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Sample records for agents fdtd simulation

  1. 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

    refractive index matching conditions and by cells labeled by gold nanoparticles. The optical schematics including phase contrast (OPCM) microscopy as a prospective modality for in vivo flow cytometry is also analyzed. The validation of the FDTD approach for the simulation of flow cytometry may open a new...

  2. 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

  3. FDTD simulation tools for UWB antenna analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2004-12-01

    This paper describes the development of a set of software tools useful for analyzing ultra-wideband (UWB) antennas and structures. These tools are used to perform finite difference time domain (FDTD) simulation of a conical antenna with continuous wave (CW) and UWB pulsed excitations. The antenna is analyzed using spherical coordinate-based FDTD equations that are derived from first principles. The simulation results for CW excitation are compared to simulation and measured results from published sources; the results for UWB excitation are new.

  4. Nonstandard FDTD Simulation-Based Design of CROW Wavelength Splitters

    Directory of Open Access Journals (Sweden)

    Naoki Okada

    2011-01-01

    Full Text Available The finite-difference time-domain (FDTD algorithm has been used in simulation-based designs of many optical devices, but it fails to reproduce high-Q whispering gallery modes (WGMs. On the other hand, the nonstandard (NS FDTD algorithm can accurately compute WGMs and can be used to make simulation-based designs of WGM devices. Wavelength splitters using the coupled resonator optical waveguides (CROWs based on WGM couplings have recently attracted attention because they are potentially ultracompact. In this paper, we design a CROW wavelength splitter using NS FDTD simulations and demonstrate high interchannel extinction ratios of over 20 dB.

  5. 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).

  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. 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...

  9. 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.

  10. 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)

  11. 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

  12. FDTD Simulation of Exposure of Biological Material to Electromagnetic Nanopulses

    CERN Document Server

    Simicevic, N; Simicevic, Neven; Haynie, Donald T

    2004-01-01

    Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or nanopulses, are of considerable interest to the communications industry and are being explored for various applications in biotechnology and medicine. The propagation of a nanopulse through biological matter has been computed in the time domain using the finite difference-time domain method (FDTD). The approach required existing Cole-Cole model-based descriptions of dielectric properties of biological matter to be re-parametrized using the Debye model, but without loss of accuracy. The approach has been applied to several tissue types. Results show that the electromagnetic field inside a biological tissue depends on incident pulse rise time and width. Rise time dominates pulse behavior inside a tissue as conductivity increases. It has also been found that the amount of energy deposited by 20 $kV/m$ nanopulses is insufficient to change the temperature of the exposed material for the pulse repetition rates of 1 $MHz$ or less.

  13. 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.

  14. 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.

  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. 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.

  18. FDTD Simulation of Transfer Impedance of Calibration Current Target for ESD Testing

    Science.gov (United States)

    Gotoh, Tsuyoshi; Taka, Yoshinori; Mori, Ikuko; Fujiwara, Osamu; Ishigami, Shinobu; Yamanaka, Yukio

    Transient electromagnetic fields caused by electrostatic discharges (ESDs) are known to cause a serious failure in high-tech information devices. From this perspective, an international standard for ESD testing or IEC 61000-4-2 has been specified, in which a detailed waveform of the discharge current to be injected onto equipment under test (EUT) by an ESD-gun is prescribed, and is also required for contact discharges onto a calibration current target called Pellegrini target, which is specially designed so that the waveform of an injected current and its observed voltage coincides. However, the coincidence relationship should not hold at high frequencies due to parasitic components which the target has. In this study, we constructed an FDTD model of the Pellegrini target, and calculated its transfer impedance by simulating the injected current onto the target and the corresponding output voltage in combination with an FDTD model being previously developed for an ESD-gun. As a result, we found that the target has a transfer impedance of almost 1-j0 Ω at less than a few hundred MHz, though it has resonance phenomena around 2-3 GHz, which was validated by measuring scattering parameters of the target through a transmission line with a network analyzer. Using the FDTD-calculated transfer impedance, we reconstructed injected current waveforms for contact and air discharges of an ESD-gun from their observed voltages to reveal that the injected current waveform is almost identical to the observed voltage waveform for the contact discharge, while the injected currents for the air discharges have smaller peaks and longer rise times than the observed voltages do due to the presence of resonance properties of the transfer impedance.

  19. FDTD simulation of finite-amplitude pressure and temperature fields for biomedical ultrasound.

    Science.gov (United States)

    Hallaj, I M; Cleveland, R O

    1999-05-01

    Full wave simulations provide a valuable tool for studying the spatial and temporal nature of an acoustic field. One method for producing such simulations is the finite-difference time-domain (FDTD) method. This method uses discrete differences to approximate derivatives in the governing partial differential equations. We used the FDTD method to model the propagation of finite-amplitude sound in a homogeneous thermoviscous fluid. The calculated acoustic pressure field was then used to compute the transient temperature rise in the fluid; the heating results from absorption of acoustic energy by the fluid. As an example, the transient temperature field was calculated in biological tissue in response to a pulse of focused ultrasound. Enhanced heating of the tissue from finite-amplitude effects was observed. The excess heating was attributed to the nonlinear generation of higher-frequency harmonics which are absorbed more readily than the fundamental. The effect of nonlinear distortion on temperature rise in tissue was observed to range from negligible at 1 MPa source pressure to an 80% increase in temperature elevation at 10 MPa source pressure.

  20. 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.

  1. 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.

  2. Three-Dimensional FDTD Simulation of Biomaterial Exposure to Electromagnetic Nanopulses

    CERN Document Server

    Simicevic, N

    2005-01-01

    Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or nanopulses, have been recently approved by the Federal Communications Commission for a number of various applications. They are also being explored for applications in biotechnology and medicine. The simulation of the propagation of a nanopulse through biological matter, previously performed using a two-dimensional finite difference-time domain method (FDTD), has been extended here into a full three-dimensional computation. To account for the UWB frequency range, a geometrical resolution of the exposed sample was $0.25 mm$, and the dielectric properties of biological matter were accurately described in terms of the Debye model. The results obtained from three-dimensional computation support the previously obtained results: the electromagnetic field inside a biological tissue depends on the incident pulse rise time and width, with increased importance of the rise time as the conductivity increases; no thermal effects are possible for the lo...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. An efficient higher-order PML in WLP-FDTD method for time reversed wave simulation

    Science.gov (United States)

    Wei, Xiao-Kun; Shao, Wei; Ou, Haiyan; Wang, Bing-Zhong

    2016-09-01

    Derived from a stretched coordinate formulation, a higher-order complex frequency shifted (CFS) perfectly matched layer (PML) is proposed for the unconditionally stable finite-difference time-domain (FDTD) method based on weighted Laguerre polynomials (WLPs). The higher-order PML is implemented with an auxiliary differential equation (ADE) approach. In order to further improve absorbing performance, the parameter values of stretching functions in the higher-order PML are optimized by the multi-objective genetic algorithm (MOGA). The optimal solutions can be chosen from the Pareto front for trading-off between two independent objectives. It is shown in a numerical test that the higher-order PML is efficient in terms of attenuating propagating waves and reducing late time reflections. Moreover, the higher-order PML can be placed very close to the wall when analyzing the channel characteristics of time reversal (TR) waves in a multipath indoor environment. Numerical examples of TR wave propagation demonstrate the availability of the proposed method.

  8. 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...

  9. Numerical simulation of metallic nanostructures interacting with electromagnetic fields using the Lorentz-Drude model and FDTD method

    Science.gov (United States)

    Benavides-Cruz, M.; Calderón-Ramón, C.; Gomez-Aguilar, J. F.; Rodríguez-Achach, M.; Cruz-Orduña, I.; Laguna-Camacho, J. R.; Morales-Mendoza, L. J.; Enciso-Aguilar, M.; Pérez-Meana, H.; Escalante-Martínez, J. E.; López-Calderón, J. E.; Juárez-Morales, G.

    2016-10-01

    In this paper, we present an analysis and modeling of the interaction of electromagnetic fields with metallic nanostructures using computational tools that allow us to study the phenomena that are produced as an electromagnetic field interacts with the nanostructure. The analysis of dielectric systems including metals can be very complicated because of the metal parameters. For this reason, we propose to integrate the dielectric function of the Lorentz-Drude model with the finite difference time-domain (FDTD) method, which will permit to study the surface and internal effects within the metal nanostructure system added to the dielectric system, and the interaction of electromagnetic fields with atoms, ions or molecules excited up to their resonant frequency, which causes transitions among atomic energy levels. We solved the system and showed the results of the simulation for the following case studies, silver nanosphere of 100nm in diameter, gold nanorod of 12nm in thickness and 30nm in length and gold nanogroove of 70nm.

  10. An effective approach for road asset management through the FDTD simulation of the GPR signal

    Science.gov (United States)

    Benedetto, Andrea; Pajewski, Lara; Adabi, Saba; Kusayanagi, Wolfgang; Tosti, Fabio

    2015-04-01

    Ground-penetrating radar is a non-destructive tool widely used in many fields of application including pavement engineering surveys. Over the last decade, the need for further breakthroughs capable to assist end-users and practitioners as decision-support systems in more effective road asset management is increasing. In more details and despite the high potential and the consolidated results obtained over years by this non-destructive tool, pavement distress manuals are still based on visual inspections, so that only the effects and not the causes of faults are generally taken into account. In this framework, the use of simulation can represent an effective solution for supporting engineers and decision-makers in understanding the deep responses of both revealed and unrevealed damages. In this study, the potential of using finite-difference time-domain simulation of the ground-penetrating radar signal is analyzed by simulating several types of flexible pavement at different center frequencies of investigation typically used for road surveys. For these purposes, the numerical simulator GprMax2D, implementing the finite-difference time-domain method, was used, proving to be a highly effective tool for detecting road faults. In more details, comparisons with simplified undisturbed modelled pavement sections were carried out showing promising agreements with theoretical expectations, and good chances for detecting the shape of damages are demonstrated. Therefore, electromagnetic modelling has proved to represent a valuable support system in diagnosing the causes of damages, even for early or unrevealed faults. Further perspectives of this research will be focused on the modelling of more complex scenarios capable to represent more accurately the real boundary conditions of road cross-sections. Acknowledgements - This work has benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating

  11. A PML-FDTD ALGORITHM FOR SIMULATING PLASMA-COVERED CAVITY-BACKED SLOT ANTENNAS. (R825225)

    Science.gov (United States)

    A three-dimensional frequency-dependent finite-difference time-domain (FDTD) algorithm with perfectly matched layer (PML) absorbing boundary condition (ABC) and recursive convolution approaches is developed to model plasma-covered open-ended waveguide or cavity-backed slot antenn...

  12. 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.

  13. 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

  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. 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...

  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. Field Simulation in GTEM Cell Work Area Based on FDTD%基于FDTD对GHZ横电磁波室工作区的场强仿真

    Institute of Scientific and Technical Information of China (English)

    于晓峰; 邹澎

    2011-01-01

    It is difficult to accurately analyze field distribution in GTEM Cell due to indoor propagation of electromagnetic waves occurs in the reflection, diffraction, scattering, absorption and other phenomena when radiation experiments in GTEM Cell. Place a glass box which is for study in the small work area of GTEM Cell , then, import the three-dimensional model with the use of AutoCAD 2008 into XFDTD software based on FDTD (finite diffence time domain), afterwards , start simulation, and get field distribution of glass box. Finally, it is proves that the field of the glass box under the condition of 1.8 GHz, 140 dBμV/m is uniform, and heterogeneity of not more than ± 2 dB, and reach the requirements of biomedical experiments.%在GHz横电磁波室内进行辐射实验时,由于电磁波在室内传播会发生反射、绕射、散射、吸收等现象,导致了很难精确地分析GHz横电磁波室内的场强.以放置在GHz横电磁波室小工作区内的玻璃箱为研究对象,利用AutoCAD 2008建立三维模型,导入基于FDTD(时域有限差分法)的XFDTD软件进行仿真,得到玻璃箱的场强分布.最后通过对比分析仿真数据与实际测量数据,证明了玻璃箱内的场强在1.8 GHz、140dBμV/m的条件下是均匀电磁场,而且不均匀性不超过±2 dB,达到了生物医学实验的要求.该仿真为高精度、高速度地计算室内复杂的电磁场问题提供了一种新的方法.

  1. The ADI-FDTD method for high accuracy electrophysics applications

    Science.gov (United States)

    Haeri Kermani, Mohammad

    The Finite-Difference Time-Domain (FDTD) is a dependable method to simulate a wide range of problems from acoustics, to electromagnetics, and to photonics, amongst others. The execution time of an FDTD simulation is inversely proportional to the time-step size. Since the FDTD method is explicit, its time-step size is limited by the well-known Courant-Friedrich-Levy (CFL) stability limit. The CFL stability limit can render the simulation inefficient for very fine structures. The Alternating Direction Implicit FDTD (ADI-FDTD) method has been introduced as an unconditionally stable implicit method. Numerous works have shown that the ADI-FDTD method is stable even when the CFL stability limit is exceeded. Therefore, the ADI-FDTD method can be considered an efficient method for special classes of problems with very fine structures or high gradient fields. Whenever the ADI-FDTD method is used to simulate open-region radiation or scattering problems, the implementation of a mesh-truncation scheme or absorbing boundary condition becomes an integral part of the simulation. These truncation techniques represent, in essence, differential operators that are discretized using a distinct differencing scheme which can potentially affect the stability of the scheme used for the interior region. In this work, we show that the ADI-FDTD method can be rendered unstable when higher-order mesh truncation techniques such as Higdon's Absorbing Boundary Condition (ABC) or Complementary Derivatives Method (COM) are used. When having large field gradients within a limited volume, a non-uniform grid can reduce the computational domain and, therefore, it decreases the computational cost of the FDTD method. However, for high-accuracy problems, different grid sizes increase the truncation error at the boundary of domains having different grid sizes. To address this problem, we introduce the Complementary Derivatives Method (CDM), a second-order accurate interpolation scheme. The CDM theory is

  2. 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

  3. Agent-based simulation of animal behaviour

    NARCIS (Netherlands)

    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 DES

  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. 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.

  6. 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.

