Journal of Advanced Simulation in Science and Engineering
Online ISSN : 2188-5303
ISSN-L : 2188-5303
Volume 6, Issue 2
Displaying 1-7 of 7 articles from this issue
Regular Section
Papers
  • Yoshiki Mizuno, Naoto Mitsume, Tomonori Yamada, Shinobu Yoshimura
    2019 Volume 6 Issue 2 Pages 282-297
    Published: 2019
    Released on J-STAGE: August 31, 2019
    JOURNAL FREE ACCESS

    This paper presents a time-based dynamic load balancing algorithm for efficient domain decomposition by the Explicit Moving Particle Simulation (EMPS) method with the Explicitly Represented Polygon (ERP) wall boundary model in three-dimensional computational domains. This proposed algorithm utilizes calculation time required for the EMPS and ERP algorithms to decompose analysis domains. Compared to a distributed memory parallel algorithm that partitions computational domains based on the number of particles, the newly designed algorithm simulates free-surface flow problems with less computational cost. This paper also demonstrates the parallel efficiency of the time-based dynamic load balancing algorithm by dynamic load balancing and strong scaling efficiency tests.

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  • Kenichi Ito
    2019 Volume 6 Issue 2 Pages 298-316
    Published: 2019
    Released on J-STAGE: August 31, 2019
    JOURNAL FREE ACCESS

    This study examined a novel intrabody communication method using magnetic coupling. For designing transceivers utilizing this communication method, it is important to understand the power-transfer characteristic between the sending and receiving coils of the transceivers and to develop a technique for maximizing the transceiver efficiency. This study targeted a two-coil wireless power-transfer system with an L-section matching network. The computer simulation results showed that 1) the maximum power-transfer efficiency (PTE) was obtained by adjusting the matching network, and 2) the optimal PTE was achievable. In addition, this study conducted experiments and derived similar results from part of the simulation. The proposed wireless power-transfer system is promising as a magnetic intrabody communication system.

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  • Chi Zhang, Pu-wen Lei, Koji Koyamada
    2019 Volume 6 Issue 2 Pages 317-330
    Published: 2019
    Released on J-STAGE: August 31, 2019
    JOURNAL FREE ACCESS

    In this paper, a system used for calculating the threshold values of extreme precipitation events and extracting these events is proposed. The threshold calculation algorithms are based on four improved percentile methods and the system selects an optimal method automatically during the calculation. In addition, the precipitation data of every year is divided into four parts according to the season. Therefore, precipitation threshold for each season is calculated and used for comparison. In experiments, the system is applied to the simulation data of precipitations from 2051 to 2111 and the variation trend of the precipitations is analyzed.

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  • Sakiko Ogawa, Taro Kanno, Kazuo Furuta
    2019 Volume 6 Issue 2 Pages 331-353
    Published: 2019
    Released on J-STAGE: August 31, 2019
    JOURNAL FREE ACCESS

    Shared situational awareness among air-traffic controllers (ATCOs) and pilots is essential for airport safety. This paper presents models and simulations of cognitive activities that underlie the communications between ATCOs and pilots. This model facilitates the shared situational awareness analysis and can produce quantitative data to inform the design of communications protocols. A simulation using data from the official 1977-Tenerife-accident report, which reveals the cognitive processes that could explain the communications and behavior detailed in the report, suggests alternate explanations. This proof-of-concept test suggests that the proposed model and simulations can be used for analyzing air-traffic control accidents at airports.

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  • Suphanut Kongwat, Hiroshi Hasegawa
    2019 Volume 6 Issue 2 Pages 354-366
    Published: 2019
    Released on J-STAGE: August 31, 2019
    JOURNAL FREE ACCESS

    Topology optimization is one complex method due to a final layout obtained by an initial shape is not a consideration. This paper purposes a proportional technique to determine an optimal layout by employing the topology optimization method. The objective function is to maximize an internal energy density by stress constraint based on the bi-linear elastoplasticity material properties. Fully stress design criterion is concerned to be a factor of the proportional technique for updating the design variable. Finally, the optimal layout acquires from the proportional technique and results are faster to converge with an over-relaxation factor which applied to the fully stress design.

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  • Reza Arfa, Rubiyah Yusof, Parvaneh Shabanzadeh
    2019 Volume 6 Issue 2 Pages 367-385
    Published: 2019
    Released on J-STAGE: October 04, 2019
    JOURNAL FREE ACCESS

    Quantifying dissimilarity between two trajectories is a challenging problem yet it is a fundamental task with a wide range of applications. Existing dissimilarity measures are computationally expensive to calculate. We proposed a dissimilarity measure estimate for trajectory data based on deep learning methodology. One advantage of the proposed method is that it can get executed on GPU, which can significantly reduce the execution time for processing a large number of data. The proposed network is trained using synthetic data. A trajectory simulator that generates random trajectories is proposed. We used a publicly available dataset to evaluate the proposed method for the task of trajectory clustering. Our experiments show the performance of the proposed dissimilarity estimation method is comparable with well-known methods while our method is substantially faster to compute.

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  • Hiroshi Serizawa, Takashi Amemiya, Kiminori Itoh
    2019 Volume 6 Issue 2 Pages 386-415
    Published: 2019
    Released on J-STAGE: November 07, 2019
    JOURNAL FREE ACCESS

    In the previous paper, we prepared the Poisson Equation and the Inhomogeneous Permeability Models (PEM & IPM) that can create tree-shaped networks under the conditions of homogeneous or inhomogeneous permeability. The driving force of channel network formation is derived from two-dimensional Poisson equations in both models, the solutions of which are supposed to represent a gravitational pressure field. Particularly important is the latter IPM that succeeds to simulate seemingly natural and realistic river channel basins, in which regional fluctuations of geographical properties concerning soil, precipitation and vegetation are reflected by inhomogeneous permeability. However, we did not refer to the relationship with the Horton's law and the identification of fractal dimensions. This paper examines the consistency with the Horton's law and the measurement of fractal dimensions in tree network systems generated by IPMs under the more improved resolution. Our numerical simulations show good accordance with the Horton's law, however, the calculation of fractal dimensions using the bifurcation and length ratios is not satisfactory because of a large uncertainty. Then, we originally propose an alternative method, referred to as the “extended cluster dimension”, which makes possible to identify the exact value of fractal dimensions in river network systems.

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