| JaLCDOI | 10.18926/14155 |
|---|---|
| FullText URL | Mem_Fac_Eng_39_1_63.pdf |
| Author | Kanatani, Kenichi| |
| Abstract | Geometric fitting is one of the most fundamental problems of computer vision. In [8], the author derived a theoretical accuracy bound (KCR lower bound) for geometric fitting in general and proved that maximum likelihood (ML) estimation is statistically optimal. Recently, Chernov and Lesort [3] proved a similar result, using a weaker assumption. In this paper, we compare their formulation with the author’s and describe the background of the problem. We also review recent topics including semiparametric models and discuss remaining issues. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2005-01 |
| Volume | volume39 |
| Issue | issue1 |
| Start Page | 63 |
| End Page | 70 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002308366 |
| JaLCDOI | 10.18926/14156 |
|---|---|
| FullText URL | Mem_Fac_Eng_39_1_71.pdf |
| Author | Nogami, Yasuyuki| Morikawa, Yoshitaka| |
| Abstract | This paper proposes an algorithm for generating prime order elliptic curves over extension field whose extension degree is a power of 2. The proposed algorithm is based on the fact that the order of the twisted elliptic curve is able to be a prime number when the extension degree for the twist operation is a power of 2. When the definition field is F(2(40)−87)(4) , the proposed algorithm can generate a prime order elliptic curve within 5 seconds on PentiumIII (800MHz) with C language. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2005-01 |
| Volume | volume39 |
| Issue | issue1 |
| Start Page | 71 |
| End Page | 81 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002308036 |
| JaLCDOI | 10.18926/14157 |
|---|---|
| FullText URL | Mem_Fac_Eng_39_1_82.pdf |
| Author | Wang, Feng| Nogami, Yasuyuki| Morikawa, Yoshitaka| |
| Abstract | In this paper, we focus on developing a high-speed square root (SQRT) algorithm required for an elliptic curve cryptosystem. Examining Smart algorithm, the previously well-known SQRT algorithm, we can see that there is a lot of computation overlap in Smart algorithm and the quadratic residue (QR) test, which must be implemented prior to a SQRT computation. It makes Smart algorithm inefficient. The essence of our proposition is thus to present a new QR test and an efficient SQRT algorithm to avoid all the overlapping computations. The authors devised a SQRT algorithm for which most of the data required have been computed in the proposed QR test. Not only there is no computation overlap in the proposed algorithm and the proposed QR test, but also in the proposed algorithm over GF(p(2)) (4 | p − 1) some computations can be executed in GF(p); whereas in Smart algorithm over GF(p(2)) all the computations must be executed in GF(p(2)). These yield many reductions in the computational time and complexity. We implemented the two QR tests and the two SQRT algorithms over GF(pm) (m=1, 2) in C++ language with NTL (Number Theory Library) on Pentium4 (2.6GHz), where the size of p is around 160 bits. The computer simulations showed that the proposed QR test and the proposed algorithm over GF(p(m)) were about 2 times faster than the conventional QR test and Smart algorithm over GF(p(m)). |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2005-01 |
| Volume | volume39 |
| Issue | issue1 |
| Start Page | 82 |
| End Page | 92 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002308422 |
| JaLCDOI | 10.18926/14158 |
|---|---|
| FullText URL | Mem_Fac_Eng_39_1_93.pdf |
| Author | Iokibe, Kengo| Toyota, Yoshitaka| Wada, Osami| Koga, Ryuji| |
| Abstract | 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2005-01 |
| Volume | volume39 |
| Issue | issue1 |
| Start Page | 93 |
| End Page | 101 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002308479 |
| JaLCDOI | 10.18926/15164 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_41.pdf |
| Author | Kuroboshi, Manabu| Tanaka, Muneaki| Kishimoto, Suguru| Goto, Kentaro| Tanaka, Hideo| |
| Abstract | In 360 females, Bone mineral density (BMD) in lumbar vertebrae (L2-L4) was assessed by quantitative computed tomography (QCT), and the values obtained were compared with the frequency of vertebral transformation or fracture as assessed by lateral scan image (scanogram) by X-ray CT. A correlation was observed between the frequency of vertebral transformation (or fracture) and lumbar BMD values : BMD under 125 mg/cm(3) was observed over 90% of women with vertebral transformation, and BMD under 70mg/cm(3) was found about 50% of them. These results suggest that decrease in BMD in lumbar vertebrae leads to vertebral transformation or fracture. Thus, measurement of BMD by QCT would be very useful in predicting vertebral transformation or fractures. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 41 |
| End Page | 46 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307948 |
| JaLCDOI | 10.18926/15166 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_31_1_19.pdf |
| Author | Totsuji, Hiroo| Kishimoto, Tokunari| Totsuji, Chieko| |
