens even without voluntary control. We believe that this is novelty though for the anticipation theory. Naturally research of anticipation was in the beginning of this decade focused on the anticipatory principles bringing advances on the field itself. This allowed us to build on those, look at them from higher perspective, and use not one but multiple levels of anticipation in a creature design. This presents second original though and that is composition of the agent architecture that has anticipation built in almost every function. In this article we will focus only on first two levels within the 8-factor anticipation framework. We will introduce them as defined categories of anticipation and describe them from theory and implementation algorithm point of view. We will also present an experiment conducted, however this experiment serves more as explanatory example. These first two levels may seem trivial

  11. Load Control Timescales Simulation in a Multi-Agent Smart Grid Platform

    DEFF Research Database (Denmark)

    Oliveira, Pedro; Gomes, Luis; Pinto, Tiago;

    2013-01-01

    to reduce peak demand. Aiming to support small players’ participation in demand response events, the Curtailment Service Provider emerged. This player works as an aggregator for demand response events. The control of small and medium players which act in smart grid and micro grid environments is enhanced...... with a multi-agent system with artificial intelligence techniques – the MASGriP (Multi-Agent Smart Grid Platform). Using strategic behaviours in each player, this system simulates the profile of real players by using software agents. This paper shows the importance of modeling these behaviours for studying...

  12. STUDIES ON HORIZONTAL COMPETITION AMONG HOMOGENOUS RETAILERS THROUGH AGENT-BASED SIMULATION

    Institute of Scientific and Technical Information of China (English)

    Ming XIE; Jian CHEN

    2004-01-01

    This paper adopts agent-based simulation to study the horizontal competition among homogenous price-setting retailers in a one-to-many supply chain (a supply chain consists of one supplier and multiple retailers). We model the supplier and retailers as agents, and design their behavioral rulesrespectively. The results show that although the agents learn individually based on their own experiences, the system converges asymptotically to near Nash equilibrium steady states.When analyzing the results, we first discuss the properties of these steady states. Then based on these properties, we analyze the effects of the retailers' horizontal competition on the retail prices, retailers'profits and supplier's revenue.

  13. An Agent-Based Simulation of In-Store Customer Experiences

    CERN Document Server

    Siebers, Peer-Olaf; Celia, Helen; Clegg, Christopher

    2008-01-01

    Agent-based modelling and simulation offers a new and exciting way of understanding the world of work. In this paper we describe the development of an agent-based simulation model, designed to help to understand the relationship between human resource management practices and retail productivity. We report on the current development of our simulation model which includes new features concerning the evolution of customers over time. To test some of these features we have conducted a series of experiments dealing with customer pool sizes, standard and noise reduction modes, and the spread of the word of mouth. Our multi-disciplinary research team draws upon expertise from work psychologists and computer scientists. Despite the fact we are working within a relatively novel and complex domain, it is clear that intelligent agents offer potential for fostering sustainable organisational capabilities in the future.

  14. Theoretical Proof of Unconditional Stability of the 3-D ADI-FDTD Method

    Institute of Scientific and Technical Information of China (English)

    WANG Yingjun; WANG Bingzhong; SHAO Wei

    2003-01-01

    In order to eliminate Courant-Friedrich-Levy(CFL) condition restraint and improve computational efficiency, a new finite-difference time-domain(FDTD) methodbased on the alternatingdirection implicit(ADI) technique is introduced recently. In this paper, a theoretical proof of the stability of the three-dimensional(3-D) ADI-FDTD method is presented. It is shown that the 3-D ADI-FDTD method is unconditionally stable and free from the CFL condition restraint.

  15. Simulation of an SNMP Agent: Operations, Analysis and Results

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar Sharma

    2012-09-01

    Full Text Available This paper aims at evaluate an SNMP environment on the basis of its operations and practical approaches. The SNMP protocol is used to monitor, control and configuring Network elements. Even though the SNMP technology is well documented but still it is relatively unclear how the SNMP is used in realpractice. This paper discusses about how the SNMP is deployed in a real network and how the traffic isanalyzed and controlled with the help of SNMP. With the continued improvements in the performance of the SNMP data collection, the developers of the SNMP based network monitoring system are applying their best effort in the system development. SNMP network management system development is an important aspect ofthe network management, and development process requires a lots of coordination with network environment, but it is too costly to construct a real network for development of network management system, so if we can provide a simulation network environment to develop a network management system, it will bring a great convenience for testing, training and other aspects of SNMP .

  16. Simulation of multi-agent joint firefighting and rescue operation%多 Agent 联合灭火救援作战仿真

    Institute of Scientific and Technical Information of China (English)

    刘静; 程桦

    2014-01-01

    A framework of multi-agent joint firefighting and rescue operation was proposed by applying the multi-agent theory and technology to studies on joint firefighting and rescue operation. It can realize information exchange between the commanders and display the interacted course of operation. Based on the description of command agent, operation agent and environment agent in the system, interaction rules between the agents and between the agent and environment were defined to describe the system’ s interrelation, a multi-agent coordination algorithm was given, and a joint firefighting and rescue simulation model was built. At last, a simulation is made on SWARM software to validate the proposed model.%将多 Agent 理论和技术应用于联合灭火救援作战的研究,构建了多 Agent 联合灭火救援作战模型框架,实现了联合灭火救援组织指挥相互之间的信息交换,显示了互相影响的行动过程。对系统中指挥 Agent、作战 Agent 和环境 Agent 进行描述,定义 Agent 之间以及 Agent 与环境之间的交互规则,来描述系统的相互关系,给出了多 Agent 的协同算法,并构建了联合灭火救援仿真模型。最后用多 Agent 软件工具集和通用软件平台(SWARM),采用 JAVA 语言编程,进行了模拟仿真,对文中构造的模型及相应机制进行了功能验证。

  17. Strategic bidding in electricity markets: An agent-based simulator with game theory for scenario analysis

    DEFF Research Database (Denmark)

    Pinto, Tiago; Praca, Isabel; Morais, Hugo;

    2013-01-01

    . MASCEM (Multi-Agent System for Competitive Electricity Markets) is a multi-agent electricity market simulator that models market players and simulates their operation in the market. The scenario analysis algorithm has been tested within MASCEM and our experimental findings with a case study based on real...... the behavior that better fits their objectives. This model includes forecasts of competitor players’ actions, to build models of their behavior, in order to define the most probable expected scenarios. Once the scenarios are defined, game theory is applied to support the choice of the ac-tion to be performed...

  18. Agent-based simulation of building evacuation using a grid graph-based model

    International Nuclear Information System (INIS)

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results

  19. Multi-Agent Model "Governor" For A Computer Simulation Of The Region As A Complex Socio-Economic System

    OpenAIRE

    Elena D. Sushko

    2013-01-01

    This paper describes the agent-based (multi-agent) model. Model simulates the socioeconomic condition of the region based on the reconstruction of its internal structure, as well as the structure and behavior in its territory of autonomous economic agents. An multi-agent model is an artificial society of interacting autonomous agents, each of them having a given set of personal characteristics ("resources") which define its value in the model in terms of its intended role in social production...

  20. Design and Simulation of Material-Integrated Distributed Sensor Processing with a Code-Based Agent Platform and Mobile Multi-Agent Systems

    Directory of Open Access Journals (Sweden)

    Stefan Bosse

    2015-02-01

    Full Text Available Multi-agent systems (MAS can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques.

  1. LUNES: Agent-based Simulation of P2P Systems (Extended Version)

    CERN Document Server

    D'Angelo, Gabriele

    2011-01-01

    We present LUNES, an agent-based Large Unstructured NEtwork Simulator, which allows to simulate complex networks composed of a high number of nodes. LUNES is modular, since it splits the three phases of network topology creation, protocol simulation and performance evaluation. This permits to easily integrate external software tools into the main software architecture. The simulation of the interaction protocols among network nodes is performed via a simulation middleware that supports both the sequential and the parallel/distributed simulation approaches. In the latter case, a specific mechanism for the communication overhead-reduction is used; this guarantees high levels of performance and scalability. To demonstrate the efficiency of LUNES, we test the simulator with gossip protocols executed on top of networks (representing peer-to-peer overlays), generated with different topologies. Results demonstrate the effectiveness of the proposed approach.

  2. A framework for service enterprise workflow simulation with multi-agents cooperation

    Science.gov (United States)

    Tan, Wenan; Xu, Wei; Yang, Fujun; Xu, Lida; Jiang, Chuanqun

    2013-11-01

    Process dynamic modelling for service business is the key technique for Service-Oriented information systems and service business management, and the workflow model of business processes is the core part of service systems. Service business workflow simulation is the prevalent approach to be used for analysis of service business process dynamically. Generic method for service business workflow simulation is based on the discrete event queuing theory, which is lack of flexibility and scalability. In this paper, we propose a service workflow-oriented framework for the process simulation of service businesses using multi-agent cooperation to address the above issues. Social rationality of agent is introduced into the proposed framework. Adopting rationality as one social factor for decision-making strategies, a flexible scheduling for activity instances has been implemented. A system prototype has been developed to validate the proposed simulation framework through a business case study.

  3. Modeling and Simulation on Co-evolution of Emergency Agents for Unconventional Emergency Water Disaster

    Directory of Open Access Journals (Sweden)

    Junfei Chen

    2012-09-01

    Full Text Available The Unconventional Emergency Water Disaster (UEWD is a water disaster that the society has not experienced or experienced few times and lacks the knowledge of its evolution and the experience to deal with it. The emergency system for UEWD is a complex adaptive system with different kinds of agents. In this study, we study the co-evolution mechanism of UEWD agents system. A dynamical model based on improved Logistic model and co-evolution theory is proposed. The impact factors of the emergency ability which mainly include the initial emergency capacity, the growth rate of the emergency ability, the maximun of the emergency ability, the quantity of the emergency agents and the coefficients of the competition and cooperation, is simulated and analyzed. The results show that the emergency ability under the co-stable state has nothing to do with the initial emergency capacity and the growth rate of the emergency ability. However, the time which reaches the co-stable state is positively related to the two factors. The maximun of the emergency ability and the quantity of the emergency agents have impacts on the emergency ability. The degree for the competition and cooperation among the agents is the key factor that affects the co-stable state of UEWD agents. At the end, some conclusions and suggestions are given to improve the emergency ability based on the characters of UEWD and the simulation results.

  4. FDTD analysis of ground-penetrating radar antennas with shields and absorbers

    Institute of Scientific and Technical Information of China (English)

    Liye LIU; Yi SU; Junjie MAO

    2008-01-01

    One of the most critical hardware components of a ground-penetrating radar (GPR) is the antenna system. Important parameters of antennas, such as antenna bandwidth, radiation waveform and cross coupling determine the GPR system performance. The modified TEM horn antenna with distributed resistor load is presented in this paper, and the radiation properties of the antenna with the shields and absorbers are studied through the three-dimensional finite-differ-ence time-domain (FDTD) scheme. Simulations show that the direct signal coupled from the transmitter is decreased by means of the shields and absorbers. Therefore, using the antenna in the GPR system can improve the signal-to-clutter ratio and the dynamic range of the system.

  5. Modelling and simulation of complex systems: an approach based on multi-level agents

    Directory of Open Access Journals (Sweden)

    Alain-Jerome Fougeres

    2011-11-01

    Full Text Available A complex system is made up of many components with many interactions. So the design of systems such as simulation systems, cooperative systems or assistance systems includes a very accurate modelling of interactional and communicational levels. The agent-based approach provides an adapted abstraction level for this problem. After having studied the organizational context and communicative capacities of agent-based systems, to simulate the reorganization of a flexible manufacturing, to regulate an urban transport system, and to simulate an epidemic detection system, our thoughts on the interactional level were inspired by human-machine interface models, especially those in cognitive engineering To provide a general framework for agent-based complex systems modelling, we then proposed a scale of four behaviours that agents may adopt in their complex systems (reactive, routine, cognitive, and collective. To complete the description of multi-level agent models, which is the focus of this paper, we illustrate our modelling and discuss our ongoing work on each level.

  6. The Italian Electricity Prices in Year 2025: an Agent-Based Simulation

    OpenAIRE

    Eric Guerci; Fulvio Fontini

    2012-01-01

    In this paper, we build a realistic large-scale agent-based model of the Italian dayahead-electricity market based on a genetic algorithm and validated over several weeks of 2010, on the basis of exact historical data about supply, demand and network characteristics. A statistical analysis confirms that the simulator well replicates the observed prices. A future scenario for the year 2025 is then simulated, which takes into account market's evolution and energy vectors' price dynamics. The fu...

  7. A high performance core for OSI management agents: implementation, simulation and performance evaluation

    OpenAIRE

    Rivalino, Matias Júnior

    1999-01-01

    This article presents a proposal of a multithreaded core for an OSI/ISO management agents including its modeling, simulation and performance evaluation. The proposed model i s compared against another one (unthreaded core) which is the commonly adopted model by the most of the network management systems. All the modeling and simulation process were done at the a gent core level. Therefore the performance evaluation do not consider any effect of the communication layers, dealing with the perfo...

  8. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    OpenAIRE

    Chassin, David P.; Jason C. Fuller; Ned Djilali

    2014-01-01

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies and the plethora of other resources and assets that are becoming part of modern electricity production, delivery and consumption systems. As a result, the US Department of Energy's Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D(TM) that uses an agent-based approach to simula...

  9. An Agent-Based Epidemic Simulation of Social Behaviors Affecting HIV Transmission among Taiwanese Homosexuals

    OpenAIRE

    Chung-Yuan Huang

    2015-01-01

    Computational simulations are currently used to identify epidemic dynamics, to test potential prevention and intervention strategies, and to study the effects of social behaviors on HIV transmission. The author describes an agent-based epidemic simulation model of a network of individuals who participate in high-risk sexual practices, using number of partners, condom usage, and relationship length to distinguish between high- and low-risk populations. Two new concepts—free links and fixed lin...

  10. Agent-based simulation and analysis of a defensive UAV swarm against an enemy UAV swarm

    OpenAIRE

    Munoz, Mauricio F.

    2011-01-01

    Unmanned systems, including unmanned combat aerial vehicles (UCAVs), are increasingly important in military operations. Given the growth of unmanned systems technology worldwide, these systems may increasingly pose a real threat to U.S. and Allied forces in the near future. This thesis proposes a future concept of employing a defensive UCAV swarm, launched from a friendly sea-based platform. To simulate this defensive swarm system, an agent-based simulation model was developed, and approp...

  11. Agent-based evacuation simulation for spatial allocation assessment of urban shelters

    Science.gov (United States)

    Yu, Jia; Wen, Jiahong; Jiang, Yong

    2015-12-01

    The construction of urban shelters is one of the most important work in urban planning and disaster prevention. The spatial allocation assessment is a fundamental pre-step for spatial location-allocation of urban shelters. This paper introduces a new method which makes use of agent-based technology to implement evacuation simulation so as to conduct dynamic spatial allocation assessment of urban shelters. The method can not only accomplish traditional geospatial evaluation for urban shelters, but also simulate the evacuation process of the residents to shelters. The advantage of utilizing this method lies into three aspects: (1) the evacuation time of each citizen from a residential building to the shelter can be estimated more reasonably; (2) the total evacuation time of all the residents in a region is able to be obtained; (3) the road congestions in evacuation in sheltering can be detected so as to take precautionary measures to prevent potential risks. In this study, three types of agents are designed: shelter agents, government agents and resident agents. Shelter agents select specified land uses as shelter candidates for different disasters. Government agents delimitate the service area of each shelter, in other words, regulate which shelter a person should take, in accordance with the administrative boundaries and road distance between the person's position and the location of the shelter. Resident agents have a series of attributes, such as ages, positions, walking speeds, and so on. They also have several behaviors, such as reducing speed when walking in the crowd, helping old people and children, and so on. Integrating these three types of agents which are correlated with each other, evacuation procedures can be simulated and dynamic allocation assessment of shelters will be achieved. A case study in Jing'an District, Shanghai, China, was conducted to demonstrate the feasibility of the method. A scenario of earthquake disaster which occurs in nighttime

  12. Identification of a Common Binding Mode for Imaging Agents to Amyloid Fibrils from Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Skeby, Katrine Kirkeby; Sørensen, Jesper; Schiøtt, Birgit

    2013-01-01

    amyloid fibrils and the disease pathology. Alzheimer’s disease is very difficult to diagnose, and much research is being performed to develop noninvasive diagnostic methods, such as imaging with small-molecule agents. The interactions between amyloid fibrils and imaging agents are challenging to examine...... experimentally due to the insoluble nature of amyloid fibrils. This study uses molecular dynamics simulations to investigate the interactions between 13 aromatic amyloid imaging agents, entailing 4 different organic scaffolds, and a model of an amyloid fibril. Clustering analysis combined with free energy...... binding modes for imaging agents is proposed to originate from subtle differences in amino acid composition of the surface grooves on an amyloid fibril, resulting in fine tuning of the binding affinities for a specific amyloid fibril....

  13. New development in Anticipatory Agent System used for Power Management in Smart Home Simulator

    Directory of Open Access Journals (Sweden)

    Ahmed Elmahalawy

    2012-03-01

    Full Text Available In recent years, there is a global evolution in the way energy is generated and consumed due to climate change, energy independence and the impending decay of fossil fuels. It has seen a rise of interest in the deployment of multi agent systems in energy domains that inherently have uncertain and dynamic environments with limited resources. In such domains, the key challenge is to minimize the energy consumption while satisfying the comfort level of occupants in the buildings under uncertainty (regarding agent negotiation actions. This paper presents the new development for enhancement the performance of Power Management in Smart Home simulator. This development is based on the anticipatory and multi agent systems that used in this simulator.

  14. Islamic Economics in a Complex World: Explorations in Agent-based Simulation (Research Paper)

    OpenAIRE

    Al-Suwailem, Sami Ibrahim

    2008-01-01

    This paper suggests that complexity theory provides an alternative paradigm to the Neoclassical framework widely adopted in economic studies. It states that the new paradigm calls for a different methodology than the one used by the mainstream: agent-based simulation allows for exploring rich and highly complex problems in an intuitive and systematic manner.

  15. Metal organic frameworks (MOFs) for degrdation of nerve agent simulant parathion

    Science.gov (United States)

    Parathion, a simulant of nerve agent VX, has been studied for degradation on Fe3+, Fe2+ and zerovalent iron supported on chitosan. Chitosan, a naturally occurring biopolymer derivative of chitin, is a very good adsorbent for many chemicals including metals. Chitosan is used as supporting biopolymer ...

  16. Fluorogenic and chromogenic probe for rapid detection of a nerve agent simulant DCP.

    Science.gov (United States)

    Wu, Wei-hui; Dong, Jun-jun; Wang, Xin; Li, Jian; Sui, Shao-hui; Chen, Gao-yun; Liu, Ji-wei; Zhang, Ming

    2012-07-21

    A fluorogenic and visual probe was devised to detect diethyl chlorophosphate (DCP), a nerve agent simulant. The probe, N-(rhodamine B)-lactam-2-aminoethanol (RB-AE), undergoes oxazoline formation following phosphorylation in the presence of DCP, which gives rapid and clear fluorescence and color change in the assay solutions. PMID:22624148

  17. Multi-GPU and multi-CPU accelerated FDTD scheme for vibroacoustic applications

    Science.gov (United States)

    Francés, J.; Otero, B.; Bleda, S.; Gallego, S.; Neipp, C.; Márquez, A.; Beléndez, A.

    2015-06-01

    The Finite-Difference Time-Domain (FDTD) method is applied to the analysis of vibroacoustic problems and to study the propagation of longitudinal and transversal waves in a stratified media. The potential of the scheme and the relevance of each acceleration strategy for massively computations in FDTD are demonstrated in this work. In this paper, we propose two new specific implementations of the bi-dimensional scheme of the FDTD method using multi-CPU and multi-GPU, respectively. In the first implementation, an open source message passing interface (OMPI) has been included in order to massively exploit the resources of a biprocessor station with two Intel Xeon processors. Moreover, regarding CPU code version, the streaming SIMD extensions (SSE) and also the advanced vectorial extensions (AVX) have been included with shared memory approaches that take advantage of the multi-core platforms. On the other hand, the second implementation called the multi-GPU code version is based on Peer-to-Peer communications available in CUDA on two GPUs (NVIDIA GTX 670). Subsequently, this paper presents an accurate analysis of the influence of the different code versions including shared memory approaches, vector instructions and multi-processors (both CPU and GPU) and compares them in order to delimit the degree of improvement of using distributed solutions based on multi-CPU and multi-GPU. The performance of both approaches was analysed and it has been demonstrated that the addition of shared memory schemes to CPU computing improves substantially the performance of vector instructions enlarging the simulation sizes that use efficiently the cache memory of CPUs. In this case GPU computing is slightly twice times faster than the fine tuned CPU version in both cases one and two nodes. However, for massively computations explicit vector instructions do not worth it since the memory bandwidth is the limiting factor and the performance tends to be the same than the sequential version

  18. GPU-Accelerated Parallel FDTD on Distributed Heterogeneous Platform

    Directory of Open Access Journals (Sweden)

    Ronglin Jiang

    2014-01-01

    Full Text Available This paper introduces a (finite difference time domain FDTD code written in Fortran and CUDA for realistic electromagnetic calculations with parallelization methods of Message Passing Interface (MPI and Open Multiprocessing (OpenMP. Since both Central Processing Unit (CPU and Graphics Processing Unit (GPU resources are utilized, a faster execution speed can be reached compared to a traditional pure GPU code. In our experiments, 64 NVIDIA TESLA K20m GPUs and 64 INTEL XEON E5-2670 CPUs are used to carry out the pure CPU, pure GPU, and CPU + GPU tests. Relative to the pure CPU calculations for the same problems, the speedup ratio achieved by CPU + GPU calculations is around 14. Compared to the pure GPU calculations for the same problems, the CPU + GPU calculations have 7.6%–13.2% performance improvement. Because of the small memory size of GPUs, the FDTD problem size is usually very small. However, this code can enlarge the maximum problem size by 25% without reducing the performance of traditional pure GPU code. Finally, using this code, a microstrip antenna array with 16×18 elements is calculated and the radiation patterns are compared with the ones of MoM. Results show that there is a well agreement between them.

  19. Comparative Study of FDTD-Adopted Numerical Algorithms for Kerr Nonlinearities

    DEFF Research Database (Denmark)

    Maksymov, Ivan S.; Sukhorukov, Andrey A.; Lavrinenko, Andrei;

    2011-01-01

    Accurate finite-difference time-domain (FDTD) modeling of optical pulse propagation in nonlinear media usually implies the use of auxiliary differential equation (ADE) techniques. The updating of electric field in full-vectorial 3-D ADE FDTD modeling of the optical Kerr effect and two...

  20. Multi-agent simulation of competitive electricity markets: Autonomous systems cooperation for European market modeling

    International Nuclear Information System (INIS)

    Highlights: • Definition of an ontology allowing the communication between multi-agents systems. • Social welfare evaluation in different electricity markets. • Demonstration of the use of the proposed ontology between two multi-agents systems. • Strategic biding in electricity markets. • European electricity markets comparison. - Abstract: The electricity market restructuring, and its worldwide evolution into regional and even continental scales, along with the increasing necessity for an adequate integration of renewable energy sources, is resulting in a rising complexity in power systems operation. Several power system simulators have been developed in recent years with the purpose of helping operators, regulators, and involved players to understand and deal with this complex and constantly changing environment. The main contribution of this paper is given by the integration of several electricity market and power system models, respecting to the reality of different countries. This integration is done through the development of an upper ontology which integrates the essential concepts necessary to interpret all the available information. The continuous development of Multi-Agent System for Competitive Electricity Markets platform provides the means for the exemplification of the usefulness of this ontology. A case study using the proposed multi-agent platform is presented, considering a scenario based on real data that simulates the European Electricity Market environment, and comparing its performance using different market mechanisms. The main goal is to demonstrate the advantages that the integration of various market models and simulation platforms have for the study of the electricity markets’ evolution

  1. A parallel computational FDTD approach to the analysis of the light scattering from an opal photonic crystal

    Science.gov (United States)

    Vaccari, A.; Cala'Lesina, A.; Cristoforetti, L.; Chiappini, A.; Prudenzano, F.; Bozzoli, A.; Ferrari, M.

    2013-05-01

    This paper describes the parallel computational approach for the analysis of the multiple scattering of light from a three dimensional ensemble of many spherical particles having an ordered face-centered cubic lattice structure. The solution is obtained by numerically solving the Maxwell's equations using the FDTD (Finite Difference Time Domain) method with an impinging electromagnetic plane. The aim is to simulate the reflectance and transmittance of the system in the 300÷700 nm wavelength range, calculating also the angular power distribution of the scattered light. This study is suitable for the optical characterization of opal photonic crystals.

  2. A SIMULATION OF AGENT-BASED MODELS FOR HIGH FREQUENCY TRADING ON THE STOCK EXCHANGE MARKET

    OpenAIRE

    Diana Dezsi

    2013-01-01

    High frequency computer-based trading (HFT) represents a challenging topic nowadays, mainly due to the controversy it creates among investors on the financial market. The hereto paper uses two types of agent-based models, one with zero-intelligence traders and the other with intelligent traders in order to simulate the tick-by-tick high frequency trading market for ten US stocks. The results show that in almost all the cases the intelligent agent-based model performed better when compared to ...

  3. Evaluating Government's Policies on Promoting Smart Metering in Retail Electricity Markets via Agent Based Simulation

    OpenAIRE

    Zhang, Tao; Nuttall, William J.

    2008-01-01

    In this paper, we develop an agent-based model of a market game in order to evaluate the effectiveness of the UK government’s 2008-2010 policy on promoting smart metering. We also consider possible supplementary strategies. With the model, we test the effectiveness of four possible strategy options and suggest their policy implications. The context of the paper is a practical application of agent-based simulation to the retail electricity market in Britain. The contribution of the research ar...

  4. REGLES DE RECHERCE D\\'INFORMATION SUR L\\'INTERNET: SIMULATION AGENTS INTELLIGENTS

    Directory of Open Access Journals (Sweden)

    Dorin Militaru

    2007-10-01

    Full Text Available Les agents de recherche disponibles sur l’Internet sont des outils permettant aux consommateurs de comparer les prix d’un produit proposé par différents vendeurs. Les agents existants basent leur recherche sur une liste prédéfinie de vendeurs ŕ consulter, autrement dit, ils utilisent une rčgle de recherche avec une taille d’échantillon fixe (agent de recherche FSS. Toutefois, dans le futur, avec la mise en place de nouveaux systčmes de tarification des communications sur le réseau, cette rčgle de recherche est susceptible d’évoluer vers d’autres rčgles plus flexibles permettrant aux agents de faire un arbitrage entre les coűts de communication et le prix trouvé. Dans ce cadre, la rčgle de recherche séquentielle optimale (agent de recherche RP est une alternative possible. Néanmoins, son adoption va dépendre fortement de ses performances espérées. Dans cet article, nous analysons les performances relatives d’agents RP et FSS sur un marché oů l’accčs ŕ l’information est coűteux. A l’équilibre théorique du marché, nous montrons que les agents de recherche RP permettent toujours aux consommateurs de payer des coűts totaux moins élevés. Dans un second temps, nous testons la robustesse de ce résultat théorique en simulant un marché sur lequel les agents de recherche RP et les vendeurs n’ont qu’une information partielle sur sa structure.

  5. Simulating Transport and Land Use Interdependencies for Strategic Urban Planning—An Agent Based Modelling Approach

    Directory of Open Access Journals (Sweden)

    Nam Huynh

    2015-10-01

    Full Text Available Agent based modelling has been widely accepted as a promising tool for urban planning purposes thanks to its capability to provide sophisticated insights into the social behaviours and the interdependencies that characterise urban systems. In this paper, we report on an agent based model, called TransMob, which explicitly simulates the mutual dynamics between demographic evolution, transport demands, housing needs and the eventual change in the average satisfaction of the residents of an urban area. The ability to reproduce such dynamics is a unique feature that has not been found in many of the like agent based models in the literature. TransMob, is constituted by six major modules: synthetic population, perceived liveability, travel diary assignment, traffic micro-simulator, residential location choice, and travel mode choice. TransMob is used to simulate the dynamics of a metropolitan area in South East of Sydney, Australia, in 2006 and 2011, with demographic evolution. The results are favourably compared against survey data for the area in 2011, therefore validating the capability of TransMob to reproduce the observed complexity of an urban area. We also report on the application of TransMob to simulate various hypothetical scenarios of urban planning policies. We conclude with discussions on current limitations of TransMob, which serve as suggestions for future developments.

  6. A water market simulator considering pair-wise trades between agents

    Science.gov (United States)

    Huskova, I.; Erfani, T.; Harou, J. J.

    2012-04-01

    In many basins in England no further water abstraction licences are available. Trading water between water rights holders has been recognized as a potentially effective and economically efficient strategy to mitigate increasing scarcity. A screening tool that could assess the potential for trade through realistic simulation of individual water rights holders would help assess the solution's potential contribution to local water management. We propose an optimisation-driven water market simulator that predicts pair-wise trade in a catchment and represents its interaction with natural hydrology and engineered infrastructure. A model is used to emulate licence-holders' willingness to engage in short-term trade transactions. In their simplest form agents are represented using an economic benefit function. The working hypothesis is that trading behaviour can be partially predicted based on differences in marginal values of water over space and time and estimates of transaction costs on pair-wise trades. We discuss the further possibility of embedding rules, norms and preferences of the different water user sectors to more realistically represent the behaviours, motives and constraints of individual licence holders. The potential benefits and limitations of such a social simulation (agent-based) approach is contrasted with our simulator where agents are driven by economic optimization. A case study based on the Dove River Basin (UK) demonstrates model inputs and outputs. The ability of the model to suggest impacts of water rights policy reforms on trading is discussed.

  7. Developing an Agent-Based Model to Simulate Urban Land-Use Expansion (Case Study: Qazvin

    Directory of Open Access Journals (Sweden)

    F. Nourian

    2012-01-01

    Full Text Available Extended abstract1-IntroductionUrban land-use expansion is a challenging issue in developing countries. Increases in population as well as the immigration from the villages to the cities are the two major factors for that phenomenon. Those factors have reduced the influence of efforts that try to limit the cities’ boundaries. Thus, spatial planners always look for the models that simulate the expansion of urban land-uses and enable them to prevent unbalanced expansions of cities and guide the developments to the desired areas. Several models have been developed and evaluated for simulating urban land-use expansions. Despite the variety of the models, most of them have focused on simulating urban land-use expansions just around a city. Thus, the regional models that consider wider area are of primary importance.2- Theoretical basesIn this study a new agent-based model has been developed and implemented to simulate urban land-use expansion in Qazvin and Alborz regions of Qazvin state which have an area of 1620 square kilometers. In this model, land-use developers have been treated as agents that move in the landscape explicitly and assess the state of parcels for development. So, the environment of the model is raster. The agents are developed into five groups which have different aims. The agents may fall in competition to develop the same parcels. Moreover, due to the spatial essence of the problem, GIS were used to prepare the environment of agents’ movement and search and to aggregate and analyze the results.Two main steps can be recognized in this model: the Searching step and the Development step:Searching step: The agents are created and distributed in the districts. The selection of districts is probabilistic and is based on the primary probability of selection, assumed for districts. When agents go to the districts, at first they move randomly to the neighborhood of pre-developed areas. Wherever the agent starts its activities, it

  8. An Agent-Based Model of New Venture Creation: Conceptual Design for Simulating Entrepreneurship

    Science.gov (United States)

    Provance, Mike; Collins, Andrew; Carayannis, Elias

    2012-01-01

    There is a growing debate over the means by which regions can foster the growth of entrepreneurial activity in order to stimulate recovery and growth of their economies. On one side, agglomeration theory suggests the regions grow because of strong clusters that foster knowledge spillover locally; on the other side, the entrepreneurial action camp argues that innovative business models are generated by entrepreneurs with unique market perspectives who draw on knowledge from more distant domains. We will show you the design for a novel agent-based model of new venture creation that will demonstrate the relationship between agglomeration and action. The primary focus of this model is information exchange as the medium for these agent interactions. Our modeling and simulation study proposes to reveal interesting relationships in these perspectives, offer a foundation on which these disparate theories from economics and sociology can find common ground, and expand the use of agent-based modeling into entrepreneurship research.

  9. Simulating tissue mechanics with agent-based models: concepts, perspectives and some novel results

    Science.gov (United States)

    Van Liedekerke, P.; Palm, M. M.; Jagiella, N.; Drasdo, D.

    2015-12-01

    In this paper we present an overview of agent-based models that are used to simulate mechanical and physiological phenomena in cells and tissues, and we discuss underlying concepts, limitations, and future perspectives of these models. As the interest in cell and tissue mechanics increase, agent-based models are becoming more common the modeling community. We overview the physical aspects, complexity, shortcomings, and capabilities of the major agent-based model categories: lattice-based models (cellular automata, lattice gas cellular automata, cellular Potts models), off-lattice models (center-based models, deformable cell models, vertex models), and hybrid discrete-continuum models. In this way, we hope to assist future researchers in choosing a model for the phenomenon they want to model and understand. The article also contains some novel results.

  10. Pattern-oriented Agent-based Monte Carlo simulation of Cellular Redox Environment

    DEFF Research Database (Denmark)

    Tang, Jiaowei; Holcombe, Mike; Boonen, Harrie C.M.

    . Because complex networks and dynamics of redox still is not completely understood , results of existing experiments will be used to validate the modeling according to ideas in pattern-oriented agent-based modeling[8]. The simulation of this model is computational intensive, thus an application 'FLAME......] could be very important factors. In our project, an agent-based Monte Carlo modeling [6] is offered to study the dynamic relationship between extracellular and intracellular redox and complex networks of redox reactions. In the model, pivotal redox-related reactions will be included, and the reactants...... cells. Biochimica Et Biophysica Acta-General Subjects, 2008. 1780(11): p. 1271-1290. 5. Jones, D.P., Redox sensing: orthogonal control in cell cycle and apoptosis signalling. J Intern Med, 2010. 268(5): p. 432-48. 6. Pogson, M., et al., Formal agent-based modelling of intracellular chemical interactions...

  11. 基于HLA的Agent-DEVS协同仿真建模%Collaborative modeling and simulation of Agent-DEVS based on HLA

    Institute of Scientific and Technical Information of China (English)

    曹琦; 何中市; 余磊

    2011-01-01

    In order to extend the DEVS with abilities of intelligent modeling and distributed simulation, a collaborative modeling and simulation method for Agent-DEVS based on HLA was studied. The formal description of Agent-DEVS federate models based on ParalIeI-DEVS was proposed. The models ports in Agent-DEVS were translated into data objects in HLA and the structure of the models was given. The communication mechanism was analyzed. The mapping between knowledge update in Agent-DEVS and attribute update in HLA, and that between models coupling in Agent-DEVS and instances interaction in HLA, were established respectively. Finally, the modeling and simulation application for material supply in emergent disaster was put forward. The results show that the reusability of Agent-DEVS models is enhanced by HLA and the interoperability of the models is enriched by knowledge update mechanism. In addition, the autonomy and independent ability for transaction processing are improved significantly.%为实现DEVS在智能建模与分布仿真能力方面的扩充,研究了基于HLA的Agent-DEVS协同仿真建模方法.以并行DEVS为基础,提出了Agent-DEVS联邦模型的形式化描述;将Agent-DEVS模型端口转换为HLA数据对象,确定了Agent-DEVS联邦模型结构,并分析了通信机制,分别建立了Agent-DEVS的知识更新与HLA的属性更新间的映射,以及Agent-DEVS的模型耦合与HLA的实例交互间的映射;最后结合抢险救灾物资保障的仿真建模进行了应用.结果表明,HLA体系框架增强了Agent-DEVS模型的可重用性;知识更新机制丰富了Agent-DEVS模型的互操作性;同时,Agent-DEVS模型的自治性与独立事务处理能力得到了进一步提高.

  12. Evolutionary Agent-Based Simulation of the Introduction of New Technologies in Air Traffic Management

    Science.gov (United States)

    Yliniemi, Logan; Agogino, Adrian K.; Tumer, Kagan

    2014-01-01

    Accurate simulation of the effects of integrating new technologies into a complex system is critical to the modernization of our antiquated air traffic system, where there exist many layers of interacting procedures, controls, and automation all designed to cooperate with human operators. Additions of even simple new technologies may result in unexpected emergent behavior due to complex human/ machine interactions. One approach is to create high-fidelity human models coming from the field of human factors that can simulate a rich set of behaviors. However, such models are difficult to produce, especially to show unexpected emergent behavior coming from many human operators interacting simultaneously within a complex system. Instead of engineering complex human models, we directly model the emergent behavior by evolving goal directed agents, representing human users. Using evolution we can predict how the agent representing the human user reacts given his/her goals. In this paradigm, each autonomous agent in a system pursues individual goals, and the behavior of the system emerges from the interactions, foreseen or unforeseen, between the agents/actors. We show that this method reflects the integration of new technologies in a historical case, and apply the same methodology for a possible future technology.

