日本超导磁悬浮列车的技术开发

介绍了日本超导磁悬浮列车技术开发方面取得的成果,以及2016年前的研发计划。     

Solutions for urban traffic issues by ITS technologies

In recent years, traffic congestion, traffic accidents, and deterioration of the environment because of growing population, increasing urbanization, and increasing car ownership have become serious problems in the Asia-Pacific regions. Intelligent transport systems (ITS) are systems that try to solve various road traffic issues using information communication technologies. Several countries are endeavoring to solve such traffic issues by deploying an ITS and achieving positive results. However, there are some problems in advancing ITS deployment in these countries, such as lack of technical know-how, a lack of coordination among systems, lack of a master plan, and financial constraints. In order to introduce ITSs, it is important to select suitable technologies and applications appropriate for each country. An appropriate plan and evaluation of the ITS project are also important for the introduction of ITS.In this paper, we propose methods for the utilization and introduction of ITS technologies to solve urban traffic issues in various countries, based on the lessons learned from the deployment of an ITS in Japan.     

MaaS trends and policy-level initiatives in the EU

The concept of mobility-as-a-service (MaaS) was conceived in Finland, and it is characteristically user-oriented. Interest in MaaS has quickly spread across Europe along with the rapid advances in information and communications technology and the internet of things in recent years, as the realization of MaaS is consistent with the policy directions of the EU member states promoting the use of public transport.This paper describes the MaaS concept in EU, the birth of the concept in Finland and its background, and EU-wide policy level initiatives and their characteristics.     

Field operational tests of Smartway in Japan

Efforts are underway in Japan to promote “Smartway” next-generation roadways, which provide a variety of services through the use of advanced ITS technologies. In recent years, the National Institute for Land and Infrastructure Management (NILIM), part of the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), has conducted public-private joint research on next-generation road services using ITS technologies. Field operational tests (FOTs) of services including forward obstacle information provision and merging assistance using 5.8 GHz dedicated short range communication (DSRC) were conducted on the Tokyo Metropolitan Expressway through FY2007. In FY2008-2009, FOTs were conducted in three major metropolitan areas—Tokyo, Nagoya, and Keihanshin (Kyoto, Osaka, and Kobe)—to promote future deployment nationwide. These included tests of information provision services to alert drivers to forward obstacles hidden beyond the crest of an incline and prevent excessive speed on sharp curves. This paper presents an overview of these FOTs conducted by NILIM in recent years and their results.     

Relation between the lifting surface theory and the lifting line theory in the design of an optimum screw propeller

A theory on an optimum screw propeller is described. The optimum means optimum efficiency of a propeller, that is, maximizing thrust horse power for a given shaft horse power. The theory is based on the propeller lifting surface theory. Circulation density (lift density) of the blade is determined by the lifting surface theory on a specified condition in general. However, it is shown that, in the case of optimum condition, the circulation density is not determined by the lifting surface theory, although the circulation distribution which is the chordwise integral of the circulation density is determined. The reason is that the governing equation of the optimization by the lifting surface theory is reduced to that by the lifting line theory. This theoretical deduction is the main part of this paper. The importance of the lifting line theory in the design of the optimum propeller is made clear. Numerical calculations support the conclusion from the deduction. This is shown in the case of freely running propellers and in the case of wake adapted propellers.     

Active Steering Systems Based on Model Reference Adaptive Nonlinear Control

This paper presents a model reference adaptive nonlinear control strategy for active steering of a two wheel steering car which is realized by steer-by-wire technology. The ideal fixed property of a steering system, which is provided by a reference model, is attained by D * control. The proposed method can treat the nonlinear relationships between the slip angles and the lateral forces on tires, and the uncertainties on the friction of the road surface, whose compensations are very important under critical situations. Some results of realtime simulation with a steering equipment show the effectiveness of the proposed method.     

A study on the estimation of the seaquake response of a floating structure considering the characteristics of seismic wave propagation in the ground and the water

 Seaquakes, which are characterized by the propagation of vertical earthquake motion at the sea bottom as a compression (longitudinal) wave, are reported to cause damage to ships, and their effect on floating structures is a matter of great concern. To comprehend the basic properties of seaquakes, we first discuss a method to calculate the displacement of the seabed when it is subjected to hydrodynamic pressure. To investigate the interrelationship between the vibration of a floating structure and the deformation of the seabed, a new boundary integral equation is derived which assumes that the seabed is a semiinfinite homogeneous elastic solid in order to analyze the seaquake-induced hydrodynamic pressure acting on the floating structure. By considering the propagation of the seismic wave in the ground and in the water, the incident wave potential in seaquake problems is also deduced and its characteristics are discussed. Finally, the response of a very large floating structure in a seaquake is investigated using a fluid force analysis method, and considering the interrelationship between the vibration of the floating structure and the deformation of the seabed. Received: August 19, 2002 / Accepted: November 11, 2002 Address correspondence to: H. Takamura (hiroaki_takamura@nishimatsu.co.jp) Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;189:87–92,93–100 and 190:381–386)