Fukui University of Technology

Fukui, Japan

The Fukui University of Technology is a private university founded in 1950 and located in Fukui city, Fukui Prefecture, Japan. Wikipedia.

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Nobukawa S.,Fukui University of Technology | Nishimura H.,University of Hyogo
Neural Computation | Year: 2016

It is well known that cerebellar motor control is fine-tuned by the learning process adjusted according to rich error signals from inferior olive (IO) neurons. Schweighofer and colleagues proposed that these signals can be produced by chaotic irregular firing in the IO neuron assembly; such chaotic resonance (CR) was replicated in their computer demonstration of a Hodgkin-Huxley (HH)-type compartment model. In this study, we examined the response of CR to a periodic signal in the IO neuron assembly comprising the Llinás approach IO neuron model. This system involves empirically observed dynamics of the IO membrane potential and is simpler than the HH-type compartment model. We then clarified its dependence on electrical coupling strength, input signal strength, and frequency. Furthermore, we compared the physiological validity for IO neurons such as low firing rate and sustaining subthreshold oscillation between CR and conventional stochastic resonance (SR) and examined the consistency with asynchronous firings indicated by the previous model-based studies in the cerebellar learning process. In addition, the signal response of CR and SR was investigated in a large neuron assembly. As the result, we confirmed that CR was consistent with the above IO neuron's characteristics, but it was not as easy for SR. © 2016 Massachusetts Institute of Technology.

Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Advances in Polymer Science | Year: 2010

Polymeric features of lignin and its potential as a bio-resource are reviewed, focusing on its characteristic structure and properties. Lignin is a random copolymer consisting of phenylpropane units having characteristic side chains. Lignin slightly crosslinks and takes an amorphous structure in the solid state. The molecular motion is observed as glass transition by thermal, viscoelastic and spectroscopic measurements. The hydroxyl group of lignin plays a crucial role in interaction with water. By chemical and thermal decomposition, a wide range of chemicals can be obtained from lignin that can be used as starting materials for synthetic polymers, such as polyesters, polyethers, and polystyrene derivatives. At the same time, a variety of polymers can be derived from lignin by simple chemical modification. The hydroxyl group acts as a reaction site for the above chemical reaction. © Springer-Verlag Berlin Heidelberg 2009.

Takaki T.,Kyoto Institute of Technology | Tomita Y.,Fukui University of Technology
International Journal of Mechanical Sciences | Year: 2010

We have developed a numerical model of recrystallization taking the inhomogeneities of the plastic deformation of a polycrystalline metal into account. Here, the plastic deformation of the polycrystalline metal is simulated by the finite element method based on crystal plasticity theory and the microstructure evolution during recrystallization is simulated by the multi-phase-field method. In primary recrystallization simulations, nucleation is the most difficult problem. In the present model, the deformation microstructure is predicted from the results of a crystal plasticity finite element simulation, and spontaneous nucleation is achieved through abnormal grain growth that is enabled by introducing the misorientation dependences of grain boundary energy and mobility. As a result of simulations under three different compression strains, it is confirmed that primary recrystallization simulations depending on the amount of deformation and taking the inhomogeneities of the plastic deformation of a polycrystalline metal into consideration can be successfully performed by employing the proposed model. © 2009 Elsevier Ltd. All rights reserved.

Hioki Z.,Tokushima University | Ohkuma K.,Fukui University of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

Constraints on the nonstandard top-gluon couplings composed of the chromomagnetic- and chromoelectric-dipole moments of the top quark are updated by combining the latest data of top-pair productions from the Tevatron, 7-TeV LHC, and 8-TeV LHC. We find that adding the recent 8-TeV data to the analysis is effective to get a stronger constraint on the chromoelectric-dipole moment than the one from the Tevatron and 7-TeV LHC alone. We also discuss how those constraints on the nonstandard couplings could be further improved when the 14-TeV LHC results become available in the near future. © 2013 American Physical Society.

Hioki Z.,Tokushima University | Ohkuma K.,Fukui University of Technology
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Possible non-standard top-quark interactions with the gluon and the W boson induced by SU(3) × SU(2) × U(1) gauge-invariant dimension-6 effective operators are studied for hadron-collider experiments. Current limits on top-gluon couplings are presented by using the latest experimental data of tt productions at the Tevatron and the Large Hadron Collider (LHC). The optimal-observable procedure is applied to the charged-lepton distributions in pp→ttX→ℓ+X' (ℓ = e or μ) at the LHC in order to estimate the expected statistical uncertainties in measurements of those non-standard top-gluon and top-. W couplings that contribute to this process in the leading order. © 2012 Elsevier B.V.

