JaLCDOI 10.18926/17839
FullText URL Mem_Fac_Eng_OU_43_49.pdf
Author Akamatsu, Shinya| Konishi, Masami| Imai, Jun|
Abstract In this paper, the controlled target is the SCARA robot with two links, and the object is fine control of the arm head position of the robot. To attain the object, Internal Model Control (IMC) is introduced. A nonlinear equations are for robot dynamics formulated by solving Lagrange equation, and is linearized to design control system by IMC. The controller of IMC is designed or synthesisted as the inverse system of the linearized model, and IMC filter model is selected. Also, reference filter is introduced to make the improvement of performance. The result of control performance by IMC is compared with that of PID numerically, accuracy and incoherency are confirmed.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 49
End Page 54
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308854
JaLCDOI 10.18926/17837
FullText URL Mem_Fac_Eng_OU_43_39.pdf
Author Kuwashima, Takayuki| Imai, Jun| Konishi, Masami|
Abstract This paper presents method of the controller design for one link arm with parametric uncertainty. Recently, many manufacturing robots are operated in manufacturing facilities, with the aim of labor and cost saving or improvement of the productivity. Such robots need to have positioning performance of high precision. In condition that there is an uncertainty in plant dynamics, desired control performance may not be attained because the controller is designed according to the mathematical model of a plant. So it is important that the designed control system have a robust control performance. In this paper, the robust controller is designed using Quantitative Feedback Theory (QFT) for one link arm with parametric uncertainty. Simulation experiments are run for control system designed by using QFT and conventional method. The results are compared with each other and it is found that the control system designed by QFT shows a robust performance and can suppress the unevenness of output against parametric uncertainty.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 39
End Page 48
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308875
JaLCDOI 10.18926/17835
FullText URL Mem_Fac_Eng_OU_43_32.pdf
Author Mabuchi, Shuji| Konishi, Masami| Imai, Jun|
Abstract A tractor-trailer vehicle in the factory might move on the route determined beforehand. However, automation of a tractor-trailer vehicle is difficult so that it is necessary to consider the nonlinearity of a vehicle and a trailer. In this research, the effective tracking control method of a tractor-trailer vehicle is proposed. The control method using time-state control form for a preview control is presented, and be applied a tractor-trailer vehicle with nonholonomic characteristics. Results of numerical experiments are presented to check effectiveness of the proposed control method.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 32
End Page 38
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308736
JaLCDOI 10.18926/17833
FullText URL Mem_Fac_Eng_OU_43_27.pdf
Author Totsuji, Hiroo|
Abstract When the Coulomb coupling between fine particles becomes sufficiently strong in fine particle plasmas, the isothermal compressibility of the whole system diverges and we have a phase separation and an associated critical point. Experimental conditions of fine particle plasmas, densities and temperatures of components and the fine particle size, are obtained corresponding to characteristic parameters around the critical point and the dependency on ion species and other factors is discussed.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 27
End Page 31
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308947
JaLCDOI 10.18926/17831
FullText URL Mem_Fac_Eng_OU_43_22.pdf
Author Totsuji, Hiroo| Chai Hong| Totsuji, Chieko| Tsuruta, Kenji|
Abstract For the transfer of quantum information and the creation of entangled states, the application of tuned spin chains, systems of spins with the nearest-neighbor coupling tuned so as to give high efficiency, has been proposed and some examples of high performance have been given by several authors. In this article, the effect of deviations from tuned values and the effect of resultant asymmetry are investigated through numerical simulations and theoretical analyses. It is shown that there exists a system where the transfer efficiency is comparable with exactly tuned ones and, at the same time, robust to noises in the coupling constants. It is also shown that the effect of asymmetry on the efficiency of entanglement creation is of the second order when the asymmetry is small.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 22
End Page 26
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308966
JaLCDOI 10.18926/17829
FullText URL Mem_Fac_Eng_OU_43_16.pdf
Author Kurose Tomoyuki| Tsuruta, Kenji| Totsuji, Chieko| Totsuji, Hiroo|
