Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- A scalable and efficient approach for obtaining measurements in CAN-Based control systemsPublication . Andersson, Björn; Pereira, Nuno; Elmenreich, Wilfried; Tovar, Eduardo; Pacheco, Filipe; Cruz, NunoThe availability of small inexpensive sensor elements enables the employment of large wired or wireless sensor networks for feeding control systems. Unfortunately, the need to transmit a large number of sensor measurements over a network negatively affects the timing parameters of the control loop. This paper presents a solution to this problem by representing sensor measurements with an approximate representation-an interpolation of sensor measurements as a function of space coordinates. A priority-based medium access control (MAC) protocol is used to select the sensor messages with high information content. Thus, the information from a large number of sensor measurements is conveyed within a few messages. This approach greatly reduces the time for obtaining a snapshot of the environment state and therefore supports the real-time requirements of feedback control loops.
- Using a prioritized medium access control protocol for incrementally obtaining an interpolation of sensor readingsPublication . Andersson, Björn; Pereira, Nuno; Tovar, Eduardo; Gomes, RicardoThis paper addresses sensor network applications which need to obtain an accurate image of physical phenomena and do so with a high sampling rate in both time and space. We present a fast and scalable approach for obtaining an approximate representation of all sensor readings at high sampling rate for quickly reacting to critical events in a physical environment. This approach is an improvement on previous work in that after the new approach has undergone a startup phase then the new approach can use a very small sampling period.
- Efficient computation of min and max sensor values in multihop networksPublication . Pereira, Nuno; Andersson, Björn; Tovar, Eduardo; Carvalho, PauloConsider a wireless sensor network (WSN) where a broadcast from a sensor node does not reach all sensor nodes in the network; such networks are often called multihop networks. Sensor nodes take individual sensor readings, however, in many cases, it is relevant to compute aggregated quantities of these readings. In fact, the minimum and maximum of all sensor readings at an instant are often interesting because they indicate abnormal behavior, for example if the maximum temperature is very high then it may be that a fire has broken out. In this context, we propose an algorithm for computing the min or max of sensor readings in a multihop network. This algorithm has the particularly interesting property of having a time complexity that does not depend on the number of sensor nodes; only the network diameter and the range of the value domain of sensor readings matter.