Behavior emergence of a virtual creature living in complex environments

This study aimed at establishing a new computer-aided animation method using agent-based and physics modeling-based animation. The specific problem we addressed was to install adaptive behavior in a virtual creature placed in a complex environment, and to create its animated behavior automatically. The virtual creature is regarded as an autonomous agent who has sensors, actuators, and controllers. An artificial neural netword (ANN) and a central pattern generator (CPG) were adopted as the controllers. An optimization algorithm was introduced to train the controllers. Numerical experiments proved that the virtual creature acquires effective motions (walking, swimming) to move toward its destination, and to avoid obstacles and other creatures.     

Noise rejection method for magnetic noise from wire using ICA for magnetocardiogram

In magnetocardiogram (MCG) measurements, magnetic noise from the wire used to suture the sternum after heart surgery becomes a problem. Independent component analysis is an effective method of noise rejection. In this study, MCG measurements were made on a normal subject with the wire attached and without the wire. We performed signal processing by independent component analysis in order to reduce the effect of magnetic noise from the wire. Comparison of the waveforms after this signal processing with waveforms without the wire clearly showed that magnetic noise caused by the wire was reduced. This result clearly shows that independent component analysis is effective for the removal of magnetic noise from the wire. ©2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 7–14, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20589     

High‐precision positioning control for hard disk drives: 1st report: High‐precision simulator using differential iteration method

The paper proposes a high‐precision simulator for the following mode system design in hard disk drives (HDDs). The simulator is composed of two models: one is a precise mechanical plant which includes numerous high‐frequency vibration modes, and the other is a disturbance signal model which is separated into various disturbances. In the proposed approach, a differential iteration method is applied to identify the precise mechanical plant, providing accurate experimental model analyses. The effectiveness of the synthesized simulator was verified by the comparative studies for experiments and numerical simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 54–61, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20457     

FEM-aided identification of gauge factors of unidirectional CFRP through multi-point potential measurements

Carbon fiber reinforced plastic (CFRP) has electrical conductivity in both the parallel and transverse directions of the fiber. Because an electrical network may be changed with the applied strain, the electrical conductivity of the CFRP will also be changed for the piezoresistivity. Strain monitoring of CFRP can therefore be conducted, not by using an additional sensor, but by measuring the change in electrical resistance. There have been many studies on the gauge factors of unidirectional CFRPs, although significant mutual differences have been determined in the results reported. It is thought that the differences may be caused by the strong electrical anisotropy and inhomogeneity of the unidirectional CFRP. In this study, a new concept was introduced to precisely measure the gauge factors of a unidirectional CFRP. A finite element analysis was utilized to take into consideration a non-uniform electrical potential field in a unidirectional CFRP. The gauge factors were obtained as a result of minimizing the error sum of the squares of the electrical potentials between the experimental and analytical results. The gauge factor in the fiber direction was affected by this factor in the thickness direction depending on the specimen configuration. The results of the finite element analysis showed the possibility of a unidirectional CFRP showing both positive and negative gauge factors in the fiber direction.     

In situ pressure calibration for piston cylinder cells via ruby fluorescence with fiber optics

A fiber-optic measurement technique is developed for estimating the pressure inside a piston cylinder cell up to approximately 4 GPa, based on the pressure-induced R1 fluorescence line shift of ruby (ruby scale). Ruby scale and a conventional technique (calibration on phase transitions of bismuth) were simultaneously applied to the cell filled with a pressure transmitting medium of isopropyl alcohol. The pressure readings of the two methods were consistent with each other, and no pressure gradient was observed. The ruby scale has the advantages of real time estimation and easy installation in a small space. Because of these advantages, three fibers were simultaneously introduced in the sample space at the same time, and pressure distribution was measured for Fluorinert (FC70:FC77=1:1), Daphne oil 7373, and Fomblin oil (YHVAC 13014).     

Synthesis and characterization of three-branched star-like poly(γ-benzyl-l-glutamate)

Summary Three branched star-like poly(-benzyl-l-glutamate) was synthesized using three functional amine as an initiator, and characterized through light-scattering, ORD and intrinsic viscosity measurements. Experimental results suggest that the synthesized star-like poly(-benzyl-l-glutamate)s are composed of three branches of equal length.     

Heat transfer and pressure loss characteristics of very compact heat sinks

High-performance compact heat sinks have been developed for the effective cooling of high-density LSI packaging. Heat transfer and pressure loss characteristics of the heat sinks in both air-cross-flow and air-jet cooling have been experimentally studied. The present heat sinks were of plate-fin and pin-fin arrays with a fin pitch of 0.7 mm. The plate-fin heat sinks had higher cooling performance than the pin-fin heat sinks in the range of large airflow rates both in air-cross-flow and air-jet cooling. The thermal conductance in cross-flow cooling was 20 or 40% larger than that in jet cooling. The correlation of Colburn j-factor/Fanning friction factor versus the Reynolds number for the present heat sinks was found to be very close to that of a conventional large-size heat exchanger. © Scripta Technica, Heat Trans Asian Res, 28(8): 687-705, 1999     

Polypropylene-grafted nanoparticles as a promising strategy for boosting physical properties of polypropylene-based nanocomposites

SiO₂ nanoparticles grafted to terminally hydroxylated polypropylene (PP-g-SiO₂) with different molecular weights were melt mixed with PP to prepare a series of PP/PP-g-SiO₂ nanocomposites. PP/PP-g-SiO₂ offered several advantages over pristine PP and PP/unmodified SiO₂ such as highly uniform dispersion up to 10 wt.-%, +200–400% faster crystallization and +30% increments for both the Young's modulus and the tensile strength without largely sacrificing the melt viscosity of PP. We concluded that grafted chains act as crystallization nuclei and co-crystallize with matrix chains to make PP-g-SiO₂ nanoparticles as a physical cross-linker between lamellae, while the linkage disappears in melt and grafted chains minimize the cohesive attraction between nanoparticles.     

Transmission analysis of electromagnetic induction RFID system

The transmission characteristics of the electromagnetic induction RFID systems are greatly influenced by the distance between the primary and secondary antenna coils and by the materials used in their design. In this paper the induced current of the secondary antenna coil is calculated by the 3D finite element method when both the primary and secondary antenna coils are operated in resonant circuits. The influences of the analyzed parameters on the transmission characteristics are demonstrated. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 38–45, 2010; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21019     

An Information-Spectrum Approach to Classical and Quantum Hypothesis Testing for Simple Hypotheses

The information-spectrum analysis made by Han for classical hypothesis testing for simple hypotheses is extended to a unifying framework including both classical and quantum hypothesis testing. The results are also applied to fixed-length source coding when loosening the normalizing condition for probability distributions and for quantum states. We establish general formulas for several quantities relating to the asymptotic optimality of tests/codes in terms of classical and quantum information spectra