Development of a hull form definition tool with a related knowledge-based advisory system

The development of a parametric hull form design system utilizing combined knowledge-based and objectoriented methodologies, approaches, and techniques is the major purpose of this research. One objective was the development of a powerful, intuitive, and parameter-based hull definition system with a related hull definition advisory system that would provide useful and necessary advice to the user. Object and knowledge modeling activities were conducted during the analysis and design stage to facilitate the implementation of a hull design program and advisory system. The hull design system includes the generation of a geometric model from a process of aggregating simple user-selected shapes representing different boundaries. Design involves the capability to vary simple parameters such as entrance angles, length-breadth ratios, and radii to define local and general surface geometries. Hydrostatic calculations are included for analysis; results are referred to an advisory system for evaluation and the determination of the acceptability of parameters and analysis results. The advisory system includes a knowledge bases consisting of hull form databases, results of the statistical analysis of data, design parameter constraints, and expert knowledge acquired from designers, reference materials, and technical reports. Use of the design tool with the advisory system results in the rapid generation of hull forms and associated design evaluations. Flexibility in decision making results from the separation of the design system from the advisory system. The independence of the two systems allows for a wide range of user experience with experts using the design tool with minimal reference to the advisory system. On the other hand, the expertise and knowledge stored in the advisory system is fully available to inexperienced designers and users.     

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.     

H ∞ control design to include nonlinearities. First report: saturation of the rudder

In designing a control system for large vessels, there are two kinds of nonlinearities which must be considered. One is the nonlinearity in equations of motion and the other is the saturation in control devices such as engine output or rudders. These nonlinearities can strongly affect the performance of the control system. A new method to deal with the nonlinearity of saturation has been proposed in this paper. The saturation is considered as a variation of gain in the system. A control system with gain variation can be designed by H _∞ control theory. As an example, a course-keeping control system for a course-unstable ship has been presented. The results show that the method proposed is effective. Received for publication on Jan. 26, 2000; accepted on April 4, 2000     

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.     

H∞ control design to include nonlinearities. Second report: nonlinearities in equations of motion

In our first report, a method to deal with the nonlinearity of saturation was proposed. A method of dealing with nonlinearity in equations of motion is proposed in this paper. The nonlinear equations of motion are expressed as variations of linear equations of motion. The nonlinear equations can be linearized around a specific point with a tangential plane or line. Accordingly, nonlinear equations effective in a certain domain can be obtained by variations in this tangential line. A control system with varying elements can be designed using the general H _∞ control theory. As an example, we present a speed and heading changing system for large vessels at low speeds during berthing maneuvers, where the equation will vary during motion. The nonlinearity of the equations is caused by the speeds. The control system is essentially designed to be robust in disturbance and noise. In this example, the saturation in the propeller is also considered using the method proposed in the first report. The results show that the method proposed in this paper is effective. Received: February 20, 2001 / Accepted: December 11, 2001     

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.