Abstract The finite-difference time-domain (FDTD) method has been applied to the calculation of the phonon band structure of two-dimensional (2D) phononic crystals, consisting of metal cylinders placed periodically in liquid. By comparing several combinations of materials for metal cylinder and liquid, we analyze the dependence of the band structures on sound speed and density of liquid media. Moreover, the negative refraction of the acoustic waves is observed at the interfaces between phononic crystal slab and the liquid. We find that an acoustic“lens effect”with the slab appears due to the negative refractions. The relationship between the focal intensity in the lens effect and the band structure is discussed.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 16
End Page 21
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308928
JaLCDOI 10.18926/17826
FullText URL Mem_Fac_Eng_OU_43_8.pdf
Author Umeda Ryosuke| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo|
Abstract Metamaterial which has negative permittivity and permeability is investigated via computer simulations. Effects of the nanostructure on dielectric and magnetic properties of the material are taken into account by introducing the Drude-Lorentz model in the materials dispersion. We include multi-band process in the dielectric response in order to reproduce accurately experimental values of bulk Au thin film. Size effect on the dispersion is examined by comparing the model with that of a noble metal particle. Based on the dispersion model constructed, we analyze the electromagnetic response of nanostructured metamaterials to evanescent waves at microwave and optical frequencies via finite-difference time-domain simulatioins on parallel computer. A re- focusing and an amplification of the evanescent waves propagating through a metamaterial, consisting of metal slab/vacuum stacking, is demonstrated for the frequencies of 30GHz and 744THz.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2009-01
Volume volume43
Start Page 8
End Page 15
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308833
JaLCDOI 10.18926/19953
FullText URL Mem_Fac_Eng_OU_44_1.pdf
Author Nagai Shinji| Umeda Ryosuke| Tsuruta, Kenji|
Abstract In this paper, we investigate a light-confinement phenomenon in the structure which has triangular latice composed of Double NeGative Metamaterial (DNGM). In geometrical optics consideration, this structure is expected to confine lights completely by sequential refractions in the structure. We demonstrate it by using the two dimensional finite-difference time-domain simulations. We introduce Drude-Lorentz model for dielectric and magnetic dispersion of the material at optical frequencies. We analyze quantitatively the effects of energy loss in the DNGM on the light-confinement efficiency.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 1
End Page 6
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309117
JaLCDOI 10.18926/19962
FullText URL Mem_Fac_Eng_OU_44_73.pdf
Author Imanaka, Hiroyuki| Tanaka, Soukichi| Feng, Bin| Imamura, Koreyoshi| Nakanishi, Kazuhiro|
Abstract We used modified Czapek-Dox (mCD) or dextrin-peptone-yeast extract (DPY) media to cultivate a filamentous fungus, Aspergillus oryzae IAM 2706 by three different cultivation methods, i.e., shaking-flask culture (SFC), agar-plate culture (APC), and membrane-surface liquid culture (MSLC), to identify the differences in cultivation behaviors and gene transcriptional profiles. The fungi cultivated by APC or MSLC secreted a greater number of different proteins/enzymes in larger quantities compared with fungi cultivated by SFC, particularly when DPY medium was used. In particular, the amounts of protease secreted by fungi cultivated via MSLC or APC were much greater compared with SFC. When mCD medium was used, α-amylase activity was barely detectable in all cultures while the activity was detected in MSLC and APC in a quantity that was several times higher than that in SFC using DPY medium. SDS-PAGE analysis and N-terminal amino acid sequences confirmed 6 proteins in the culture supernatants when DPY medium was used. Among these proteins oryzin (an alkaline protease) and α-amylase were detected at much higher levels in APC and MSLC compared with SFC, which was consistent with the measured activity of the secreted enzymes. However, when mCD medium was used, only oryzin was detected in significant amounts in MSLC and APC. Microarray analyses of the fungi cultivated by SFC, APC or MSLC using either mCD or DPY media indicated that the gene transcriptional profile of the MSLC sample was similar to that of the APC sample but different from that of the SFC sample. When mCD medium was used, most of the genes that were up-regulated 10-folds or greater in the MSLC sample relative to the SFC sample were unknown or predicted proteins. Transcription of the oryzin gene was only slightly up-regulated in the MSLC sample while transcription of the α-amylase gene was slightly down-regulated. On the other hand, when DPY medium was used, many known genes including the oryzin gene were up-regulated in the MSLC sample versus the SFC sample.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 73
End Page 83
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309053
JaLCDOI 10.18926/19961
FullText URL Mem_Fac_Eng_OU_44_69.pdf
