Hiroshima, Japan

Hiroshima National College of Maritime Technology is one of five national colleges of maritime technology in Japan. Graduates can earn deck mariner or engineer qualifications. Wikipedia.


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Imai S.,Hiroshima National College of Maritime Technology | Yamamoto T.,Hiroshima University
IEEJ Transactions on Electronics, Information and Systems | Year: 2012

Almost real-world processes are represented as nonlinear systems. Therefore, it is important to consider control schemes to cope with such systems. In this paper, a control method for nonlinear systems is newly proposed. Some local linear models on typical equilibrium points are first designed, followed by linear controllers corresponding to these models. The distances between the query and these local models are calculated, and the weights are computed in proportion to the distances. These weights are put for local controllers, and the controller corresponding to the query can be designed. According to the proposed scheme, the good control performance can be easily obtained. The effectiveness of the proposed control scheme is shown by some simulation examples. © 2012 The Institute of Electrical Engineers of Japan.


Sasa K.,Hiroshima National College of Maritime Technology | Hibino T.,Hiroshima University | Kim K.,Hiroshima University
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2010

The influence of tidal currents is a very important factor in port planning. However, there are still many ports that do not necessarily satisfy this fundamental rule, especially in small ferry berths. This study describes the present situation of Japanese ports under strong tidal currents. First, meteorological and oceanographic parameters have been observed to understand the propert ies of seawater and tidal currents. To evaluate a difficulty of ferry berthing, it is essential to take ship motion into consideration. This new numerical simulator makes it possible to reproduce motions of a berthing ship in tidal currents and winds while applying maneuvering forces. With this system, ship motions can be accurately reproduced, which makes it possible to quantify berthing criteria. © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).


Takiguchi M.,Hiroshima National College of Maritime Technology | Yoshida T.,Hiroshima National College of Maritime Technology | Funaki M.,Hiroshima National College of Maritime Technology | Yoshida F.,Hiroshima University
Key Engineering Materials | Year: 2013

In this paper, the effects of the thicknesses of sheet and adhesive layer on plastic forming of adhesively bonded sheet metals were investigated by experiments and the corresponding numerical simulation. The main conclusions obtained are as follows: (1) When the thickness of the adherends increases, the gull-wing bend of the bent sheet and the transverse shear deformation in the adhesive layer become larger, which in some cases the delamination occurs in the adhesive layer. (2) The gull-wing bend of the bent sheet becomes larger with increasing adhesive layer thickness, but conversely the shear strain in the adhesive layer becomes smaller. © (2013) Trans Tech Publications, Switzerland.


Imai S.,Hiroshima National College of Maritime Technology | Yamamoto T.,Hiroshima University
International Journal of Advanced Mechatronic Systems | Year: 2012

Almost real-world plants are represented by non-linear systems. Therefore, it is important to consider PID control schemes to cope with such systems. In this paper, a PID control method for non-linear systems is newly proposed. Some local linear models on typical equilibrium points are first designed, followed by linear PID controllers corresponding to these models. The distances between the query and these local models are calculated, and the weights are computed in proportion to the distances. These weights are put for local PID controllers, and the PID controller corresponding to the query can be designed. According to the proposed scheme, the good PID control performance can be easily obtained. The effectiveness of the PID control scheme is illustrated by some simulation examples and experiment. © 2012 Inderscience Enterprises Ltd.


Ishihara Y.,Meiji University | Ohwada H.,Hiroshima National College of Maritime Technology
International Journal of Hyperthermia | Year: 2011

Purpose: To improve the efficacy of hyperthermia treatment, a novel method of non-invasive measurement of changes in body temperature is proposed. The proposed method is based on phase changes with temperature in electromagnetic waves in a heating applicator and the temperature dependence of the dielectric constant. An image of the temperature change inside a body is reconstructed by applying a computed tomography algorithm. This method can be combined easily with a heating applicator based on a cavity resonator and can be used to treat cancer effectively while non-invasively monitoring the heating effect. In this paper the phase change distributions of electromagnetic waves with temperature changes are measured experimentally, and the accuracy of reconstruction is discussed. Materials and methods: The phase change distribution is reconstructed by using a prototype system with a rectangular aluminum cavity resonator that can be rotated 360° around an axis of rotation. To make measurements without disturbing the electromagnetic field distribution, an optical electric field sensor is used. The phase change distribution is reconstructed from 4-projection data by using a simple back-projection algorithm. Results: The paper demonstrates that the phase change distribution can be reconstructed. The difference between phase changes obtained experimentally and by numerical analysis is about 20% and is related mainly to the limited signal detection sensitivity of electromagnetic waves. Conclusions: A temperature change inside an object can be reconstructed from the measured phase changes in a cavity resonator. © 2011 Informa UK Ltd All rights reserved.