  7. Model and analysis on electromagnetic radiation of flyback power supply by FDTD simulation%反激式变换器电磁辐射的FDTD仿真与分析

    Institute of Scientific and Technical Information of China (English)

    赵全斌; 付琦; 和军平

    2011-01-01

    Electromagnetic radiation emission from a switched mode power supply is easily exceeding EMC standard limits and this phenomenon is difficult to debug for many switched mode power supply designers. It is very necessa ry to study electromagnetic radiation mechanism, characteristics and prediction method for industrial community and academia. After analyzing and modeling of some active and reactive components, such as capacitor, transformer, diode, MOSFET, PCB traces, input/output cords, a FDTD model of a flyback SMPS is set up. The distribution pattern and magnitude characteristics of far-field electromagnetic radiation are simulated and analyzed based on X FDTD software. Using simulation tool, it is found that input and output cables have a significant influence on the far-field electromagnetic radiation distribution of the flyback power supply in 30MHz-300MHz. The capability of a common mode EMI choke to inhibit radiation is verified by using simulation. This paper is useful for SMPS engi neers to design and decrease far-field electromagnetic radiation.%开关电源电磁辐射发射容易超出EMC标准限值,有必要对其形成机理、特性和预测进行研究.本文在建立电容、变压器、PCB引线、半导体开关等元器件模型基础上,对Flyback开关电源进行了时域有限差分(FDTD)建模,仿真研究了其在开放空间中远场电磁辐射的分布和规律.仿真结果表明开关电源输入/输出电缆是电磁辐射的主要影响因素,并验证了共模电感对远场电磁辐射的抑制作用.

  8. Enhancements to FDTD modeling for optical metrology applications

    Science.gov (United States)

    Salski, Bartlomiej; Celuch, Malgorzata; Gwarek, Wojciech

    2007-06-01

    This paper presents Finite Difference Time Domain (FDTD) method based on discretised Maxwell curl equations and widely used in microwave circuit design - as a promising tool for new optical metrology purposes. We focus on periodic FDTD formulations for scattering problems. The interest in efficient full-wave modelling of periodic structures has arisen due to their increasing applications as slow wave transmission lines, photonic crystals, and metamaterials. Recently, new efforts have been made to incorporate the FDTD algorithms into the scatterometry overlay technology (SCOL) toolkit. In SCOL, multilayered grating targets on silicon wafers are illuminated with polarised light at a particular angle of incidence; reflected signal of the 0 th diffraction order is processed to extract the information about misalignment between grating layers. Since the illumination spot size typically covers tens or even hundreds of grating periods, direct 3D FDTD modelling of such an electrically large problem needs long computing times. The periodic FDTD algorithm discussed herein, built upon Floquet theorem, allows reduction of the modelling problem to one or just a few periods. As a consequence, it substantially speeds up the simulation. The incident wave is modelled as a plane wave. The reflected wave is extracted via near-to-far (NTF) transformation as in antenna analysis. We cross-calibrate the FDTD algorithm against other numerical techniques better established in optical metrology, like Rigorous Coupled Wave Analysis (RCWA). For a benchmark of multilayered rectangular grating composition illuminated with light within the 500 to 700 nm spectrum, we show that the FDTD and RCWA results for the 0 th diffraction order reflection coefficient are in excellent agreement. The FDTD approach is more flexible as it further allows quantitative characterisation of non-rectangular periodic structures, higher-order diffraction rays, and periodicity violation. This work was done in the

  9. Study on FDTD-SPICE Co-simulation Technique%基于FDTD与SPICE的协同仿真分析方法

    Institute of Scientific and Technical Information of China (English)

    周晓明; 刘伟; 张小斌

    2009-01-01

    为了在进行高速电路的分析时能够发挥FDTD与SPICE各自的优势,提出一种将FDTD与SPICE相结合的协同仿真方法.该方法的特点是用FDTD来计算互连部分,而接在互连网络终端的元器件通过SPICE来计算,二者在元件与互连线相连接的端口上进行计算数据的通信.介绍了FDTD-SPICE方法的基本原理和计算流程,并以比较器电路为例详细讨论FDTD-SPICE协同仿真分析的方法的全过程.

  10. 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.

  11. 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...

  12. 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

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

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Tuchin, Valery; Pond, James

    2010-01-01

    In this paper we focus on the discussion of two recent unique applications of the Finite-Difference Time-Domain (FDTD) simulation method to the design and modeling of advanced nano- and bio-photonic problems. The approach that is adopted here focuses on the potential of the FDTD methodology to ad...... 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....

  14. 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...

  15. 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

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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 ...

  4. 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

  5. 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...

  6. 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 ...

  7. MAIA: a framework for developing agent-based social simulations

    NARCIS (Netherlands)

    Ghorbani, Amineh; Dignum, Virginia; Bots, Pieter; Dijkema, Gerhard

    2013-01-01

    In this paper we introduce and motivate a conceptualization framework for agent-based social simulation, MAIA: Modelling Agent systems based on Institutional Analysis. The MAIA framework is based on Ostrom's Institutional Analysis and Development framework, and provides an extensive set of modelling

  8. 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.

  9. A new model of dispersion for metals leading to a more accurate modeling of plasmonic structures using the FDTD method

    Energy Technology Data Exchange (ETDEWEB)

    Vial, A.; Dridi, M.; Cunff, L. le [Universite de Technologie de Troyes, Institut Charles Delaunay, CNRS UMR 6279, Laboratoire de Nanotechnologie et d' Instrumentation Optique, 12, rue Marie Curie, BP-2060, Troyes Cedex (France); Laroche, T. [Universite de Franche-Comte, Institut FEMTO-ST, CNRS UMR 6174, Departement de Physique et de Metrologie des Oscillateurs, Besancon Cedex (France)

    2011-06-15

    We present FDTD simulations results obtained using the Drude critical points model. This model enables spectroscopic studies of metallic structures over wider wavelength ranges than usually used, and it facilitates the study of structures made of several metals. (orig.)

  10. Brahms An Agent-Oriented Language for Work Practice Simulation and Multi-Agent Systems Development

    Science.gov (United States)

    Sierhuis, Maarten; Clancey, William J.; van Hoof, Ron J. J.

    Brahms is a multi-agent modeling language for simulating human work practice that emerges from work processes in organizations. The same Brahms language can be used to implement and execute distributed multi-agent systems, based on models of work practice that were first simulated. Brahms demonstrates how a multi-agent belief-desire-intention language, symbolic cognitive modeling, traditional business process modeling, activity-and situated cognition theories are brought together in a coherent approach for analysis and design of organizations and human-centered systems.

  11. Evaluating the STORE Reputation System in Multi-Agent Simulations

    Science.gov (United States)

    Andrulis, Jonas; Haller, Jochen; Weinhardt, Christof; Karabulut, Yuecel

    In recent global business environments, collaborations among organisations raise an increased demand for swift establishment. Such collaborations are formed between organisations entering Virtual Organizations (VOs), crossing geographic borders and frequently without prior experience of the other partner’s previous performance. In VOs, every participant risks engaging with partners who may exhibit unexpected fraudulent or otherwise untrusted behaviour. In order to cope with this risk, the STochastic REputation system (STORE) was designed to provide swift, automated decision support for selecting partner organisations in the early stages of the VO’s formation. The contribution of this paper first consists of a multi-agent simulation framework design and implementation to evaluate the STORE reputation system. This framework is able to simulate dynamic agent behaviour, agents hereby representing organisations, and to capture the business context of different VO application scenarios. A configuration of agent classes is a powerful tool to obtain not only well or badly performing agents for simulation scenarios, but also agents which are specialized in particular VO application domains or even malicious agents, attacking the VO community. The second contribution comprises of STORE’s evaluation in two simulation scenarios, set in the VO application domains of Collaborative Engineering and Ad-hoc Service provisioning. Besides the ability to clearly distinguish between agents of different classes according to their reputation, the results prove STORE’s ability to take an agent’s dynamic behaviour into account. The simulation results show, that STORE solves the difficult task of selecting the most trustworthy partner for a particular VO application domain from a set of honest agents that are specialized in a wide spread of VO application domains.

  12. Agent-based simulation of animal behaviour

    NARCIS (Netherlands)

    Jonker, C.M.; Treur, J.

    2001-01-01

    In the biological literature on animal behaviour, in addition to real experiments and field studies, also simulation experiments are a useful source of progress. Often specific mathematical modelling techniques are adopted and directly implemented in a programming language. Modelling more complex ag

  13. 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

  14. 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

  15. 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.

  16. 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%.

  17. 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.

    2016-09-01

    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%.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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

  6. 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...

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.)

  1. 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.

  2. 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.

  3. 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.

  4. Validation techniques of agent based modelling for geospatial simulations

    Science.gov (United States)

    Darvishi, M.; Ahmadi, G.

    2014-10-01

    One of the most interesting aspects of modelling and simulation study is to describe the real world phenomena that have specific properties; especially those that are in large scales and have dynamic and complex behaviours. Studying these phenomena in the laboratory is costly and in most cases it is impossible. Therefore, Miniaturization of world phenomena in the framework of a model in order to simulate the real phenomena is a reasonable and scientific approach to understand the world. Agent-based modelling and simulation (ABMS) is a new modelling method comprising of multiple interacting agent. They have been used in the different areas; for instance, geographic information system (GIS), biology, economics, social science and computer science. The emergence of ABM toolkits in GIS software libraries (e.g. ESRI's ArcGIS, OpenMap, GeoTools, etc) for geospatial modelling is an indication of the growing interest of users to use of special capabilities of ABMS. Since ABMS is inherently similar to human cognition, therefore it could be built easily and applicable to wide range applications than a traditional simulation. But a key challenge about ABMS is difficulty in their validation and verification. Because of frequent emergence patterns, strong dynamics in the system and the complex nature of ABMS, it is hard to validate and verify ABMS by conventional validation methods. Therefore, attempt to find appropriate validation techniques for ABM seems to be necessary. In this paper, after reviewing on Principles and Concepts of ABM for and its applications, the validation techniques and challenges of ABM validation are discussed.

  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. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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 ...

  14. Investigating Output Accuracy for a Discrete Event Simulation Model and an Agent Based Simulation Model

    CERN Document Server

    Majid, Mazlina Abdul; Siebers, Peer-Olaf

    2010-01-01

    In this paper, we investigate output accuracy for a Discrete Event Simulation (DES) model and Agent Based Simulation (ABS) model. The purpose of this investigation is to find out which of these simulation techniques is the best one for modelling human reactive behaviour in the retail sector. In order to study the output accuracy in both models, we have carried out a validation experiment in which we compared the results from our simulation models to the performance of a real system. Our experiment was carried out using a large UK department store as a case study. We had to determine an efficient implementation of management policy in the store's fitting room using DES and ABS. Overall, we have found that both simulation models were a good representation of the real system when modelling human reactive behaviour.

  15. A postprocessing method based on high-resolution spectral estimation for FDTD calculation of phononic band structures

    Energy Technology Data Exchange (ETDEWEB)

    Su Xiaoxing, E-mail: xxsu@bjtu.edu.c [School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li Jianbao; Wang Yuesheng [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China)

    2010-05-15

    If the energy bands of a phononic crystal are calculated by the finite difference time domain (FDTD) method combined with the fast Fourier transform (FFT), good estimation of the eigenfrequencies can only be ensured by the postprocessing of sufficiently long time series generated by a large number of FDTD iterations. In this paper, a postprocessing method based on the high-resolution spectral estimation via the Yule-Walker method is proposed to overcome this difficulty. Numerical simulation results for three-dimensional acoustic and two-dimensional elastic systems show that, compared with the classic FFT-based postprocessing method, the proposed method can give much better estimation of the eigenfrequencies when the FDTD is run with relatively few iterations.

  16. 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

  17. 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...

  18. 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.

  19. 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.

  20. FDTD Computation of Scattering by Buried Objects

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-yan; SHENG Xin-qing

    2007-01-01

    A computational approach of scattering by buried objects is presented by using finite-difference time-domain (FDTD) method, the uniaxial perfectly matched layer (UPML), and reciprocity theorem. The numerical performance of this approach is investigated by numerical experiments. The radar cross sections (RCS) of various buried objects with different electrical sizes, shapes, dielectric constants, are computed and analyzed. The results show that for the conducting cube, the RCS curves are fluctuant, but for the sphere shape one, the curves are smooth. Comparing with scattering in the free space, the ground greatly affects the RCS by dielectric targets, but little does by conducting targets. For the buried dielectric objects, iterative steps can be evaluated by four to five round-trip traversals of the Huygens box, but for the conducting ones, the time steps can be reduced to three round-trip traversals. When the ground is lossy, the run-time can be reduced more to two round-trip traversals.

  1. Reactive Planning Simulation in Dynamic Environments with VirtualRobot: Reactive agents and Simulation

    Directory of Open Access Journals (Sweden)

    Arefeh Esalat Nejad

    2014-05-01

    Full Text Available In real-world environments such in air combat missions the agents continuously receive perceptual inputs from the environment that is highly dynamic (unpredictable and uncertain. The aircraft often have to reorganise themselves and to make decisions under time constraints. Two modes of control are thus necessary: planning and reaction. By planning we mean both building a course of action before execution, and reaction as dynamic replanning which interleaves planning and execution. Furthermore, in air combat simulation the plans adopted by the agents in response to external events are known in advance and are not generated by the agents as in other domains. To be reactive, the agents have to choose dynamically the appropriate plans and to coordinate their actions. We present how we take into account new events thanks to dynamic allocation of tasks by model of tasks and goals by integrating time notions in the selection of action plans and coordinate mechanisms. Operations on plans under time constraints are also examined in order to enable the simultaneous management of several events. The whole system is integrated into VirtualRobot, a graphical software application, which provides a flexible and open platform to work on robotics. Through VirtualRobot we can incorporate important features into the system as simulation of sensing actions or a monitoring mechanism. Additionally, the planning algorithm is able to work in timelimited situations and use numeric variables. All these features make our planningsystem be a nice toolkit to deal with reactive robot planning

  2. 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

  3. 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.

    2016-08-01

    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.

  4. A More Accurate, Stable, FDTD Algorithm for Electromagnetics in Anisotropic Dielectrics

    CERN Document Server

    Werner, Gregory R; Cary, John R

    2012-01-01

    A more accurate, stable, finite-difference time-domain (FDTD) algorithm is developed for simulating Maxwell's equations with isotropic or anisotropic dielectric materials. This algorithm is in many cases more accurate than previous algorithms (G. R. Werner et. al., 2007; A. F. Oskooi et. al., 2009), and it remedies a defect that causes instability with high dielectric contrast (usually for \\epsilon{} significantly greater than 10) with either isotropic or anisotropic dielectrics. Ultimately this algorithm has first-order error (in the grid cell size) when the dielectric boundaries are sharp, due to field discontinuities at the dielectric interface. Accurate treatment of the discontinuities, in the limit of infinite wavelength, leads to an asymmetric, unstable update (C. A. Bauer et. al., 2011), but the symmetrized version of the latter is stable and more accurate than other FDTD methods. The convergence of field values supports the hypothesis that global first-order error can be achieved by second-order error...