  13. ActivitySim: large-scale agent based activity generation for infrastructure simulation

    Energy Technology Data Exchange (ETDEWEB)

    Gali, Emmanuel [Los Alamos National Laboratory; Eidenbenz, Stephan [Los Alamos National Laboratory; Mniszewski, Sue [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory; Teuscher, Christof [PORTLAND STATE UNIV

    2008-01-01

    The United States' Department of Homeland Security aims to model, simulate, and analyze critical infrastructure and their interdependencies across multiple sectors such as electric power, telecommunications, water distribution, transportation, etc. We introduce ActivitySim, an activity simulator for a population of millions of individual agents each characterized by a set of demographic attributes that is based on US census data. ActivitySim generates daily schedules for each agent that consists of a sequence of activities, such as sleeping, shopping, working etc., each being scheduled at a geographic location, such as businesses or private residences that is appropriate for the activity type and for the personal situation of the agent. ActivitySim has been developed as part of a larger effort to understand the interdependencies among national infrastructure networks and their demand profiles that emerge from the different activities of individuals in baseline scenarios as well as emergency scenarios, such as hurricane evacuations. We present the scalable software engineering principles underlying ActivitySim, the socia-technical modeling paradigms that drive the activity generation, and proof-of-principle results for a scenario in the Twin Cities, MN area of 2.6 M agents.

  14. A multi-agent approach for modeling oligarchs' campaign donations with simulated spatial elections

    CERN Document Server

    Wright, Mason

    2013-01-01

    We present the OLIGO model, a multi-agent simulation of oligarchy. We extend previous multi-agent-based, spatial models of democracy by adding a new class of agents, oligarchs, which represent leaders of firms in a common industry who lobby for beneficial subsidies through campaign donations. We test hypotheses from the literature in political economics on the behavior of oligarchs and political parties as they interact, under conditions of imperfect information and bounded rationality. By verifying that central hypotheses from the economics literature hold for the OLIGO model, we accomplish two goals: (1) We show that the simple rules agents follow in our model are sufficient to capture much of the complex dynamics of this politico-economic system; (2) we validate these results from prior studies that used analytic methods, using an alternative, agent-based modeling method; and (3) we derive support for the claim that the OLIGO model is a useful test environment for novel hypotheses about oligarchs' campaign...

  15. Simulation of Land-Use Development, Using a Risk-Regarding Agent-Based Model

    Directory of Open Access Journals (Sweden)

    F. Hosseinali

    2012-01-01

    Full Text Available The aim of this paper is to study the spatial consequences of applying different Attitude Utility Functions (AUFs, which reflect peoples’ simplified psychological frames, to investment plans in land-use decision making. For this purpose, we considered and implemented an agent-based model with new methods for searching landscapes, for selecting parcels to develop, and for allowing competitions among agents. Besides this, GIS (Geographic Information Systems as a versatile and powerful medium of analyzing and representing spatial data is used. Our model is implemented on an artificial landscape in which land is being developed by agents. The agents are assumed to be mobile developers that are equipped with several land-related objectives. In this paper, agents mimic various risk-bearing attitudes and sometimes compete for developing the same parcel. The results reveal that patterns of land-use development are different in the two cases of regarding and disregarding AUFs. Therefore, it is considered here that using the attitudes of people towards risk helps the model to better simulate the decision making of land-use developers. The different attitudes toward risk used in this study can be attributed to different categories of developers based on sets of characteristics such as income, age, or education.

  16. Changing crops in response to climate: virtual Nang Rong, Thailand in an agent based simulation

    OpenAIRE

    Malanson, George P.; Verdery, Ashton M.; Walsh, Stephen J.; Sawangdee, Yothin; Heumann, Benjamin W.; McDaniel, Philip M.; Frizzelle, Brian G.; Williams, Nathalie E.; Yao, Xiaozheng; Entwisle, Barbara; Rindfuss, Ronald R.

    2014-01-01

    The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely economic outcomes, but included elements of bounded rationality in dependence on household demography. The socioeconomic dynamics are endogenous i...

  17. An Evolutionary Agent-based simulation model for the industry life cycle

    OpenAIRE

    Lehmann-Waffenschmidt, B. Cornelia

    2008-01-01

    In contrast to the usual approach taken in the literature, in which an Industry Life Cycle (ILC) is reproduced by aggregate functions, the model of this paper generates a self-organizing ILC. A general evolutionary agent-based simulation model is developed that can be adapted for specific branches of industry. The results enable conclusions to be drawn for competition policy with regard to the workability of competition in the various phases of the ILC.

  18. MOSAIIC : City-Level Agent-Based Traffic Simulation Adapted to Emergency Situations

    OpenAIRE

    Czura, Guillaume; Taillandier, Patrick; Tranouez, Pierrick; Daudé, Éric

    2015-01-01

    International audience In this paper, we present MOSAIIC, an agent-based model to simulate the road traffic of a city in the context of a catastrophic event. Whether natural (cyclone, earthquake, flood) or human (industrial accident) in origin, catastrophic situations modify both infrastructures (buildings, road networks) and human behaviors, which can have a huge impact on human safety. Because the heterogeneities of human behaviors, of land- uses and of network topology have a great impa...

  19. Agent-Based simulation as a useful tool for the study of markets

    OpenAIRE

    Rouchier, Juliette

    2008-01-01

    This paper explores diverse dimensions of the use of agent-based simulation used for the analysis of market dynamics. The literature that is studied is in majority related to economics theory, but can also be part of marketing studies. The main point in this reearch is the focus that authors put on learning, diffusion, imitation and bouded rationality. Markets are seen through several sub-divisions, such as: buyer-seller interpersonal relationship; views on the global chain, including consume...

  20. Agent based simulation framework for quantitative and qualitative social research: Statistics and natural language generation

    OpenAIRE

    Arroyo Menéndez, Millán; Hassan Collado, Samer; León, Carlos; Pavón Mestres, Juan Luis

    2007-01-01

    Even though Agent Based Social Simulation is beginning to be spread out as a powerful quantitative method for sociologists, it is still far from attracting qualitative ones. We propose to broaden ABSS horizons with a system that returns outputs useful for both paradigms. The case used as example is the study of the evolution of religiosity in the Spanish post-modern society. From a “macro” perspective, it analyses social trends, using quantitative data from the European Values Survey and givi...

  1. SCENARIO ANALYSIS OF TECHNOLOGY PRODUCTS WITH AN AGENT-BASED SIMULATION AND DATA MINING FRAMEWORK

    OpenAIRE

    AMIT SHINDE; MOEED HAGHNEVIS; Janssen, Marco A.; GEORGE C. RUNGER; MANI JANAKIRAM

    2013-01-01

    A framework is presented to simulate and analyze the effect of multiple business scenarios on the adoption behavior of a group of technology products. Diffusion is viewed as an emergent phenomenon that results from the interaction of consumers. An agent-based model is used in which potential adopters of technology product are allowed to be influenced by their local interactions within the social network. Along with social influence, the effect of product features is important and we ascribe f...

  2. SimCode: Agent-based Simulation Modelling of Open-Source Software Development

    OpenAIRE

    Jean-Michel Dalle; David, Paul A.

    2005-01-01

    We present an original modeling tool, which can be used to study the mechanisms by which free/libre and open source software developers’ code-writing efforts are allocated within open source projects. It is first described analytically in a discrete choice framework, and then simulated using agent-based experiments. Contributions are added sequentially to either existing modules, or to create new modules out of existing ones: as a consequence, the global emerging architecture forms a hierarch...

  3. AGENT-BASED SIMULATION OF CONSUMER DEMAND FOR SMART METERING TARIFFS

    OpenAIRE

    MARTIN RIXEN; JÜRGEN WEIGAND

    2013-01-01

    An agent-based model simulates consumer demand for smart metering tariffs. It utilizes the Bass Diffusion Model and Rogers's adopter categories to locate demand-side barriers and drivers. Integration of empirical census microdata enables a validated socio-economic background for each consumer. The key performance indicators diffusion-speed and diffusion-level measure the effectiveness of regulatory interventions to induce diffusion. Pricing, promotion and quantity-regulation policies are test...

  4. FDTD Analysis of Nonuniform Lossy Cascade Multiconductor Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    付继伟; 侯朝桢; 窦丽华

    2004-01-01

    A hybrid algorithm is presented for nonuniform lossy multiconductor transmission lines (MTL) connected by arbitrary linear load networks. The networks are characterized by a state-variable equation which allows a general characterization of dynamic elements in the cascade networks. The method is achieved by the finite difference-time domain (FDTD) algorithm for the MTL, and the skin effect is taken into account, the more accurate method is used to compute the skin effect. And this method is combined with the computation of the nonuniform transmission lines. Finally, several numerical examples are given, these results indicate that: the current of the lossy MTL is smaller than the lossless of the MTL; and when the load networks contain the dynamic element, the transition time of the current is longer than the MTL connected by resistance only.

  5. Agent-Based Simulation of Business Processes in a Virtual World

    Czech Academy of Sciences Publication Activity Database

    Bošanský, Branislav; Brom, C.

    Berlin: Springer, 2008 - (Corchado, E.; Abraham, A.; Pedrycz, W.), s. 86-94. (Lecture Notes in Artficial Intelligence . 5271). ISBN 978-3-540-87655-7. [HIAS. International Workshop /3./. Burgos (ES), 24.09.2008-26.09.2008] R&D Projects: GA MŠk(CZ) 1M06014; GA AV ČR 1ET100300517 Institutional research plan: CEZ:AV0Z10300504 Keywords : agent-based simulations * business process simulation * business process modelling Subject RIV: IN - Informatics, Computer Science

  6. Agent-Based Simulation of Mass Shootings: Determining How to Limit the Scale of a Tragedy

    OpenAIRE

    Roy Hayes; Reginald Hayes

    2014-01-01

    An agent-based simulation was created to examine key parameters in mass shootings. The goal of the simulation was to examine the potential effectiveness of Senator Dianne Feinstein’s (D-Calif.) assault weapons and high-capacity magazines bill. Based on the analysis, the proposed law would have a negligible effect on the number of people shot during mass shootings. The assault weapons portion of the proposed bill will have no effect on the number of people killed or wounded in a mass shootin...

  7. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    Directory of Open Access Journals (Sweden)

    David P. Chassin

    2014-01-01

    Full Text Available Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control system design, and integration of wind power in a smart grid.

  8. To Develop a Database Management Tool for Multi-Agent Simulation Platform

    OpenAIRE

    Truong, Minh Thai

    2015-01-01

    Depuis peu, la Modélisation et Simulation par Agents (ABMs) est passée d'une approche dirigée par les modèles à une approche dirigée par les données (Data Driven Approach, DDA). Cette tendance vers l’utilisation des données dans la simulation vise à appliquer les données collectées par les systèmes d’observation à la simulation (Edmonds and Moss, 2005; Hassan, 2009). Dans la DDA, les données empiriques collectées sur les systèmes cibles sont utilisées non seulement pour la simulation des modè...

  9. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    Energy Technology Data Exchange (ETDEWEB)

    Chassin, David P.; Fuller, Jason C.; Djilali, Ned

    2014-06-23

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control system design, and integration of wind power in a smart grid.

  10. Agent-based modeling and simulation of clean heating system adoption in Norway

    Energy Technology Data Exchange (ETDEWEB)

    Sopha, Bertha Maya

    2011-03-15

    A sound climate policy encouraging clean energy investment is important to mitigate global warming. Previous research has demonstrated that consumer choice indeed plays an important role in adoption of sustainable technologies. This thesis strives to gain a better understanding of consumers' decision-making on heating systems and to explore the potential application of agent-based modeling (ABM) in exploring mechanism underlying adoption in which heating system adoption by Norwegian households is taken up as a case study. An interdisciplinary approach, applying various established theories including those of psychology, is applied to create a model for consumer behavior and implement this behavior in an Agent-Based Model (ABM) to simulate heating technology diffusion. A mail-survey, carried out in autumn 2008, is a means to collect information for parameterizing the agent-based model, for gaining empirical facts, and for validating the developed model at micro-level. Survey sample consisted of 1500 Norwegian households drawn from population register and 1500 wood pellet users in Norway. The response rates were 10.3% and 34.6% for population sample and wood pellet sample respectively. This study is divided into two parts; empirical analysis and agent-based simulation. The empirical analysis aims at fully understanding the important aspects of adoption decision and their implications, in order to assist simulation. The analysis particularly contributes to the identification of differences/similarities between adopters and non adopters of wood pellet heating with respects to some key points of adoption derived from different theories, psychological factors underlying the adoption-decision of wood pellet heating, and the rationales underlying Norwegian households' decisions regarding their future heating system. The simulation study aims at exploring the mechanism of heterogeneous household decision-making giving rise to the diffusion of heating systems, and

  11. Role of coating agent in iron oxide nanoparticle formation in an aqueous dispersion: Experiments and simulation.

    Science.gov (United States)

    Bachhar, Nirmalya; Bandyopadhyaya, Rajdip

    2016-02-15

    Iron oxide (Fe3O4) nanoparticle was synthesized by coprecipitation and was modeled and solved using a hybrid (discrete-continuous) model, based on a kinetic Monte Carlo (kMC) simulation scheme. The latter was combined with the constant number MC method, to improve both speed and accuracy of the simulation. Complete particle size distribution (PSD) from simulation matches very well with PSD of both uncoated and coated (with either polyacrylic acid or dextran) Fe3O4 nanoparticles, obtained from our experiments. The model is general, as the time scales of various processes (nucleation, diffusion-growth and coagulation-growth) are incorporated in rate equations, while, input simulation parameters are experimentally measured quantities. With the help of the validated model, effect of coating agent on coagulation-growth was estimated by a single, fitted, coagulation-efficiency parameter. Our simulation shows that, logarithm of coagulation-efficiency scales linearly with logarithm of inverse of the molecular weight of the coating agent. With this scaling law, our model is able to a priori predict the experimental PSD of Fe3O4 nanoparticles, synthesized with an even higher molecular weight of dextran. PMID:26624531

  12. On Mechanism, Process and Polity: An Agent-Based Modeling and Simulation Approach

    Directory of Open Access Journals (Sweden)

    Camelia Florela Voinea

    2014-07-01

    Full Text Available The present approach provides a theoretical account of political culture-based modeling of political change phenomena. Our approach is an agent-based simulation model inspired by a social-psychological account of the relation between the individual agents (citizens and the polity. It includes political culture as a fundamental modeling dimension. On this background, we reconsider the operational definitions of agent, mechanism, process, and polity so as to specify the role they play in the modeling of political change phenomena. We evaluate our previous experimental simulation experience in corruption emergence and political attitude change. The paper approaches the artificial polity as a political culture-based model of a body politic. It involves political culture concepts to account for the complexity of domestic political phenomena, going from political attitude change at the individual level up to major political change at the societal level. Architecture, structure, unit of interaction, generative mechanisms and processes are described. Both conceptual and experimental issues are described so as to highlight the differences between the simulation models of society and polity.

  13. Little by little does the trick design and construction of a discrete event agent-based simulation framework

    OpenAIRE

    Matsopoulos, Alexandros

    2007-01-01

    Simulation is one of the most widely used techniques in operations research. In the military context, agent-based simulations have been extensively used by defense agencies worldwide. Despite the numerous disadvantages and limitations associated with timestepping, most of the combat-oriented agent-based simulation models are time-step implementations. The Discrete Event Scheduling (DES) paradigm, on the other hand, is free of these disadvantages and limitations. The scope of this thesis...

  14. Wetlands Spatial-Temporal Distribution Multi-Scale Simulation Using Multi-Agent System

    Directory of Open Access Journals (Sweden)

    Huan Yu

    2012-08-01

    Full Text Available The simulation of wetland landscape spatial-temporal distribution not only can reveal the mechanisms and laws of landscape evolution, but achieve the sustainable land use as well as provide supports for wetland conservation and management. In this report, the inland freshwater wetlands in the Sanjiang Plain of China were selected for wetland landscape changing process simulation studies. Results showed that both visual effects of simulation and prediction were good and the total accuracy co-efficiency of points to points was also significantly high (above 82%, which demonstrated the feasibility and effectiveness of wetland landscape spatial-temporal distribution simulation using Multi-Agent System (MAS. Scales exerted influence on visual effects, simulation accuracies and statistics of landscape index. Scale effects were obvious during simulation process using MAS. It was demonstrated that 60m was the best scale for simulation. It was shown that contagion index lines were exponential distribution while accuracy lines were lognormal distribution with the scale rising, which provided a reference for scale effect assessment and simulation scale selection.

  15. Introduction to the Finite-Difference Time-Domain (FDTD) Method for Electromagnetics

    CERN Document Server

    Gedney, Stephen

    2011-01-01

    Introduction to the Finite-Difference Time-Domain (FDTD) Method for Electromagnetics provides a comprehensive tutorial of the most widely used method for solving Maxwell's equations -- the Finite Difference Time-Domain Method. This book is an essential guide for students, researchers, and professional engineers who want to gain a fundamental knowledge of the FDTD method. It can accompany an undergraduate or entry-level graduate course or be used for self-study. The book provides all the background required to either research or apply the FDTD method for the solution of Maxwell's equations to p

  16. High-separation efficiency micro-fabricated multi-capillary gas chromatographic columns for simulants of the nerve agents and blister agents

    OpenAIRE

    Li, Yi; Du, Xiaosong; Wang, Yang; Tai, Huiling; Qiu, Dong; Lin, Qinghao; Jiang, Yadong

    2014-01-01

    To achieve both high speed and separation efficiency in the separation of a mixture of nerve and blister agent simulants, a high-aspect-ratio micro-fabricated multi-capillary column (MCC, a 50-cm-long, 450-μm-deep, and 60-μm-wide four-capillary column) was fabricated by the application of the microelectromechanical system (MEMS) techniques. Mixtures of chemical warfare agent (CWA) simulants - dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), and methyl salicylate - were used as sam...

  17. Security Analysis of Selected AMI Failure Scenarios Using Agent Based Game Theoretic Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Abercrombie, Robert K [ORNL; Schlicher, Bob G [ORNL; Sheldon, Frederick T [ORNL

    2014-01-01

    Information security analysis can be performed using game theory implemented in dynamic Agent Based Game Theoretic (ABGT) simulations. Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. We concentrated our analysis on the Advanced Metering Infrastructure (AMI) functional domain which the National Electric Sector Cyber security Organization Resource (NESCOR) working group has currently documented 29 failure scenarios. The strategy for the game was developed by analyzing five electric sector representative failure scenarios contained in the AMI functional domain. From these five selected scenarios, we characterize them into three specific threat categories affecting confidentiality, integrity and availability (CIA). The analysis using our ABGT simulation demonstrates how to model the AMI functional domain using a set of rationalized game theoretic rules decomposed from the failure scenarios in terms of how those scenarios might impact the AMI network with respect to CIA.

  18. Agent-based simulation of pedestrian behaviour in closed spaces: a museum case study

    CERN Document Server

    Pluchino, Alessandro; Inturri, Giuseppe; Rapisarda, Andrea; Ignaccolo, Matteo

    2013-01-01

    In order to analyse the behaviour of pedestrians at the very fine scale, while moving along the streets, in open spaces or inside a building, simulation modelling becomes an essential tool. In these spatial environments, in the presence of unusual demand flows, simulation requires the ability to model the local dynamics of individual decision making and behaviour, which is strongly affected by the geometry, randomness, social preferences, local and collective behaviour of other individuals. The dynamics of people visiting and evacuating a museum offers an excellent case study along this line. In this paper we realize an agent-based simulation of the Castello Ursino museum in Catania (Italy), evaluating its carrying capacity in terms of both satisfaction of the visitors in regime of normal fruition and their safety under alarm conditions.

  19. Multi-agent simulation of competitive electricity markets: Autonomous systems cooperation for European market modeling

    DEFF Research Database (Denmark)

    Santos, Gabriel; Pinto, Tiago; Morais, Hugo;

    2015-01-01

    provides the means for the exemplification of the usefulness of this ontology. A case study using the proposed multi-agent platform is presented, considering a scenario based on real data that simulates the European Electricity Market environment, and comparing its performance using different market...... mechanisms. The main goal is to demonstrate the advantages that the integration of various market models and simulation platforms have for the study of the electricity markets’ evolution.......The electricity market restructuring, and its worldwide evolution into regional and even continental scales, along with the increasing necessity for an adequate integration of renewable energy sources, is resulting in a rising complexity in power systems operation. Several power system simulators...

  20. Model reduction for agent-based social simulation: Coarse-graining a civil violence model

    Science.gov (United States)

    Zou, Yu; Fonoberov, Vladimir A.; Fonoberova, Maria; Mezic, Igor; Kevrekidis, Ioannis G.

    2012-06-01

    Agent-based modeling (ABM) constitutes a powerful computational tool for the exploration of phenomena involving emergent dynamic behavior in the social sciences. This paper demonstrates a computer-assisted approach that bridges the significant gap between the single-agent microscopic level and the macroscopic (coarse-grained population) level, where fundamental questions must be rationally answered and policies guiding the emergent dynamics devised. Our approach will be illustrated through an agent-based model of civil violence. This spatiotemporally varying ABM incorporates interactions between a heterogeneous population of citizens [active (insurgent), inactive, or jailed] and a population of police officers. Detailed simulations exhibit an equilibrium punctuated by periods of social upheavals. We show how to effectively reduce the agent-based dynamics to a stochastic model with only two coarse-grained degrees of freedom: the number of jailed citizens and the number of active ones. The coarse-grained model captures the ABM dynamics while drastically reducing the computation time (by a factor of approximately 20).

  1. Parallel Agent-Based Simulations on Clusters of GPUs and Multi-Core Processors

    Energy Technology Data Exchange (ETDEWEB)

    Aaby, Brandon G [ORNL; Perumalla, Kalyan S [ORNL; Seal, Sudip K [ORNL

    2010-01-01

    An effective latency-hiding mechanism is presented in the parallelization of agent-based model simulations (ABMS) with millions of agents. The mechanism is designed to accommodate the hierarchical organization as well as heterogeneity of current state-of-the-art parallel computing platforms. We use it to explore the computation vs. communication trade-off continuum available with the deep computational and memory hierarchies of extant platforms and present a novel analytical model of the tradeoff. We describe our implementation and report preliminary performance results on two distinct parallel platforms suitable for ABMS: CUDA threads on multiple, networked graphical processing units (GPUs), and pthreads on multi-core processors. Message Passing Interface (MPI) is used for inter-GPU as well as inter-socket communication on a cluster of multiple GPUs and multi-core processors. Results indicate the benefits of our latency-hiding scheme, delivering as much as over 100-fold improvement in runtime for certain benchmark ABMS application scenarios with several million agents. This speed improvement is obtained on our system that is already two to three orders of magnitude faster on one GPU than an equivalent CPU-based execution in a popular simulator in Java. Thus, the overall execution of our current work is over four orders of magnitude faster when executed on multiple GPUs.

  2. Simulating GenCo bidding strategies in electricity markets with an agent-based model

    International Nuclear Information System (INIS)

    In this paper we use an agent-based simulation model, EMCAS, to analyze market power in electricity markets. We focus on the effect of congestion management on the ability of generating companies (GenCos) to raise prices beyond competitive levels. An 11-node test power system is used to compare a market design based on locational marginal pricing with a market design that uses system marginal pricing and congestion management by counter trading. Bidding strategies based on both physical and economic withholding are compared to a base case with production cost bidding. The results show that unilateral market power is exercised under both pricing mechanisms. However, the largest changes in consumer costs and GenCo profits due to strategic bidding occur under the locational marginal pricing scheme. The analysis also illustrates that agent-based modeling can contribute important insights into the complex interactions between the participants in transmission-constrained electricity markets. (Author)

  3. Modelling Multi-agent in Emission Market based on Experimental Economics Simulations

    DEFF Research Database (Denmark)

    Chao, Jiang; Xue, Yusheng; Jie, Huang; Wu, Qiuwei; Yang, Guangya

    2014-01-01

    influencing rules on human partic ipants’ uncertain behaviors are extracted, which can aid the construction of multi-agent stochastic models with the same distribution characteristics. In this way, only a small group of humans are needed to represent the special decision makers, who can inte ract with large...... numbers of multi-agents constructed by the aforementioned method. The methodology discussed in this paper can overcome the scale limitations and meanwhile maintain the merits of experimental economics....... the multi-scenario experiments is also limited due to the variations of human participants ’ concentration level. This paper adopts a hybrid interactive simulation methodology. Human-subjected experime nts with a small group of human participants are conducted, major driving factors and their...

  4. Graceful Failure and Societal Resilience Analysis Via Agent-Based Modeling and Simulation

    Science.gov (United States)

    Schopf, P. S.; Cioffi-Revilla, C.; Rogers, J. D.; Bassett, J.; Hailegiorgis, A. B.

    2014-12-01

    Agent-based social modeling is opening up new methodologies for the study of societal response to weather and climate hazards, and providing measures of resiliency that can be studied in many contexts, particularly in coupled human and natural-technological systems (CHANTS). Since CHANTS are complex adaptive systems, societal resiliency may or may not occur, depending on dynamics that lack closed form solutions. Agent-based modeling has been shown to provide a viable theoretical and methodological approach for analyzing and understanding disasters and societal resiliency in CHANTS. Our approach advances the science of societal resilience through computational modeling and simulation methods that complement earlier statistical and mathematical approaches. We present three case studies of social dynamics modeling that demonstrate the use of these agent based models. In Central Asia, we exmaine mutltiple ensemble simulations with varying climate statistics to see how droughts and zuds affect populations, transmission of wealth across generations, and the overall structure of the social system. In Eastern Africa, we explore how successive episodes of drought events affect the adaptive capacity of rural households. Human displacement, mainly, rural to urban migration, and livelihood transition particularly from pastoral to farming are observed as rural households interacting dynamically with the biophysical environment and continually adjust their behavior to accommodate changes in climate. In the far north case we demonstrate one of the first successful attempts to model the complete climate-permafrost-infrastructure-societal interaction network as a complex adaptive system/CHANTS implemented as a ``federated'' agent-based model using evolutionary computation. Analysis of population changes resulting from extreme weather across these and other cases provides evidence for the emergence of new steady states and shifting patterns of resilience.

  5. Explicit formulation of second and third order optical nonlinearity in the FDTD framework

    CERN Document Server

    Varin, Charles; Bart, Graeme; Fennel, Thomas; Brabec, Thomas

    2016-01-01

    The finite-difference time-domain (FDTD) method is a flexible and powerful technique for rigorously solving Maxwell's equations. However, three-dimensional optical nonlinearity in current commercial and research FDTD softwares requires solving iteratively an implicit form of Maxwell's equations over the entire numerical space and at each time step. Reaching numerical convergence demands significant computational resources and practical implementation often implies a complete rewriting of the core FDTD engine. In this paper, we present an explicit method to include second and third order optical nonlinearity in the FDTD framework based on a nonlinear generalization of the Lorentz dispersion model derived from an analytical solution of the quantum mechanical two-level equations. With the proposed approach, numerical integration is simple, intuitive, fully explicit, and computationally efficient.

  6. Unconditionally Stable Bilinear Transformation FDTD Algorithm for Modeling Double-Negative Meta-material Electromagnetic Problems

    Science.gov (United States)

    Ramadan, Omar Salameh

    2010-03-01

    Accurate and unconditionally stable finite difference time domain (FDTD) algorithm is presented for modeling electromagnetic wave propagation in double-negative (DNG) meta-material domains. The proposed algorithm is based on incorporating the Bilinear transformation technique into the FDTD implementations of Maxwell’s equations. The stability of the proposed approach is studied by combining the von Neumann method with the Routh-Huwitz criterion and it has been observed that the proposed algorithm is free from the Courant-Friedrichs-Lewy (CFL) stability limit of the conventional FDTD scheme. Furthermore, the proposed algorithm is incorporated with the split-step FDTD scheme to model two-dimensional problems. Numerical examples carried out in one and two dimensional domains are included to show the validity of the proposed algorithm.

  7. Conditions Facilitating the Aversion of Unpopular Norms: An Agent-Based Simulation Study

    Directory of Open Access Journals (Sweden)

    Zoofishan Zareen

    2016-07-01

    Full Text Available People mostly facilitate and manage their social lives adhering to the prevalent norms. There are some norms which are unpopular, yet people adhere to them. Ironically, people at individual level do not agree to these norms, but, they still follow and even facilitate them. Irrespective of the social and psychological reasons behind their persistence, sometimes, for societal good, it is necessary to oppose and possibly avert the unpopular norms. In this paper, we model theorydriven computational specifications of Emperor’s Dilemma into an agent-based simulation, to understand the the conditions that result in emergence of unpopular norms. The reciprocal nature of persistence and aversion of norms, thus, is utilized to define situations under which these norms can be changed and averted. Simulation is performed under many interesting “what-if” questions. The simulation results reveal that under high density conditions of agent population with a high percentage of norm aversion activists, the aversion of unpopular norms can be achieved.

  8. Agent-based model of angiogenesis simulates capillary sprout initiation in multicellular networks.

    Science.gov (United States)

    Walpole, J; Chappell, J C; Cluceru, J G; Mac Gabhann, F; Bautch, V L; Peirce, S M

    2015-09-01

    Many biological processes are controlled by both deterministic and stochastic influences. However, efforts to model these systems often rely on either purely stochastic or purely rule-based methods. To better understand the balance between stochasticity and determinism in biological processes a computational approach that incorporates both influences may afford additional insight into underlying biological mechanisms that give rise to emergent system properties. We apply a combined approach to the simulation and study of angiogenesis, the growth of new blood vessels from existing networks. This complex multicellular process begins with selection of an initiating endothelial cell, or tip cell, which sprouts from the parent vessels in response to stimulation by exogenous cues. We have constructed an agent-based model of sprouting angiogenesis to evaluate endothelial cell sprout initiation frequency and location, and we have experimentally validated it using high-resolution time-lapse confocal microscopy. ABM simulations were then compared to a Monte Carlo model, revealing that purely stochastic simulations could not generate sprout locations as accurately as the rule-informed agent-based model. These findings support the use of rule-based approaches for modeling the complex mechanisms underlying sprouting angiogenesis over purely stochastic methods. PMID:26158406

  9. GMES: A Python package for solving Maxwell’s equations using the FDTD method

    Science.gov (United States)

    Chun, Kyungwon; Kim, Huioon; Kim, Hyounggyu; Jung, Kil Su; Chung, Youngjoo

    2013-04-01

    This paper describes GMES, a free Python package for solving Maxwell’s equations using the finite-difference time-domain (FDTD) method. The design of GMES follows the object-oriented programming (OOP) approach and adopts a unique design strategy where the voxels in the computational domain are grouped and then updated according to its material type. This piecewise updating scheme ensures that GMES can adopt OOP without losing its simple structure and time-stepping speed. The users can easily add various material types, sources, and boundary conditions into their code using the Python programming language. The key design features, along with the supported material types, excitation sources, boundary conditions and parallel calculations employed in GMES are also described in detail. Catalog identifier: AEOK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOK_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License v3.0 No. of lines in distributed program, including test data, etc.: 17700 No. of bytes in distributed program, including test data, etc.: 89878 Distribution format: tar.gz Programming language: C++, Python. Computer: Any computer with a Unix-like system with a C++ compiler, and a Python interpreter; developed on 2.53 GHz Intel CoreTM i3. Operating system: Any Unix-like system; developed under Ubuntu 12.04 LTS 64 bit. Has the code been vectorized or parallelized?: Yes. Parallelized with MPI directives (optional). RAM: Problem dependent (a simulation with real valued electromagnetic field uses roughly 0.18 KB per Yee cell.) Classification: 10. External routines: SWIG [1], Cython [2], NumPy [3], SciPy [4], matplotlib [5], MPI for Python [6] Nature of problem: Classical electrodynamics Solution method: Finite-difference time-domain (FDTD) method Additional comments: This article describes version 0.9.5. The most recent version can be downloaded at the GMES

  10. An algorithm for the treatment of curved metallic laminas in the FDTD method

    OpenAIRE

    Railton, CJ

    1993-01-01

    The Finite Difference Time Domain (FDTD) method, implemented in Cartesian coordinates, is well proven as an efficient technique for the electromagnetic analysis of a wide variety of microwave structures. The standard FDTD method is, however, less efficient if the structure under investigation has boundaries which are not parallel to the coordinate axes. Techniques designed to overcome this problem such as locally or globally deformed grids, or the use of nonorthogonal coordinate systems have ...

  11. Catching the PHEVer: Simulating Electric Vehicle Diffusion with an Agent-Based Mixed Logit Model of Vehicle Choice

    OpenAIRE

    Maxwell Brown

    2013-01-01

    This research develops then merges two separate models to simulate electric vehicle diffusion through recreation of the Boston metropolitan statistical area vehicle market place. The first model is a mixed (random parameters) logistic regression applied to data from the US Department of Transportation's 2009 National Household Travel Survey. The second, agent-based model simulates social network interactions through which agents' vehicle choice sets are endogenously determined. Parameters fro...

  12. Scanning surface-enhanced Raman spectroscopy (SERS) of chemical agent simulants on templated Au-Ag nanowire substrates

    Science.gov (United States)

    Hoffmann, J. A.; Miragliotta, J. A.; Wang, J.; Tyagi, P.; Maddanimath, T.; Gracias, D. H.; Papadakis, S. J.

    2009-05-01

    We report the results of scanning micro-Raman spectroscopy obtained on Au-Ag nanowires for a variety of chemical warfare agent simulants. Rough silver segments embedded in gold nanowires showed enhancement of 105 - 107 and allowed unique identification of 3 of 4 chemical agent simulants tested. These results suggest a promising method for detection of compounds significant for security applications, leading to sensors that are compact and selective.

  13. A Call to Arms: Standards for Agent-Based Modeling and Simulation

    OpenAIRE

    Andrew Collins; Mikel Petty; Daniele Vernon-Bido; Solomon Sherfey

    2015-01-01

    Standards are as old as civilization itself and they are vital to human development. Standards touch almost every part of our lives, from the water we drink to the language used to write this article. A sign of a good standard is one that we do not notice. Good standards exist and so do processes and organizations to create and maintain them. As agent-based modeling and simulation matures as a methodology, a discussion of standards applicable to it becomes increasingly important. Descriptive ...

  14. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Jensen, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    Concentration of MRI contrast agents (CA) is commonly determined indirectly using their relaxation effect. In quantitative perfusion studies, the change in the relaxation following a bolus passage is converted into concentrations assuming identical relaxivities for tissue and blood. Simulations...... presented in this study demonstrate that the relaxivity of blood pool CA depends significantly on both the host tissue and the pulse sequence, in agreement with previous experiments. In particular, the relaxation effect of Gd-based CA in brain tissues is several-fold larger than in bulk blood. The results...... can be applied to quantitation of perfusion, functional MRI and vessel size imaging...

  15. Development of the infrastructure for a multi-agent traffic management system simulation

    OpenAIRE

    Adova, Eleonora Vasileva

    2015-01-01

    This document contains detailed description of the design and the implementation of a multi-agent application controlling traffic lights in a city together with a system for simulating traffic and testing. The goal of this thesis is to design and build a simplified intelligent and distributed solution to the problem with the traffic in the big cities following different good practices in order to allow future refining of the model of the real world. The problem of the traffic in the big ci...

  16. Using an Agent-Based Modeling Simulation and Game to Teach Socio-Scientific Topics

    Directory of Open Access Journals (Sweden)

    Lori L. Scarlatos

    2014-02-01

    Full Text Available In our modern world, where science, technology and society are tightly interwoven, it is essential that all students be able to evaluate scientific evidence and make informed decisions. Energy Choices, an agent-based simulation with a multiplayer game interface, was developed as a learning tool that models the interdependencies between the energy choices that are made, growth in local economies, and climate change on a global scale. This paper presents the results of pilot testing Energy Choices in two different settings, using two different modes of delivery.

