Maizuru National College of Technology

Kyoto, Japan

Maizuru National College of Technology

Kyoto, Japan
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Miwa H.,Maizuru National College of Technology | Parker G.,University of Illinois at Urbana - Champaign
Earth Surface Processes and Landforms | Year: 2017

When fine sediments are present in gravel streambeds (gravel-framework beds), the gravel can be more easily removed from its original position, compared with gravel in a streambed without fine sediment but otherwise under the same hydraulic conditions. In this study, the effect of the presence of sand on the initiation of gravel motion in gravel riverbeds was investigated using flume experiments. The relationship between the critical Shields stress for gravel motion initiation and the fraction of sand in the bed was determined experimentally. The results can be summarized as follows. (1) When the fraction of sand in the bed is smaller than about 0.4, the critical Shields stress for the initiation of gravel motion decreases with increasing fraction of sand. The critical Shields stress increases, however, with increasing fraction of sand when it is larger than about 0.4. (2) The difference between the value of the critical Shields stress predicted by the Egiazaroff equation and the value obtained from the experimental data becomes maximum at about 0.4 of the fraction of sand. Here an empirical relation between the critical Shields stress and the fraction of sand is proposed so as to consider the effects of the ratio of the characteristic gravel size to the mean size of the bed material on the critical Shields stress. (3) Gravel in armored beds can be more easily mobilized by supplying sand as part of a sediment augmentation scheme. The sand fraction in the subsurface layer of the bed appears to reduce the friction angle of exposed particles. Sediment augmentation using sand has been recently demonstrated to be a viable alternative for mobilizing gravel for the restoration of gravel-bed rivers downstream of dams. The quantitative evaluation obtained through the experiments reported here may be useful for the design of augmentation schemes. © 2017 John Wiley & Sons, Ltd.


Hanaoka T.,Japan National Institute of Advanced Industrial Science and Technology | Sakanishi K.,Japan National Institute of Advanced Industrial Science and Technology | Okumura Y.,Maizuru National College of Technology
Fuel Processing Technology | Year: 2012

The CO 2 gasification behavior of biomass chars derived at 800 °C under N 2/CO 2/O 2 atmospheres (N 2: 17-100%, CO 2: 0-83%, O 2: 0-42%) and at 0.02 kPa and 1.0 MPa was investigated using the random pore model (RPM) at gasification temperatures of 800-1000 °C. The CO 2 gasification rate constants (K p) of chars derived at 0.02 kPa increased with the Brunauer-Emmett-Teller (BET) specific surface area up to 417 m 2 g - 1 and were 1.5-3.2 times those derived at 1.0 MPa. In particular, K p for the char derived at 0.02 kPa and N 2/CO 2/O 2 = 18/41/41 vol.% exhibited the maximum values and K p (0.3 min - 1) at 900 °C for the char was 1.7-2.5 times that of chars under other conditions. K p at a given gasification temperature for chars derived at 1.0 MPa was almost independent of N 2/CO 2/O 2 contents. Chars derived at 0.02 kPa had more amorphous structures and much higher BET specific surface areas (189-417 m 2 g - 1) and pore diameters (0.10-0.24 cm 3 g - 1) with an average pore of 2.2-2.4 nm. The char derived under N 2/CO 2/O 2 = 18/41/41 vol.% had a BET specific surface area of 417 m 2 g - 1 and a pore volume of 0.24 cm 3 g - 1, and an average pore diameter of 2.3 nm. Those derived at 1.0 MPa had BET specific surface areas, pore volumes and average pore diameters of 2.1-4.3 m 2 g - 1, 0.01-0.02 cm 3 g - 1, and 15.9-22.8 nm, respectively, and these properties were almost independent of N 2/CO 2/O 2 contents. © 2012 Elsevier B.V.


Kanamori M.,Maizuru National College of Technology
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2014

The present paper describes finite-gain L2 stability guaranteed locally by the proposed anti-windup adaptive law for Euler-Lagrange systems with actuator saturation. All constant parameters of the robot system are estimated for an arbitrary target orbit. In order to achieve finite-gain L2 stability and ensure adaptive tracking performance, an output saturation function of the tracking error is introduced. The finite L2 gains are derived considering four actuator saturation cases, and finite-gain L2 stability is guaranteed locally based on passivity. The control performance is verified through numerical simulations using a two-link robot arm. © 2014 IEEE.