| Abstract | As a model of dusty plasmas in external fields, Yuka.wa system in a one-dimensional external field is analyzed by molecular dynamics simulations and theoretical approaches. It is shown that particles form clear thin layers (sheets) at low temperatures and the number of layers changes discretely with characteristic parameters of the system, accompanying the rearrangements of whole system from nearly equipartitioned layers to also nearly equipartitioned layers. The number, positions and populations of layers are obtained as functions of characteristic parameters. The shell (sheet) model which has been successful for confined one-component plasmas is extended to this system and results of numerical experiments are reproduced to a good accuracy. The effect of cohesive energy in each layer is of essential importance to reproduce discrete changes in the number of sheets. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1996-12-27 |
| Volume | volume31 |
| Issue | issue1 |
| Start Page | 19 |
| End Page | 33 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307616 |
| JaLCDOI | 10.18926/15269 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_47.pdf |
| Author | Doumae, Yukihiro| Konishi, Masami| Imai, Jun| Asada, Hideki| Kitamura, Akira| |
| Abstract | In this paper, an identification method of motor parameters for the diagnosis of rotor bar defects in the squirrel cage induction motor is proposed. It is difficult to distinguish the degree of deterioration by a conventional diagnostic method such as Fourier analysis. To overcome the difficulty, a motor simulator is used to identify the degree of deterioration of rotors in the squirrel cage induction motor. Using this method, the deterioration of rotor bars in the motor can be estimated quantitatively. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 47 |
| End Page | 51 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307181 |
| JaLCDOI | 10.18926/15297 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_97.pdf |
| Author | Jindai, Mitsuru| Osaki, Hirokazu| Kajihara, Yasuhiro| Munesawa, Yoshiomi| Tano Masakazu| Okamoto Katsuyuki| Nishino Akira| Okamoto Asao| Nishimori Naoki| |
| Abstract | We propose the recognition method of bridge soldering base metal on the circuits by comparing CAD figure and input image of image processing to locate the soldering iron tip accurately to secure the high quality Firstly, three dimensional CAD assembly drawing of circuits which are assembled perpendicularly in each other is projected on an imaginary two dimensional screen which is vertical to the optical axis of the camera The projected image is used as the standard CAD figure to inspect the location of the bridge soldering base metal. The positions among the bridge soldering base metals show the line state. So this line (connecting line) is used as the reference line to inspect the location of the bridge soldering base metal. The characteristics of the standard figure are represented by the connecting line, edge line and center points of base metal. Secondly, the position and gradient of connecting line among bridge soldering base metals in the input image is estimated. And the position of base metal and assembly accuracy of circuit units are calculated by comparing the shape and position of each base metal with its standard figure based on the connecting line Furthermore, the length between the opposite edges of the base metals are calculated to inspect the positions and the assemble accuracy of circuit units. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 97 |
| End Page | 103 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307283 |
| JaLCDOI | 10.18926/15344 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_1.pdf |
| Author | Abe, Takeji| Hualin Song| Akagi Yasuo| Shimizu, Ichiro| |
| Abstract | Free surface of polycrystalline metal becomes roughened after plastic deformation. The surface roughening is closely related to the inhomogeneity of polycrystalline metals, that is, to the inhomogeneous plastic deformation of respective grains. In the present study, inhomogeneous deformation on the free surface of polycrystalline aluminum specimen during uniaxial tension is studied. The inhomogeneous deformation of grains in the central area of the free surface of specimen is observed by the laser scanning microscope, while the inhomogeneous deformation perpendicular to the surface is studied by the laser scanning microscope as well as the stylus measuring instrument. It is shown that the surface roughness and the strain of respective grains increase with the applied strain. Discussions are made on the change in the surface roughness, the strain in each grain and the slip-line angles with the applied strain. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 1 |
| End Page | 8 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307340 |
| JaLCDOI | 10.18926/15346 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_9.pdf |
| Author | Abe, Takeji| Tsuboi, Tomoaki| |
| Abstract | The evaluation of microscopic inhomogeneity of polycrystalline aluminum is performed by measuring the hardness in respective grains. The recently developed ultra-micro hardness tester is used and the effects of the test pattern, the indentation load and the indenting velocity are examined. Then, the relationship between the increase in the hardness caused by the work hardening and the deformation of respective grains are statistically investigated. The hardness testing mode in which the initial load is applied before the onset of measurement gives more stable results than the testing mode without the initial load. The test condition with the indentation load of 9.8mN and the indentation velocity of 0.2 μm/sec seems to be optimum and gives the least dispersion of the measured values in grains. It is shown that the hardness values of respective grains in polycrystalline aluminum as well as their dispersion increase with the applied plastic strain. Discussion is made on the microscopic deformation behavior of polycrystalline aluminum. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 9 |