  17. Agent-Based Smart Grid Market Simulation with Connection to Real Infrastructures

    DEFF Research Database (Denmark)

    Santos, Gabriel; Pinto, Tiago; Gomes, Luis;

    2015-01-01

    The consensus behind Smart Grids (SG) as one of the most promising solutions for the massive integration of renewable energy sources in power systems has led to the practical implementation of several prototypes and pilots that aim at testing and validating SG methodologies. The urgent need...... to accommodate such resources of distributed and intermittent nature and the impact that a deficient management of energy sources has on the global population require that alternative solutions are experimented. This paper presents a multi-agent based SG simulation platform that is connected to physical...

  18. Participatory Agent-Based Simulation for Renewable Resource Management: The Role of the Cormas Simulation Platform to Nurture a Community of Practice

    OpenAIRE

    Christophe Le Page; Nicolas Becu; Pierre Bommel; François Bousquet

    2012-01-01

    This paper describes how the Cormas platform has been used for 12 years as an artefact to foster learning about agent-based simulation for renewable resource management. Among the existing generic agent-based simulation platforms, Cormas occupies a tiny, yet lively, place. Thanks to regular training sessions and an electronic forum, a community of users has been gradually established that has enabled a sharing of ideas, practices and knowledge, and the emergence of a genuine community of prac...

  19. Multi-Agent-Based Simulation of a Complex Ecosystem of Mental Health Care.

    Science.gov (United States)

    Kalton, Alan; Falconer, Erin; Docherty, John; Alevras, Dimitris; Brann, David; Johnson, Kyle

    2016-02-01

    This paper discusses the creation of an Agent-Based Simulation that modeled the introduction of care coordination capabilities into a complex system of care for patients with Serious and Persistent Mental Illness. The model describes the engagement between patients and the medical, social and criminal justice services they interact with in a complex ecosystem of care. We outline the challenges involved in developing the model, including process mapping and the collection and synthesis of data to support parametric estimates, and describe the controls built into the model to support analysis of potential changes to the system. We also describe the approach taken to calibrate the model to an observable level of system performance. Preliminary results from application of the simulation are provided to demonstrate how it can provide insights into potential improvements deriving from introduction of care coordination technology. PMID:26590977

  20. Simulation of game analysis based on an agent-based artificial stock market re-examined

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This work re-examined the simulation result of game analysis (Joshi et al., 2000) based on an agent-based model,Santa Fe Institute Artificial Stock Market. Allowing for recent research work on this artificial model, this paper's modified game simulations found that the dividend amplitude parameter is a crucial factor and that the original conclusion still holds in a not long period, but only when the dividend amplitude is large enough. Our explanation of this result is that the dividend amplitude parameter is a measurement of market uncertainty. The greater the uncertainty, the greater the price volatility, and so is the risk of investing in the stock market. The greater the risk, the greater the advantage of including technical rules.

  1. Promoting Conceptual Change for Complex Systems Understanding: Outcomes of an Agent-Based Participatory Simulation

    Science.gov (United States)

    Rates, Christopher A.; Mulvey, Bridget K.; Feldon, David F.

    2016-03-01

    Components of complex systems apply across multiple subject areas, and teaching these components may help students build unifying conceptual links. Students, however, often have difficulty learning these components, and limited research exists to understand what types of interventions may best help improve understanding. We investigated 32 high school students' understandings of complex systems components and whether an agent-based simulation could improve their understandings. Pretest and posttest essays were coded for changes in six components to determine whether students showed more expert thinking about the complex system of the Chesapeake Bay watershed. Results showed significant improvement for the components Emergence (r = .26, p = .03), Order (r = .37, p = .002), and Tradeoffs (r = .44, p = .001). Implications include that the experiential nature of the simulation has the potential to support conceptual change for some complex systems components, presenting a promising option for complex systems instruction.

  2. Promoting Conceptual Change for Complex Systems Understanding: Outcomes of an Agent-Based Participatory Simulation

    Science.gov (United States)

    Rates, Christopher A.; Mulvey, Bridget K.; Feldon, David F.

    2016-08-01

    Components of complex systems apply across multiple subject areas, and teaching these components may help students build unifying conceptual links. Students, however, often have difficulty learning these components, and limited research exists to understand what types of interventions may best help improve understanding. We investigated 32 high school students' understandings of complex systems components and whether an agent-based simulation could improve their understandings. Pretest and posttest essays were coded for changes in six components to determine whether students showed more expert thinking about the complex system of the Chesapeake Bay watershed. Results showed significant improvement for the components Emergence ( r = .26, p = .03), Order ( r = .37, p = .002), and Tradeoffs ( r = .44, p = .001). Implications include that the experiential nature of the simulation has the potential to support conceptual change for some complex systems components, presenting a promising option for complex systems instruction.

  3. Use of virtual simulator for agent training in radiation protection actions in major events

    International Nuclear Information System (INIS)

    With the proximity of the events of the Olympic Games, Brazil can become a great place of visibility for running dirty bombs or any other radiation mode proliferation by terrorists. Aware of these problems, the government and the organizations created managements of emergencies to ensure that these events elapse in an orderly and safe manner. The management of emergency situations at an event is a complex problem, which involves dynamic, unforeseen and unintended situations, emphasizing the potential complexity of the contexts in which organizations operate and, as a consequence, the people involved in the execution of multiple tasks from activities that require intense cognitive effort, are often challenged to adapt dynamically to maintain the productivity of the organization at satisfactory levels of performance usually impedes these people reflect on the results of their actions and learn from them. Therefore, it is extremely important to create tools that address the methods and techniques of Cognitive Task Analysis (CTA) to assist in the previous training of the security agents, for example, detection and approaches of people who carry radioactive elements. One of the possible ways to accomplish this training is through the use of virtual reality. Virtual environments bring some advantages like reducing costs and risks. The aim of this paper is to present a virtual simulator to evaluate the use in training agents in major events. As a case study, the Maracana and the agents of the National Nuclear Energy Commission (CNEN) was chosen. (author)

  4. Modeling and simulation of virtual human's coordination based on multi-agent systems

    Science.gov (United States)

    Zhang, Mei; Wen, Jing-Hua; Zhang, Zu-Xuan; Zhang, Jian-Qing

    2006-10-01

    The difficulties and hotspots researched in current virtual geographic environment (VGE) are sharing space and multiusers operation, distributed coordination and group decision-making. The theories and technologies of MAS provide a brand-new environment for analysis, design and realization of distributed opening system. This paper takes cooperation among virtual human in VGE which multi-user participate in as main researched object. First we describe theory foundation truss of VGE, and present the formalization description of Multi-Agent System (MAS). Then we detailed analyze and research arithmetic of collectivity operating behavior learning of virtual human based on best held Genetic Algorithm(GA), and establish dynamics action model which Multi-Agents and object interact dynamically and colony movement strategy. Finally we design a example which shows how 3 evolutional Agents cooperate to complete the task of colony pushing column box, and design a virtual world prototype of virtual human pushing box collectively based on V-Realm Builder 2.0, moreover we make modeling and dynamic simulation with Simulink 6.

  5. Use of virtual simulator for agent training in radiation protection actions in major events

    Energy Technology Data Exchange (ETDEWEB)

    Passos, Claudio Azevedo, E-mail: cpassos.cp2@gmail.com [Universidade Federal do Rio de Janeiro (CCMN/NCE/UFRJ), Rio de Janeiro, RJ (Brazil); Mol, Antonio Carlos A.; Carvalho, Paulo V.R., E-mail: mol@ien.gov.br, E-mail: paulov@ien.gov.br [nstituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lima, Fabio Almeida; Rocha, Tiago Lima, E-mail: profantoniocarlosmol@gmail.com, E-mail: falmeida@unicarioca.edu.br, E-mail: tlrtiago@gmail.com [Centro Universitario Carioca (Unicarioca), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    With the proximity of the events of the Olympic Games, Brazil can become a great place of visibility for running dirty bombs or any other radiation mode proliferation by terrorists. Aware of these problems, the government and the organizations created managements of emergencies to ensure that these events elapse in an orderly and safe manner. The management of emergency situations at an event is a complex problem, which involves dynamic, unforeseen and unintended situations, emphasizing the potential complexity of the contexts in which organizations operate and, as a consequence, the people involved in the execution of multiple tasks from activities that require intense cognitive effort, are often challenged to adapt dynamically to maintain the productivity of the organization at satisfactory levels of performance usually impedes these people reflect on the results of their actions and learn from them. Therefore, it is extremely important to create tools that address the methods and techniques of Cognitive Task Analysis (CTA) to assist in the previous training of the security agents, for example, detection and approaches of people who carry radioactive elements. One of the possible ways to accomplish this training is through the use of virtual reality. Virtual environments bring some advantages like reducing costs and risks. The aim of this paper is to present a virtual simulator to evaluate the use in training agents in major events. As a case study, the Maracana and the agents of the National Nuclear Energy Commission (CNEN) was chosen. (author)

  6. From households to urban structures: space representations as engine of dynamics in multi-agent simulations

    Directory of Open Access Journals (Sweden)

    Jean-Luc Bonnefoy

    2003-01-01

    Full Text Available L'idée principale de ce texte est de simuler la construction d'une ségrégation urbaine via des représentations spatiales. Pour faire aboutir ce projet, le modèle doit être très simple parce que nous souhaitons plus simuler et comprendre les processus de production d'espace, leurs temporalités et leur influence dynamique sur l'apprentissage de l’espace par les individus, que reproduire une situation réelle. En outre, ce travail est inclus dans une recherche de l'UMR 6012, qui pratique une analyse spatiale centrée sur l’analyse des processus dans un contexte de faible quantification. Aussi, nous employons un système multi-agents pour mettre en oeuvre une hiérarchie enchevêtrée propre aux processus complexes caractéristiques des sciences sociales : une structure spatiale au niveau macro émergeant de règles simples établies au niveau micro et une rétro-action du niveau macro agissant à son tour sur le niveau micro. Le modèle est construit comme suit : des agents ménages parcourent l'univers multi-agents pour trouver le meilleur domicile selon des contraintes comme leurs revenus ou le prestige des lieux. Ils apprennent cet espace par la pratique et, consécutivement, construisent des représentations spatiales individuelles variées qui vont participer à la construction de représentations collectives de l'espace. Ces deux types de représentations contribueront à aider les agents ménages à trouver le meilleur choix résidentiel. Puis, ces choix modifieront les caractéristiques des espaces et les nouvelles structures spatiales contraindront les agents ménages dans leurs pratiques de cet espace, leurs représentations individuelles et leurs choix. Ces rétro-actions basées sur des représentations spatiales contribuent en grande partie à la construction d’une ségrégation urbaine.

  7. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz.

    Science.gov (United States)

    Zamorano, M; Torres-Silva, H

    2006-04-01

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) "inverse skin effect" shows up at 1800 MHz, with respect to a 900 MHz source. PMID:16552096

  8. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz

    International Nuclear Information System (INIS)

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source

  9. Modeling the Information Age Combat Model: An Agent-Based Simulation of Network Centric Operations

    Science.gov (United States)

    Deller, Sean; Rabadi, Ghaith A.; Bell, Michael I.; Bowling, Shannon R.; Tolk, Andreas

    2010-01-01

    The Information Age Combat Model (IACM) was introduced by Cares in 2005 to contribute to the development of an understanding of the influence of connectivity on force effectiveness that can eventually lead to quantitative prediction and guidelines for design and employment. The structure of the IACM makes it clear that the Perron-Frobenius Eigenvalue is a quantifiable metric with which to measure the organization of a networked force. The results of recent experiments presented in Deller, et aI., (2009) indicate that the value of the Perron-Frobenius Eigenvalue is a significant measurement of the performance of an Information Age combat force. This was accomplished through the innovative use of an agent-based simulation to model the IACM and represents an initial contribution towards a new generation of combat models that are net-centric instead of using the current platform-centric approach. This paper describes the intent, challenges, design, and initial results of this agent-based simulation model.

  10. An agent-based simulation model to study accountable care organizations.

    Science.gov (United States)

    Liu, Pai; Wu, Shinyi

    2016-03-01

    Creating accountable care organizations (ACOs) has been widely discussed as a strategy to control rapidly rising healthcare costs and improve quality of care; however, building an effective ACO is a complex process involving multiple stakeholders (payers, providers, patients) with their own interests. Also, implementation of an ACO is costly in terms of time and money. Immature design could cause safety hazards. Therefore, there is a need for analytical model-based decision-support tools that can predict the outcomes of different strategies to facilitate ACO design and implementation. In this study, an agent-based simulation model was developed to study ACOs that considers payers, healthcare providers, and patients as agents under the shared saving payment model of care for congestive heart failure (CHF), one of the most expensive causes of sometimes preventable hospitalizations. The agent-based simulation model has identified the critical determinants for the payment model design that can motivate provider behavior changes to achieve maximum financial and quality outcomes of an ACO. The results show nonlinear provider behavior change patterns corresponding to changes in payment model designs. The outcomes vary by providers with different quality or financial priorities, and are most sensitive to the cost-effectiveness of CHF interventions that an ACO implements. This study demonstrates an increasingly important method to construct a healthcare system analytics model that can help inform health policy and healthcare management decisions. The study also points out that the likely success of an ACO is interdependent with payment model design, provider characteristics, and cost and effectiveness of healthcare interventions. PMID:24715674

  11. Multi-agent simulations for emergency situations in an airport scenario

    Directory of Open Access Journals (Sweden)

    José Manuel MOLINA

    2013-06-01

    Full Text Available Normal 0 21 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} This paper presents a multi-agent framework using Net- Logo to simulate human and collective behaviors during emergency evacuations. Emergency situation appears when an unexpected event occurs. In indoor emergency situation, evacuation plans defined by facility manager explain procedure and safety ways to follow in an emergency situation. A critical and public scenario is an airport where there is an everyday transit of thousands of people. In this scenario the importance is related with incidents statistics regarding overcrowding and crushing in public buildings. Simulation has the objective of evaluating building layouts considering several possible configurations. Agents could be based on reactive behavior like avoid danger or follow other agent, or in deliberative behavior based on BDI model. This tool provides decision support in a real emergency scenario like an airport, analyzing alternative solutions to the evacuation process.

  12. Multi-agent simulations for emergency situations in an airport scenario

    Directory of Open Access Journals (Sweden)

    Ana Cristina BICHARRA

    2012-12-01

    Full Text Available Normal 0 21 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} This paper presents a multi-agent framework using Net- Logo to simulate human and collective behaviors during emergency evacuations. Emergency situation appears when an unexpected event occurs. In indoor emergency situation, evacuation plans defined by facility manager explain procedure and safety ways to follow in an emergency situation. A critical and public scenario is an airportwhere there is an everyday transit of thousands of people. In this scenario the importance is related with incidents statistics regarding overcrowding and crushing in public buildings. Simulation has the objective of evaluating building layouts considering several possible configurations. Agents could be based on reactive behavior like avoid danger or follow other agent, or in deliberative behavior based on BDI model. This tool provides decision support in a real emergency scenario like an airport, analyzing alternative solutions to the evacuation process.

  13. AGENT-BASED SIMULATION FOR KANSEI ENGINEERING: TESTING A FUZZY LINEAR QUANTIFICATION METHOD IN AN ARTIFICIAL WORLD

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper argues that agent-based simulation can be used as a way for testing Kansei Engineering methods which deal with the human reaction from sensory to mental state, that is, sensitivity, sense,sensibility, feeling, esthetics, emotion affection and intuition. A new fuzzy linear quantification method is tested in an artificial world by agent-based modeling and simulations, and the performance of the fuzzy linear method is compared with that of a genetic algorithm. The simulations can expand people's imagination and enhance people's intuition that the new fuzzy linear quantification method is effective.

  14. Evaluation of wholesale electric power market rules and financial risk management by agent-based simulations

    Science.gov (United States)

    Yu, Nanpeng

    As U.S. regional electricity markets continue to refine their market structures, designs and rules of operation in various ways, two critical issues are emerging. First, although much experience has been gained and costly and valuable lessons have been learned, there is still a lack of a systematic platform for evaluation of the impact of a new market design from both engineering and economic points of view. Second, the transition from a monopoly paradigm characterized by a guaranteed rate of return to a competitive market created various unfamiliar financial risks for various market participants, especially for the Investor Owned Utilities (IOUs) and Independent Power Producers (IPPs). This dissertation uses agent-based simulation methods to tackle the market rules evaluation and financial risk management problems. The California energy crisis in 2000-01 showed what could happen to an electricity market if it did not go through a comprehensive and rigorous testing before its implementation. Due to the complexity of the market structure, strategic interaction between the participants, and the underlying physics, it is difficult to fully evaluate the implications of potential changes to market rules. This dissertation presents a flexible and integrative method to assess market designs through agent-based simulations. Realistic simulation scenarios on a 225-bus system are constructed for evaluation of the proposed PJM-like market power mitigation rules of the California electricity market. Simulation results show that in the absence of market power mitigation, generation company (GenCo) agents facilitated by Q-learning are able to exploit the market flaws and make significantly higher profits relative to the competitive benchmark. The incorporation of PJM-like local market power mitigation rules is shown to be effective in suppressing the exercise of market power. The importance of financial risk management is exemplified by the recent financial crisis. In this

  15. Fire fighting trainers' exposure to carcinogenic agents in smoke diving simulators.

    Science.gov (United States)

    Laitinen, Juha; Mäkelä, Mauri; Mikkola, Jouni; Huttu, Ismo

    2010-01-15

    It is well known that fire fighters are potentially exposed to various carcinogenic agents at a fire scene. An almost unheeded issue, however, is fire fighters' exposure to carcinogenic agents in smoke diving simulators. Biomonitoring (urinary muconic acid, 1-naphthol and 1-pyrenol), dermal (polycyclic aromatic hydrocarbons) and occupational hygiene measurements (cyanides, hydrogen cyanide, polycyclic aromatic hydrocarbons, volatile organic compounds and formaldehyde) were used to determine how the burning material, the type of simulator and protective clothing used affect fire fighting trainers' exposure. The highest excretion of 1-pyrenol (sampled 6h after end of exposure, in average 4.3-9.2nmol/L) and emissions of benzene (1.0-2.5mg/m(3)) and hydrogen cyanide (0.2-0.9mg/m(3)) were measured during the burning of conifer plywood and chipboard, and the lowest when pure pine and spruce wood (1.5nmol/L, 0.6mg/m(3), and 0.05mg/m(3)) was burned. However the safest burning material seemed to be propane (1.0nmol/L, 0.2mg/m(3), and not measured). The type of simulator used affected trainers' exposure very clearly. The highest dermal whole body exposures to polycyclic aromatic hydrocarbons were measured in the fire house simulator (in average 1200ng/cm(2)). Clearly lower exposure levels were measured in container training sessions (760ng/cm(2)), where the average dermal exposure level was 35% lower than in the fire house. The exposure levels (30ng/cm(2)) in the gas simulator in turn, were only 4% of the levels in container training sessions. The amount of polycyclic aromatic hydrocarbons decreased by 80% on trainers' hands when they used under gloves (in average 8.7ng/cm(2)) compared to those (48.4ng/cm(2)) who did not. There was not difference in protection efficiency against polycyclic aromatic hydrocarbons between tested fire suits (Brage and Bristol). PMID:19576276

  16. Juxtaposition of system dynamics and agent-based simulation for a case study in immunosenescence.

    Directory of Open Access Journals (Sweden)

    Grazziela P Figueredo

    Full Text Available Advances in healthcare and in the quality of life significantly increase human life expectancy. With the aging of populations, new un-faced challenges are brought to science. The human body is naturally selected to be well-functioning until the age of reproduction to keep the species alive. However, as the lifespan extends, unseen problems due to the body deterioration emerge. There are several age-related diseases with no appropriate treatment; therefore, the complex aging phenomena needs further understanding. It is known that immunosenescence is highly correlated to the negative effects of aging. In this work we advocate the use of simulation as a tool to assist the understanding of immune aging phenomena. In particular, we are comparing system dynamics modelling and simulation (SDMS and agent-based modelling and simulation (ABMS for the case of age-related depletion of naive T cells in the organism. We address the following research questions: Which simulation approach is more suitable for this problem? Can these approaches be employed interchangeably? Is there any benefit of using one approach compared to the other? Results show that both simulation outcomes closely fit the observed data and existing mathematical model; and the likely contribution of each of the naive T cell repertoire maintenance method can therefore be estimated. The differences observed in the outcomes of both approaches are due to the probabilistic character of ABMS contrasted to SDMS. However, they do not interfere in the overall expected dynamics of the populations. In this case, therefore, they can be employed interchangeably, with SDMS being simpler to implement and taking less computational resources.

  17. Review of Parallel Agent-based Simulation%并行Agent仿真研究综述

    Institute of Scientific and Technical Information of China (English)

    余文广; 王维平; 李群

    2012-01-01

    As an effective approach to study complex systems, the method of Agent-based Modeling and Simulation (ABMS) is used widely in many research fields, but as the scale and complexity of its applications enlarge, the execution speed becomes an obstacle to implement ABMS. Parallel Agent-based Simulation (PABS) aims at reducing the execution time through executing concurrently the Agent models distributed on different process units, which is a direct approach to improve the execution speed. According to the principles of ABMS, the new characteristics of PABS that are different from Parallel Discrete Event Simulation were proposed. The overview about PABS was elaborated from the aspects of time synchronization algorithms, load balancing and communication optimizing. PABS based on general purpose graphics processing units was discussed. At last, some future research directions about PABS were proposed.%作为一种研究复杂系统的有效途径,基于Agent的建模仿真方法得到了广泛应用,但随着应用规模和复杂度的增加,仿真运行速度成为制约其应用的一个重要因素。并行Agent仿真通过将Agent模型分配到多个处理单元上同时运行来减少仿真运行时间,是提高仿真运行速度的一个直接手段。根据基于Agent的建模仿真的基本思想,分析了并行Agent仿真区别于传统的并行离散事件仿真的新特点,着重从时间同步协议、负载均衡、通信优化三方面阐述了并行Agent仿真的研究现状,并对基于通用目的图形处理器的并行Agent仿真进行了讨论。最后对并行Agent仿真未来的研究方向进行了展望。

  18. Preliminary simulation study of doppler reflectometry

    International Nuclear Information System (INIS)

    A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. (author)

  19. Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres.

    Science.gov (United States)

    Barat, Ana; Crane, Martin; Ruskin, Heather J

    2008-09-29

    Using poly(lactide-co-glycolide) (PLGA) particles for drug encapsulation and delivery has recently gained considerable popularity for a number of reasons. An advantage in one sense, but a drawback of PLGA use in another, is that drug delivery systems made of this material can provide a wide range of dissolution profiles, due to their internal structure and properties related to particles' manufacture. The advantages of enriching particulate drug design experimentation with computer models, are evident with simulations used to predict and optimize design, as well as indicate choice of best manufacturing parameters. In the present work, we seek to understand the phenomena observed for PLGA micro- and nanospheres, through Cellular Automata (CA) agent-based Monte Carlo (MC) models. Systems are studied both over large temporal scales (capturing slow erosion of PLGA) and for various spatial configurations (capturing initial as well as dynamic morphology). The major strength of this multi-agent approach is to observe dissolution directly, by monitoring the emergent behaviour: the dissolution profile manifested, as a sphere erodes. Different problematic aspects of the modelling process are discussed in details in this paper. The models were tested on experimental data from literature, demonstrating very good performance. Quantitative discussion is provided throughout the text in order to make a demonstration of the use in practice of the proposed model. PMID:18436414

  20. Development of Simulation System for the Disaster Evacuation Based on Multi-Agent Model Using GIS

    Institute of Scientific and Technical Information of China (English)

    Keisuke Uno; Kazuo Kashitama

    2008-01-01

    This paper presents a simulation system for the disaster evacuation based on multi-agent model considering geographical information. This system consists of three parts, the modeling for the land and buildings using GIS data, the analysis of disaster evacuation using multi-agent model, and the visualization for the numerical results using the virtual reality technique. By introducing the numerical solver of the natural disaster to the present system, it is possible to evaluate not only the damage of structure but also the dam- age of human being. Furthermore, it is possible to investigate the appropriate evacuation route by the simu- lation. The Dijkstra algorithm is used to obtain shortest route to the refuge. In addition, the visualization us- ing virtual reality technique is curried out to understand the feeling of refugee. The present system is applied to the evacuation analysis by the flood flow in urban area and is shown to be a useful tool to investigate the damage by natural disasters.

  1. Destruction of chemical agent simulants in a supercritical water oxidation bench-scale reactor

    International Nuclear Information System (INIS)

    A new design of supercritical water oxidation (SCWO) bench-scale reactor has been developed to handle high-risk wastes resulting from munitions demilitarization. The reactor consists of a concentric vertical double wall in which SCWO reaction takes place inside an inner tube (titanium grade 2, non-porous) whereas pressure resistance is ensured by a Hastelloy C-276 external vessel. The performances of this reactor were investigated with two different kinds of chemical warfare agent simulants: OPA (a mixture of isopropyl amine and isopropyl alcohol) as the binary precursor for nerve agent of sarin and thiodiglycol [TDG (HOC2H4)2S] as the model organic sulfur heteroatom. High destruction rates based on total organic carbon (TOC) were achieved (>99.99%) without production of chars or undesired gases such as carbon monoxide and methane. The carbon-containing product was carbon dioxide whereas the nitrogen-containing products were nitrogen and nitrous oxide. Sulfur was totally recovered in the aqueous effluent as sulfuric acid. No corrosion was noticed in the reactor after a cumulative operation time of more than 250 h. The titanium tube shielded successfully the pressure vessel from corrosion

  2. Detection and classification of organophosphate nerve agent simulants using support vector machines with multiarray sensors.

    Science.gov (United States)

    Sadik, Omowunmi; Land, Walker H; Wanekaya, Adam K; Uematsu, Michiko; Embrechts, Mark J; Wong, Lut; Leibensperger, Dale; Volykin, Alex

    2004-01-01

    The need for rapid and accurate detection systems is expanding and the utilization of cross-reactive sensor arrays to detect chemical warfare agents in conjunction with novel computational techniques may prove to be a potential solution to this challenge. We have investigated the detection, prediction, and classification of various organophosphate (OP) nerve agent simulants using sensor arrays with a novel learning scheme known as support vector machines (SVMs). The OPs tested include parathion, malathion, dichlorvos, trichlorfon, paraoxon, and diazinon. A new data reduction software program was written in MATLAB V. 6.1 to extract steady-state and kinetic data from the sensor arrays. The program also creates training sets by mixing and randomly sorting any combination of data categories into both positive and negative cases. The resulting signals were fed into SVM software for "pairwise" and "one" vs all classification. Experimental results for this new paradigm show a significant increase in classification accuracy when compared to artificial neural networks (ANNs). Three kernels, the S2000, the polynomial, and the Gaussian radial basis function (RBF), were tested and compared to the ANN. The following measures of performance were considered in the pairwise classification: receiver operating curve (ROC) Az indices, specificities, and positive predictive values (PPVs). The ROC Az) values, specifities, and PPVs increases ranged from 5% to 25%, 108% to 204%, and 13% to 54%, respectively, in all OP pairs studied when compared to the ANN baseline. Dichlorvos, trichlorfon, and paraoxon were perfectly predicted. Positive prediction for malathion was 95%. PMID:15032529

  3. Designing environmental campaigns by using agent-based simulations: strategies for changing environmental attitudes.

    Science.gov (United States)

    Mosler, Hans-Joachim; Martens, Thomas

    2008-09-01

    Agent-based computer simulation was used to create artificial communities in which each individual was constructed according to the principles of the elaboration likelihood model of Petty and Cacioppo [1986. The elaboration likelihood model of persuasion. In: Berkowitz, L. (Ed.), Advances in Experimental Social Psychology. Academic Press, New York, NY, pp. 123-205]. Campaigning strategies and community characteristics were varied systematically to understand and test their impact on attitudes towards environmental protection. The results show that strong arguments influence a green (environmentally concerned) population with many contacts most effectively, while peripheral cues have the greatest impact on a non-green population with fewer contacts. Overall, deeper information scrutiny increases the impact of strong arguments but is especially important for convincing green populations. Campaigns involving person-to-person communication are superior to mass-media campaigns because they can be adapted to recipients' characteristics. PMID:17548145

  4. Prediction Markets and Beliefs about Climate: Results from Agent-Based Simulations

    Science.gov (United States)

    Gilligan, J. M.; John, N. J.; van der Linden, M.

    2015-12-01

    Climate scientists have long been frustrated by persistent doubts a large portion of the public expresses toward the scientific consensus about anthropogenic global warming. The political and ideological polarization of this doubt led Vandenbergh, Raimi, and Gilligan [1] to propose that prediction markets for climate change might influence the opinions of those who mistrust the scientific community but do trust the power of markets.We have developed an agent-based simulation of a climate prediction market in which traders buy and sell future contracts that will pay off at some future year with a value that depends on the global average temperature at that time. The traders form a heterogeneous population with different ideological positions, different beliefs about anthropogenic global warming, and different degrees of risk aversion. We also vary characteristics of the market, including the topology of social networks among the traders, the number of traders, and the completeness of the market. Traders adjust their beliefs about climate according to the gains and losses they and other traders in their social network experience. This model predicts that if global temperature is predominantly driven by greenhouse gas concentrations, prediction markets will cause traders' beliefs to converge toward correctly accepting anthropogenic warming as real. This convergence is largely independent of the structure of the market and the characteristics of the population of traders. However, it may take considerable time for beliefs to converge. Conversely, if temperature does not depend on greenhouse gases, the model predicts that traders' beliefs will not converge. We will discuss the policy-relevance of these results and more generally, the use of agent-based market simulations for policy analysis regarding climate change, seasonal agricultural weather forecasts, and other applications.[1] MP Vandenbergh, KT Raimi, & JM Gilligan. UCLA Law Rev. 61, 1962 (2014).

  5. FDTD analysis of photonic quasicrystals with different tiling geometries and fabrication by single beam computer-generated holography

    CERN Document Server

    Zito, G; Santamato, E; Marino, A; Tkachenko, V; Abbate, G

    2013-01-01

    Multiple-beam holography has been widely used for the realization of photonic quasicrystals with high rotational symmetries not achievable by the conventional periodic crystals. Accurate control of the properties of the interfering beams is necessary to provide photonic band-gap structures. Here we show, by FDTD simulations of the transmission spectra of 8-fold quasiperiodic structures, how the geometric tiling of the structure affects the presence and properties of the photonic band-gap for low refractive index contrasts. Hence, we show an interesting approach to the fabrication of photonic quasicrystals based on the use of a programmable Spatial Light Modulator encoding Computer-Generated Holograms, that permits an accurate control of the writing pattern with almost no limitations in the pattern design. Using this single-beam technique we fabricated quasiperiodic structures with high rotational symmetries and different geometries of the tiling, demonstrating the great versatility of our technique.

  6. Recent Advances in Agent-Based Tsunami Evacuation Simulations: Case Studies in Indonesia, Thailand, Japan and Peru

    Science.gov (United States)

    Mas, Erick; Koshimura, Shunichi; Imamura, Fumihiko; Suppasri, Anawat; Muhari, Abdul; Adriano, Bruno

    2015-12-01

    As confirmed by the extreme tsunami events over the last decade (the 2004 Indian Ocean, 2010 Chile and 2011 Japan tsunami events), mitigation measures and effective evacuation planning are needed to reduce disaster risks. Modeling tsunami evacuations is an alternative means to analyze evacuation plans and possible scenarios of evacuees' behaviors. In this paper, practical applications of an agent-based tsunami evacuation model are presented to demonstrate the contributions that agent-based modeling has added to tsunami evacuation simulations and tsunami mitigation efforts. A brief review of previous agent-based evacuation models in the literature is given to highlight recent progress in agent-based methods. Finally, challenges are noted for bridging gaps between geoscience and social science within the agent-based approach for modeling tsunami evacuations.

  7. A Single-Machine Two-Agent Scheduling Problem by a Branch-and-Bound and Three Simulated Annealing Algorithms

    Directory of Open Access Journals (Sweden)

    Shangchia Liu

    2015-01-01

    Full Text Available In the field of distributed decision making, different agents share a common processing resource, and each agent wants to minimize a cost function depending on its jobs only. These issues arise in different application contexts, including real-time systems, integrated service networks, industrial districts, and telecommunication systems. Motivated by its importance on practical applications, we consider two-agent scheduling on a single machine where the objective is to minimize the total completion time of the jobs of the first agent with the restriction that an upper bound is allowed the total completion time of the jobs for the second agent. For solving the proposed problem, a branch-and-bound and three simulated annealing algorithms are developed for the optimal solution, respectively. In addition, the extensive computational experiments are also conducted to test the performance of the algorithms.

  8. Evaluating environmental strategies in a textile printing and dyeing enterprise by an agent-based simulation model

    Science.gov (United States)

    Gao, Lei; Ding, Yongsheng; Li, Fang

    2013-05-01

    To improve the capabilities of saving energy and reducing pollutant emission of textile printing and dyeing (PD) industry, this article presents a novel agent-based simulation model for assessing the impacts of environmental strategies on a PD enterprise. Two typical PD enterprises in China are simulated with different modelling granularities: one is at a module level, while the other is at an enterprise level. The module-level simulation model depicts detailed production processes in a PD enterprise and evaluates five candidate strategies on their capabilities of improving energy usage and waste emission. The enterprise-level simulation model views a PD enterprise as an agent and assesses three tax strategies for waste discharge. The simulation results show that the proposed general model could be a valuable tool to explore potential solutions to saving energy and reducing waste emission in PD enterprises, after being calibrated to a real case.

  9. An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group Formation

    Science.gov (United States)

    Maghami, Mahsa; Sukthankar, Gita

    In this paper, we introduce an agent-based simulation for investigating the impact of social factors on the formation and evolution of task-oriented groups. Task-oriented groups are created explicitly to perform a task, and all members derive benefits from task completion. However, even in cases when all group members act in a way that is locally optimal for task completion, social forces that have mild effects on choice of associates can have a measurable impact on task completion performance. In this paper, we show how our simulation can be used to model the impact of stereotypes on group formation. In our simulation, stereotypes are based on observable features, learned from prior experience, and only affect an agent's link formation preferences. Even without assuming stereotypes affect the agents' willingness or ability to complete tasks, the long-term modifications that stereotypes have on the agents' social network impair the agents' ability to form groups with sufficient diversity of skills, as compared to agents who form links randomly. An interesting finding is that this effect holds even in cases where stereotype preference and skill existence are completely uncorrelated.

  10. Comparing System Dynamics and Agent-Based Simulation for Tumour Growth and its Interactions with Effector Cells

    CERN Document Server

    Figueredo, Grazziela P

    2011-01-01

    There is little research concerning comparisons and combination of System Dynamics Simulation (SDS) and Agent Based Simulation (ABS). ABS is a paradigm used in many levels of abstraction, including those levels covered by SDS. We believe that the establishment of frameworks for the choice between these two simulation approaches would contribute to the simulation research. Hence, our work aims for the establishment of directions for the choice between SDS and ABS approaches for immune system-related problems. Previously, we compared the use of ABS and SDS for modelling agents' behaviour in an environment with nomovement or interactions between these agents. We concluded that for these types of agents it is preferable to use SDS, as it takes up less computational resources and produces the same results as those obtained by the ABS model. In order to move this research forward, our next research question is: if we introduce interactions between these agents will SDS still be the most appropriate paradigm to be u...

  11. Singularity Processing Method of Microstrip Line Edge Based on LOD-FDTD

    Directory of Open Access Journals (Sweden)

    Lei Li

    2014-01-01

    Full Text Available In order to improve the performance of the accuracy and efficiency for analyzing the microstrip structure, a singularity processing method is proposed theoretically and experimentally based on the fundamental locally one-dimensional finite difference time domain (LOD-FDTD with second-order temporal accuracy (denoted as FLOD2-FDTD. The proposed method can highly improve the performance of the FLOD2-FDTD even when the conductor is embedded into more than half of the cell by the coordinate transformation. The experimental results showed that the proposed method can achieve higher accuracy when the time step size is less than or equal to 5 times of that the Courant-Friedrich-Levy (CFL condition allowed. In comparison with the previously reported methods, the proposed method for calculating electromagnetic field near microstrip line edge not only improves the efficiency, but also can provide a higher accuracy.