  5. 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.

  6. 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,...

  7. 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

  8. 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).…

  9. 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.

  10. Calculation of light delay for coupled microrings by FDTD technique and Padé approximation.

    Science.gov (United States)

    Huang, Yong-Zhen; Yang, Yue-De

    2009-11-01

    The Padé approximation with Baker's algorithm is compared with the least-squares Prony method and the generalized pencil-of-functions (GPOF) method for calculating mode frequencies and mode Q factors for coupled optical microdisks by FDTD technique. Comparisons of intensity spectra and the corresponding mode frequencies and Q factors show that the Padé approximation can yield more stable results than the Prony and the GPOF methods, especially the intensity spectrum. The results of the Prony method and the GPOF method are greatly influenced by the selected number of resonant modes, which need to be optimized during the data processing, in addition to the length of the time response signal. Furthermore, the Padé approximation is applied to calculate light delay for embedded microring resonators from complex transmission spectra obtained by the Padé approximation from a FDTD output. The Prony and the GPOF methods cannot be applied to calculate the transmission spectra, because the transmission signal obtained by the FDTD simulation cannot be expressed as a sum of damped complex exponentials.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  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. 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.

  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. 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 (...

  20. 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

    2016-08-24

    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.

  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. 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.

  3. 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.

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

    NARCIS (Netherlands)

    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 si

  5. 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.

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. Agent-based analysis and simulation of meta-reasoning processes in strategic naval planning

    NARCIS (Netherlands)

    Hoogendoorn, M.; Jonker, C.M.; Maanen, P.P. van; Treur, J.

    2009-01-01

    This paper presents analysis and simulation of meta-reasoning processes based on an agent-based meta-level architecture for strategic reasoning in naval planning. The architecture was designed as a generic agent model and instantiated with decision knowledge acquired from naval domain experts and wa

  11. Land-use change arising from rural land exchange : an agent-based simulation model

    NARCIS (Netherlands)

    Bakker, Martha M.; Alam, Shah Jamal; van Dijk, Jerry; Rounsevell, Mark D. A.

    2015-01-01

    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing farmer

  12. 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...

  13. 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.``

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. Performance analysis of the FDTD method applied to holographic volume gratings: Multi-core CPU versus GPU computing

    Science.gov (United States)

    Francés, J.; Bleda, S.; Neipp, C.; Márquez, A.; Pascual, I.; Beléndez, A.

    2013-03-01

    The finite-difference time-domain method (FDTD) allows electromagnetic field distribution analysis as a function of time and space. The method is applied to analyze holographic volume gratings (HVGs) for the near-field distribution at optical wavelengths. Usually, this application requires the simulation of wide areas, which implies more memory and time processing. In this work, we propose a specific implementation of the FDTD method including several add-ons for a precise simulation of optical diffractive elements. Values in the near-field region are computed considering the illumination of the grating by means of a plane wave for different angles of incidence and including absorbing boundaries as well. We compare the results obtained by FDTD with those obtained using a matrix method (MM) applied to diffraction gratings. In addition, we have developed two optimized versions of the algorithm, for both CPU and GPU, in order to analyze the improvement of using the new NVIDIA Fermi GPU architecture versus highly tuned multi-core CPU as a function of the size simulation. In particular, the optimized CPU implementation takes advantage of the arithmetic and data transfer streaming SIMD (single instruction multiple data) extensions (SSE) included explicitly in the code and also of multi-threading by means of OpenMP directives. A good agreement between the results obtained using both FDTD and MM methods is obtained, thus validating our methodology. Moreover, the performance of the GPU is compared to the SSE+OpenMP CPU implementation, and it is quantitatively determined that a highly optimized CPU program can be competitive for a wider range of simulation sizes, whereas GPU computing becomes more powerful for large-scale simulations.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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 ...

  6. 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...

  7. 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...

  8. 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.

  9. Market power analysis in the EEX electricity market : an agent-based simulation approach.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Botterud, A.; Conzelmann, G.; Koritarov, V.; Decision and Information Sciences

    2008-01-01

    In this paper, an agent-based modeling and simulation (ABMS) approach is used to model the German wholesale electricity market. The spot market prices in the European Energy Exchange (EEX) are studied as the wholesale market prices. Each participant in the market is modeled as an individual rationality-bounded agent whose objective is to maximize its own profit. By simulating the market clearing process, the interaction among agents is captured. The market clearing price formed by agentspsila production cost bidding is regarded as the reference marginal cost. The gap between the marginal cost and the real market price is measured as an indicator of possible market power exertion. Various bidding strategies such as physical withholding and economic withholding can be simulated to represent strategic bidding behaviors of the market participants. The preliminary simulation results show that some generation companies (GenCos) are in the position of exerting market power by strategic bidding.

  10. 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

    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.

  11. 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...

  12. 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%.

  13. 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.

  14. With us or against us: simulated social touch by virtual agents in a cooperative or competitive setting

    NARCIS (Netherlands)

    Huisman, Gijs; Kolkmeier, Jan; Heylen, Dirk; Bickmore, Timothy; Marsella, Stacy; Sidner, Candance

    2014-01-01

    In this paper we examine how simulated social touch by a virtual agent in a cooperative or competitive augmented reality game influences the perceived trustworthiness, warmth and politeness of the agent. Before and after the game, participants interact with two agents whereby one agent touches the p

  15. 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.

  16. 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...

  17. 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....

  18. 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...

  19. 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...

  20. 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

  1. 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.

  2. 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...

  3. 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.

  4. 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 .

  5. 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.

  6. 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。

  7. 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...

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

    Science.gov (United States)

    Tan, L.; Lin, H.; Hu, M.; Che, W.

    2014-02-01

    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.

  9. 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

  10. 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...

  11. 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...

  12. 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...... resources, so that realistic scenarios with palpable influence on real resources can be simulated. The SG simulator is also connected to the Multi-Agent Simulator of Competitive Electricity Markets (MASCEM), which provides a solid framework for the simulation of restructured electricity markets. Taking...... advantage on the complementarities between the simulators, a SG market is proposed, and a realistic simulation scenario, using two real buildings acting in a simulated SG is presented....

  13. 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.

  14. 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.

  15. Design and simulation of material-integrated distributed sensor processing with a code-based agent platform and mobile multi-agent systems.

    Science.gov (United States)

    Bosse, Stefan

    2015-01-01

    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.

  16. 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.

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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

  3. 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.

  4. Extension of FDTD absorbing boundary condition methods to lossy dielectrics for the modeling of microwave devices

    Science.gov (United States)

    Wittwer, David Christian

    The finite difference time domain (FDTD) method has become a main stream analysis tool for engineers solving complex electromagnetic wave interaction problems. Its first principles approach affords it a wide range of applications from radar cross section (RCS) predictions of electrically large structures to molecular scale analysis of complex materials. This wide area of application may be attributed to the coupling of auxiliary differential equations with Maxwell's equations to describe the physical properties of a given problem. Previous extensions have included sub-cell models for describing lumped circuit elements within a single Yee cell, transformation of near-field information to the far-field for the analysis of antenna problems, dispersive material models and mesh truncation techniques. A review of these extensions is presented. What has not been previously developed is the ability to truncate lossy dielectric materials at the boundary of the simulation domain. Such outer boundary conditions (OBCs) are required in simulations dealing with ground penetrating radar, integrated circuits and many microwave devices such as stripline and microstrip structures. We have developed such an OBC by surrounding the exterior of the simulation domain with a lossy dispersive material based on a two time-derivative Lorentz model (L2TDLM). We present the development of the material as an absorber and ultimately as a full 3D OBC. Examples of microstrip, structures are presented to re-enforce the importance of modeling losses in dielectric structures. Finally, validation of the FDTD simulator and demonstration of the L2TDLM OBC's effectiveness is achieved by comparison with measured results from these microwave devices.

  5. 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

  6. 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.

  7. 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...... can be applied to quantitation of perfusion, functional MRI and vessel size imaging...

  8. 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.

  9. 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.

  10. 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

  11. 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...

  12. 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.

  13. 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.

  14. Simulation of ethanol extractive distillation with mixed glycols as separating agent

    Directory of Open Access Journals (Sweden)

    I. D. Gil

    2014-03-01

    Full Text Available Extractive distillation is an alternative for ethanol dehydration processes that has been shown to be more effective than azeotropic distillation and, in close proximity, to be very competitive against the process that uses adsorption with molecular sieves. Glycols have been shown to be the most effective solvents in extractive distillation, mainly ethylene glycol and glycerol. In this work, an extractive distillation column was simulated with the Aspen Plus software platform, using the RadFrac module for distillation columns, to investigate the effect on the separation of the ethylene glycol-glycerol mixture composition, the separating agent feed stages, the separating agent split stream feed, and the azeotropic feed temperature. The NRTL model was used to calculate the phase equilibrium of these strongly polar mixtures. A rigorous simulation of the extractive distillation column finally established was also performed, including a secondary recovery column for the mixture of solvents and a recycle loop, to simulate an industrially relevant situation. This simulation allowed establishing the complete parameters to dehydrate ethanol: the optimal stage for separating agent feed is stage 4; the most adequate composition for the glycols mixture is 60 mol% ethylene glycol and 40 mol% glycerol. Finally, energetically efficient operating conditions for each one of the columns were established through a preliminary pinch analysis.

  15. 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.

  16. Agent Based Simulation of Group Emotions Evolution and Strategy Intervention in Extreme Events

    Directory of Open Access Journals (Sweden)

    Bo Li

    2014-01-01

    Full Text Available Agent based simulation method has become a prominent approach in computational modeling and analysis of public emergency management in social science research. The group emotions evolution, information diffusion, and collective behavior selection make extreme incidents studies a complex system problem, which requires new methods for incidents management and strategy evaluation. This paper studies the group emotion evolution and intervention strategy effectiveness using agent based simulation method. By employing a computational experimentation methodology, we construct the group emotion evolution as a complex system and test the effects of three strategies. In addition, the events-chain model is proposed to model the accumulation influence of the temporal successive events. Each strategy is examined through three simulation experiments, including two make-up scenarios and a real case study. We show how various strategies could impact the group emotion evolution in terms of the complex emergence and emotion accumulation influence in extreme events. This paper also provides an effective method of how to use agent-based simulation for the study of complex collective behavior evolution problem in extreme incidents, emergency, and security study domains.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Simulating the Reproductive Behavior of a Region’s Population with an Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Valeriy Leonidovich Makarov

    2015-09-01

    Full Text Available The research analyses the impact of the inequality of demographic transition on socio-demographic characteristics of the regional population and on the dynamics of these characteristics. The study was conducted with the help of computer-based experiments (simulations, which was run on the original agent-based model. The model is an artificial society, and personal characteristics of its members are set so that they could represent age-demographic structure of a simulate region. The agents are divided into two subgroups, which differ in their reproductive strategy. The first group has traditional strategy with high birth rate. The second group has considerably lower birth rate, observed in the modern developed societies. The model uses stochastic approaches to imitate the principle processes of population growth: mortality and morbidity. Mortality is set according to age-sex specific mortality coefficients, which do not differ across the population as a whole. New agents (child births appear as a choice of agents – women of reproductive age, and the choice depends on the subgroup. The overall age and social structure of the region is aggregated across individual agents. A number of experiments has been carried out with the model utilization. This allowed forecasting the size and structure of the population of a given region. The results of the experiments have revealed that despite its simplicity, the developed agent-based model well predicts the initial conditions in the region (e.g. age-demographic and social structure. The model shows good fit in terms of estimating the dynamics of major characteristics of the population.

  2. 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.

  3. 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...... application in electricity markets can prove to be a high potential tool. This paper proposes a new scenario analysis algorithm, which includes the application of game-theory, to evaluate and preview different scenarios and provide players with the ability to strategically react in order to exhibit...... 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...

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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.

  13. 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...

  14. 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...

  15. 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.

  16. 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.

  17. Quantitative agent-based firm dynamics simulation with parameters estimated by financial and transaction data analysis

    Science.gov (United States)

    Ikeda, Yuichi; Souma, Wataru; Aoyama, Hideaki; Iyetomi, Hiroshi; Fujiwara, Yoshi; Kaizoji, Taisei

    2007-03-01

    Firm dynamics on a transaction network is considered from the standpoint of econophysics, agent-based simulations, and game theory. In this model, interacting firms rationally invest in a production facility to maximize net present value. We estimate parameters used in the model through empirical analysis of financial and transaction data. We propose two different methods ( analytical method and regression method) to obtain an interaction matrix of firms. On a subset of a real transaction network, we simulate firm's revenue, cost, and fixed asset, which is the accumulated investment for the production facility. The simulation reproduces the quantitative behavior of past revenues and costs within a standard error when we use the interaction matrix estimated by the regression method, in which only transaction pairs are taken into account. Furthermore, the simulation qualitatively reproduces past data of fixed assets.

  18. 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

  19. 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

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    Voinea, Camelia Florela

    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.  

  2. 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.

  3. 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...

  4. 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.

  5. 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...