Author Nekado, Kenta| Kato, Hidehiro| Nogami, Yasuyuki| Morikawa, Yoshitaka|
Abstract Recently, pairing–based cryptographies have attracted much attention. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field should be efficient. Especially for final exponentiation included in pairing calculation, squaring is more important than multiplication. This paper proposes an efficient squaring algorithm in extension field for Freeman curve.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 69
End Page 72
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309070
JaLCDOI 10.18926/19960
FullText URL Mem_Fac_Eng_OU_44_60.pdf
Author Nogami, Yasuyuki| Morikawa, Yoshitaka|
Abstract This paper proposes a method for generating a certain composite order ordinary pairing–friendly elliptic curve of embedding degree 3. In detail, the order has two large prime factors such as the modulus of RSA cryptography. The method is based on the property that the order of the target pairing–friendly curve is given by a polynomial as r(X) of degree 2 with respect to the integer variable X. When the bit size of the prime factors is about 500 bits, the proposed method averagely takes about 15 minutes on Core 2 Quad (2.66Hz) for generating one.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 60
End Page 68
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309063
JaLCDOI 10.18926/19959
FullText URL Mem_Fac_Eng_OU_44_50.pdf
Author Kanatani, Kenichi| Niitsuma Hirotaka| Rangrajan Prasanna|
Abstract We present highly accurate least-squares (LS) alternatives to the theoretically optimal maximum likelihood (ML) estimator for homographies between two images. Unlike ML, our estimators are non-iterative and yield solutions even in the presence of large noise. By rigorous error analysis, we derive a “hyperaccurate” estimator which is unbiased up to second order noise terms. Then, we introduce a computational simplification, which we call “Taubin approximation”, without incurring a loss in accuracy. We experimentally demonstrate that our estimators have accuracy surpassing the traditional LS estimator and comparable to the ML estimator.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 50
End Page 59
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002308986
JaLCDOI 10.18926/19958
FullText URL Mem_Fac_Eng_OU_44_42.pdf
Author Kanatani, Kenichi| Rangrajan Prasanna|
Abstract This paper presents a new method for fitting an ellipse to a point sequence extracted from images. It is widely known that the best fit is obtained by maximum likelihood. However, it requires iterations, which may not converge in the presence of large noise. Our approach is algebraic distance minimization; no iterations are required. Exploiting the fact that the solution depends on the way the scale is normalized, we analyze the accuracy to high order error terms with the scale normalization weight unspecified and determine it so that the bias is zero up to the second order. We demonstrate by experiments that our method is superior to the Taubin method, also algebraic and known to be highly accurate.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 42
End Page 49
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309054
JaLCDOI 10.18926/19957
FullText URL Mem_Fac_Eng_OU_44_32.pdf
Author Kanatani, Kenichi| Niitsuma Hirotaka| Sugaya Yasuyuki|
Abstract We present an alternative approach to what we call the “standard optimization”, which minimizes a cost function by searching a parameter space. Instead, the input is “orthogonally projected” in the joint input space onto the manifold defined by the “consistency constraint”, which demands that any minimal subset of observations produce the same result. This approach avoids many difficulties encountered in the standard optimization. As typical examples, we apply it to line fitting and multiview triangulation. The latter produces a new algorithm far more efficient than existing methods. We also discuss optimality of our approach.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 32
End Page 41
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309124
JaLCDOI 10.18926/19956
FullText URL Mem_Fac_Eng_OU_44_24.pdf
Author Kanatani, Kenichi| Sugaya Yasuyuki|
Abstract We present an improved version of the MSL method of Sugaya and Kanatani for multibody motion segmentation. We replace their initial segmentation based on heuristic clustering by an analytical computation based on GPCA, fitting two 2-D affine spaces in 3-D by the Taubin method. This initial segmentation alone can segment most of the motions in natural scenes fairly correctly, and the result is successively optimized by the EM algorithm in 3-D, 5-D, and 7-D. Using simulated and real videos, we demonstrate that our method outperforms the previous MSL and other existing methods. We also illustrate its mechanism by our visualization technique.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 24
End Page 31
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309159
JaLCDOI 10.18926/19955
FullText URL Mem_Fac_Eng_OU_44_13.pdf
Author Kanatani, Kenichi| Sugaya Yasuyuki|
