IoT, Sensor Networks, RFID,

Ubiquitous Computing Ubiquitous cloud computing refers to the use of Internet resources at any place and any time for any objectives. With ubiquitous sensors, clouds, and mobile devices, we can retrieve information faster and more effectively. Vannevar Bush predicted a dream device in 1945 :“Consider a future device for individual use, which is a sort of mechanized private file and library. It needs a name, and to coin one at random, “memex” will do. A memex is a device in which an individual stores all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility. It is an enlarged intimate supplement to his memory.” What a coincidence ! Today, this “memex” device goes by the name of iPad, smartphone,cloud, IoT, virtual reality, and cyber-physical system (CPS), among many others.

Cloudlets and Clouds Recently, researchers at Carnegie Mellon University, Microsoft, AT&T, and Lancaster University proposed a low-cost infrastructure to enable cloud computing using mobile devices. The idea is called Cloudlet, and it offers a resource-rich portal for upgrading mobile devices with cognitive abilities to access distant clouds. This portal should be designed to be trustworthy and use VMs to explore location-aware cloud applications. Cloudlets are decentralized and self-managed, like a “virtual data center in abox.” Cloudlets operate with LAN latency and bandwidth with only a few users at a time. Clouds are centralized at large-scale data centers. They are professionally administrated all the time and they need large machine rooms with uninterrupted power and cooling. The main problem for a distant cloud to be accessed by mobile devices lies in the long latency experienced with the Internet or WANs.

Cloud Mashup In web application development, a mashup is a web page or application that combines data, presentations, or functionality from two or more sources to create a new service. The main characteristics of the mashup are a combination of virtualization and aggregation. Not only are AWS and GAE different in terms of their functionalities, but they also can complement each other. This has triggered the idea of mashing up different clouds to build an intercloud or cloud of clouds dynamically. This mashup helps a user to write agile software on GAE and use the user inputs to perform parallel computing operations on AWS

IoT In ubiquitous computing, the Internet of Things (IoT) provides a network of sensor or radio connected devices that can be uniquely identified and located in the cyber-physical space. This IoT is mostly wirelessly connected as a self-configuring network of radio-frequency tags, low-cost sensors, or e-labels. The term “IoT” combine RFID technology with today’s IPv6-based Internet technology. All things (objects) have IP addresses, which can be uniquely identified. The IP- identifiable objects are readable, recognizable, locatable, addressable, and/or controllable via the Internet, aided by RFID, WiFi, ZigBee, mobile networks, and GPS.

Technology road map of IoT

IoT Architecture

The bottom layers represent various types of sensing devices: namely RFID tags, ZigBee or other types of sensors, and road-mapping GPS navigators. The sensing devices are locally or wide-area-connected in the form of RFID networks, sensor networks, and GPSes. Signals or information collected at these sensing devices are linked to the applications through the cloud computing platforms at the middle layer. The signal processing clouds are built over the mobile networks, the Internet backbone, and various information networks at the middle layer. A large number of sensors and filters are used to collect the raw data. Various compute and storage clouds and grids are used to process the data and transform it into information and knowledge formats. The sensed information is used to put together a decision-making system for intelligence applications. The middle layer is also considered as a Semantic web or grid.

Application Domain of IoT

RFID RFID is applied with electronic labels or RFID tags on any objects being monitored or tracked. The tagging may be applied to any objects, such as merchandise, tools, smartphones, computers, animals,or people. The purpose is to identify and track the objects using radio waves or sensing signals. Some tags can be read from tens or hundreds of meters away via a wireless reader. There are generally three types of RFID tags: active RFID tags containing a battery and transmitting signals autonomously, passive RFID tags which have no battery and require an external source to provoke signal transmission. battery-assisted passive RFID tags which require an external source to wake up the battery but have significantly higher forward link capability.

In terms of functionality, there are three major components of RFID hardware: • RFID tag A tiny silicon chip attached to a small antenna. • Reader antenna Used to radiate the energy and then capture the return signal sent back from the tag. It can be integrated with a handheld reader device or connected to the reader by cable. • Reader The device station that talks with the tags. A reader may support one or more antennae. Resembling an electronic barcode, a reader device can detect signals even without a line of sight

How RFID works

Wireless Sensor Networks A WSN is a group of specialized transducers with a communications infrastructure intended to monitor and record conditions at diverse locations. Commonly monitored parameters are temperature, humidity, pressure, wind direction and speed, illumination intensity, vibration intensity, sound intensity, power-line voltage, chemical concentrations, pollutant levels, and vital body functions. A sensor network consists of multiple detection stations called sensor nodes, each of which is small, lightweight, and portable. Every sensor node is equipped with a transducer, microcomputer, transceiver, and power source. The transducer generates electrical signals based on sensed data. The microcomputer processes and stores the sensor output. The transceiver, which can be hardwired or wireless, receives commands from a central computer and transmits data to that computer. The power for each sensor node is derived from the electric utility or from a battery. A sensor node may vary in size from that of a shoebox down to a dust grain. The cost of sensor nodes also varies a lot, ranging from $100’s to a few pennies. Size and cost constraints on sensor nodes are often decided by energy, memory, computational speed, and bandwidth of the sensors used.

Four Classes of Wireless Networks

Three Generations of WSN

Applications of WSN • Military sensor networks to detect and gain as much information as possible about enemy movements, explosions, and other phenomena of interest • Sensor networks to detect and characterize chemical, biological, radiological, nuclear, and explosive attacks and materials • Sensor networks to detect and monitor environmental changes in plains, forests, oceans, and so on • Wireless traffic sensor networks to monitor vehicle traffic on highways or in congested parts of a city • Wireless surveillance sensor networks for providing security in shopping malls, parking garages, and other facilities • Wireless parking lot sensor networks to determine whether the lot is occupied or available