Tachi S (Japan)

The purpose of this study was to investigate the back posture change and lumbar support position that can reduce driver's seating fatigue by using a muscle potential measurement device and a posture measurement device. We evaluated the back muscle activity and posture measurement in the seated state, and combined them with the results obtained from the posture measurement and driving fatigue evaluations conducted separately for a long period of time. As a result, it was confirmed that the driver's driving fatigue can be reduced by supporting the back position where posture changes occur with a decrease in muscle activity and a large amount of lumbar displacement.

In this study, we investigated the driver's fatigue reduction effect at multiple support positions in order to reduce the driver's fatigue during long driving.We examined each posture change when supporting the lumbar at these multiple support positions.Then, the long time driving experiments using a driving simulator were conducted to evaluate the driving fatigue.Based on these results, we clarified the difference in fatigue reduction effect due to the difference in support position based on biological information and subjective evaluation.

The aim of this investigation is to develop the central exhaustion systems which are clean ventilation system for road tunnels. In order to maintain environment around road tunnel portals, quantitative evaluation of exhaust gas emission from a road tunnel portal with central exhaustion system was numerically investigated. The sliding mesh with continuous moving technique is developed and utilized for ventilation analyses. The results of two-dimensional simulation show the gas emission rate depend on the location and flow rate of the central exhaustion. It revealed that the two-dimensional simulation gives us quantitative information. Three-dimensional attempts were also carried out. Three-dimensional simulation requires much computational time and resources. Then parametric survey is difficult with PC. However, three-dimensional simulations help us to understand the basic mechanism of gas emission at the tunnel portal. The present methods are therefore useful to understand the aerodynamics and environment for tunnel portals. The numerical simulation is one of the key technologies for the development of the clean system.

Recently, World Wide Web plays an essential role in public and business applications such as information publication and electronic commerce, and its reliability is strongly required. Mark-based authentication has therefore started. It evaluates web sites and issues authentication marks to the sites. The marks are displayed on web pages of the sites, and users of the sites can judge their reliability by seeing the marks. This paper describes a web site authentication mark system which realizes generation, presentation and verification of marks. Especially the paper describes : (1) requirements for the system concerning security, usability, response speed, cost, and extensibility, (2) mark verification by digital signatures embedded in marks and by online queries, (3) implementation of verification programs as plug-ins of web browsers, (4) version management by embedded version IDs in marks, (5) life cycle management of marks using databases, (6) examples of the system behavior. The paper also explains reality of the proposed system through evaluations and comparison with previous systems.