SmartDust

What is smart dust? Some people may know about this. Smartdust is a network of very small sensors that can communicate with each other in wireless and ad-hoc maner. Smartdust sensors are more simillar to the normal sensor.

As other sensors smartdust consisted with 3 major components.

1. Mote (processor)
2. Sensor (device to use sense)
3. Radio Link (communicate with other nodes and base station)

Smartdus can detect temperature, humidity, magnetic field, vibration and other messurements. When we apply smartdust in real world thousands of nodes are scattered around the sensor field.

This is a very valuble in military applications. battlefield surveillance, treaty monitoring, transportation monitoring, enemy troops tracking.

image courtesy www-bsac.eecs.berkeley.edu/

Literature

According to the literature found related to the road trac surveillance using wireless sensors there are several prime strategies to recognize identify or detect traffic conditions. Detection with Magnetic Sensors, Video Sensors, Seismic Sensors, Acoustic (audio) Sensors are the main sensors used for those studies. Using the data collected from the sensors researches were analyzed the data using various ways. Then they came up with a mechanism for detect the vehicles/congestions. Most of the time they had used a threshold value for detection.

In the system which was designed in [1] comprised with two main components. Set of sensor nodes an the access point. Sensors are sensing the magnetic fields variation in the earth due to the vehicles and according to those measurements the system identifies the vehicle. For that the correlation between magnetic field and the vehicle level in the road was identified. Further more using a state machine and a threshold value system categorizes the identified vehicles. It is an enhancement for the system.

The solution suggested in the research [2] is to identify the trac status of the road using the GPS sensors. The GPS receiver records timestamp, altitude, speed, distance, heading, and coordinates once every 4 to 10 seconds. To find the correlation of traffic status and the sensing measurements this process was done for several days continuously and extracted some features of trac patterns on road segment. There are three parameters concern with the preliminary data. Those are speed, temporal data and spatial data. To obtain a trac pattern or feature each analysis should be concerned with those three. Without any of these will cause ambiguity in analysis. Finally using the analysis they found an association of trac pattern and the GPS data.

Refferences
[1] Sinem Coleri, Sing Yiu Cheung and Pravin Varaiya, “Sensor Networks for Monitoring Trac”, University of California, Berkeley, August 5, 2004.

[2] Jungkeun Yoon, Brian Noble, Mingyan Liu, “Surface Street Trac Estimation”, Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2122.

Sensor Networks in real world

The sensor networks can be used for various application areas. For those application areas, there are different technical issues that researchers are currently resolving. In the deployment time sensors are used wireless ad-hoc networking features. Since sensor networking used in various areas it should have domain specific networking features such as protocols and algorithms. The sensors are scattered over the area that we want to extract data we called sensor field. Each scattered sensor can gather data from sensor field and process that if it is necessary. Then the information gathered by that node is routed to a gathering point that called sink. From the sink we can use that gathered information.

There are some design issues to be considered in sensor networking. First one is fault tolerance. Some nodes may not work as expected. In that case failure nodes should not affect to the entire network functionality. Power consumption is very important in the sensor networking. Sensor is a battery powered device and in some occasions we can’t change those batteries frequently (Military applications). Therefore we should have power saving methods to long last these nodes. Bandwidth in sensor nodes is not much higher. Therefore we should manage that with our resources. The sensor networking is currently used in many areas. Such as monitoring habitat, Military applications, Vehicle Monitoring, Disaster management systems, Chemical and Biological sensors etc...

Sensor

Sensor is a device. Sensors are used in everyday life. Applications include automobiles, machines, aerospace, medicine, industry and robotics. A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations. The development of wireless sensor networks was originally motivated by military applications such as battlefield surveillance. However, wireless sensor networks are now used in many civilian application areas, including environment and habitat monitoring, healthcare applications, home automation, and traffic control.

content courtesy www.wikipedia.com