JaLCDOI 10.18926/17851
フルテキストURL Mem_Fac_Eng_OU_43_108.pdf
著者 Nekado, Kenta| Kato, Hidehiro| Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 Recently, pairing-based cryptographies such as ID-based cryptography and group signature have been studied. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field must be efficiently carried out. The authors show efficient arithmetic operations of extension field for Xate pairing especially with Freeman curve.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2009-01
43巻
開始ページ 108
終了ページ 112
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002308904
JaLCDOI 10.18926/17853
フルテキストURL Mem_Fac_Eng_OU_43_113.pdf
著者 Sakemi, Yumi| Kato, hidehiro| Nogami, Yasuyuki| Morikawa, Yoshikawa|
抄録 Barreto–Naehrig (BN) curve has been introduced as an efficient pairing-friendly elliptic curve over prime field F(p) whose embedding degree is 12. The characteristic and Frobenius trace are given as polynomials of integer variable X. The authors proposed an improvement of Miller's algorithm of twisted Ate pairing with BN curve by applying X of small hamming weight in ITC–CSCC2008; however, its cost evaluation has not been explicitly shown. This paper shows the detail of the cost evaluation.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2009-01
43巻
開始ページ 113
終了ページ 116
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002308945
JaLCDOI 10.18926/19960
フルテキストURL Mem_Fac_Eng_OU_44_60.pdf
著者 Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 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.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2010-01
44巻
開始ページ 60
終了ページ 68
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002309063
JaLCDOI 10.18926/19961
フルテキストURL Mem_Fac_Eng_OU_44_69.pdf
著者 Nekado, Kenta| Kato, Hidehiro| Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 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.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2010-01
44巻
開始ページ 69
終了ページ 72
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002309070
JaLCDOI 10.18926/44499
フルテキストURL mfe_045_046_053.pdf
著者 Nogami, Yasuyuki| Yanagi, Erika| Izuta, Tetsuya| Morikawa, Yoshitaka|
抄録 Recently, composite order pairing–based cryptographies have received much attention. The composite order needs to be as large as the RSA modulus. Thus, they require a certain pairing–friendly elliptic curve that has such a large composite order. This paper proposes an efficient algorithm for generating an ordinary pairing–friendly elliptic curve of the embedding degree 1 whose order has two large prime factors as the RSA modulus. In addition, the generated pairing–friendly curve has an efficient structure for the Gallant–Lambert–Vanstone (GLV) method.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2011-01
45巻
開始ページ 46
終了ページ 53
ISSN 1349-6115
言語 English
著作権者 Copyright © by the authors
論文のバージョン publisher
NAID 120002905955
JaLCDOI 10.18926/44500
フルテキストURL mfe_045_054_059.pdf
著者 Nekado, Kenta| Takai, Yusuke| Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 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 considers squaring algorithms efficient for cubic extension field which is often used for pairing implementaions.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2011-01
45巻
開始ページ 54
終了ページ 59
ISSN 1349-6115
言語 English
著作権者 Copyright © by the authors
論文のバージョン publisher
NAID 80021759252
JaLCDOI 10.18926/46982
フルテキストURL mfe_37_2_073_087.pdf
著者 Nogami, Yasuyuki| Morikawa, Yoshitaka|
抄録 Public key cryptosystem has many uses, such as to sign digitally, to realize electronic commerce. Especially, RSA public key cryptosystem has been the most widely used, but its key for ensuring sufficient security reaches about 2000 bits long. On the other hand, elliptic curve cryptosystem(ECC) has the same security level with about 7-fold smaller length key. Accordingly, ECC has been received much attention and implemented on various processors even with scarce computation resources. In this paper, we deal with an elliptic curve which is defined over extension field F(p2c) and has a prime order, where p is the characteristic and c is a non negative