  12. Unified matrix-exponential FDTD formulations for modeling electrically and magnetically dispersive materials

    Science.gov (United States)

    Ramadan, Omar

    2012-05-01

    Unified matrix-exponential finite difference time domain (ME-FDTD) formulations are presented for modeling linear multi-term electrically and magnetically dispersive materials. In the proposed formulations, Maxwell's curl equations and the related dispersive constitutive relations are cast into a set of first-order differential matrix system and the field's update equations can be extracted directly from the matrix-exponential approximation. The formulations have the advantage of simplicity as it allows modeling different linear dispersive materials in a systematic manner and also can be easily incorporated with the perfectly matched layer (PML) absorbing boundary conditions (ABCs) to model open region problems. Apart from its simplicity, it has been shown that the proposed formulations necessitate less storage requirements as compared with the well-know auxiliary differential equation FDTD (ADE-FDTD) scheme while maintaining the same accuracy performance.

  13. Comparing Simulation Output Accuracy of Discrete Event and Agent Based Models: A Quantitive Approach

    CERN Document Server

    Majid, Mazlina Abdul; Siebers, Peer-Olaf

    2010-01-01

    In our research we investigate the output accuracy of discrete event simulation models and agent based simulation models when studying human centric complex systems. In this paper we focus on human reactive behaviour as it is possible in both modelling approaches to implement human reactive behaviour in the model by using standard methods. As a case study we have chosen the retail sector, and here in particular the operations of the fitting room in the women wear department of a large UK department store. In our case study we looked at ways of determining the efficiency of implementing new management policies for the fitting room operation through modelling the reactive behaviour of staff and customers of the department. First, we have carried out a validation experiment in which we compared the results from our models to the performance of the real system. This experiment also allowed us to establish differences in output accuracy between the two modelling methids. In a second step a multi-scenario experimen...

  14. Multi-agent modeling for the simulation of a simple smart microgrid

    International Nuclear Information System (INIS)

    Highlights: • We created a systemic modular model for a microgrid with a load flow calculation. • The model is modular and besides the power devices includes also a communication layer. • An agent-based approach allows to include intelligent strategies on every node of the system. • First feasibility simulations were run to show the possible outcomes of generator and load management strategies. - Abstract: The smart grid is a highly complex system that is being formed from the traditional power grid, adding new and sophisticated communication and control devices. This will enable integrating new elements for distributed power generation and also achieving an increasingly automated operation so for actions of the utilities as for customers. In order to model such systems, a bottom-up method is followed, using only a few basic elements which are structured into two layers: a physical layer for the electrical power transmission and one logical layer for element communication. A simple case study is presented to analyze the possibilities of simulation. It shows a microgrid model with dynamic load management and an integrated approach that can process both electrical and communication flows

  15. Simulation of avascular tumor growth by agent-based game model involving phenotype-phenotype interactions.

    Science.gov (United States)

    Chen, Yong; Wang, Hengtong; Zhang, Jiangang; Chen, Ke; Li, Yumin

    2015-01-01

    All tumors, both benign and metastatic, undergo an avascular growth stage with nutrients supplied by the surrounding tissue. This avascular growth process is much easier to carry out in more qualitative and quantitative experiments starting from tumor spheroids in vitro with reliable reproducibility. Essentially, this tumor progression would be described as a sequence of phenotypes. Using agent-based simulation in a two-dimensional spatial lattice, we constructed a composite growth model in which the phenotypic behavior of tumor cells depends on not only the local nutrient concentration and cell count but also the game among cells. Our simulation results demonstrated that in silico tumors are qualitatively similar to those observed in tumor spheroid experiments. We also found that the payoffs in the game between two living cell phenotypes can influence the growth velocity and surface roughness of tumors at the same time. Finally, this current model is flexible and can be easily extended to discuss other situations, such as environmental heterogeneity and mutation. PMID:26648395

  16. Impact of Carbon Quota Allocation Mechanism on Emissions Trading: An Agent-Based Simulation

    Directory of Open Access Journals (Sweden)

    Wei Jiang

    2016-08-01

    Full Text Available This paper establishes an agent-based simulation system of the carbon emissions trading in accordance with the complex feature of the trading process. This system analyzes the impact of the carbon quota allocation mechanism on emissions trading for three different aspects including the amount of emissions reduction, the economic effect on the emitters, and the emissions reduction cost. Based on the data of the carbon emissions of different industries in China, several simulations were made. The results indicate that the emissions trading policy can effectively reduce carbon emissions in a perfectly competitive market. Moreover, by comparing separate quota allocation mechanisms, we obtain the result that the scheme with a small extent quota decrease in a comprehensive allocation mechanism can minimize the unit carbon emission cost. Implementing this scheme can also achieve minimal effects of carbon emissions limitation on the economy on the basis that the environment is not destroyed. However, excessive quota decrease cannot promote the emitters to reduce emission. Taking into account that several developing countries have the dual task of limiting carbon emissions and developing the economy, it is necessary to adopt a comprehensive allocation mechanism of the carbon quota and increase the initial proportion of free allocation.

  17. The contribution of agent-based simulations to conservation management on a Natura 2000 site.

    Science.gov (United States)

    Dupont, Hélène; Gourmelon, Françoise; Rouan, Mathias; Le Viol, Isabelle; Kerbiriou, Christian

    2016-03-01

    The conservation of biodiversity today must include the participation and support of local stakeholders. Natura 2000 can be considered as a conservation system that, in its application in most EU countries, relies on the participation of local stakeholders. Our study proposes a scientific method for participatory modelling, with the aim of contributing to the conservation management of habitats and species at a Natura 2000 site (Crozon Peninsula, Bretagne, France) that is representative of in landuse changes in coastal areas. We make use of companion modelling and its associated tools (scenario-planning, GIS, multi-agent modelling and simulations) to consider possible futures through the co-construction of management scenarios and the understanding of their consequences on different indicators of biodiversity status (habitats, avifauna, flora). The maintenance of human activities as they have been carried out since the creation of the Natura 2000s zone allows the biodiversity values to remain stable. Extensive agricultural activities have been shown to be essential to this maintenance, whereas management sustained by the multiplication of conservation actions brings about variable results according to the indicators. None of the scenarios has a positive incidence on the set of indicators. However, an understanding of the modelling system and the results of the simulations allow for the refining of the selection of conservation actions in relation to the species to be preserved. PMID:26696603

  18. Advances in the FDTD design and modeling of nano- and bio-photonics applications

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Tuchin, Valery; Cheben, Pavel;

    2011-01-01

    address newly emerging problems and not so much on its mathematical formulation. We will first discuss the application of a traditional formulation of the FDTD approach to the modeling of sub-wavelength photonics structures. Next, a modified total/scattered field FDTD approach will be applied to the...... modeling of biophotonics applications including optical phase contrast microscope (OPCM) imaging of cells containing gold nanoparticles (NPs) as well as its potential application as a modality for in vivo flow cytometry configurations. The conclusion provides a justification for the selection of the two...

  19. Analysis of photonic band-gap (PBG) structures using the FDTD method

    DEFF Research Database (Denmark)

    Tong, M.S.; Cheng, M.; Lu, Y.L.;

    2004-01-01

    In this paper, a number of photonic band-gap (PBG) structures, which are formed by periodic circuit elements printed oil transmission-line circuits, are studied by using a well-known numerical method, the finite-difference time-domain (FDTD) method. The results validate the band-stop filter...... behavior of these structures, and the computed results generally match well with ones published in the literature. It is also found that the FDTD method is a robust, versatile, and powerful numerical technique to perform such numerical studies. The proposed PBG filter structures may be applied in microwave...

  20. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    OpenAIRE

    Liu Yang; Qiang Han; Shuya Cao; Feng Huang; Molin Qin; Chenghai Guo; Mingyu Ding

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical an...

  1. Evolutionary perspectives on collective decision making: Studying the implications of diversity and social network structure with agent-based simulations

    CERN Document Server

    Sayama, Hiroki; Yammarino, Francis J

    2013-01-01

    Collective, especially group-based, managerial decision making is crucial in organizations. Using an evolutionary theory approach to collective decision making, agent-based simulations were conducted to investigate how collective decision making would be affected by the agents' diversity in problem understanding and/or behavior in discussion, as well as by their social network structure. Simulation results indicated that groups with consistent problem understanding tended to produce higher utility values of ideas and displayed better decision convergence, but only if there was no group-level bias in collective problem understanding. Simulation results also indicated the importance of balance between selection-oriented (i.e., exploitative) and variation-oriented (i.e., explorative) behaviors in discussion to achieve quality final decisions. Expanding the group size and introducing non-trivial social network structure generally improved the quality of ideas at the cost of decision convergence. Simulations with ...

  2. Autonomous agent-based simulation of an AEGIS Cruiser combat information center performing battle air-defense commander operations

    OpenAIRE

    Calfee, Sharif H.

    2003-01-01

    The AEGIS Cruiser Air-Defense Simulation is a program that models the operations of a Combat Information Center (CIC) team performing the ADC duties in a battle group using Multi-Agent System (MAS) technology implemented in the Java programming language. Set in the Arabian Gulf region, the simulation is a top-view, dynamic, graphics-driven software implementation that provides a picture of the CIC team grappling with a challenging, complex problem. Conceived primarily as a system to assist sh...

  3. MODELING OF INVESTMENT STRATEGIES IN STOCKS MARKETS: AN APPROACH FROM MULTI AGENT BASED SIMULATION AND FUZZY LOGIC

    Directory of Open Access Journals (Sweden)

    ALEJANDRO ESCOBAR

    2010-01-01

    Full Text Available This paper presents a simulation model of a complex system, in this case a financial market, using a MultiAgent Based Simulation approach. Such model takes into account microlevel aspects like the Continuous Double Auction mechanism, which is widely used within stock markets, as well as investor agents reasoning who participate looking for profits. To model such reasoning several variables were considered including general stocks information like profitability and volatility, but also some agent's aspects like their risk tendency. All these variables are incorporated throughout a fuzzy logic approach trying to represent in a faithful manner the kind of reasoning that nonexpert investors have, including a stochastic component in order to model human factors.

  4. Numerical simulation of piezoelectric effect of bone under ultrasound irradiation

    Science.gov (United States)

    Hosokawa, Atsushi

    2015-07-01

    The piezoelectric effect of bone under ultrasound irradiation was numerically simulated using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, to demonstrate the validity of the PE-FDTD method, the ultrasound propagation in piezoelectric ceramics was simulated and then compared with the experimental results. The simulated and experimental waveforms propagating through the ceramics were in good agreement. Next, the piezoelectric effect of human cortical bone on the ultrasound propagation was investigated by PE-FDTD simulation. The simulated result showed that the difference between the waveforms propagating through the bone without and with piezoelectricity was negligible. Finally, the spatial distributions of the electric fields in a human femur induced by ultrasound irradiation were simulated. The electric fields were changed by a bone fracture, which depended on piezoelectric anisotropy. In conclusion, the PE-FDTD method is considered to be useful for investigating the piezoelectric effect of bone.

  5. Irrigation of an established vineyard with winery cleaning agent solution (simulated winery wastewater): vine growth, berry quality, and soil chemistry

    Science.gov (United States)

    The ability to use winery wastewater (WW) for irrigation purposes could be a beneficial to the wine industry. A major difficulty in studying WW use is its inconsistent availability and composition. As such, we applied four simulated WWs composed of salts from two main industrial cleaning agents, and...

  6. Simulating the conversion of rural settlements to town land based on multi-agent systems and cellular automata.

    Directory of Open Access Journals (Sweden)

    Yaolin Liu

    Full Text Available Rapid urbanization in China has triggered the conversion of land from rural to urban use, particularly the conversion of rural settlements to town land. This conversion is the result of the joint effects of the geographic environment and agents involving the government, investors, and farmers. To understand the dynamic interaction dominated by agents and to predict the future landscape of town expansion, a small town land-planning model is proposed based on the integration of multi-agent systems (MAS and cellular automata (CA. The MAS-CA model links the decision-making behaviors of agents with the neighbor effect of CA. The interaction rules are projected by analyzing the preference conflicts among agents. To better illustrate the effects of the geographic environment, neighborhood, and agent behavior, a comparative analysis between the CA and MAS-CA models in three different towns is presented, revealing interesting patterns in terms of quantity, spatial characteristics, and the coordinating process. The simulation of rural settlements conversion to town land through modeling agent decision and human-environment interaction is very useful for understanding the mechanisms of rural-urban land-use change in developing countries. This process can assist town planners in formulating appropriate development plans.

  7. Can Human-Like Bots Control Collective Mood: Agent-Based Simulations of Online Chats

    CERN Document Server

    Tadic, Bosiljka

    2013-01-01

    Using agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ``human-like'' attributes, which exchange emotional messages with agents, are considered, and collective emotional behavior of agents is quantitatively analysed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent's activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate it. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process.Positive-emotion Bots are slightly more effective than the negative ones. Moreover, the Bots which are periodically alternating between positive a...

  8. Collaborative Multi-Agent Based Simulations: Stakeholder-Focused Innovation in Water Resources Management and Decision-Support Modeling

    Science.gov (United States)

    Kock, B. E.

    2006-12-01

    The combined use of multi-agent based simulations and collaborative modeling approaches is emerging as a highly effective tool for representing complex coupled social-biophysical water resource systems. A collaboratively-designed, multi-agent based simulation can be used both as a decision-support tool and as a didactic method for improving stakeholder understanding and engagement with water resources policymaking and management. Major technical and non-technical obstacles remain to the efficient and effective development of multi-agent models of human society, to integrating these models with GIS and other numerical models, and to building a process for engaging stakeholders with model design, implementation and use. It is proposed here to tackle some of these obstacles through a collaborative multi-agent based simulation process framework, intended for practical use in resolving disputes and environmental challenges over sustainable irrigated agriculture in the Western United States. A practical implementation of this framework will be conducted in collaboration with a diverse stakeholder group representing farmers and local, state and federal water managers. Through the use of simulation gaming, interviewing and computer-based knowledge elicitation, a multi-agent model representing local and regional social dynamics will be developed to support the acceptable and sustainable implementation of management alternatives for reducing regional problems of salinization and high selenium concentrations in soils and irrigation water. The development of a socially and scientifically credible simulation platform in this setting can make a significant contribution to ensuring the non-adversarial use of high quality science, enhance the engagement of stakeholders with policymaking, and help meet the challenges of integrating dynamic models of human society with more traditional biophysical systems models.

  9. Application of the FD-TD method to the electromagnetic modeling of patch antenna arrays

    Energy Technology Data Exchange (ETDEWEB)

    Pasik, M.F. [Sandia National Labs., Albuquerque, NM (United States); Aguirre, G.; Cangellaris, A.C. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Electrical and Computer Eengineering, Center for Electronic Packaging Research

    1996-01-10

    FD-TD method and the Berenger Perfectly Matched Layer (PML) absorbing condition are applied to the modeling of a 32-element patch array. Numerical results for the return loss at the array feed are presented and compared to measured results for the purpose of model validation.

  10. Resource-saving application of FDTD technique in 3D photonic crystal waveguide calculations

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Tromborg, Bjarne

    This paper presents an algorithm based on the well-known FDTD numerical method which is adapted for 3D problems of transmission and reflection of photonic crystal waveguides, and which effectively saves memory and computing resources. Specific examples showing its validity and effectiveness are...

  11. An operational epidemiological model for calibrating agent-based simulations of pandemic influenza outbreaks.

    Science.gov (United States)

    Prieto, D; Das, T K

    2016-03-01

    Uncertainty of pandemic influenza viruses continue to cause major preparedness challenges for public health policymakers. Decisions to mitigate influenza outbreaks often involve tradeoff between the social costs of interventions (e.g., school closure) and the cost of uncontrolled spread of the virus. To achieve a balance, policymakers must assess the impact of mitigation strategies once an outbreak begins and the virus characteristics are known. Agent-based (AB) simulation is a useful tool for building highly granular disease spread models incorporating the epidemiological features of the virus as well as the demographic and social behavioral attributes of tens of millions of affected people. Such disease spread models provide excellent basis on which various mitigation strategies can be tested, before they are adopted and implemented by the policymakers. However, to serve as a testbed for the mitigation strategies, the AB simulation models must be operational. A critical requirement for operational AB models is that they are amenable for quick and simple calibration. The calibration process works as follows: the AB model accepts information available from the field and uses those to update its parameters such that some of its outputs in turn replicate the field data. In this paper, we present our epidemiological model based calibration methodology that has a low computational complexity and is easy to interpret. Our model accepts a field estimate of the basic reproduction number, and then uses it to update (calibrate) the infection probabilities in a way that its effect combined with the effects of the given virus epidemiology, demographics, and social behavior results in an infection pattern yielding a similar value of the basic reproduction number. We evaluate the accuracy of the calibration methodology by applying it for an AB simulation model mimicking a regional outbreak in the US. The calibrated model is shown to yield infection patterns closely replicating

  12. Using FLAME Toolkit for Agent-Based Simulation: Case Study Sugarscape Model

    OpenAIRE

    Kiran, Mariam

    2014-01-01

    Social scientists have used agent-based models to understand how individuals interact and behave in various political, ecological and economic scenarios. Agent-based models are ideal for understanding such models involving interacting individuals producing emergent phenomenon. Sugarscape is one of the most famous examples of a social agent-based model which has been used to show how societies grow in the real world. This paper builds on the Sugarscape model, using the Flexible Large scale Age...

  13. Modeling agents with a theory of mind : Theory-theory versus simulation theory

    OpenAIRE

    Harbers, M.; Bosch, K. van den; Meyer, J.J.C.

    2012-01-01

    Virtual training systems with intelligent agents provide an effective means to train people for complex, dynamic tasks like crisis management or firefighting. For successful training, intelligent virtual agents should be able to show believable behavior, adapt their behavior to the trainee’s performance and give useful explanations about their behavior. Agents can provide more believable behavior and explanations if they, besides their own, take the assumed knowledge and intentions of other p...

  14. Agent-based Modeling Simulation Analysis on the Regulation of Institutional Investor's Encroachment Behavior in Stock Market

    Directory of Open Access Journals (Sweden)

    Yang Li

    2014-05-01

    Full Text Available Purpose: This study explores the effective regulation of institutional investor's encroachment behavior in stock market. Given the theoretical and practical importance, the present study examines the effect of the self-adaptive regulation strategy (adjusting the regulation factors such as punishment and the probability of investigating successfully in time for the sake of the small & medium-sized investor protection.Design/methodology/approach: This study was carried out through game theory and agent-based modeling simulation. Firstly, a dynamic game model was built to search the core factors of regulation and the equilibrium paths. Secondly, an agent-based modeling simulation model was built in Swarm to extend the game model. Finally, a simulation experiment (using virtual parameter values was performed to examine the effect of regulation strategy obtained form game model.Findings: The results of this study showed that the core factors of avoiding the institutional investor's encroachment behavior are the punishment and the probability of investigating successfully of the regulator. The core factors embody as the self-adaptability and the capability of regulator. If the regulator can adjust the regulation factors in time, the illegal behaviors will be avoided effectively.Research limitations/implications: The simulation experiment in this paper was performed with virtual parameter values. Although the results of experiment showed the effect of self-adaptive regulation, there are still some differences between simulation experiment and real market situation.Originality/value: The purpose of this study is to investigate an effective regulation strategy of institutional investor's encroachment behavior in stock market in order to maintain market order and protect the benefits of investors. Base on the game model and simulation model, a simulation experiment was preformed and the result showed that the self-adaptive regulation would be effective

  15. Linking Bayesian and Agent-Based Models to Simulate Complex Social-Ecological Systems in the Sonoran Desert

    Science.gov (United States)

    Pope, A.; Gimblett, R.

    2013-12-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent's water demand. Depth-to-groundwater was then used as an indicator of unique vegetation guilds within the riparian corridor. Each vegetation guild provides varying levels of ecosystem services, the changes of which, along with changes in depth-to-groundwater, feedback to influence agent behavior. Using this modeling approach allowed us to examine resilience of semi-arid riparian corridors and agent behavior under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  16. Interaction of Classical Platinum Agents with the Monomeric and Dimeric Atox1 Proteins: A Molecular Dynamics Simulation Study

    Directory of Open Access Journals (Sweden)

    Xiaolei Wang

    2013-12-01

    Full Text Available We carried out molecular dynamics simulations and free energy calculations for a series of binary and ternary models of the cisplatin, transplatin and oxaliplatin agents binding to a monomeric Atox1 protein and a dimeric Atox1 protein to investigate their interaction mechanisms. All three platinum agents could respectively combine with the monomeric Atox1 protein and the dimeric Atox1 protein to form a stable binary and ternary complex due to the covalent interaction of the platinum center with the Atox1 protein. The results suggested that the extra interaction from the oxaliplatin ligand–Atox1 protein interface increases its affinity only for the OxaliPt + Atox1 model. The binding of the oxaliplatin agent to the Atox1 protein might cause larger deformation of the protein than those of the cisplatin and transplatin agents due to the larger size of the oxaliplatin ligand. However, the extra interactions to facilitate the stabilities of the ternary CisPt + 2Atox1 and OxaliPt + 2Atox1 models come from the α1 helices and α2-β4 loops of the Atox1 protein–Atox1 protein interface due to the cis conformation of the platinum agents. The combinations of two Atox1 proteins in an asymmetric way in the three ternary models were analyzed. These investigations might provide detailed information for understanding the interaction mechanism of the platinum agents binding to the Atox1 protein in the cytoplasm.

  17. Design, Validation, Simulation and Parametric Evaluation of a Novel Protocol for Locating Mobile Agents in Multiregion Environment

    Directory of Open Access Journals (Sweden)

    Rama Sushil

    2008-01-01

    Full Text Available Mobile agents are processes that can be dispatched from source computer and be transported to remote servers for execution, have been widely argued to be an important enabling technology for future systems. Location management is a necessity for locating mobile agents in a network of mobile agent hosts for controlling, monitoring and communication during processing and it still represents an open research issue. The cost of location management strategies mainly depends on the cost of search and update. We concentrated on reducing the cost of update and improving the speed of processing of the agents. We proposed a location management technique applicable for multi-region environment in which mobile agent did not update its location at every migration. The technique named as Broadcasting with Search by Path Chase (BSPC. We used the tool time Petri net analyzer TINA to model, analyze and to simulate BSPC. We found that the BSPC behaves as expected and free from any deadlock. We measured the efficiency of BSPC and compared with some existing location management techniques by parametric evaluation. BSPC provided better scalability, location updating availability and interaction fault rate with theoretical considerations of network usage and network fault rate. It gave its best performance for applications of low CMR and having high migration rate of mobile agents within birth region.

  18. 3-D ADI-FDTD modeling of GPR backscatter from complex targets for the training of artificial neural networks

    Science.gov (United States)

    Sassen, D. S.; Everett, M. E.

    2007-12-01

    Artificial neural networks can provide approximate solutions to ground-penetrating radar (GPR) problems in cases where real time performance is needed. Examples include discrimination of landmines or UXO's, and in circumstances that require a high number of successive forward problems, for example inversion or imaging. The training of neural networks to work within even a limited range of targets and electromagnetic properties requires a large set of successive examples generated from numerical methods such as finite difference time domain (FDTD). The traditional FDTD technique suffers from numerical dispersion unless time steps are kept below the Courant stability limit. The accurate modeling of electromagnetic scattering by complex targets require a refined grid, subgrids, or conformal grids that can significantly increase computation time, making neural network training inefficient. A relatively recent FDTD technique, ADI-FDTD, uses implicit equations that help to cancel numerical dispersion and allow for unconditionally stable modeling of EM propagation and therefore is not bound by the Courant stability limit. The technique is especially efficient for the accurate modeling of complex targets. Our ADI-FDTD code includes the ability to refine the model grid and to implement a conformal gridding to improve model accuracy without effecting the overall computation time. We will explore the tradeoff in computation time and accuracy in modeling the GPR backscatter of various targets using both the ADI-FDTD technique and the traditional FDTD technique for the purpose of neural network training.

  19. Scattered-field FDTD and PSTD algorithms with CPML absorbing boundary conditions for light scattering by aerosols

    International Nuclear Information System (INIS)

    As fundamental parameters for polarized-radiative-transfer calculations, the single-scattering phase matrix of irregularly shaped aerosol particles must be accurately modeled. In this study, a scattered-field finite-difference time-domain (FDTD) model and a scattered-field pseudo-spectral time-domain (PSTD) model are developed for light scattering by arbitrarily shaped dielectric aerosols. The convolutional perfectly matched layer (CPML) absorbing boundary condition (ABC) is used to truncate the computational domain. It is found that the PSTD method is generally more accurate than the FDTD in calculation of the single-scattering properties given similar spatial cell sizes. Since the PSTD can use a coarser grid for large particles, it can lower the memory requirement in the calculation. However, the Fourier transformations in the PSTD need significantly more CPU time than simple subtractions in the FDTD, and the fast Fourier transform requires a power of 2 elements in calculations, thus using the PSTD could not significantly reduce the CPU time required in the numerical modeling. Furthermore, because the scattered-field FDTD/PSTD equations include incident-wave source terms, the FDTD/PSTD model allows for the inclusion of an arbitrarily incident wave source, including a plane parallel wave or a Gaussian beam like those emitted by lasers usually used in laboratory particle characterizations, etc. The scattered-field FDTD and PSTD light-scattering models can be used to calculate single-scattering properties of arbitrarily shaped aerosol particles over broad size and wavelength ranges. -- Highlights: • Scattered-field FDTD and PSTD models are developed for light scattering by aerosols. • Convolutional perfectly matched layer absorbing boundary condition is used. • PSTD is generally more accurate than FDTD in calculating single-scattering properties. • Using same spatial resolution, PSTD requires much larger CPU time than FDTD

  20. Effect of Antifoam Agent on Oxidative Leaching of Hanford Tank Sludge Simulants

    Energy Technology Data Exchange (ETDEWEB)

    Rapko, Brian M.; Jones, Susan A.; Lumetta, Gregg J.; Peterson, Reid A.

    2010-02-26

    Oxidative leaching of simulant tank waste containing an antifoam agent (AFA) to reduce the chromium content of the sludge was tested using permanganate as the oxidant in 0.25 M NaOH solutions. AFA is added to the waste treatment process to prevent foaming. The AFA, Dow Corning Q2-3183A, is a surface-active polymer that consists of polypropylene glycol, polydimethylsiloxane, octylphenoxy polyethoxy ethanol, treated silica, and polyether polyol. Some of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste slurries contain high concentrations of undissolved solids that would exhibit undesirable behavior without AFA addition. These tests were conducted to determine the effect of the AFA on oxidative leaching of Cr(III) in waste by permanganate. It has not previously been determined what effect AFA has on the permanganate reaction. This study was conducted to determine the effect AFA has on the oxidation of the chromium, plus plutonium and other criticality-related elements, specifically Fe, Ni and Mn. During the oxidative leaching process, Mn is added as liquid permanganate solution and is converted to an insoluble solid that precipitates as MnO2 and becomes part of the solid waste. Caustic leaching was performed followed by an oxidative leach at either 25°C or 45°C. Samples of the leachate and solids were collected at each step of the process. Initially, Battelle-Pacific Northwest Division (PNWD) was contracted by Bechtel National, Inc. to perform these further scoping studies on oxidative alkaline leaching. The data obtained from the testing will be used by the WTP operations to develop procedures for permanganate dosing of Hanford tank sludge solids during oxidative leaching. Work was initially conducted under contract number 24590-101-TSA-W000-00004. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) operating Contract DE-AC05-76RL01830. In summary, this report describes work focused on

  1. Effect of Antifoam Agent on Oxidative Leaching of Hanford Tank Sludge Simulants

    International Nuclear Information System (INIS)

    Oxidative leaching of simulant tank waste containing an antifoam agent (AFA) to reduce the chromium content of the sludge was tested using permanganate as the oxidant in 0.25 M NaOH solutions. AFA is added to the waste treatment process to prevent foaming. The AFA, Dow Corning Q2-3183A, is a surface-active polymer that consists of polypropylene glycol, polydimethylsiloxane, octylphenoxy polyethoxy ethanol, treated silica, and polyether polyol. Some of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste slurries contain high concentrations of undissolved solids that would exhibit undesirable behavior without AFA addition. These tests were conducted to determine the effect of the AFA on oxidative leaching of Cr(III) in waste by permanganate. It has not previously been determined what effect AFA has on the permanganate reaction. This study was conducted to determine the effect AFA has on the oxidation of the chromium, plus plutonium and other criticality-related elements, specifically Fe, Ni and Mn. During the oxidative leaching process, Mn is added as liquid permanganate solution and is converted to an insoluble solid that precipitates as MnO2 and becomes part of the solid waste. Caustic leaching was performed followed by an oxidative leach at either 25 C or 45 C. Samples of the leachate and solids were collected at each step of the process. Initially, Battelle-Pacific Northwest Division (PNWD) was contracted by Bechtel National, Inc. to perform these further scoping studies on oxidative alkaline leaching. The data obtained from the testing will be used by the WTP operations to develop procedures for permanganate dosing of Hanford tank sludge solids during oxidative leaching. Work was initially conducted under contract number 24590-101-TSA-W000-00004. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) operating Contract DE-AC05-76RL01830. In summary, this report describes work focused on determining

  2. Can human-like Bots control collective mood: agent-based simulations of online chats

    Science.gov (United States)

    Tadić, Bosiljka; Šuvakov, Milovan

    2013-10-01

    Using an agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ‘human-like’ attributes, which exchange emotional messages with agents, are considered, and the collective emotional behavior of agents is quantitatively analyzed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate that impact. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process. Positive emotion Bots are slightly more effective than negative emotion Bots. Moreover, Bots which periodically alternate between positive and negative emotion can enhance fluctuations in the system, leading to avalanches of agent messages that are reminiscent of self-organized critical states.

  3. Modeling agents with a theory of mind : Theory-theory versus simulation theory

    NARCIS (Netherlands)

    Harbers, M.; Bosch, K. van den; Meyer, J.J.C.

    2012-01-01

    Virtual training systems with intelligent agents provide an effective means to train people for complex, dynamic tasks like crisis management or firefighting. For successful training, intelligent virtual agents should be able to show believable behavior, adapt their behavior to the trainee’s perform

  4. Can human-like Bots control collective mood: agent-based simulations of online chats

    International Nuclear Information System (INIS)

    Using an agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ‘human-like’ attributes, which exchange emotional messages with agents, are considered, and the collective emotional behavior of agents is quantitatively analyzed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate that impact. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process. Positive emotion Bots are slightly more effective than negative emotion Bots. Moreover, Bots which periodically alternate between positive and negative emotion can enhance fluctuations in the system, leading to avalanches of agent messages that are reminiscent of self-organized critical states. (paper)

  5. Simulation of the Emotion Dynamics in a Group of Agents in an Evacuation Situation

    OpenAIRE

    Le, Minh; Adam, Carole; Canal, Richard; Gaudou, Benoit; HO, Tuong Vinh; Taillandier, Patrick

    2010-01-01

    Nowadays, more and more emergency evacuation simulations are used to evaluate the safety level of a building during an emergency evacuation after an accident. The heart of this kind of simulations is the simulation of human behavior because simulation results depend for a big part on how this behavior is simulated. However, human behaviors in a real emergency situation are determined by a lot of cognitive mechanisms. In order to make the simulation more realistic, plenty of factors (e.g. inna...

  6. Partially Loaded Cavity Analysis by Using the 2-D FDTD Method

    Institute of Scientific and Technical Information of China (English)

    YAO Bin; ZHENG Qin-Hong; PENG Jin-Hui; ZHONG Ru-Neng; XIANG Tai; XU Wan-Song

    2011-01-01

    A compact two-dimensional (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors ofa partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x-y plane.With the description of z dependence by kz,the three-dimensional (3-D) problem can be transformed into a 2-D problem.Therefore,less memory and CPU time are required as compared to the conventional 3-D FDTD method.Three representative examples,a half-loaded rectangular cavity,an inhomogeneous cylindrical cavity and a cubic cavity loaded with dielectric post,are presented to validate the utility and efficiency of the proposed method.Since the finite-difference time-domain (FDTD)method was first introduced by Yee,[1] it has been widely used to solve electromagnetic problems.[2,3]Among them,endeavors have been made to achieve faster resonator computation and some numerical techniques have been combined with the FDTD method for faster computation.The numerical teehniques include digital filtering,the modern spectrum estimation technique,Prony analysis,Padé approximation and the Baker algorithm.[4-8] Benefiting from these techniques,the analysis time of resonators has been greatly reduced.However,there are two deficiencies in the above-mentioned literature.First,these approaches are still based on a three-dimensional (3-D)mesh,which needs numerous computational resources.%A compact two-dimensioned (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors of a partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x-y plane. With the description of z dependence by kz, the three-dimensional (3-D) problem can be transformed into a 2-D problem. Therefore, less memory and CPU time are required as compared to the conventional 3-D FDTD method. Three representative examples, a half-loaded rectangular cavity, an

  7. Simulating Land-Use Change using an Agent-Based Land Transaction Model

    Science.gov (United States)

    Bakker, M. M.; van Dijk, J.; Alam, S. J.

    2013-12-01

    In the densely populated cultural landscapes of Europe, the vast majority of all land is owned by private parties, be it farmers (the majority), nature organizations, property developers, or citizens. Therewith, the vast majority of all land-use change arises from land transactions between different owner types: successful farms expand at the expense of less successful farms, and meanwhile property developers, individual citizens, and nature organizations also actively purchase land. These land transactions are driven by specific properties of the land, by governmental policies, and by the (economic) motives of both buyers and sellers. Climate/global change can affect these drivers at various scales: at the local scale changes in hydrology can make certain land less or more desirable; at the global scale the agricultural markets will affect motives of farmers to buy or sell land; while at intermediate (e.g. provincial) scales property developers and nature conservationists may be encouraged or discouraged to purchase land. The cumulative result of all these transactions becomes manifest in changing land-use patterns, and consequent environmental responses. Within the project Climate Adaptation for Rural Areas an agent-based land-use model was developed that explores the future response of individual land users to climate change, within the context of wider global change (i.e. policy and market change). It simulates the exchange of land among farmers and between farmers and nature organizations and property developers, for a specific case study area in the east of the Netherlands. Results show that local impacts of climate change can result in a relative stagnation in the land market in waterlogged areas. Furthermore, the increase in dairying at the expense of arable cultivation - as has been observed in the area in the past - is slowing down as arable produce shows a favourable trend in the agricultural world market. Furthermore, budgets for nature managers are

  8. Modelling and simulation of electrical energy systems through a complex systems approach using agent-based models

    Energy Technology Data Exchange (ETDEWEB)

    Kremers, Enrique

    2013-10-01

    Complexity science aims to better understand the processes of both natural and man-made systems which are composed of many interacting entities at different scales. A disaggregated approach is proposed for simulating electricity systems, by using agent-based models coupled to continuous ones. The approach can help in acquiring a better understanding of the operation of the system itself, e.g. on emergent phenomena or scale effects; as well as in the improvement and design of future smart grids.

  9. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Gimblett, Randy

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio So...

  10. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Randy eGimblett

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio ...

  11. CaTMAS : A multi-agent model for simulating the dynamics of carbon resources of West African villages

    OpenAIRE

    Belem, Mahamadou; Manlay, R. J.; Muller, J.P.; Chotte, Jean-Luc

    2011-01-01

    Carbon is an important determinant of the sustainability of West African farming systems and of the atmospheric greenhouse effect. Given the complexity of C dynamics, various simulation models have been developed. Few include socioeconomic factors or handle system heterogeneity. This study proposes a generic, multi-agent model for the analysis of C dynamics at village level. It assumes that a better analysis of carbon dynamics at village level requires account to be taken of social, economic,...

  12. Alternative Supply Chain Production-Sales Policies for New Product Diffusion: An Agent-Based Modeling and Simulation Approach

    OpenAIRE

    Amini, Mehdi; Wakolbinger, Tina; Racer, Michael; Nejad, Mohammed G.

    2012-01-01

    Applying Agent-Based Modeling and Simulation (ABMS) methodology, this paper analyzes the impact of alternative production-sales policies on the diffusion of a new product and the generated NPV of profit. The key features of the ABMS model, that captures the marketplace as a complex adaptive system, are: (i) supply chain capacity is constrained; (ii) consumers' new product adoption decisions are influenced by marketing activities as well as positive and negative word of mouth (W...

  13. Multi-Agent Based Simulation of Optimal Urban Land Use Allocation in the Middle Reaches of the Yangtze River, China

    Science.gov (United States)

    Zeng, Y.; Huang, W.; Jin, W.; Li, S.

    2016-06-01

    The optimization of land-use allocation is one of important approaches to achieve regional sustainable development. This study selects Chang-Zhu-Tan agglomeration as study area and proposed a new land use optimization allocation model. Using multi-agent based simulation model, the future urban land use optimization allocation was simulated in 2020 and 2030 under three different scenarios. This kind of quantitative information about urban land use optimization allocation and urban expansions in future would be of great interest to urban planning, water and land resource management, and climate change research.