  6. Automated multi-objective calibration of biological agent-based simulations.

    Science.gov (United States)

    Read, Mark N; Alden, Kieran; Rose, Louis M; Timmis, Jon

    2016-09-01

    Computational agent-based simulation (ABS) is increasingly used to complement laboratory techniques in advancing our understanding of biological systems. Calibration, the identification of parameter values that align simulation with biological behaviours, becomes challenging as increasingly complex biological domains are simulated. Complex domains cannot be characterized by single metrics alone, rendering simulation calibration a fundamentally multi-metric optimization problem that typical calibration techniques cannot handle. Yet calibration is an essential activity in simulation-based science; the baseline calibration forms a control for subsequent experimentation and hence is fundamental in the interpretation of results. Here, we develop and showcase a method, built around multi-objective optimization, for calibrating ABSs against complex target behaviours requiring several metrics (termed objectives) to characterize. Multi-objective calibration (MOC) delivers those sets of parameter values representing optimal trade-offs in simulation performance against each metric, in the form of a Pareto front. We use MOC to calibrate a well-understood immunological simulation against both established a priori and previously unestablished target behaviours. Furthermore, we show that simulation-borne conclusions are broadly, but not entirely, robust to adopting baseline parameter values from different extremes of the Pareto front, highlighting the importance of MOC's identification of numerous calibration solutions. We devise a method for detecting overfitting in a multi-objective context, not previously possible, used to save computational effort by terminating MOC when no improved solutions will be found. MOC can significantly impact biological simulation, adding rigour to and speeding up an otherwise time-consuming calibration process and highlighting inappropriate biological capture by simulations that cannot be well calibrated. As such, it produces more accurate

  7. Automated multi-objective calibration of biological agent-based simulations.

    Science.gov (United States)

    Read, Mark N; Alden, Kieran; Rose, Louis M; Timmis, Jon

    2016-09-01

    Computational agent-based simulation (ABS) is increasingly used to complement laboratory techniques in advancing our understanding of biological systems. Calibration, the identification of parameter values that align simulation with biological behaviours, becomes challenging as increasingly complex biological domains are simulated. Complex domains cannot be characterized by single metrics alone, rendering simulation calibration a fundamentally multi-metric optimization problem that typical calibration techniques cannot handle. Yet calibration is an essential activity in simulation-based science; the baseline calibration forms a control for subsequent experimentation and hence is fundamental in the interpretation of results. Here, we develop and showcase a method, built around multi-objective optimization, for calibrating ABSs against complex target behaviours requiring several metrics (termed objectives) to characterize. Multi-objective calibration (MOC) delivers those sets of parameter values representing optimal trade-offs in simulation performance against each metric, in the form of a Pareto front. We use MOC to calibrate a well-understood immunological simulation against both established a priori and previously unestablished target behaviours. Furthermore, we show that simulation-borne conclusions are broadly, but not entirely, robust to adopting baseline parameter values from different extremes of the Pareto front, highlighting the importance of MOC's identification of numerous calibration solutions. We devise a method for detecting overfitting in a multi-objective context, not previously possible, used to save computational effort by terminating MOC when no improved solutions will be found. MOC can significantly impact biological simulation, adding rigour to and speeding up an otherwise time-consuming calibration process and highlighting inappropriate biological capture by simulations that cannot be well calibrated. As such, it produces more accurate

  8. EM modeling for GPIR using 3D FDTD modeling codes

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, S.D.

    1994-10-01

    An analysis of the one-, two-, and three-dimensional electrical characteristics of structural cement and concrete is presented. This work connects experimental efforts in characterizing cement and concrete in the frequency and time domains with the Finite Difference Time Domain (FDTD) modeling efforts of these substances. These efforts include Electromagnetic (EM) modeling of simple lossless homogeneous materials with aggregate and targets and the modeling dispersive and lossy materials with aggregate and complex target geometries for Ground Penetrating Imaging Radar (GPIR). Two- and three-dimensional FDTD codes (developed at LLNL) where used for the modeling efforts. Purpose of the experimental and modeling efforts is to gain knowledge about the electrical properties of concrete typically used in the construction industry for bridges and other load bearing structures. The goal is to optimize the performance of a high-sample-rate impulse radar and data acquisition system and to design an antenna system to match the characteristics of this material. Results show agreement to within 2 dB of the amplitudes of the experimental and modeled data while the frequency peaks correlate to within 10% the differences being due to the unknown exact nature of the aggregate placement.

  9. 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.

  10. 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...

  11. A Multi-agent Simulation Tool for Micro-scale Contagion Spread Studies

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Daniel B [ORNL

    2016-01-01

    Within the disaster preparedness and emergency response community, there is interest in how contagions spread person-to-person at large gatherings and if mitigation strategies can be employed to reduce new infections. A contagion spread simulation module was developed for the Incident Management Preparedness and Coordination Toolkit that allows a user to see how a geographically accurate layout of the gathering space helps or hinders the spread of a contagion. The results can inform mitigation strategies based on changing the physical layout of an event space. A case study was conducted for a particular event to calibrate the underlying simulation model. This paper presents implementation details of the simulation code that incorporates agent movement and disease propagation. Elements of the case study are presented to show how the tool can be used.

  12. 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.

  13. 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.

  14. A Multi-Agent Approach to the Simulation of Robotized Manufacturing Systems

    Science.gov (United States)

    Foit, K.; Gwiazda, A.; Banaś, W.

    2016-08-01

    The recent years of eventful industry development, brought many competing products, addressed to the same market segment. The shortening of a development cycle became a necessity if the company would like to be competitive. Because of switching to the Intelligent Manufacturing model the industry search for new scheduling algorithms, while the traditional ones do not meet the current requirements. The agent-based approach has been considered by many researchers as an important way of evolution of modern manufacturing systems. Due to the properties of the multi-agent systems, this methodology is very helpful during creation of the model of production system, allowing depicting both processing and informational part. The complexity of such approach makes the analysis impossible without the computer assistance. Computer simulation still uses a mathematical model to recreate a real situation, but nowadays the 2D or 3D virtual environments or even virtual reality have been used for realistic illustration of the considered systems. This paper will focus on robotized manufacturing system and will present the one of possible approaches to the simulation of such systems. The selection of multi-agent approach is motivated by the flexibility of this solution that offers the modularity, robustness and autonomy.

  15. 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.

  16. 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).

  17. 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).

  18. 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)

  19. 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.

  20. 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.

  1. 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

  2. An agent-based epidemic simulation of social behaviors affecting HIV transmission among Taiwanese homosexuals.

    Science.gov (United States)

    Huang, Chung-Yuan

    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 links-are used to indicate tendencies among individuals who either have large numbers of short-term partners or stay in long-term monogamous relationships. An attempt was made to reproduce epidemic curves of reported HIV cases among male homosexuals in Taiwan prior to using the agent-based model to determine the effects of various policies on epidemic dynamics. Results suggest that when suitable adjustments are made based on available social survey statistics, the model accurately simulates real-world behaviors on a large scale.

  3. 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 ...

  4. 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...

  5. 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.

  6. 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.

  7. 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...

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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)

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. An artificial intelligence approach for modeling molecular self-assembly: agent-based simulations of rigid molecules.

    Science.gov (United States)

    Fortuna, Sara; Troisi, Alessandro

    2009-07-23

    Agent-based simulations are rule-based models traditionally used for the simulations of complex systems. In this paper, an algorithm based on the concept of agent-based simulations is developed to predict the lowest energy packing of a set of identical rigid molecules. The agents are identified with rigid portions of the system under investigation, and they evolve following a set of rules designed to drive the system toward the lowest energy minimum. The algorithm is compared with a conventional Metropolis Monte Carlo algorithm, and it is applied on a large set of representative models of molecules. For all the systems studied, the agent-based method consistently finds a significantly lower energy minima than the Monte Carlo algorithm because the system evolution includes elements of adaptation (new configurations induce new types of moves) and learning (past successful choices are repeated).

  1. Efficient graph-based dynamic load-balancing for parallel large-scale agent-based traffic simulation

    NARCIS (Netherlands)

    Y. Xu; W. Cai; H. Aydt; M. Lees

    2014-01-01

    One of the issues of parallelizing large-scale agent-based traffic simulations is partitioning and load-balancing. Traffic simulations are dynamic applications where the distribution of workload in the spatial domain constantly changes. Dynamic load-balancing at run-time has shown better efficiency

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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 ...

  8. Dispersive Media Subcell Averaging in the FDTD Method using Corrective Surface Currents

    CERN Document Server

    Hamm, Joachim; Hess, Ortwin

    2013-01-01

    We present a corrective subcell averaging technique that improves on the accuracy of the volume-averaged finite-difference time-domain (FDTD) method in the presence of dispersive material interfaces. The method is based on an alternative effective-medium formulation that captures field discontinuities at interfaces as electric and magnetic surface currents. In calculating the spectra of strongly dispersive Mie scatterers we demonstrate that the derived FDTD algorithm is both highly efficient and able to approximately restore second order accuracy.

  9. 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

  10. 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.

  11. 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。

  12. Multi-Agent Modeling and Simulation Approach for Design and Analysis of MER Mission Operations

    Science.gov (United States)

    Seah, Chin; Sierhuis, Maarten; Clancey, William J.

    2005-01-01

    A space mission operations system is a complex network of human organizations, information and deep-space network systems and spacecraft hardware. As in other organizations, one of the problems in mission operations is managing the relationship of the mission information systems related to how people actually work (practices). Brahms, a multi-agent modeling and simulation tool, was used to model and simulate NASA's Mars Exploration Rover (MER) mission work practice. The objective was to investigate the value of work practice modeling for mission operations design. From spring 2002 until winter 2003, a Brahms modeler participated in mission systems design sessions and operations testing for the MER mission held at Jet Propulsion Laboratory (JPL). He observed how designers interacted with the Brahms tool. This paper discussed mission system designers' reactions to the simulation output during model validation and the presentation of generated work procedures. This project spurred JPL's interest in the Brahms model, but it was never included as part of the formal mission design process. We discuss why this occurred. Subsequently, we used the MER model to develop a future mission operations concept. Team members were reluctant to use the MER model, even though it appeared to be highly relevant to their effort. We describe some of the tool issues we encountered.

  13. Impact of road environment on drivers' behaviors in dilemma zone: Application of agent-based simulation.

    Science.gov (United States)

    Kim, Sojung; Son, Young-Jun; Chiu, Yi-Chang; Jeffers, Mary Anne B; Yang, C Y David

    2016-11-01

    At a signalized intersection, there exists an area where drivers become indecisive as to either stop their car or proceed through when the traffic signal turns yellow. This point, called a dilemma zone, has remained a safety concern for drivers due to the great possibility of a rear-end or right-angle crash occurring. In order to reduce the risk of car crashes at the dilemma zone, Institute of Transportation Engineers (ITE) recommended a dilemma zone model. The model, however, fails to provide precise calculations on the decision of drivers because it disregards the supplemental roadway information, such as whether a red light camera is present. Hence, the goal of this study was to incorporate such roadway environmental factors into a more realistic driver decision-making model for the dilemma zone. A driving simulator was used to determine the influence of roadway conditions on decision-making of real drivers. Following data collection, each driver's decision outcomes were implemented in an Agent-Based Simulation (ABS) so as to analyze behaviors under realistic road environments. The experimental results revealed that the proposed dilemma zone model was able to accurately predict the decisions of drivers. Specifically, the model confirmed the findings from the driving simulator study that the changes in the roadway environment reduced the number of red light violations at an intersection.

  14. 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.

  15. 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.

  16. 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).

  17. 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.

  18. 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.

  19. FDTD Application of Targets Electromagnetic Scattering in Layered Space

    Directory of Open Access Journals (Sweden)

    Jiang Yan-nan

    2013-07-01

    Full Text Available Finite Difference Time Domain (FDTD was used to characterize the electromagnetic scattering (EMS for targets in layered space. A new set of 1D modified Maxwell equations and auxiliary equations with incident angle was derived from 2D Maxwell equations and was used to compute the electromagnetic field in vertical boundary in 2D total field-scattered field (TF/SF, and thus incidence of uniform plane wave in time domain can be directly realized. In order to avoid complex Somerfield integration, the reciprocity theorem was used to simplify an extrapolation algorithm. Then the proposed algorithm and program in this paper were validated by applying them to compute the electromagnetic scattered field for targets in half-space and the radiation field for line current in layered lossy space. Finally this algorithm was used to characterize EMS for a tunnel in multi-layered space, for a tunnel open to vehicle, and for a tunnel and vehicle in lossless layered space. The results show the vehicle has a great impact on the scattering field, and the layered media surrounded the target can shield the scattering field.

  20. Towards Agent-Based Simulation of Emerging and Large-Scale Social Networks. Examples of the Migrant Crisis and MMORPGs

    Directory of Open Access Journals (Sweden)

    Schatten, Markus

    2016-10-01

    Full Text Available Large-scale agent based simulation of social networks is described in the context of the migrant crisis in Syria and the EU as well as massively multi-player on-line role playing games (MMORPG. The recipeWorld system by Terna and Fontana is proposed as a possible solution to simulating large-scale social networks. The initial system has been re-implemented using the Smart Python multi-Agent Development Environment (SPADE and Pyinteractive was used for visualization. We present initial models of simulation that we plan to develop further in future studies. Thus this paper is research in progress that will hopefully establish a novel agent-based modelling system in the context of the ModelMMORPG project.

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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...

  6. 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.

  7. 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 ...

  8. 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...

  9. 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...

  10. 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.

  11. 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.

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

    Science.gov (United States)

    Liu, Yaolin; Kong, Xuesong; Liu, Yanfang; Chen, Yiyun

    2013-01-01

    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.

  13. 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.

  14. 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...

  15. 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.

  16. 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

  17. Implementation of Associated Hermite FDTD Method in Handling INBCs for Shielding Analysis

    Directory of Open Access Journals (Sweden)

    Lihua Shi

    2016-01-01

    Full Text Available For modeling of electrically thin conductive shields, the unconditionally stable Associated Hermite (AH FDTD scheme is combined with the impedance network boundary conditions (INBCs in this paper. The two-port network equations of INBCs in frequency domain are transformed into AH domain to represent the relationship of tangential components of the electric and magnetic fields at faces of the shield. The established AH-INBCs shielding boundaries are incorporated into a set of implicit equations to calculate the expansion coefficients vectors of electromagnetic fields in the computational domain. The method is free of CFL condition and no convolution integral operation for solving the conventional INBCs-FDTD is involved. Numerical example shows that, compared with analytical solutions and conventional FDTD method, the proposed algorithm is efficient and accurate.

  18. 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.

  19. 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.

  20. Orientation Computing in Agent-Based Crowd Simulation%Agent-Based群体模拟中的朝向计算方法

    Institute of Scientific and Technical Information of China (English)

    叶青; 夏时洪; 毛天露; 蒋浩

    2011-01-01

    In agent-based crowd simulation, previous methods for computing orientation will lead to abrupt changes in agent's orientation, or generate stiffly turning behaviors. Therefore, the 3D performance of high-density crowd simulation deviates from reality. This paper presents a double-layer orientation fairing method for agent-based crowd animation. The theoretical layer computes an initial value of the individual orientation, considering the expected direction, the angular momentum constraints and the interfered rotation caused by surrounding obstacles. The numerical layer uses filtering technology for processing orientation data. The final orientation is interpolated between results from the two layers in hyperspherical space of quaternion. The method has proved to be effective to generate non-oscillatory and natural individual orientation, even for high-density crowd in complex environment.%基于智能体(agent-based)的群体模拟中,已有的朝向计算方法易产生个体的朝向突变或僵硬的转弯行为,导致高密度群体的三维运动效果失真.为此提出一种适用于agent-based模型的双层朝向处理方法.在理论层上,依据角动量约束构建出朝向旋转方程,在计算路径过程中综合考虑个体期望方向、角速度约束、外部干扰转动等因素,计算个体朝向的初值;在数据层上,采用朝向过滤技术对初值进行处理,并在四元素空间内进行球面插值,最终生成群体的运动朝向.实验结果证明,该方法能实时地计算出自然平滑的高密度群体朝向数据.