Hioki Z.,Tokushima University | Ohkuma K.,Fukui University of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We study momentum distributions of the final-state charged lepton in pp̄/pp→tt̄→ℓ+X(ℓ=eorμ) at hadron colliders, i.e., Tevatron and Large Hadron Collider (LHC), in order to explore possible new-physics effects in the top-quark sector. Assuming general model-independent tt̄g+tt̄gg and tbW interactions beyond the standard model, we first derive analytical formulas for the corresponding parton-parton processes. We then compute the lepton angular, energy, and transverse-momentum distributions in pp̄/pp collisions to clarify how they are affected by those anomalous couplings. © 2011 American Physical Society.

Shiotsuki M.,Kyoto University | Sanda F.,Kyoto University | Masuda T.,Fukui University of Technology
Polymer Chemistry | Year: 2011

Progress in the polymerization of substituted acetylenes and the properties and functions of the formed polymers that have been synthesized in the past several years are surveyed. Polymerization catalysts for substituted acetylenes, new monomers and polymers, controlled polymerizations, and photoelectronic functions and separation membranes of substituted polyacetylenes are discussed. A focus is placed on the development of novel rhodium catalysts for the polymerization of phenylacetylenes, the helical structures of the polymers obtained from chiral monosubstituted acetylenes, and highly gas-permeable polymers prepared from disubstituted acetylenes, in which great advances have been made recently. © The Royal Society of Chemistry 2011.

Nishiyama E.,Fukui University of Technology | Murahashi T.,Fukui University of Technology
Journal of Power Sources | Year: 2011

Water transport through the gas diffusion media of a proton exchange membrane fuel cell (PEMFC) was investigated with a focus on the role of the microporous layer (MPL) coated on the cathode gas diffusion layer (GDL). The capillary pressure of the MPL and GDL, which plays a significant role in water transport, is derived as a function of liquid saturation using a pore size distribution (PSD) model. PSD functions are derived with parameters that are determined by fitting to the measured total PSD data. Computed relations between capillary pressure and liquid saturation for a GDL and a double-layered GDL (GDL + MPL) show good agreement with the experimental data and proposed empirical functions. To investigate the role of the MPL, the relationship between the water withdrawal pressure and liquid saturation are derived for a double-layered GDL. Water transport rates and cell voltages were obtained for various feed gas humidity using a two-dimensional cell model, and are compared with the experimental results. The calculated results for the net drag with application of the capillary pressure derived from the PSD model show good agreement with the experimental values. Furthermore, the results show that the effect of the MPL on the cell output voltage is significant in the range of high humidity operation. © 2010 Elsevier B.V.

Shikama T.,Fukui University of Technology
2010 IEEE Globecom Workshops, GC'10 | Year: 2010

This paper investigates a TCP proxy that splits a TCP connection into two parts consisting of a wireless link and a wired network. The TCP proxy is effective for improving TCP performance in such a heterogeneous network including a wireless link, on which transmission errors occur. This paper describes how the TCP proxy produces large size forward data due to a packet loss on the wireless link. It also identifies a new problem that the output traffic from the TCP proxy becomes bursty due to the large size forward data. To mitigate bursts of packets by the TCP proxy this paper proposes a scheme that the proxy performs a pacing function which places a gap between two consecutive packets. Since this function is performed in cooperation with the flow control between two TCP connections, the scheme has an advantage that it requires a small amount of forwarding buffers for the pacing. Simulation results using ns-2 show that bursty packets are produced by the conventional TCP proxy and the pacing function suppresses them. The results also show that throughput is improved by the proposed scheme, while the throughput of the conventional TCP proxy suffers from packet losses in the wired network due to the bursts of packets. ©2010 IEEE.

Aoyama T.,Fukui University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

The 2011 off the Pacific coast of Tohoku earthquake (Mw = 9) was one of the most devastating earthquakes in Japanese history. The extremely large and widespread tsunami it generated caused a large amount of debris to flow into the Pacific Ocean. It is important to understand debris flow in the ocean for both environmental research and international relations. In this study, tsunami debris was monitored by satellite remote sensing. As a first step, we propose a method for identifying debris floating on turbid sea areas through thin clouds using two-dimensional scatter diagrams for MODIS spectral bands. Characteristic regions in the images are effectively separated by using the scatter diagram to identify six regions (land, coastal areas, debris, cloud, turbid sea, and clear sea). We report initial results of monitoring debris floating in the Pacific Ocean. © 2012 SPIE.

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