Journal of Computational Science and Technology
Online ISSN : 1881-6894
ISSN-L : 1881-6894
Volume 4, Issue 1
Displaying 1-6 of 6 articles from this issue
Papers
  • Takeshi UEDA, Kanji TANAKA
    2010 Volume 4 Issue 1 Pages 1-10
    Published: 2010
    Released on J-STAGE: January 26, 2010
    JOURNAL FREE ACCESS
    Map-matching is an effective approach for robot localization using large-size landmark maps. Existing map-matching techniques typically address batch localization applications where the objective maps are given prior to the map-matching task. In contrast to the existing techniques, this paper addresses real-time localization applications where the maps can be incrementally updated even during the map-matching task. We present a solution that combines an incremental RANSAC map-matching with an ANN landmark database. Experiments using real data show promising results.
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  • Yuichi TADANO, Hirohisa NOGUCHI
    2010 Volume 4 Issue 1 Pages 11-24
    Published: 2010
    Released on J-STAGE: February 16, 2010
    JOURNAL FREE ACCESS
    A formulation of a novel in-plane generalized finite element, which can be used in geometrically nonlinear analysis, is presented and some analyses are conducted using the proposed element. The presented element has four nodes, and four additional degrees of freedom are added on each node. As a result, this element can reproduce the quadratic deformation mode with only corner nodes and has no linear dependency, which is a well known problem of generalized finite elements. The formulation is based on the rate form of the virtual work principle and is obtained by a simple extension of the standard FEM. The convergence of the analysis solution and its robustness for element distortion are investigated, and the results are compared with those of standard-displacement-based first- and second-order elements. The proposed element provides solution convergence as good as or better than those of the conventional second-order elements. In addition, it is shown that an accurate solution is obtained when the mesh is strongly distorted.
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  • Sunao TOKURA, Ichiro HAGIWARA
    2010 Volume 4 Issue 1 Pages 25-35
    Published: 2010
    Released on J-STAGE: March 30, 2010
    JOURNAL FREE ACCESS
    Honeycomb panel is widely used as flooring or wall material in various structure including buildings, aircraft, train and so on due to high stiffness and lightness at present. Honeycomb panel, however, has a disadvantage that adhesive used to glue honeycomb core and top plate may burn by fire. On the other hand truss core panel has equivalent stiffness as honeycomb panel and is expected to be an alternative to honeycomb panel as it is safer for fire. However, in general, difficulty exists to form truss core and forming techniques should be developed for practice use of truss core panel. In this paper, firstly theoretical forming limitation is discussed for tetrahedral truss core . Secondly single stage forming simulation of truss core panel using explicit FEM technique was performed for preliminary investigation to estimate formability and thickness distribution. Finally multi-stage forming simulation was presented and possibility to apply press forming for truss core panel production through the simulation. In addition some results of the simulation was compared with the experiment and good agreement of both results was shown.
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  • Koji SHIMOYAMA, Kazuyuki SUGIMURA, Shinkyu JEONG, Shigeru OBAYASHI
    2010 Volume 4 Issue 1 Pages 36-50
    Published: 2010
    Released on J-STAGE: April 13, 2010
    JOURNAL FREE ACCESS
    Performance maps, which represent relations between performance and geometry parameters, are essential for engineers to make a first decision on preliminary specification of a product to be designed. However, actual design often needs to consider various performance and geometry parameters simultaneously. Therefore, the resulting performance maps must be constructed in a high-dimensional form. Based on these requirements, this paper proposes and demonstrates performance map construction with the aid of data mining techniques. Data mining can reveal characteristic patterns in high-dimensional data with performance and geometry parameters. Therefore, the data mining results make it easy to interpret complex features of performance vs. geometry relations, and help engineers to discover new knowledge for engineering design through interpretation. The present demonstration of a centrifugal diffuser demonstrated that the data mining techniques are suitable and applicable to high-dimensional performance map construction, together with actual acquisition of new knowledge for diffuser design that was unknown from conventional quasi-one-dimensional nozzle theory.
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  • Kazem GHABRAIE, Yi Min XIE, Xiaodong HUANG, Gang REN
    2010 Volume 4 Issue 1 Pages 51-63
    Published: 2010
    Released on J-STAGE: May 21, 2010
    JOURNAL FREE ACCESS
    Design of support system and selecting an optimum shape for the opening are two important steps in designing excavations in rock masses. Currently selecting the shape and support design are mainly based on designer's judgment and experience. Both of these problems can be viewed as material distribution problems where one needs to find the optimum distribution of a material in a domain. Topology optimization techniques have proved to be useful in solving these kinds of problems in structural design. Recently the application of topology optimization techniques in reinforcement design around underground excavations has been studied by some researchers. In this paper a three-phase material model will be introduced changing between normal rock, reinforced rock, and void. Using such a material model both problems of shape and reinforcement design can be solved together. A well-known topology optimization technique used in structural design is bi-directional evolutionary structural optimization (BESO). In this paper the BESO technique has been extended to simultaneously optimize the shape of the opening and the distribution of reinforcements. Validity and capability of the proposed approach have been investigated through some examples.
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  • Hiroya MAMORI, Koji FUKAGATA
    2010 Volume 4 Issue 1 Pages 64-75
    Published: 2010
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    A consistent scheme for computation of the Reynolds stress and turbulent kinetic energy budgets is proposed for incompressible turbulent flow simulation using the finite difference method on a nonuniform staggered grid system. The present scheme is derived from the Navier-Stokes equation discretized by using the second-order energy-conservative finite differential method. The Reynolds stress and turbulent kinetic energy budgets in a fully developed channel flow computed by using the proposed schemes are compared with those by using the consistent scheme proposed for a uniform grid [Suzuki and Kawamura, Trans. JSME/B, Vol. 60, No. 578 (1994), pp. 3280-3286] and an intuitive scheme. The residuals in the Reynolds normal stress and turbulent kinetic energy budgets computed by using the present scheme and Suzuki-Kawamura scheme are found to be both sufficiently small. We also apply the same idea to the discretization of Reynolds shear stress budget, although the consistency is imperfect, be derived the numerical test shows that the residual is slightly smaller than that computed by the other schemes.
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