  1. 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

  2. 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...

  3. Stability analysis of FDTD to UPML for time dependent Maxwell equations

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We study an finite-difference time-domain (FDTD) system of uniaxial perfectly matched layer (UPML) method for electromagnetic scattering problems. Particularly we analyze the discrete initial-boundary value problems of the transverse magnetic mode (TM) to Maxwell’s equations with Yee’s algorithm. An exterior domain in two spacial dimension is truncated by a square with a perfectly matched layer filled by a certain artificial medium. Besides, an artificial boundary condition is imposed on the outer boundary of the UPML. Using energy method, we obtain the stability of this FDTD system on the truncated domain. Numerical experiments are designed to approve the theoretical analysis.

  4. 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.

  5. 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.

  6. Incorporating Social Oriented Agent and Interactive Simulation in E-learning: Impact on Learning, Perceptions, Experiences to Non-Native English Students

    Science.gov (United States)

    Ballera, Melvin; Elssaedi, Mosbah Mohamed

    2012-01-01

    There is an unrealized potential in the use of socially-oriented pedagogical agent and interactive simulation in e-learning system. In this paper, we investigate the impact of having a socially oriented tutor agent and the incorporation of interactive simulation in e-learning into student performances, perceptions and experiences for non-native…

  7. 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

  8. 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.

  9. 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)

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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 ...

  15. 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,...

  16. The effects of social interactions on fertility decline in nineteenth-century France: an agent-based simulation experiment.

    Science.gov (United States)

    González-Bailón, Sandra; Murphy, Tommy E

    2013-07-01

    We built an agent-based simulation, incorporating geographic and demographic data from nineteenth-century France, to study the role of social interactions in fertility decisions. The simulation made experimentation possible in a context where other empirical strategies were precluded by a lack of data. We evaluated how different decision rules, with and without interdependent decision-making, caused variations in population growth and fertility levels. The analyses show that incorporating social influence into the model allows empirically observed behaviour to be mimicked, especially at a national level. These findings shed light on individual-level mechanisms through which the French demographic transition may have developed.

  17. 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.

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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...

  4. 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

  5. 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.

  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. 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.

  8. 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

  9. 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.

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

    DEFF Research Database (Denmark)

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

    /CYSS) and mitochondrial redox couples. Evidence suggests that both intracellular and extracellular redox can affect overall cell redox state. How redox is communicated between extracellular and intracellular environments is still a matter of debate. Some researchers conclude based on experimental data...... will be the agents [7]. Additionally, the spatial distribution of enzymes and reactants, and diffusion of reactants will be considered as a contributing factor. To initially simplify the modeling, the redox change of intracellular compartments will be ignored or only the export and import of redox will be modeled...... for Autonomous Agents and Multiagent Systems: Toronto, Canada. p. 1633-1636....

  11. 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.

  12. Agent-Based Simulation of School Choice in Bandung, Indonesia: The Emergence of Enrolment Pattern Trough Individual Preferences

    Directory of Open Access Journals (Sweden)

    Dhanan Sarwo Utomo

    2012-01-01

    Full Text Available This study is motivated by the reality that school choice programs that is currently implemented in Bandung that, always resulting student deficit (lack of student in some schools. In this study, a mechanism that can describe how the enrollment pattern in a school choice program emerge as a result of individual preferences of the prospective students, is constructed. Using computer simulation, virtual experiments are conducted. In these experiments, the enrollment patterns and the number of student deficit that were resulted by various school choice program configurations are analyzed. Based on the experiment results, modification of the current program that can minimize the number of student deficit can be purposed.Keywords: agent-based simulation, school choice, computer simulation

  13. 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.

  14. 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.

  15. 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...... of the efficiency/effectiveness balance of the system, and a mechanism for competitor players' profiles definition....

  16. 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.

  17. Building agent-based simulations using structural and process mental models

    NARCIS (Netherlands)

    Stuit, Marco; Szirbik, Nick; Wortmann, Hans; Negru,; Jebelean, T; Petcu, D; Zaharie, D

    2007-01-01

    This paper provides a design rationale for a mechanism that enforces a correct mapping between a model of a nested agent organization and a model of a composite interaction-based business process. We use an example of a collaborative process to illustrate the features of this mechanism. The mapping

  18. 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

  19. 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.

  20. 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.

  1. User's manual for three dimensional FDTD version D code for scattering from frequency-dependent dielectric and magnetic materials

    Science.gov (United States)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The Penn State Finite Difference Time Domain Electromagnetic Scattering Code version D is a 3-D numerical electromagnetic scattering code based upon the finite difference time domain technique (FDTD). The manual provides a description of the code and corresponding results for several scattering problems. The manual is organized into 14 sections: introduction; description of the FDTD method; operation; resource requirements; version D code capabilities; a brief description of the default scattering geometry; a brief description of each subroutine; a description of the include file; a section briefly discussing Radar Cross Section computations; a section discussing some scattering results; a sample problem setup section; a new problem checklist; references and figure titles. The FDTD technique models transient electromagnetic scattering and interactions with objects of arbitrary shape and/or material composition. In the FDTD method, Maxwell's curl equations are discretized in time-space and all derivatives (temporal and spatial) are approximated by central differences.

  2. 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

  3. 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.

  4. ON AGENT-BASED REAL ESTATE PRICING SIMULATION%基于Agent的房价仿真研究

    Institute of Scientific and Technical Information of China (English)

    刘聪

    2012-01-01

    Analysis and prediction of real estate pricing is the focus and difficulty at present. The Agent-based modelling and simulation technology is able to construct a quite intact model for real estate pricing model. The real estate market and land market, as well as various related Agents such as the land provider, the developer, the buyer, the seller, and the investor, etc. are included in the model. By depicting the actions, decision making and interactions of these Agents, one can observe the results and phenomena emerged macroscopically from various environmental policies. In the model simulation, the impacts of the factors such as land supply, investment behaviour, interest rate, inflation rate, etc. on a variety of real estate pricing are studied and analysed. The simulation result well reflects and explains the status quo of the real estate pricing.%房价分析和预测是当前的热点和难点.基于Agent建模仿真技术,构建了较为完整的房价模型.模型包括房产市场和土地市场,以及房价相关各种主体,如土地供应者、开发商、买房者、投资者.通过刻画这些主体的行为、决策及交互,观察在不同的环境政策下,宏观涌现出来的结果和现象.模型仿真中研究和分析了土地供应、投资行为、利率、通胀等因素对房价走势的影响.仿真结果能较好地反映和解释房价的现实状况.

  5. 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 diseases are characterized by the misfolding and deposition of proteins in the body in the form of insoluble amyloid fibrils. Alzheimer’s disease and type 2 diabetes mellitus are two examples of amyloid diseases which are closely related both with respect to the atomic structures of the a......Amyloid diseases are characterized by the misfolding and deposition of proteins in the body in the form of insoluble amyloid fibrils. Alzheimer’s disease and type 2 diabetes mellitus are two examples of amyloid diseases which are closely related both with respect to the atomic structures...... of the 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...

  6. 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...

  7. Analysis of Interactions of Key Stakeholders on B2C e-Markets - Agent Based Modelling and Simulation Approach

    Directory of Open Access Journals (Sweden)

    Marković Aleksandar

    2016-05-01

    Full Text Available Background/purpose: This paper discusses the application of ABMS - agent-based modelling and simulation in the analysis of customer behaviour on B2C e-commerce websites as well as in the analysis of various business decisions upon the effects of on-line sales. The continuous development and dynamics in the field of e-commerce requires application of advanced decision-making tools. These tools must be able to process, in a short time period, a large amount of data generated by the e-commerce systems and enable the use of acquired data for making quality business decisions.

  8. 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...

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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...

  14. A Locally Conformal FDTD Analysis of Coupling Properties of a Doublet Slot Antenna in a Rectangular Waveguide

    Institute of Scientific and Technical Information of China (English)

    LILong; ZHANGYu; LIANGChanghong

    2003-01-01

    A locally conformal FDTD analysis of cou-pling properties of a doublet slot antenna in a rectangular waveguide is given in this paper, based on the principles of equivalence and superposition of electromagnetic fields.Firstly, a modified locally conformal finite-difference time-domain (MLC-FDTD) is presented, which is used to ana-lyze the arbitrarily shaped slots in a finite wall thickness waveguide. MLC-FDTD not only removes the instability of the original locally conformal FDTD algorithm, but also improves the computational accuracy by partly modifying magnetic field updated equations and the virtual electric fields according to the complexity of the slot fringe fields.Secondly, based on the MLC-FDTD, the coupling proper-ties of a two-slot antenna in a rectangular waveguide are analyzed by using the principles of equivalence and super-position of electromagnetic fields. The equivalent two-port network S parameters of one slot including the mutual cou-pling effect are given, which gives a basis of analysis of complicated coupling properties of the slot antenna array using FDTD method.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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)

  20. 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.

  1. 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.

  2. 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

    Concentration of magnetic resonance imaging (MRI) contrast agents (CA) cannot be measured directly and is commonly determined indirectly using their relaxation effect. This requires knowledge of the relaxivity of the used CA. Quantitative perfusion studies involve measurement of CA concentration...... studies (3,4) as demonstrated in (5). It was previously found (6) that the perfusion measurements using dynamic susceptibility contrast inherently overestimate cerebral blood flow and volume. In view of the present result, this is attributed to the significant difference in the relaxivity of the CA...

  3. 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...

  4. 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...

  5. 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.

  6. β-Glucan as an encapsulating agent: Effect on probiotic survival in simulated gastrointestinal tract.

    Science.gov (United States)

    Shah, Asima; Gani, Adil; Ahmad, Mudasir; Ashwar, Bilal Ahmad; Masoodi, F A

    2016-01-01

    Three strains of probiotics Lactobacillus casei, Lactobacillus brevis, and Lactobacillus plantarum were encapsulated in β-glucan matrix using emulsion technique. Further the encapsulated cells were studied for their tolerance in simulated gastrointestinal conditions and its storage stability. The average encapsulation efficiency of β-glucan-probiotic beads was found to be 74.01%. The surface morphology of β-glucan containing bacteria was studied using SEM. The noteworthy absorptions in the FT-IR spectra between 1300-900 cm(-1) and 2918-2925 cm(-1) corresponds to the presence of bacteria into the glucan matrix. Also, the thermal stability of β-glucan was evaluated using Differential Scanning Calorimeter. The efficiency of β-glucan in protecting the surviability of probiotic cells under simulated gastrointestinal conditions was studied. Results revealed significant (pencapsulated cells were subjected to stresses like low pH, heat treatment, simulated intestinal conditions and storage.

  7. 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.

  8. 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

  9. 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

    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...

  10. Being an "Agent Provocateur": Utilising Online Spaces for Teacher Professional Development in Virtual Simulation Games

    Science.gov (United States)

    deNoyelles, Aimee; Raider-Roth, Miriam

    2016-01-01

    This article details the results of an action research study which investigated how teachers used online learning community spaces to develop and support their teaching and learning of the Jewish Court of All Time (JCAT), a web-mediated, character-playing, simulation game that engages participants with social, historical and cultural curricula.…

  11. Multi-agent based modeling and execution framework for complex simulation, control and measuring tasks

    NARCIS (Netherlands)

    Papp, Z.; Hoeve, H.J.

    2000-01-01

    The paper presents a modeling concept and a supporting runtime environment, which enables running simulation, control and measuring (data processing) tasks on distributed implementation platforms. Its main features: (1) it is scaleable in various application domains; (2) it has a model based system

  12. 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.

  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. 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...

  17. 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...

  18. 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 ...

  19. Simulation of ethanol extractive distillation with mixed glycols as separating agent

    OpenAIRE

    I. D. Gil; L. C. García; Rodríguez, G.

    2014-01-01

    Extractive distillation is an alternative for ethanol dehydration processes that has been shown to be more effective than azeotropic distillation and, in close proximity, to be very competitive against the process that uses adsorption with molecular sieves. Glycols have been shown to be the most effective solvents in extractive distillation, mainly ethylene glycol and glycerol. In this work, an extractive distillation column was simulated with the Aspen Plus software platform, using the RadFr...

  20. 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...

  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. 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.

  3. 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

    markets data available on-line; capability of dealing with different file formats and types, some of them inserted by the user, resulting from information obtained not on-line but based on the possible collaboration with market entities; definition and implementation of database gathering information from...... 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...

  4. 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.

  5. 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.

  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. 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.

  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. (author)

  9. 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)

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. STABILITY AND SUPER CONVERGENCE ANALYSIS OF ADI-FDTD FOR THE 2D MAXWELL EQUATIONS IN A LOSSY MEDIUM

    Institute of Scientific and Technical Information of China (English)

    Gao Liping

    2012-01-01

    Several new energy identities of the two dimensional(2D) Maxwell equations in a lossy medium in the case of the perfectly electric conducting boundary conditions are proposed and proved.These identities show a new kind of energy conservation in the Maxwell system and provide a new energy method to analyze the alternating direction implicit finite difference time domain method for the 2D Maxwell equations (2D-ADI-FDTD).It is proved that 2D-ADI-FDTD is approximately energy conserved,unconditionally stable and second order convergent in the discrete L2 and H1 norms,which implies that 2D-ADI-FDTD is super convergent.By this super convergence,it is simply proved that the error of the divergence of the solution of 2D-ADI-FDTD is second order accurate.It is also proved that the difference scheme of 2D-ADI-FDTD with respect to time t is second order convergent in the discrete H1 norm.Experimental results to confirm the theoretical analysis on stability,convergence and energy conservation are presented.

  15. 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

  16. 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.

  17. 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.