integer. In order to realize a fast software implementation of ECC adopting such an elliptic curve, a fast implementation method of definition field F(p2c) especially F(p8) is proposed by using a technique called successive extension. First, five fast implementation methods of base field F(p2) are introduced. In each base field implementation, calculation costs of F(p2)-arithmetic operations are evaluated by counting the numbers of F(p)-arithmetic operations. Next, a successive extension method which adopts a polynomial basis and a binomial as the modular polynomial is proposed with comparing to a conventional method. Finally, we choose two prime numbers as the characteristic, and consider several implementations for definition field F(p8) by using five base fields and two successive extension methods. Then, one of these implementations is especially selected and implemented on Toshiba 32-bit micro controller TMP94C251(20MHz) by using C language. By evaluating calculation times with comparing to previous works, we conclude that proposed method can achieve a fast implementation of ECC with a prime order.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2003-03
37巻
2号
開始ページ 73
終了ページ 87
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 80015999992
JaLCDOI 10.18926/49321
フルテキストURL mfe_047_019_024.pdf
著者 Nogami, Yasuyuki| Sumo, Taichi|
抄録 Recent efficient pairings such as Ate pairing use two efficient rational point subgroups such that π(P) = P and π(Q) = [p]Q, where π, p, P, and Q are the Frobenius map for rational point, the characteristic of definition field, and torsion points for pairing, respectively. This relation accelerates not only pairing but also pairing–related operations such as scalar multiplications. It holds in the case that the embedding degree k divides r − 1, where r is the order of torsion rational points. Thus, such a case has been well studied. Alternatively, this paper focuses on the case that the degree divides r + 1 but does not divide r − 1. Then, this paper shows a multiplicative representation for r–torsion points based on the fact that the characteristic polynomial f(π) becomes irreducible over Fr for which π also plays a role of variable.
キーワード pairing–friendly curve torsion point group structure rank
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2013-01
47巻
開始ページ 19
終了ページ 24
ISSN 1349-6115
言語 English
著作権者 Copyright © by the authors
論文のバージョン publisher
NAID 120005232373
JaLCDOI 10.18926/49322
フルテキストURL mfe_047_025_032.pdf
著者 Nekado, Kenta| Takai, Yusuke| Nogami, Yasuyuki|
抄録 Pairing–based cryptosystems are well implemented with Ate–type pairing over Barreto–Naehrig (BN) curve. Then, for instance, their securities depend on the difficulty of Discrete Logarithm Problem (DLP) on the so–denoted G3 over BN curve. This paper, in order to faster solve the DLP, first proposes to utilize Gauss period Normal Basis (GNB) for Pollard’s rho method, and then considers to accelerate the solving by an adoption of lazy random walk, namely tag tracing technique proposed by Cheon et al.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2013-01
47巻
開始ページ 25
終了ページ 32
ISSN 1349-6115
言語 English
著作権者 Copyright © by the authors
論文のバージョン publisher
NAID 120005232374
JaLCDOI 10.18926/49320
フルテキストURL mfe_047_001_018.pdf
著者 Kanatani, Kenichi|
抄録 We summarize techniques for optimal geometric estimation from noisy observations for computer vision applications. We first discuss the interpretation of optimality and point out that geometric estimation is different from the standard statistical estimation. We also describe our noise modeling and a theoretical accuracy limit called the KCR lower bound. Then, we formulate estimation techniques based on minimization of a given cost function: least squares (LS), maximum likelihood (ML), which includes reprojection error minimization as a special case, and Sampson error minimization. We describe bundle adjustment and the FNS scheme for numerically solving them and the hyperaccurate correction that improves the accuracy of ML. Next, we formulate estimation techniques not based on minimization of any cost function: iterative reweight, renormalization, and hyper-renormalization. Finally, we show numerical examples to demonstrate that hyper-renormalization has higher accuracy than ML, which has widely been regarded as the most accurate method of all. We conclude that hyper-renormalization is robust to noise and currently is the best method.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2013-01
