## 6 Applications of VSNs
### Battlefield Monitoring  
Nowadays the world is facing many conflicts among different nations. It is leading the peaceful world to an unstable state which is not suitable for mankind and all the creations that exist on Earth. It costs huge resources and takes the life of civilians and other innocent beings which detrimental for society as well as the environment. It is also a major reason for worldwide economic recession. We can consider of a scenario in a mountain area battlefield where different types of target groups such as civilians, enemies, soldiers, important infrastructure and animals coexist [58, 59]. In such a situation, military operations are very sensitive which usually causes negative effects on the society. In this case, virtualization of sensor networks can serve the multiple purposes of sensing the environment, civilians, soldiers, animals and other sort of important features. Deployment of sensor nodes in a particular area and their effective utilization through virtualization can be a very cost effective approach in today's battlefield. In the virtualization of sensor networks the same physical substrate sensor nodes can be used in different virtual networks for sensing temperature, sound, and humidity. It also helps detecting civilians, opponents and soldiers.  
Sensor network virtualization in the battlefield can efficiently incorporate the overall scenario in a battlefield, as shown in the Figure 4. It can also be resource efficient, lessen the threat to civilians and can develop a new paradigm for efficient communication in the battlefield. Soldiers can monitor the battlefield by overseeing the scenario from virtual service providers for identifying sound, detection of the civilians and enemies, animals and the destructive weapons on the battlefield. This scheme can enhance the battlefield scenario as well as can decrease the cost of war and can save the innocent lives of civilian as well as the infrastructure. From a technical point of view, in a battlefield a lot of different types and multi-vendor sensors are deployed which include sound sensors, camera sensors, temperature sensors, motion detection sensors and other different types of sensors.  
The battlefields are divided into different zones. In each zone, there are at least one or more gateway nodes. The gateway nodes work on behalf of the deployed sensor nodes. We can consider gateway based virtualization or individual sensor based virtualization. Gateway based virtualization is comparatively easier to implement. In case of individual sensor based virtualization techniques we should consider the resource constraints of the tiny sensor nodes. In either case a virtual service gateway provides virtual resources to the user level gateway.  
The responsible troops can only access the user level service gateway and can perform operations as they desire. In gateway based virtualization, the gateway nodes receive different types of sensed datasuch as sound, temperature, motion and video. Thus, a gateway node holds different types of information and it can provide specific information to the particular virtual service gateway when necessary. In designing these types of battlefield scenarios, initially it could be expensive, but in the long run it will provide economies of scale and can be cost effective.