# A Review on Internet of Things for Defense and Public Safety
## 5 Building IoT for Tactical and Emergency Environments
### Computation
#### 5.4.2 Cloud Platforms
It is supported by many Original Equipment Manufacturers (OEM) like Arexx, Nanode, OpenGear, Arduino or mBed. Nimbits [142] connects smart embedded devices to the cloud, it performs data analytics and generates alerts. Moreover, it connects to websites and can store, share and retrieve sensor's data in various formats, including text based, numeric, GPS, JSON or XML. It uses XMPP to exchange data or messages. The core is a server that provides REST web services for logging and retrieving raw and processed data. The authors of [143] summarize some of the characteristics of a number of available cloud platforms. The metrics include: support of gateway devices to bridge the short range network and wide area network, support of discovery, delivery, configuration and activation of services, provision of a proactive and reactive assurance of platform, support of accounting and billing of services, and, finally, support of standard application protocols. All the platforms analyzed by the authors support sensing or actuation devices, a user interface to interact with them, and a web component to run the business logic of the application on the cloud. None of such platforms supports the DDS protocol. [PERSON] et al. [144] propose a novel infrastructure to provide application packages on resource-constrained heterogeneous edge devices elastically in large-scale IoT deployments. It enables push-based (commands down to the tactical units) as well as pull-based (from ground to decision-making) deployments supporting different topologies and infrastructure requirements. The efficient use of cloud based resources requires the previous selection of software architectures for both communications and processing. Centralized cloud approaches, in which raw data is transmitted to the cloud for analysis, are non-viable in tactical environments, as some of the main restrictions in military IoT scenarios are time and resources. Furthermore, even if a device has a high-bandwidth link to a local resource, it is not likely that all devices will have good connectivity to the same cloud-based platform. Thus, relying on tactical wireless networks, any approach that requires a centralized cloud infrastructure is not likely to work properly. Moreover, in a centralized cloud infrastructure, processing represents a complex and computationally expensive procedure, which leverages sophisticated big data tools. Finally, there is a significant delay between the time of the IoT data generation and when the results become available. In order to address the issue of distributed infrastructures for IoT data analysis, researchers have started investigating distributed cloud architectures. The idea consists in extending and complementing a small number of large cloud data centers located in the core of the network, where most computational and storage resources are concentrated, with a large number of tiny cloud data centers located at the boundary between the wired Internet and the IoT. This would enable data analysis applications to benefit from the elastic nature of cloud-based resources while pushing the computation closer to the IoT, with obvious advantages in terms of reducing communications overhead and processing times. There is also research to support the processing of raw IoT data close to the source of their generation, particularly, the processing and filtering of raw IoT data and the exploitation of IoT specific computational solutions for data analysis purposes. Several proposals have emerged from the realization that not all the raw data generated are equally important, and that applications might be better served by focusing only on important data. The Quality of Information (QoI) and Value of Information (VoI) concepts arise to extend [PERSON]'s information theory to consider both the probabilistic nature of the uncertainties. These efforts are highly relevant for the military IoT, as the processing and exploitation of the information is made according to the utility for its users.