  14. Real-Time Agent-Based Modeling Simulation with in-situ Visualization of Complex Biological Systems

    Science.gov (United States)

    Seekhao, Nuttiiya; Shung, Caroline; JaJa, Joseph; Mongeau, Luc; Li-Jessen, Nicole Y. K.

    2016-01-01

    We present an efficient and scalable scheme for implementing agent-based modeling (ABM) simulation with In Situ visualization of large complex systems on heterogeneous computing platforms. The scheme is designed to make optimal use of the resources available on a heterogeneous platform consisting of a multicore CPU and a GPU, resulting in minimal to no resource idle time. Furthermore, the scheme was implemented under a client-server paradigm that enables remote users to visualize and analyze simulation data as it is being generated at each time step of the model. Performance of a simulation case study of vocal fold inflammation and wound healing with 3.8 million agents shows 35× and 7× speedup in execution time over single-core and multi-core CPU respectively. Each iteration of the model took less than 200 ms to simulate, visualize and send the results to the client. This enables users to monitor the simulation in real-time and modify its course as needed. PMID:27547508

  15. Representing a Combat ID Analysis Tool within an Agent Based Constructive Simulation

    NARCIS (Netherlands)

    Dean, D.; Mistry, B.; Spaans, M.; Vincent, A.; Hossain, A.

    2009-01-01

    Motivation - This paper describes an approach for the development of a model which represents complex human factors relationships relating to Combat Identification (Combat ID). Research approach - The human factors relationships were incorporated within an experimental Agent Based Model (ABM), using

  16. Diffusion dynamics and concentration of toxic materials from quantum dots-based nanotechnologies: an agent-based modeling simulation framework

    Energy Technology Data Exchange (ETDEWEB)

    Agusdinata, Datu Buyung, E-mail: bagusdinata@niu.edu; Amouie, Mahbod [Northern Illinois University, Department of Industrial & Systems Engineering and Environment, Sustainability, & Energy Institute (United States); Xu, Tao [Northern Illinois University, Department of Chemistry and Biochemistry (United States)

    2015-01-15

    Due to their favorable electrical and optical properties, quantum dots (QDs) nanostructures have found numerous applications including nanomedicine and photovoltaic cells. However, increased future production, use, and disposal of engineered QD products also raise concerns about their potential environmental impacts. The objective of this work is to establish a modeling framework for predicting the diffusion dynamics and concentration of toxic materials released from Trioctylphosphine oxide-capped CdSe. To this end, an agent-based model simulation with reaction kinetics and Brownian motion dynamics was developed. Reaction kinetics is used to model the stability of surface capping agent particularly due to oxidation process. The diffusion of toxic Cd{sup 2+} ions in aquatic environment was simulated using an adapted Brownian motion algorithm. A calibrated parameter to reflect sensitivity to reaction rate is proposed. The model output demonstrates the stochastic spatial distribution of toxic Cd{sup 2+} ions under different values of proxy environmental factor parameters. With the only chemistry considered was oxidation, the simulation was able to replicate Cd{sup 2+} ion release from Thiol-capped QDs in aerated water. The agent-based method is the first to be developed in the QDs application domain. It adds both simplicity of the solubility and rate of release of Cd{sup 2+} ions and complexity of tracking of individual atoms of Cd at the same time.

  17. Diffusion dynamics and concentration of toxic materials from quantum dots-based nanotechnologies: an agent-based modeling simulation framework

    International Nuclear Information System (INIS)

    Due to their favorable electrical and optical properties, quantum dots (QDs) nanostructures have found numerous applications including nanomedicine and photovoltaic cells. However, increased future production, use, and disposal of engineered QD products also raise concerns about their potential environmental impacts. The objective of this work is to establish a modeling framework for predicting the diffusion dynamics and concentration of toxic materials released from Trioctylphosphine oxide-capped CdSe. To this end, an agent-based model simulation with reaction kinetics and Brownian motion dynamics was developed. Reaction kinetics is used to model the stability of surface capping agent particularly due to oxidation process. The diffusion of toxic Cd2+ ions in aquatic environment was simulated using an adapted Brownian motion algorithm. A calibrated parameter to reflect sensitivity to reaction rate is proposed. The model output demonstrates the stochastic spatial distribution of toxic Cd2+ ions under different values of proxy environmental factor parameters. With the only chemistry considered was oxidation, the simulation was able to replicate Cd2+ ion release from Thiol-capped QDs in aerated water. The agent-based method is the first to be developed in the QDs application domain. It adds both simplicity of the solubility and rate of release of Cd2+ ions and complexity of tracking of individual atoms of Cd at the same time

  18. Multi-Agent Reinforcement Learning Simulation for Multi-Joined Robot

    OpenAIRE

    Kabysh, A.; Golovko, V.

    2012-01-01

    This paper describes a multi-agent influence learning approach and reinforcement learning adaptation to it. This learning technique used for distributed, adaptive and self-organizing control in multi-agent system. This technique is quite simple and uses agent’s influences to estimate learning error between them. The best influences is rewarded via reinforcement learning which is well proven learning technique. As will show, this learning rule supports positive-reward i...

  19. FDTD Simulation on Power Absorption of Terahertz Electromagnetic Waves in Dense Plasma%FDTD Simulation on Power Absorption of Terahertz Electromagnetic Waves in Dense Plasma

    Institute of Scientific and Technical Information of China (English)

    奚衍斌; 刘悦

    2012-01-01

    A finite difference time domain (FDTD) method is used to numerically study the power absorption of broadband terahertz (0.1 - 1.5 THz) electromagnetic waves in a partially ionized uniform plasma layer under low pressure and atmosphere discharge conditions. The power absorption spectra are calculated numerically and the numerical results are in accordance with the analytic results. Meanwhile, the effects on the power absorption are calculated with different applied magnetic fields, collision frequencies and electron number densities, which depend strongly on those parameters. Under the dense strongly magnetized plasma conditions, the absorption gaps appear in the range of 0.3 - 0.36 THz, and are enlarged with the increasing electron number density.

  20. FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Zamorano, M; Torres-Silva, H [Departamento de Electronica, Universidad de Tarapaca, 18 de Septiembre 2222, Arica (Chile)

    2006-04-07

    A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source.

  1. Integrating the simulation of domestic water demand behaviour to an urban water model using agent based modelling

    Science.gov (United States)

    Koutiva, Ifigeneia; Makropoulos, Christos

    2015-04-01

    The urban water system's sustainable evolution requires tools that can analyse and simulate the complete cycle including both physical and cultural environments. One of the main challenges, in this regard, is the design and development of tools that are able to simulate the society's water demand behaviour and the way policy measures affect it. The effects of these policy measures are a function of personal opinions that subsequently lead to the formation of people's attitudes. These attitudes will eventually form behaviours. This work presents the design of an ABM tool for addressing the social dimension of the urban water system. The created tool, called Urban Water Agents' Behaviour (UWAB) model, was implemented, using the NetLogo agent programming language. The main aim of the UWAB model is to capture the effects of policies and environmental pressures to water conservation behaviour of urban households. The model consists of agents representing urban households that are linked to each other creating a social network that influences the water conservation behaviour of its members. Household agents are influenced as well by policies and environmental pressures, such as drought. The UWAB model simulates behaviour resulting in the evolution of water conservation within an urban population. The final outcome of the model is the evolution of the distribution of different conservation levels (no, low, high) to the selected urban population. In addition, UWAB is implemented in combination with an existing urban water management simulation tool, the Urban Water Optioneering Tool (UWOT) in order to create a modelling platform aiming to facilitate an adaptive approach of water resources management. For the purposes of this proposed modelling platform, UWOT is used in a twofold manner: (1) to simulate domestic water demand evolution and (2) to simulate the response of the water system to the domestic water demand evolution. The main advantage of the UWAB - UWOT model

  2. Partially Loaded Cavity Analysis by Using the 2-D FDTD Method

    International Nuclear Information System (INIS)

    A compact two-dimensional (2-D) finite-difference time-domain (FDTD) method is proposed to calculate the resonant frequencies and quality factors of a partially loaded cavity that is uniform in the z-direction and has an arbitrary cross section in the x—y plane. With the description of z dependence by kz, the three-dimensional (3-D) problem can be transformed into a 2-D problem. Therefore, less memory and CPU time are required as compared to the conventional 3-D FDTD method. Three representative examples, a half-loaded rectangular cavity, an inhomogeneous cylindrical cavity and a cubic cavity loaded with dielectric post, are presented to validate the utility and efficiency of the proposed method. (cross-disciplinary physics and related areas of science and technology)

  3. An FFT-accelerated fdtd scheme with exact absorbing conditions for characterizing axially symmetric resonant structures

    KAUST Repository

    Sirenko, Kostyantyn

    2011-01-01

    An accurate and efficient finite-difference time-domain (FDTD) method for characterizing transient waves interactions on axially symmetric structures is presented. The method achieves its accuracy and efficiency by employing localized and/or fast Fourier transform (FFT) accelerated exact absorbing conditions (EACs). The paper details the derivation of the EACs, discusses their implementation and discretization in an FDTD method, and proposes utilization of a blocked-FFT based algorithm for accelerating the computation of temporal convolutions present in nonlocal EACs. The proposed method allows transient analyses to be carried for long time intervals without any loss of accuracy and provides reliable numerical data pertinent to physical processes under resonant conditions. This renders the method highly useful in characterization of high-Q microwave radiators and energy compressors. Numerical results that demonstrate the accuracy and efficiency of the method are presented.

  4. Study on High Performance of MPI-Based Parallel FDTD from WorkStation to Super Computer Platform

    OpenAIRE

    Z. L. HE; Huang, K.; Zhang, Y.; Yan, Y; Liang, C.H.

    2012-01-01

    Parallel FDTD method is applied to analyze the electromagnetic problems of the electrically large targets on super computer. It is well known that the more the number of processors the less computing time consumed. Nevertheless, with the same number of processors, computing efficiency is affected by the scheme of the MPI virtual topology. Then, the influence of different virtual topology schemes on parallel performance of parallel FDTD is studied in detail. The general rules are presented on ...

  5. Transient Response of Thin Wire above a Layered Half-Space Using TDIE/FDTD Hybrid Method

    Directory of Open Access Journals (Sweden)

    Bing Wei

    2012-01-01

    Full Text Available The TDIE/FDTD hybrid method is applied to calculate the transient responses of thin wire above a lossy layered half-space. The time-domain reflection of the layered half space is computed by one-dimensional modified FDTD method. Then, transient response of thin wire induced by two excitation sources (the incident wave and reflected wave is calculated by TDIE method. Finally numerical results are given to illustrate the feasibility and high efficiency of the presented scheme.

  6. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    Directory of Open Access Journals (Sweden)

    Aloah J Pope

    2015-08-01

    Full Text Available Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio Sonora Watershed. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent’s water demand. Changes in depth-to-groundwater feedback to influence agent behavior, as well as determine unique vegetation classes within the riparian corridor. Each vegetation class then provides varying stakeholder-defined quality values of ecosystem services. Using this modeling approach allowed us to examine effects on both the ecological and social system of semi-arid riparian corridors under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  7. FDTD Studies of Metallic Cylinder Arrays:Plasmon Waveguide and Y-Splitter

    Institute of Scientific and Technical Information of China (English)

    ZHAN Chun-Lin; REN Xi-Feng; HUANG Yun-Feng; DUAN Kai-Min; Guo Guang-Can

    2008-01-01

    The plasmon waveguide based on double chain of gold cylinders is studied using the finite-difference time-domain method(FDTD).The wavelength of the incident Gaussian beam ranges from 650 to 1200nm,and the correspondjng attenuation factors are calculated.We also present a Y-splitter with 90° splitting angle,each branch in the form of double chains.The transmission effiencies for different wavelengths are evaluated.

  8. An FDTD method with FFT-accelerated exact absorbing boundary conditions

    KAUST Repository

    Sirenko, Kostyantyn

    2011-07-01

    An accurate and efficient finite-difference time-domain (FDTD) method for analyzing axially symmetric structures is presented. The method achieves its accuracy and efficiency using exact absorbing conditions (EACs) for terminating the computation domain and a blocked-FFT based scheme for accelerating the computation of the temporal convolutions present in non-local EACs. The method is shown to be especially useful in characterization of long-duration resonant wave interactions. © 2011 IEEE.

  9. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij

    simulations and analytical theory to describe this effect and created a program for fast, realistic simulation of transverse relaxation in perfused tissues. We performed simulations for gray matter and white matter. The predicted values of the relaxivity are in agreement with the relaxivity found in animal...

  10. Investigation of Wave Propagation in Different Dielectric Media by Using Finite Difference Time Domain (FDTD Method

    Directory of Open Access Journals (Sweden)

    Md. Kamal Hossain

    2010-10-01

    Full Text Available In this paper, the wave propagation in free space and different dielectric material by using Finite Difference Time Domain (FDTD method has been studied. Among various numerical methods Finite Difference Time Domain method is being used to study the time evolution behavior of electromagnetic field by solving the Maxwell’sequation in time domain. In this paper, FDTD method has been employed to study the wave propagation in free space and different dielectric materials. The wave equations are discretized in time and space as required by this FDTD method and leaf-frog algorithm is used to find the solution. We observed wave propagation for one and two dimensional cases. We also observed wave propagation through lossy medium for one dimensional case. For two dimensional cases the patterns of wave incident on rectangular dielectric slab, square metal, RCC pillar were observed. In order to visualize the wave propagation, the evaluation of the excitation at various locations of problem space is monitored. The numerical results agree with the propagation characteristics as expected.

  11. Using the Integration of Discrete Event and Agent-Based Simulation to Enhance Outpatient Service Quality in an Orthopedic Department

    Directory of Open Access Journals (Sweden)

    Cholada Kittipittayakorn

    2016-01-01

    Full Text Available Many hospitals are currently paying more attention to patient satisfaction since it is an important service quality index. Many Asian countries’ healthcare systems have a mixed-type registration, accepting both walk-in patients and scheduled patients. This complex registration system causes a long patient waiting time in outpatient clinics. Different approaches have been proposed to reduce the waiting time. This study uses the integration of discrete event simulation (DES and agent-based simulation (ABS to improve patient waiting time and is the first attempt to apply this approach to solve this key problem faced by orthopedic departments. From the data collected, patient behaviors are modeled and incorporated into a massive agent-based simulation. The proposed approach is an aid for analyzing and modifying orthopedic department processes, allows us to consider far more details, and provides more reliable results. After applying the proposed approach, the total waiting time of the orthopedic department fell from 1246.39 minutes to 847.21 minutes. Thus, using the correct simulation model significantly reduces patient waiting time in an orthopedic department.

  12. Using the Integration of Discrete Event and Agent-Based Simulation to Enhance Outpatient Service Quality in an Orthopedic Department.

    Science.gov (United States)

    Kittipittayakorn, Cholada; Ying, Kuo-Ching

    2016-01-01

    Many hospitals are currently paying more attention to patient satisfaction since it is an important service quality index. Many Asian countries' healthcare systems have a mixed-type registration, accepting both walk-in patients and scheduled patients. This complex registration system causes a long patient waiting time in outpatient clinics. Different approaches have been proposed to reduce the waiting time. This study uses the integration of discrete event simulation (DES) and agent-based simulation (ABS) to improve patient waiting time and is the first attempt to apply this approach to solve this key problem faced by orthopedic departments. From the data collected, patient behaviors are modeled and incorporated into a massive agent-based simulation. The proposed approach is an aid for analyzing and modifying orthopedic department processes, allows us to consider far more details, and provides more reliable results. After applying the proposed approach, the total waiting time of the orthopedic department fell from 1246.39 minutes to 847.21 minutes. Thus, using the correct simulation model significantly reduces patient waiting time in an orthopedic department. PMID:27195606

  13. FDTD method based electromagnetic solver for printed-circuit analysis

    OpenAIRE

    Gnilenko, Alexey B.; Paliy, Oleg V.

    2003-01-01

    An electromagnetic solver for printed-circuit analysis is presented. The electromagnetic simulator is based on the finite-difference time-domain method with first-order Mur's absorbing boundary conditions. The solver environment comprises a layout graphic editor for circuit topology preparation and a data postprocessor for presenting the calculation results. The solver has been applied to the analysis of printed-circuit components such as printed antenna, microstrip discontinuities, etc.

  14. 基于 FDTD 的粗糙地面宽带前向电磁散射研究%Study on broadband forward electromagnetic scattering from rough land surface based on FDTD

    Institute of Scientific and Technical Information of China (English)

    武剑; 任新成; 朱小敏

    2015-01-01

    采用指数型分布粗糙面模拟实际的粗糙地面,运用 FDTD 方法研究了超宽带高斯脉冲电磁波入射粗糙地面时的宽带前向电磁散射问题;通过数值计算得到前向散射系数随频率的变化曲线,并与时谐场源激励下的结果进行了对比;分析了不同的粗糙地面高度起伏相关长度、均方根高度,土壤湿度和入射角下前向散射系数随频率的变化关系,得到了指数型分布粗糙地面的宽带前向电磁散射特性。数值计算结果表明各参数的变化对前向电磁散射系数的影响比较明显,入射波不同极化方式下的前向散射系数也有显著变化。%The actual rough land surface is simulated with the exponential type distribution rough surface,the wide-band forward electromagnetic scattering from rough land surface under UWB Gaussian pulse electromagnetic wave incidence is studied using FDTD.The curves of forward electromagnetic scattering coefficient varied with frequency are obtained by numerical calculation,and compared with result under harmonic field source.The forward electromagnetic scattering coefficient varying with frequency is analyzed under the difference of the correlation length and the root-mean-square of rough land height fluctuation,the moisture capacity of soil,the incidence angle.The characteristics of the wide-band forward electromagnetic scattering from rough land surface are obtained.The numerical results show that the influence of various parameters on the forward electromagnetic scattering coefficient is obvious.Moreover,forward scattering coefficient with the changes of the incident polarization modes is also significantly different.

  15. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  16. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    Science.gov (United States)

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  17. Cooperative Electronic Attack for Groups of Unmanned Air Vehicles based on Multi-agent Simulation and Evaluation

    Directory of Open Access Journals (Sweden)

    Yee Ming Chen

    2012-03-01

    Full Text Available In this paper, the issue of path planning is addressed for unmanned air vehicles (UAVs cooperative joint-forces electronic attack operating in a hostile environment. Specifically, the objective is to plan path to a target location in a way that minimizes exposure to threats while keeping fuel usage at acceptable levels. We consider a scenario where a group of UAVs flies in a close formation and cooperates in their use of jamming resources to prevent being tracked by Surface-to-Air Missile (SAM tracking radars. The main goal of this research effort is develop cooperating UAVs within multi-agent simulation environment. Simulations were generated to test the path planning and control strategies given UAVs/SAM tracking radar network scenarios, and overall UAVs cooperative electronic attack performance in each simulation was analyzed.

  18. Exploring policy options for a transition to sustainable heating system diffusion using an agent-based simulation

    International Nuclear Information System (INIS)

    Change in home heating to more efficient and renewable systems is important for a sound climate policy. The present paper aims to identify potential interventions for the uptake of wood-pellet heating in Norway using an agent-based model (ABM). The theoretically based, empirically founded, agent-based simulation demonstrates that financial support, i.e., a stable wood-pellet price, and technical development, i.e., functional reliability improvement, have to be established all at the same time for a successful wood-pellet market to start. Furthermore, a soft intervention through persuading households to use environmentally beneficial heating system is not a promising driver for wood-pellet diffusion. Limitations and suggestions for future work are also discussed. - Research highlights: → The theoretically based, empirically founded, agent-based simulation is applied to investigate potential policy options toward diffusion of wood-pellet heating in Norway. → Relative advantages are necessary for wood-pellet heating to be adopted, consistent with Diffusion of Innovation theory (). → Simultaneous development is also required for further uptake of wood-pellet heating, supporting the existing empirical hypothesis by . → Persuading households to use environmentally friendly heating system is not a promising driver, in line with empirical finding of , who investigated psychological factors underlying the adoption of wood-pellet heating.

  19. Exploring policy options for a transition to sustainable heating system diffusion using an agent-based simulation

    Energy Technology Data Exchange (ETDEWEB)

    Maya Sopha, Bertha, E-mail: bertha.sopha@ntnu.n [Industrial Ecology Programme and Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Kloeckner, Christian A. [Department of Psychology, Section for Risk Psychology, Environment and Safety (RIPENSA), Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Hertwich, Edgar G. [Industrial Ecology Programme and Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2011-05-15

    Change in home heating to more efficient and renewable systems is important for a sound climate policy. The present paper aims to identify potential interventions for the uptake of wood-pellet heating in Norway using an agent-based model (ABM). The theoretically based, empirically founded, agent-based simulation demonstrates that financial support, i.e., a stable wood-pellet price, and technical development, i.e., functional reliability improvement, have to be established all at the same time for a successful wood-pellet market to start. Furthermore, a soft intervention through persuading households to use environmentally beneficial heating system is not a promising driver for wood-pellet diffusion. Limitations and suggestions for future work are also discussed. - Research highlights: {yields} The theoretically based, empirically founded, agent-based simulation is applied to investigate potential policy options toward diffusion of wood-pellet heating in Norway. {yields} Relative advantages are necessary for wood-pellet heating to be adopted, consistent with Diffusion of Innovation theory (). {yields} Simultaneous development is also required for further uptake of wood-pellet heating, supporting the existing empirical hypothesis by . {yields} Persuading households to use environmentally friendly heating system is not a promising driver, in line with empirical finding of , who investigated psychological factors underlying the adoption of wood-pellet heating.

  20. Adaptive learning in agents behaviour: A framework for electricity markets simulation

    DEFF Research Database (Denmark)

    Pinto, Tiago; Vale, Zita; Sousa, Tiago M.;

    2014-01-01

    decision support to MASCEM's negotiating agents so that they can properly achieve their goals. ALBidS uses artificial intelligence methodologies and data analysis algorithms to provide effective adaptive learning capabilities to such negotiating entities. The main contribution is provided by a methodology...

  1. An Agent-based Simulation of the Effectiveness of Creative Leadership

    CERN Document Server

    Leijnen, Stefan

    2010-01-01

    This paper investigates the effectiveness of creative versus uncreative leadership using EVOC, an agent-based model of cultural evolution. Each iteration, each agent in the artificial society invents a new action, or imitates a neighbor's action. Only the leader's actions can be imitated by all other agents, referred to as followers. Two measures of creativity were used: (1) invention-to-imitation ratio, iLeader, which measures how often an agent invents, and (2) rate of conceptual change, cLeader, which measures how creative an invention is. High iLeader increased mean fitness of ideas, but only when creativity of followers was low. High iLeader was associated with greater diversity of ideas in the early stage of idea generation only. High cLeader increased mean fitness of ideas in the early stage of idea generation; in the later stage it decreased idea fitness. Reasons for these findings and tentative implications for creative leadership in human society are discussed.

  2. On-lattice agent-based simulation of populations of cells within the open-source Chaste framework

    KAUST Repository

    Figueredo, G. P.

    2013-02-21

    Over the years, agent-based models have been developed that combine cell division and reinforced random walks of cells on a regular lattice, reaction-diffusion equations for nutrients and growth factors; and ordinary differential equations for the subcellular networks regulating the cell cycle. When linked to a vascular layer, this multiple scale model framework has been applied to tumour growth and therapy. Here, we report on the creation of an agent-based multi-scale environment amalgamating the characteristics of these models within a Virtual Physiological Human (VPH) Exemplar Project. This project enables reuse, integration, expansion and sharing of the model and relevant data. The agent-based and reaction-diffusion parts of the multi-scale model have been implemented and are available for download as part of the latest public release of Chaste (Cancer, Heart and Soft Tissue Environment; http://www.cs.ox.ac.uk/chaste/), part of the VPH Toolkit (http://toolkit.vph-noe.eu/). The environment functionalities are verified against the original models, in addition to extra validation of all aspects of the code. In this work, we present the details of the implementation of the agent-based environment, including the system description, the conceptual model, the development of the simulation model and the processes of verification and validation of the simulation results. We explore the potential use of the environment by presenting exemplar applications of the \\'what if\\' scenarios that can easily be studied in the environment. These examples relate to tumour growth, cellular competition for resources and tumour responses to hypoxia (low oxygen levels). We conclude our work by summarizing the future steps for the expansion of the current system.

  3. R&D networks and regional knowledge production: an agent-based simulation of the Austrian competence centres programme

    Directory of Open Access Journals (Sweden)

    Manuela Korber

    2014-06-01

    Full Text Available Publicly funded competence centres have gained high recognition for improving science-industry collaboration. With the requirement for long-term and geographically concentrated R&D, competence centres provide an environment for joint learning and transfer of “sticky” knowledge. The objective of this paper is to investigate how a competence centres programme affects knowledge production in the regional innovation system. In order to address this issue, we draw on a simulation approach and develop an agent-based model of the Vienna Life Sciences innovation system. Companies, research organisations and universities are heterogeneous agents that create scientific publications, patents, as well as high-tech jobs. Simulation runs refer to long-term scenarios regarding the level and duration of public funding. By addressing the complexities of knowledge interaction in the context of the “local buzz” versus “global pipelines” discussion, the results show the potential of empirically calibrated simulation models for ex-ante impact assessment in R&D policy.

  4. FDTD assessment of human exposure to electromagnetic fields from WiFi and bluetooth devices in some operating situations.

    Science.gov (United States)

    Martínez-Búrdalo, M; Martín, A; Sanchis, A; Villar, R

    2009-02-01

    In this work, the numerical dosimetry in human exposure to the electromagnetic fields from antennas of wireless devices, such as those of wireless local area networks (WLAN) access points or phone and computer peripherals with Bluetooth antennas, is analyzed with the objective of assessing guidelines compliance. Several geometrical configurations are considered to simulate possible exposure situations of a person to the fields from WLAN or Bluetooth antennas operating at 2400 MHz. The exposure to radiation from two sources of different frequencies when using a 1800 MHz GSM mobile phone connected via Bluetooth with a hands-free car kit is also considered. The finite-difference time-domain (FDTD) method is used to calculate electric and magnetic field values in the vicinity of the antennas and specific absorption rates (SAR) in a high-resolution model of the human head and torso, to be compared with the limits from the guidelines (reference levels and basic restrictions, respectively). Results show that the exposure levels in worst-case situations studied are lower than those obtained when analyzing the exposure to mobile phones, as could be expected because of the low power of the signals and the distance between the human and the antennas, with both field and SAR values being far below the limits established by the guidelines, even when considering the combined exposure to both a GSM and a Bluetooth antenna. PMID:18937345

  5. Grade-2 Teflon (AF1601) PCF for optical communication using 2D FDTD technique: a simplest design

    Science.gov (United States)

    Muduli, N.; Achary, J. S. N.; Padhy, Hemanta ku.

    2016-04-01

    A nonlinear ytterbium-doped rectangular proposed PCF structure of inner and outer cladding is used to analyze effective mode field area (Aeff), nonlinear coefficient (γ), dispersion (D), and confinement loss (CL) in a wide range of wavelength. The fabrication of PCF structure is due to different size doped air hole, pitch, and air hole diameter in a regular periodic geometrical array fashion. The various property of PCF structure such as mode field area, nonlinear coefficient, dispersion, and confinement loss are analyzed by implementing 2D FDTD technique. The above PCF property investigated using suitable parameters like Λ1, ?, ?, and ? in three different situations is discussed in simulation. The high nonlinear coefficient and dispersion property of PCF structure are tailored by setting the cladding parameter. However, highly nonlinear fibers with nonzero dispersion at the wavelength of 1.55 μm are very attractive for a range of optical communication application such as laser amplifier, pulse compression, wavelength conversion, all optical switching, and supercontinuum generation. So our newly proposed ytterbium-doped PCF seems to be most suitable exclusively for supercontinuum generation and nonlinear fiber optics. Finally, it is observed that ytterbium-doped Teflon (AF1601) PCF has more nonlinear coefficient (γ(λ) = 65.27 W-1 km-1) as compared to pure silica PCF (γ(λ) = 52 W-1 km-1) design to have same mode field area (Aeff) 1.7 μm2 at an operating wavelength of 1.55 μm.

  6. A cyclization-induced emission enhancement (CIEE)-based ratiometric fluorogenic and chromogenic probe for the facile detection of a nerve agent simulant DCP.

    Science.gov (United States)

    Mahapatra, Ajit Kumar; Maiti, Kalipada; Manna, Saikat Kumar; Maji, Rajkishor; Mondal, Sanchita; Das Mukhopadhyay, Chitrangada; Sahoo, Prithidipa; Mandal, Debasish

    2015-06-14

    The first ratiometric fluorescent probe for the detection of a nerve agent simulant was developed based on tandem phosphorylation and intramolecular cyclization, by which high sensitivity as well as large emission shift could be achieved. PMID:25980383

  7. New development in Anticipatory Agent System used for Power Management in Smart Home Simulator

    OpenAIRE

    Ahmed Elmahalawy; Mohamed Nour El-Dien

    2012-01-01

    In recent years, there is a global evolution in the way energy is generated and consumed due to climate change, energy independence and the impending decay of fossil fuels. It has seen a rise of interest in the deployment of multi agent systems in energy domains that inherently have uncertain and dynamic environments with limited resources. In such domains, the key challenge is to minimize the energy consumption while satisfying the comfort level of occupants in the buildings under uncertaint...

  8. Representing a Combat ID Analysis Tool within an Agent Based Constructive Simulation

    OpenAIRE

    Dean, D; Mistry, B; Spaans, M.; Vincent, A; Hossain, A

    2009-01-01

    Motivation - This paper describes an approach for the development of a model which represents complex human factors relationships relating to Combat Identification (Combat ID). Research approach - The human factors relationships were incorporated within an experimental Agent Based Model (ABM), using an integrated approach to analysis and experimentation. Research limitations/Implications – This is ongoing work, and is currently limited in application to a single decision maker within a static...

  9. The Dynamics of Emotional Chats with Bots: Experiment and Agent-Based Simulations

    OpenAIRE

    Tadic, Bosiljka; Gligorijevic, Vladimir; Skowron, Marcin; Suvakov, Milovan

    2014-01-01

    Quantitative research of emotions in psychology and machine-learning methods for extracting emotion components from text messages open an avenue for physical science to explore the nature of stochastic processes in which emotions play a role, e.g., in human dynamics online. Here, we investigate the occurrence of collective behavior of users that is induced by chats with emotional Bots. The Bots, designed in an experimental environment, are considered. Furthermore, using the agent-based modeli...

  10. Simulation vs. Definition: Differing Approaches to Setting Probabilities for Agent Behaviour

    OpenAIRE

    Morgan, Fraser J.; Philip Brown; Daigneault, Adam J.

    2015-01-01

    While geographers and economists regularly work together on the development of land-use and land-cover change models, research on how differences in their modelling approaches affects the results is rare. Answering calls for more coordination between the two disciplines in order to build models that better represent the real world, we (two economists and a geographer) developed an economically grounded, spatially explicit, agent-based model to explore the effects of environmental policy on ru...

  11. Identifying bottlenecks in charging infrastructure of plug-in hybrid electric vehicles through agent-based traffic simulation

    OpenAIRE

    Lindgren, Juuso; Lund, Peter D.

    2015-01-01

    The effect of different charging infrastructure configurations on the electric-driven distance of plug-in hybrid electric vehicles (e-mileage) has been investigated, using an agent-based traffic simulation. Our findings suggest that the same e-mileage can be achieved with fewer charging poles if the poles support charging from several parking slots around them, and the charging cable is switched from one vehicle to the next. We also find that the charging power supported by most Finnish charg...

  12. Simulation vs. Definition: Differing Approaches to Setting Probabilities for Agent Behaviour

    Directory of Open Access Journals (Sweden)

    Fraser J. Morgan

    2015-09-01

    Full Text Available While geographers and economists regularly work together on the development of land-use and land-cover change models, research on how differences in their modelling approaches affects the results is rare. Answering calls for more coordination between the two disciplines in order to build models that better represent the real world, we (two economists and a geographer developed an economically grounded, spatially explicit, agent-based model to explore the effects of environmental policy on rural land use in New Zealand. This inter-disciplinary collaboration raised a number of differences in modelling approach. One key difference, and the focus of this paper, is the way in which processes that shape the behaviour of agents are integrated within the model. Using the model and a nationally representative survey, we compare the land-use effects of two disciplinary-aligned approaches to setting a farmer agent’s likelihood of land-use conversion. While we anticipated that the approaches would significantly affect model outcomes, at a catchment scale they produced similar trends and results. However, further analysis at a sub-catchment scale suggests the approach to setting the likelihood of land-use conversion does matter. While the results outlined here will not fully resolve the disciplinary differences, they do outline the need to account for heterogeneity in the predicted agent behaviours for both disciplines.

  13. Modelling, simulation and experimental verification for renewable agents connected to a distorted utility grid using a Real-Time Digital Simulation Platform

    International Nuclear Information System (INIS)

    Highlights: • A MSOGI-FLL is used to detect the frequency. • A PR harmonic-compensator is used. • Grid-connected PV system insensitive to harmonic pollution. • RTDS reinforced the final validation of the control algorithms. • Several algorithms are combined in this paper. - Abstract: The large number of Photovoltaic plants and its utilization as agents of a Distributed Generation Systems justified the increasing efforts towards the optimal design of the overall grid-connected System. In a Distributed Generation environment the low voltage 3-phase utility grid could be affected by some disturbances such as voltage unbalanced, variations of frequency and harmonics distortion and it is mandatory that the control algorithms used in the inverter can be able to maintain the power flow between the renewable agent and the low voltage 3-phase utility grid; in addition a unitary power factor must be attained. A Proportional-Resonant regulator is used to performance a current control with the output current of the inverter and a Multiple Second Order Generalized Integrator Frequency-Locked Loop (MSOGI-FLL) is used to detect the frequency of the low voltage 3-phase utility grid. Some low order harmonics are introduced in the low voltage 3-phase utility grid in order to see the effect of the harmonic compensator. In order to validate the model of the Photovoltaic Renewable agent, the synchronization algorithm and the inverter control algorithm, some simulations using MATLAB/SIMULINK from The MathWorks, Inc. are shown firstly, and secondly, some Real-Time Digital Simulation tests using a Real-Time Digital Simulation (RTDS) Platform are carried out

  14. Secondary ionization of chemical warfare agent simulants: atmospheric pressure ion mobility time-of-flight mass spectrometry.

    Science.gov (United States)

    Steiner, Wes E; Clowers, Brian H; Haigh, Paul E; Hill, Herbert H

    2003-11-15

    For the first time, the use of a traditional ionization source for ion mobility spectrometry (radioactive nickel ((63)Ni) beta emission ionization) and three alternative ionization sources (electrospray ionization (ESI), secondary electrospray ionization (SESI), and electrical discharge (corona) ionization (CI)) were employed with an atmospheric pressure ion mobility orthogonal reflector time-of-flight mass spectrometer (IM(tof)MS) to detect chemical warfare agent (CWA) simulants from both aqueous- and gas-phase samples. For liquid-phase samples, ESI was used as the sample introduction and ionization method. For the secondary ionization (SESI, CI, and traditional (63)Ni ionization) of vapor-phase samples, two modes of sample volatilization (heated capillary and thermal desorption chamber) were investigated. Simulant reference materials, which closely mimic the characteristic chemical structures of CWA as defined and described by Schedule 1, 2, or 3 of the Chemical Warfare Convention treaty verification, were used in this study. A mixture of four G/V-type nerve simulants (dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-(butylamino)ethanethiol) and one S-type vesicant simulant (2-chloroethyl ethyl sulfide) were found in each case (sample ionization and introduction methods) to be clearly resolved using the IM(tof)MS method. In many cases, reduced mobility constants (K(o)) were determined for the first time. Ion mobility drift times, flight times, relative signal intensities, and fragmentation product signatures for each of the CWA simulants are reported for each of the methods investigated. PMID:14615983

  15. Autonomic, Agent-Based Simulation Management (A2SM) Framework Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Large scale numerical simulations, as typified by climate models, space weather models, and the like, typically involve non-linear governing equations in...

  16. Automatic electricity markets data extraction for realistic multi-agent simulations

    DEFF Research Database (Denmark)

    Pereira, Ivo F.; Sousa, Tiago M.; Praca, Isabel;

    2014-01-01

    different market sources, even including different market types; machine learning approach for automatic definition of downloads periodicity of new information available on-line. This is a crucial tool to go a step forward in electricity markets simulation, since the integration of this database with a...... scenarios generation tool, based on knowledge discovery techniques, provides a framework to study real market scenarios allowing simulators improvement and validation....