  18. User's manual for three dimensional FDTD version A code for scattering from frequency-independent dielectric materials

    Science.gov (United States)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The Penn State Finite Difference Time Domain (FDTD) Electromagnetic Scattering Code Version A is a three dimensional numerical electromagnetic scattering code based on the Finite Difference Time Domain technique. The supplied version of the code is one version of our current three dimensional FDTD code set. The manual provides a description of the code and the corresponding results for the default scattering problem. The manual is organized into 14 sections: introduction, description of the FDTD method, operation, resource requirements, Version A code capabilities, a brief description of the default scattering geometry, a brief description of each subroutine, a description of the include file (COMMONA.FOR), a section briefly discussing radar cross section (RCS) computations, a section discussing the scattering results, a sample problem setup section, a new problem checklist, references, and figure titles.

  19. User's manual for three dimensional FDTD version B code for scattering from frequency-dependent dielectric materials

    Science.gov (United States)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The Penn State Finite Difference Time Domain Electromagnetic Code Version B is a three dimensional numerical electromagnetic scattering code based upon the Finite Difference Time Domain Technique (FDTD). The supplied version of the code is one version of our current three dimensional FDTD code set. This manual provides a description of the code and corresponding results for several scattering problems. The manual is organized into 14 sections: introduction, description of the FDTD method, operation, resource requirements, Version B code capabilities, a brief description of the default scattering geometry, a brief description of each subroutine, a description of the include file, a discussion of radar cross section computations, a discussion of some scattering results, a sample problem setup section, a new problem checklist, references and figure titles.

  20. User's manual for three dimensional FDTD version C code for scattering from frequency-independent dielectric and magnetic materials

    Science.gov (United States)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The Penn State Finite Difference Time Domain Electromagnetic Scattering Code Version C is a three-dimensional numerical electromagnetic scattering code based on the Finite Difference Time Domain (FDTD) technique. The supplied version of the code is one version of our current three-dimensional FDTD code set. The manual given here provides a description of the code and corresponding results for several scattering problems. The manual is organized into 14 sections: introduction, description of the FDTD method, operation, resource requirements, Version C code capabilities, a brief description of the default scattering geometry, a brief description of each subroutine, a description of the include file (COMMONC.FOR), a section briefly discussing radar cross section computations, a section discussing some scattering results, a new problem checklist, references, and figure titles.

  1. 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)

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

    Directory of Open Access Journals (Sweden)

    Z. L. He

    2012-01-01

    Full Text Available 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 how to obtain the highest efficiency of parallel FDTD algorithm by optimizing MPI virtual topology. To show the validity of the presented method, several numerical results are given in the later part. Various comparisons are made and some useful conclusions are summarized.

  3. “Space, the Final Frontier”: How Good are Agent-Based Models at Simulating Individuals and Space in Cities?

    Directory of Open Access Journals (Sweden)

    Alison Heppenstall

    2016-01-01

    Full Text Available Cities are complex systems, comprising of many interacting parts. How we simulate and understand causality in urban systems is continually evolving. Over the last decade the agent-based modeling (ABM paradigm has provided a new lens for understanding the effects of interactions of individuals and how through such interactions macro structures emerge, both in the social and physical environment of cities. However, such a paradigm has been hindered due to computational power and a lack of large fine scale datasets. Within the last few years we have witnessed a massive increase in computational processing power and storage, combined with the onset of Big Data. Today geographers find themselves in a data rich era. We now have access to a variety of data sources (e.g., social media, mobile phone data, etc. that tells us how, and when, individuals are using urban spaces. These data raise several questions: can we effectively use them to understand and model cities as complex entities? How well have ABM approaches lent themselves to simulating the dynamics of urban processes? What has been, or will be, the influence of Big Data on increasing our ability to understand and simulate cities? What is the appropriate level of spatial analysis and time frame to model urban phenomena? Within this paper we discuss these questions using several examples of ABM applied to urban geography to begin a dialogue about the utility of ABM for urban modeling. The arguments that the paper raises are applicable across the wider research environment where researchers are considering using this approach.

  4. The Application of the FDTD Method to Millimeter-Wave Filter Circuits Including the Design and Analysis of a Compact Coplanar

    Science.gov (United States)

    Oswald, J. E.; Siegel, P. H.

    1994-01-01

    The finite difference time domain (FDTD) method is applied to the analysis of microwave, millimeter-wave and submillimeter-wave filter circuits. In each case, the validity of this method is confirmed by comparison with measured data. In addition, the FDTD calculations are used to design a new ultra-thin coplanar-strip filter for feeding a THz planar-antenna mixer.

  5. 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 ...

  6. 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.

  7. 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...

  8. FDTD Studies of Eigenfrequencies and Q-factors of the Earth-ionosphere Cavity

    Science.gov (United States)

    Yang, H.; Pasko, V.

    2004-12-01

    Resonance properties of the Earth-ionosphere cavity were predicted by W. O. Schumann in 1952 [Schumann, Z. Naturforsch., 7a, 149, 1952]. Since then observations of electromagnetic signals in the frequency range 1-500 Hz have become a powerful tool for variety of remote sensing applications [e.g., Williams, Science, 256, 1184, 1992; Cummer, IEEE Trans. Antennas Propagat., 48, 1420, 2000; Roldugin et al., JGR, 109, A01216, 2004], which in recent years included studies of thunderstorm related transient luminous events in the middle atmosphere and related lightning discharges [e.g., Sato and Fukunishi, GRL, 30, 1859, 2003; Su et al., Nature, 423, 974, 2003]. In this talk we will provide a comparison of a limited set of results from a simplified version of a 3-D FDTD model of the Earth-ionosphere cavity originally introduced in [Yang and Pasko, EOS Trans. AGU, 84, Fall Meet. Suppl., AE42A-0796, 2003] with a set of classical eigenfrequency (fn) and quality factor (Qn) solutions for laterally uniform spherically symmetric Earth-ionosphere cavity and with recent observations of Schumann resonances (SR) during solar proton events (SPEs) and X-ray bursts in order to demonstrate the potential and applicability of the FDTD technique for studies of realistic SR problems. The specific uniform cavities, which will be discussed in our talk, incorporate the following conductivity models: (1) a single-exponential profile with a perturbation [Sentman, JATP, 45, 55, 1983]; (2) a "knee" profile [e.g., Mushtak and Williams, JASTP, 64, 1989, 2002]; and (3) a two-exponential profile [Greifinger and Greifinger, Radio Sci., 13, 831, 1978; Sentman, JATP, 52, 35, 1990; JGR, 101, 9479, 1996; Mushtak and Williams, 2002]. The FDTD fn and Qn solutions for uniform cavity appear to be in excellent agreement (within several %) with well-known results documented in the literature [e.g., Sentman, 1983; Mushtak and Williams, 2002], including such particular details as a very flat frequency dependence

  9. 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.

  10. 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-...

  11. 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.

  12. 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

  13. Reactivation of nerve agent-inhibited human acetylcholinesterase by obidoxime, HI-6 and obidoxime+HI-6: Kinetic in vitro study with simulated nerve agent toxicokinetics and oxime pharmacokinetics.

    Science.gov (United States)

    Worek, Franz; Koller, Marianne; Thiermann, Horst; Wille, Timo

    2016-03-28

    Despite extensive research for decades no effective broad-spectrum oxime for the treatment of poisoning by a broad range of nerve agents is available. Previous in vitro and in vivo data indicate that the combination of in service oximes could be beneficial. To investigate the ability of obidoxime, HI-6 and the combination of both oximes to reactivate inhibited human AChE in the presence of sarin, cyclosarin or tabun we adopted a dynamic in vitro model with real-time and continuous determination of AChE activity to simulate inhalation nerve agent exposure and intramuscular oxime administration. The major findings of this kinetic study are that the extent and velocity of reactivation is dependent on the nerve agent and the oxime-specific reactivating potency. The oxime-induced reactivation of inhibited human AChE in the presence of nerve agents is markedly impaired and the combination of obidoxime and HI-6 had no additive effect but could broaden the spectrum. In conclusion, these data indicate that a combination of obidoxime and HI-6 would be beneficial for the treatment of poisoning by a broad spectrum of nerve agents and could present an interim solution until more effective and broad-spectrum reactivators are available.

  14. 基于自主体的经济危机模拟%Agent-Based Simulation on Economic Crisis

    Institute of Scientific and Technical Information of China (English)

    顾高翔; 王铮; 姚梓璇

    2011-01-01

    基于自主体模拟的建模工具,结合序列创新理论,将创新体系引入自主体模型之中,开发了基于自主体的宏观经济过程模拟系统,并使用该系统用于对经济危机进行模拟,通过比较不同的金融政策对经济危机发生的原因和解决经济危机的办法做了初步的探究.研究结果表明,政府采取过分宽松的金融政策尽管可以在一段时间内使市场一片繁荣,社会产出快速增长,但是也会造成严重的通货膨胀,是金融危机乃至经济危机的产生的重要的原因.而在经济危机发生之后,开始可以采取适当的货币宽松政策,恢复就业、创新,提高生产技术,接着要稳定货币,防止震荡性通货膨胀.%In this paper, we developed an agent-based simulation system of macroeconomical process which based on ABS modeling tools and led sequential innovation theory into this model. Then it was used to simulate economic crisis and do a preliminary research into the reasons of economic crisis. Besides we tried to dig out the way of eliminating crisis by comparing different monetary policies in simulation. The results show that there will be a thriving market and a rapid growth of social output in case of an excessively loose monetary policy been adopted by government. However, loose policy will bring serious inflation which is a critical reason of the generation of financial crisis or even economic crisis. When economic crisis begins, the government should take an appropriate monetary policy to refresh the employment and innovation, and improve the technology. And next step would be stabilizing currency which aims at preventing the market from shocking inflation.

  15. [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

  16. 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

  17. 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.

  18. 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...

  19. 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)

  20. 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.

  1. 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.

  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. 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

  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. 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.

  8. 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...

  9. 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.

  10. User's manual for two dimensional FDTD version TEA and TMA codes for scattering from frequency-independent dielectric materials

    Science.gov (United States)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    The Penn State Finite Difference Time Domain Electromagnetic Scattering Code Versions TEA and TMA are two dimensional electromagnetic scattering codes based on the Finite Difference Time Domain Technique (FDTD) first proposed by Yee in 1966. The supplied version of the codes are two versions of our current FDTD code set. This manual provides a description of the codes and corresponding results for the default scattering problem. The manual is organized into eleven sections: introduction, Version TEA and TMA code capabilities, a brief description of the default scattering geometry, a brief description of each subroutine, a description of the include files (TEACOM.FOR TMACOM.FOR), a section briefly discussing scattering width computations, a section discussing the scattering results, a sample problem setup section, a new problem checklist, references, and figure titles.

  11. FDTD analysis of ELF radio waves propagating in the Earth-ionosphere waveguide

    Science.gov (United States)

    Marchenko, Volodymyr; Kulak, Andrzej; Mlynarczyk, Janusz

    2015-04-01

    We developed an FDTD model of electromagnetic wave propagation in the Earth-ionosphere cavity. We present the results of FDTD calculations assuming axisymmetric system with the source located at the north pole and with no dependence on azimuthal coordinate. Therefore we reduced the Maxwell equations to 2D spherical system of Maxwell equations. To model the conductivity profile of the Earth-ionosphere waveguide we used two models, namely one- and two-exponential profiles [Mushtak and Williams, 2002]. The day-night asymmetry was introduced by setting different model parameters for the north and south hemispheres. The ground was modeled as a perfect electric conductor. Also the upper boundary for the model was a perfect conductor but it was placed at a high enough altitude to make sure there is no reflection of the waves from this boundary. We obtained the results for the electric and magnetic field components of the propagating wave in the time and frequency domains and for various locations on Earth along the meridian. In the time domain we analyzed the evolution of the electric and magnetic field components of the radio wave generated by lighting for different probe position, the penetration of the ionosphere by the electromagnetic waves and the reflection of the waves on the terminator. In the frequency domain we analyzed the Schumann resonance spectra in different field components for different location in the computational space, the behavior of the Poynting vector and the wave impedance. We also calculated real and imaginary parts of the characteristic electric and magnetic altitudes for the daytime and nighttime ionosphere. The analysis in the frequency domain was performed up to 1 kHz. We compared the results of numerical calculations with our analytical model and found a reasonably good agreement between them. The results can be used in the analysis of global thunderstorm activity based on measurements of Schumann resonance spectra. Acknowledgements. This

  12. Nano-Optical Device Design with the Use of Open-Source Parallel Version FDTD and Commercial Finite Element Package

    CERN Document Server

    Liu, Y

    2013-01-01

    In this paper, the implementation of open-source parallel-version FDTD (Finite-Difference-Time-Domain) software, MEEP, on Texas A&M supercomputers and commercial finite element package, COMSOL, on a single workstation for the design design of nano-optical device is reported. The the computer architecture and performance of both numerical methods on the same design will be briefly described.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Land Use for Marsh Beach. 4-H Marine Science Simulation Game. Member's Guide [and] Agent's Supplement. MSp 5 [and] 6.

    Science.gov (United States)

    Auburn Univ., AL. Cooperative Extension Service.

    A six-part marine science simulation game for 4-H members concerning land use in a hypothetical community is provided. The major problem is to decide what are some possible uses of a three-mile (1,250 acre) Marsh Beach which the city recently purchased. Members assume the roles of decision-makers in the simulated environment and compete for…

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. The Power Trading Agent Competition

    NARCIS (Netherlands)

    W. Ketter (Wolfgang); J. Collins (John); P. Reddy (Prashant); C. Flath (Christoph)

    2011-01-01

    textabstractThis 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Simulation Method of Agents' Tears Flowing%虚拟人眼泪流淌现象的动画仿真方法

    Institute of Scientific and Technical Information of China (English)

    肖苗苗; 刘箴; 史佳宾; 金炜; 刘婷婷; 刘翠娟; 刘邦权

    2015-01-01

    为了增强虚拟人表情动画的真实感, 通过在表情动画中加入基于流体物理的虚拟人眼泪仿真, 提出一种虚拟人流泪仿真方法. 在预处理时, 将三维中的流淌仿真映射到二维空间, 以避免三维空间中点-面碰撞检测开销较大的问题; 仿真时, 着重考虑皮肤和眼泪之间的作用力、黏附力以及表面张力; 渲染时, 根据二维上的位置信息生成法线纹理, 再采用改进的法线贴图的方法渲染出虚拟人流泪的效果. 实验结果表明, 该方法能够实时地模拟虚拟人的流泪效果.%Tears simulation based on fluid physics is added into the facial animation of the agents to increase realism. A method is presented to simulate tears. In pre-processing, the flowing in 3D is mapped to the 2D space, which could avoid the problem of point-surface collision detection in 3D. In simulation, the emphasis is put on the analysis of the force between skin and tears, adhesive force and surface tension. In rendering, the normal texture is generated according to the 2D position of the particles, crying scenario is rendered, using improved normal texture mapping technique. The method is confirmed by the demo of the agent crying in real-time.