47巻
開始ページ 1
終了ページ 18
ISSN 1349-6115
言語 English
著作権者 Copyright © by the authors
論文のバージョン publisher
NAID 120005232372
JaLCDOI 10.18926/14158
フルテキストURL Mem_Fac_Eng_39_1_93.pdf
著者 五百旗頭 健吾| 豊田 啓孝| 和田 修己| 古賀 隆治|
抄録 The optical properties of clouds were measured with a polarization Mie lidar during April, 2004 and investigated to categorize the particles detected by the lidar. The cloud layers were categorized into five types according to the depolarization ratios, as follows: (I) constant and small (less than 5%); increasing with height (II) nearly from 0% and (III) from about 50%; (IV) large and varying with the backscattering coefficient; and (V) sharply decreasing. This categorization of clouds enabled us to separate aerosols from clouds in a lidar signal. Comparison of the backscattering coefficients between clouds of types (I) and (II) suggested that the depolarization ratio induced by multiple scattering in dense clouds does not depend on the particle density. Estimation of the particle phase for the five cloud categories was also examined.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2005-01
39巻
1号
開始ページ 93
終了ページ 101
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002308479
JaLCDOI 10.18926/15360
フルテキストURL Mem_Fac_Eng_OU_34_27.pdf
著者 Wei, He| 古賀 隆治| 五百旗頭 健吾| 和田 修己| 豊田 啓孝|
抄録 In spring of 1998, Asian dust was observed with a Mie LIDAR in Okayama University, which can measure depolarization ratio. Three events of intense Asian dust were occurred in the period and medially detailed structure of atmosphere was found after examining records. Asian dust was distinguished from water droplets and the possibility to study three dimensional dynamic structure of atmosphere were demonstrated.
キーワード Mie lidar Asian dust (KOSA) depolarization ratio backscattering ratio range normalized
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2000-03-27
34巻
1-2号
開始ページ 27
終了ページ 37
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307539
JaLCDOI 10.18926/46983
フルテキストURL mfe_37_2_089_097.pdf
著者 Iokibe, Kengo| Toyota, Yoshitaka| Wada, Osami| Koga, Ryuji|
抄録 Aerosol extinction coefficients of clouds and dust were continuously measured in the year of 2002 with a polarized Mie-scattering lidar controlled by an automatic and remotely operating system utilizing internet services. Measured cloud extinctions were greater than 1.0 km(-1) below the altitude 6 km, 0.17 - 1.0 km(-1) between 6 and 10 km, and 0.091 - 0.3 km(-1) beyond 10km. Extinction of dust were 0.10 and 0.20 km(-1) for Asian dust and 0.057 km(-1) for urban dust.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2003-03
37巻
2号
開始ページ 89
終了ページ 97
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120003457336
JaLCDOI 10.18926/46955
フルテキストURL mfe_38_1-2_091_096.pdf
著者 Kanayama, Naoki| Yamakoshi, Kimi| Kiyomi, Masaaki| Magari, Masaki| Ohmori, Hitoshi|
抄録 Generally, IgM antibodies (Abs) produced in a primary immune response show lower affinity for an inducing antigen (Ag) compared with the corresponding IgG Abs that are major switched isotypes formed in the secondary response. An IgM molecule is a pentamer with 10 Ag-binding sites that will contribute to an increase of avidity for an Ag. To estimate the contribution of the pentameric structure to the avidity of an IgM Ab, we generated IgM and IgG1 monoclonal Abs (mAbs) with identical V regions that are specific for 4-hydroxy-3-nitrophenylacetyl (NP) by in vitro class switching of B cells followed by the cell fusion with a mouse myeloma cell line. Compared with an anti-NP IgG1 mAb, the corresponding IgM mAb showed much higher avidity for NP-conjugated bovine serum albumin, which was drastically reduced after being dissociated into monomers.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2004-03