Abstract A new numerical scheme is presented for computing strict maximum likelihood (ML) of geometric fitting problems having an implicit constraint. Our approach is orthogonal projection of observations onto a parameterized surface defined by the constraint. Assuming a linearly separable nonlinear constraint, we show that a theoretically global solution can be obtained by iterative Sampson error minimization. Our approach is illustrated by ellipse fitting and fundamental matrix computation. Our method also encompasses optimal correction, computing, e.g., perpendiculars to an ellipse and triangulating stereo images. A detailed discussion is given to technical and practical issues about our approach.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 13
End Page 23
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309170
JaLCDOI 10.18926/19954
FullText URL Mem_Fac_Eng_OU_44_7.pdf
Author Maetani Noriaki| Kurose Tomoyuki| Tsuruta, Kenji|
Abstract The lens effect of acoustic waves in a two-dimensional (2D) phononic crystal is studied by numerical simulation based on the finite-difference time-domain (FDTD) method. We calculate the phonon band structure of 2D phononic crystals, consisting of metal cylinders placed periodically in water. Lens effect is observed by the negative refraction of acoustic waves, which results in refocusing of the waves at the point outside the crystal. To increase the focal intensity, we introduce a 2D phononic crystal shield with a different composition of material, which returns the incident waves back to the lens via the perfect reflection. Also, the dependence on filling fraction of metal in the crystal is studied.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2010-01
Volume volume44
Start Page 7
End Page 12
ISSN 1349-6115
language 英語
File Version publisher
NAID 120002309019
JaLCDOI 10.18926/44498
FullText URL mfe_045_036_045.pdf
Author Kanatani, Kenichi| Niitsuma, Hirotaka|
Abstract We present a new method for optimally computing the 3-D rotation from two sets of 3-D data. Unlike 2-D data, the noise in 3-D data is inherently inhomogeneous and anisotropic, reflecting the characteristics of the 3-D sensing used. To cope with this, Ohta and Kanatani introduced a technique called “renormalization”. Following them, we represent a 3-D rotation in terms of a quaternion and compute an exact maximum likelihood solution using the FNS of Chojnacki et al. As an example, we consider 3-D data obtained by stereo vision and optimally compute the 3-D rotation by analyzing the noise characteristics of stereo reconstruction. We show that the widely used method is not suitable for 3-D data. We confirm that the renormalization of Ohta and Kanatani indeed computes almost an optimal solution and that, although the difference is small, the proposed method can compute an even better solution.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2011-01
Volume volume45
Start Page 36
End Page 45
ISSN 1349-6115
language 英語
Copyright Holders Copyright © by the authors
File Version publisher
NAID 80021759250
JaLCDOI 10.18926/44497
FullText URL mfe_045_027_036.pdf
Author Kanatani, Kenichi| Sugaya, Yasuyuki|
Abstract We describe in detail the algorithm of bundle adjustment for 3-D reconstruction from multiple images based on our latest research results. The main focus of this paper is on the handling of camera rotations and the efficiency of computation and memory usage when the number of variables is very large; an appropriate consideration of this is the core of the implementation of bundle adjustment. Computing the fundamental matrix from two views and reconstructing the 3-D structure from multiple views, we evaluate the performance of our algorithm and discuses technical issues of bundle adjustment implementation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2011-01
Volume volume45
Start Page 27
End Page 35
ISSN 1349-6115
language 英語
Copyright Holders Copyright © by the authors
File Version publisher
NAID 80021759249
JaLCDOI 10.18926/44496
FullText URL mfe_045_015_026.pdf
Author Kanatani, Kenichi| Rangrajan, Prasanna| Sugaya, Yasuyuki| Niitsuma, Hirotaka|
Abstract We present a new least squares (LS) estimator, called “HyperLS”, specifically designed for parameter estimation in computer vision applications. It minimizes the algebraic distance under a special scale normalization, which is derived by rigorous error analysis in such a way that statistical bias is removed up to second order noise terms. Numerical experiments suggest that our HyperLS is far superior to the standard LS and comparable in accuracy to maximum likelihood (ML), which is known to produce highly accurate results in image applications but may fail to converge if poorly initialized. Our HyperLS is a perfect candidate for ML initialization. In addition, we discuss how image-based inference problems have different characteristics form conventional statistical applications, with a view to serving as a bridge between mathematicians and computer engineers.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2011-01
Volume volume45
Start Page 15
End Page 26
ISSN 1349-6115
language 英語
Copyright Holders Copyright © by the authors
File Version publisher
NAID 120002905952