  12. 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.

  13. Molecular dynamics simulations of sonic hedgehog-receptor and inhibitor complexes and their applications for potential anticancer agent discovery.

    Directory of Open Access Journals (Sweden)

    Swan Hwang

    Full Text Available The sonic hedgehog (Shh signaling pathway is necessary for a variety of development and differentiation during embryogenesis as well as maintenance and renascence of diverse adult tissues. However, an abnormal activation of the signaling pathway is related to various cancers. In this pathway, the Shh signaling transduction is facilitated by binding of Shh to its receptor protein, Ptch. In this study, we modeled the 3D structure of functionally important key loop peptides of Ptch based on homologous proteins. Using this loop model, the molecular interactions between the structural components present in the pseudo-active site of Shh and key residues of Ptch was investigated in atomic level through molecular dynamics (MD simulations. For the purpose of developing inhibitor candidates of the Shh signaling pathway, the Shh pseudo-active site of this interface region was selected as a target to block the direct binding between Shh and Ptch. Two different structure-based pharmacophore models were generated considering the key loop of Ptch and known inhibitor-induced conformational changes of the Shh through MD simulations. Finally two hit compounds were retrieved through a series of virtual screening combined with molecular docking simulations and we propose two hit compounds as potential inhibitory lead candidates to block the Shh signaling pathway based on their strong interactions to receptor or inhibitor induced conformations of the Shh.

  14. 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.

  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. Novel Role of Rural Official Organization in the Biomass-Based Power Supply Chain in China: A Combined Game Theory and Agent-Based Simulation Approach

    Directory of Open Access Journals (Sweden)

    Kaiyan Luo

    2016-08-01

    Full Text Available Developing biomass-based power generation is helpful for China to reduce the dependence on fossil fuels and to release the targets of carbon emission peak. The decentralized farming method leads to Chinese farmers’ weak willingness to collect and sell crop residues to biomass-based power plants. The purpose of this paper is to solve the issue by proposing a novel biomass feedstock supply model with China’s rural official organization—villagers’ committee, which has great influence on villagers’ decision making. Introducing it into the biomass-based power supply chain is beneficial to motivating farmers’ supplying enthusiasm. A combined game theory and agent-based simulation approach is applied to study the effectiveness of this new supply model. Multiple simulation scenarios are built to study impacts of different simulation parameters, and results show that farmers tend to supply more biomass material for electricity production in the proposed villagers’ committee model, compared with the two conventional supply models, direct-deal and broker models. The supply model incorporating the rural official organization can ensure the feedstock sufficiency for plants. A proper model design depends on the feed-in tariff subsidy for biomass-based electricity, feedstock shipping distance, performance appraisal system of the villagers’ committee, as well as farmers’ utility weights on net income and public service improvement.

  17. 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.

  18. 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

  19. In Vitro Dissolution of Fluconazole and Dipyridamole in Gastrointestinal Simulator (GIS), Predicting in Vivo Dissolution and Drug-Drug Interaction Caused by Acid-Reducing Agents.

    Science.gov (United States)

    Matsui, Kazuki; Tsume, Yasuhiro; Amidon, Gregory E; Amidon, Gordon L

    2015-07-01

    Weakly basic drugs typically exhibit pH-dependent solubility in the physiological pH range, displaying supersaturation or precipitation along the gastrointestinal tract. Additionally, their oral bioavailabilities may be affected by coadministration of acid-reducing agents that elevate gastric pH. The purpose of this study was to assess the feasibility of a multicompartmental in vitro dissolution apparatus, Gastrointestinal Simulator (GIS), in predicting in vivo dissolution of certain oral medications. In vitro dissolution studies of fluconazole, a BCS class I, and dipyridamole, a BCS class II weak bases (class IIb), were performed in the GIS as well as United States Pharmacopeia (USP) apparatus II and compared with the results of clinical drug-drug interaction (DDI) studies. In both USP apparatus II and GIS, fluconazole completely dissolved within 60 min regardless of pH, reflecting no DDI between fluconazole and acid-reducing agents in a clinical study. On the other hand, seven-fold and 15-fold higher concentrations of dipyridamole than saturation solubility were observed in the intestinal compartments in GIS with gastric pH 2.0. Precipitation of dipyridamole was also observed in the GIS, and the percentage of dipyridamole in solution was 45.2 ± 7.0%. In GIS with gastric pH 6.0, mimicking the coadministration of acid-reducing agents, the concentration of dipyridamole was equal to its saturation solubility, and the percentage of drug in solution was 9.3 ± 2.7%. These results are consistent with the clinical DDI study of dipyridamole with famotidine, which significantly reduced the Cmax and area under the curve. An In situ mouse infusion study combined with GIS revealed that high concentration of dipyridamole in the GIS enhanced oral drug absorption, which confirmed the supersaturation of dipyridamole. In conclusion, GIS was shown to be a useful apparatus to predict in vivo dissolution for BCS class IIb drugs.

  20. Compatibility and stability of palonosetron hydrochloride with four neruomuscular blocking agents during simulated y-site administration.

    Science.gov (United States)

    Trusley, Craig; Ben, Michael; Kupiec, Thomas C; Trissel, Lawrence A

    2008-01-01

    Palonosetron hydrochloride is a longer-acting selective 5-HT3 receptor antagonist that has been approved for the prevention of chemotherapy-induced nausea and vomiting and is being evaluated for the prevention of postoperative nausea and vomiting. The objective of this study was to evaluate the physical and chemical stability of palonosetron hydrochloride 50 mcg/mL when mixed with any of the neuromuscular blocking drugs cisatracurium besylate 0.5 mg/mL, rocuronium bromide 1 mg/mL, succinylcholine chloride 2 mg/mL, and vecuronium bromide 1 mg/mL during simulated Y-site administration. Triplicate samples of palonosetron hydrochloride with each of the neuromuscular blocking drugs were tested. Samples were stored and evaluated for up to 4 hours at room temperature. Physical stability was assessed by turbidimetric and particulate measurements and visual inspection. Chemical stability was assessed by high-performnace liquid chromatography. All of the admixtures were clear and colorless when viewed in normal fluorescent room light and when viewed with a Tyndall beam. Measured turbidity and particulate content were low initially and remained low throughout the study. The drug concentration was unchanged in all of the samples tested. Palonosetron hydrochloride is physically and chemically stable with cisatracurium besylate, rocuronium bromide, succinylcholine chloride, or vecuronium bromide at the concentrations tested during simulated Y-site administration over 4 hours at ambient room temperature. PMID:23969608

  1. La Ville comme Système Complexe. Physique Statistique et Simulations Multi-Agents sur des Modèles Urbains

    OpenAIRE

    Lemoy, Rémi

    2011-01-01

    Les sciences "dures" et les sciences humaines ont un intérêt commun pour les phénomènes collectifs, qui sont également un sujet de recherche important dans le domaine des systèmes complexes. Cette thèse se focalise sur l'étude des systèmes urbains, en utilisant des outils analytiques venant de la physique statistique, et des simulations, en particulier la modélisation multi-agents. Une première résolution analytique d'un modèle de ségrégation spatiale de Schelling est obtenue à l'aide d'un fo...

  2. Modélisation et simulation à base d'agents exemples commentés, outils informatiques et questions théoriques

    CERN Document Server

    Treuil, Jean-Pierre; Zucker, Jean-Daniel

    2008-01-01

    Cet ouvrage s'adresse aux étudiants de master des universités et aux élèves des écoles d'ingénieurs ainsi qu'aux mathématiciens, informaticiens et chercheurs de diverses disciplines qui sont amenés à créer des modèles dans leur domaine. La modélisation informatique à base d'agents permet de modéliser, à l'échelle macroscopique, des systèmes complexes à partir du comportement à l'échelle microscopique d'un grand nombre de leurs composants. L'objectif de ce livre se décline en cinq points complémentaires : Présenter au lecteur un panorama des approches de modélisation et simulation à base d'agents sous la forme de 11 exemples représentatifs puisés dans différents domaines scientifiques et technologiques. Proposer un cadre commun de définitions et une ébauche de démarche de conception qui permettent de fournir, au-delà de leur diversité apparente, une base sinon théorique du moins pratique de ces approches. Présenter les outils informatiques existants pour concevoir, spécifier...

  3. Ideal free distribution or dynamic game? An agent-based simulation study of trawling strategies with varying information

    Science.gov (United States)

    Beecham, J. A.; Engelhard, G. H.

    2007-10-01

    An ecological economic model of trawling is presented to demonstrate the effect of trawling location choice strategy on net input (rate of economic gain of fish caught per time spent less costs). Fishing location choice is considered to be a dynamic process whereby trawlers chose from among a repertoire of plastic strategies that they modify if their gains fall below a fixed proportion of the mean gains of the fleet as a whole. The distribution of fishing across different areas of a fishery follows an approximate ideal free distribution (IFD) with varying noise due to uncertainty. The least-productive areas are not utilised because initial net input never reaches the mean yield of better areas subject to competitive exploitation. In cases, where there is a weak temporal autocorrelation between fish stocks in a specific location, a plastic strategy of local translocation between trawls mixed with longer-range translocation increases realised input. The trawler can change its translocation strategy in the light of information about recent trawling success compared to its long-term average but, in contrast to predictions of the Marginal Value Theorem (MVT) model, does not know for certain what it will find by moving, so may need to sample new patches. The combination of the two types of translocation mirrored beam-trawling strategies used by the Dutch fleet and the resultant distribution of trawling effort is confirmed by analysis of historical effort distribution of British otter trawling fleets in the North Sea. Fisheries exploitation represents an area where dynamic agent-based adaptive models may be a better representation of the economic dynamics of a fleet than classically inspired optimisation models.

  4. Simulations

    CERN Document Server

    Ngada, N M

    2015-01-01

    The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simulations. Some practical applications of each simulation type are also considered. The final conclusion then summarizes the main important items to keep in mind before opting for a simulation tool or before performing a simulation.

  5. Multi-Agent Modeling and Simulation of Farmland Use Change in a Farming–Pastoral Zone: A Case Study of Qianjingou Town in Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Xuehong Bai

    2015-11-01

    Full Text Available Farmland is the most basic material condition for guaranteeing rural livelihoods and national food security, and exploring management strategies that take both stable rural livelihoods and sustainable farmland use into account has vital significance in theory and practice. Farmland is a complex and self-adaptive system that couples human and natural systems, and natural and social factors that are related to its changing process need to be considered when modeling farmland changing processes. This paper uses Qianjingou Town in the Inner Mongolian farming–pastoral zone as a study area. From the perspective of the relationship between household livelihood and farmland use, this study establishes the process mechanism of farmland use change based on questionnaire data, and constructs a multi-agent simulation model of farmland use change using the Eclipse and Repast toolbox. Through simulating the relationship between natural factors (including geographical location and household behavior, this paper systematically simulates household farmland abandonment and rent behaviors, and accurately describes the dynamic interactions between household livelihoods and the factors related to farmland use change. These factors include natural factors (net primary productivity, road accessibility, slope and relief amplitude and social factors (household family structures, economic development and government policies. Ultimately, this study scientifically predicts the future farmland use change trend in the next 30 years. The simulation results show that the number of abandoned and sublet farmland plots has a gradually increasing trend, and the number of non-farming households and pure-outworking households has a remarkable increasing trend, whereas the number of part-farming households and pure-farming households has a decreasing trend. Household livelihood sustainability in the study area is confronted with increasing pressure, and household non

  6. Multi-agent modeling and simulation of farmland use change in the farming-pastoral zone: A case study of Qianjingou Town in Inner Mongolia, China

    Science.gov (United States)

    Yan, H.

    2015-12-01

    Farmland is the most basic material conditions for guaranteeing rural livelihoods and national food security, and exploring management strategies that take both of the sustainable rural livelihoods and sustainable farmland use into account has vital significance of theory and practice. Farmland is a complex and self-adaptive system that couples human and natural systems together, and natural factors and social factors that are related to its changing process need to be considered when modeling farmland changing process. This paper takes Qianjingou Town in Inner Mongolia farming-pastoral zone as study area. From the perspective of the relationship between households' livelihoods and farmland use, this study builds the process mechanism of farmland use change based on questionnaires data, and constructs multi-agent simulation model of farmland use change with the help of Eclipse and Repast toolbox. Through simulating the relationship between natural factors (with geographical location) and households' behaviors, this paper systematically simulates households' renting and abandoning farmland behaviors, and truly describes dynamic interactions between households' livelihoods and factors related to farmland use change. These factors include natural factors (net primary productivity, road accessibility, slope and relief amplitude) and social factors (households' family structures, economic development and government policies). In the end, this study scientifically predicts farmland use change trend in the future 30 years. The simulation results show that, the number of abandoned and sublet farmland plots has a gradually increasing trend, the number of non-farm households and pure-outwork households has a remarkable increasing trend, and the number of part-farm households and pure-farm households shows a decreasing trend. Households' livelihoods sustainability in the study area is confronted with increasing pressure, and households' nonfarm employment has an increasing

  7. SIMULATING CONSUMER BEHAVIOUR PATTERN WITH MULTI-AGENT MODEL%基于多主体的消费者行为模式仿真

    Institute of Scientific and Technical Information of China (English)

    陈力

    2011-01-01

    为了更好地探究消费者保守行为模式,发掘市场中隐含的内在机制,使用了基于多主体的模型来模拟虚拟市场中的消费者行为.通过创建大量受到动机函数驱使,并且能够交互的主体,从而来模拟市场中人们的购买决策行为,了解人们的购买决策受到哪些因素的影响.同时在主体模型的基础上,构建了抽象社会关系网络.随着市场的发展,与之对应的底层网络结构也会随之演化.由此涌现出的一些宏观群体特性,也从不同的角度合理解释了"诱饵效应"和"锁定效应"这样的消费者行为模式.证实了不同阶层的消费者消费行为模式会有所不同.%In order to better explore the conservative behaviour of the consumers, discover inherent and internal mechanism in the market,in this paper we use multi-agent model to simulate the behaviour of consumers in virtual market. By creating a lot of interactive Agents with different characteristics and the same motivation function, the model simulates the purchasing decision behaviour in market and reveals the influence factors of their purchasing decision. Based on this model, we construct an abstract social relationship network on the basis of Agent model. The structure of the corresponding network at first floor will evolve along with the development of the market. The characteristic of macro population emerged from the network gives reasonable explanation from different prospect to such consumers' behaviour patterns of decoy effect and lock-in effect. And the results prove that the behaviour pattern varies from consumer to consumer of different ranks.

