Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 A Group Signature Scheme with Easy Membership Canceling 207 212 EN Toru Nakanishi 10.18926/15382 In the group signature scheme with a trusted party, a verifier can determine whether or not a signature is made by a member of the group, but cannot identify the member who signed the signature. In case of dispute later on, the signer can be identified by the trusted party. However, for efficient group signature schemes proposed so far, removing a member from the group can be not efficiently performed. In this paper, a group signature scheme with an easy membership canceling is proposed. By sending a request to use a resource together with the group signature on it to the manager of the resource, the manager can control anonymous accesses to the resource. In such an application, the proposed group signature scheme is suitable for canceling of the access privilege. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Determining Minimal Polynomial of Proper Element by Using Higher Degree Traces 197 205 EN Yasuyuki Nogami Yoshitaka Morikawa 10.18926/15380 Modern communication engineerings, such as elliptic curve cryptographies, often requires algebra on finite extension field defined by modulus arithmetic with an irreducible polynomial. This paper provides a new method to detemine the minimal (irreducible) polynomial of a given proper element in finite extension field. In the conventional determination method, as we have to solve the simultaneous equations, the computation is very involved. In this paper, the well known "trace" is extended to higher degree traces. Using the new traces, we yield the coefficient formula of the desired minimal polynomial. The new method becomes very simple without solving the simultaneous equations, and about twice faster than the conventional method in computation speed. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Disassembly System using an Impact Hammer for the Material Recycling 191 196 EN Yoshiomi Munesawa Hirokazu Osaki Yasuhiro Kajihara 10.18926/15378 We developed the disassembly system that uses the impulsive load and disassembly tools to disassemble used appliances economically. The main components of this system are impulse hammer, a lift table and developed disassembly tools. Several types of disassembly tools are developed to punch out fastened portion on a part and cut off the shaft of screw or connection pin of IC-chip. A simulation model is proposed to explain and formulate how the fastening point of product is broken and cut. Three kinds of disassembly tools are designed. The actual disassembly system is developed by using proposed simulation models and disassembly tools. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 A Method for Design Production System with Multi Energy Resources 183 189 EN Hirokazu Osaki Yasuhiro Kajihara Yoshiomi Munesawa 10.18926/15376 This research proposes a strategy for reducing both electricity charge and environmental load by considering multi energy sources. The reduction of the contract electric demand is considered, and its differential cost is used for purchasing substitute power sources. Some variables, such as the amount of reduced contract demand, and amount of electricity are generated by each substitute power source. By using those variables, we formulate a simulation model that enables to minimize the energy cost and environmental cost. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Cooperative Handling Robot with Human Beings 177 182 EN Hirokazu Osaki Yasuhiro Kajihara Yoshiomi Munesawa 10.18926/15375 The focus of this paper is on the analysis of delivery motion of human, development of an image processing method based on the motion analysis and development of the cooperative delivery robot using the image processing method. The proposed image processing method uses two cameras, and it uses a stereo reconstruction technique for measuring position and postures of hands. In addition, this image processing method recognize the number of fingers extending consciously, so the cooperative human beings could choose the kind of tool which he wants by holding out his hand in front of cameras. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 An Image Processing Method for Handling Subject Piled in a Container 169 175 EN Hirokazu Osaki Yasuhiro Kajihara Yoshiomi Munesawa 10.18926/15373 We propose an image processing method for part handling robot for picking up subjects piled in a container. Line laser light is projected on subjects, and its external shape is detected by many segments of a line laser, and pitch, roll, and yaw angles of subject are recognized precisely. A priority rule is settled to choose one subject that is taken out. This rule is determined by considering the grasping space, the position of a subject, the movement space of hand and so on. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Development of Assembly Robot System for Flexible Belt-Shaped Subject 163 168 EN Hirokazu Osaki Yasuhiro Kajihara Yoshiomi Munesawa 10.18926/15371 We develop an assembly robot system for assembling the flexible belt-shaped subject. An image processing method is developed to recognize the belt-shaped subject. This method is able to determine the grasping point and grasping angle for piking up a subject by a multiple hands unit. CAD information is used to determine the grasping point. The multiple hands unit is developed, which is able to grasp all grasping points of a subject at a time. In addition, the image processing method is used to judge whether a subject is fastened accurately at right position or not during the assembly. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Methods for Tele-Operation of Mobile Type Maintenance Robot 155 161 EN Yoshiomi Munesawa Yasuhiro Kajihara Hirokazu Osaki 10.18926/15368 This paper proposes a concept of a mobile type maintenance robot (MMR in shortly) that is controlled by the tele-operation for assuring the safety and health improvement of work forces. The main components of this system are the industrial robot, an image processing unit, vehicle and computers for tele-operation. Our focus is paid on a method that determine a pathway to move every places where troubles would occur. This method makes it possible that the MMR could arrive any place in the factory with three times of turns at most. Additionally, turning radius of the vehicle is considered for correcting the pathway near the corners to make it possible that it arrives to the place accurately. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 The role of interhelical cleavage for insecticidal activityof Bacillus thuringiensis Cry4A toxin 147 154 EN Masashi Yamagiwa Hiroshi Sakai 10.18926/15366 The Cry4A toxin is a dipteran-specific insecticidal protein produced by Bacillus thuringiensis subsp. israelensis as a protoxin of 130 kDa. Its active form is a heterodimer of 20- and 45-kDa fragments which is generated by an interhelical cleavage of a 60-kDa intermediate at the position of Gln236 between α5 and α6 helices in domain I. On the other hand, Cry1Aa, which is also produced as a 130-kDa protoxin but toxic to lepidopteran larvae, was processed into the active 60-kDa fragment with no additional cleavage. To investigate the role of the intramolecular cleavage of Cry4A for its insecticidal activity, the loop between α5 and α6 of Cry4A which includes the cleavage site was substituted for the corresponding region of Cry1Aa. The resulting mutant designated GST-60Loop was expressed as a GST-fusion protein. A difference of the processing profile was observed between GST-60 and GST-60Loop in the in vitro digestion assay by trypsin, and the insecticidal activity of GST-60Loop was two-fold lower than that of GST-60. These results suggested that the interhelical cleavage of Cry4A promoted the toxicity against C. pipiens larvae. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Characteristics of a Monoacylglycerol Lipase Isolated from Pseudomonas sp. LP7315 -Hydrolysis and Synthesis of Monoglycerides 137 146 EN Takaharu Sakiyama Tsuyoshi Yoshimi Akira Miyake Midori Umeoka Atsushi Tanaka Sho Ozaki Kazuhiro Nakanishi 10.18926/15364 A monoacylglycerol lipase (MGL) was purified from Pseudomonas sp. LP7315 by ammonium sulfate precipitation, anion-exchange chromatography, and preparative electrophoresis. The purified enzyme was homogeneous on an SDS-polyacrylamide gel with a molecular mass of 59 kDa. Its hydrolytic activity was confirmed to be specific for monoglycerides: the enzyme did not hydrolyze diand triglycerides. MGL was found to be stable even after l-h incubation at 65℃. The hydrolytic activity depended not only on temperature and pH but also on the type of monoglyceride used. MGL also catalyzed monoglyceride synthesis at 65℃ in a solvent-free two-phase system, in which fatty acid droplets were dispersed in the glycerol phase with a low water content. The synthetic reaction proceeded at a constant rate for approximately 24 h and reached an equilibrium after 48 h of reaction. The initial rate of the synthetic reaction depended on several factors: the type of fatty acid used as the substrate, the amounts of fatty acid and glycerol, and the concentration of MGL in the glycerol phase. To analyze the effects of these factors, a kinetic model was developed based on the assumption that the adsorption equilibrium of MGL molecules at the interface between the two phases is the rate-determining factor for the synthetic reaction. The model was found to yield a good approximation of the initial synthetic rate under various reaction conditions. The analysis suggests that the adsorption behavior of MGL onto the interface had a large effect on the initial rate of the monoglyceride synthesis. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Abductive Proof Procedure with Adjusting Derivations for General Logic Programs 97 135 EN Susumu Yamasaki Yoshinori Kurose 10.18926/15362 In this paper, we formulate a new integrity constraint in correlation with 3-valued stable models in an abduction framework based on general logic programs. Under the constraint, not every ground atom or its negation is a logical consequence of the theory and an expected abductive explanation, but some atom may be unspecified as a logical consequence by an adjustment. As a reflection of the integrity constraint with an adjustment, we augment an adjusting derivation to Eshghi and Kowalski abductive proof procedure, in which such an unspecified atom can be dealt with. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Molecular Dynamics of Yukawa System using the Fast Multipole Method 77 95 EN Chieko Totsuji Kenji Tsuruta Hiroo Totsuji 10.18926/15361 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Nonorthogonal Tight-Binding Molecular Dynamics for Si(1-x)Ge(x) Alloys 63 75 EN Chieko Totsuji Kenji Tsuruta Hiroo Totsuji 10.18926/15358 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Focusing Characteristic Analysis of Circular Fresnel Zone Plate Lens 53 61 EN Yukio Kagawa 10.18926/15357 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Scanning Probe Microscopy of Poly(p-phenylene benzobisthiazole) Lamellar Crystal 35 40 EN Kaoru Shimamura Tetsuya Uchida Tomohiro Inoue 10.18926/15352 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Synthesis of Poly(ethylene-block-vinylalcohol)for Use as Amphiphilic Film Surface at High Temperature 29 34 EN Kaoru Shimamura Tetsuya Uchida 10.18926/15350 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Laser Welding of Slices of Magnetic Circuit 21 28 EN Volodymyr S.kovalenko Yoshiyuki Uno Yasuhiro Okamoto M. Anyakin A. Lutay Khaled Al. Shubul 10.18926/15348 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Ultra-Micro Hardness Testing and Microscopic Deformationof Polycrystalline Aluminum 9 19 EN Takeji Abe Tomoaki Tsuboi 10.18926/15346 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Microscopic Observation of Plastic Deformation of Polycrystalline Aluminum by Laser Scanning Microscope 1 8 EN Takeji Abe Ichiro Shimizu 10.18926/15344 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Diagnostic method for induction motor using simplified motor simulator 47 51 EN Yukihiro Doumae Masami Konishi Jun Imai Hideki Asada Akira Kitamura 10.18926/15269 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. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 35 1-2 2001 Alkenylation and Allylation of Aldehydes by Using an Ni/Cr/TDAE Redox System 41 46 EN Manabu Kuroboshi Muneaki Tanaka Suguru Kishimoto Kentaro Goto Hideo Tanaka 10.18926/15164 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. No potential conflict of interest relevant to this article was reported.