| End Page | 19 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307825 |
| JaLCDOI | 10.18926/15348 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_21.pdf |
| Author | S.kovalenko, Volodymyr| Uno, Yoshiyuki| Okamoto, Yasuhiro| Anyakin, M.| Lutay, A.| Shubul, Khaled Al.| |
| Abstract | In electric power industry, there is a problem of achieving stable joint in different components using high productive and efficient technologies. One type of these components is packages of slices for magnetic circuit of electric motors, transformers etc., which need reliable means for their fixing. Laser welding is proposed to solve this problem as an alternative for existing technologies. The development of the laser welding process is presented based on process simulation, study of heat history and comparison with experimental results. Laser beam additional scanning technique is proposed to improve the quality and efficiency of the joining operation. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 21 |
| End Page | 28 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307424 |
| JaLCDOI | 10.18926/15350 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_29.pdf |
| Author | Shimamura, Kaoru| Munesawa Yuhji| Uchida, Tetsuya| |
| Abstract | Poly (ethylene-block-vinyl alcohol), which consisted of both hydrophobic and hydrophilic blocks, was prepared by using polyethylene single crystals as starting material. Polyethylene single crystals reacted with fuming nitric acid resulting in long methylene chains with functional groups such as COOH and NO(2) at the ends (the chain length were almost same as the lamellar thickness of polyethylene single crystal). The functionalized methylene chains were allowed to react with 4-aminostyrene to give corresponding amides, i.e., methylene chains with vinyl groups at the ends (macromer). The macromers were extended by block-copolymerization with vinyl acetate, then saponified resulting in PE/PVA block co-polymer. The block copolymer was molded into sheets which were subsequently heat-treated in contact with hydrophilic or hydrophobic media. Depending on the media, the sheet surface changed at high temperature reversibly from hydrophilic to hydrophobic and vice versa. The surface property was fixed by quenching because both blocks were able to crystallize. Thus the surface of this material can be tailored for various purposes at high temperature, and then used in stable at room temperature. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 29 |
| End Page | 34 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307155 |
| JaLCDOI | 10.18926/15352 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_35.pdf |
| Author | Shimamura, Kaoru| Uchida, Tetsuya| Inoue, Tomohiro| |
| Abstract | Rigid polymer, poly(p-phenylene benzobisthiazole), formed lamellar crystals where the molecular chains were oriented perpendicular to the lamellae. It was supposed that, because of wide distribution in the chain length, the lamellar surface bristled with the chain cilia among which many voids were included. Crystallographically, this region afforded us a transitional structure from full to deficient packings of chains. The structure was analyzed using the scanning probe microscope. In the course the method for imaging one molecular chain end was developed. From the images it was concluded that an isolated long cilius did not move so violently at room temperature. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 35 |
| End Page | 40 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307784 |
| JaLCDOI | 10.18926/15354 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_34_1.pdf |
| Author | Song Baoyin| Inaba, Hideo| Horibe, Akihiko| Takahashi Takashi| |
| Abstract | The experiment for investigating the falling snow melting characteristics of warm water flowing along sheet channels spread on a roof was performed in Tookamachi city, Nigata prefecture from February 6 to February 7, 1995. The sheet surface temperatures at 11 positions in 3 channels were measured. A physical model for a gas-water-snow system was constructed to compare the predicted results with the measured ones. A fully spread uniform water film in the sheet channel was observed in the experiments. The experimental results elucidated that it was feasible to use warm water flowing along sheet channels for melting falling snow on roofs. The temperature drop in the sheet channel mainly depended on the snowfall intensity, atmospheric temperature and wind speed. Under the influence of the roof edge, the temperature drop in the channel next to the side edge was much larger than that in middle channels. A water-snow two phase flow or a snow covered frozen water was experienced temporarily in the lower reaches of the water flowing channel. These suggest that a larger water flow rate is needed for the channel next to the roof edge, and a higher inlet temperature or a greater water flow rate is required for a severe weather condition. There was reasonably good agreement between the measured and predicted water temperatures. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2000-03-27 |
| Volume | volume34 |
| Issue | issue1-2 |
| Start Page | 1 |