  17. Artificial Intelligence Rationale for Autonomous Vehicle Agents Behaviour in Driving Simulation Environment

    OpenAIRE

    Charissis, Vassilis; Papanastasiou, Stylianos

    2008-01-01

    This chapter presented the rationale and development process of an open source driving simulator which was exclusively created for the evaluation process of a prototype HUD interface. Financial limitations led to the exploration of new avenues for evaluating the prototype HUD. The simulator hardware was built using off-the-shelf components and the software was developed through customisation of an open source code game engine. For evaluation purposes, equal emphasis was placed on was the deve...

  18. An agent-based framework for fuel cycle simulation with recycling

    International Nuclear Information System (INIS)

    Simulation of the nuclear fuel cycle is an established field with multiple players. Prior development work has utilized techniques such as system dynamics to provide a solution structure for the matching of supply and demand in these simulations. In general, however, simulation infrastructure development has occurred in relatively closed circles, each effort having unique considerations as to the cases which are desired to be modeled. Accordingly, individual simulators tend to have their design decisions driven by specific use cases. Presented in this work is a proposed supply and demand matching algorithm that leverages the techniques of the well-studied field of mathematical programming. A generic approach is achieved by treating facilities as individual entities and actors in the supply-demand market which denote preferences amongst commodities. Using such a framework allows for varying levels of interaction fidelity, ranging from low-fidelity, quick solutions to high-fidelity solutions that model individual transactions (e.g. at the fuel-assembly level). The power of the technique is that it allows such flexibility while still treating the problem in a generic manner, encapsulating simulation engine design decisions in such a way that future simulation requirements can be relatively easily added when needed. (authors)

  19. Understanding coupled natural and human systems on fire prone landscapes: integrating wildfire simulation into an agent based planning system.

    Science.gov (United States)

    Barros, Ana; Ager, Alan; Preisler, Haiganoush; Day, Michelle; Spies, Tom; Bolte, John

    2015-04-01

    Agent-based models (ABM) allow users to examine the long-term effects of agent decisions in complex systems where multiple agents and processes interact. This framework has potential application to study the dynamics of coupled natural and human systems where multiple stimuli determine trajectories over both space and time. We used Envision, a landscape based ABM, to analyze long-term wildfire dynamics in a heterogeneous, multi-owner landscape in Oregon, USA. Landscape dynamics are affected by land management policies, actors decisions, and autonomous processes such as vegetation succession, wildfire, or at a broader scale, climate change. Key questions include: 1) How are landscape dynamics influenced by policies and institutions, and 2) How do land management policies and actor decisions interact to produce intended and unintended consequences with respect to wildfire on fire-prone landscapes. Applying Envision to address these questions required the development of a wildfire module that could accurately simulate wildfires on the heterogeneous landscapes within the study area in terms of replicating historical fire size distribution, spatial distribution and fire intensity. In this paper we describe the development and testing of a mechanistic fire simulation system within Envision and application of the model on a 3.2 million fire prone landscape in central Oregon USA. The core fire spread equations use the Minimum Travel Time algorithm developed by M Finney. The model operates on a daily time step and uses a fire prediction system based on the relationship between energy release component and historical fires. Specifically, daily wildfire probabilities and sizes are generated from statistical analyses of historical fires in relation to daily ERC values. The MTT was coupled with the vegetation dynamics module in Envision to allow communication between the respective subsystem and effectively model fire effects and vegetation dynamics after a wildfire. Canopy and

  20. Spectroscopic investigation of the noncovalent association of the nerve agent simulant diisopropyl methylphosphonate (DIMP) with zinc(II) porphyrins.

    Science.gov (United States)

    Maza, William A; Vetromile, Carissa M; Kim, Chungsik; Xu, Xue; Zhang, X Peter; Larsen, Randy W

    2013-11-01

    Organophosphonates pose a significant threat as chemical warfare agents, as well as environmental toxins in the form of pesticides. Thus, methodologies to sense and decontaminate these agents are of significant interest. Porphyrins and metalloporphyrins offer an excellent platform to develop chemical threat sensors and photochemical degradation systems. These highly conjugated planar molecules exhibit relatively long-lived singlet and triplet states with high quantum yields and also form self-associated complexes with a wide variety of molecules. A significant aspect of porphyrins is the ability to functionalize the peripheral ring system either directly to the pyrrole rings or to the bridging methine carbons. In this report, steady-state absorption and fluorescence are utilized to probe binding affinities of a series of symmetric and asymmetric zinc(II) metalloporphyrins for the nerve agent simulant diisopropyl methylphosphonate (DIMP) in hexane. The red shifts in the absorption and emission spectra observed for all of the metalloporphyrins probed are discussed in the frame of Gouterman's four orbital model and a common binding motif involving coordination between the metalloporphyrin and DIMP via interaction between the zinc metal center of the porphyrin and phosphoryl oxygen of DIMP (Zn-O═P) is proposed. PMID:24093669

  1. Évaluation de la qualité des comportements des agents en simulation : application à un simulateur de conduite en environnement virtuel

    OpenAIRE

    DARTY, Kevin

    2015-01-01

    Cette thèse se situe dans le contexte de la Simulation Multi-Agents et s'intéresse à l'évaluation de la capacité des agents à reproduire individuellement des comportements humains. Les comportements que nous considérons sont dits 'de haut niveau', par opposition aux comportements moteurs ou réflexes. Cette problématique se retrouve dans de nombreux domaines avec la Réalité Virtuelle, les Agents Conversationnels Animés, les agents d'un simulateur immersif, les jeux. L'approche dominante pour é...

  2. Évaluation de la qualité des comportements des agents en simulation : application à un simulateur de conduite en environnement virtuel

    OpenAIRE

    Darty, Kévin

    2015-01-01

    Cette thèse se situe dans le contexte de la Simulation Multi-Agent et s'intéresse à l'évaluation de la capacité des agents à reproduire individuellement des comportements humains. Les comportements que nous considérons sont dits "de haut niveau", par opposition aux comportements moteurs ou réflexes. Cette problématique se retrouve dans de nombreux domaines avec la Réalité Virtuelle, les Agents Conversationnels Animés, les agents d'un simulateur immersif, les jeux. L'approche dominante pour év...

  3. The application of neutral network integrated with genetic algorithm and simulated annealing for the simulation of rare earths separation processes by the solvent extraction technique using EHEHPA agent

    International Nuclear Information System (INIS)

    In the present work, neutral network has been used for mathematically modeling equilibrium data of the mixture of two rare earth elements, namely Nd and Pr with PC88A agent. Thermo-genetic algorithm based on the idea of the genetic algorithm and the simulated annealing algorithm have been used in the training procedure of the neutral networks, giving better result in comparison with the traditional modeling approach. The obtained neutral network modeling the experimental data is further used in the computer program to simulate the solvent extraction process of two elements Nd and Pr. Based on this computer program, various optional schemes for the separation of Nd and Pr have been investigated and proposed. (author)

  4. Simulation of the Role of Government in Spatial Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Viktor Ivanovich Suslov

    2016-09-01

    Full Text Available The paper describes the further development of an agent-based multiregional input-output model of the Russian economy. We consider the idea of incorporating the government into the model and analyze the results of experimental calculations for the conditional example of spatial economy. New agents are included into the model such as the federal and regional governments, pension fund and also the state enterprises producing public goods at the federal and regional levels. The government sets four types of taxes (personal and business income taxes, VAT and payroll taxes, ensures the provision of public goods and provides social, investment and interbudgetary transfers to households, firms and budgets. Social transfers consist of social assistance and unemployment benefits. The utility functions of households are expanded by the terms associated with national and regional public goods. The budget policy is designed in accordance with the maximization of isoelastic function of social welfare that formalizes the choice between the different concepts of social justice. The Gini index is used for the monitoring the inequality of income distribution. The results of experimental calculations present the convergence of the new version of the model to the state of quasi-equilibrium. The special attention is paid an optimal level of the taxation maximizing the social welfare function. Four variants of the optimal tax rates are defined: for three major taxes at a fixed proportion of rates and for each of the tax separately at zero rates of two other taxes. The further directions of modelling are identified, they allow to investigate the spatial development of the Russian economy taking into account the decision-making by private agents in responding to government policies.

  5. Applying System Dynamics and Agent-based Modelling in Archaeological Simulation

    Czech Academy of Sciences Publication Activity Database

    Olševičová, K.; Danielisová, Alžběta

    Olomouc : Palacký University, 2014 - (Talašová, J.; Stoklasa, J.; Talášek, T.), s. 721-726 ISBN 978-80-244-4209-9. [MME 2014. International Conference Mathematical Methods in Economics /32./. Olomouc (CZ), 10.09.2014-12.09.2014] R&D Projects: GA ČR GAP405/12/0926 Institutional support: RVO:67985912 Keywords : agent-based model * cellular automata * land use model * NetLogo * sustainability * system dynamics Subject RIV: AC - Archeology, Anthropology, Ethnology

  6. Mathematical Simulation of the Extraction of a Blending Agent from Cylindrical Bodies in the Semicontinuous Regime

    Science.gov (United States)

    Rudobashta, S. P.; Kosheleva, M. K.; Kartashov, É. M.

    2016-06-01

    A problem of the kinetics of extraction of a blending agent from cylindrical bodies in an apparatus of semicontinuous action (periodic for the solid phase and continuous for the liquid phase) in which the liquid phase is completely mixed was formulated and solved analytically. The kinetics of the indicated process at different specific flow rates of the liquid phase was analyzed with the use of a numerical method. Recommendations on the use of the solution obtained for calculating the kinetics of extraction of technological contaminants from textile materials in the process of their flushing are given

  7. 基于Repast的多Agent建模方法仿真实现研究%Research on Simulation Achievement of Multi-Agent Modeling Method Based on Repast

    Institute of Scientific and Technical Information of China (English)

    郭超; 陈勇

    2012-01-01

    Multi-Agent modeling is an effective method to study a complex system, and multi-A-gent simulation platforms provide favorable conditions to application of this method. Repast is a typical representative of multi-Agent simulation platforms. In this paper, firstly the conception of multi-Agent modeling is introduced briefly, and then Repast is introduced in the terms of composing of simulation models and achievement of simulation programs, and finally the method to design implement a simulation program is demonstrated further by a military operation example. It will provide guidance to starting multi-Agent simulation tasks.%多Agent建模方法是研究复杂系统的有效方法,而多Agent仿真平台为其应用提供了有利条件,Repast(recursive porous agent simulation toolkit)是多Agent仿真平台的典型代表.首先简要介绍了多Agent建模方法的思想;然后从仿真模型的组成和仿真程序的实现2个方面介绍了Repast仿真平台;最后通过一个军事模拟实例进一步说明了Repast仿真程序的设计与实现方法,对于使用Repast开展多Agent系统仿真工作具有一定指导意义.

  8. Active Power Control Simulation Platform Research of Wind Farm Based on Multi-Agent

    Directory of Open Access Journals (Sweden)

    Liu Xingjie

    2015-01-01

    Full Text Available The realization of the automation, routinization and intelligentization of dispatch control in wind farms is the key to the integration of wind farms into power grid management system. Active power regulate and control system in wind farms has increasingly high demand on timeliness, but at present this system is mostly equipped with centralized unidirectional control with poor timeliness and low utilization ratio for wind energy resources. The characteristics of distribution and instantaneity owned by the active power regulate and control system in wind farms are highly consistent with Multi-Agent system. This paper discusses a kind of processing method that is used in real-time, distributed and parallel computation and processing for multiple simultaneously running wind turbines, which is based on Multi-Agent technology and adopting JADE development platform. This method converts massive centralized computation to distributed computation, which optimizes the effect of the power control. This method makes the effectiveness of active power regulate and control system better, wins time for timely allocating electricity generation assignments and dealing with problems, and avoids the heavy loss of resources.

  9. Analysis of microstrip dipoles and slots transversely coupled to a microstrip line using the FDTD method

    Science.gov (United States)

    Tulintseff, A. N.

    1993-01-01

    Printed dipole elements and their complement, linear slots, are elementary radiators that have found use in low-profile antenna arrays. Low-profile antenna arrays, in addition to their small size and low weight characteristics, offer the potential advantage of low-cost, high-volume production with easy integration with active integrated circuit components. The design of such arrays requires that the radiation and impedance characteristics of the radiating elements be known. The FDTD (Finite-Difference Time-Domain) method is a general, straight-forward implementation of Maxwell's equations and offers a relatively simple way of analyzing both printed dipole and slot elements. Investigated in this work is the application of the FDTD method to the analysis of printed dipole and slot elements transversely coupled to an infinite transmission line in a multilayered configuration. Such dipole and slot elements may be used in dipole and slot series-fed-type linear arrays, where element offsets and interelement line lengths are used to obtain the desired amplitude distribution and beam direction, respectively. The design of such arrays is achieved using transmission line theory with equivalent circuit models for the radiating elements. In an equivalent circuit model, the dipole represents a shunt impedance to the transmission line, where the impedance is a function of dipole offset, length, and width. Similarly, the slot represents a series impedance to the transmission line. The FDTD method is applied to single dipole and slot elements transversely coupled to an infinite microstrip line using a fixed rectangular grid with Mur's second order absorbing boundary conditions. Frequency-dependent circuit and scattering parameters are obtained by saving desired time-domain quantities and using the Fourier transform. A Gaussian pulse excitation is applied to the microstrip transmission line, where the resulting reflected signal due to the presence of the radiating element is used

  10. An integrated neural-symbolic cognitive agent architecture for training and assessment in simulators

    NARCIS (Netherlands)

    Penning, H.L.H. de; d'Avila Garcez, A.S.; Lamb, L.C.; Meyer, J.J.C.

    2010-01-01

    Training and assessment of complex tasks has always been a complex task in itself. Training simulators can be used for training and assessment of low-order skills. High-order skills (e.g. safe driving, leadership, tactical manoeuvring, etc.) are generally trained and assessed by human experts, due t

  11. Optical detection of chemical warfare agents and toxic industrial chemicals: Simulation

    Science.gov (United States)

    Webber, Michael E.; Pushkarsky, Michael; Patel, C. Kumar N.

    2005-06-01

    We present an analysis of optical techniques for the detection of chemical warfare agents and toxic industrial chemicals in real-world conditions. We analyze the problem of detecting a target species in the presence of a multitude of interferences that are often stochastic and we provide a broadly applicable technique for evaluating the sensitivity, probability of false positives (PFP), and probability of false negatives (PFN) for a sensor through the illustrative example of a laser photoacoustic spectrometer (L-PAS). This methodology includes (1) a model of real-world air composition, (2) an analytical model of an actual field-deployed L-PAS, (3) stochasticity in instrument response and air composition, (4) repeated detection calculations to obtain statistics and receiver operating characteristic curves, and (5) analyzing these statistics to determine the sensor's sensitivity, PFP, and PFN. This methodology was used to analyze variations in sensor design and ambient conditions, and can be utilized as a framework for comparing different sensors.

  12. Investigation of composite electromagnetic scattering from ship-like target on the randomly rough sea surface using FDTD method

    International Nuclear Information System (INIS)

    Composite electromagnetic scattering from a two-dimensional (2D) ship-like target on a one-dimensional sea surface is investigated by using the finite-difference time-domain (FDTD) method. A uniaxial perfectly matched layer is adopted for truncation of FDTD lattices. The FDTD updated equations can be used for the total computation domain by choosing the uniaxial parameters properly. To validate the proposed numerical technique, a 2D infinitely long cylinder over the sea surface is taken into account first. The variation of angular distribution of the scattering changing with incident angle is calculated. The results show good agreement with the conventional moment method. Finally, the influence of the incident angle, the polarization, and the size of the ship-like target on the composite scattering coefficient is discussed in detail. (classical areas of phenomenology)

  13. An Approach for Simulating Soil Loss from an Agro-Ecosystem Using Multi-Agent Simulation: A Case Study for Semi-Arid Ghana

    Directory of Open Access Journals (Sweden)

    Biola K. Badmos

    2015-07-01

    Full Text Available Soil loss is not limited to change from forest or woodland to other land uses/covers. It may occur when there is agricultural land-use/cover modification or conversion. Soil loss may influence loss of carbon from the soil, hence implication on greenhouse gas emission. Changing land use could be considered actually or potentially successful in adapting to climate change, or may be considered maladaptation if it creates environmental degradation. In semi-arid northern Ghana, changing agricultural practices have been identified amongst other climate variability and climate change adaptation measures. Similarly, some of the policies aimed at improving farm household resilience toward climate change impact might necessitate land use change. The heterogeneity of farm household (agents cannot be ignored when addressing land use/cover change issues, especially when livelihood is dependent on land. This paper therefore presents an approach for simulating soil loss from an agro-ecosystem using multi-agent simulation (MAS. We adapted a universal soil loss equation as a soil loss sub-model in the Vea-LUDAS model (a MAS model. Furthermore, for a 20-year simulation period, we presented the impact of agricultural land-use adaptation strategy (maize cultivation credit i.e., maize credit scenario on soil loss and compared it with the baseline scenario i.e., business-as-usual. Adoption of maize as influenced by maize cultivation credit significantly influenced agricultural land-use change in the study area. Although there was no significant difference in the soil loss under the tested scenarios, the incorporation of human decision-making in a temporal manner allowed us to view patterns that cannot be seen in single step modeling. The study shows that opening up cropland on soil with a high erosion risk has implications for soil loss. Hence, effective measures should be put in place to prevent the opening up of lands that have high erosion risk.

  14. Final report for the endowment of simulator agents with human-like episodic memory LDRD.

    Energy Technology Data Exchange (ETDEWEB)

    Speed, Ann Elizabeth; Lippitt, Carl Edward; Thomas, Edward Victor; Xavier, Patrick Gordon; Forsythe, Christi A.; Schaller, Mark J.; Schoenwald, David Alan

    2003-12-01

    This report documents work undertaken to endow the cognitive framework currently under development at Sandia National Laboratories with a human-like memory for specific life episodes. Capabilities have been demonstrated within the context of three separate problem areas. The first year of the project developed a capability whereby simulated robots were able to utilize a record of shared experience to perform surveillance of a building to detect a source of smoke. The second year focused on simulations of social interactions providing a queriable record of interactions such that a time series of events could be constructed and reconstructed. The third year addressed tools to promote desktop productivity, creating a capability to query episodic logs in real time allowing the model of a user to build on itself based on observations of the user's behavior.

  15. An Empirically grounded Agent Based simulator for the Air Traffic Management in the SESAR scenario

    CERN Document Server

    Gurtner, Gérald; Ducci, Marco; Miccichè, Salvatore

    2016-01-01

    In this paper we present a simulator allowing to perform policy experiments relative to the air traffic management. Different SESAR solutions can be implemented in the model to see the reaction of the different stakeholders as well as other relevant metrics (delays, safety, etc). The model describes both the strategic phase associated to the planning of the flight trajectories and the tactical modifications occurring in the en-route phase. An implementation of the model is available as open-source and freely accessible by any user. More specifically, different procedures related to business trajectories and free-routing are tested and we illustrate the capabilities of the model on airspace implementing these concepts. After performing numerical simulations with the model, we show that in a free-routing scenario the controllers perform less operations although they are dispersed over a larger portion of the airspace. This can potentially increase the complexity of conflict detection and resolution for controll...

  16. Developing an Agent-Based Model to Simulate Urban Land-Use Expansion (Case Study: Qazvin)

    OpenAIRE

    F. Nourian; A. A. Alesheikh; F. Hosseinali

    2012-01-01

    Extended abstract1-IntroductionUrban land-use expansion is a challenging issue in developing countries. Increases in population as well as the immigration from the villages to the cities are the two major factors for that phenomenon. Those factors have reduced the influence of efforts that try to limit the cities’ boundaries. Thus, spatial planners always look for the models that simulate the expansion of urban land-uses and enable them to prevent unbalanced expansions of cities and guide the...

  17. Six thinking hats for electricity markets simulation: adapting meeting tools to agent decision

    OpenAIRE

    Barreto, João Costa Borges

    2012-01-01

    In almost all industrialized countries, the energy sector has suffered a severe restructuring that originated a greater complexity in market players’ interactions. The complexity that these changes brought made way for the creation of decision support tools that facilitate the study and understanding of these markets. MASCEM – “Multiagent Simulator for Competitive Electricity Markets” arose in this context providing a framework for evaluating new rules, new behaviour, and new participants ...

  18. SIMULATION A DYNAMIC MODELING THEORY OF STEAM TURBINE BASED ON AGENTIC A LOGARITHM

    OpenAIRE

    Shaker,, Olfat

    2015-01-01

    In the present paper, a thermodynamic analysis of steam turbine type (K–800–23.5–0.034), power plant has been carried out. The power plant system was simulated and a detailed parametric study undertaken, which involved environmental parameters, such as the temperature of cooling water entering the condenser and the inlet ambient air temperature, as well as some other operational parameters, such as excess air percentage and stack exhaust temperature. It was noted that the excess a...

  19. Simulation of Artificial Intelligence Agents using Modelica and the DLR Visualization Library

    OpenAIRE

    Schaub, Alexander; Hellerer, Matthias; Bodenmüller, Tim

    2012-01-01

    This paper introduces a scheme for testing artificial intelligence algorithms of autonomous systems using Modelica and the DLR Visualization Library. The simulation concept follows the ’Software-in-the-loop’ principle, whereas no adaptations are made to the tested algorithms. The environment is replaced by an artificial world and the rest of the autonomous system is modeled in Modelica. The scheme is introduced and explained by using the example of the ROboMObil, wh...

  20. Simulation of Past Life: Controlling Agent Behaviors from the Interactions between Ethnic Groups

    OpenAIRE

    Lim, Chen Kim; Cani, Marie-Paule; Galvane, Quentin; Pettre, Julien; Talib, Abdullah Zawawi

    2013-01-01

    International audience Many efforts have been carried out in preserving the history and culture of Penang and also other regions of Malaysia since George Town was elected as a UNESCO living heritage city. This paper presents a method to simulate life in a local trading port in the 1800s, where various populations with very different social rules interacted with each other. These populations included Indian coolies, Malay vendors, British colonists and Chinese traders. The challenge is to m...

  1. Agent-Based Simulations of Malaria Transmissions with Applications to a Study Site in Thailand

    Science.gov (United States)

    Kiang, Richard K.; Adimi, Farida; Zollner, Gabriela E.; Coleman, Russell E.

    2006-01-01

    The dynamics of malaria transmission are driven by environmental, biotic and socioeconomic factors. Because of the geographic dependency of these factors and the complex interactions among them, it is difficult to generalize the key factors that perpetuate or intensify malaria transmission. Methods: Discrete event simulations were used for modeling the detailed interactions among the vector life cycle, sporogonic cycle and human infection cycle, under the explicit influences of selected extrinsic and intrinsic factors. Meteorological and environmental parameters may be derived from satellite data. The output of the model includes the individual infection status and the quantities normally observed in field studies, such as mosquito biting rates, sporozoite infection rates, gametocyte prevalence and incidence. Results were compared with mosquito vector and human malaria data acquired over 4.5 years (June 1999 - January 2004) in Kong Mong Tha, a remote village in Kanchanaburi Province, western Thailand. Results: Three years of transmissions of vivax and falciparum malaria were simulated for a hypothetical hamlet with approximately 1/7 of the study site population. The model generated results for a number of scenarios, including applications of larvicide and insecticide, asymptomatic cases receiving or not receiving treatment, blocking malaria transmission in mosquito vectors, and increasing the density of farm (host) animals in the hamlet. Transmission characteristics and trends in the simulated results are comparable to actual data collected at the study site.

  2. Modelling and Simulating of Risk Behaviours in Virtual Environments Based on Multi-Agent and Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Linqin Cai

    2013-11-01

    Full Text Available Due to safety and ethical issues, traditional experimental approaches to modelling underground risk behaviours can be costly, dangerous and even impossible to realize. Based on multi-agent technology, a virtual coalmine platform for risk behaviour simulation is presented to model and simulate the human-machine- environment related risk factors in underground coalmines. To reveal mine workers’ risk behaviours, a fuzzy emotional behaviour model is proposed to simulate underground miners’ responding behaviours to potential hazardous events based on cognitive appraisal theories and fuzzy logic techniques. The proposed emotion model can generate more believable behaviours for virtual miners according to personalized emotion states, internal motivation needs and behaviour selection thresholds. Finally, typical accident cases of underground hazard spotting and locomotive transport were implemented. The behaviour believability of virtual miners was evaluated with a user assessment method. Experimental results show that the proposed models can create more realistic and reasonable behaviours in virtual coalmine environments, which can improve miners’ risk awareness and further train miners’ emergent decision-making ability when facing unexpected underground situations.

  3. Decomposition kinetics of dimethyl methylphospate(chemical agent simulant) by supercritical water oxidation

    Institute of Scientific and Technical Information of China (English)

    Bambang VERIANSYAH; Jae-Duck KIM; Youn-Woo LEE

    2006-01-01

    Supercritical water oxidation (SCWO) has been drawing much attention due to effectively destroy a large variety of high-risk wastes resulting from munitions demilitarization and complex industrial chemical. An important design consideration in the development of supercritical water oxidation is the information of decomposition rate. In this paper, the decomposition rate of dimethyl methylphosphonate(DMMP), which is similar to the nerve agent VX and GB(Sarin) in its structure, was investigated under SCWO conditions. The experiments were performed in an isothermal tubular reactor with a H2O2 as an oxidant. The reaction temperatures were ranged from 398 to 633 ℃ at a fixed pressure of 24 MPa. The conversion of DMMP was monitored by analyzing total organic carbon (TOC) on the liquid effluent samples. It is found that the oxidative decomposition of DMMP proceeded rapidly and a high TOC decomposition up to 99.99% was obtained within 11 s at 555℃. On the basis of data derived from experiments, a global kinetic equation for the decomposition of DMMP was developed. The model predictions agreed well with the experimental data.

  4. Application of Cross-correlation Greens Function along with FDTD for Fast Computation of Envelope Correlation Coefficient over Wideband for MIMO Antennas

    CERN Document Server

    Sarkar, Debdeep

    2016-01-01

    In this paper, the concept of cross-correlation Green's functions (CGF) is used in conjunction with the finite difference time domain (FDTD) technique for calculation of envelope correlation coefficient (ECC) of any arbitrary MIMO antenna system over wide frequency band. Both frequency-domain (FD) and time-domain (TD) post-processing techniques are proposed for possible application with this FDTD-CGF scheme. The FDTD-CGF time-domain (FDTD-CGF-TD) scheme utilizes time-domain signal processing methods and exhibits significant reduction in ECC computation time as compared to the FDTD-CGF frequency domain (FDTD-CGF-FD) scheme, for high frequency-resolution requirements. The proposed FDTD-CGF based schemes can be applied for accurate and fast prediction of wideband ECC response, instead of the conventional scattering parameter based techniques which have several limitations. Numerical examples of the proposed FDTD-CGF techniques are provided for two-element MIMO systems involving thin-wire half-wavelength dipoles ...

  5. Development Of An Agent Based Simulation For The Cellular Transport System And Scenario Based Performance Analysis

    Directory of Open Access Journals (Sweden)

    Elif Karakaya

    2016-01-01

    Full Text Available Intralogistics Systems, in the rapidly increasing global business environment, are becoming more complex to analyze and more challenging to manage. In order to achieve the highest possible performance of warehouse operations, demanded by today’s modern businesses, intralogistics systems should be agile and flexible. With this objective in mind, the Cellular Transport System (CTS was developed as an alternative intralogistics system by Fraunhofer Institute for Material Flow and Logistics. This study investigates novel intralogistics system, the CTS, and proposes an integrated simulation tool in order to systematically anticipate change drivers and take optimum measures for the CTS.

  6. The Virtual Anatomy Lab: an eDemonstrator pedagogical agent can simulate student-faculty interaction and promote student engagement

    Directory of Open Access Journals (Sweden)

    Jonathan Weber

    2012-07-01

    Full Text Available As medical curricula evolve, many universities have adopted a clinical case-centered medical curriculum with a strong focus on small group learning and reduction of traditional lectures such that anatomy has become a self-taught subject supported by e-learning modules. One caveat of this approach is decreased student-faculty interaction and reduced student engagement. Thus use of e-learning must be balanced with the need for continued student-faculty interaction to promote healthy student engagement. To both support self-directed learning of anatomy and to simulate student-faculty interaction, we created the Virtual Anatomy Lab (VAL that features a human pedagogical agent, called the eDemonstrator, who guides student navigation through the available learning resources. The VAL was evaluated using a mixed methods approach (usage statistics and focus groups by two medical student populations at the University of Ottawa: first year medical students in a revised curriculum where anatomy lectures were abolished and laboratory sessions were self-taught, and second year medical students in the former curriculum in which anatomy lectures were given in advance of each laboratory session. We conclude that online modules such as the VAL, well designed with a human pedagogical agent, can be used within the curriculum without negatively impacting student engagement. Ethical Approval for this study was obtained from the Ottawa Hospital Research Ethics Board (protocol number #2009055-01H.

  7. Transport behavior of surrogate biological warfare agents in a simulated landfill: Effect of leachate recirculation and water infiltration

    KAUST Repository

    Saikaly, Pascal

    2010-11-15

    An understanding of the transport behavior of biological warfare (BW) agents in landfills is required to evaluate the suitability of landfills for the disposal of building decontamination residue (BDR) following a bioterrorist attack on a building. Surrogate BW agents, Bacillus atrophaeus spores and Serratia marcescens, were spiked into simulated landfill reactors that were filled with synthetic building debris (SBD) and operated for 4 months with leachate recirculation or water infiltration. Quantitative polymerase chain reaction (Q-PCR) was used to monitor surrogate transport. In the leachate recirculation reactors, <10% of spiked surrogates were eluted in leachate over 4 months. In contrast, 45% and 31% of spiked S. marcescens and B. atrophaeus spores were eluted in leachate in the water infiltration reactors. At the termination of the experiment, the number of retained cells and spores in SBD was measured over the depth of the reactor. Less than 3% of the total spiked S. marcescens cells and no B. atrophaeus spores were detected in SBD. These results suggest that significant fractions of the spiked surrogates were strongly attached to SBD. © 2010 American Chemical Society.

  8. An integrated ant colony optimization approach to compare strategies of clearing market in electricity markets: Agent-based simulation

    International Nuclear Information System (INIS)

    In this paper, an innovative model of agent based simulation, based on Ant Colony Optimization (ACO) algorithm is proposed in order to compare three available strategies of clearing wholesale electricity markets, i.e. uniform, pay-as-bid, and generalized Vickrey rules. The supply side actors of the power market are modeled as adaptive agents who learn how to bid strategically to optimize their profit through indirect interaction with other actors of the market. The proposed model is proper for bidding functions with high number of dimensions and enables modelers to avoid curse of dimensionality as dimension grows. Test systems are then used to study the behavior of each pricing rule under different degrees of competition and heterogeneity. Finally, the pricing rules are comprehensively compared using different economic criteria such as average cleared price, efficiency of allocation, and price volatility. Also, principle component analysis (PCA) is used to rank and select the best price rule. To the knowledge of the authors, this is the first study that uses ACO for assessing strategies of wholesale electricity market.

  9. Interaction of collagen with chlorosulphonated paraffin tanning agents: Fourier transform infrared spectroscopic analysis and molecular dynamics simulations.

    Science.gov (United States)

    Monti, Susanna; Bramanti, Emilia; Della Porta, Valentina; Onor, Massimo; D'Ulivo, Alessandro; Barone, Vincenzo

    2013-09-21

    The binding of chlorosulphonated paraffins to collagen triple helices is studied by means of classical molecular dynamics simulations and experimental spectroscopic techniques in order to disclose the principal characteristics of their interaction during the leather fattening process. Indeed, collagen is the main target to develop new leather modifying agents with specific characteristics, and an accurate design of the collagen binders, supported by predictive computational strategies, could be a successful tool to obtain new effective eco-compatible compounds able to impart to the leather the required functionalities and distinctive mechanical properties. Possible effects caused by the tanning agents on the collagen matrix have been identified from both experimental and theoretical points of view. Computational data in agreement with experiment have revealed that chlorosulphonated paraffins can interact favorably with the collagen residues having amine groups in their side chains (Arg, Lys, Asn and Gln) and reduce the tendency of the solvated collagen matrix to swell. However, the interference of chlorosulphonated paraffins with the unfolding process, which is operated mainly by the action of water, can be due both to covalent cross-linking of the collagen chains and intermolecular hydrogen bonding interactions involving also the hydroxyl groups of Hyp, Ser and Thr residues. PMID:23904010

  10. An integrated ant colony optimization approach to compare strategies of clearing market in electricity markets: Agent-based simulation

    Energy Technology Data Exchange (ETDEWEB)

    Azadeh, A., E-mail: aazadeh@ut.ac.i [Department of Industrial Engineering and Center of Excellence for Intelligent Experimental Mechanics, College of Engineering, University of Tehran (Iran, Islamic Republic of); Skandari, M.R. [Department of Industrial Engineering, University of Florida, Gainesville (United States); Maleki-Shoja, B. [Department of Industrial Engineering and Center of Excellence for Intelligent Experimental Mechanics, College of Engineering, University of Tehran (Iran, Islamic Republic of)

    2010-10-15

    In this paper, an innovative model of agent based simulation, based on Ant Colony Optimization (ACO) algorithm is proposed in order to compare three available strategies of clearing wholesale electricity markets, i.e. uniform, pay-as-bid, and generalized Vickrey rules. The supply side actors of the power market are modeled as adaptive agents who learn how to bid strategically to optimize their profit through indirect interaction with other actors of the market. The proposed model is proper for bidding functions with high number of dimensions and enables modelers to avoid curse of dimensionality as dimension grows. Test systems are then used to study the behavior of each pricing rule under different degrees of competition and heterogeneity. Finally, the pricing rules are comprehensively compared using different economic criteria such as average cleared price, efficiency of allocation, and price volatility. Also, principle component analysis (PCA) is used to rank and select the best price rule. To the knowledge of the authors, this is the first study that uses ACO for assessing strategies of wholesale electricity market.

  11. An integrated ant colony optimization approach to compare strategies of clearing market in electricity markets. Agent-based simulation

    International Nuclear Information System (INIS)

    In this paper, an innovative model of agent based simulation, based on Ant Colony Optimization (ACO) algorithm is proposed in order to compare three available strategies of clearing wholesale electricity markets, i.e. uniform, pay-as-bid, and generalized Vickrey rules. The supply side actors of the power market are modeled as adaptive agents who learn how to bid strategically to optimize their profit through indirect interaction with other actors of the market. The proposed model is proper for bidding functions with high number of dimensions and enables modelers to avoid curse of dimensionality as dimension grows. Test systems are then used to study the behavior of each pricing rule under different degrees of competition and heterogeneity. Finally, the pricing rules are comprehensively compared using different economic criteria such as average cleared price, efficiency of allocation, and price volatility. Also, principle component analysis (PCA) is used to rank and select the best price rule. To the knowledge of the authors, this is the first study that uses ACO for assessing strategies of wholesale electricity market. (author)

  12. An integrated ant colony optimization approach to compare strategies of clearing market in electricity markets. Agent-based simulation

    Energy Technology Data Exchange (ETDEWEB)

    Azadeh, A.; Maleki-Shoja, B. [Department of Industrial Engineering and Center of Excellence for Intelligent Experimental Mechanics, College of Engineering, University of Tehran (Iran); Skandari, M.R. [Department of Industrial Engineering, University of Florida, Gainesville (United States)

    2010-10-15

    In this paper, an innovative model of agent based simulation, based on Ant Colony Optimization (ACO) algorithm is proposed in order to compare three available strategies of clearing wholesale electricity markets, i.e. uniform, pay-as-bid, and generalized Vickrey rules. The supply side actors of the power market are modeled as adaptive agents who learn how to bid strategically to optimize their profit through indirect interaction with other actors of the market. The proposed model is proper for bidding functions with high number of dimensions and enables modelers to avoid curse of dimensionality as dimension grows. Test systems are then used to study the behavior of each pricing rule under different degrees of competition and heterogeneity. Finally, the pricing rules are comprehensively compared using different economic criteria such as average cleared price, efficiency of allocation, and price volatility. Also, principle component analysis (PCA) is used to rank and select the best price rule. To the knowledge of the authors, this is the first study that uses ACO for assessing strategies of wholesale electricity market. (author)

  13. Simulation,construction and characterization of a multi-functional thrombolytic agent with anti-thrombosis activity

    Institute of Scientific and Technical Information of China (English)

    Weiran YU; Jian JING

    2008-01-01

    Prourokinase (scu-PA),a thrombolytic agent,was inserted between Glyl 18 and Ilel 19 with foreign anti-thrombosis functional motif (Lys-Gly-Asp-Trp-motif) to construct a multi-functional chimeric molecule.The molecular model of a chimera was simulated and pre-dicted.The recombinant chimeric protein was expressed by the baculovirus-insect cell expression system and puri-fied by affinity chromatography.The physico-chemical characteristics of the chimeric molecule were assayed.The thrombolytic activity was determined to be 90000 IU/mg of fibrinolytic special activity by the fibrin-plate method.The anti-thrombosis activities were also assayed with IC50 of 9.6 μM by an inhibition test of ADP-induced platelet aggregation.