38巻
1-2号
開始ページ 91
終了ページ 96
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 80017001822
JaLCDOI 10.18926/47025
フルテキストURL mfe_36_2_051_060.pdf
著者 Hikida, Masaki| Magari, Masaki| Nakayama, Yasunori| Kanayama, Naoki| Ohmori, Hitoshi|
抄録 A population of peripheral B cells have been shown to express recombination activating gene products, RAG-1 and RAG-2, which are considered to be involved in revising the B cell antigen receptor (BCR) in the periphery. BCR engagement has been reported to turn off RAG expression in peripheral B cells, whereas the same treatment has an opposite effect in immature B cells in the bone marrow. In contrast to receptor editing that is involved in the removal of autoreactivity in immature B cells, it has been shown that secondary V(D)J rearrangement in peripheral B cells, termed receptor revision, contributes to affinity maturation of antibodies. Here, we show that RAG-2 expression in murine splenic B cells was abrogated by the coligation of BCR with complement receptors (CD21/CD35) much more efficiently than by the engagement of BCR alone. On the other hand, the same coligation augmented proliferation of anti-CD40-stimulated B cells. Consistent with these observations, RAG-2 expression was lower in the draining lymph nodes of the quasi-monoclonal mice when they were immunized with a high-affinity antigen than with a low-affinity one. These findings suggest a crucial role for CD21/CD35 in directing the conservation or the revision of BCRs in peripheral B cells.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2002-03
36巻
2号
開始ページ 51
終了ページ 60
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 80015582223
著者 Faculty of Engineering, Okayama University|
発行日 2012-01
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
46巻
資料タイプ その他
JaLCDOI 10.18926/19962
フルテキストURL Mem_Fac_Eng_OU_44_73.pdf
著者 Imanaka, Hiroyuki| Tanaka, Soukichi| Feng, Bin| Imamura, Koreyoshi| Nakanishi, Kazuhiro|
抄録 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.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 2010-01
44巻
開始ページ 73
終了ページ 83
ISSN 1349-6115
言語 English
論文のバージョン publisher
NAID 120002309053
著者 Faculty of Engineering, Okayama University|
発行日 2013-01
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
47巻
資料タイプ その他
JaLCDOI 10.18926/15391
フルテキストURL Mem_Fac_Eng_OU_27_1_33.pdf
著者 島田 行恭| 鈴木 和彦| 佐山 隼敏|
抄録 Neural nets have recently become the focus of much attention, largely because of their wide range of complex and nonlinear problems. This paper presents a new integrated approach using neural networks for diagnosing process failures. The fault propagation in process is modeled by causal relationships from the fault tree and its minimal cut sets. The measurement patterns required for training and testing the neural network were obtained from fault propagation model. The network is able to diagnose even in the presence of malfunction of certain sensors. We demonstrate via a nitric acid cooler process how the neural network can learn and successfully diagnose the faults.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1992-11-25
27巻
1号
開始ページ 33
終了ページ 44
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307902
JaLCDOI 10.18926/15414
フルテキストURL Mem_Fac_Eng_OU_26_1_27.pdf
著者 冨田 栄二| Nsunge Felix Chintu| 浜本 嘉輔|
抄録 Distributions of hydrogen gas concentration in a suddenly started, single shot hydrogen gas jet issuing from a 1 mm diameter injector into still air were measured using laser interferometry method. This unsteady, turbulent free jet flow has also been calculated using the two-equation, high Reynolds number version of k-ε turbulence model and hybrid scheme for treating combined diffusion and convection in the SIMPLE algorithm. The injection pressure was 0.5 MPa for which predicted and measured temporal jet tip penetration distributions indicate that the jet discharged into still air at Mach 0.25. The level of agreement between present prediction and measurement is good in some regions and poor in others.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1991-11-30
26巻
1号
開始ページ 27
終了ページ 41
ISSN 0475-0071
言語 English
論文のバージョン publisher
NAID 120002307648