| End Page | 12 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307686 |
| JaLCDOI | 10.18926/15356 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_34_13.pdf |
| Author | Sakakibara, Akira| Tanimoto, Tadashi| Matsushima, Takahisa| Hosokawa, Norio| Kanadani, Teruto| |
| Abstract | Repeated tensile fatigue strength of the low temperature age-hardened Al-Zn alloys is investigated varying the specimen thickness. Fatigue strength of the age-hardened specimens decreases with the specimen thickness when the specimen is thinner than a certain thickness, whereas fatigue strength of non age-hardened specimens, i.e., pure aluminum and dilute Al-Zn alloy, does not depend the specimen thickness. The dependence of fatigue strength on the thickness of age-hardened specimen is considered to be caused by the decrease of the strength of specimen as a whole, as a result of increase in volume ratio of the soft surface layer formed after age-hardening with decreasing specimen thickness. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2000-03-27 |
| Volume | volume34 |
| Issue | issue1-2 |
| Start Page | 13 |
| End Page | 17 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307815 |
| JaLCDOI | 10.18926/15357 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_53.pdf |
| Author | Kim Tae Yong| Kagawa, Yukio| |
| Abstract | Fresnel zone plate lens (FZPL) has widely been used in electromagnetic antenna applications. Most analysis method based on the potential (scalar) wave approximation has been applied to a few very limited and simplified cases. The present paper analyzes the FZPL in more general form including the diffraction and transmission using the method of moments (MoM). The focusing gain characteristics in the oblique incidence as well as in the normal incidence are considered. The MoM solution using the three-dimensional vectorial formulation requires a large memory space for the FZPL as it is operated at a short wavelength. This is simply overcome by using an iterative conjugate gradient method for the numerical evaluation. The MoM solutions are compared with the other solutions. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 53 |
| End Page | 61 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307849 |
| JaLCDOI | 10.18926/15358 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_63.pdf |
| Author | Shinomiya Shigeru| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| Abstract | We present a theoretical study of Si(1-x)Ge(x) alloys based on tight-binding molecular dynamics (TBMD) calculations. First, we introduce a new set of nonorthogonal tight-binding parameters for silicon and germanium based on the previous work by Menon and Subbaswamy [Phys. Rev. B 55, 9231 (1997); J. Phys: Condens. Matter 10, 10991 (1998)]. We then apply the method to structural analyses of Si(1-x)Ge(x) alloys. The equilibrium volume and atomic structure for a given x are obtained by the TBMD method. We also calculate the bulk modulus B, elastic constants C(11), C(12) and C(44) as a function of x. The results show that the moduli vary monotonically, but nonlinearly, between the values of Si crystal and Ge crystal. The validity of the results is also discussed. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 63 |
| End Page | 75 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307673 |
| JaLCDOI | 10.18926/15359 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_34_19.pdf |
| Author | Okada, Akira| Uno, Yoshiyuki| Okajima, Isao| |
| Abstract | In EDM, the machining characteristics greatly depend on the energy distribution. Therefore, it is very important to clarify the energy distribution for understanding various phenomena in EDM. In this paper, the energy distribution in EDM with graphite electrode is investigated by measuring the temperatures of electrode and workpiece. Experimental analysis shows that the material removal rate depends on energy density while the electrode wear greatly depends on the adhesion of heat resolved carbon from machining fluid, and the energies distributed into electrode and workpiece are almost constant regardless of pulse duration. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2000-03-27 |
| Volume | volume34 |
| Issue | issue1-2 |
| Start Page | 19 |
| End Page | 26 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307707 |
| JaLCDOI | 10.18926/15360 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_34_27.pdf |
| Author | Wei, He| Koga, Ryuji| Iokibe, Kengo| Wada, Osami| Toyota, Yoshitaka| |
| Abstract | 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. |
| Keywords | Mie lidar Asian dust (KOSA) depolarization ratio backscattering ratio range normalized |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2000-03-27 |
| Volume | volume34 |
| Issue | issue1-2 |
| Start Page | 27 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307539 |
| JaLCDOI | 10.18926/15361 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_77.pdf |
| Author | Kishimoto Tokunari| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| Abstract | In order to perform the large-scale molecular dynamics simulation of the Yukawa system, a mathematical expression for molecular dynamics using the fast multipole method is described. The model simulations are also performed to test the performance of our implementation of the FMM. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 77 |
| End Page | 95 |
| ISSN | 0475-0071 |
| language | English |
| File Version | publisher |
| NAID | 120002307940 |