  14. 4D-SAS: A Distributed Dynamic-Data Driven Simulation and Analysis System for Massive Spatial Agent-Based Modeling

    Directory of Open Access Journals (Sweden)

    Zhenqiang Li

    2016-03-01

    Full Text Available Significant computation challenges are emerging as agent-based modeling becomes more complicated and dynamically data-driven. In this context, parallel simulation is an attractive solution when dealing with massive data and computation requirements. Nearly all the available distributed simulation systems, however, do not support geospatial phenomena modeling, dynamic data injection, and real-time visualization. To tackle these problems, we propose a distributed dynamic-data driven simulation and analysis system (4D-SAS specifically for massive spatial agent-based modeling to support real-time representation and analysis of geospatial phenomena. To accomplish large-scale geospatial problem-solving, the 4D-SAS system was spatially enabled to support geospatial model development and employs high-performance computing to improve simulation performance. It can automatically decompose simulation tasks and distribute them among computing nodes following two common schemes: order division or spatial decomposition. Moreover, it provides streaming channels and a storage database to incorporate dynamic data into simulation models; updating agent context in real-time. A new online visualization module was developed based on a GIS mapping library, SharpMap, for an animated display of model execution to help clients understand the model outputs efficiently. To evaluate the system’s efficiency and scalability, two different spatially explicitly agent-based models, an en-route choice model, and a forest fire propagation model, were created on 4D-SAS. Simulation results illustrate that 4D-SAS provides an efficient platform for dynamic data-driven geospatial modeling, e.g., both discrete multi-agent simulation and grid-based cellular automata, demonstrating efficient support for massive parallel simulation. The parallel efficiency of the two models is above 0.7 and remains nearly stable in our experiments.

  15. Biochemical characterization and molecular dynamic simulation of β-sitosterol as a tubulin-binding anticancer agent.

    Science.gov (United States)

    Mahaddalkar, Tejashree; Suri, Charu; Naik, Pradeep Kumar; Lopus, Manu

    2015-08-01

    Βeta-sitosterol (β-SITO), a phytosterol present in pomegranate, peanut, corn oil, almond, and avocado, has been recognized to offer health benefits and potential clinical uses. β-SITO is orally bioavailable and, as a constituent of edible natural products, is considered to have no undesired side effects. It has also been considered as a potent anticancer agent. However, the molecular mechanism of action of β-SITO as a tubulin-binding anticancer agent and its binding site on tubulin are poorly understood. Using a combination of biochemical analyses and molecular dynamic simulation, we investigated the molecular details of the binding interactions of β-SITO with tubulin. A polymer mass assay comparing the effects of β-SITO and of taxol and vinblastine on tubulin assembly showed that this phytosterol stabilized microtubule assembly in a manner similar to taxol. An 8-anilino-1-naphthalenesulfonic acid assay confirmed the direct interaction of β-SITO with tubulin. Although β-SITO did not show direct binding to the colchicine site on tubulin, it stabilized the colchicine binding. Interestingly, no sulfhydryl groups of tubulin were involved in the binding interaction of β-SITO with tubulin. Based on the results from the biochemical assays, we computationally modeled the binding of β-SITO with tubulin. Using molecular docking followed by molecular dynamic simulations, we found that β-SITO binds tubulin at a novel site (which we call the 'SITO site') adjacent to the colchicine and noscapine sites. Our data suggest that β-SITO is a potent anticancer compound that interferes with microtubule assembly dynamics by binding to a novel site on tubulin. PMID:25912799

  16. 基于Agent的复杂系统建模与仿真研究%Research on Agent-based modeling and simulation of complex system

    Institute of Scientific and Technical Information of China (English)

    王亚康; 郭晶; 江汀; 柴新代

    2011-01-01

    Agent-based modeling and simulation provides new ways to research Complex System, inaugurate a new realm of Complex System modeling and simulation compared to traditional modeling methods. The process of complex system modeling is analyzed firsfiy based on agent in the paper, the authors take the aerial defense combat command system of warship fleet for example, then design the model structure of simulation agent entities, and HLA/RTI could be used as the support environment of multi-agent based simulation environment. Based on the work done, the logic architecture and simulation flow are presented for system simulation based on agent. The study of this thesis provides reference for complex system modehng and simulation based on agent in the future.%基于Agent建模与仿真克服了传统的建模技术存在的不足,为复杂系统研究提供了新的思路.在基于Agent的复杂系统建模方法分析的基础上,结合信息对抗环境下护航舰艇编队防空作战系统实例,设计了各个仿真Agent实体的模型结构,采用HLA/RTI作为多Agent仿真环境的支撑环境,在此基础上给出了系统仿真的逻辑结构和仿真流程.该研究为基于Agent建模与仿真的复杂系统研究提供了参考.

  17. Concepts and theoretical specifications of a Coastal Vulnerability Dynamic Simulator (COVUDS): A multi-agent system for simulating coastal vulnerability towards management of coastal ecosystem services

    Science.gov (United States)

    Orencio, P. M.; Endo, A.; Taniguchi, M.

    2014-12-01

    Disaster-causing natural hazards such as floods, erosions, earthquakes or slope failures were particularly observed to be concentrated in certain geographical regions. In the Asia-pacific region, coastal ecosystems were suffering because of perennial threats driven by chronic fluctuations in climate variability (e.g., typhoons, ENSO), or by dynamically occurring events (e.g., earthquakes, tsunamis). Among the many people that were found prone to such a risky condition were the ones inhabiting near the coastal areas. Characteristically, aside from being located at the forefront of these events, the coastal communities have impacted the resource by the kind of behavioral patterns they exhibited, such as overdependence and overexploitation to achieve their wellbeing. In this paper, we introduce the development of an approach to an assessment of the coupled human- environment using a multi- agent simulation (MAS) model known as Coastal Vulnerability Dynamic Simulator (COVUDS). The COVUDS comprised a human- environmental platform consisting multi- agents with corresponding spatial- based dynamic and static variables. These variables were used to present multiple hypothetical future situations that contribute to the purpose of supporting a more rational management of the coastal ecosystem and their environmental equities. Initially, we present the theoretical and conceptual components that would lead to the development of the COVUDS. These consisted of the human population engaged in behavioral patterns affecting the conditions of coastal ecosystem services; the system of the biophysical environment and changes in patches brought by global environment and local behavioral variations; the policy factors that were important for choosing area- specific interventions; and the decision- making mechanism that integrates the first three components. To guide a future scenario-based application that will be undertaken in a coastal area in the Philippines, the components of the

  18. Modeling the 2014 Ebola Virus Epidemic – Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone

    OpenAIRE

    Siettos, Constantinos; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2015-01-01

    We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case cou...

  19. Rapid response behavior, at room temperature, of a nanofiber-structured TiO2 sensor to selected simulant chemical-warfare agents.

    Science.gov (United States)

    Ma, Xingfa; Zhu, Tao; Xu, Huizhong; Li, Guang; Zheng, Junbao; Liu, Aiyun; Zhang, Jianqin; Du, Huatai

    2008-02-01

    A chemical prototype sensor was constructed based on nanofiber-structured TiO2 and highly sensitive quartz resonators. The gas-sensing behavior of this new sensor to selected simulant warfare agents was investigated at room temperature. Results showed rapid response and good reversibility of this sensor when used with high-purity nitrogen. This provides a simple approach to preparation of materials needed as chemical sensors for selected organic volatiles or warfare agents. PMID:18094961

  20. Integrated Battlefield Environment Simulation Based on Multi-Agent and HLA%基于Multi-Agent和HLA的综合战场环境仿真

    Institute of Scientific and Technical Information of China (English)

    苏春梅; 奚宏明; 王玮; 茅文浩

    2011-01-01

    针对综合战场环境仿真系统在仿真实现中存在的不足,提出将基于多Agent(multi-agent)的复杂系统建模思想和基于高层体系结构(high level architecture,HLA)的仿真技术结合起来的思路.首先用基于多Agent的思想对综合战场环境仿真系统进行分解建模,然后采用基于HLA的分布式仿真技术来实现仿真系统.结果表明,该技术既能降低仿真系统模型的复杂度,又能使仿真成员具有一定的智能性.%Aiming at the shortcomings from the implementation of the integrated battlefield environment simulation system in the simulation, the ideas of combining the modeling methods of complex systems based on Multi-Agent and technologies of distributed interactive simulation based on HLA. Firstly, the methods based on Multi-Agent is used to design the inner models of the integrated battlefield environment simulation system, and then the technologies of distributed interactive simulation based on HLA is used to implement the simulating system, the result indicates that it reduces the complexity of system modeling and provides the federations with intelligence.

  1. 基于多智能体的备件需求仿真模型%Spare Parts Requirement Simulation Model Based on Multi-Agent

    Institute of Scientific and Technical Information of China (English)

    林楠; 郭晓峰; 吴诗辉

    2011-01-01

    On the basis of thorough analysis on the charateristics of m-maintenance policy in UN redundancy system, the spare parts requirements model based on Multi-Agent simulation is presented. The simulation represents the two objects as two kind of Agents: Shop Replaceable Unit(SRU) Agent for working component and SparePart Agent for spare parts, and the state chart models are constructed for both Agents. The control of states for each agent is event-driven, which can inderectly control the system behavior. The effectiveness of the approach is testified by an example.%分析m维修策略在k/N冗余系统的使用特点,提出基于多智能体的备件需求量仿真模型.将工作部件和备件分别用2种Agent表示,即部件(SRU)Agent和备件(SparePart)Agent,并构建各自的状态机模型.采用事件驱动方式控制各个Agent的状态变化,从而间接控制系统的行为.通过算例验证了该方法的适用性.

  2. Acute environmental toxicity and persistence of DEM, a chemical agent simulant: Diethyl malonate. [Diethyl malonate

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, Shu-mei W.; Van Voris, P.; Wentsel, R.S.

    1990-05-01

    The purpose of the following chemical simulant studies is to assess the potential acute environmental effects and persistence of diethyl malonate (DEM). Deposition velocities for DEM to soil surfaces ranged from 0.04 to 0.2 cm/sec. For foliar surfaces, deposition velocities ranged from 0.0002 cm/sec at low air concentrations to 0.05 cm/sec for high dose levels. The residence times or half-lives of DEM deposited to soils was 2 h for the fast component and 5 to 16 h for the residual material. DEM deposited to foliar surfaces also exhibited biphasic depuration. The half-life of the short residence time component ranged from 1 to 3 h, while the longer time component had half-times of 16 to 242 h. Volatilization and other depuration mechanisms reduce surface contaminant levels in both soils and foliage to less than 1% of initial dose within 96 h. DEM is not phytotoxic at foliar mass loading levels of less than 10 {mu}m/cm{sup 2}. However, severe damage is evident at mass loading levels in excess of 17 {mu}g/cm{sup 2}. Tall fescue and sagebrush were more affected than was short-needle pine, however, mass loading levels were markedly different. Regrowth of tall fescue indicated that the effects of DEM are residual, and growth rates are affected only at higher mass loadings through the second harvest. Results from in vitro testing of DEM indicated concentrations below 500 {mu}g/g dry soil generally did not negatively impact soil microbial activity. Short-term effects of DEM were more profound on soil dehydrogenase activity than on soil phosphatase activity. No enzyme inhibition or enhancement was observed after 28 days in incubation. Results of the earthworm bioassay indicate survival to be 86 and 66% at soil doses of 107 and 204 {mu}g DEM/cm{sup 2}, respectively. At higher dose level, activity or mobility was judged to be affected in over 50% of the individuals. 21 refs., 10 figs., 15 tabs.

  3. Nonlinear Acoustics FDTD method including Frequency Power Law Attenuation for Soft Tissue Modeling

    CERN Document Server

    Jiménez, Noé; Sánchez-Morcillo, Víctor; Camarena, Francisco; Hou, Yi; Konofagou, Elisa E

    2014-01-01

    This paper describes a model for nonlinear acoustic wave propagation through absorbing and weakly dispersive media, and its numerical solution by means of finite differences in time domain method (FDTD). The attenuation is based on multiple relaxation processes, and provides frequency dependent absorption and dispersion without using computational expensive convolutional operators. In this way, by using an optimization algorithm the coefficients for the relaxation processes can be obtained in order to fit a frequency power law that agrees the experimentally measured attenuation data for heterogeneous media over the typical frequency range for ultrasound medical applications. Our results show that two relaxation processes are enough to fit attenuation data for most soft tissues in this frequency range including the fundamental and the first ten harmonics. Furthermore, this model can fit experimental attenuation data that do not follow exactly a frequency power law over the frequency range of interest. The main...

  4. Characteristics of Mesh Wave Impedance in FDTD Non-Uniform Mesh

    Institute of Scientific and Technical Information of China (English)

    REN Wu; LIU Bo; GAO Ben-qing

    2005-01-01

    In order to increase the evaluating precision of mesh reflection wave, the mesh wave impedance(MWI) is extended to the non-uniform mesh in 1-D and 2-D cases for the first time on the basis of the Yee's positional relation for electromagnetic field components. Lots of characteristics are obtained for different mesh sizes and frequencies. Then the reflection coefficient caused by the non-uniform mesh can be calculated according to the theory of equivalent transmission line. By comparing it with that calculated by MWI in the uniform mesh, it is found that the evaluating error can be largely reduced and is in good agreement with that directly computed by FDTD method. And this extension of MWI can be used in the error analysis of complex mesh.

  5. FDTD analysis of close-coupled 418 MHz radiating devices for human biotelemetry

    International Nuclear Information System (INIS)

    This paper describes the finite-difference time-domain (FDTD) analysis of antenna-body interaction effects occurring when chest-mounted 418 MHz radio transmitters are used for medical telemetry applications. Whole-body software models (homogeneous, layered and tissue-segmented) were developed for an adult male subject. Using an electrically small (300 mm2) planar loop antenna, calculated radiation efficiencies ranged between 33.5% and 39.2% for a whole-body model, and between 60.7% and 66.1% for a torso; radiation patterns were found to be largely independent of model composition. The computed radiation efficiency for a 21.5 kg phantom representing a six-year-old female was within 1.1 dB of measured results (actual body mass 28 kg) and well-correlated azimuthal radiation patterns were noted. (author)

  6. Use of the FDTD method for time reversal: application to microwave breast cancer detection

    Science.gov (United States)

    Kosmas, Panagiotis; Rappaport, Carey

    2004-05-01

    The feasibility of microwave breast cancer detection with a time reversal algorithm is examined. This time reversal algorithm, based on the finite difference time domain method (FDTD), time reverses not only the recorded field, but also the medium. It compensates for the wave decay and therefore is suitable for lossy media. We present two-dimensional (2D) breast models and geometries, and assume knowledge of the system's response in the absence of tumor (distorted wave Born approximation). Our results illustrate the system's detection and localization abilities, and its robustness to dispersion and measurement noise. Good performance using a simple time reversal mirror shows that this method is a promising technique for microwave imaging, and encourages us to further examine its applicability to microwave breast cancer detection.

  7. Dispersive finite-difference time-domain (FDTD) analysis of the elliptic cylindrical cloak

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. Y.; Ahn, D. [University of Seoul, Seoul (Korea, Republic of)

    2012-05-15

    A dispersive full-wave finite-difference time-domain (FDTD) model is used to calculate the performance of elliptic cylindrical cloaking devices. The permittivity and the permeability tensors for the cloaking structure are derived by using an effective medium approach in general relativity. The elliptic cylindrical invisibility devices are found to show imperfect cloaking, and the cloaking performance is found to depend on the polarization of the incident waves, the direction of the propagation of those waves, the semi-focal distances and the loss tangents of the meta-material. When the semifocal distance of the elliptic cylinder decreases, the performance of the cloaking becomes very good, with neither noticeable scatterings nor field penetrations. For a larger semi-focal distance, only the TM wave with a specific propagation direction shows good cloaking performance. Realistic cloaking materials with loss still show a cloak that is working, but attenuated back-scattering waves exist.

  8. Investigation of a Novel Compact Microstrip Antenna for Radiotelemetry Capsules Based on FDTD

    Institute of Scientific and Technical Information of China (English)

    HUANG Biao; YAN Guo-zheng; LI Qian-ru

    2007-01-01

    The objective of this paper is to design a microstrip patch antenna for the miniature electro-capsule communicating with external recorder at 915 MHz located in Industry, Science, and Medical (ISM) bands. Microstrip antenna design parameters, resonance characteristics and radiation patterns are evaluated using the finite-difference time-domain (FDTD) method. The effects of location of feed point and human body are analyzed, and the radiation performances of the proposed antenna are estimated in terms of radiation patterns. Finally, specific absorption rate (SAR) computations are also performed, and the peak 1-g and 10-g SAR values are calculated. According to peak SAR values, the maximum delivered, power for the designed antenna was found so that the SAR values of the antennas satisfy ANSI limitations.

  9. A four spiral slots microstrip patch antenna for radiotelemetry capsules based on FDTD

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastrointestinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations.

  10. Optimising GPR modelling: A practical, multi-threaded approach to 3D FDTD numerical modelling

    Science.gov (United States)

    Millington, T. M.; Cassidy, N. J.

    2010-09-01

    The demand for advanced interpretational tools has lead to the development of highly sophisticated, computationally demanding, 3D GPR processing and modelling techniques. Many of these methods solve very large problems with stepwise methods that utilise numerically similar functions within iterative computational loops. Problems of this nature are readily parallelised by splitting the computational domain into smaller, independent chunks for direct use on cluster-style, multi-processor supercomputers. Unfortunately, the implications of running such facilities, as well as time investment needed to develop the parallel codes, means that for most researchers, the use of these advanced methods is too impractical. In this paper, we propose an alternative method of parallelisation which exploits the capabilities of the modern multi-core processors (upon which today's desktop PCs are built) by multi-threading the calculation of a problem's individual sub-solutions. To illustrate the approach, we have applied it to an advanced, 3D, finite-difference time-domain (FDTD) GPR modelling tool in which the calculation of the individual vector field components is multi-threaded. To be of practical use, the FDTD scheme must be able to deliver accurate results with short execution times and we, therefore, show that the performance benefits of our approach can deliver runtimes less than half those of the more conventional, serial programming techniques. We evaluate implementations of the technique using different programming languages (e.g., Matlab, Java, C++), which will facilitate the construction of a flexible modelling tool for use in future GPR research. The implementations are compared on a variety of typical hardware platforms, having between one and eight processing cores available, and also a modern Graphical Processing Unit (GPU)-based computer. Our results show that a multi-threaded xyz modelling approach is easy to implement and delivers excellent results when implemented

  11. Agent, autonomous

    OpenAIRE

    Luciani, Annie

    2007-01-01

    The expression autonomous agents, widely used in virtual reality, computer graphics, artificial intelligence and artificial life, corresponds to the simulation of autonomous creatures, virtual (i.e. totally computed by a program), or embodied in a physical envelope, as done in autonomous robots.

  12. How to assess the robustness of a flexible transport using an Agent Based Model? : Some observations on optimal conditions of simulation.

    OpenAIRE

    Lammoglia, Adrien; Marilleau, Nicolas; Josselin, Didier

    2011-01-01

    This paper presents a method to evaluate the robustness of a cooperating flexible transport system based on agents (taxis and clients) and simulated using NetLogo. Analysing a set of 124 scenarios of simulations on a range of synthetic populations (clients) and on various space networks organizations, we assess the sensitivity of a transportation model we proposed. Our main objective is to detect robustness thresholds in flow configurations and system efficiency. The research leads to two mai...

  13. Computational Investigations of Potential Energy Function Development for Metal--Organic Framework Simulations, Metal Carbenes, and Chemical Warfare Agents

    Science.gov (United States)

    Cioce, Christian R.

    sigma donates, and subsequent back-bonding occurs into a pi* antibonding orbital. This is a different type of interaction not seen in the three existing classes of metal-carbene complexes, namely Fischer, Schrock, and Grubbs. Finally, the virtual engineering of enhanced chemical warfare agent (CWA) detection systems is discussed. As part of a U.S. Department of Defense supported research project, in silico chemical modifications to a previously synthesized zinc-porphyrin, ZnCS1, were made to attempt to achieve preferential binding of the nerve agent sarin versus its simulant, DIMP (diisopropyl methylphosphonate). Upon modification, a combination of steric effects and induced hydrogen bonding allowed for the selective binding of sarin. The success of this work demonstrates the role that high performance computing can play in national security research, without the associated costs and high security required for experimentation.

  14. Assessment of a PML Boundary Condition for Simulating an MRI Radio Frequency Coil

    OpenAIRE

    Alayar Kangarlu; Feng Liu; Peterson, Bradley S.; Tamer S Ibrahim; Yunsuo Duan

    2008-01-01

    Computational methods such as the finite difference time domain (FDTD) play an important role in simulating radiofrequency (RF) coils used in magnetic resonance imaging (MRI). The choice of absorbing boundary conditions affects the final outcome of such studies. We have used FDTD to assess the Berenger's perfectly matched layer (PML) as an absorbing boundary condition for computation of the resonance patterns and electromagnetic fields of RF coils. We first experimentally constructed a high-...

  15. Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moradmand Jalali, Hamed; Bashiri, Hadis, E-mail: hbashiri@kashanu.ac.ir; Rasa, Hossein

    2015-05-01

    In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO{sub 2}, ZnO and ZrO{sub 2}) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. - Highlights: • The mechanism and kinetics of uric acid photo-oxidation by irradiation of sun care agents has been obtained by simulation. • The mechanism has been used for free radical production of TiO{sub 2} (rutile and anatase), ZnO and ZrO{sub 2}. • The ratios of photo-activity of ZnO to anastase, rutile and ZrO have been obtained. • By doubling the initial concentrations of mineral oxide, the rate of reaction was doubled. • The optimum ratio of initial concentration of mineral oxides to uric acid has been obtained.

  16. Study of photo-oxidative reactivity of sunscreening agents based on photo-oxidation of uric acid by kinetic Monte Carlo simulation

    International Nuclear Information System (INIS)

    In the present study, the mechanism of free radical production by light-reflective agents in sunscreens (TiO2, ZnO and ZrO2) was obtained by applying kinetic Monte Carlo simulation. The values of the rate constants for each step of the suggested mechanism have been obtained by simulation. The effect of the initial concentration of mineral oxides and uric acid on the rate of uric acid photo-oxidation by irradiation of some sun care agents has been studied. The kinetic Monte Carlo simulation results agree qualitatively with the existing experimental data for the production of free radicals by sun care agents. - Highlights: • The mechanism and kinetics of uric acid photo-oxidation by irradiation of sun care agents has been obtained by simulation. • The mechanism has been used for free radical production of TiO2 (rutile and anatase), ZnO and ZrO2. • The ratios of photo-activity of ZnO to anastase, rutile and ZrO have been obtained. • By doubling the initial concentrations of mineral oxide, the rate of reaction was doubled. • The optimum ratio of initial concentration of mineral oxides to uric acid has been obtained

  17. Mechanistic insights into the luminescent sensing of organophosphorus chemical warfare agents and simulants using trivalent lanthanide complexes.

    Science.gov (United States)

    Dennison, Genevieve H; Johnston, Martin R

    2015-04-20

    Organophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular-based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular-based approaches using non-covalent interactions have gained momentum. This is due, in part, to the potential development of sensors with second-generation properties, such as reversibility and multifunction capabilities. Supramolecular sensors also offer opportunities for incorporation of metal ions allowing for the exploitation of their unique properties. In particular, trivalent lanthanide ions are being increasingly used in the OP CWA sensing event and their use in supramolecular sensors is discussed in this Minireview. We focus on the fundamental interactions of simple lanthanide systems with OP CWAs and simulants, along with the development of more elaborate and complex systems including those containing nanotubes, polymers and gold nanoparticles. Whilst literature investigations into lanthanide-based OP CWA detection systems are relatively scarce, their unique and versatile properties provide a promising platform for the development of more efficient and complex sensing systems into the future. PMID:25649522

  18. Modeling the 2014 Ebola Virus Epidemic - Agent-Based Simulations, Temporal Analysis and Future Predictions for Liberia and Sierra Leone.

    Science.gov (United States)

    Siettos, Constantinos; Anastassopoulou, Cleo; Russo, Lucia; Grigoras, Christos; Mylonakis, Eleftherios

    2015-01-01

    We developed an agent-based model to investigate the epidemic dynamics of Ebola virus disease (EVD) in Liberia and Sierra Leone from May 27 to December 21, 2014. The dynamics of the agent-based simulator evolve on small-world transmission networks of sizes equal to the population of each country, with adjustable densities to account for the effects of public health intervention policies and individual behavioral responses to the evolving epidemic. Based on time series of the official case counts from the World Health Organization (WHO), we provide estimates for key epidemiological variables by employing the so-called Equation-Free approach. The underlying transmission networks were characterized by rather random structures in the two countries with densities decreasing by ~19% from the early (May 27-early August) to the last period (mid October-December 21). Our estimates for the values of key epidemiological variables, such as the mean time to death, recovery and the case fatality rate, are very close to the ones reported by the WHO Ebola response team during the early period of the epidemic (until September 14) that were calculated based on clinical data. Specifically, regarding the effective reproductive number Re, our analysis suggests that until mid October, Re was above 2.3 in both countries; from mid October to December 21, Re dropped well below unity in Liberia, indicating a saturation of the epidemic, while in Sierra Leone it was around 1.9, indicating an ongoing epidemic. Accordingly, a ten-week projection from December 21 estimated that the epidemic will fade out in Liberia in early March; in contrast, our results flashed a note of caution for Sierra Leone since the cumulative number of cases could reach as high as 18,000, and the number of deaths might exceed 5,000, by early March 2015. However, by processing the reported data of the very last period (December 21, 2014-January 18, 2015), we obtained more optimistic estimates indicative of a remission of

  19. [Susceptibility of clinically-isolated bacteria strains to respiratory quinolones and evaluation of antimicrobial agent efficacy by Monte Carlo simulation].

    Science.gov (United States)

    Kosaka, Tadashi; Yamada, Yukiji; Kimura, Takeshi; Kodama, Mai; Fujitomo, Yumiko; Masaki, Nakanishi; Toshiaki, Komori; Keisuke, Shikata; Fujita, Naohisa

    2016-02-01

    Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC₉₀) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC₉₀ values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC₉₀ (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also

  20. Analysis and prediction of effects of the Manchester Triage System on patient waiting times in an emergency department by means of agent-based simulation

    Directory of Open Access Journals (Sweden)

    Schaaf, Michael

    2014-02-01

    Full Text Available [english] A simulation of complex clinical processes is a challenging task and suitable methods need to be found which can capture the influence of relevant factors and their relationships. The Manchester triage system (MTS is widely used in German emergency departments (ED, however the impact on patient waiting times remain difficult to predict. The purpose of this work is the assessment of MTS particularly with regard to the waiting times of different degrees of severity. The methodology of agent based simulation was found suitable for the ED domain and the agent based simulation tool SeSAm was chosen due to its intuitive user interface and easy adaption of the simulation models. Altogether four agent classes could be implemented based on the information derived from a process model. The model permits a dynamic simulation of the ED processes and a reliable assessment of patient waiting times. In addition, the implementation of a triage nurse allowed the simulation of the triage process and a direct comparison to the current state without a standardized triage procedure. Essential influencing factors (e.g. number of patients, manning level were implemented and their effects on the ED processes and patient waiting times assessed. The simulation runs delivered correct results based on the underlying process model and the collected statistical data. The process flow and the waiting times of an ED could be mapped exactly. In all simulation runs the waiting times of high triage levels (MTS-levels 1 and 2 could be reduced. Especially patients of MTS-level 2 in the waiting area of the ED benefit significantly from the implementation of a standardized triage procedure and the associated permanent monitoring.

  1. Design of a multi-agent hydroeconomic model to simulate a complex human-water system: Early insights from the Jordan Water Project

    Science.gov (United States)

    Yoon, J.; Klassert, C. J. A.; Lachaut, T.; Selby, P. D.; Knox, S.; Gorelick, S.; Rajsekhar, D.; Tilmant, A.; Avisse, N.; Harou, J. J.; Gawel, E.; Klauer, B.; Mustafa, D.; Talozi, S.; Sigel, K.

    2015-12-01

    Our work focuses on development of a multi-agent, hydroeconomic model for purposes of water policy evaluation in Jordan. The model adopts a modular approach, integrating biophysical modules that simulate natural and engineered phenomena with human modules that represent behavior at multiple levels of decision making. The hydrologic modules are developed using spatially-distributed groundwater and surface water models, which are translated into compact simulators for efficient integration into the multi-agent model. For the groundwater model, we adopt a response matrix method approach in which a 3-dimensional MODFLOW model of a complex regional groundwater system is converted into a linear simulator of groundwater response by pre-processing drawdown results from several hundred numerical simulation runs. Surface water models for each major surface water basin in the country are developed in SWAT and similarly translated into simple rainfall-runoff functions for integration with the multi-agent model. The approach balances physically-based, spatially-explicit representation of hydrologic systems with the efficiency required for integration into a complex multi-agent model that is computationally amenable to robust scenario analysis. For the multi-agent model, we explicitly represent human agency at multiple levels of decision making, with agents representing riparian, management, supplier, and water user groups. The agents' decision making models incorporate both rule-based heuristics as well as economic optimization. The model is programmed in Python using Pynsim, a generalizable, open-source object-oriented code framework for modeling network-based water resource systems. The Jordan model is one of the first applications of Pynsim to a real-world water management case study. Preliminary results from a tanker market scenario run through year 2050 are presented in which several salient features of the water system are investigated: competition between urban and

  2. Modelling Temporal Schedule of Urban Trains Using Agent-Based Simulation and NSGA2-BASED Multiobjective Optimization Approaches

    Science.gov (United States)

    Sahelgozin, M.; Alimohammadi, A.

    2015-12-01

    Increasing distances between locations of residence and services leads to a large number of daily commutes in urban areas. Developing subway systems has been taken into consideration of transportation managers as a response to this huge amount of travel demands. In developments of subway infrastructures, representing a temporal schedule for trains is an important task; because an appropriately designed timetable decreases Total passenger travel times, Total Operation Costs and Energy Consumption of trains. Since these variables are not positively correlated, subway scheduling is considered as a multi-criteria optimization problem. Therefore, proposing a proper solution for subway scheduling has been always a controversial issue. On the other hand, research on a phenomenon requires a summarized representation of the real world that is known as Model. In this study, it is attempted to model temporal schedule of urban trains that can be applied in Multi-Criteria Subway Schedule Optimization (MCSSO) problems. At first, a conceptual framework is represented for MCSSO. Then, an agent-based simulation environment is implemented to perform Sensitivity Analysis (SA) that is used to extract the interrelations between the framework components. These interrelations is then taken into account in order to construct the proposed model. In order to evaluate performance of the model in MCSSO problems, Tehran subway line no. 1 is considered as the case study. Results of the study show that the model was able to generate an acceptable distribution of Pareto-optimal solutions which are applicable in the real situations while solving a MCSSO is the goal. Also, the accuracy of the model in representing the operation of subway systems was significant.

  3. MODELLING TEMPORAL SCHEDULE OF URBAN TRAINS USING AGENT-BASED SIMULATION AND NSGA2-BASED MULTIOBJECTIVE OPTIMIZATION APPROACHES

    Directory of Open Access Journals (Sweden)

    M. Sahelgozin

    2015-12-01

    Full Text Available Increasing distances between locations of residence and services leads to a large number of daily commutes in urban areas. Developing subway systems has been taken into consideration of transportation managers as a response to this huge amount of travel demands. In developments of subway infrastructures, representing a temporal schedule for trains is an important task; because an appropriately designed timetable decreases Total passenger travel times, Total Operation Costs and Energy Consumption of trains. Since these variables are not positively correlated, subway scheduling is considered as a multi-criteria optimization problem. Therefore, proposing a proper solution for subway scheduling has been always a controversial issue. On the other hand, research on a phenomenon requires a summarized representation of the real world that is known as Model. In this study, it is attempted to model temporal schedule of urban trains that can be applied in Multi-Criteria Subway Schedule Optimization (MCSSO problems. At first, a conceptual framework is represented for MCSSO. Then, an agent-based simulation environment is implemented to perform Sensitivity Analysis (SA that is used to extract the interrelations between the framework components. These interrelations is then taken into account in order to construct the proposed model. In order to evaluate performance of the model in MCSSO problems, Tehran subway line no. 1 is considered as the case study. Results of the study show that the model was able to generate an acceptable distribution of Pareto-optimal solutions which are applicable in the real situations while solving a MCSSO is the goal. Also, the accuracy of the model in representing the operation of subway systems was significant.

  4. Remote Continuous Wave and Pulsed Laser Raman Detection of Chemical Warfare Agents Simulants and Toxic Industrial Compounds

    Science.gov (United States)

    Ortiz-Rivera, William; Pacheco-Londoño, Leonardo C.; Hernández-Rivera, Samuel P.

    2010-09-01

    This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser detection. Standoff distances for pulsed measurements were 35 m for dimethyl methylphosphonate (DMMP) detection and 60, 90 and 140 m for cyclohexane detection. The prototype systems consisted of a Raman spectrometer equipped with a CCD detector (for CW measurements) and an I-CCD camera with time-gated electronics (for pulsed laser measurements), a reflecting telescope, a fiber optic assembly, a single-line CW laser source (514.5, 488.0, 351.1 and 363.8 nm) and a frequency-doubled single frequency Nd:YAG 532 nm laser (5 ns pulses at 10 Hz). The telescope was coupled to the spectrograph using an optical fiber, and filters were used to reject laser radiation and Rayleigh scattering. Two quartz convex lenses were used to collimate the light from the telescope from which the telescope-focusing eyepiece was removed, and direct it to the fiber optic assembly. To test the standoff sensing system, the Raman Telescope was used in the detection of liquid TIC: benzene, chlorobenzene, toluene, carbon tetrachloride, cyclohexane and carbon disulfide. Other compounds studied were CWAS: dimethylmethyl phosphonate, 2-chloroethyl ethyl sulfide and 2-(butylamino)-ethanethiol. Relative Raman scattering cross sections of liquid CWAS were measured using single-line sources at 532.0, 488.0, 363.8 and 351.1 nm. Samples were placed in glass and quartz vials at the standoff distances from the telescope for the Remote Raman measurements. The mass of DMMP present in water solutions was also quantified as part of the system performance tests.

  5. Modelling and simulation of electrical energy systems through a complex systems approach using agent-based models. Case study: Under-frequency load shedding for refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Kremers, Enrique [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). European Inst. for Energy Research (EIFER); Gonzalez de Durana, Jose Maria; Barambones, Oscar [Universidad del Pais Vasco, Vitoria (Spain). Escuela Universitaria de Ingenieria de Vitoria-Gasteiz

    2013-09-01

    One of the ways of studying complex systems is through modelling and simulation, which are used as tools to represent these systems in a virtual environment. Current advances in computing performance (which has been a major constraint in this field for some time) allow for the simulation these kinds of systems within reasonable time horizons. One of the tools for simulating complex systems is agent-based modelling. This individual-centric approach is based on autonomous entities that can interact with each other, thus modelling the system in a disaggregated way. Agent-based models can be coupled with other modelling methods, such as continuous models and discrete events, which can be embedded or run in parallel to the multi-agent system. When representing the electrical energy system in a systemic and multi-layered way, it is treated as a true socio-technical system, in which not only technical models are taken into account, but also socio-behavioural ones. In this work, a number of different models for the parts of an electrical system are presented, related to production, demand and storage. The models are intended to be as simple as possible in order to be simulated in an integrated framework representing the system as a whole. Furthermore, the models allow the inclusion of social behaviour and other, not purely engineering-related aspects of the system, which have to be considered from a complex point of view. (orig.)

