Mean Field Analysis of Stochastic Neural Network Models with Synaptic Depression

We investigated the effects of synaptic depression on the macroscopic behavior of stochastic neural networks. Dynamical mean field equations were derived for such networks by taking the average of two stochastic variables: a firing state variable and a synaptic variable. In these equations, their average product is decoupled as the product of averaged them because the two stochastic variables are independent. We proved the independence of these two stochastic variables assuming that the synaptic weight is of the order of 1/N with respect to the number of neurons N. Using these equations, we derived macroscopic steady state equations for a network with uniform connections and a ring attractor network with Mexican hat type connectivity and investigated the stability of the steady state solutions. An oscillatory uniform state was observed in the network with uniform connections due to a Hopf instability. With the ring network, high-frequency perturbations were shown not to affect system stability. Two mechanisms destabilize the inhomogeneous steady state, leading two oscillatory states. A Turing instability leads to a rotating bump state, while a Hopf instability leads to an oscillatory bump state, which was previous unreported. Various oscillatory states take place in a network with synaptic depression depending on the strength of the interneuron connections.Comment: 26 pages, 13 figures. Preliminary results for the present work have been published elsewhere (Y Igarashi et al., 2009. http://www.iop.org/EJ/abstract/1742-6596/197/1/012018

Non-contingent reinforcement as a treatment for problem behaviors in the natural contexts of a special needs school.

This study evaluate the effects of an intervention package, including non-contingent reinforcement(NCR), to reduce severe problem behaviors of a student with autism and mental retardation in the daily program of a special needs school. Prioritizing the practicality of assessment and intervention procedures, we relied on interview and direct observation to identify the function of the problem behaviors and selected a maintained reinforcer that was easily delivered among alternatives. In Intervention 1, NCR was provided, with extinction (EXT) and contingent response to communicative behaviors(CR). In Intervention 2, visual schedule and peer mediated strategy, in addition to NCR, EXT, and CR, were introduced. Reduction of the problem behaviors occured following Intervention 1, and more substantial occurred following Intervention 2. Additionally, increases in class participation were noticeable after Intervention 2. Additionally, increases in class participation were noticeable after Intervention 2 was implemented. On the basis of these results, we discussed practical ways of implementing NCR interventions in school settings where controlling environments is typically difficult

The development of “Ultimate Rudder” for EEDI

EEDI (Energy Efficiency Design Index) came into effect mandatory in Jan. 2013, and the ship owners definitely required a higher efficiency propulsion system than ever before. Hence, the shipyards have been conducting an optimization of ESD (Energy Saving Device) system in self-propulsion test for each project. As the results, the shipyards have installed a rudder bulb as an effective ESD. The rudder bulb is a popular ESD system from a long time ago. Mewis1) described that the rudder bulb was developed by Costa in 1952 and the efficiency improve by the rudder bulb for a container vessel was 1% on average. Fujii et al.2) developed “MIPB (Mitsui Integrated Propeller Boss)” as an advanced rudder bulb. The feature of MIPB was a streamlined profile from propeller cap to rudder. According to their paper, the efficiency improve by installing MIPB was 2-4%. Recently, NAKASHIMA PROPELLER Co., Ltd. developed ECO-Cap (economical propeller cap)3) as a new ESD with FRP (Fiber Reinforced Plastics). The strength of FRP is higher than that of NAB (Nickel Aluminium Bronze), therefore ECO-Cap was able to adopt thin fins on propeller caps for low resistance. Although the material used for the energy- saving propeller cap was generally NAB, the research results on FRP showed that FRP could be used as ESD due to their properties such as lightweight and flexibility. As explained above, the authors thought that there was a possibility to evolve the rudder bulb profile using the easily moldable FRP compared with NAB. This paper described about the development of “Ultimate Rudder” of new design concept by FRP. The authors optimized the profile of “Ultimate Rudder” by CFD and confirmed the efficiency increase from 4.9 to 5.4% in self-propulsion test

Study on the rudder characteristics of ultimate rudder by numerical calculation

The authors invented Ultimate Rudder3) as the rudder with bulb. The authors calculated the rudder characteristics of the normal rudder and Ultimate Rudder by CFD at several steering angles and compared these values. The result showed that regardless of the presence or absence of the bulb, signs of separation appear on the control surface with a steering angle of 20 deg. to 30 deg. and regarding the steering torque coefficient, it was found that the steering torque coefficient of Ultimate Rudder is larger than the normal Rudder when the steering angle is less than 20 deg. and also the steering torque coefficient can be decreased by changing the shape of the rudder bulb

Systematic Improvement of Teaching to Realize the School’s Educational Goals -Japanese Language Instruction as the core of the Program-

　本研究の目的は、「目指す生徒像」を意識した学校の組織改善の具体を報告し、そのあり方を提言することにある。いつの時代においても、授業改善は教師に求められることである。教師は、よりよい授業をしたいと願うものの、本質的に授業はおもしろくないものとして、子どもたちには認識されているのが現状である。本研究では、共有ビジョンである「目指す生徒像」を軸とした協働的な授業改善の取り組みを報告する。そして、「目指す生徒像」を教職員が一丸となって作り、解釈、実践、検討していく営みの中で、生徒の実態や授業の問題点を明確に認識し、同じ視点での授業の改善や学校の組織力の向上につながる可能性を見出すこととする。さらに、こうした取り組みを進めていく中で、教師一人ひとりのメンタル・モデルにどのようにアプローチしていくのかということの視座も明らかにしていくこととする