Shin-Ike K.,Maizuru National College of Technology
Proceedings of the SICE Annual Conference | Year: 2010

In general the number of neurons in the hidden layer of multi-layer neural network is determined by trial and error of researchers. There is also an information criteria to determine the number of neurons in the hidden layer. In this paper, we propose a two-phase method to determine the optimal number of neurons in the hidden layer of a 3-layer neural network. In the first phase, candidates of the number of neurons in the hidden layer are determined by using the back-propagation method. In the second phase, the optimal number of neurons is determined by considering the generalization capacity. It is found from the prediction results that the two phase method for determining the number of neurons in the hidden layer is superior to the decision method of trial and error of researchers. In addition, since the number of neurons in the hidden layer can be determined in a short time, it is thought that the proposed method is effective. © 2010 SICE.


Takatani T.,Maizuru National College of Technology
WCTE 2014 - World Conference on Timber Engineering, Proceedings | Year: 2014

3-D non-linear collapsing process analysis of an old two-story wooden house, "Kyo-machiya" structure, was conducted against a strong earthquake ground motion with the Japan Meteorological Agency (JMA) seismic intensity of "6 upper" level, in order to investigate the seismic behaviour of Kyo-machoya structure built by a Japanese traditional framedconstruction method. A non-linear behaviour of timber elements in the wooden house during a strong earthquake ground motion can be simulated by this collapsing analysis. As a result, seismic response of the wooden house depends on the seismic intensity of the input earthquake motion in the collapsing analysis. Also, there seems to be a possibility that the old two-story wooden house may be collapsed by a strong earthquake motion with the seismic intensity of "6 upper" level.


Tokunaga Y.,Maizuru National College of Technology
Proceedings of Meetings on Acoustics | Year: 2013

When hearing music in an auditorium, audience is provided with aural information and visual information at the same time. Visual and auditory sense sometimes interact with each other so that the auditory sense is considered to have some influence on sound evaluation made by audience. The purpose of this study is to reveal an influence of visual information obtained in audience seats in a hall on subjective evaluation. We investigated the relationship between sound evaluation and whether a musical performance video as visual stimulus is provided or not, and between the sound evaluation and evaluation concerning the space at certain position in the audience seats. As a result, it was revealed that visual information gave statistically significant influence on sound evaluation. © 2013 Acoustical Society of America.


Kanamori M.,Maizuru National College of Technology
IEEE International Conference on Automation Science and Engineering | Year: 2011

Using an output saturation function of the error vector (difference between the target vector and the revolution angle vector), globally asymptotic stability of any equilibrium state can be achieved for an anti-windup PID position control of Euler-Lagrange systems with actuator saturation. The control performance is verified by numerical simulations and experiments on a two-link robot arm. © 2011 IEEE.


Kanamori M.,Maizuru National College of Technology
Proceedings of 2013 3rd International Conference on Instrumentation, Control and Automation, ICA 2013 | Year: 2013

The present paper proposes an anti-windup adaptive law for Euler-Lagrange systems with actuator saturation. For an arbitrary target orbit, all constant parameters of the robot system are estimated by the proposed anti-windup adaptive law. In order to ensure tracking performance with actuator saturation, the input saturation state is classified into four saturation cases, and an adaptive law is given for each case. Switching of the adaptive law according to saturation case is proposed. Two Lyapunov functions, such as hybrid control, are derived and global asymptotic stability is ensured by energy dissipation between the two Lyapunov functions. The control performance is verified through numerical simulations using a two-link robot arm. © 2013 IEEE.


Kanamori M.,Maizuru National College of Technology
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2012

Finite-gain L2 stabilization is achieved locally for a system using a PID set position controller and a newly proposed static anti-windup compensation for Euler-Lagrange systems with actuator saturation and external disturbances. In a closed-loop nonlinear system with feedback and input saturation, L2 stability of the Euler-Lagrange systems is guaranteed based on the passivity of anti-windup compensation. The control performance to counter an external disturbance added for the purpose of input saturation is verified by numerical simulations and experiments using a two-link robot arm. © 2012 IFAC.


Kanamori M.,Maizuru National College of Technology
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2012

This paper proposes an anti-windup adaptive law for Euler-Lagrange systems with actuator saturation. The target posture is set to be constant and the asymptotic input is compensated by adaptive estimation of parameters of the gravity term. In order to achieve global asymptotic stability and to assure adaptive control performance, an output saturation function of the error vector between the rotation and target angles is introduced on the basis of quasi-natural potential. According to the saturation state, switching of the adaptive law is proposed to achieve asymptotic stability based on the Lyapunov theorem. The control performance is verified by numerical simulations and experiments on a two-link robot arm. © 2012 IFAC.

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