IEEE802.15.4 is a standard designed for low rate wireless personal area network. For its MAC protocol adopts the competition method to share wireless channel, collisions between ending devices are unavoidable and lead to retransmissions, consuming more energy. As traffic load becomes heavier, collisions and retransmissions are more serious. The focus of this paper is to achieve dynamic-paramete...

Traffic flow at low densities (free traffic) is characterized by a quasi-one-dimensional relation between traffic flow and vehicle density, while no such fundamental diagram exists for ‘synchronized’ congested traffic flow. Instead, a two-dimensional area of widely scattered flow-density data is observed as a consequence of a complex traffic dynamics. For an explanation of this phenomenon and t...

In this paper, we develop an Intelligent Wheelchair (IW) system to provide safe mobility to the disabled or elderly people with cognitive and motor impairments. Our IW provides two main functions: obstacle avoidance and situation awareness. Firstly, it detects a variety of obstacles by a combination of a camera and 8 range sensors, and finds the viable paths to avoid the collisions of obstacles...

The objective of this study was to identify, among motorcyclists involved in traffic incidents, the factors associated with risk of injuries. In 2004, in the city of Maringá-PR, it was determined that there were a total of 2,362 motorcyclists involved in traffic incidents, according to records from the local Military Police. Multivariate analysis was applied to identify the factors associated w...

IEEE 802.15.4 is the Low-Rate Wireless Personal Area Network (LR-WPAN) standard that is suitable for wireless sensor networks and wireless home networks among others. The IEEE 802.15.4 is specifically designed for energy efficiency since many 802.15.4-compliant devices are expected to operate on battery. Because of inadequate design of the downlink frame transmission mechanism in the standard, ...

Since Japan is a rapidly aging society, ensuring the safety of older drivers is a major issue in the future. This study analyzed the number of traffic accidents by age group, and investigated the characteristics of accidents involving older drivers. It was found, for example, that regardless of age, there were more rear-end and front-to-side collisions, although older drivers had fewer rear-end...

Autonomous driving vehicles are becoming popular as a solution to reach safe, efficient and comfortable mobility. However, at early market penetration, autonomous vehicles based on Cooperative ACC (C-ACC) policies will have to co-exist in mixed traffic conditions with less autonomous vehicles, such as Adaptive Cruise Control (ACC) or conventional vehicles. In this paper, we introduce a simple c...

BACKGROUND The mechanism and pattern of vascular injury vary between different populations. The commonest mechanism of vascular injury in civilian practice is road traffic collisions. We aimed to prospectively study the incidence, detailed mechanism and anatomical distribution of hospitalized vascular trauma patients following road traffic collisions in a high-income developing country. METHO...