  8. Multi-agent Based Simulation of Retail Spatial Structure%基于多代理人的零售业空间结构模拟

    Institute of Scientific and Technical Information of China (English)

    朱玮; 王德

    2011-01-01

    中心地理论的提出由来已久,但对现实中多种因素复杂作用下的中心地体系进行实证研究并指导规划实践一直难以开展.传统模拟研究方法采用数学线性规划的思路,通过优化目标函数来实现对中心地体系的还原与考察,但复杂程度有限,难以用于实证研究和实践.多代理人技术的出现提供了新的研究思路.本文介绍笔者开发的一个零售业空间结构模拟系统.该系统以多代理人技术为基础,通过模拟商业中心和消费者两类代理人的行为,得出商业中心结构分布.商业中心被分为3个等级,可以根据经营收入调整空间位置和自身服务等级;消费者以一定的频率产生不同等级的购物需求,并以距离为指标选择商业中心作为出行目的地.模拟过程从产生一定数量的一级商业中心开始,经过循环模拟消费者选择行为和商业中心的位置等级调整,最终达到商业中心等级和空间分布的平衡状态.作为对这个模拟系统的检验,分别对5种典型的消费者空间分布场景进行模拟,包括:均匀分布、单中心、卫星城、分散组团、带形组团.结果表明这个系统的模拟性能稳定,生成的商业中心结构合理.%Although central place theory has been proposed for a long time, empirical research and planning practices on central place systems in the real world under the complex multi-factor interactions are difficult to carry out. Conventional simulation-based research methods use linear programming technique to derive and investigate central place systems through optimizing certain objective functions. But their limitations on model complexity restrict their further application in empirical research and practice. Multi-agent technology provides a new perspective. This paper proposes a multi-agent retail spatial structure simulation system, which can derive structural distributions of shopping centers through simulating the behavior of

  9. The electrochemical impedance spectroscopy of silver doped hydroxyapatite coating in simulated body fluid used as corrosive agent

    Directory of Open Access Journals (Sweden)

    Mišković-Stanković Vesna

    2012-01-01

    Full Text Available Titanium is a key biomedical material due its good biocompatibility, mechanical properties and corrosion stability, but infections of the implantation site still pose serious threat. One approach to prevent infection is to improve antimicrobial ability of the coating material. Silver doped hydroxyapatite (Ag/HAP nanoparticles were synthesized by new modified precipitation method. The synthesized powder was used for preparation of Ag/HAP coating on titanium by electrophoretic deposition. The coating was characterized in terms of phase composition and structure by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR and X-ray diffraction (XRD; surface morphology and chemical composition was assessed using scanning electron microscopy (SEM and energy dispersive spectroscopy (EDS. Research focused on evaluation of the corrosion behaviour of Ag/HAP coating in simulated body fluid (SBF at 37 ºC during prolonged immersion time by electrochemical impedance spectroscopy (EIS. Silver doped HAP coating provided good corrosion protection in SBF solution. [Acknowledgements. This research was financed by the Ministry of Education, Science and Technological Development of the Republic of Serbia, contracts No. III 45019 and by National Sciences and Engineering Research Council of Canada (NSERC. Dr Ana Jankovic was financed by the FP7 Nanotech FTM Grant Agreement 245916

  10. Use of an agent-based simulation model to evaluate a mobile-based system for supporting emergency evacuation decision making.

    Science.gov (United States)

    Tian, Yu; Zhou, Tian-Shu; Yao, Qin; Zhang, Mao; Li, Jing-Song

    2014-12-01

    Recently, mass casualty incidents (MCIs) have been occurring frequently and have gained international attention. There is an urgent need for scientifically proven and effective emergency responses to MCIs, particularly as the severity of incidents is continuously increasing. The emergency response to MCIs is a multi-dimensional and multi-participant dynamic process that changes in real-time. The evacuation decisions that assign casualties to different hospitals in a region are very important and impact both the results of emergency treatment and the efficiency of medical resource utilization. Previously, decisions related to casualty evacuation were made by an incident commander with emergency experience and in accordance with macro emergency guidelines. There are few decision-supporting tools available to reduce the difficulty and psychological pressure associated with the evacuation decisions an incident commander must make. In this study, we have designed a mobile-based system to collect medical and temporal data produced during an emergency response to an MCI. Using this information, our system's decision-making model can provide personal evacuation suggestions that improve the overall outcome of an emergency response. The effectiveness of our system in reducing overall mortality has been validated by an agent-based simulation model established to simulate an emergency response to an MCI. PMID:25354665

  11. 基于Agent的居民就医选择建模与仿真%Agent-based Modeling and Simulation Research into Residents Healthcare Choice

    Institute of Scientific and Technical Information of China (English)

    程贲; 李兴兵; 鲁延京; 谭跃进

    2009-01-01

    基于Agent建模仿真是医疗服务领域中问题研究和政策分析的一种新方法.在分析目前医疗领域中居民就医选择现状的基础上,基于Agent的建模方法,对医疗系统中的主要对象--医院、社区医疗服务机构、居民的行为进行了建模,开发了基于Anylogic的居民就医选择的仿真原型,研究了居民的就医选择问题,分析扩大不同医疗机构的费用差距及增加区域内社区医疗服务机构数量两项政策对居民就医选择的影响.实验结果说明通过调节医院与社区诊所的医疗服务的价格比,能够影响居民就医选择,但增加医院的医疗服务的价格会造成部分低收入居民无法就医;区域内社区诊所与医院的比例在2~4倍时,对降低居民无法就医的比例是有效的.%Agent-based modeling and simulation is a new methodology in the field of healthcare service research and relevant policy analysis. Applying agent-based modeling and simulation methodology, we research the problem of residents' healthcare selection and construct health service models for hospitals, residents and communities. Applying the simulation tool -AnyLogic, we analyze the effects of two policies on residents' health care choice, which involve enlarging the price gap of different healthcare institutions and increasing the number of healthcare service agencies in communities within a region. The experiment result illustrates that changing the cost ratio of hospital and community service has a significant impact on residents' selection decision, while the rising of the price of healthcare service makes residents with low income unable to afford the expense of healthcare service, and that the proper ratio of the number of community health service agencies to that of hospitals within a certain region is 2 to 4.

  12. Cultural Differentiation of Negotiating Agents

    NARCIS (Netherlands)

    Hofstede, G.J.; Jonker, C.M.; Verwaart, D.

    2012-01-01

    Negotiations proceed differently across cultures. For realistic modeling of agents in multicultural negotiations, the agents must display culturally differentiated behavior. This paper presents an agent-based simulation model that tackles these challenges, based on Hofstede’s model of national cultu

  13. Cultural differentiation of negotiating agents

    NARCIS (Netherlands)

    Hofstede, G.J.; Jonker, C.M.; Verwaart, T.

    2010-01-01

    Negotiations proceed differently across cultures. For realistic modeling of agents in multicultural negotiations, the agents must display culturally differentiated behavior. This paper presents an agent-based simulation model that tackles these challenges, based on Hofstede’s model of national cultu

  14. 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.

  15. 基于多主体的舆论建模与仿真研究%Modeling and simulation of public opinion based on multi-agent system

    Institute of Scientific and Technical Information of China (English)

    刘怡君

    2011-01-01

    "Public opinion comes before the unrest" has become a consensus. Understanding and capturing the essential mechanism of opinion formation and infection will provide help for forecasting and macroeconomic regulation. Public opinion is an open complex giant system, in which studying opinion based on modeling and simulation analysis is a more comprehensive and effective means. The paper presents one overall model of methodology-method-technology-simulation from the view of systems science besides going through the definitions of Wuli-Shili-Renli and multi-agent system, then summarizes the individuals' behaviors such as "conformity","power","egoism", etc., analyzes individual choices and constructs three interaction rules. The opinion evolution process was simulated quantitatively and some primary conclusions were obtained.%“舆论在先,动乱在后”,已成为普遍共识的认知.研究舆论的形成机理及其演化规律,进而调控舆论传播的导向有着重要的理论和现实意义.舆论系统是一个典型的复杂系统,系统建模与仿真分析是舆论全方位研究的有效手段.本文以物理-事理-人理系统方法论为指导,以多主体建模方法为手段,以舆论可视化仿真平台为依托,定义了舆论主体的偏好行为,模拟了舆论演化的过程,总结了舆论演化的规律.

  16. Numerical simulation of pressure waves in the cochlea induced by a microwave pulse.

    Science.gov (United States)

    Yitzhak, Nir M; Ruppin, Raphael; Hareuveny, Ronen

    2014-10-01

    The pressure waves developing at the cochlea by the irradiation of the body with a plane wave microwave pulse are obtained by numerical simulation, employing a two-step finite-difference time-domain (FDTD) algorithm. First, the specific absorption rate (SAR) distribution is obtained by solving the Maxwell equations on a FDTD grid. Second, the temperature rise due to this SAR distribution is used to formulate the thermoelastic equations of motion, which are discretized and solved by the FDTD method. The calculations are performed for anatomically based full body human models, as well as for a head model. The dependence of the pressure amplitude at the cochlea on the frequency, the direction of propagation, and the polarization of the incident electromagnetic radiation, as well as on the pulse width, was investigated.

  17. Evolutionary model of coal mine water hazards based on multi-agent simulation%基于multi—agent的煤矿水害演化模型

    Institute of Scientific and Technical Information of China (English)

    龚承柱; 李兰兰; 柯晓玲; 诸克军

    2012-01-01

    Based on coal mine hydrogeological conditions, the causes and evolution mechanism of coal mine water hazards were presented. By using complex systems theory and multi-agent modeling method, an evolutionary model of coal mine water hazards was developed. Then simulated the evolution process with different system conditions by Netlogo platform, and the coal mine water hazards process and vulnerability relationship were demonstration dynamical. The research shows that, the coal mine water hazards, influenced by multiple factors,is a complex and adaptive phenomenon that possesses nonlinear dynamic characteristics. Only by understanding the mine hydrogeological conditions, use complex systems theory and multi-agent modeling method, the mechanism of coal mine water hazards can be uncovered in nature.%根据矿区的水文地质条件,分析了煤矿水害事故的形成原因和演化机制,采用复杂系统理论和多主体建模方法,建立了煤矿水害演化模型;利用NetLogo仿真平台,对不同类型水害事故进行仿真模拟,动态表现煤矿水害演化过程以及影响因素之间的脆弱性关系。研究表明:煤矿水害是一种受控于多种因素、具有非线性动力特征的复杂自适应现象,只有了解矿区水文地质条件,并将复杂系统理论和多主体建模方法引入水害防治研究中.才能从本质上描述水害演化机制。

  18. Agent-based simulations of the influence of social policy and neighboring communication on the adoption of grid-connected photovoltaics

    International Nuclear Information System (INIS)

    Highlights: • Multi-agent systems coupled with an electric power flow analysis. • Influence of social policy and communication on the adoption of photovoltaics. • Strong intervention near a transformer drives the greatest PV adoption. • Strong intervention far from a transformer increases social costs. - Abstract: Agent-based simulations coupled with an analysis of the flow of electric power are carried out to examine the influence of the social policy of the government and the neighboring communication between customers on the adoption of distributed rooftop photovoltaic electrical power generators (PVs). How the relationships between the social policy and the possibility of a reverse current restriction give rise to the collective behavior of autonomous individuals, and how the end customers interact and form relationships with its environment are described. Strong intervention by the government in the areas near a main high-voltage power distribution transformer, where the possibility of a reverse current restriction is relatively low, drives the greatest adoption of the PV system. The near areas are primarily occupied by customers with only a PV to improve the diffusion rate of PVs via the self-organization by the communication between customers. It also lead in a decrease in the need for compensation devices, which in turn minimizes the social cost. Growth in the number of PVs in areas far from the transformer is assisted by the installation of batteries as compensation for the lost opportunity due to restrictions in those areas on reverse power currents. Therefore, excessive intervention by the government in the far areas results in an increase in the social cost of managing reverse currents

  19. 基于多主体的UGC监管仿真研究1$%Multi-agent Simulation on UGC Regulation

    Institute of Scientific and Technical Information of China (English)

    田丽; 李小宇

    2015-01-01

    本文在区别网络 UGC相关主体行为特征和主要关系的基础上,通过多主体建模和计算实验,模拟了互联网 UGC及其监管过程,对不同的监管策略的效果做了仿真研究。本文发现影响 UGC生态的根本因素是用户群体的心理偏好与生产能力;网站自我监管可以平衡收益与监管需求;政府的清理整顿行动对全局信息质量的持续提高作用不大,但会显著降低 UGC的规模和积极性;带有政策反馈的监管模式是令参与各方都满意的理想机制,需要完善相关的信息沟通和政策评价渠道。%By distinguishing the behavior patterns of and the relationships among the agents,this paper simulates the UGC process as well as the effectiveness of different regulation strategies. This study has found that users’ mental preference and the capability of information producing is the fundamental factor influencing UGC; the self-discipline of websites can balance the income and regulation tasks ;the regulation campaign launched by the government doesn’t help much to improve the global information quality but can harm the scale and positivity of UGC; the regulation with policy feedback can moderate the pursuits of different agents,which calls for improving the information sharing and policy evaluation conduits.

  20. FDTD Analysis of Reflection of Electromagnetic Wave From a Conductive Plane Covered with Inhomogeneous Time-Varying Plasma

    Institute of Scientific and Technical Information of China (English)

    刘少斌; 莫锦军; 袁乃昌

    2003-01-01

    A finite-difference time-domain (FDTD) algorithm is applied to study the electro-magnetic reflection of conduction plane covered with inhomogeneous time-varying plasma, homo-geneous plasma and inhomogeneous plasma. The collision frequency of plasma is a function ofelectron density and plasma temperature. The number density profile follows a parabolic func-tion. A discussion on the effect of various plasma parameters on the reflection coefficient is pre-sented. Under the one-dimensional case, transient electromagnetic propagation through variousplasmas has been obtained, and the reflection coefficients of EM wave through various plasmasare calculated under different conditions. The results illustrate that a plasma cloaking system cansuccessfully absorb the incident EM wave.