Fieldbus networks: real-time from the perspective of the application tasks

Fieldbus communication networks aim to interconnect sensors, actuators and controllers within distributed computer-controlled systems. Therefore they constitute the foundation upon which real-time applications are to be implemented. A potential leap towards the use of fieldbus in such time-critical applications lies in the evaluation of its temporal behaviour. In the past few years several research works have been performed on a number of fieldbuses. However, these have mostly focused on the message passing mechanisms, without taking into account the communicating application tasks running in those distributed systems. The main contribution of this paper is to provide an approach for engineering real-time fieldbus systems where the schedulability analysis of the distributed system integrates both the characteristics of the application tasks and the characteristics of the message transactions performed by these tasks. In particular, we address the case of system where the Process-Pascal multitasking language is used to develop P-NET based distributed applications

Analysis of the mismatch between school furniture and children

The characteristics of school furniture are strongly associated with back and neck pain, referred by school-aged children. In Portugal, about 60% of the adolescents involved in a recent study reported having felt back pain at least once in the last three months. The aim of this study was to compare furniture sizes of the 2 types indicated for primary schools, within 9 schools, with the anthropometric characteristics of Portuguese students, in order to evaluate the mismatch between them. The sample consisted of 432 volunteer students. Regarding the methodology, 5 anthropometric measures were gathered, as well as 5 dimensions from the school furniture. For the evaluation of classroom furniture, a (mis)match criterion equation was defined. Results indicated that there is a significant mismatch between furniture dimensions and the anthropometric characteristics of the students.