Imai S.,Hiroshima National College of Maritime Technology | Yamamoto T.,Hiroshima University
IEEE International Conference on Emerging Technologies and Factory Automation, ETFA | Year: 2012

PID Control schemes have been widely used in most process control systems. However, most process systems are nonlinear, it is difficult to obtain good control performances using simple controllers with the fixed PID parameters. This paper describes a design scheme of nonlinear controllers with a local linear models structure. The linear model is designed using the data-driven(DD) approach. The DD approach is effective in describing the nonlinear components. In addition, it is easy to construct the local linear models, if the system model can be suitably designed. According to the proposed control system, the desired control performance can be obtained for nonlinear systems. © 2012 IEEE.


Sasa K.,Hiroshima National College of Maritime Technology | Incecik A.,University of Strathclyde
Ocean Engineering | Year: 2012

It is essential to maintain the safety of ships that are anchored in offshore harbors to avoid the influence of storms. Recently, marine casualties have been reported on anchored ships stranded in coastal areas after their anchors dragged in stormy weather. However, there have been very few studies on anchored ship motions in waves with dynamic mooring forces. In this study, information on the safety of ships in offshore harbors during storms was gathered through a nationwide questionnaire. Because previous numerical models for reproducing reported situations of marine casualties appear flawed, this study considers the dynamic calculation of chain forces and compares the results with those obtained by the catenary method. A new algorithm is constructed to reproduce the dragging anchor and grounding in waves and winds. This study is expected to contribute to the improvement of port planning related to anchorage. © 2012 Elsevier Ltd. All rights reserved.


Sakuma Y.,Hiroshima National College of Maritime Technology | Inoie A.,Kanagawa Institute of Technology
Operations Research Letters | Year: 2012

This paper analyzes a multi-server queueing system with multiple vacations in which the vacation duration of each server is exponentially distributed. When all the servers are on vacation, customers are impatient if their waiting times exceed a constant value. To derive the stationary distribution of the system, we employ the matrix analytic method. Specifically, our queueing model is represented as an MG1-type Markov chain, and the stationary distribution is simply obtained by using its transition structures. Furthermore, we explicitly derive the tail decay rate of the stationary distribution, and demonstrate that the decay rate is not always equal to that for the queueing model without vacations. © 2012 Elsevier B.V. All rights reserved.


Tanaka K.,Yamaguchi University | Mu S.,Hiroshima National College of Maritime Technology | Nakashima S.,Yamaguchi University
International Journal of Automation Technology | Year: 2014

This paper proposes a meal-assistance robot that uses ultrasonic motors (USMs) and an eye-interface. The proposed robot is designed with simple manipulators moving in orthogonal coordinate axes to avoid unsafe motion and vibration. With the application of USMs, the proposed robot has excellent features. In particular, because it does not interfere with other electronic devices, the proposed robot is satisfactory choice for medical and welfare facilities. Moreover, the proposed robot is designed to be controlled with an eyeinterface, which makes this robot much easier to use than previous models. The structure of the robot is introduced and its effectiveness is confirmed by experiments.


Zhou D.,Tokyo University of Marine Science and Technology | Izumi M.,Tokyo University of Marine Science and Technology | Miki M.,Tokyo University of Marine Science and Technology | Felder B.,Tokyo University of Marine Science and Technology | And 2 more authors.
Superconductor Science and Technology | Year: 2012

The paper contains a review of recent advancements in rotating machines with bulk high-temperature superconductors (HTS). The high critical current density of bulk HTS enables us to design rotating machines with a compact configuration in a practical scheme. The development of an axial-gap-type trapped flux synchronous rotating machine together with the systematic research works at the Tokyo University of Marine Science and Technology since 2001 are briefly introduced. Developments in bulk HTS rotating machines in other research groups are also summarized. The key issues of bulk HTS machines, including material progress of bulk HTS, insitu magnetization, and cooling together with AC loss at low-temperature operation are discussed. © 2012 IOP Publishing Ltd.

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