  6. 移动区域建模在Agent仿真中的应用%Application of Mobile Region Modeling in Agent Simulation

    Institute of Scientific and Technical Information of China (English)

    沈沛; 蒋夏军

    2012-01-01

    With increasing application related to mobile regions, the model based on mobile points can not fit well with these applications. Therefore, a rising simulation technology and extensible Markup Language(XML) are adopted. For the limitation of Agent model based on mobile points, a new Agent model for mobile region is proposed, the states of Agents in simulation are stored to the XML database, and the datum in the database can be used for simulation playback or after action analysis. Simulation experiment proves its feasibility.%目前有关移动区域的应用不断增加,而传统的移动点模型已不能很好地适应移动区域的应用.为此,针对基于移动点Agent模型的局限性,提出一种新的基于移动区域的Agent模型,该模型结合新Agent技术及XML技术,将仿真运行过程中的Agent状态记录到移动对象XML数据库,以便于仿真回放和仿真事后分析.仿真实验结果证明了该模型的可行性.

  7. A study of two kinds of electromagnetic pulse antennas with a continuous resistive loading using the FDTD method

    International Nuclear Information System (INIS)

    The cylindrical and conical monopole antenna with a continuous resistive loading is considered as a radiator in the experiments of the electromagnetic pulse compatibility. The various principle of the resistive loading is discussed in details and the characters of the antennas are studied using the Finite-Difference Time-Domain (FDTD) method. The key techniques of the calculating are presented. The results are in good agreement with the documents and the theory

  8. Photonic-Crystal Band-pass Resonant Filters Design Using the Two-dimensional FDTD Method

    Directory of Open Access Journals (Sweden)

    Hadjira Badaoui

    2011-05-01

    Full Text Available Recently, band-pass photonic crystal filters have attracted great attention due to their important applications in the fields of optical interconnection network and ultrahigh speed information processing. In this paper we propose the design of a new type of photonic crystal band-pass resonant filters realized in one-missing-row waveguide by decreasing proper defects along the waveguide with broadband acceptable bandwidth. Two types of photonic crystal band-pass filters are utilized and optimized using the Two-dimensional finite-difference time-domain (FDTD technique. The first one is based on the Fabry-Perot cavities and in the second one a cavity is introduced in the middle by omitting two neighboring air holes in waveguide. Numerical results show that a band [1.47 and#956;m-1.57 and#956;m] around 1.55um is transmitted with a maximum transmission of about 68% and as a result wide band-pass filters are designed.

  9. Analysis of Ringing and Noise in FE and FDTD Calculated Acoustic Pulse Profiles

    Directory of Open Access Journals (Sweden)

    Arthur Every

    2012-10-01

    Full Text Available Ringing, i.e. the emergence of an oscillatory tail behind a wave pulse as it propagates through a medium, is a pervasive artefact in FE and FDTD calculated waveforms. It is known to be a consequence of numerical dispersion arising from the discretization of the equations of motion. The use of an irregular mesh in a FE code has the further consequence of rendering the displacement field increasingly noisy with distance behind the wave front. In this paper these effects are illustrated using the commercial FE package ABAQUS with square and irregular triangular meshes to calculate the progress of a longitudinally polarized Ricker pulse along the axis of a cylindrically shaped aluminium specimen. We are able to give a precise analytical account of the evolution of ringing on the basis of a low order approximation for the dispersion relation of the discretized equations of motion. A qualitative account is provided of the generation of noise in the use of an irregular triangular mesh.

  10. A corner-free truncation strategy for FDTD method in target scattering

    Science.gov (United States)

    Zhang, Yuxian; Feng, Naixing; Zheng, Henry Hongxing; Liu, Qing Huo

    2015-12-01

    In this paper, the corner-free truncation (CFT) strategy is proposed to terminate the circular boundary out of finite-difference time-domain (FDTD) region. Using the principle of reflection-free optimal thin film, the permittivity ε and the permeability μ have been extended to the complex field. The electric conductivity σe and the equivalent magnetic loss σm relate to the complex value and are suitable for the impedance-matched condition (IMC). The propagation wave can be absorbed well at the circular boundary. Moreover, computational efficiency has been much enhanced when those useless square-corners have been eliminated by using the proposed method. In TMz wave, the sinusoidal wave is set near the circular boundary. Applying the CFT strategy, the Ez amplitudes and phases show the concentric circles in the different timesteps. Compared with the square PML, numerical experiments in near- and far-field have come to the fulfillment. At the same numerical example, the CFT strategy has higher accuracy than the conformal PML. These results have fully verified the effectiveness of the proposed algorithm.

  11. Research of HLA Air-Defense Simulation System Based on Agent%基于Agent的HLA空防对抗仿真系统研究

    Institute of Scientific and Technical Information of China (English)

    李云芳; 万晓冬

    2012-01-01

    以防空作战为背景,介绍了防空作战仿真系统的组成结构,对防空作战中各成员的功能进行了分析,建立了系统中火力单元指控的Agent模型结构.通过分析各Agent之间的联系,建立了多Agent之间的交互关系,并详细描述了火力单元指控的射击指挥行为过程.最后,给出了基于Agent模型的火力单元指挥控制仿真实例,验证模型的可行性.%The structure of air-defense combat simulation system was introduced, and the member function of air-defense combat was analyzed for air defense operations. Then, Agent model structure of firepower unit command and control was built Through the analysis of the relationship between the various Agent, the interaction between the Agent was established. Also, detailed descriptions of firing command action plan was given. Finally, The simulation example of firepower unit command and control is given based on Agent model, verified the feasibility of the model.

  12. Agent-based simulation of emergency response to plan the allocation of resources for a hypothetical two-site major incident.

    OpenAIRE

    Hawe, G.I.; Coates, G.; Wilson, D. T.; Crouch, R. S.

    2015-01-01

    During a major incident, the emergency services work together to ensure that those casualties who are critically injured are identified and transported to an appropriate hospital as fast as possible. If the incident is multi-site and resources are limited, the efficiency of this process is compromised as the finite resources must be shared among the multiple sites. In this paper, agent-based simulation is used to determine the allocation of resources for a two-site incident which minimizes th...

  13. Assessing the Carrying Capacity of Tourist Resorts: An Application of Tourists' Spatial Behavior Simulator Based on GIS and Multi-Agent System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ren-jun

    2005-01-01

    Based on the study of visitors' individual spatial behaviors, a tourists' spatial behavior simulator (TSBS) to assess the carrying capacity of tourist resorts was developed, TSBS employs GIS (Geographic Information System) to manage the spatial data, and Multi-Agent system to simulate the actions of individual visitors. By utilizing TSBS, visitors' travel patterns such as location, cost, and state can be analyzed and predicted. Based on this analysis and prediction, the model of assessing the carrying capacity of resorts is built. Our results show that TSBS will be an effective tool to accurately assess the carrying capacity of tourist resorts.

  14. On-lattice agent-based simulation of populations of cells within the open-source Chaste framework

    OpenAIRE

    Figueredo, G.; Joshi, T.; Osborne, J.; Byrne, H. M.; Owen, M

    2013-01-01

    Over the years, agent-based models have been developed that combine cell division and reinforced random walks of cells on a regular lattice, reaction–diffusion equations for nutrients and growth factors; and ordinary differential equations for the subcellular networks regulating the cell cycle. When linked to a vascular layer, this multiple scale model framework has been applied to tumour growth and therapy. Here, we report on the creation of an agent-based multi-scale environment amalgamatin...

  15. Addendum to: “A FDTD analysis on magnetized plasma of Epstein distribution and reflection calculation” [Computer Physics Communications 180 (1) (2009) 55-60]. A short comment on the equivalence of the shift-operator FDTD method and the bilinear frequency approximation technique for modeling dispersive electromagnetic applications

    Science.gov (United States)

    Ramadan, Omar

    2010-07-01

    Recently, the shift operator finite difference time domain (SO-FDTD) method has been introduced by Yang [Computer Physics Communications 180 (1) (2009) 55-60] for modeling dispersive electromagnetic applications. This letter discuss the equivalence of this scheme and the well-known bilinear frequency approximation technique used in the field of digital signal processing. Although the SO-FDTD scheme looks different at first glance, it has been observed that it is fully equivalent to the bilinear frequency approximation technique. Consequently, the SO-FDTD scheme is indeed a bilinear transform operation which is unfortunately not cited by the author.

  16. Thread Group Multithreading: Accelerating the Computation of an Agent-Based Power System Modeling and Simulation Tool -- C GridLAB-D

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Shuangshuang; Chassin, David P.

    2014-01-06

    GridLAB-DTM is an open source next generation agent-based smart-grid simulator that provides unprecedented capability to model the performance of smart grid technologies. Over the past few years, GridLAB-D has been used to conduct important analyses of smart grid concepts, but it is still quite limited by its computational performance. In order to break through the performance bottleneck to meet the need for large scale power grid simulations, we develop a thread group mechanism to implement highly granular multithreaded computation in GridLAB-D. We achieve close to linear speedups on multithreading version compared against the single-thread version of the same code running on general purpose multi-core commodity for a benchmark simple house model. The performance of the multithreading code shows favorable scalability properties and resource utilization, and much shorter execution time for large-scale power grid simulations.

  17. Solution of two-dimensional electromagnetic scattering problem by FDTD with optimal step size, based on a semi-norm analysis

    International Nuclear Information System (INIS)

    To solve the electromagnetic scattering problem in two dimensions, the Finite Difference Time Domain (FDTD) method is used. The order of convergence of the FDTD algorithm, solving the two-dimensional Maxwell’s curl equations, is estimated in two different computer implementations: with and without an obstacle in the numerical domain of the FDTD scheme. This constitutes an electromagnetic scattering problem where a lumped sinusoidal current source, as a source of electromagnetic radiation, is included inside the boundary. Confined within the boundary, a specific kind of Absorbing Boundary Condition (ABC) is chosen and the outside of the boundary is in form of a Perfect Electric Conducting (PEC) surface. Inserted in the computer implementation, a semi-norm has been applied to compare different step sizes in the FDTD scheme. First, the domain of the problem is chosen to be the free-space without any obstacles. In the second part of the computer implementations, a PEC surface is included as the obstacle. The numerical instability of the algorithms can be rather easily avoided with respect to the Courant stability condition, which is frequently used in applying the general FDTD algorithm

  18. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    Science.gov (United States)

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO. PMID:26653465

  19. Comparação entre o MoM e o FDTD na análise de antenas

    OpenAIRE

    Agostinho, Nujoma Sancho Quaresma

    2008-01-01

    Este trabalho de dissertação teve como ponto central o estudo comparativo entre o Método MoM (Method of Moment) e o Método FDTD (Finite DifferenceTime Domain), analisando o desempenho de cada um deles com base em simulações de exemplos de antenas, específicas. Para cada exemplo comparouse os resultados obtidos, pelos dois simuladores, relativos a alguns parâmetros importantes tais como a impedância de entrada, o VSWR e os diagramas de radiação. Para antenas do tipo fil...

  20. The effect of nitrate, bicarbonate and natural organic matter on the degradation of sunscreen agent p-aminobenzoic acid by simulated solar irradiation

    International Nuclear Information System (INIS)

    Our experiments revealed that a model sunscreen agent, p-aminobenzoic acid (PABA), can be effectively transformed through reactions that are mediated by simulated solar irradiation. We systematically explored the effects of nitrate ions, bicarbonate and different types of natural organic matter (NOM) on the degradation of PABA by simulated solar irradiation. Experimental data suggest that these components ubiquitous in nature water have different influence on the rates of the photoinduced removal of PABA. Products were extracted and analyzed using LC/MS and a total of four products probably resulting from ·OH and ·NO2 radicals attack were identified and the possible reaction pathways were proposed. The findings in this study provide useful information for understanding the environmental transformation of sunscreen agent in aquatic system. - Highlights: → In this study, we found that p-aminobenzoic acid (PABA) can be removed by simulated solar irradiation from water. → Influence of environmental components on the photodegradation of PABA was further studied. → We verified using LC/MS that PABA was transformed into four compounds. → We proposed the possible reaction pathways probably resulting from ·OH and ·NO2 radicals attack to PABA.

  1. New methodology for analysis of performance for diverting agents in unconsolidated sandstones in real time with physical simulator using computed tomography

    International Nuclear Information System (INIS)

    While oil and gas wells have the advantage of being able to expel naturally damaging particles produced during the drilling and/or completion phase, water injector wells are prone to accumulating particles up to their completion. In order to remove these particles and restore the potential injectivity of these wells, acid treatments are usually required. One of the major challenges of these operations is to accomplish treatment diversion. If the interval consists of layers with different permeabilities, the acid will preferably penetrate high-permeability layers, leaving the zones of minor permeability without treatment. Even if the reservoir is not a homogeneous one, the damage may not be uniformly distributed and the lack of a good method to obtain a better acid distribution may not be able to remove a significant part of the damage, since acid will penetrate only areas with minor damage. To enable diversion, a highly effective material quantity and concentration is required. The diverting agent must also be non-damaging, low-cost and easy-to-use. The diverting agent studied has shown a good performance for permeabilities up to 3 Darcy. The main advantage of the diverting agent, besides its high-divergence capacity, is the specific action that forms channels into the pores of the reservoir where only oil can flow due to the high-hygroscopic characteristic that capture the water around the pores. And finally the diverting agent after treatment has the capability to remove itself along with the oil produced in treated wells. This eliminates the need for subsequent treatments that would increase time and cost. In this study, X-ray Computed Tomography (CT) scanning was used to evaluate the performance of diverting agents in real time in rock-fluid interactions. A special aluminum cell (physical simulator) was designed to simulate as accurately as possible the same conditions found in a real oil well. For example, pressure, temperature, fluid pressure injection

  2. Simulation for Urban Population Distribution Based on GIS and Multi-agent%基于GIS和多智能体的城市人口分布模拟

    Institute of Scientific and Technical Information of China (English)

    康停军; 张新长; 赵元; 王海鹰; 张维

    2012-01-01

    The importance of spatial distribution of urban population data is analyzed. Aiming at the disadvantages of the usual methods of urban population distribution, a simulation model for urban population distribution is developed with integration of multi-agent and population migration theory (Simulation Model for Urban Population Distribution-SMUPD), which consists of external environment, multi-agent and rules. Residential land has been divided into regular residential cells, based on the initial condition; each residential cell has the same amount of agent. Agents decide whether to migrate or not, and select the appropriate residential cell to make migration. The population distribution is formed by means of the constant decision-making, consult and migration of agents. Experiments indicate that, the simulation result of SMUPD not only has higher accuracy, but also is close to the actual residential segregation pattern. In conclusion, the SMUPD provides a new way of modeling urban population distribution.%传统的城市人口空间分布方法仅能在数量上达到较高的模拟精度,但是不能对城市人口分布表现的居住分异特性进行描述.针对常用的城市人口空间分布模拟方法的不足,构建了基于多智能体的城市人口分布模拟模型,模型由影响要素、智能体、决策规则等组成.居住用地划分为均匀的居住元胞,初始状态下,每个居住元胞分布相同数量的智能体(家庭为单位),智能体在各自居住压力作用下做出是否迁居的决策,如果迁居则选择合适的居住元胞,通过智能体的不断决策、协商、迁居模拟城市人口分布的变化.实验结果表明,相对于传统的重力模型,本文模型所模拟的结果不仅具有较高的精度,而且模拟的城市居住分异现象与现实居住格局相符合,为城市人口分布模拟提供了新的思路.

  3. Study on an agent based simulation of banking queuing system%基于Agent的银行业务排队系统仿真研究

    Institute of Scientific and Technical Information of China (English)

    张琦琮; 杨公平

    2011-01-01

    为解决目前办理银行业务顾客等候时间过长的问题,构建了基于Agent的排队系统仿真模型。通过将顾客、排队机、服务台和自动柜员机等抽象为不同的Agent以及不同Agent之间的交互仿真了银行业务排队系统的运行。模型中给出了一种服务队列动态调整的算法,在netlogo平台上进行了模型建立和算法实现。实验数据和分析显示,此模型真实地模拟了银行排队系统运行,合理利用了现有资源,减少了顾客平均等待时间,提升了顾客满意度。%In order to reduce the waiting time of customers in the current banking system,an agent-based simulation model of banking queuing system was developed.The customer,queue machine,server and automatic teller machine were abstracted as different agents.The situation of the system was simulated through the interaction among agents.A proposed algorithm for adjusting queues dynamically was implemented in the netlogo platform.Experimental data and analysis showed that the model could simulate the real operation of the banking queuing system,rationally use existing resources,reduce the average waiting time of customer and enhance customer satisfaction.

  4. Efficiency and Effectiveness of C2C Interactions and Mutual Learning for Value Co-Creation: Agent-Based Simulation Approach

    Directory of Open Access Journals (Sweden)

    Santi Novani

    2013-04-01

    Full Text Available The active role of customers and their experience to create the value in service system have been recognized inthe literature. So far, the focus of value co-creation only for business-business (B2B or business-customers(B2C, meanwhile the attention to the customer-to-customer (C2C is not so much. Recently, the attention toC2C interaction is increasingly viewed by marketer and researcher. However, the existing research of C2C is onthe conceptual and empirical model, therefore it may not describe C2C interaction dynamically. In this research,we show and develop a model of customers’ interaction by using agent-based simulation to capture the dynamicof interaction. The research aim is to explore how effective and efficient C2C by engaging customers’experience in value co-creation. Furthermore, we investigate the needs of mutual learning by using agent basedsimulation. The previous research is focus on two types of C2C interaction, i.e., face-to-face and social mediainteraction. In the present research, we show more general the needs of human interaction by engagingcustomers’ experience which compare between ‘customer-to-customer (C2C interaction’ and ‘no interaction’(i.e., customers interact with the provider directly without interaction with other customers. By conductingagent based simulation, we investigate how C2C interaction is effective which measured by learningperformance and how efficient which measured by learning efficiency. On the other hand, we conductsensitivity analysis to investigate the needs of mutual learning between customers and provider in valueco-creation. In our simulation result, it shows customer-to-customer (C2C interaction gives significantinfluence than ’no interaction’. Moreover, we have already shown the needs mutual learning between customersand provider from the simulation results.

  5. The promise and perils of pre-publication review: a multi-agent simulation of biomedical discovery under varying levels of review stringency.

    Directory of Open Access Journals (Sweden)

    Jeff Shrager

    Full Text Available The Internet has enabled profound changes in the way science is performed, especially in scientific communications. Among the most important of these changes is the possibility of new models for pre-publication review, ranging from the current, relatively strict peer-review model, to entirely unreviewed, instant self-publication. Different models may affect scientific progress by altering both the quality and quantity of papers available to the research community. To test how models affect the community, I used a multi-agent simulation of treatment selection and outcome in a patient population to examine how various levels of pre-publication review might affect the rate of scientific progress. I identified a "sweet spot" between the points of very limited and very strict requirements for pre-publication review. The model also produced a u-shaped curve where very limited review requirement was slightly superior to a moderate level of requirement, but not as large as the aforementioned sweet spot. This unexpected phenomenon appears to result from the community taking longer to discover the correct treatment with more strict pre-publication review. In the parameter regimens I explored, both completely unreviewed and very strictly reviewed scientific communication seems likely to hinder scientific progress. Much more investigation is warranted. Multi-agent simulations can help to shed light on complex questions of scientific communication and exhibit interesting, unexpected behaviors.

  6. The Power Trading Agent Competition

    OpenAIRE

    Ketter, W.; Collins, J.; REDDY, P; Flath, C.

    2011-01-01

    This is the specification for the Power Trading Agent Competition for 2011 (Power TAC 2011). Agents are simulations of electrical power brokers, who must compete with each other for both power production and consumption, and manage their portfolios.

  7. Numerical Simulation of Evacuation Process in Malaysia By Using Distinct-Element-Method Based Multi-Agent Model

    Science.gov (United States)

    Abustan, M. S.; Rahman, N. A.; Gotoh, H.; Harada, E.; Talib, S. H. A.

    2016-07-01

    In Malaysia, not many researches on crowd evacuation simulation had been reported. Hence, the development of numerical crowd evacuation process by taking into account people behavioral patterns and psychological characteristics is crucial in Malaysia. On the other hand, tsunami disaster began to gain attention of Malaysian citizens after the 2004 Indian Ocean Tsunami that need quick evacuation process. In relation to the above circumstances, we have conducted simulations of tsunami evacuation process at the Miami Beach of Penang Island by using Distinct Element Method (DEM)-based crowd behavior simulator. The main objectives are to investigate and reproduce current conditions of evacuation process at the said locations under different hypothetical scenarios for the efficiency study of the evacuation. The sim-1 is initial condition of evacuation planning while sim-2 as improvement of evacuation planning by adding new evacuation area. From the simulation result, sim-2 have a shorter time of evacuation process compared to the sim-1. The evacuation time recuded 53 second. The effect of the additional evacuation place is confirmed from decreasing of the evacuation completion time. Simultaneously, the numerical simulation may be promoted as an effective tool in studying crowd evacuation process.

  8. Numerical simulation to study the feasibility of using CO2 as a stimulation agent for enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Xu, T.; Zhang, W.; Pruess, K.

    2009-11-15

    A major concern in the development of enhanced geothermal systems (EGS) is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths such as those caused by thermally-induced stress cracking. Past researches have tended to focus primarily on thermal and hydraulic stimulation. Recent studies suggest that chemical stimulation may improve the performance of EGS reservoirs. Geothermal injection wells are often drilled into formations containing reactive minerals such as calcite. Injecting aqueous chemical agents such as mineral acids, could be effective for mineral dissolution and porosity enhancement at distances of several meters around a well. An alternative to treatment with strong acids is the use of supercritical (SC) CO{sub 2} as stimulation agent for an aqueous-based EGS. Reactive transport modeling is used to investigate the effectiveness of this method. We used the thermal condition and mineralogical composition from a well of Desert Peak EGS site, to examine ways in which mixtures of water and CO{sub 2} can be injected to enhance porosity.

  9. Dynamic simulation of impact factors on mono-centric urbanization by using agent-based modeling%基于自主体(agent)的单中心城市化动态模拟

    Institute of Scientific and Technical Information of China (English)

    薛领; 翁谨; 杨开忠; 李国平

    2009-01-01

    构建了基于自主体(agent)的单中心城市化模拟模型,实现了一个人工可控的计算实验环境.围绕人口流动、扩大内需、集聚效应等城市化进程的影响因素以及城市化与工业化关系展开模拟分析和讨论.研究表明:(1)城乡消费倾向扩大有助于城市与农村地区收入的提高,也有助于提高城市化水平;(2)随着集聚过程的负效应增大,城市化水平相应下降,甚至不可持续;(3)城市化与工业化具有较强的相关性,经济结构比值随着城市化水平上升而不断提高,而且工业化进程要快于城市化过程.本文认为,基于自主体建模为研究和揭示我国城市化过程的动态规律和驱动机制提供了一条新的途径.我国城市化研究需要结合转型时期的基本国情,探索演绎分析、计算实验以及实证研究相结合的技术路线.%In this paper, the UrbanSwarm, a computational environment, is developed for a better understanding of urbanization by agent-based modeling. UrbanSwarm contains mul-tiple economic interactions between urban and rural agents that are crucial in urbanization process and mechanism because the basic force driving the urbanization is inherently micro-scopic. This paper gives a detailed discussion on the influencing factors such as migration policy, domestic demand, and negative effect of agglomeration on urbanization process in mono-centric scenario. (1) The segmentation policy not only limited the urban-rural mi-gration but enlarged urban-rural income disparity as well. It simulates the household regis-tration system (hukou) before 1978, which confined most Chinese citizens to their places of birth. (2) Raising urban-rural propensity to consumer contributes to both urban-rural income level and urbanization level. Meanwhile, it can narrow the urban-rural gap. (3) With the increase of the negative effect of agglomeration on urbanization, urbanization lev-el drops gradually. The urbanization process

  10. Synthetic benchmark model for parallel agent-based simulation%面向并行Agent仿真的合成基准测试模型

    Institute of Scientific and Technical Information of China (English)

    余文广; 王维平; 侯洪涛; 李群

    2012-01-01

    In order to evaluate the performance of parallel simulation algorithms, there is a need for a benchmark model. To solve the problem that there is currently lack of such a common benchmark model that is independent of applications in the parallel agent-based simulation (PABS) research community, based on the design principles of parallel HOLD which is a classic synthetic benchmark model for parallel discrete event simulations (PDES) , a common benchmark model for PABS is proposed according to the characteristics of agent-based simulations (ABS). This model can easily synthesize various required workloads based on application characteristics and exclude the impact of elements related to specific applications on the performance analysis so as to provide a common benchmark for different PABS researchers. Finally, with this model, the impact of the computation granularity of agents and the number of processors on the speedup is analyzed experimentally.%为了评估并行仿真算法的性能,需要建立一个基准测试模型.针对并行Agent仿真研究领域中缺乏一种与应用无关的基准测试模型这一问题,在借鉴并行离散事件仿真中经典的合成测试模型PHOLD设计思想的基础上,根据基于Agent仿真的特点,提出面向并行Agent仿真的合成基准测试模型,利用该模型可以方便地合成符合不同应用特点的计算负载,去除与应用相关的因素对性能分析的影响,能够为不同的并行Agent仿真研究者提供一个公共的测试基准.最后,采用该模型从实验层次上分析了Agent计算粒度、所采用的处理器数目等因素对并行Agent仿真加速比的影响.

  11. Artificial Force Fields for Multi-agent Simulations of Maritime Traffic: A Case Study of Chinese Waterway

    NARCIS (Netherlands)

    Xiao, F.; Ligteringen, H.; Van Gulijk, C.; Ale, B.J.M.

    2012-01-01

    Collisions are an important factor in probabilistic risk modeling of waterway infrastructures. Especially in the design of bridges and terminals, the probability of ship collision is important. Researchers are looking for simulations that mimic ship behavior and estimate accident probabilities rathe

  12. 基于多智体多库协同的一种虚拟现实仿真界面构建技术%Multi-Agent and Multi-Base-Cooperation based Virtual Reality Simulation Interface Generating Technology

    Institute of Scientific and Technical Information of China (English)

    彭力; 李稳; 娄国焕

    2002-01-01

    An automatic generating method about a kind of virtual reality simulation interface is deeply investigated in his paper. The problem on distributed database cooperation with multi agent system is discussed. A virtral reality system based on these intelligent bases is set up at last. Then a simulation interface by using this system above is got and good result is achieved.

  13. Multi-agent agro-economic simulation of irrigation water demand with climate services for climate change adaptation

    Directory of Open Access Journals (Sweden)

    Stefano Balbi

    2013-09-01

    Full Text Available Farmers’ irrigation practices play a crucial role in the sustainability of crop production and water consumption, and in the way they deal with the current and future effects of climate change. In this study, a system dynamic multi-agent model adopting the soil water balance provided by the Food and Agriculture Organization (FAO Irrigation and Drainage Paper 56 was developed to explore how farmers’ decision making may affect future water needs and use with a focus on the role of climate services, i.e. forecasts and insurance. A climatic projection record representing the down-scaled A1B market scenario (a balance across all sources of the assessment report of the Intergovernmental Panel on Climate Change (IPCC is used to produce future daily data about relative humidity, precipitation, temperature and wind speed. Two types of meteorological services are made available: i a bi-weekly bulletin; and ii seasonal forecasts. The precision of these services was altered to represent different conditions, from perfect knowledge to poor forecasts. Using the available forecasts, farming agents take adaptation decisions concerning crop allocation and irrigation management on the basis of their own risk attitudes. Farmers’ attitudes are characterized by fuzzy classifications depending on age, relative income and crop profitability. Farming agents’ adaptation decisions directly affect the crop and irrigation parameters, which in turn affect future water needs on a territorial level. By incorporating available and future meteorological services, the model allows the farmer’s decision making-process to be explored together with the consequent future irrigation water demand for the period 2015 to 2030. The model prototype is applied to a data set of the Venice Lagoon Watershed, an area of 2038 km2 in north-east Italy, for a preliminary test of its performance and to design future development objectives.

  14. QoS Multicast Routing Algorithm Based on Agent and Simulation%基于Agent的QoS组播路由算法及仿真

    Institute of Scientific and Technical Information of China (English)

    侯丽敏; 张瑞坤

    2011-01-01

    This paper presents an Agent-based QoS multicast routing algorithm. The method used a set of collaborative work Agent network, found the path to meet the QoS request, and selected resource reservation path. Its advantage is that the election Routing Agent is of a certain degree of flexibility and adaptability, the routers themselves do not need to hnve QoS routing functions, and QoS does not need to maintain separate routing tables but only need to provide Agent operating environment and associated data structure. Finally, we carried out an experimental simulation. The simulation results show that the algorithm has good performance, the algorithm and resource reservation calculation does not need a dedicated resource reservation protocol, and exchange nodes do not have to safeguard the overall state of information and the existing modules do not need to been changed a lot to simultaneously support the best data and real-time data delivery.%针对网络质量控制问题,提出一种基于Agent的QoS组播路由算法.方法采用一组协同工作的Agent搜索网络,寻找满足QoS请求的路径,并对选定路径进行资源预留.优点在于Agent选路由具有一定的灵活性与适应性,路由器本身不需要具有QoS路由功能,不需要维持专门的QoS路由表,只需要提供Agent的运行环境和相关数据结构并进行仿真.仿真实验结果表明算法不仅具有较好的性能,并且不需要专门的资源预留协议,不必对现有模块进行大的改动就可以同时支持数据实时投递.

  15. Agents unleashed a public domain look at agent technology

    CERN Document Server

    Wayner, Peter

    1995-01-01

    Agents Unleashed: A Public Domain Look at Agent Technology covers details of building a secure agent realm. The book discusses the technology for creating seamlessly integrated networks that allow programs to move from machine to machine without leaving a trail of havoc; as well as the technical details of how an agent will move through the network, prove its identity, and execute its code without endangering the host. The text also describes the organization of the host's work processing an agent; error messages, bad agent expulsion, and errors in XLISP-agents; and the simulators of errors, f

  16. Three dimensional numerical modeling for ground penetrating radar using finite difference time domain (FDTD) method; Jikan ryoiki yugen sabunho ni yoru chika radar no sanjigen suchi modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sanada, Y.; Ashida, Y.; Sassa, K. [Kyoto University, Kyoto (Japan)

    1996-10-01

    3-D numerical modeling by FDTD method was studied for ground penetrating radar. Radar radiates electromagnetic wave, and determines the existence and distance of objects by reflection wave. Ground penetrating radar uses the above functions for underground surveys, however, its resolution and velocity analysis accuracy are problems. In particular, propagation characteristics of electromagnetic wave in media such as heterogeneous and anisotropic soil and rock are essential. The behavior of electromagnetic wave in the ground could be precisely reproduced by 3-D numerical modeling using FDTD method. FDTD method makes precise analysis in time domain and electric and magnetic fields possible by sequentially calculating the difference equation of Maxwell`s equation. Because of the high calculation efficiency of FDTD method, more precise complicated analysis can be expected by using the latest advanced computers. The numerical model and calculation example are illustrated for surface type electromagnetic pulse ground penetrating radar assuming the survey of steel pipes of 1m deep. 4 refs., 3 figs., 1 tab.

  17. Agent Modeling Based Heavy Infectious Diseases Simulation System Analysis%基于AGENT建模的重大疾病传染仿真系统分析

    Institute of Scientific and Technical Information of China (English)

    朱一凡; 梅珊; 郑涛; 祖正虎

    2011-01-01

    Agent的建模仿真是重大疾病传染建模仿真的发展方向。在深入分析美国相关计算机仿真系统的基础上,基于agent理论和技术,分析设计了重大疾病传染与控制仿真系统的总体框架、体系结构和逻辑结构。对系统关键模型如大气流动模型、疾病病毒散布模型、个体Agent传染模型、Agent感染效应模型和城市地理信息模型等进行了探讨。然后,构建了一个重大疾病传染仿真原型系统。研究可指导重大疾病传染仿真系统的构建,以及该过程涉及的各种模型和技术细节。%Infectious diseases and bioterroristic attacks are of great concerns for national security. Analyses of emergencies and decision making of public health policies are important to holding back epidemics. With analyzing relevant simulation systems developed in the USA, it could be concluded that the agent-based method stands for the future direction of infectious diseases modelling and simulation. Based on agent theory and technology, an overall framework, architecture and logic structure of simulation system for infectious diseases analysis were designed. Then important models such as an air flowing model, a virus spreading model, an individual model, an infection effect model and a city geographical information model, etc., were discussed. Finally, a prototype of heavy infectious diseases simulation system was constructed. The research achievement could guide the construction of simulation system prototypes for severe infectious diseases, and the consideration of various models and techniques.

  18. New simulation approach using classical formalism to water nuclear magnetic relaxation dispersions in presence of superparamagnetic particles used as MRI contrast agents

    Science.gov (United States)

    Vuong, Q. L.; Gossuin, Y.; Gillis, P.; Delangre, S.

    2012-09-01

    Superparamagnetic nanoparticles are used as negative contrast agents in magnetic resonance imaging: owing to their large magnetic moment the water proton spins are dephased, which accelerates the nuclear magnetic relaxation of an aqueous sample containing these particles. Transverse and longitudinal relaxation times depend on several parameters of the nanoparticles such as radius and magnetization and on experimental parameters such as the static magnetic field or echo time. In this work, we introduce a new simulation methodology, using a classical formalism, allowing the simulation of the NMR signal during transverse and longitudinal relaxation induced by superparamagnetic particles in an aqueous solution, which, to our knowledge has never been done before. Nuclear magnetic relaxation dispersion profiles are obtained for a wide range of nanoparticle radii and magnetizations. The results can be classified in two regimes—the well-known motional averaging and static regimes. This generalizes previous studies focusing on transverse relaxation at high magnetic field (larger than 1 T). Simulation results correspond to analytical theories in their validity range and so far unknown dependences of the relaxation with magnetization and radii of the NMR dispersions profiles are observed, which could be used to characterize experimental samples containing large superparamagnetic particles.

  19. Curcumin-I Knoevenagel's condensates and their Schiff's bases as anticancer agents: synthesis, pharmacological and simulation studies.

    Science.gov (United States)

    Ali, Imran; Haque, Ashanul; Saleem, Kishwar; Hsieh, Ming Fa

    2013-07-01

    Pyrazolealdehydes (4a-d), Knoevenagel's condensates (5a-d) and Schiff's bases (6a-d) of curcumin-I were synthesized, purified and characterized. Hemolysis assays, cell line activities, DNA bindings and docking studies were carried out. These compounds were lesser hemolytic than standard drug doxorubicin. Minimum cell viability (MCF-7; wild) observed was 59% (1.0 μg/mL) whereas the DNA binding constants ranged from 1.4×10(3) to 8.1×10(5) M(-1). The docking energies varied from -7.30 to -13.4 kcal/mol. It has been observed that DNA-compound adducts were stabilized by three governing forces (Van der Wall's, H-bonding and electrostatic attractions). It has also been observed that compounds 4a-d preferred to enter minor groove while 5a-d and 6a-d interacted with major grooves of DNA. The anticancer activities of the reported compounds might be due to their interactions with DNA. These results indicated the bright future of the reported compounds as anticancer agents. PMID:23643901

  20. Preliminary evaluation of military, commercial and novel skin decontamination products against a chemical warfare agent simulant (methyl salicylate).

    Science.gov (United States)

    Matar, Hazem; Guerreiro, Antonio; Piletsky, Sergey A; Price, Shirley C; Chilcott, Robert P

    2016-06-01

    Rapid decontamination is vital to alleviate adverse health effects following dermal exposure to hazardous materials. There is an abundance of materials and products which can be utilised to remove hazardous materials from the skin. In this study, a total of 15 products were evaluated, 10 of which were commercial or military products and five were novel (molecular imprinted) polymers. The efficacies of these products were evaluated against a 10 µl droplet of (14)C-methyl salicylate applied to the surface of porcine skin mounted on static diffusion cells. The current UK military decontaminant (Fuller's earth) performed well, retaining 83% of the dose over 24 h and served as a benchmark to compare with the other test products. The five most effective test products were Fuller's earth (the current UK military decontaminant), Fast-Act® and three novel polymers [based on itaconic acid, 2-trifluoromethylacrylic acid and N,N-methylenebis(acrylamide)]. Five products (medical moist-free wipes, 5% FloraFree™ solution, normal baby wipes, baby wipes for sensitive skin and Diphotérine™) enhanced the dermal absorption of (14)C-methyl salicylate. Further work is required to establish the performance of the most effective products identified in this study against chemical warfare agents. PMID:26339920